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Sample records for sorption coefficient koc

  1. The adsorption coefficient (KOC) of chlorpyrifos in clay soil

    International Nuclear Information System (INIS)

    Halimah Muhamad; Nashriyah Mat; Tan Yew Ai; Ismail Sahid

    2005-01-01

    The purpose of this study was to determine the adsorption coefficient (KOC) of chlorpyrifos in clay soil by measuring the Freundlich adsorption coefficient (Kads(f)) and desorption coefficient (1/n value) of chlorpyrifos. It was found that the Freundlich adsorption coefficient (Kads(f)) and the linear regression (r2) of the Freundlich adsorption isotherm for chlorpyrifos in the clay soil were 52.6 L/kg and 0.5244, respectively. Adsorption equilibrium time was achieved within 24 hours for clay soil. This adsorption equilibrium time was used to determine the effect of concentration on adsorption. The adsorption coefficient (KOC) of clay soil was found to be 2783 L/kg with an initial concentration solution of 1 μg/g, soil-solution ratio (1:5) at 300 C when the equilibrium between the soil matrix and solution was 24 hours. The Kdes decreased over four repetitions of the desorption process. The chlorpyrifos residues may be strongly adsorbed onto the surface of clay. (Author)

  2. PREDICTING SOIL SORPTION COEFFICIENTS OF ORGANIC CHEMICALS USING A NEURAL NETWORK MODEL

    Science.gov (United States)

    The soil/sediment adsorption partition coefficient normalized to organic carbon (Koc) is extensively used to assess the fate of organic chemicals in hazardous waste sites. Several attempts have been made to estimate the value of Koc from chemical structure ...

  3. Sorption of phenanthrene on agricultural soils

    DEFF Research Database (Denmark)

    Soares, Antonio; Møldrup, Per; Minh, Luong Nhat

    2013-01-01

    Polyaromatic hydrocarbon (PAH) sorption to soil is a key process deciding the transport and fate of PAH, and potential toxic impacts in the soil and groundwater ecosystems, for example in connection with atmospheric PAH deposition on soils. There are numerous studies on PAH sorption in relatively......, 0.25–1-m depth) by the single-point adsorption method. The organic carbon partition coefficient, KOC (liter per kilogram) for topsoils was found generally to fall between the KOC values estimated by the two most frequently used models for PAH partitioning, the Abdul et al. (Hazardous Waste...... & Hazardous Materials 4(3):211–222, 1987) model and Karickhoff et al. (Water Research 13:241–248, 1979) model. A less-recognized model by Karickhoff (Chemosphere 10:833–846, 1981), yielding a KOC of 14,918 L kg−1, closely corresponded to the average measured KOC value for the topsoils, and this model...

  4. Evaluation of sorption distribution coefficient of Cs onto granite using sorption data collected in sorption database and sorption model

    International Nuclear Information System (INIS)

    Nagasaki, S.

    2013-01-01

    Based on the sorption distribution coefficients (K d ) of Cs onto granite collected from the JAERI Sorption Database (SDB), the parameters for a two-site model without the triple-layer structure were optimized. Comparing the experimentally measured K d values of Cs onto Mizunami granite carried out by JAEA with the K d values predicted by the model, the effect of the ionic strength on the K d values of Cs onto granite was evaluated. It was found that K d values could be determined using the content of biotite in granite at a sodium concentration ([Na]) of 1 x 10 -2 to 5 x 10 -1 mol/dm 3 . It was suggested that in high ionic strength solutions, the sorption of Cs onto other minerals such as microcline should also be taken into account. (author)

  5. Evaluation of sorption distribution coefficient of Cs onto granite using sorption data collected in sorption database and sorption model

    Energy Technology Data Exchange (ETDEWEB)

    Nagasaki, S., E-mail: nagasas@mcmaster.ca [McMaster Univ., Hamilton, Ontario (Canada)

    2013-07-01

    Based on the sorption distribution coefficients (K{sub d}) of Cs onto granite collected from the JAERI Sorption Database (SDB), the parameters for a two-site model without the triple-layer structure were optimized. Comparing the experimentally measured K{sub d} values of Cs onto Mizunami granite carried out by JAEA with the K{sub d} values predicted by the model, the effect of the ionic strength on the K{sub d} values of Cs onto granite was evaluated. It was found that K{sub d} values could be determined using the content of biotite in granite at a sodium concentration ([Na]) of 1 x 10{sup -2} to 5 x 10{sup -1} mol/dm{sup 3} . It was suggested that in high ionic strength solutions, the sorption of Cs onto other minerals such as microcline should also be taken into account. (author)

  6. Sorption Coefficients for Iodine, Silver, and Cesium on Dust Particles

    International Nuclear Information System (INIS)

    Stempniewicz, M.M.; Goede, P.

    2014-01-01

    This paper describes the work performed to find relevant experimental data and find the sorption coefficients that represent well the available data for cesium, iodine, and silver on dust particles. The purpose of this work is to generate a set of coefficients that may be recommended for the computer code users. The work was performed using the computer code SPECTRA. Calculations were performed for the following data: • I-131 on AVR dust; • Ag-110m on AVR dust; • Cs-13 and Cs-137 on AVR dust. Available data was matched using the SPECTRA Sorption Model. S = A(T) · C_V-B(T) · C_d. The results are summarized as follows: • The available data can be correlated. The data scatter is about 4 orders of magnitude. Therefore the coefficients of the Langmuir isotherms vary by 4 orders of magnitude. • Sorption rates are higher at low temperatures and lower at high temperatures. This tendency has been observed in the data compiled at Oak Ridge. It is therefore surmised that the highest value of the sorption coefficients are appropriate for the low temperatures and the lowest value of the sorption coefficients are appropriate for the high temperatures. The recommended sorption coefficients are presented in this paper. • The present set of coefficients is very rough and should be a subject for future verification against experimental data. (author)

  7. Compilation of radionuclide sorption coefficients for performance assessment

    Energy Technology Data Exchange (ETDEWEB)

    Carbol, P.; Engkvist, I. [PI Chemical Consulting HB, Landvetter (Sweden)

    1997-09-01

    The report presents four possible site-specific conditions in Sweden. The different sorption mechanisms applicable to the studied elements together with the K{sub d} concept are shortly summarised. The influence of organic substances present in the groundwater on the element`s sorption and mobility is also discussed. Criteria for selection of K{sub d} values are presented together with sensitivity of the values to pH, E{sub h} and salinity. Sorption coefficients are recommended for elements in the repository with half-life above 5.3 years. The elements reviewed are: Cs, Sr, Ra, Ln, Ac, Th, Pa, U, Np, Pu, Am, Cm, Co, Ni, Cd, Zr, Nb, Tc, Pd, Ag, Sn, C, I, Cl, Se and Kr. For every element there is a recommendation of a realistic K{sub d} value with an uncertainty limit. The selection is based on experimental investigations or chemical analogues. In some cases few or no K{sub d} data were found, and it is recommended that sorption studies be performed on elements such as Cd, Pa, Cm, Zr, Nb, Pd, Ag and Sn. The recommended K{sub d} values for the different element`s sorption on granitic rock, serve as a guidance of the sorption performance 87 refs, 18 tabs

  8. Compilation of radionuclide sorption coefficients for performance assessment

    International Nuclear Information System (INIS)

    Carbol, P.; Engkvist, I.

    1997-09-01

    The report presents four possible site-specific conditions in Sweden. The different sorption mechanisms applicable to the studied elements together with the K d concept are shortly summarised. The influence of organic substances present in the groundwater on the element's sorption and mobility is also discussed. Criteria for selection of K d values are presented together with sensitivity of the values to pH, E h and salinity. Sorption coefficients are recommended for elements in the repository with half-life above 5.3 years. The elements reviewed are: Cs, Sr, Ra, Ln, Ac, Th, Pa, U, Np, Pu, Am, Cm, Co, Ni, Cd, Zr, Nb, Tc, Pd, Ag, Sn, C, I, Cl, Se and Kr. For every element there is a recommendation of a realistic K d value with an uncertainty limit. The selection is based on experimental investigations or chemical analogues. In some cases few or no K d data were found, and it is recommended that sorption studies be performed on elements such as Cd, Pa, Cm, Zr, Nb, Pd, Ag and Sn. The recommended K d values for the different element's sorption on granitic rock, serve as a guidance of the sorption performance

  9. Sorption of citalopram, irbesartan and fexofenadine in soils: Estimation of sorption coefficients from soil properties.

    Science.gov (United States)

    Klement, Aleš; Kodešová, Radka; Bauerová, Martina; Golovko, Oksana; Kočárek, Martin; Fér, Miroslav; Koba, Olga; Nikodem, Antonín; Grabic, Roman

    2018-03-01

    The sorption of 3 pharmaceuticals, which may exist in 4 different forms depending on the solution pH (irbesartan in cationic, neutral and anionic, fexofenadine in cationic, zwitter-ionic and anionic, and citalopram cationic and neutral), in seven different soils was studied. The measured sorption isotherms were described by Freundlich equations, and the sorption coefficients, K F (for the fixed n exponent for each compound), were related to the soil properties to derive relationships for estimating the sorption coefficients from the soil properties (i.e., pedotransfer rules). The largest sorption was obtained for citalopram (average K F value for n = 1 was 1838 cm 3  g -1 ) followed by fexofenadine (K F  = 35.1 cm 3/n μg 1-1/n g -1 , n = 1.19) and irbesartan (K F  = 3.96 cm 3/n μg 1-1/n g -1 , n = 1.10). The behavior of citalopram (CIT) in soils was different than the behaviors of irbesartan (IRB) and fexofenadine (FEX). Different trends were documented according to the correlation coefficients between the K F values for different compounds (R IRB,FEX  = 0.895, p-valuesoil properties in the pedotransfer functions. While the K F value for citalopram was positively related to base cation saturation (BCS) or sorption complex saturation (SCS) and negatively correlated to the organic carbon content (Cox), the K F values of irbesartan and fexofenadine were negatively related to BCS, SCS or the clay content and positively related to Cox. The best estimates were obtained by combining BCS and Cox for citalopram (R 2  = 93.4), SCS and Cox for irbesartan (R 2  = 96.3), and clay content and Cox for fexofenadine (R 2  = 82.9). Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Separating the effects of organic matter-mineral interactions and organic matter chemistry on the sorption of diuron and phenanthrene.

    Science.gov (United States)

    Ahangar, Ahmad Gholamalizadeh; Smernik, Ronald J; Kookana, Rai S; Chittleborough, David J

    2008-06-01

    Even though it is well established that soil C content is the primary determinant of the sorption affinity of soils for non-ionic compounds, it is also clear that organic carbon-normalized sorption coefficients (K(OC)) vary considerably between soils. Two factors that may contribute to K(OC) variability are variations in organic matter chemistry between soils and interactions between organic matter and soil minerals. Here, we quantify these effects for two non-ionic sorbates-diuron and phenanthrene. The effect of organic matter-mineral interactions were evaluated by comparing K(OC) for demineralized (HF-treated) soils, with K(OC) for the corresponding whole soils. For diuron and phenanthrene, average ratios of K(OC) of the HF-treated soils to K(OC) of the whole soils were 2.5 and 2.3, respectively, indicating a substantial depression of K(OC) due to the presence of minerals in the whole soils. The effect of organic matter chemistry was determined by correlating K(OC) against distributions of C types determined using solid-state (13)C NMR spectroscopy. For diuron, K(OC) was positively correlated with aryl C and negatively correlated with O-alkyl C, for both whole and HF-treated soils, whereas for phenanthrene, these correlations were only present for the HF-treated soils. We suggest that the lack of a clear effect of organic matter chemistry on whole soil K(OC) for phenanthrene is due to an over-riding influence of organic matter-mineral interactions in this case. This hypothesis is supported by a correlation between the increase in K(OC) on HF-treatment and the soil clay content for phenanthrene, but not for diuron.

  11. The effects of organic matter-mineral interactions and organic matter chemistry on diuron sorption across a diverse range of soils.

    Science.gov (United States)

    Smernik, Ronald J; Kookana, Rai S

    2015-01-01

    Sorption of non-ionic organic compounds to soil is usually expressed as the carbon-normalized partition coefficient (KOC), because it is assumed that the main factor that influences the amount sorbed is the organic carbon content of the soil. However, KOC can vary by a factor of at least ten across a range of soils. We investigated two potential causes of variation in diuron KOC - organic matter-mineral interactions and organic matter chemistry - for a diverse set of 34 soils from Sri Lanka, representing a wide range of soil types. Treatment with hydrofluoric acid (HF-treatment) was used to concentrate soil organic matter. HF-treatment increased KOC for the majority of soils (average factor 2.4). We attribute this increase to the blocking of organic matter sorption sites in the whole soils by minerals. There was no significant correlation between KOC for the whole soils and KOC for the HF-treated soils, indicating that the importance of organic matter-mineral interactions varied greatly amongst these soils. There was as much variation in KOC across the HF-treated soils as there was across the whole soils, indicating that the nature of soil organic matter is also an important contributor to KOC variability. Organic matter chemistry, determined by solid-state (13)C nuclear magnetic resonance (NMR) spectroscopy, was correlated with KOC for the HF-treated soils. In particular, KOC increased with the aromatic C content (R=0.64, p=1×10(-6)), and decreased with O-alkyl C (R=-0.32, p=0.03) and alkyl C (R=-0.41, p=0.004) content. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. Application of HPLC capacity coefficients to characterize the sorption of polycyclic aromatic compounds to humic acid

    DEFF Research Database (Denmark)

    Nielsen, T.; Helweg, C.; Siigur, K.

    1997-01-01

    The sorption coefficients to humic acid of 46 PAC having a wide range in polarity were compared with the capacity coefficients of the PAC to a non-polar HPLC column material (ODS) and a polar one (Diol). It is shown that polar interactions contribute to the sorption of polar PAC in addition...

  13. Determination of Sorption Coefficient of Phosphorus Applied for Sugarcane Production in Southwestern Florida.

    Science.gov (United States)

    Muwamba, A; Nkedi-Kizza, P; Morgan, K T

    2016-09-01

    Phosphorus is among the essential nutrients applied to sugarcane ( L.) fields in the form of a fertilizer mixture (N, P, and K) in southwestern Florida. Sorption coefficient is used for modeling P movement, and in this study, we hypothesized that the sorption coefficient determined using fertilizer mixture (N, P, and K) will be significantly different from values determined using KCl and CaCl, the electrolytes most commonly used for conducting sorption experiments. Supporting electrolytes, 0.01 mol L KCl, 0.005 mol L CaCl, deionized (DI) water, simulated Florida rain, and fertilizer mixture prepared in Florida rain were used to characterize P sorption. Immokalee (Sandy, siliceous, hyperthermic Arenic Alaquods) and Margate (Sandy, siliceous hyperthermic Mollic Psammaquents) are the dominant mineral soils used for sugarcane production in southwestern Florida; we used the A and B horizons of Margate soil and the A and B horizons of the Immokalee soil for sorption experiments in this study. Freundlich sorption isotherms described P sorption data. The Freundlich sorption isotherm coefficients followed the trend 0.005 mol L CaCl > 0.01 mol L KCl ≈ fertilizer mixture > simulated Florida rain ≈ DI water. Sorption coefficients were used for modeling P movement with HYDRUS 1D; similar P results were obtained with the 0.01 mol L KCl and fertilizer mixture electrolyte treatments. The sorption coefficient for DI water and simulated Florida rain overpredicted P movement. The P sorption data showed the importance of choosing the appropriate electrolyte for conducting experiments based on the composition of fertilizer. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  14. Estimation of the soil-water partition coefficient normalized to organic carbon for ionizable organic chemicals

    DEFF Research Database (Denmark)

    Franco, Antonio; Trapp, Stefan

    2008-01-01

    The sorption of organic electrolytes to soil was investigated. A dataset consisting of 164 electrolytes, composed of 93 acids, 65 bases, and six amphoters, was collected from literature and databases. The partition coefficient log KOW of the neutral molecule and the dissociation constant pKa were...... calculated by the software ACD/Labs®. The Henderson-Hasselbalch equation was applied to calculate dissociation. Regressions were developed to predict separately for the neutral and the ionic molecule species the distribution coefficient (Kd) normalized to organic carbon (KOC) from log KOW and pKa. The log...... KOC of strong acids (pKa correlated to these parameters. The regressions derived for weak acids and bases (undissociated at environmental pH) were similar. The highest sorption was found for strong bases (pKa > 7.5), probably due to electrical interactions. Nonetheless, their log KOC...

  15. Three-parameter modeling of the soil sorption of acetanilide and triazine herbicide derivatives.

    Science.gov (United States)

    Freitas, Mirlaine R; Matias, Stella V B G; Macedo, Renato L G; Freitas, Matheus P; Venturin, Nelson

    2014-02-01

    Herbicides have widely variable toxicity and many of them are persistent soil contaminants. Acetanilide and triazine family of herbicides have widespread use, but increasing interest for the development of new herbicides has been rising to increase their effectiveness and to diminish environmental hazard. The environmental risk of new herbicides can be accessed by estimating their soil sorption (logKoc), which is usually correlated to the octanol/water partition coefficient (logKow). However, earlier findings have shown that this correlation is not valid for some acetanilide and triazine herbicides. Thus, easily accessible quantitative structure-property relationship models are required to predict logKoc of analogues of the these compounds. Octanol/water partition coefficient, molecular weight and volume were calculated and then regressed against logKoc for two series of acetanilide and triazine herbicides using multiple linear regression, resulting in predictive and validated models.

  16. Plutonium-239 sorption and transport on/in unsaturated sediments. Comparison of batch and column experiments for determining sorption coefficients

    International Nuclear Information System (INIS)

    Jinchuan Xie; Jiachun Lu; Xiaohua Zhou; Xuhui Wang; Mei Li; Lili Du; Yueheng Liu; Guoqing Zhou

    2013-01-01

    Sorption (distribution) coefficients of plutonium were most often derived by static batch experiments. However, it is not clear how unsaturated flow conditions including moisture content and pore water velocity change the sorption coefficients. Transport experiments of plutonium through the unsaturated sediments packed into the columns were then performed in order to determine the sorption coefficients (column-K ds ). Static batch experiments were also conducted to obtain batch-K ds and then compare the differences between batch-K ds and column-K ds . The results show that unsaturated flow conditions had no significant effect on column-K ds , and the average column-K d value was 1.74 ± 0.02 m 3 /kg. By comparison, batch-K d values spanned several orders of magnitude, regardless of the specified liquid-solid conditions. Moreover, the batch-K d (22.7 m 3 /kg) at the standard L/S (4 mL/g) recommended by ASTM D 4319 was over an order of magnitude larger than the average column-K d . (author)

  17. Pesticide sorption and leaching potential on three Hawaiian soils.

    Science.gov (United States)

    Hall, Kathleen E; Ray, Chittaranjan; Ki, Seo Jin; Spokas, Kurt A; Koskinen, William C

    2015-08-15

    On the Hawaiian Islands, groundwater is the principal source of potable water and contamination of this key resource by pesticides is of great concern. To evaluate the leaching potential of four weak acid herbicides [aminocyclopyrachlor, picloram, metsulfuron-methyl, biologically active diketonitrile degradate of isoxaflutole (DKN)] and two neutral non-ionizable herbicides [oxyfluorfen, alachlor], their sorption coefficients were determined on three prevalent soils from the island of Oahu. Metsulfuron-methyl, aminocylcopyrachlor, picloram, and DKN were relatively low sorbing herbicides (K(oc) = 3-53 mL g(-1)), alachlor was intermediate (K(oc) = 120-150 mL g(-1)), and oxyfluorfen sorbed very strongly to the three soils (K(oc) > 12,000 mL g(-1)). Following determination of K(oc) values, the groundwater ubiquity score (GUS) indices for these compounds were calculated to predicted their behavior with the Comprehensive Leaching Risk Assessment System (CLEARS; Tier-1 methodology for Hawaii). Metsulfuron-methyl, aminocyclopyrachlor, picloram, and DKN would be categorized as likely leachers in all three Hawaiian soils, indicating a high risk of groundwater contamination across the island of Oahu. In contrast, oxyfluorfen, regardless of the degradation rate, would possess a low and acceptable leaching risk due to its high sorption on all three soils. The leaching potential of alachlor was more difficult to classify, with a GUS value between 1.8 and 2.8. In addition, four different biochar amendments to these soils did not significantly alter their sorption capacities for aminocyclopyrachlor, indicating a relatively low impact of black carbon additions from geologic volcanic inputs of black carbon. Due to the fact that pesticide environmental risks are chiefly dependent on local soil characteristics, this work has demonstrated that once soil specific sorption parameters are known one can assess the potential pesticide leaching risks. Published by Elsevier Ltd.

  18. Prediction of the glyphosate sorption coefficient across two loamy agricultural fields

    DEFF Research Database (Denmark)

    Paradelo Pérez, Marcos; Norgaard, Trine; Moldrup, Per

    2015-01-01

    , suggesting that different properties control glyphosate sorption in different locations and at different scales of analysis. Better predictions were obtained for the best-four set for the field in Estrup (R2 = 0.87) and for both fields (R2 = 0.70), while the field in Silstrup showed a lower predictability (R......2 = 0.36). Possibly, the low predictability for the field in Silstrup originated from opposing gradients in clay and oxalate-extractable Fe across the field. Also, whereas a lower clay content in Estrup may be the limiting variable for glyphosate sorption, the field in Silstrup has a higher clay...... sorption coefficient, Kd, from easily measurable soil properties in two loamy, agricultural fields in Denmark: Estrup and Silstrup. Forty-five soil samples in Estrup and 65 in Silstrup were collected fromthe surface in a rectangular grid of 15 × 15-mfromeach field, and selected soil properties...

  19. Estimation of sorption coefficients for fungicides in soil and turfgrass thatch

    Energy Technology Data Exchange (ETDEWEB)

    Dell, C.J.; Throssell, C.S.; Bischoff, M. [Purdue Univ., West Lafayette, IN (United States)] [and others

    1994-01-01

    Environmental fates of turf-applied fungicides are not well understood. The role of thatch as a sorptive surface for fungicides has not been evaluated. Thatch may decrease mobility of fungi and decrease their potential to be transported off-site. Batch type sorption studies were conducted to determine sorption coefficients (K{sub f}) for the fungicides triadimefon, [1-(4-chlorophenoxy)-3,3-dimethyl 1-1(1H-1,2,4- triazol-l-g-l) butanone], vinclozolin [3-(3,5-dichlorophenyl)-5-methyl- 5-vinyl-1,3-oxazolidine-2,4-dione], and chloroneb (1,4-dichloro-2,5-dimethoxybenzone) in thatch and in the underlying soil.

  20. Application of radial basis function neural network to predict soil sorption partition coefficient using topological descriptors.

    Science.gov (United States)

    Sabour, Mohammad Reza; Moftakhari Anasori Movahed, Saman

    2017-02-01

    The soil sorption partition coefficient logK oc is an indispensable parameter that can be used in assessing the environmental risk of organic chemicals. In order to predict soil sorption partition coefficient for different and even unknown compounds in a fast and accurate manner, a radial basis function neural network (RBFNN) model was developed. Eight topological descriptors of 800 organic compounds were used as inputs of the model. These 800 organic compounds were chosen from a large and very diverse data set. Generalized Regression Neural Network (GRNN) was utilized as the function in this neural network model due to its capability to adapt very quickly. Hence, it can be used to predict logK oc for new chemicals, as well. Out of total data set, 560 organic compounds were used for training and 240 to test efficiency of the model. The obtained results indicate that the model performance is very well. The correlation coefficients (R2) for training and test sets were 0.995 and 0.933, respectively. The root-mean square errors (RMSE) were 0.2321 for training set and 0.413 for test set. As the results for both training and test set are extremely satisfactory, the proposed neural network model can be employed not only to predict logK oc of known compounds, but also to be adaptive for prediction of this value precisely for new products that enter the market each year. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Predicting Organic Cation Sorption Coefficients: Accounting for Competition from Sorbed Inorganic Cations Using a Simple Probe Molecule.

    Science.gov (United States)

    Jolin, William C; Goyetche, Reaha; Carter, Katherine; Medina, John; Vasudevan, Dharni; MacKay, Allison A

    2017-06-06

    With the increasing number of emerging contaminants that are cationic at environmentally relevant pH values, there is a need for robust predictive models of organic cation sorption coefficients (K d ). Current predictive models fail to account for the differences in the identity, abundance, and affinity of surface-associated inorganic exchange ions naturally present at negatively charged receptor sites on environmental solids. To better understand how organic cation sorption is influenced by surface-associated inorganic exchange ions, sorption coefficients of 10 organic cations (including eight pharmaceuticals and two simple probe organic amines) were determined for six homoionic forms of the aluminosilicate mineral, montmorillonite. Organic cation sorption coefficients exhibited consistent trends for all compounds across the various homoionic clays with sorption coefficients (K d ) decreasing as follows: K d Na + > K d NH 4 + ≥ K d K + > K d Ca 2+ ≥ K d Mg 2+ > K d Al 3+ . This trend for competition between organic cations and exchangeable inorganic cations is consistent with the inorganic cation selectivity sequence, determined for exchange between inorganic ions. Such consistent trends in competition between organic and inorganic cations suggested that a simple probe cation, such as phenyltrimethylammonium or benzylamine, could capture soil-to-soil variations in native inorganic cation identity and abundance for the prediction of organic cation sorption to soils and soil minerals. Indeed, sorption of two pharmaceutical compounds to 30 soils was better described by phenyltrimethylammonium sorption than by measures of benzylamine sorption, effective cation exchange capacity alone, or a model from the literature (Droge, S., and Goss, K. Environ. Sci. Technol. 2013, 47, 14224). A hybrid approach integrating structural scaling factors derived from this literature model of organic cation sorption, along with phenyltrimethylammonium K d values, allowed for

  2. Sorption distribution coefficients of uranium, thorium and radium of selected Malaysian peat soils

    International Nuclear Information System (INIS)

    Mohd Zaidi Ibrahim; Zalina Laili; Muhamat Omar; Phillip, Esther

    2010-01-01

    A study on sorption of uranium, thorium and radium on Malaysian peat soils was conducted to determine their distribution coefficient (K d ) values. Batch studies were performed to investigate the influence of pH and the concentrations of radionuclides. Peat soil samples used in this study were collected from Bachok, Batu Pahat, Dalat, Hutan Melintang and Pekan. The peat samples from different location have different chemical characteristics and K d values. No correlation was found between chemical characteristics and the K d values for radium and thorium, but K d value for uranium was found correlated with humic and organic content. The K d value was found to be influenced by soluble humic substances or humic substances leach out from peat soils. (author)

  3. Evaluating and categorizing the reliability of distribution coefficient values in the sorption database

    International Nuclear Information System (INIS)

    Ochs, Michael; Saito, Yoshihiko; Kitamura, Akira; Shibata, Masahiro; Sasamoto, Hiroshi; Yui, Mikazu

    2007-03-01

    Japan Atomic Energy Agency (JAEA) has developed the sorption database (JNC-SDB) for bentonite and rocks in order to assess the retardation property of important radioactive elements in natural and engineered barriers in the H12 report. The database includes distribution coefficient (K d ) of important radionuclides. The K d values in the SDB are about 20,000 data. The SDB includes a great variety of K d and additional key information from many different literatures. Accordingly, the classification guideline and classification system were developed in order to evaluate the reliability of each K d value (Th, Pa, U, Np, Pu, Am, Cm, Cs, Ra, Se, Tc on bentonite). The reliability of 3740 K d values are evaluated and categorized. (author)

  4. Occurrence and sorption properties of arsenicals in marine sediments

    DEFF Research Database (Denmark)

    Fauser, Patrik; Sanderson, Hans; Hedegaard, Rikke Susanne Vingborg

    2013-01-01

    in marine sediments when conditions are similar to the Baltic Sea. At locations with significant anthropogenic point sources or where the local geology contains volcanic rock and sulphide mineral deposits, there may be significantly elevated arsenic concentrations, and it is recommended to determine on......The content of total arsenic, the inorganic forms: arsenite (As(III)) and arsenate (As(V)), the methylated forms: monomethylarsonic acid and dimethylarsinic acid (DMA), trimethylarsenic oxide, tetramethylarsenonium ion and arsenobetaine was measured in 95 sediment samples and 11 pore water samples...... in the Baltic Sea and other parts of the world. Existing data for on-site measurements of sorption coefficients (Kd) of arsenicals in marine and freshwater sediments show large variability from 1,000 L/kg. In this work, calculated sorption coefficients (Kd and Koc) for As(III+V) showed significant correlation...

  5. Pedotransfer functions for isoproturon sorption on soils and vadose zone materials.

    Science.gov (United States)

    Moeys, Julien; Bergheaud, Valérie; Coquet, Yves

    2011-10-01

    Sorption coefficients (the linear K(D) or the non-linear K(F) and N(F)) are critical parameters in models of pesticide transport to groundwater or surface water. In this work, a dataset of isoproturon sorption coefficients and corresponding soil properties (264 K(D) and 55 K(F)) was compiled, and pedotransfer functions were built for predicting isoproturon sorption in soils and vadose zone materials. These were benchmarked against various other prediction methods. The results show that the organic carbon content (OC) and pH are the two main soil properties influencing isoproturon K(D) . The pedotransfer function is K(D) = 1.7822 + 0.0162 OC(1.5) - 0.1958 pH (K(D) in L kg(-1) and OC in g kg(-1)). For low-OC soils (OC isoproturon sorption in soils in unsampled locations should rely, whenever possible, and by order of preference, on (a) site- or soil-specific pedotransfer functions, (b) pedotransfer functions calibrated on a large dataset, (c) K(OC) values calculated on a large dataset or (d) K(OC) values taken from existing pesticide properties databases. Copyright © 2011 Society of Chemical Industry.

  6. Sorption kinetics of polycyclic aromatic hydrocarbons removal using granular activated carbon: Intraparticle diffusion coefficients

    International Nuclear Information System (INIS)

    Valderrama, C.; Gamisans, X.; Heras, X. de las; Farran, A.; Cortina, J.L.

    2008-01-01

    Granular activated carbon (GAC) was evaluated as a suitable sorbent for polycyclic aromatic hydrocarbons (PAHs) removal from aqueous solutions. For this purpose, kinetic measurements on the extraction of a family of six PAHs were taken. A morphology study was performed by means of a scanning electron microscopy (SEM) analysis of GAC samples. Analyses of the batch rate data for each PAH were carried out using two kinetic models: the homogenous particle diffusion model (HPDM) and the shell progressive model (SPM). The process was controlled by diffusion rate the solutes (PAHs) that penetrated the reacted layer at PAH concentrations in the range of 0.2-10 mg L -1 . The effective particle diffusion coefficients (D eff ) derived from the two models were determined from the batch rate data. The Weber and Morris intraparticle diffusion model made a double contribution to the surface and pore diffusivities in the sorption process. The D eff values derived from both the HPMD and SPM equations varied from 1.1 x 10 -13 to 6.0 x 10 -14 m 2 s -1 . The simplest model, the pore diffusion model, was applied first for data analysis. The model of the next level of complexity, the surface diffusion model, was applied in order to gain a deeper understanding of the diffusion process. This model is able to explain the data, and the apparent surface diffusivities are in the same order of magnitude as the values for the sorption of functionalized aromatic hydrocarbons (phenols and sulphonates) that are described in the literature

  7. Predicting sediment sorption coefficients for linear alkylbenzenesulfonate congeners from polyacrylate-water partition coefficients at different salinities.

    NARCIS (Netherlands)

    Rico Rico, A.; Droge, S.T.J.|info:eu-repo/dai/nl/304834017; Hermens, J.L.M.|info:eu-repo/dai/nl/069681384

    2010-01-01

    The effect of the molecular structure and the salinity on the sorption of the anionic surfactant linear alkylbenzenesulfonate (LAS) to marine sediment has been studied. The analysis of several individual LAS congeners in seawater and of one specific LAS congener at different dilutions of seawater

  8. An axisymmetric diffusion experiment for the determination of diffusion and sorption coefficients of rock samples.

    Science.gov (United States)

    Takeda, M; Hiratsuka, T; Ito, K; Finsterle, S

    2011-04-25

    Diffusion anisotropy is a critical property in predicting migration of substances in sedimentary formations with very low permeability. The diffusion anisotropy of sedimentary rocks has been evaluated mainly from laboratory diffusion experiments, in which the directional diffusivities are separately estimated by through-diffusion experiments using different rock samples, or concurrently by in-diffusion experiments in which only the tracer profile in a rock block is measured. To estimate the diffusion anisotropy from a single rock sample, this study proposes an axisymmetric diffusion test, in which tracer diffuses between a cylindrical rock sample and a surrounding solution reservoir. The tracer diffusion between the sample and reservoir can be monitored from the reservoir tracer concentrations, and the tracer profile could also be obtained after dismantling the sample. Semi-analytical solutions are derived for tracer concentrations in both the reservoir and sample, accounting for an anisotropic diffusion tensor of rank two as well as the dilution effects from sampling and replacement of reservoir solution. The transient and steady-state analyses were examined experimentally and numerically for different experimental configurations, but without the need for tracer profiling. These experimental configurations are tested for in- and out-diffusion experiments using Koetoi and Wakkanai mudstones and Shirahama sandstone, and are scrutinized by a numerical approach to identify favorable conditions for parameter estimation. The analysis reveals the difficulty in estimating diffusion anisotropy; test configurations are proposed for enhanced identifiability of diffusion anisotropy. Moreover, it is demonstrated that the axisymmetric diffusion test is efficient in obtaining the sorption parameter from both steady-state and transient data, and in determining the effective diffusion coefficient if isotropic diffusion is assumed. Moreover, measuring reservoir concentrations in an

  9. An asixymmetric diffusion experiment for the determination of diffusion and sorption coefficients of rock samples

    Energy Technology Data Exchange (ETDEWEB)

    Takeda, M.; Hiratsuka, T.; Ito, K.; Finsterle, S.

    2011-02-01

    Diffusion anisotropy is a critical property in predicting migration of substances in sedimentary formations with very low permeability. The diffusion anisotropy of sedimentary rocks has been evaluated mainly from laboratory diffusion experiments, in which the directional diffusivities are separately estimated by through-diffusion experiments using different rock samples, or concurrently by in-diffusion experiments in which only the tracer profile in a rock block is measured. To estimate the diffusion anisotropy from a single rock sample, this study proposes an axisymmetric diffusion test, in which tracer diffuses between a cylindrical rock sample and a surrounding solution reservoir. The tracer diffusion between the sample and reservoir can be monitored from the reservoir tracer concentrations, and the tracer profile could also be obtained after dismantling the sample. Semi-analytical solutions are derived for tracer concentrations in both the reservoir and sample, accounting for an anisotropic diffusion tensor of rank two as well as the dilution effects from sampling and replacement of reservoir solution. The transient and steady-state analyses were examined experimentally and numerically for different experimental configurations, but without the need for tracer profiling. These experimental configurations are tested for in- and out-diffusion experiments using Koetoi and Wakkanai mudstones and Shirahama sandstone, and are scrutinized by a numerical approach to identify favorable conditions for parameter estimation. The analysis reveals the difficulty in estimating diffusion anisotropy; test configurations are proposed for enhanced identifiability of diffusion anisotropy. Moreover, it is demonstrated that the axisymmetric diffusion test is efficient in obtaining the sorption parameter from both steady-state and transient data, and in determining the effective diffusion coefficient if isotropic diffusion is assumed. Moreover, measuring reservoir concentrations in an

  10. Sorption of pesticides in tropical and temperate soils from Australia and the Philippines.

    Science.gov (United States)

    Oliver, Danielle P; Kookana, Rai S; Quintana, Belen

    2005-08-10

    The sorption behavior of diuron, imidacloprid, and thiacloprid was investigated using 22 soils collected in triplicate from temperate environments in Australia and tropical environments in Australia and the Philippines. Within the temperate environment in Australia, the soils were selected from a range of land uses. The average KOC values (L/kg) for imidacloprid were 326, 322, and 336; for thiacloprid, the values were 915, 743, and 842; and for diuron, the values were 579, 536, and 618 for the Ord (tropical), Mt. Lofty (temperate), and Philippines (tropical) soils, respectively. For all soils, the sorption coefficients decreased in the following order: thiacloprid > diuron > imidacloprid. There were no significant differences in sorption behavior between the tropical soils from the Philippines and the temperate soils from Australia. Sorption was also not significantly related with soil characteristics, namely, organic carbon (OC) content, clay content, and pH, for any of the three chemicals studied. When the data were sorted into separate land uses, the sorption of all three chemicals was highly correlated (P soils from the Philippines. Sorption coefficients for all three chemicals were highly correlated with OC in temperate, native soils only when one extreme value was removed. The relationships between sorption of all three chemicals and OC in temperate, pasture soils were best described by a polynomial. Sorption coefficients for imidacloprid and thiacloprid determined in the temperate pasture soils remained fairly consistent as the OC content increased from 3.3 to 5.3%, indicating that, although the total OC in the pasture soils was increasing, the component of OC involved with sorption of these two compounds may have been remaining constant. This study demonstrated that the origin of the soils (i.e., temperate vs tropical) had no significant effect on the sorption behavior, but in some cases, land use significantly affected the sorption behavior of the three

  11. Removal of dissolved organic carbon by aquifer material: Correlations between column parameters, sorption isotherms and octanol-water partition coefficient.

    Science.gov (United States)

    Pradhan, Snigdhendubala; Boernick, Hilmar; Kumar, Pradeep; Mehrotra, Indu

    2016-07-15

    The correlation between octanol-water partition coefficient (KOW) and the transport of aqueous samples containing single organic compound is well documented. The concept of the KOW of river water containing the mixture of organics was evolved by Pradhan et al. (2015). The present study aims at determining the KOW and sorption parameters of synthetic aqueous samples and river water to finding out the correlation, if any. The laboratory scale columns packed with aquifer materials were fed with synthetic and river water samples. Under the operating conditions, the compounds in the samples did not separate, and all the samples that contain more than one organic compound yielded a single breakthrough curve. Breakthrough curves simulated from sorption isotherms were compared with those from the column runs. The sorption parameters such as retardation factor (Rf), height of mass transfer zone (HMTZ), rate of mass transfer zone (RMTZ), breakpoint column capacity (qb) and maximum column capacity (qx) estimated from column runs, sorption isotherms and models developed by Yoon-Nelson, Bohart-Adam and Thomas were in agreement. The empirical correlations were found between the KOW and sorption parameters. The transport of the organics measured as dissolved organic carbon (DOC) through the aquifer can be predicted from the KOW of the river water and other water samples. The novelty of the study is to measure KOW and to envisage the fate of the DOC of the river water, particularly during riverbank filtration. Statistical analysis of the results revealed a fair agreement between the observed and computed values. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Evaluating and categorizing the reliability of distribution coefficient values in the sorption database (4)

    International Nuclear Information System (INIS)

    Suyama, Tadahiro; Tachi, Yukio; Ganter, Charlotte; Kunze, Susanne; Ochs, Michael

    2011-02-01

    Sorption of radionuclides in bentonites and rocks is one of the key processes in the safe geological disposal of radioactive waste. Japan Atomic Energy Agency (JAEA) has developed sorption database (JAEA-SDB) which includes extensive compilation of sorption K d data by batch experiments, extracted from published literatures. JAEA published the first SDB as an important basis for the H12 performance assessment (PA), and has been continuing to improve and update the SDB in view of potential future data needs, focusing on assuring the desired quality level and practical applications to K d -setting for the geological environment. The JAEA-SDB includes more than 24,000 K d data which are related with various conditions and methods, and different reliabilities. Accordingly, the quality assuring (QA) and classifying guideline/criteria has been developed in order to evaluate the reliability of each K d value. The reliability of K d values of key radionuclides for bentonite, mudstone, granite and Fe-oxide/hydroxide, Al-oxide/hydroxide has been already evaluated. These QA information has been made available to access through the web-based JAEA-SDB since March, 2009. In this report, the QA/classification of selected entries in the JAEA-SDB, focusing on key radionuclides (Th, Np, Am, Se and Cs) sorption on tuff existing widely in geological environment, was done following the approach/guideline defined in our previous report. As a result, the reliability of 560 K d values was evaluated and classified. This classification scheme is expected to make it possible to obtain quick overview of the available data from the SDB, and to have suitable access to the respective data for K d -setting in PA. (author)

  13. A compilation and evaluation of sorption coefficients used in the geosphere model of SYVAC for the 1990 assessment of the Whiteshell Research Area

    Energy Technology Data Exchange (ETDEWEB)

    Vandergraaf, T T; Ticknor, K V

    1994-09-01

    We describe the development of a parametric model that expresses sorption of trace amounts of radioactive and chemically toxic elements from groundwater on geological material as a function of two independent variables: the concentration of the trace element, and the total dissolved solids used to provide sorption coefficients for a contaminant transport model used in performance assessment calculations for a case study of a hypothetical nuclear fuel waste disposal concept in an extensively characterized intrusive rock formation, the Lac du Bonnet batholith. The sorption database in this report is based on laboratory results, literature surveys, and chemical homologs. The arguments used to apply sorption data obtained on unconsolidated material to contaminant transport through intact rock are described. Data are presented for the sorption of 39 elements on three rock types and on 13 primary and secondary minerals, under oxic and anoxic conditions. 166 refs., 12 figs., 4 tabs.

  14. Evaluating and categorizing the reliability of distribution coefficient values in the sorption database (3)

    International Nuclear Information System (INIS)

    Ochs, Michael; Kunze, Susanne; Suyama, Tadahiro; Tachi, Yukio; Yui, Mikazu

    2010-02-01

    Sorption of radionuclides in bentonites and rocks is one of the key processes in the safe geological disposal of radioactive waste. Japan Atomic Energy Agency (JAEA) has developed sorption database (JAEA-SDB) which includes extensive compilation of sorption K d data by batch experiments, extracted from published literatures. JAEA published the first SDB as an important basis for the H12 performance assessment (PA), and has been continuing to improve and update the SDB in view of potential future data needs, focusing on assuring the desired quality level and practical applications to K d -setting for the geological environment. The JAEA-SDB includes more than 24,000 K d data which are related with various conditions and methods, and different reliabilities. Accordingly, the quality assuring (QA) and classifying guideline/criteria has been developed in order to evaluate the reliability of each K d value. The reliability of K d values of key radionuclides for bentonite and mudstone system has been already evaluated. To use these QA information, the new web-based JAEA-SDB was published in March, 2009. In this report, the QA/classification of selected entries for key radionuclides (Th, Np, Am, Se and Cs) in the JAEA-SDB was done following the approach/guideline defined in our previous report focusing granite rocks which are related to reference systems in H12 PA and possible applications in the context of URL activities, and Fe-oxide/hydroxide, Al-oxide/hydroxide existing widely in geological environment. As a result, the reliability of 1,373 K d values was evaluated and classified. This classification scheme is expected to make it possible to obtain quick overview of the available data from the SDB, and to have suitable access to the respective data for K d -setting in PA. (author)

  15. Sorption behaviour of perfluoroalkyl substances in soils.

    Science.gov (United States)

    Milinovic, Jelena; Lacorte, Silvia; Vidal, Miquel; Rigol, Anna

    2015-04-01

    The sorption behaviour of three perfluoroalkyl substances (PFASs), perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA) and perfluorobutane sulfonic acid (PFBS), was studied in six soils with contrasting characteristics, especially in the organic carbon content. Sorption isotherms were obtained by equilibrating the soil samples with 0.01 mol L(-1) CaCl2 solutions spiked with increasing concentrations of the target PFAS. The sorption reversibility of PFASs was also tested for some of the samples. Liquid chromatography coupled to tandem mass spectrometry was used to quantify the target PFASs in the solutions. Both the Freundlich and linear models were appropriate to describe the sorption behaviour of PFASs in soils, and enabled us to derive solid-liquid distribution coefficients (Kd) for each compound in each soil. Kd values increased from 19 to 295 mL g(-1) for PFOS, from 2.2 to 38 mL g(-1) for PFOA and from 0.4 to 6.8 mL g(-1) for PFBS, and were positively correlated with the organic carbon content of the soil. KOC values obtained from the correlations were 710, 96 and 17 mL g(-1) for PFOS, PFOA and PFBS, respectively. Whereas Kd values decreased in the sequence PFOS>PFOA>PFBS, desorption yields were lower than 13% for PFOS, from 24 to 58% for PFOA, and from 32 to 60% for PFBS. This shows that the physicochemical characteristics of PFASs, basically their hydrophobicity, controlled their sorption behaviour in soils, with PFOS being the most irreversibly sorbed PFAS. Copyright © 2014 Elsevier B.V. All rights reserved.

  16. A review of the distribution coefficients of trace elements in soils: influence of sorption system, element characteristics, and soil colloidal properties.

    Science.gov (United States)

    Shaheen, Sabry M; Tsadilas, Christos D; Rinklebe, Jörg

    2013-12-01

    Knowledge about the behavior and reactions of separate soil components with trace elements (TEs) and their distribution coefficients (Kds) in soils is a key issue in assessing the mobility and retention of TEs. Thus, the fate of TEs and the toxic risk they pose depend crucially on their Kd in soil. This article reviews the Kd of TEs in soils as affected by the sorption system, element characteristics, and soil colloidal properties. The sorption mechanism, determining factors, favorable conditions, and competitive ions on the sorption and Kd of TEs are also discussed here. This review demonstrates that the Kd value of TEs does not only depend on inorganic and organic soil constituents, but also on the nature and characteristics of the elements involved as well as on their competition for sorption sites. The Kd value of TEs is mainly affected by individual or competitive sorption systems. Generally, the sorption in competitive systems is lower than in mono-metal sorption systems. More strongly sorbed elements, such as Pb and Cu, are less affected by competition than mobile elements, such as Cd, Ni, and Zn. The sorption preference exhibited by soils for elements over others may be due to: (i) the hydrolysis constant, (ii) the atomic weight, (iii) the ionic radius, and subsequently the hydrated radius, and (iv) its Misono softness value. Moreover, element concentrations in the test solution mainly affect the Kd values. Mostly, values of Kd decrease as the concentration of the included cation increases in the test solution. Additionally, the Kd of TEs is controlled by the sorption characteristics of soils, such as pH, clay minerals, soil organic matter, Fe and Mn oxides, and calcium carbonate. However, more research is required to verify the practical utilization of studying Kd of TEs in soils as a reliable indicator for assessing the remediation process of toxic metals in soils and waters. © 2013 Elsevier B.V. All rights reserved.

  17. Sorption-desorption of imidacloprid onto a lacustrine Egyptian soil and its clay and humic acid fractions.

    Science.gov (United States)

    Kandil, Mahrous M; El-Aswad, Ahmed F; Koskinen, William C

    2015-01-01

    Sorption-desorption of the insecticide imidacloprid 1-[(6-chloro-3-pyridinyl)-methyl]-N-nitro-2-imidazolidinimine onto a lacustrine sandy clay loam Egyptian soil and its clay and humic acid (HA) fractions was investigated in 24-h batch equilibrium experiments. Imidacloprid (IMDA) sorption-desorption isotherms onto the three sorbents were found to belong to a non-linear L-type and were best described by the Freundlich model. The value of the IMDA adsorption distribution coefficient, Kd(ads), varied according to its initial concentration and was ranged 40-84 for HA, 14-58 for clay and 1.85-4.15 for bulk soil. Freundlich sorption coefficient, Kf(ads), values were 63.0, 39.7 and 4.0 for HA, clay and bulk soil, respectively. The normalized soil Koc value for imidacloprid sorption was ∼800 indicating its slight mobility in soils. Nonlinear sorption isotherms were indicated by 1/n(ads) values imidacloprid sorption process with all tested sorbents. Gibbs free energy (ΔG) values indicated a spontaneous and physicosorption process for IMDA and a more favorable sorption to HA than clay and soil. In conclusion, although the humic acid fraction showed the highest capacity and affinity for imidacloprid sorption, the clay fraction contributed to approximately 95% of soil-sorbed insecticide. Clay and humic acid fractions were found to be the major two factors controlling IMDA sorption in soils. The slight mobility of IMDA in soils and the hysteresis phenomenon associated with the irreversibility of its sorption onto, mainly, clay and organic matter of soils make its leachability unlikely to occur.

  18. Influence of soil pH on the sorption of ionizable chemicals: modeling advances.

    Science.gov (United States)

    Franco, Antonio; Fu, Wenjing; Trapp, Stefan

    2009-03-01

    The soil-water distribution coefficient of ionizable chemicals (K(d)) depends on the soil acidity, mainly because the pH governs speciation. Using pH-specific K(d) values normalized to organic carbon (K(OC)) from the literature, a method was developed to estimate the K(OC) of monovalent organic acids and bases. The regression considers pH-dependent speciation and species-specific partition coefficients, calculated from the dissociation constant (pK(a)) and the octanol-water partition coefficient of the neutral molecule (log P(n)). Probably because of the lower pH near the organic colloid-water interface, the optimal pH to model dissociation was lower than the bulk soil pH. The knowledge of the soil pH allows calculation of the fractions of neutral and ionic molecules in the system, thus improving the existing regression for acids. The same approach was not successful with bases, for which the impact of pH on the total sorption is contrasting. In fact, the shortcomings of the model assumptions affect the predictive power for acids and for bases differently. We evaluated accuracy and limitations of the regressions for their use in the environmental fate assessment of ionizable chemicals.

  19. Research on sorption behavior of radionuclides under shallow land environment. Mechanism and standard methodologies for measurement of distribution coefficients of radionuclides

    International Nuclear Information System (INIS)

    Sakamoto, Yoshiaki; Tanaka, Tadao; Takebe, Shinichi; Nagao, Seiya; Ogawa, Hiromichi; Komiya, Tomokazu; Hagiwara, Shigeru

    2001-01-01

    This study consists of two categories' research works. One is research on sorption mechanism of radionuclides with long half-life, which are Technetium-99, TRU elements and U series radionuclides, on soil and rocks, including a development of database of distribution coefficients of radionuclides. The database on the distribution coefficients of radionuclides with information about measurement conditions, such as shaking method, soil characteristics and solution composition, has been already opened to the public (JAERI-DATABASE 20001003). Another study is investigation on a standard methodology of the distribution coefficient of radionuclide on soils, rocks and engineering materials in Japan. (author)

  20. Sorption and desorption kinetics of diuron, fluometuron, prometryn and pyrithiobac sodium in soils.

    Science.gov (United States)

    Baskaran, S; Kennedy, I R

    1999-11-01

    The sorption and desorption characteristics of four herbicides (diuron, fluometuron, prometryn and pyrithiobac-sodium) in three different cotton growing soils of Australia was investigated. Kinetics and equilibrium sorption and desorption isotherms were determined using the batch equilibrium technique. Sorption was rapid (> 80% in 2 h) and sorption equilibrium was achieved within a short period of time (ca 4 h) for all herbicides. Sorption isotherms of the four herbicides were described by Freundlich equation with an r2 value > 0.98. The herbicide sorption as measured by the distribution coefficient (Kd) values ranged from 3.24 to 5.71 L/kg for diuron, 0.44 to 1.13 L/kg for fluometuron, 1.78 to 6.04 L/kg for prometryn and 0.22 to 0.59 L/kg for pyrithiobac-sodium. Sorption of herbicides was higher in the Moree soil than in Narrabri and Wee Waa soils. When the Kd values were normalised to organic carbon content of the soils (Koc), it suggested that the affinity of the herbicides to the organic carbon increased in the order: pyrithiobac-sodium diuron. The desorption isotherms were also adequately described by the Freundlich equation. For desorption, all herbicides exhibited hysteresis and the hysteresis was stronger for highly sorbed herbicides (diuron and prometryn) than the weakly sorbed herbicides (fluometuron and pyrithiobac-sodium). Hysteresis was also quantified as the percentage of sorbed herbicides which is not released during the desorption step (omega = [nad/nde - 1] x 100). Soil type and initial concentration had significant effect on omega. The effect of sorption and desorption properties of these four herbicides on the off-site transport to contaminate surface and groundwater are also discussed in this paper.

  1. Sorption of phenanthrene in agricultural soils

    DEFF Research Database (Denmark)

    Soares, António Carlos Alves; Minh, Luong Nhat; Vendelboe, Anders Lindblad

    Polycyclic aromatic hydrocarbons (PAH) are among the major contaminants in the terrestrial environment. The background level in normal agricultural land has increased for many years and it is expected to further increase in the future. Because of the very low water solubility and high Kow values......, KD for more than one hundred Danish and European agricultural top and sub soils (122 topsoils and 28 subsoils) as well as the normalized distribution coefficient of the organic carbon content (KOC), through single point isotherm measurements. Possible effect of clay-complexed organic carbon...... models of Abdul et al. and Karickhoff et al. These two models were documented useful to predict maximum and minimum Koc for agricultural topsoils, for example in regard to predicting long-term PAH leaching from cultivated areas. Furthermore, we suggest a new Koc model in between Abdul and Karickhoff...

  2. The novel chloroplast outer membrane kinase KOC1 is a required component of the plastid protein import machinery.

    Science.gov (United States)

    Zufferey, Mónica; Montandon, Cyrille; Douet, Véronique; Demarsy, Emilie; Agne, Birgit; Baginsky, Sacha; Kessler, Felix

    2017-04-28

    The biogenesis and maintenance of cell organelles such as mitochondria and chloroplasts require the import of many proteins from the cytosol, a process that is controlled by phosphorylation. In the case of chloroplasts, the import of hundreds of different proteins depends on translocons at the outer and inner chloroplast membrane (TOC and TIC, respectively) complexes. The essential protein TOC159 functions thereby as an import receptor. It has an N-terminal acidic (A-) domain that extends into the cytosol, controls receptor specificity, and is highly phosphorylated in vivo However, kinases that phosphorylate the TOC159 A-domain to enable protein import have remained elusive. Here, using co-purification with TOC159 from Arabidopsis , we discovered a novel component of the chloroplast import machinery, the regulatory kinase at the outer chloroplast membrane 1 (KOC1). We found that KOC1 is an integral membrane protein facing the cytosol and stably associates with TOC. Moreover, KOC1 phosphorylated the A-domain of TOC159 in vitro , and in mutant koc1 chloroplasts, preprotein import efficiency was diminished. koc1 Arabidopsis seedlings had reduced survival rates after transfer from the dark to the light in which protein import into plastids is required to rapidly complete chloroplast biogenesis. In summary, our data indicate that KOC1 is a functional component of the TOC machinery that phosphorylates import receptors, supports preprotein import, and contributes to efficient chloroplast biogenesis. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  3. Measurement method of the distribution coefficient on the sorption process. Basic procedure of the method relevant to the barrier materials used for the deep geological disposal: 2006

    International Nuclear Information System (INIS)

    2006-08-01

    This standard was approved by Atomic Energy Society of Japan after deliberation of the Subcommittee on the Radioactive Waste Management, the Nuclear Cycle Technical Committee and the Standard Committee, and after obtaining about 600 comments from specialists of about 30 persons. This document defines the basic measurement procedure of the distribution coefficient (hereafter referred as Kd) to judge the reliability, reproducibility and applications and to provide the requirements for inter-comparison of Kd for a variety of barrier materials used for deep geological disposal of radioactive wastes. The basic measurement procedure of Kd is standardized, following the preceded standard, 'Measurement Method of the Distribution Coefficient on the Sorption Process - Basic Procedure of Batch Method Relevant to the Barrier Materials Used for the Shallow Land Disposal: 2002 (hereafter referred as Standard for the Shallow Land Disposal)', and considering recent progress after its publication and specific issues to the deep geological disposal. (J.P.N.)

  4. Sorption-desorption processes of radioisotopes with solid materials from liquid releases and atmosphere deposits. The distribution coefficient (Ksub(d)), its uses, limitations, and practical applications

    International Nuclear Information System (INIS)

    Saas, Arsene

    1979-03-01

    The various sorption-desorption processes of radionuclides with environmental materials are presented. The parameters governing the distribution coefficient are reviewed in the light of various examples. The factors affecting equilibria between the different phases are: reaction time, concentration of the solid phase, water quality, salinity, competition between ions, concentration of radioisotopes or stable isotopes, pH of the mobile phase, particle diameter, chemical form of the radioisotopes, nature of the solid phase, temperature. The effects of the biological parameters on the distribution coefficient are discussed. Biological processes affect the main chemical transformations: mineralization, insolubilization, oxidation-reduction, complexation, ... The importance of these processes is demonstrated by a number of examples in various media. Finally, the practical use of Ksub(d) in the assessment of the environmental impact of radioactive releases is developed, with special emphasis on the limits of its use in siting studies and its essential interest in specifying pathways and capacity of a river system [fr

  5. Contribution of coated humic acids calculated through their surface coverage on nano iron oxides for ofloxacin and norfloxacin sorption.

    Science.gov (United States)

    Peng, Hongbo; Liang, Ni; Li, Hao; Chen, Fangyuan; Zhang, Di; Pan, Bo; Xing, Baoshan

    2015-09-01

    Sorption of organic contaminants on organo-mineral complexes has been investigated extensively, but the sorption contribution of mineral particles was not properly addressed before calculating KOC, especially for ionic organic contaminants. We measured the surface coverage of a humic acid (HA) on nano iron oxides (n-Fe2O3) in a series of synthesized organo-mineral complexes. The contribution of the coated HA to ofloxacin (OFL) and norfloxacin (NOR) sorption in HA-n-Fe2O3 complexes was over 80% of the total sorption with the surface coverage of 36% and fOC of 1.6%. All the coated HA showed higher sorption to NOR and OFL in comparison to the original HA, suggesting HA fractionation and/or physical re-conformation during organo-mineral complex formation. The decreased KOC with multilayer coating may suggest the importance of site-specific interactions for OFL sorption, while the increased KOC with multilayer coating may suggest the importance of partitioning in hydrophobic region for NOR sorption. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Sorption by cation exchange

    International Nuclear Information System (INIS)

    Bradbury, M.H.; Baeyens, B.

    1994-04-01

    A procedure for introducing exchange into geochemical/surface complexation codes is described. Beginning with selectivity coefficients, K c , defined in terms of equivalent fractional ion occupancies, a general expression for the molar based exchange code input parameters, K ex , is derived. In natural systems the uptake of nuclides onto complex sorbents often occurs by more than one mechanism. The incorporation of cation exchange and surface complexation into a geochemical code therefore enables sorption by both mechanisms to be calculated simultaneously. The code and model concepts are tested against sets of experimental data from widely different sorption studies. A proposal is made to set up a data base of selectivity coefficients. Such a data base would form part of a more general one consisting of sorption mechanism specific parameters to be used in conjunction with geochemical/sorption codes to model and predict sorption. (author) 6 figs., 6 tabs., 26 refs

  7. Sorption, desorption and leaching potential of sulfonylurea herbicides in Argentinean soils.

    Science.gov (United States)

    Azcarate, Mariela P; Montoya, Jorgelina C; Koskinen, William C

    2015-01-01

    The sulfonylurea (SUs) herbicides are used to control broadleaf weeds and some grasses in a variety of crops. They have become popular because of their low application rates, low mammalian toxicity and an outstanding herbicidal activity. Sorption is a major process influencing the fate of pesticides in soil. The objective of this study was to characterize sorption-desorption of four sulfonylurea herbicides: metsulfuron-methyl (methyl 2-[(4-methoxy-6-methyl-1,3,5-triazin-2-yl)carbamoylsulfamoyl)]benzoate), sulfometuron-methyl (methyl 2-[(4,6-dimethylpyrimidin-2-yl)carbamoylsulfamoyl]benzoate), rimsulfuron (1-(4,6-dimethoxypyrimidin-2-yl)-3-(3-ethylsulfonyl-2-pyridylsulfonyl)urea) and nicosulfuron (2-[(4,6-dimethoxypyrimidin-2-yl)carbamoylsulfamoyl]-N,N-dimethylnicotinamide) from different soil horizons of different landscape positions. Sorption was studied in the laboratory by batch equilibration method. Sorption coefficients (K(d-SE)) showed that rimsulfuron (K(d-SE) = 1.18 to 2.08 L kg(-1)) and nicosulfuron (K(d-SE) = 0.02 to 0.47 L kg(-1)) were more highly sorbed than metsulfuron-methyl (K(d-SE) = 0.00 to 0.05 L kg(-1)) and sulfometuron-methyl (K(d-SE) = 0.00 to 0.05 L kg(-1)). Sorption coefficients (K(d-SE)) were correlated with pH and organic carbon content. All four herbicides exhibited desorption hysteresis where the desorption coefficients (K(d-D)) > K(d-SE). To estimate the leaching potential, K(oc) and ground-water ubiquity score (GUS) were used to calculate the half-life (t1/2) required to be classified as "leacher" or "nonleacher". According to the results, rimsulfuron and nicosulfuron herbicides would be classified as leachers, but factors such as landscape position, soil depth and the rate of decomposition in surface and subsurface soils could change the classification. In contrast, these factors do not affect classification of sulfometuron-methyl and metsulfuron-methyl; they would rank as leachers.

  8. Carbon Tetrachloride Partition Coefficients Measured by Aqueous Sorption to Hanford Sediments from Operable Units 200-UP-1 and 200-ZP-1

    International Nuclear Information System (INIS)

    Wellman, Dawn M.; Riley, Robert G.; Cordova, Elsa A.; Parker, Kent E.; Mitroshkov, Alexandre V.

    2007-01-01

    Kd values obtained on sediment samples from 200-UP-1 and 10-ZP-1 contribute to a larger Kd database that exists for other Hanford sediments, and contains significant desorption data for CCl4. Adsorption results presented here validate the use of a linear adsorption isotherm (Kd) to predict short contact time CCl4 adsorption to sediments in 200-UP-1 groundwater plume for a distinct ranges in CCl4 concentration. However, this does not imply that values of Kd will be constant if the groundwater chemical composition at 200-UP-1 changes with space or time. Additionally, results presented here suggest the potential significance of slower intraparticle diffusion on the long-term fate of CCl4 within the subsurface Hanford environment. Such behavior could afford prolonged desorption of CCl4 and serve as a long-term source of contaminant CCl4 to the aquifer. Further evaluation of possible bimodal sorption behavior for CCl4 and the mechanism of CCl4 sequestration should be the subject of future investigations to provide a thorough, mechanistic understanding of the retention and long-term fate of CCl4. Comparison of previous data with new results (e.g., from this study) will allow inferences to be made on how the 200-UP-1 Kd values for CCl4 may compare with sediments from other Hanford locations. This site-specific sorption data, when complemented by the chemical, geologic, mineralogic, hydrologic, and physical characterization data that are also being collected (see Sampling and Analysis Plan for the 200-UP-1 Groundwater Monitoring Well Network, DOE 2002) can be used to develop a robust, scientifically defensible data base to allow risk predictions to be generated and to aid in future remediation decisions for the 200-UP-1 and 200-ZP-1 operable units

  9. Sorption mechanisms and sorption models

    International Nuclear Information System (INIS)

    Fedoroff, M.; Lefevre, G.; Duc, M.; Neskovic, C.; Milonjic, S.

    2004-01-01

    Sorption at the solid-liquid interfaces play a major role in many phenomena and technologies: chemical separations, catalysis, biological processes, transport of toxic and radioactive species in surface and underground waters. The long term safety of radioactive waste repositories is based on artificial and natural barriers, intended to sorb radionuclides after the moment when the storage matrixes and containers will be corroded. Predictions on the efficiency of sorption for more than 10 6 years have to be done in order to demonstrate the safety of such depositories, what is a goal never encountered in the history of sciences and technology. For all these purposes, and, especially for the long term prediction, acquiring of sorption data constitutes only a first step of studies. Modeling based on a very good knowledge of sorption mechanisms is needed. In this review, we shall examine the main approaches and models used to quantify sorption processes, including results taken from the literature and from our own studies. We shall compare sorption models and examine their adequacy with sorption mechanisms. The cited references are only a few examples of the numerous articles published in that field. (orig.)

  10. Molecular simulation of polycyclic aromatic hydrocarbon sorption to black carbon

    NARCIS (Netherlands)

    Haftka, J.J.H.; Parsons, J.R.; Govers, H.A.J.

    2009-01-01

    Strong sorption of hydrophobic organic contaminants to soot or black carbon (BC) is an important environmental process limiting the bioremediation potential of contaminated soils and sediments. Reliable methods to predict BC sorption coefficients for organic contaminants are therefore required. A

  11. Prediction and validation of diffusion coefficients in a model drug delivery system using microsecond atomistic molecular dynamics simulation and vapour sorption analysis.

    Science.gov (United States)

    Forrey, Christopher; Saylor, David M; Silverstein, Joshua S; Douglas, Jack F; Davis, Eric M; Elabd, Yossef A

    2014-10-14

    Diffusion of small to medium sized molecules in polymeric medical device materials underlies a broad range of public health concerns related to unintended leaching from or uptake into implantable medical devices. However, obtaining accurate diffusion coefficients for such systems at physiological temperature represents a formidable challenge, both experimentally and computationally. While molecular dynamics simulation has been used to accurately predict the diffusion coefficients, D, of a handful of gases in various polymers, this success has not been extended to molecules larger than gases, e.g., condensable vapours, liquids, and drugs. We present atomistic molecular dynamics simulation predictions of diffusion in a model drug eluting system that represent a dramatic improvement in accuracy compared to previous simulation predictions for comparable systems. We find that, for simulations of insufficient duration, sub-diffusive dynamics can lead to dramatic over-prediction of D. We present useful metrics for monitoring the extent of sub-diffusive dynamics and explore how these metrics correlate to error in D. We also identify a relationship between diffusion and fast dynamics in our system, which may serve as a means to more rapidly predict diffusion in slowly diffusing systems. Our work provides important precedent and essential insights for utilizing atomistic molecular dynamics simulations to predict diffusion coefficients of small to medium sized molecules in condensed soft matter systems.

  12. Effects of Aging Quartz Sand and Hanford Site Sediment with Sodium Hydroxide on Radionuclide Sorption Coefficients and Sediment Physical and Hydrologic Properties: Final Report for Subtask 2a

    Energy Technology Data Exchange (ETDEWEB)

    DI Kaplan; JC Ritter; KE Parker

    1998-12-04

    Column and batch experiments were conducted in fiscal year 1998 at Pacific Northwest National Laboratory to evaluate the effect of varying concentrations of NaOH on the sorptive, physical, and hydraulic properties of two media, a quartz sand and a composite subsurface sediment from the 200-East Area of the Hanford Site. The NaOH solutions were used as a simplified effluent from a low-activity glass waste form. These experiments were conducted over a limited (O-to 10-month) contact time, with respect to the 10,000-to 100,000-year scenarios described in the Immobilized Low-Activity Waste- Performance Assessment (ILAW-PA). Wheq these two solids were put in contact with the NaOH solutions, dissolution was evident by a substantial increase in dissolved Si concentrations in the leachates. Incremental increases in NaOH con- centrations, resulted in corresponding increases in Si concentrations. A number of physical and hydraulic properties also changed as the NaOH concentrations were changed. It was observed that quartz sand was less reactive than the composite sediment. Further, moisture- retention measurements were made on the quartz sand and composite sedimen$ which showed that the NaOH-treated solids retained more water than the non-NaOH-treated solids. Because the other chemical, physical, and hydraulic measurements did not change dramatically after the high-NaOH treatments, the greater moisture retention of the high-NaOH treatments was attributed to a "salt effect" and not to the formation of small particles during the dissolution (weathering). The distribution coefficients (IQ) for Cs and Sr were measured on the NaOH-treated sediments, with decreases from -3,000 to 1,000 and 1,300 to 300 mL/g noted, respectively, at the 0.01-to 1.O-M NaOH levels. There was no apparent trend for the Sr & values with contact time. The lack of such a trend sug- gests that dissolution of sediment particles is not controlling the drop in IQ rather, it is the competition of the added Na

  13. Phenanthrene sorption on biochar-amended soils

    DEFF Research Database (Denmark)

    Kahawaththa Gamage, Inoka Damayanthi Kumari; Moldrup, Per; Paradelo Pérez, Marcos

    2014-01-01

    on their influences on the sorption of environmental contaminants. In a field-based study at two experimental sites in Denmark, we investigated the effect of birch wood-derived biochar (Skogans kol) on the sorption of phenanthrene in soils with different properties. The soil sorption coefficient, Kd (L kg-1......), of phenanthrene was measured on sandy loam and loamy sand soils which have received from zero up to 100 t ha-1 of biochar. Results show that birch wood biochar had a higher Kd compared to soils. Furthermore, the application of birch wood biochar enhanced the sorption of phenanthrene in agricultural soils...... carbon, while it negatively correlated with clay content. The results also revealed that biochar-mineral interactions play an important role in the sorption of phenanthrene in biochar-amended soil....

  14. Cobalt sorption onto Savannah River Plant soils

    International Nuclear Information System (INIS)

    Hoeffner, S.L.

    1985-06-01

    A laboratory study of cobalt-60 sorption was conducted using Savannah River Plant soil and groundwater from the low-level waste burial ground. Systematic variation of soil and water composition indicates that cobalt sorption is most strongly a function of pH. Over a pH range of 2 to 9, the distribution coefficient ranged from 2 to more than 10,000 mL/g. Changes in clay content and in K + , Ca 2+ , or Mg 2+ concentrations influence cobalt sorption indirectly through the slight pH changes which result. The ions Na + , Cl - , and NO 3 - have no effect on cobalt sorption. Ferrous ion, added to groundwater to simulate the condition of water at the bottom of the waste trenches, accounts for part of the decrease in cobalt sorption observed with trench waters. 17 refs., 3 figs., 4 tabs

  15. Influence of soil pH on the sorption of ionizable chemicals

    DEFF Research Database (Denmark)

    Franco, Antonio; Fu, Wenjing; Trapp, Stefan

    2009-01-01

    , the optimal pH to model dissociation was lower than the bulk soil pH. The knowledge of the soil pH allows calculation of the fractions of neutral and ionic molecules in the system, thus improving the existing regression for acids. The same approach was not successful with bases, for which the impact of p......The soil-water distribution coefficient of ionizable chemicals (K-d) depends on the soil acidity, mainly because the pH governs speciation. Using pH-specific K-d values normalized to organic carbon (K-OC) from the literature, a method was developed to estimate the K-OC of monovalent organic acids...

  16. Sorption of Heterocyclic Organic Compounds to Multiwalled Carbon Nanotubes.

    Science.gov (United States)

    Metzelder, Florian; Funck, Matin; Schmidt, Torsten C

    2018-01-16

    Sorption is an important natural and technical process. Sorption coefficients are typically determined in batch experiments, but this may be challenging for weakly sorbing compounds. An alternative method enabling analysis of those compounds is column chromatography. A column packed with the sorbent is used and sorption data are determined by relating sorbate retention to that of a nonretarded tracer. In this study, column chromatography was applied for the first time to study sorption of previously hardly investigated heterocyclic organic compounds to multiwalled carbon nanotubes (MWCNTs). Sorption data for these compounds are very limited in literature, and weak sorption is expected from predictions. Deuterium oxide was used as nonretarded tracer. Sorption isotherms were well described by the Freundlich model and data showed reasonable agreement with predicted values. Sorption was exothermic and physisorption was observed. H-bonding may contribute to overall sorption, which is supported by reduced sorption with increasing ionic strength due to blocking of functional groups. Lowering pH reduced sorption of ionizable compounds, due to electrostatic repulsion at pH 3 where sorbent as well as sorbates were positively charged. Overall, column chromatography was successfully used to study sorption of heterocyclic compounds to MWCNTs and could be applied for other carbon-based sorbents.

  17. PCB congener sorption to carbonaceous sediment components: Macroscopic comparison and characterization of sorption kinetics and mechanism

    International Nuclear Information System (INIS)

    Choi, Hyeok; Al-Abed, Souhail R.

    2009-01-01

    Sorption of polychlorinated biphenyls (PCBs) to sediment is a key process in determining their mobility, bioavailability, and chemical decomposition in aquatic environments. In order to examine the validity of currently used interpretation approaches for PCBs sorption, comparative results on 2-chlorobiphenyl sorption to carbonaceous components in sediments (activated carbon, carbon black, coal, soot, graphite, flyash, wood) were macroscopically correlated with the structural, morphological, crystallographic, and compositional properties of the carbonaceous components. Since the Freundlich sorption constant, K F (L kg -1 ) spanned several orders of magnitude, ranging from log K F of 6.13-5.27 for activated carbon, 5.04 for carbon black, 3.83 for coal to 3.08 for wood, organic carbon partitioning approach should be more specifically categorized, considering the various forms, nature and origins of organic carbon in sediment. Sorption rate constants and fraction parameters, which were numerically defined from empirical kinetic model with fast and slow sorption fractions, were closely related to the physicochemical properties of the carbonaceous components. Sorption interpretation approaches with a specific property and viewpoint, such as organic carbon partitioning, soot carbon distribution, or surface area correlation, did not properly explain the overall results on sorption capacity, fast and slow sorption kinetics, and partitioning coefficient. It is also important to emphasize the heterogeneous nature of sediment and the difficulties of encompassing the partitioning among its carbonaceous components.

  18. PCB congener sorption to carbonaceous sediment components: Macroscopic comparison and characterization of sorption kinetics and mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Hyeok [National Risk Management Research Laboratory, U.S. Environmental Protection Agency, 26 West Martin Luther King Drive, Cincinnati, OH 45268 (United States); Al-Abed, Souhail R., E-mail: al-abed.souhail@epa.gov [National Risk Management Research Laboratory, U.S. Environmental Protection Agency, 26 West Martin Luther King Drive, Cincinnati, OH 45268 (United States)

    2009-06-15

    Sorption of polychlorinated biphenyls (PCBs) to sediment is a key process in determining their mobility, bioavailability, and chemical decomposition in aquatic environments. In order to examine the validity of currently used interpretation approaches for PCBs sorption, comparative results on 2-chlorobiphenyl sorption to carbonaceous components in sediments (activated carbon, carbon black, coal, soot, graphite, flyash, wood) were macroscopically correlated with the structural, morphological, crystallographic, and compositional properties of the carbonaceous components. Since the Freundlich sorption constant, K{sub F} (L kg{sup -1}) spanned several orders of magnitude, ranging from log K{sub F} of 6.13-5.27 for activated carbon, 5.04 for carbon black, 3.83 for coal to 3.08 for wood, organic carbon partitioning approach should be more specifically categorized, considering the various forms, nature and origins of organic carbon in sediment. Sorption rate constants and fraction parameters, which were numerically defined from empirical kinetic model with fast and slow sorption fractions, were closely related to the physicochemical properties of the carbonaceous components. Sorption interpretation approaches with a specific property and viewpoint, such as organic carbon partitioning, soot carbon distribution, or surface area correlation, did not properly explain the overall results on sorption capacity, fast and slow sorption kinetics, and partitioning coefficient. It is also important to emphasize the heterogeneous nature of sediment and the difficulties of encompassing the partitioning among its carbonaceous components.

  19. Correlation of Benzene, 1,1,1-Trichloroethane, and Naphthalene Distribution Coefficients to the Characteristics of Aquifer Materials With Low Organic Carbon Content

    DEFF Research Database (Denmark)

    Larsen, Thomas; Kjeldsen, Peter; Christensen, Thomas Højlund

    1992-01-01

    area of the aquifer materials as a second regression parameter did not significantly improve the correlation. Estimated Koc values were up to 3 times higher than those predicted from regression equations based on the octanol-water partition coefficient. The reason for this is not known, but may...

  20. Sorption behaviour of radioactive technetium in soils

    International Nuclear Information System (INIS)

    Xia Deying

    1996-01-01

    The sorption behaviour of technetium in different soils has been studied by batch experiments under aerobic conditions. The soil samples have been taken to study the characteristics and to derive the pH-Eh values. In addition, the activated carbon and reduced iron powder have been selected as additives to the JAERI sand according to the former research work, so that the technetium sorption behaviour in the artificial soils can be studied under similar conditions. The experimental results show that all these soil samples except for the gluey soil have a very small distribution coefficient for Tc, while the artificial soils have a very large distribution coefficient for Tc. Besides, for artificial soils, the distribution coefficient (R d ) values will become larger and larger when more additive is added and more contact time is allowed. The physico-chemical fixation processes and possible sorption modes have been discussed as well

  1. Comparison of neptunium sorption results using batch and column techniques

    International Nuclear Information System (INIS)

    Triay, I.R.; Furlano, A.C.; Weaver, S.C.; Chipera, S.J.; Bish, D.L.

    1996-08-01

    We used crushed-rock columns to study the sorption retardation of neptunium by zeolitic, devitrified, and vitric tuffs typical of those at the site of the potential high-level nuclear waste repository at Yucca Mountain, Nevada. We used two sodium bicarbonate waters (groundwater from Well J-13 at the site and water prepared to simulate groundwater from Well UE-25p No. 1) under oxidizing conditions. It was found that values of the sorption distribution coefficient, Kd, obtained from these column experiments under flowing conditions, regardless of the water or the water velocity used, agreed well with those obtained earlier from batch sorption experiments under static conditions. The batch sorption distribution coefficient can be used to predict the arrival time for neptunium eluted through the columns. On the other hand, the elution curves showed dispersivity, which implies that neptunium sorption in these tuffs may be nonlinear, irreversible, or noninstantaneous. As a result, use of a batch sorption distribution coefficient to calculate neptunium transport through Yucca Mountain tuffs would yield conservative values for neptunium release from the site. We also noted that neptunium (present as the anionic neptunyl carbonate complex) never eluted prior to tritiated water, which implies that charge exclusion does not appear to exclude neptunium from the tuff pores. The column experiments corroborated the trends observed in batch sorption experiments: neptunium sorption onto devitrified and vitric tuffs is minimal and sorption onto zeolitic tuffs decreases as the amount of sodium and bicarbonate/carbonate in the water increases

  2. Sorption behavior of cesium onto bentonite colloid

    International Nuclear Information System (INIS)

    Iijima, Kazuki; Masuda, Tsuguya; Tomura, Tsutomu

    2004-01-01

    It is considered that bentonite colloid might be generated from bentonite which will be used as buffer material in geological disposal system, and can facilitate the migration of radionuclides by means of sorption. In order to examine this characteristic, sorption and desorption experiments of Cs onto bentonite colloid were carried out to obtain its distribution coefficient (Kd) and information on the reversibility of its sorption. In addition, particle size distribution and shape of colloid were investigated and their effect on the sorption behavior was discussed. Kds for Cs were around 20 m 3 /kg for sorption and 30 m 3 /kg for desorption, in which sorbed Cs was desorbed by 8.4x10 -4 mol/l of NaCl solution. These values did not show any dependencies on Cs concentration and duration of sorption and desorption. The first 20% of sorbed Cs was desorbed reversibly at least. Most of colloidal particles were larger than 200 nm and TEM micrographs showed they had only several sheets of the clay crystal. Obtained Kds for colloidal bentonite were larger than those for powdered bentonite. This can be caused by difference of competing ions in the solution, characteristics of contained smectite, or sorption site density. (author)

  3. The distribution coefficient concept and aspects on experimental distribution studies

    International Nuclear Information System (INIS)

    Allard, B.; Andersson, K.; Torstenfelt, B.

    1983-01-01

    Aspects on the distribution coefficient concept, sorption mechanisms and measurements of sorption phenomena are given. The distribution constant was shown to be pH-dependent. The temperature dependence of the sorption has been studied. The influence of the liquid/solid ratio has been studied for Cs and Sr. (G.B.)

  4. Sorption behavior of neptunium on bentonite -- Effect of calcium ion on the sorption

    International Nuclear Information System (INIS)

    Kozai, Naofumi; Ohnuki, Toshihiko; Muraoka, Susumu

    1995-01-01

    The sorption behavior of neptunium on bentonite was studied with batch type sorption and desorption experiments over a pH range of 2 to 8. A series of parallel studies using Na-smectite, Ca-smectite and admixtures of Na-smectite and calcite quantified the capacity of Ca 2+ (which occurs in bentonite as an exchangeable cation of smectite and as a component of calcite) to inhibit the sorption of neptunium. The distribution coefficient (K d ) of neptunium for bentonite was constant from pH 2 to 7, while for pure Na-smectite K d increased below pH 5 due to specific sorption of neptunium on Na-smectite. Specific sorption was defined as occurring when neptunium could be desorbed by a strong acid (1 M HCl) but was stable in the presence of 1 M KCl. It was found that the quantity of neptunium sorbed on Na-smectite was inversely proportional to the concentration of Ca 2+ in solution, an effect most pronounced at pH 2+ limits the specific sorption capacity of Na-smectite for neptunium. Similarly, in the mixture of Na-smectite and calcite, sufficient Ca 2+ was solubilized to depress neptunium sorption. This investigation demonstrates that Ca 2+ contained in bentonite as exchangeable cation and released from calcite reduces the specific sorption of neptunium

  5. Prediction of metal sorption in soils

    International Nuclear Information System (INIS)

    Westrich, Henry R.; Anderson, Harold L. Jr.; Arthur, Sara E.; Brady, Patrick V.; Cygan, Randall T.; Liang, Jianjie; Zhang, Pengchu; Yee, N.

    2000-01-01

    Radionuclide transport in soils and groundwaters is routinely calculated in performance assessment (PA) codes using simplified conceptual models for radionuclide sorption, such as the K D approach for linear and reversible sorption. Model inaccuracies are typically addressed by adding layers of conservativeness (e.g., very low K D 's), and often result in failed transport predictions or substantial increases in site cleanup costs. Realistic assessments of radionuclide transport over a wide range of environmental conditions can proceed only from accurate, mechanistic models of the sorption process. They have focused on the sorption mechanisms and partition coefficients for Cs + , Sr 2+ and Ba 2+ (analogue for Ra 2+ ) onto iron oxides and clay minerals using an integrated approach that includes computer simulations, sorption/desorption measurements, and synchrotron analyses of metal sorbed substrates under geochemically realistic conditions. Sorption of Ba 2+ and Sr 2+ onto smectite is strong, pH-independent, and fully reversible, suggesting that cation exchange at the interlayer basal sites controls the sorption process. Sr 2+ sorbs weakly onto geothite and quartz, and is pH-dependent. Sr 2+ sorption onto a mixture of smectite and goethite, however, is pH- and concentration dependent. The adsorption capacity of montmorillonite is higher than that of goethite, which may be attributed to the high specific surface area and reaction site density of clays. The presence of goethite also appears to control the extent of metal desorption. In-situ, extended X-ray absorption fine structure (EXAFS) spectroscopic measurements for montmorillonite and goethite show that the first shell of adsorbed Ba 2+ is coordinated by 6 oxygens. The second adsorption shell, however, varies with the mineral surface coverage of adsorbed Ba 2+ and the mineral substrate. This suggests that Ba 2+ adsorption on mineral surfaces involves more than one mechanism and that the stability of sorbed

  6. Effects of sorption behaviour on contaminant migration

    International Nuclear Information System (INIS)

    Melnyk, T.W.

    1985-11-01

    The effects of sorption behaviour on contaminant migration in groundwater systems are varied. Retardation of migration and dispersive effects can vary widely and contaminant concentration profiles can take a number of different shapes. This report examines the nature of some of these effects, especially those due to sorption behaviours that are dependent on the concentration of the contaminant in the groundwater. The effects are calculated using, in most cases, analytical solutions to the chemical equations imbedded in a simple reaction-cell or box-model transport algorithm. The hydrogeological parameters are held constant, and radioactive decay and hydrodynamic dispersion are excluded. A general discussion of the role of sorption equations in transport modelling is followed by presentation of migration results for a number of models of sorption behaviour varying from linear isotherms, Langmuir, Freundlich and ion-exchange isotherms, to precipitation reactions and multiple-site sorption reactions. The results are compared and general conclusions are drawn about the various migration behaviours calculated. The conclusions are that equilibrium sorption of trace contaminants can be modelled with linear isotherms (constant distribution coefficients or constant retardation factors) but the evaluation and extrapolation of the distribution coefficient are not easy. Nonlinear isotherms lead to unsymmetrical migration fronts. A comparison of Freundlich and linear isotherms is made. Sorption/desorption kinetic factors can be significant on the time scale of laboratory experiments and can cause large dispersive effects. Slow but important reactions can be missed altogether. Precipitation or mineralization behaviour cannot be modelled with constant distribution coefficients. Also, mineralization reactions can be kinetically slow even on the geological time scale. 89 refs

  7. Experimental study of strontium sorption on fissure filling material

    Energy Technology Data Exchange (ETDEWEB)

    Eriksen, T E; Cui, Daqing [Royal Institute of Technology, Stockholm (Sweden). Dept. of Chemistry

    1994-12-01

    We have carried out a comparative study of sorption and desorption of strontium in groundwater on separated magnetic and size fractions of fissure filling material taken from natural fissures in granitic rock. Complete reversibility of the sorption process was demonstrated by identical Freundlich isotherms, isotopic exchangeability and pH dependence of the distribution coefficients Rd. The sorption was found to be strongly pH dependent in the range 3-11. The pH effect can be accommodated in the sorption model by considering the surface areas and surface charges of the minerals in the fissure filling material. 20 refs, 9 figs, 3 tabs.

  8. Experimental study of strontium sorption on fissure filling material

    International Nuclear Information System (INIS)

    Eriksen, T.E.; Cui, Daqing

    1994-12-01

    We have carried out a comparative study of sorption and desorption of strontium in groundwater on separated magnetic and size fractions of fissure filling material taken from natural fissures in granitic rock. Complete reversibility of the sorption process was demonstrated by identical Freundlich isotherms, isotopic exchangeability and pH dependence of the distribution coefficients Rd. The sorption was found to be strongly pH dependent in the range 3-11. The pH effect can be accommodated in the sorption model by considering the surface areas and surface charges of the minerals in the fissure filling material. 20 refs, 9 figs, 3 tabs

  9. Improved understanding of tributyltin sorption on natural and biochar-amended sediments.

    Science.gov (United States)

    Xiao, Xiaoyu; Sheng, G Daniel; Qiu, Yuping

    2011-12-01

    A poor understanding of tributyltin (TBT) sorption on sediments has hindered an accurate evaluation of its environmental fate. The present study determined TBT sorption by a freshwater sediment (BH) and a coastal marine sediment (TZ) as influenced by pH, salinity, and biochar (BC) amendment into TZ. The isotherms were essentially linear, with K(OC) values in the range of 10(4) to 10(5) L/kg. Tributyltin sorption at pH 3.56 and 8.00 occurred mainly via partitioning. It reached maxima at pH equal to its pK(a) (=6.25) because of added ion exchange. A salinity increase from 5 to 35 practical salinity units enhanced TBT sorption at pH 3.56 and 8.00 on TZ by approximately 30% and on BH by approximately 80%, ascribed to the salting-out effect that reduced the solubilities of tributyltin hydroxide (TBTOH) and tributyltin chloride (TBTCl). At pH 6.25, the same salinity increase reduced TBT sorption on TZ by approximately 20% but enhanced TBT sorption on BH by approximately 35%. This was attributed to the enhancing role of salting out and the reducing role of metal competition for ion exchange. Tributyltin was two orders of magnitude more effectively sorbed by BC than by total organic carbon of TZ, mainly because of the high level of surface area of the BC. Although BC affinity for TBT may be significantly diminished when present in TZ, it was considered to be the primary contributor to TBT sorption from water. Biochar may thus be used to immobilize TBT in sediment for potential remediation. Copyright © 2011 SETAC.

  10. The NEA sorption data base (SDB)

    International Nuclear Information System (INIS)

    Ruegger, B.; Ticknor, K.

    1992-01-01

    The current NEA Sorption Data Base is developed to replace the former International Sorption Information Retrieval System (ISIRS) initiated at Pacific Northwest Laboratory and contains about 11,000 distribution coefficients with corresponding experimental condition parameters describing sorption of key nuclides for a large variety of solid and liquid phases. The SDB is designed to run on a micro-computer using the commercially available database software dBASE III Plus. For each recorded sorption experiment, the SDB provides a bibliographical reference, the most complete characterization of the solid and liquid phases available, a description of the experimental conditions and the distribution coefficient or retardation factor for each element studied. When available, parameters such as temperature, initial radionuclide concentration, pH, Eh, contact time, solid to solution ratio, sample origin, oxidation state and type of solution are included. The SDB provides information for a wide variety of rocks or geological materials, buffer backfill candidates, concretes/cements, elements (Am, Cs, Co, I, Np, Pu, Ra, Sr, Se, Tc, U and, to a lesser extent, Ag, Ba, C, Ce, Eu, Fe, Mn, Mo, Na, Nb, Ni, Pd, Pm, Ru, Sb, Sn, Y, Zn, and Zr), or radioisotopes. A compilation of sorption data like SDB provide a readily available source of data for radioactive waste repository performance assessments when site specific data are not available or essential, for example, during a site selection phase. 2 appendices

  11. Sorption of cesium and uranium to Feldspar

    International Nuclear Information System (INIS)

    Wijland, G.C.; Pennders, R.M.J.

    1990-07-01

    Within safety assessment studies, for nuclear waste disposal in deep geologic formations, calculation for the migration of radionuclides through the geosphere are often carried out with models taking sorption into account. In the past 8 years the insight grew that other physico-chemical processes, besides sorption, could affect migration behaviour. While the currently used transport models were being improved taking either linear or non-linear sorption into account, the coupling of geochemical and transport models came into scope. In spite of these developments models which are still based on the sorption theory are frequently applied in studying migration behaviour of radionuclides. This is caused by the necessity of making preliminary pronouncements, while coupled models are still in stage of development and thermodynamic data are very limited available. Therefore one has to obtain insight in the reliability of the models based on the sorption theory. within the sorption database there is a lack of knowledge about mineralogy, composition of the fluid and the experimental conditions underlying the data. Therefore the Expert Group on geochemical Modelling supported by the Finnish proposal in order to obtain insight in the possible deviation of the sorption coefficients that can be estimated from experiments performed with standard samples, fluid composition and experimental conditions. Nine laboratories from OECD membership countries took part in this intercalibration study. In the framework of the Dutch safety assessment studies the Dutch National Institute of Public health and Environmental protection (RIVM) has decided to participate in this exercise. In this report the results are presented of sorption experiments for cesium and natural Uranium to Feldspar. (H.W.). 4 refs.; 1 fig.; 7 tabs

  12. Yucca Mountain Project far-field sorption studies and data needs

    International Nuclear Information System (INIS)

    Meijer, A.

    1990-09-01

    Batch sorption experiments in which radionuclides dissolved in groundwaters from Yucca Mountain were sorbed onto samples of crushed tuff have resulted in a substantial database of sorption coefficients for radionuclides of interest to the repository program. Although this database has been useful in preliminary evaluations of Yucca Mountain as a potential site for a nuclear waste repository, the database has limitations that must be addressed before it can be used for performance assessment calculations in support of a license application for a waste repository. The purpose of this paper is to: review the applicability of simple (constant) sorption coefficients in transport calculations; review and evaluate alternative methods for the derivation of sorption coefficients; summarize and evaluate the present YMP sorption database to identify areas of data sufficiency and significant data gaps; summarize our current understanding of pertinent sorption mechanisms and associated kinetic parameters; evaluate the significance to the YMP of potential problems in the experimental determination and field application of sorption coefficients as enumerated by the NRC (Nuclear Regulatory Commission, 1987) in its technical position paper on sorption; formulate and evaluate strategies for the resolution of NRC concerns regarding experimental problems; and formulate a position on the sorption coefficient database and the level of understanding of sorption mechanisms likely to be required in the licensing application. 75 refs., 1 fig., 2 tabs

  13. Sorption of natural uranium by algerian bentonite

    International Nuclear Information System (INIS)

    Megouda, N.; Kadi, H.; Hamla, M.S.; Brahimi, H.

    2004-01-01

    Full text.Batch sorption experiments have been used to assess the sorption behaviour of uranium onto natural and drilling bentonites. The operating parameters (pH, aolis-liquid ratio, particle size, time and initial uranium concentration) influenced the rate of adsorption. The distribution coefficient (Kd) range values at equilibrium time are 45.95-1079.26 ml/g and 32.81-463053 ml/g for the drilling and natural bentonites respectively. The equilibrium isotherms show that the data correlate with both Freundlich and Langmuir models

  14. Sorption and desorption of diuron in Oxisol under biochar application

    Directory of Open Access Journals (Sweden)

    Fabiano André Petter

    Full Text Available ABSTRACT The objective of this study was to verify the kinetics of sorption and desorption of diuron in an Oxisol under application of biochar. The samples were collected in a field experiment conducted in randomized design blocks consisted of 2 base fertilization levels (0 and 400 kg∙ha−1 NPK 00-20-20 fertilizer formula and 3 doses of biochar (0, 8 and 16 Mg∙ha−1. In the evaluation of sorption and desorption, Batch Equilibrium method was used. The kinetics of sorption and desorption of diuron, total organic carbon, fulvic acid, humic acid and humin, pH and partition coefficient to organic carbon were evaluated. The Freundlich isotherm was adjusted appropriately to describe diuron sorption kinetics in all the studied treatments. The application of biochar provided increment in the sorption (Kf and reduction in the desorption of diuron in 64 and 44%, respectively. This effect is attributed to the biochar contribution to the total organic carbon and C-humin and of these to diuron through hydrophobic interactions and hydrogen bonds. The positive correlation between the partition coefficient to organic carbon and Kf confirms the importance of soil organic compartment in the sorption of diuron. There was no competition of NPK fertilizer for the same sorption site of diuron. The increase and reduction in sorption and desorption, respectively, show that the application of biochar is an important alternative for the remediation of soil leaching of diuron, especially in sandy soils.

  15. Influence of selected factors on strontium sorption on bentonites

    International Nuclear Information System (INIS)

    Galambos, M.; Kufcakova, J.; Rajec, P.

    2007-01-01

    Sorption on bentonite will play an important role in retarding the migration of radionuclides from a waste repository. Bentonite is a natural clay and one of the most promising candidates for use as a buffer material in the geological disposal systems for high-level nuclear waste. It is intended to isolate metal canisters with highly radioactive waste products from the surrounding rocks because of its ability to retard the movement of radionuclides by sorption. Bentonite is characterized by low permeability, water swelling capability and excellent sorption potential for cationic radionuclides. To correctly assess the sorption potential of radionuclides on bentonite is essential for the development of predictive migration models. The sorption of strontium on bentonite from different Slovak deposits - Jelsovy potok, Kopernica and Lieskovec has been investigated under various experimental conditions, such as contact time, sorbate concentrations, presence of complementary cation. Sorption was studied using the batch technique. The uptake of Sr was rapid and equilibrium was reached almost instantaneously. The instantaneous uptake may be due to adsorption and/or exchange of the metal with some ions on the surface of the adsorbent. The best sorption characteristics distinguish bentonite Kopernica, sorption capacity for Sr of the fraction under 45 mm is 0,48 mmol·g -1 for Sr. The highest values of distribution coefficient were reached for the bentonite Jelsovy potok. Radiation stability has been investigated, the higher sorption parameters were observed for the irradiated bentonites, which can be explained by the increase of specific surface of the bentonite samples. The presence of complementary cations depresses the sorption of Sr on bentonite. Cations Ca 2+ exhibit higher effect on cesium sorption than the Na 2+ ions. Results indicate that the sorption of Sr 2+ on bentonite will be affected by the presence of high concentrations of various salts in the waste water

  16. Co-contaminants and factors affecting the sorption behaviour of two sulfonamides in pasture soils

    International Nuclear Information System (INIS)

    Srinivasan, Prakash; Sarmah, Ajit K.; Manley-Harris, Merilyn

    2013-01-01

    We investigated the effect of soil pH, organic carbon, ionic strength and steroid hormones on the sorption of sulfamethoxazole (SMO) and sulfachloropyridazine (SCP) in three pastoral soils of New Zealand. A model linking sorbate speciation with species-specific sorption coefficients describing the pH dependence of the apparent sorption coefficients was used to derive the fraction of each species of SMO. All soils displayed a decrease in sorption when pH was increased, with SMO exhibiting the highest sorption at pH 2. The cationic form of SMO appeared to sorb more close to pH ≥ pK a1 and, when pH ≥ pK a2 (6.5, 7.5 and 8.5) the anionic species seems to dominate, however, its sorption affinity to all soils was low. SMO sorption was affected by ionic strengths and organic carbon content, while the presence of hormones showed only a subtle decrease in SCP sorption in a selected model pasture soil. -- Highlights: •The effect of OC content on sulfamethoxazole sorption is nullified by the pH effect. •Steroid hormone has a subtle influence on the sulfachloropyridazine sorption in pastoral soil. •Increased hormone concentrations decrease sulfachloropyridazine sorption in soils. -- Sorption affinity of SMO and SCP are strongly governed by multitude of factors, and variations in these factors can be significant when manure and fertilisers are added to soil

  17. Computer simulation of molecular sorption in zeolites

    International Nuclear Information System (INIS)

    Calmiano, Mark Daniel

    2001-01-01

    The work presented in this thesis encompasses the computer simulation of molecular sorption. In Chapter 1 we outline the aims and objectives of this work. Chapter 2 follows in which an introduction to sorption in zeolites is presented, with discussion of structure and properties of the main zeolites studied. Chapter 2 concludes with a description of the principles and theories of adsorption. In Chapter 3 we describe the methodology behind the work carried out in this thesis. In Chapter 4 we present our first computational study, that of the sorption of krypton in silicalite. We describe work carried out to investigate low energy sorption sites of krypton in silicalite where we observe krypton to preferentially sorb into straight and sinusoidal channels over channel intersections. We simulate single step type I adsorption isotherms and use molecular dynamics to study the diffusion of krypton and obtain division coefficients and the activation energy. We compare our results to previous experimental and computational studies where we show our work to be in good agreement. In Chapter 5 we present a systematic study of the sorption of oxygen and nitrogen in five lithium substituted zeolites using a transferable interatomic potential that we have developed from ab initio calculations. We show increased loading of nitrogen compared to oxygen in all five zeolites studied as expected and simulate adsorption isotherms, which we compare to experimental and simulated data in the literature. In Chapter 6 we present work on the sorption of ferrocene in the zeolite NaY. We show that a simulated, low energy sorption site for ferrocene is correctly located by comparing to X-ray powder diffraction results for this same system. The thesis concludes with some overall conclusions and discussion of opportunities for future work. (author)

  18. Sorption data bases and mechanistic sorption studies

    International Nuclear Information System (INIS)

    Bradbury, M.H.

    2000-01-01

    In common with many other countries with a nuclear programme, the Swiss concept for the disposal of radioactive waste is focused on deep burial in specially constructed repositories in geologically stable host rocks. Under such conditions, the most likely means whereby radionuclides might return to the biosphere involves their transport in slowly moving groundwater. The sorption of radionuclides by solid phases in the engineered barriers within the repository, and in the surrounding geological media, limits their release and retards their movement. Performance assessment studies for disposal concepts are carried out by Nagra, the National Cooperative for the Disposal of Radioactive Waste, in which various release scenarios are examined, and 'doses to man' calculated. The uptake of radionuclides by immobile phases is one of the pillars upon which the safety case rests. Hence, sorption databases are very important data sets for performance assessments. The methodology lying behind the construction of sorption databases, and some aspects of the supporting experimental work, are briefly described in this report. Flexible, long-term, focused research programmes are required to properly understand the radionuclide/rock/groundwater system, and this is an essential pre-requisite for producing robust state-of-the-art sorption databases. (author)

  19. Sorption data bases and mechanistic sorption studies

    Energy Technology Data Exchange (ETDEWEB)

    Bradbury, M.H

    2000-07-01

    In common with many other countries with a nuclear programme, the Swiss concept for the disposal of radioactive waste is focused on deep burial in specially constructed repositories in geologically stable host rocks. Under such conditions, the most likely means whereby radionuclides might return to the biosphere involves their transport in slowly moving groundwater. The sorption of radionuclides by solid phases in the engineered barriers within the repository, and in the surrounding geological media, limits their release and retards their movement. Performance assessment studies for disposal concepts are carried out by Nagra, the National Cooperative for the Disposal of Radioactive Waste, in which various release scenarios are examined, and 'doses to man' calculated. The uptake of radionuclides by immobile phases is one of the pillars upon which the safety case rests. Hence, sorption databases are very important data sets for performance assessments. The methodology lying behind the construction of sorption databases, and some aspects of the supporting experimental work, are briefly described in this report. Flexible, long-term, focused research programmes are required to properly understand the radionuclide/rock/groundwater system, and this is an essential pre-requisite for producing robust state-of-the-art sorption databases. (author)

  20. Moisture sorption of Thai red curry powder

    Directory of Open Access Journals (Sweden)

    Sudathip Inchuen

    2009-12-01

    Full Text Available Moisture sorption study was conducted on Thai red curry powder prepared by two different drying methods, viz. microwave and hot-air drying. Moisture sorption isotherms of the red curry powder at 30 C and water activity in the range of 0.113-0.970 were determined by a static gravimetric method. The isotherms exhibited Type III behaviour. The moisture sorption data were fitted to several sorption models and a non-linear regression analysis method was used to evaluate the constants of the sorption equations. The fit was evaluated using the coefficient of determination (R2, the reduced chi-square (2 and the root mean square error (RMSE. The GAB model followed by the Lewiski-3 model gave the best fit to the experimental data. The monolayer moisture content, taken as the safe minimum moisture level in the red curry powder, was determined using the BET equation and was found to range between 0.080 - 0.085 gram water per gram dry matter.

  1. Leaching and sorption of neonicotinoid insecticides and fungicides from seed coatings

    Science.gov (United States)

    Smalling, Kelly; Hladik, Michelle; Sanders, Corey; Kuivila, Kathryn

    2018-01-01

    Seed coatings are a treatment used on a variety of crops to improve production and offer protection against pests and fungal outbreaks. The leaching of the active ingredients associated with the seed coatings and the sorption to soil was evaluated under laboratory conditions using commercially available corn and soybean seeds to study the fate and transport of these pesticides under controlled conditions. The active ingredients (AI) included one neonicotinoid insecticide (thiamethoxam) and five fungicides (azoxystrobin, fludioxonil, metalaxyl, sedaxane thiabendazole). An aqueous leaching experiment was conducted with treated corn and soybean seeds. Leaching potential was a function of solubility and seed type. The leaching of fludioxonil, was dependent on seed type with a shorter time to equilibrium on the corn compared to the soybean seeds. Sorption experiments with the treated seeds and a solution of the AIs were conducted using three different soil types. Sorption behavior was a function of soil organic matter as well as seed type. For most AIs, a negative relationship was observed between the aqueous concentration and the log Koc. Sorption to all soils tested was limited for the hydrophilic pesticides thiamethoxam and metalaxyl. However, partitioning for the more hydrophobic fungicides was dependent on both seed type and soil properties. The mobility of fludioxonil in the sorption experiment varied by seed type indicating that the adjuvants associated with the seed coating could potentially play a role in the environmental fate of fludioxonil. This is the first study to assess, under laboratory conditions, the fate of pesticides associated with seed coatings using commercially available treated seeds. This information can be used to understand how alterations in agricultural practices (e.g., increasing use of seed treatments) can impact the exposure (concentration and duration) and potential effects of these chemicals to aquatic and terrestrial organisms.

  2. Sorption properties of wool

    Directory of Open Access Journals (Sweden)

    Radetić Maja M.

    2004-01-01

    Full Text Available Strict ecological legislation, especially in highly developed countries, imposed requirements for the purification of industrial effluents and the need for efficient oil clean up after sea and inland water spills. Although numerous processes have been developed, the application of sorbents is still one of the most efficient methods to remove heavy metal ions, dyes and crude oil from water. Recently, special attention was paid to sorbents based on natural fibres. A review of studies concerning the sorption properties of wool is presented in this paper. The presence of various functional groups on the wool fibre surface contributes to the efficient sorption of heavy metal ions and dyes. A hydrophobic, scaly surface and fibre crimp strongly influence the high sorption capacity of wool for oil. Wool has great sorption potential even as a recycled material. Accordingly, it can be used as a viable substitute to commercially available synthetic sorbents that show poor biodegradab ility.

  3. Column Chromatography To Obtain Organic Cation Sorption Isotherms.

    Science.gov (United States)

    Jolin, William C; Sullivan, James; Vasudevan, Dharni; MacKay, Allison A

    2016-08-02

    Column chromatography was evaluated as a method to obtain organic cation sorption isotherms for environmental solids while using the peak skewness to identify the linear range of the sorption isotherm. Custom packed HPLC columns and standard batch sorption techniques were used to intercompare sorption isotherms and solid-water sorption coefficients (Kd) for four organic cations (benzylamine, 2,4-dichlorobenzylamine, phenyltrimethylammonium, oxytetracycline) with two aluminosilicate clay minerals and one soil. A comparison of Freundlich isotherm parameters revealed isotherm linearity or nonlinearity was not significantly different between column chromatography and traditional batch experiments. Importantly, skewness (a metric of eluting peak symmetry) analysis of eluting peaks can establish isotherm linearity, thereby enabling a less labor intensive means to generate the extensive data sets of linear Kd values required for the development of predictive sorption models. Our findings clearly show that column chromatography can reproduce sorption measures from conventional batch experiments with the benefit of lower labor-intensity, faster analysis times, and allow for consistent sorption measures across laboratories with distinct chromatography instrumentation.

  4. Sorption of cesium in intact rock

    International Nuclear Information System (INIS)

    Puukko, E.

    2014-04-01

    The mass distribution coefficient K d is used in performance assessment (PA) to describe sorption of a radionuclide on rock. The R d is determined using crushed rock which causes uncertainty in converting the R d values to K d values for intact rock. This work describes a method to determine the equilibrium of sorption on intact rock. The rock types of the planned Olkiluoto waste disposal site were T-series mica gneiss (T-MGN), T-series tonalite granodiorite granite gneiss (T-TGG), P-series tonalite granodiorite granite gneiss (P-TGG) and pegmatitic granite (PGR). These rocks contain different amount of biotite which is the main sorbing mineral. The sorption of cesium on intact rock slices was studied by applying an electrical field to speed up migration of cesium into the rock. Cesium is in the solution as a noncomplex cation Cs + and it is sorbed by ion exchange. The tracer used in the experiments was 134 Cs. The experimental sorption on the intact rock is compared with values calculated using the in house cation exchange sorption model (HYRL model) in PHREEQC program. The observed sorption on T-MGN and T-TGG rocks was close to the calculated values. Two PGR samples were from a depth of 70 m and three samples were from a depth of 150 m. Cesium sorbed more than predicted on the two 70 m PGR samples. The sorption of Cs on the three 150 m PGR samples was small which was consistent with the calculations. The pegmatitic granite PGR has the smallest content of biotite of the four rock types. In the case of P-TGG rock the observed values of sorption were only half of the calculated values. Two kind of slices were cut from P-TGG drill core. The slices were against and to the direction of the foliation of the biotite rims. The sorption of cesium on P-TGG rock was same in both cases. The results indicated that there was no effect of the directions of the electric field and the foliation of biotite in the P-TGG rock. (orig.)

  5. Recent progress in sorption mechanisms and models

    International Nuclear Information System (INIS)

    Fedoroff, M.; Lefevre, G.

    2005-01-01

    Full text of publication follows: Sorption-desorption phenomena play an important role in the migration of radioactive species in surface and underground waters. In order to predict the transport of these species, we need a good knowledge of sorption processes and data, together with reliable models able to be included in transport calculation. Traditional approaches based on experimentally determined distribution coefficients (Kd) and sorption isotherms have a limited predictive capability, since they are very sensitive to the numerous parameters characterizing the solution and the solid. Models based on thermodynamic equilibria were developed to account for the influence these parameters: the ion exchange model and the surface complexation models (2-pK mono-site, 1-pK multi-site, with several different electrostatic models: CCM, DLM, BSM, TLM,...). Although these models are very useful, studies performed in recent years showed that they have important theoretical and experimental limitations, which result in the fact that we must be very careful when we use them for extrapolating sorption data to long term and to large natural systems. Among all problems which can be found are: the possibility to fit a set of experimental data with different models, sometimes bad adequacy with the real sorption processes, some theoretical limitations such as a rigorous definition of reference and standard states in surface equilibria, slow kinetics which prevent from equilibrium achievement, irreversibility, solubility and evolution of solid phases... Through the increase of the number of sensitive spectroscopic methods, we are now able to know more about sorption processes at the atomic scale. Models such as the 1-pK CD-MUSIC model can account for the influence of orientation of the faces of the solid. More and more examples of the influence of this orientation on the sorption properties are known. Calculations performed by 'ab initio' modeling is also useful to predict the

  6. Sorption and pertechnetate by salts of molybdophosphoric acid

    International Nuclear Information System (INIS)

    Suess, M.; Pfrepper, G.

    1983-01-01

    The sorption of pertechnetate on salts of molybdophosphoric acid from nitric acid and in the presence of electrolytes was investigated. Distribution coefficients from 10 to 100 ml/g were found. The sorption of pertechnetate can be increased by the addition of K + , NH 4 + , Rb + and Cs + salts. A saturation capacity of proportional 0,19 mmol/g ammonium phosphomolybdate was found from the adsorption isotherms. The formation of alkali metal pertechnetate associates in the sorbent phase is supposed. (orig.)

  7. Effect of Cosolutes on the Sorption of Phenanthrene onto Mineral Surface of River Sediments and Kaolinite

    Directory of Open Access Journals (Sweden)

    Yinghong Wu

    2014-01-01

    Full Text Available Sorption of phenanthrene onto the natural sediment with low organic carbon content (OC%, organic-free sediment, and kaolinite was investigated through isotherm experiments. Effects of cosolutes (pyrene, 4-n-nonyphenol (NP, and humic acid (HA on phenanthrene sorption were also studied by comparing apparent solid-water distribution coefficients (Kdapp of phenanthrene. Two addition sequences, including “cosolute added prior to phenanthrene” and “cosolute and phenanthrene added simultaneously,” were adopted. The Freundlich model fits phenanthrene sorption on all 3 sorbents well. The sorption coefficients on these sorbents were similar, suggesting that mineral surface plays an important role in the sorption of hydrophobic organic contaminants on low OC% sediments. Cosolutes could affect phenanthrene sorption on the sorbents, which depended on their properties, concentrations, and addition sequences. Pyrene inhibited phenanthrene sorption. Sorbed NP inhibited phenanthrene sorption at low levels and promoted sorption at high levels. Similar to NP, effect of HA on phenanthrene sorption onto the natural sediment depended on its concentrations, whereas, for the organic-free sediment and kaolinite, preloading of HA at high levels led to an enhancement in phenanthrene Kdapp while no obvious effect was observed at low HA levels; dissolved HA could inhibit phenanthrene sorption on the two sorbents.

  8. Radionuclide sorption studies on abyssal red clays

    International Nuclear Information System (INIS)

    Erickson, K.L.

    1979-01-01

    The radionuclide sorption properties of a widely distributed abyssal red clay are being experimentally investigated using batch equilibration techniques. This paper summarizes sorption equilibrium data obtained when 0.68 N NaCl solutions containing either Tc, U, Pu, Am or Cm were contacted with samples of the red clay and also summarizes some initial results from experiments designed to determine the relative selectivity of the clay for various nuclides. Under mildly oxidizing conditions, the sorption equilibrium distribution coefficients for technetium were essentially zero. At solution-phase nuclide concentrations on the order of 10 -6 M and less and at solution pH values of about 6.9, the distribution coefficients for plutonium were about 3 x 10 3 m1/gm and for uranium, americium, and curium were about 10 5 ml/gm or greater. However, at solution pH values of about 2.7, the distribution coefficients for each of the nuclides were greatly diminished. Initial experiments conducted in order to determine the relative selectivity of the clay for cesium, barium, and cerium, indicated that the silicate phases in the clay were selective for cesium over barium and cerium. These experiments also indicated that the hydrous oxide phases were selective for cerium over barium and for barium over cesium

  9. Sorption of niobium on boreal forest soil

    Energy Technology Data Exchange (ETDEWEB)

    Soederlund, Mervi; Hakanen, Martti; Lehto, Jukka [Helsinki Univ. (Finland). Lab. of Radiochemistry

    2015-07-01

    The sorption of niobium (Nb) was investigated on humus and mineral soil samples taken from various depths of a four-metre deep forest soil pit on Olkiluoto Island, southwestern Finland. Mass distribution coefficients, K{sub d}, were determined in batch sorption tests. The steady state of Nb sorption was observed in the mineral soil samples already after one week of equilibration, and sorption decreased with depth from a very high value of 185000 mL/g at 0.7 m to 54000 mL/g at 3.4 m. The reason behind this decrease is probably the tenfold reduction in the specific surface area of the soil at the same depth range. Distribution coefficients were clearly lower in the humus layer (1000 mL/g). The K{sub d} values determined in pure water at a pH range of 4.7-6.5 were at a high level (above 55000 mL/g), but decreased dramatically above pH 6.5, corresponding to the change in the major Nb species from the neutral Nb(OH){sub 5} to the low-sorbing anionic Nb(OH){sub 6}{sup -} and Nb(OH){sub 7}{sup 2-}. However, the K{sub d} values in the model soil solution were in the slightly alkaline range an order of magnitude higher than in pure water, which is probably caused by the formation of calcium niobate surface precipitate or electrostatic interaction between surface-sorbed calcium and solute Nb. Among nine soil constituent minerals kaolinite performed best in retaining Nb in both pure water and model soil solution at pH 8, whereas potassium feldspar showed the poorest sorption. The K{sub d} value for kaolinite was above 500000 mL/g in both solutions, while the respective potassium feldspar values were in the range of 120-220 mL/g.

  10. Metal sorption on kaolinite

    International Nuclear Information System (INIS)

    Westrich, H.R.; Brady, P.V.; Cygan, R.T.; Nagy, K.L.; Anderson, H.L.

    1997-01-01

    A key issue in performance assessment of low-level radioactive waste sites is predicting the transport and retardation of radionuclides through local soils under a variety of hydrologic and geochemical conditions. Improved transport codes should include a mechanistic model of radionuclide retardation. The authors have been investigating metal sorption (Cs + , Sr 2+ , and Ba 2+ ) on a simple clay mineral (kaolinite) to better understand the geochemical interactions of common soil minerals with contaminated groundwaters. These studies include detailed characterizations of kaolinite surfaces, experimental adsorption measurements, surface complexation modeling, and theoretical simulations of cation sorption. The aluminol edge (010) site has been identified as the most likely site for metal sorption on kaolinite in natural solutions. Relative metal binding strengths decrease from Ba 2+ to Sr 2+ to Cs + , with some portion sorbed on both kaolinite edges and basal surfaces. Some Cs + also appears to be irreversibly sorbed on both sites. Molecular dynamics simulations suggest that Cs + is sorbed at aluminol (010) edge sites as an inner-sphere complex and weakly sorbed as an outer-sphere complex on (001) basal surfaces. These results provide the basis to understand and predict metal sorption onto kaolinite, and a framework to characterize sorption processes on more complex clay minerals

  11. Radionuclide sorption database for Swiss safety assessment

    International Nuclear Information System (INIS)

    McKinley, I.G.; Hadermann, J.

    1984-10-01

    Recommended sorption data for use in transport models for a Swiss High-Level Waste repository are presented. The models used in 'Project Gewaehr 1985' assume linear sorption isotherms and require elemental partition coefficient (Kd) data. On the basis of a literature search 'realistic' Kd data for 22 elements have been selected for weathered crystalline rock and sediments in contact with a reducing groundwater and also sediments with a less reducing groundwater. In an appendix sorption data for 28 elements on bentonite backfill are given. These data are supplemented with 'conservative' estimates taken to represent minimum reasonable values. Available data are discussed for each element clearly exhibiting (i) the large gaps in knowledge, (ii) their unbalanced distribution between different elements and, hence, (iii) the need for further experiments in the laboratory, the field and analogue studies. An overview of the theoretical concepts of sorption, experimental methodology and data interpretation is given in order to put the values into context. General problem areas are identified. (Auth.)

  12. A mechanistic approach to the generation of sorption databases

    International Nuclear Information System (INIS)

    Bradbury, M.H.; Baeyens, B.

    1992-01-01

    Sorption of radionuclides in the near and far fields of an underground nuclear waste repository is one of the most important processes retarding their release to the environment. In the vast majority of cases sorption data have been presented in terms of empirical parameters such as distribution coefficients and isotherm equations. A consequence of this empirical methodology is that the sorption data are only strictly valid under the experimental conditions at which they were measured. Implicit in this approach is the need to generate large amounts of data and fitting parameters necessary for an empirical description of sorption under all realistically conceivable conditions which may arise in space and time along the migration pathway to Man. An alternative approach to the problem is to try to understand, and develop model descriptions of, underlying retention mechanisms and to identify those systems parameters which essentially determine the extent of sorption. The aim of this work is to see to what extent currently existing mechanistic models, together with their associated data, can be applied to predict sorption data from laboratory experiments on natural systems. This paper describes the current status of this work which is very much in an early stage of development. An example is given whereby model predictions are compared with laboratory results for the sorption of Np at trace concentrations under oxidizing conditions on a series of minerals relevant to granite formations. 31 refs., 11 figs., 5 tabs

  13. Diffusion and sorption properties of radionuclides in compacted bentonite

    Energy Technology Data Exchange (ETDEWEB)

    Yu Ji-Wei; Neretnieks, I. [Royal Inst. of Tech., Stockholm (Sweden). Dept. of Chemical Engineering and Technology

    1997-07-01

    In this report, recent studies on sorption and diffusion of radionuclides in compacted bentonite have been reviewed. The sorption distribution coefficient and diffusion coefficient data obtained from experiments in the literature have been compiled. Based on these experimental data and the report SKB-TR--91-16 (Brandberg and Skagius, 1991), this report proposes a set of sorption distribution coefficient and diffusion coefficient values for modelling purpose for safety analysis of nuclear waste repositories. The variability and uncertainty of the diffusivity data span somewhat more than an order or magnitude up and down. Most of the nuclides have an effective diffusivity in around 10{sup -10} m{sup 2}/s. Ion exclusion effects are observed for C, Cl and for Tc in oxidizing waters. Effective diffusivities are nearly tow orders of magnitude lower for these elements and of the order of 10{sup -12} m{sup 2}/s. Surface diffusion effects are found for Cs, Ni, Pa, Pb, Ra, Sn, Sr and Zr. Effective diffusivities for these elements are of the order of 10{sup -8} m{sup 2}/s. The surface diffusion effect should decrease in saline waters which is seen for Cs and Sr where there are data available. It is also deemed that Ra will have this effect because of its similarity with Sr. The other nuclides should also show this decrease but no data is available. Sorption and diffusion mechanisms in compacted bentonite are discussed in the report. In highly compacted bentonite, sorption and hence its distribution coefficient is not well defined, and a pore diffusion coefficient or a surface diffusion coefficient is not well defined either. Therefore, an apparent diffusion coefficient and a total concentration gradient should be more relevant in describing the diffusion process in compacted bentonite. 99 refs.

  14. QSAR models for predicting octanol/water and organic carbon/water partition coefficients of polychlorinated biphenyls.

    Science.gov (United States)

    Yu, S; Gao, S; Gan, Y; Zhang, Y; Ruan, X; Wang, Y; Yang, L; Shi, J

    2016-04-01

    Quantitative structure-property relationship modelling can be a valuable alternative method to replace or reduce experimental testing. In particular, some endpoints such as octanol-water (KOW) and organic carbon-water (KOC) partition coefficients of polychlorinated biphenyls (PCBs) are easier to predict and various models have been already developed. In this paper, two different methods, which are multiple linear regression based on the descriptors generated using Dragon software and hologram quantitative structure-activity relationships, were employed to predict suspended particulate matter (SPM) derived log KOC and generator column, shake flask and slow stirring method derived log KOW values of 209 PCBs. The predictive ability of the derived models was validated using a test set. The performances of all these models were compared with EPI Suite™ software. The results indicated that the proposed models were robust and satisfactory, and could provide feasible and promising tools for the rapid assessment of the SPM derived log KOC and generator column, shake flask and slow stirring method derived log KOW values of PCBs.

  15. Sorption of radon-222 to natural sediments

    International Nuclear Information System (INIS)

    Wong, C.S.; Chin, Y.P.; Gschwend, P.M.

    1992-01-01

    The sorption of radon to sediments was investigated, since this may affect the use of porewater radon profiles for estimating bed irrigation rates. Batch experiments showed that radon has an organic-carbon-normalized sediment-water partition coefficient (K oc , L kg oc -1 ) of 21.1 ± 2.9 for a Boston Harbor sediment, 25.3 ± 2.1 for a Charles River sediment, and 22.4 ± 2.6 for a Buzzards Bay sediment. These values are in close agreement with predictions using radon's octanol-water partition coefficient (K ow ), which was measured to be 32.4 ± 1.5. Temperature and ionic strength effects on K oc were estimated to be small. Given rapid sorption kinetics, the authors suggest that slurry stripping techniques used by many investigators to measure 222 Rn in sediment samples collect both sorbed and dissolved radon. Sorption effects were included in a transport model to obtain revised estimates of irrigation rates from existing literature profiles. Irrigation rates had to be increased over previously reported values in proportion to the sediment organic matter content

  16. Kinetic and equilibrium characteristics of sorption of saponin of Quillaja Saponaria Molina on chitosan

    Science.gov (United States)

    Mironenko, N. V.; Smuseva, S. O.; Brezhneva, T. A.; Selemenev, V. F.

    2016-12-01

    The equilibrium and kinetic curves of the sorption of saponin of Quillaja saponaria molina on chitosan were analyzed. The inner diffusion was found to be limiting, and its coefficients were calculated. It was found that the form of the curves of the sorption isotherms of saponin is determined by the competing processes of association in solution and absorption by chitosan.

  17. Sorption of actinides in granitic rock

    International Nuclear Information System (INIS)

    Allard, B

    1982-11-01

    The sorption of americium (III), neptunium(V) and plutonium on geologic media under oxic conditions has been measured by a batch technique. The aqueous phase was a synthetic groundwater or 4M NaCl solution. The solid phase was a pure mineral, representative of igneous rocks, or granite. Altogether 40 different minerals and rocks were used. The effects of pH and the ionic strength of the aqueous phase as well as of the cation exchange capacity and the surface/mass ratio of the solid sorbent are discussed. Empirical equations giving the distribution coefficient as a function of pH in the environmental pH-range 7-9 are suggested. Some observations and conclusions concerning sorption mechanisms are given. (author)

  18. Sorption of lanthanoids by polymer-supported diaza-18-crown-6

    International Nuclear Information System (INIS)

    Bel'tyukova, S.I.; Malinka, E.V.; Kravchenko, T.B.; Roska, A.S.; Zitsmanis, A.Kh.

    1990-01-01

    Sorption of thenoyltrifluoroacetonates of rare earths on polymeric sorbent (copolymer of styrene-divinylbenzene) containing the functional groups of macrocyclic polyether diazo-18-crown-6 is studied. Sorption capacity of a sorbent and sorption coefficients are calculated. It is shgown that Eu 3+ , Sm 3+ and Gd 3+ are sorbed most of all, and Ce 3+ , Pr 3+ , Yb 3+ , Lu 3+ - worst of all. Luminescence properties of the sorption europium adduct is studied. The Eu detection limit in the sorbent is 0.00005 μg/ml, Sm - 0.01 μg/ml

  19. Sorption of americium and neptunium by deep-sea sediments

    International Nuclear Information System (INIS)

    Higgo, J.J.W.; Rees, L.V.C.; Cronan, D.S.

    1983-01-01

    The sorption and desorption of americium and neptunium by a wide range of deep-sea sediments from natural sea water at 4 0 C has been studied using a carefully controlled batch technique. All the sediments studied should form an excellent barrier to the migration of americium since distribution coefficients were uniformly greater than 10 5 and the sorption-desorption reaction may not be reversible. The sorption of neptunium was reversible and, except for one red clay, the distribution coefficients were greater than 10 3 for all the sediments investigated. Nevertheless the migration of neptunium should also be effectively retarded by most deep-sea sediments even under relatively oxidizing conditions. The neptunium in solution remained in the V oxidation state throughout the experiments. Under the experimental conditions used colloidal americium was trapped by the sediment and solubility did not seem to be the controlling factor in the desorption of americium. (Auth.)

  20. An update of the sorption database. Correction and addition of published literature data

    International Nuclear Information System (INIS)

    Saito, Yoshihiko; Suyama, Tadahiro; Kitamura, Akira; Shibata, Masahiro; Sasamoto, Hiroshi; Ochs, Michael

    2007-07-01

    Japan Nuclear Cycle Development Institute (JNC) had developed the sorption database (JNC-SDB) which includes distribution coefficient (K d ) data of important radioactive elements for bentonite and rocks in order to define a dataset to evaluate the safety function of retardation by natural barrier and engineered barrier in the H12 report. Then, JNC added to the database the sorption data from 1998 to 2003 collected by literature survey. In this report, Japan Atomic Energy Agency (JAEA) has updated the sorption database: (1) JAEA has widely collected the sorption data in order to extend the sorption database. The JNC-SDB has been added the published data which are not registered in the sorption database so far. (2) For the convenience of users the JNC-SDB was partially improved such as the automatic graph function. (3) Moreover, errors during data input in the part of the JNC-SDB were corrected on the basis of reviewing data in the database according to the guideline; 'evaluating and categorizing the reliability of distribution coefficient values in the sorption database'. In this updated JNC-SDB, 3,205 sorption data for 23 elements, which are important for performance assessment were included. The frequency of K d for some elements was clearly shown by addition of the sorption data. (author)

  1. Technetium Sorption Media Review

    International Nuclear Information System (INIS)

    Duncan, J.B.; Kelly, S.E.; Robbins, R.A.; Adams, R.D.; Thorson, M.A.; Haass, C.C.

    2011-01-01

    This report presents information and references to aid in the selection of 99Tc sorption media for feasibility studies regarding the removal of 99Tc from Hanford's low activity waste. The report contains literature search material for sorption media (including ion exchange media) for the most tested media to date, including SuperLig 639, Reillex HPQ, TAM (Kruion), Purolite A520E and A530E, and Dowex 1X8. The U.S. Department of Energy (DOE), Office of River Protection (ORP) is responsible for management and completion of the River Protection Project (RPP) mission, which comprises both the Hanford Site tank farms and the Waste Treatment and Immobilization Plant (WTP). The RPP mission is to store, retrieve and treat Hanford's tank waste; store and dispose of treated wastes; and close the tank farm waste management areas and treatment facilities in a safe, environmentally compliant, cost-effective and energy-effective manner.

  2. TECHNETIUM SORPTION MEDIA REVIEW

    Energy Technology Data Exchange (ETDEWEB)

    DUNCAN JB; KELLY SE; ROBBINS RA; ADAMS RD; THORSON MA; HAASS CC

    2011-08-25

    This report presents information and references to aid in the selection of 99Tc sorption media for feasibility studies regarding the removal of 99Tc from Hanford's low activity waste. The report contains literature search material for sorption media (including ion exchange media) for the most tested media to date, including SuperLig 639, Reillex HPQ, TAM (Kruion), Purolite A520E and A530E, and Dowex 1X8. The U.S. Department of Energy (DOE), Office of River Protection (ORP) is responsible for management and completion of the River Protection Project (RPP) mission, which comprises both the Hanford Site tank farms and the Waste Treatment and Immobilization Plant (WTP). The RPP mission is to store, retrieve and treat Hanford's tank waste; store and dispose of treated wastes; and close the tank farm waste management areas and treatment facilities in a safe, environmentally compliant, cost-effective and energy-effective manner.

  3. Sorption of Molecular Oxygen by Metal-Ion Exchanger Nanocomposites

    Science.gov (United States)

    Krysanov, V. A.; Plotnikova, N. V.; Kravchenko, T. A.

    2018-03-01

    Kinetic features are studied of the chemisorption and reduction of molecular oxygen from water by metal-ion exchanger nanocomposites that differ in the nature of the dispersed metal and state of oxidation. In the Pd equilibrium sorption coefficient for oxygen dissolved in water ranges from 20 to 50, depending on the nature and oxidation state of the metal component.

  4. Sorption of strontium on bentonites from Slovak deposits

    International Nuclear Information System (INIS)

    Kufcakova, J.; Galambos, M.; Rajc, P.

    2005-01-01

    Sorption on bentonite from different Slovak deposits / Jelsovy potok, Kopernica and Lieskove has been investigated under various experimental conditions, such as contact time, pH, sorbate concentrations, presence of complementary cation. The sorption of strontium from aqueous solutions was investigated using a radiometric determination of distribution coefficient, Kd. The individual solutions were labelled with radiotracer. Radiation stability has been investigated, the higher sorption parameters were observed for the irradiated bentonites /tab.l/ , which can be explained by the increase of specific surface and change of solubility of the irradiated samples of bentonite. The presence of complementary cations, Na + , K + , NH 4 + , Ca 2+ , Mg 2+ and Ba 2+ depresses the sorption of Sr on bentonite. In the case of bentonite Kopernica the effectiveness in reducing the sorption of strontium by cations followed the order K + 4 + + 2+ 2+ 2+ . Results indicate that the sorption of Sr + on bentonite will be affected by the presence of high concentrations of various salts in the waste water effluents. (author)

  5. Sorption of actinides onto nanodiamonds

    Energy Technology Data Exchange (ETDEWEB)

    Buchatskaya, Yulia; Romanchuk, Anna; Yakovlev, Ruslan; Kulakova, Inna [Lomonosov Moscow State Univ., Moscow (Russian Federation). Dept. of Chemistry; Shiryaev, Andrei [Russian Academy of Sciences, Moscow (Russian Federation). Frumkin Institute of Physical Chemistry and Electrochemistry; Russian Academy of Sciences, Moscow (Russian Federation). Inst. of Geology of Ore Deposits, Petrography, Mineralogy and Geochemistry; Kalmykov, Stepan [Lomonosov Moscow State Univ., Moscow (Russian Federation). Dept. of Chemistry; Russian Academy of Sciences, Moscow (Russian Federation). Frumkin Institute of Physical Chemistry and Electrochemistry; Russian Academy of Sciences, Moscow (Russian Federation). Vernadsky Institute of Geochemistry and Analytical Chemistry

    2015-06-01

    Detonation nanodiamonds (ND) present a significant part of nanocarbons group, which could be produced on commercial scale by detonation of explosives in a closed chamber. Their unique properties of high surface area, low weight and radiation resistance make ND a prospective candidate for applications in sorption processes in radiochemistry. To study the influence of surface chemistry on sorption properties, apristine sample of ND was treated with acids and hydrogen. The surface chemistry of the samples was characterised by infrared spectroscopy, X-ray photoelectron spectroscopy and Boehm titration. The sorption properties of ND were tested fordifferent radionuclides. The sorption capacity of ND was shown to be higher than those of commonly used radionuclide sorbents like activated carbon and compariable to other members of nanocarbon group like graphene oxide and carbon nanotubes. The sorption properties were shown to be influenced by the presence of oxygen-containing groups on the surface of ND. This represents an opportunity to increase the sorption capacity of ND.

  6. Sorption of actinides onto nanodiamonds

    International Nuclear Information System (INIS)

    Buchatskaya, Yulia; Romanchuk, Anna; Yakovlev, Ruslan; Kulakova, Inna; Shiryaev, Andrei; Russian Academy of Sciences, Moscow; Kalmykov, Stepan; Russian Academy of Sciences, Moscow; Russian Academy of Sciences, Moscow

    2015-01-01

    Detonation nanodiamonds (ND) present a significant part of nanocarbons group, which could be produced on commercial scale by detonation of explosives in a closed chamber. Their unique properties of high surface area, low weight and radiation resistance make ND a prospective candidate for applications in sorption processes in radiochemistry. To study the influence of surface chemistry on sorption properties, apristine sample of ND was treated with acids and hydrogen. The surface chemistry of the samples was characterised by infrared spectroscopy, X-ray photoelectron spectroscopy and Boehm titration. The sorption properties of ND were tested fordifferent radionuclides. The sorption capacity of ND was shown to be higher than those of commonly used radionuclide sorbents like activated carbon and compariable to other members of nanocarbon group like graphene oxide and carbon nanotubes. The sorption properties were shown to be influenced by the presence of oxygen-containing groups on the surface of ND. This represents an opportunity to increase the sorption capacity of ND.

  7. Studies on regularities of metal ion sorption from seawater by clinoptilolytes of different origin

    International Nuclear Information System (INIS)

    Khamizov, R.Kh.; Butenko, T.Yu.; Bronov, L.V.; Skovyra, V.V.; Novikova, V.A.; AN SSSR, Vladivostok

    1988-01-01

    The regularities of metal ion sorption from sea water by different clinoptilolyte (CP) samples are studied with the purpose of choosing the most prospective sorbents to extract strontium and rubidium. It is shown that the internal diffusion is the sorption rate determining stage. The dependence of effective coefficients of internal diffusion on the exchange level is determined. The distribution coefficients and those of single metal ion separation are determined, the series of sorption selectivity are determined. All CP studied can be used for initial Rb concentration from sea water, and to extract strontium it is advisable to use zeolites of Dzegvi and Tedzami deposits

  8. Natural minerals and synthetic materials for sorption of radioactive anions

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Mun Ja; Chun, Kwan Sik; Kim, Seung Soo

    1998-07-01

    Technetium-99 and iodine-129 are fission products with long half-lives, and exist as highly soluble anionic species. Studies on natural and synthetic materials sorbing TcO{sub 4} and/or I have been performed by several researchers. The application of these materials as an additive in the high-level waste disposal has been considered. The iron- or sulfide-containing minerals such as metal iron, iron powder, stibnite and pyrrhotite show a high capacity for TcO{sub 4} sorption. And the small amounts of activated carbon are reported to have high distribution coefficients recently. In the iodine sorption studies, sulfide-, copper-, lead- or mercury-containing minerals can be a candidate. Pyrite, chalcopyrite, galena, Cu{sub 2}S and CuS reveal a high capacity for I sorption. The synthetic materials were found to have high sorption capacity and compensate the defects of natural minerals, which contain hydrous oxides such as zirconium oxide, aluminium oxide and mercarbide. The mercarbide has the high distribution coefficients for the sorption of TcO{sub 4} and I. Recently it was proposed that the synthetic clay, hydrotalcite, could be useful for the fixation of anion. However, to determine the applicability of those natural and synthetic materials as an additive to a buffer or backfill material for sorption of TcO{sub 4} and/or I, the sorption behavior of the anions on those materials under the repository conditions should be identified. (author). 32 refs., 21 tabs., 10 figs

  9. Pu sorption to activated conglomerate anaerobic bacteria

    International Nuclear Information System (INIS)

    Sasaki, Takayuki; Kudo, Akira

    2001-01-01

    The sorption of Pu to the anaerobic bacteria activated under specific conditions of temperature, pH and depleted nutrients after long dormant period was investigated. After 4 h at neutral pH, the distribution coefficient (K d ) between bacteria and aqueous phase at 308 and 278 K had around 10 3 to 10 4 . After over 5 days, however, the K d at only 308 K had increased to over 10 5 . Sterilized (dead) and dormant anaerobic bacteria adsorbed Pu to the same extent. (author)

  10. Radionuclides sorption in clay soils

    International Nuclear Information System (INIS)

    Siraky, G.; Lewis, C.; Hamlat, S.; Nollmann, C.E.

    1987-01-01

    The sorption behaviour of clay soils is examined through a parametric study of the distribution coefficient (Kd) for the radionuclides of interest, Cs and Sr. This work is a preliminary stage of the migration studies of these nuclides in a porous medium (ground of Ezeiza, Argentina) and the evaluation of radiologic impact of the removal of low and intermediate activity wastes in shallow trenches. The determination of Kd is performed by a static technique or batch. The phases are separated by centrifugation at 20000 g during 1 hour. The activity of supernatant solution of Cs-137 and Sr-85 is measured in a detecting system of I Na(Tl) well-type. Two types of parameters were changed: a) those related to the determination method: phase separation (centrifugation vs. centrifugation plus filtration); equilibrium period, ratio solid/liquid; b) those related to the geochemical system: pH of contact solution, carrier concentration, competitive ions, ionic strength, desorption. It was observed that the modification of parameters in the Kd-measurement does not change the order of magnitude of results. (Author)

  11. Sorption of cesium in young till soils

    Energy Technology Data Exchange (ETDEWEB)

    Lusa, Merja; Lempinen, Janne; Ahola, Hanna; Soederlund, Mervi; Lehto, Jukka [Helsinki Univ. (Finland). Laboratory of Radiochemistry; Lahdenperae, Anne-Maj [Saanio and Riekkola Oy, Consulting Engineers, Helsinki (Finland); Ikonen, Ari T.K. [Posiva Oy, Eurajoki (Finland)

    2014-10-01

    Soil samples from three forest soil pits were examined down to a depth of approximately three metres using 1 M ammonium acetate extraction and microwave-assisted extraction with concentrated nitric acid (HNO{sub 3}), to study the binding of cesium (Cs) at Olkiluoto Island, southern Finland. Ammonium acetate was used to extract the readily exchangeable Cs fractions roughly representing the Cs fraction in soil which is available for plants. Microwave-assisted HNO{sub 3} extraction dissolves various minerals, e.g. carbonates, most sulphides, arsenides, selenides, phosphates, molybdates, sulphates, iron (Fe) and manganese (Mn) oxides and some silicates (olivine, biotite, zeolite), and reflects the total Cs concentrations. Cs was mostly found in the strongly bound fraction obtained through HNO{sub 3} extraction. The average Cs concentrations found in this fraction were 3.53 ± 0.30 mg/kg (d.w.), 3.06 ± 1.86 mg/kg (d.w.) and 1.83 ± 0.42 mg/kg (d.w.) in the three soil pits, respectively. The average exchangeable Cs found in the ammonium acetate extraction in all three sampling pits was 0.015 ± 0.008 mg/kg (d.w.). In addition, Cs concentrations in the soil solution were determined and in situ distribution coefficients (K{sub d}) for Cs were calculated. Furthermore, the in situ K{sub d} data was compared with the Cs K{sub d} data obtained using the model batch experiments. The in situ K{sub d} values were observed to fairly well follow the trend of batch sorption data with respect to soil depth, but on average the batch distribution coefficients were almost an order of magnitude higher than the in situ K{sub d} data. In situ Cs sorption data could be satisfactory fitted with the Langmuir sorption isotherm, but the Freundlich isotherm failed to fit the data. Finally, distribution coefficients were calculated by an ion exchange approach using soil solution data, the cation exchange capacity (CEC) as well as Cs to sodium (Na) and Cs to potassium (K) ion exchange selectivity

  12. Sorption of 241Am onto montmorillonite, illite and hematite colloids

    International Nuclear Information System (INIS)

    Degueldre, C.; Ulrich, H.J.; Silby, H.

    1994-01-01

    Actinide sorption on colloids may be described as a competition between the formation of complexes in solution and the build up of surface complexes. The role of particle and of carbonate concentrations on the sorption/desorption of 241 Am on montmorillonite, illite and hematite colloids is investigated. Since the partition coefficient (K p ) values are virtually independent of the colloid concentrations, within the range 1 to 300 ppm, no significant aggregation takes place in the sorption/desorption experiment. At pH 8, a slight decrease of K p is observed if the concentration of total carbonate exceeds 10 -2 M. The formation of the carbonato- (and hydroxo-carbonato-) complexes in the solution competes with the formation of surface complexes on the colloids. A relationship between the sorption coefficient and the complexation of 241 Am in the solution has been found. This leads to the conclusion that, besides free americium cation, the hydroxo-, and carbonato- as well as the mixed hydroxo-carbonato-complexes are sorbed. Only when the tricarbonatocomplex [Am(CO 3 ) 3 ] 3- prevails (total carbonate concentration > 10 -2 M), a significant decrease of the distribution coefficient is observed. At pH 10 this decrease disappears because under these conditions the strong hydroxo-complexes dominate. A pragmatic and relatively simple application of surface complexation model describes the observed features. (orig.)

  13. Performance of chromatographic systems to model soil-water sorption.

    Science.gov (United States)

    Hidalgo-Rodríguez, Marta; Fuguet, Elisabet; Ràfols, Clara; Rosés, Martí

    2012-08-24

    A systematic approach for evaluating the goodness of chromatographic systems to model the sorption of neutral organic compounds by soil from water is presented in this work. It is based on the examination of the three sources of error that determine the overall variance obtained when soil-water partition coefficients are correlated against chromatographic retention factors: the variance of the soil-water sorption data, the variance of the chromatographic data, and the variance attributed to the dissimilarity between the two systems. These contributions of variance are easily predicted through the characterization of the systems by the solvation parameter model. According to this method, several chromatographic systems besides the reference octanol-water partition system have been selected to test their performance in the emulation of soil-water sorption. The results from the experimental correlations agree with the predicted variances. The high-performance liquid chromatography system based on an immobilized artificial membrane and the micellar electrokinetic chromatography systems of sodium dodecylsulfate and sodium taurocholate provide the most precise correlation models. They have shown to predict well soil-water sorption coefficients of several tested herbicides. Octanol-water partitions and high-performance liquid chromatography measurements using C18 columns are less suited for the estimation of soil-water partition coefficients. Copyright © 2012 Elsevier B.V. All rights reserved.

  14. Use of thermodynamic sorption models to derive radionuclide Kd values for performance assessment: Selected results and recommendations of the NEA sorption project

    Science.gov (United States)

    Ochs, M.; Davis, J.A.; Olin, M.; Payne, T.E.; Tweed, C.J.; Askarieh, M.M.; Altmann, S.

    2006-01-01

    For the safe final disposal and/or long-term storage of radioactive wastes, deep or near-surface underground repositories are being considered world-wide. A central safety feature is the prevention, or sufficient retardation, of radionuclide (RN) migration to the biosphere. To this end, radionuclide sorption is one of the most important processes. Decreasing the uncertainty in radionuclide sorption may contribute significantly to reducing the overall uncertainty of a performance assessment (PA). For PA, sorption is typically characterised by distribution coefficients (Kd values). The conditional nature of Kd requires different estimates of this parameter for each set of geochemical conditions of potential relevance in a RN's migration pathway. As it is not feasible to measure sorption for every set of conditions, the derivation of Kd for PA must rely on data derived from representative model systems. As a result, uncertainty in Kd is largely caused by the need to derive values for conditions not explicitly addressed in experiments. The recently concluded NEA Sorption Project [1] showed that thermodynamic sorption models (TSMs) are uniquely suited to derive K d as a function of conditions, because they allow a direct coupling of sorption with variable solution chemistry and mineralogy in a thermodynamic framework. The results of the project enable assessment of the suitability of various TSM approaches for PA-relevant applications as well as of the potential and limitations of TSMs to model RN sorption in complex systems. ?? by Oldenbourg Wissenschaftsverlag.

  15. Sorption behavior of thorium onto montmorillonite and illite

    International Nuclear Information System (INIS)

    Iida, Yoshihisa; Barr, Logan; Yamaguchi, Tetsuji; Hemmi, Ko

    2016-01-01

    Thorium (Th)-229 is one of the important radionuclides for the performance assessment calculations for high-level radioactive waste repositories. The sorption behavior of Th onto montmorillonite and illite were investigated by batch sorption experiments. Experiments were carried out under variable pH and carbonate concentrations. The sorbability of montmorillonite was higher than that of illite. Distribution coefficients, K d (m 3 kg -1 ), decreased with increased carbonate concentrations and showed the minimal value at around pH 10. The sorption behaviors of Th were analyzed by the non-electrostatic surface complex model with PHREEQC computer program. The model calculations were able to explain the experimental results reasonably well. The decreases of K d was likely due to the stabilization of aqueous species by hydroxo-carbonate complexations in the solutions. (author) [ja

  16. Investigation of strontium sorption on Kula volcanites treated with HCl

    International Nuclear Information System (INIS)

    Kuetahyali, C.; Cetinkaya, B.; Acar, M. B.; Isik, N. O.; Cireli, I.

    2009-01-01

    In planning the disposal of radioactive waste in a deep geologic repository, consideration must be given to the ways in which radionuclides might leave the repository and migrate through the geosphere. In performance assessment studies the uptake of the radioactive elements by rock formations play an important role in retarding their aqueous phase migration. Sorption studies of radionuclides have been conducted to obtain data on the distribution coefficient (K d ) that is as an input parameter in the performance assessment of the geological disposal of radioactive wastes. In many studies, the sorption experiments employed natural soils and rocks as sorbents. Adsorption experiments were studied in a batch adsorption system using Sr(NO 3 ) 2 (Merck) solution. Strontium sorption on Kula Volcanites treated with HCl was investigated. Central Composite Design Method was used in the experiments. Sr adsorption was studied as a function of pH, contact time, concentration of adsorbate, and temperature.

  17. Sericitization of illite decreases sorption capabilities for cesium

    Science.gov (United States)

    Choung, S.; Hwang, J.; Han, W.; Shin, W.

    2017-12-01

    Release of radioactive cesium (137Cs) to environment occurs through nuclear accidents such as Chernobyl and Fukushima. The concern is that 137Cs has long half-life (t1/2 = 30.2 years) with chemical toxicity and γ-radiation. Sorption techniques are mainly applied to remove 137Cs from aquatic environment. In particular, it has been known well that clay minerals (e.g, illite) are effective and economical sorbents for 137Cs. Illite that was formed by hydrothermal alteration exist with sericite through "sericitization" processes. Although sericite has analogous composition and lattice structure with illite, the sorptive characteristics of illite and sericite for radiocesium could be different. This study evaluated the effects of hydrothermal alteration and weathering process on illite cesium sorption properties. Natural illite samples were collected at Yeongdong area in Korea as the world-largest hydrothermal deposits for illite. The samples were analyzed by XRF, XRD and SEM-EDX to determine mineralogy, chemical compositions and morphological characteristics, and used for batch sorption experiments. The Yeongdong illites predominantly consist of illite, sericite, quartz, and albite. The measured cesium sorption distribution coefficients (Kd,Cs) of reference illite and sericite were approximately 6000 and 400 L kg-1 at low aqueous concentration (Cw 10-7 M), respectively. In contrast, Kd,Cs values for the Yeongdong illite samples ranged from 500 to 4000 L kg-1 at identical concentration. The observed narrow and sharp XRD peak of sericite indicated that the sericite has better crystallinity compared to illite. These experimental results suggested that sericitization processes of illite can decline the sorption capabilities of illite for cesium under various hydrothermal conditions. In particular, weathering experiments raised the cesium sorption to illite, which seems to be related to the increase of preferential sorption sites for cesium through crystallinity destruction

  18. Sorption of thiabendazole in sub-tropical Brazilian soils.

    Science.gov (United States)

    de Oliveira Neto, Odilon França; Arenas, Alejandro Yopasa; Fostier, Anne Hélène

    2017-07-01

    Thiabendazole (TBZ) is an ionizable anthelmintic agent that belongs to the class of benzimidazoles. It is widely used in veterinary medicine and as a fungicide in agriculture. Sorption and desorption are important processes influencing transport, transformation, and bioavailability of xenobiotic compounds in soils; data related to sorption capacity are therefore needed for environmental risk assessments. The aim of this work was to assess the sorption potential of TBZ in four Brazilians soils (sandy, sandy-clay, and clay soils), using batch equilibrium experiments at three pH ranges (2.3-3.0, 3.8-4.2, and 5.5-5.7). The Freundlich sorption coefficient (K F ) ranged from 9.0 to 58 μg 1-1/n  (mL) 1/n  g -1 , with higher values generally observed at the lower pH ranges (2.3-3.0 and 3.8-4.2) and for clay soils. The highest organic carbon-normalized sorption coefficients (K OC ) obtained at pH 3.8-5.7 (around the natural pH range of 4.1-5.0) for both clay soils and sandy-clay soil were 3255 and 2015 mL g -1 , respectively. The highest correlations K F vs SOM (r = 0.70) and K F vs clay content (r = 0.91) were observed at pH 3.8-4.2. Our results suggest that TBZ sorption/desorption is strongly pH dependent and that its mobility could be higher in the studied soils than previously reported in soils from temperate regions.

  19. Sorption-desorption behavior of polybrominated diphenyl ethers in soils

    International Nuclear Information System (INIS)

    Olshansky, Yaniv; Polubesova, Tamara; Vetter, Walter; Chefetz, Benny

    2011-01-01

    Polybrominated diphenyl ethers (PBDEs) are flame retardants that are commonly found in commercial and household products. These compounds are considered persistent organic pollutants. In this study, we used 4,4'-dibromodiphenyl ether (BDE-15) as a model compound to elucidate the sorption and desorption behavior of PBDEs in soils. The organic carbon-normalized sorption coefficient (K OC ) of BDE-15 was more than three times higher for humin than for bulk soils. However, pronounced desorption hysteresis was obtained mainly for bulk soils. For humin, increasing concentration of sorbed BDE-15 resulted in decreased desorption. Our data illustrate that BDE-15 and probably other PBDEs exhibit high sorption affinity to soils. Moreover, sorption is irreversible and thus PBDEs can potentially accumulate in the topsoil layer. We also suggest that although humin is probably a major sorbent for PBDEs in soils, other humic materials are also responsible for their sequestration. - Highlights: → BDE-15 exhibited pronounced desorption hysteresis. → BDE-15 sowed higher sorption affinity to humin as compared to the bulk soils. → Sequestration of PBDEs depends on soil organic matter constitutes other than humin. - Pronounced desorption hysteresis was observed for BDE-15 in natural soils.

  20. Study of sorption processes of strontium on the synthetic hydroxyapatite

    International Nuclear Information System (INIS)

    Rosskopfova, O.; Galambos, M.; Rajec, P.

    2011-01-01

    The sorption of strontium on synthetic hydroxyapatite was investigated using batch method and radiotracer technique. The hydroxyapatite samples were prepared by a wet precipitation process followed by calcination of calcium phosphate that precipitated from aqueous solution. Also, commercial hydroxyapatites were used. The sorption of strontium on hydroxyapatite depended on the method of preparation and it was pH independent ranging from 4 to 9 as a result of buffering properties of hydroxyapatite. The distribution coefficient K d was significantly decreased with increasing concentration of Sr 2+ and Ca 2+ ions in solution with concentration above 1 x 10 -3 mol dm -3 . The percentage strontium sorption for commercial and by wet method prepared hydroxyapatite was in the range of 83-96%, while calcined hydroxyapatite was ranging from 10 to 30%. The experimental data for sorption of strontium have been interpreted in the term of Langmuir isotherm. The sorption of Sr 2+ ions was performed by ion-exchange with Ca 2+ cations on the crystal surface of hydroxyapatite. Although calcined hydroxyapatite is successfully used as biomaterial for hard tissues repair, it is not used for the treatment of liquid wastes. (author)

  1. Sorption of Emerging Organic Wastewater Contaminants to Four Soils

    Directory of Open Access Journals (Sweden)

    Sarah Roberts

    2014-04-01

    Full Text Available Conventional onsite wastewater treatment system design relies on a septic tank and soil treatment unit (STU for treatment of wastewater and integration of the final effluent into the environment. Organic water contaminants (OWCs, chemicals found in pharmaceutical drugs, detergents, surfactants, and other personal care and cleaning products, have been observed in septic tank effluent and the environment. Sorption of OWC mass to soil is a key mechanism in the removal and retardation of many of these chemicals in effluent as it travels through an STU. The primary purpose of this study was to investigate the relationship between the fraction of organic carbon of soil and the equilibrium sorption partitioning coefficient of a selected group of relevant and diverse OWCs. A secondary goal is to evaluate current methods of modeling the sorption of selected OWCs in soil. Five point Freundlich isotherms were constructed from equilibrium sorption batch tests for target OWCs with four different soils. For soils with organic carbon fraction between 0.021 and 0.054, Kd values were calculated between 60 and 185 for 4-nonylphenol, 75 to 260 for triclosan, 115 to 270 for bisphenol-A, 3 to 255 for 17β-estradiol, 40 to 55 for 17α-ethynylestradiol, and 28 to 70 for estrone. An empirically derived, direct relationship between foc and Kd may be a useful approach to estimating sorption for a soil based on organic carbon content.

  2. Sorption behaviour of well-defined oxidation states

    International Nuclear Information System (INIS)

    Allard, B.; Olofsson, U.; Torstenfelt, B.; Kipatsi, H.

    1983-05-01

    The sorption of the actinides Am(III), Th(IV), Np(V), Pa(V), U(VI) and Pu has been studied as a function of pH (2-12) for two nuclide concentrations (10 -7 -10 -9 M) (only one for Pa and U) in the systems Al 2 0 3 - 0.01 M NaCl0 4 and Si0 2 - 0.01 M NaCl0 4 . Distribution coefficients have been determined by a batch technique after various contact times (6h - 6w) at constant temperature (25degreeC) in systems equilibrated with air. The observed sorption behaviour indicates a predominantly physical adsorption mechanism, where pH of the aqueous phase is the principal chemical parameter of influence. The sorption is highly related to the degree of hydrolysis, with a maximum in the pH-region where neutral species dominate and with a reduction of the sorption under conditions when anionic species (hydroxides or carbonates) would exist in solution. This is particularly the case for U(VI) at pH above 7-8 when anionic carbonate complexes would be formed. Plutonium is predominantly tetravalent under the present conditions, as indicated by the sorption behaviour. (authors)

  3. Batch-Versuche zur Bestimmung der Sorption und Reaktionskinetik von fluoreszierenden Tracern

    Science.gov (United States)

    Vaitl, Tobias; Wohnlich, Stefan

    2018-06-01

    For many tracer experiments, prior determination of interaction between solid medium and used tracers is of major interest in order to achieve efficient, economic and successful field experiments. In the present study, three different types of batch experiments were performed with three fluorescent dyes (Na-Fluorescein, Amidorhodamin G and Tinopal CBS-X) and three different rock types (sandstone, claystone and limestone), to determine distribution coefficients and reaction kinetics. All three rock types were analysed for organic carbon content, specific surface area and mineralogical composition to identify the main sorption mechanisms. For all tracers, different sorption properties were found depending on the type of rock. The strongest sorption was observed for Tinopal CBS-X in contact with claystone. Only Na-Fluorescein showed sorption (albeit limited) in contact with the sandstones. The investigated limestones indicated a high sorption for the tracer Tinopal CBS-X. Regarding reaction kinetics, in most cases, thermodynamic equilibrium conditions were reached after two weeks.

  4. Sorption properties of carbon nanostructures

    International Nuclear Information System (INIS)

    Eletskii, Aleksandr V

    2004-01-01

    The current status of research in sorption properties of carbon nanotubes (CNTs) is reviewed. The structural peculiarities of CNTs, determining their sorption characteristics, are considered. The mechanisms of sorption of gaseous and condensed substances by such structures are analyzed. Special attention is paid to the problem of using CNTs for storing hydrogen and other gaseous substances. Methods for filling CNTs with liquid materials, based on capillary phenomena and wetting the graphite surface of the CNT with liquids of various nature, are considered. Properties of 'peapods' formed as a result of filling single-walled CNTs with fullerene molecules are reviewed. Also considered are perspectives on the applied usage of the sorption properties of CNTs in electrochemical and fuel cells, and material storage devices, as well as for producing superminiature metallic conductors. (reviews of topical problems)

  5. Sorption of radionuclides on geologic media - A literature survey. I: Fission Products

    International Nuclear Information System (INIS)

    Andersson, K.; Allard, B.

    1983-01-01

    The fission products investigated were cobalt, nickel, strontium, cesium, technetium and iodine. Parameters of importance to sorption have been identified and a tabulation of distribution coefficients for groundwater conditions (pH 7-9, low to medium ionic strength) is included in the report. For cobalt and nickel the sorption is related to hydrolysis. High sorption is observed at a pH where hydrolysis become important and the sorption is high as long as cationic hydrolysis products are formed. When pH is increased or negatively charged hydrolysis products may be formed and the sorption decreases. For strontium hydrolysis is of no importance at the normal pH of groundwater, but in groundwater above pH 9 carbonate complexation may occur. For most minerals, the sorption is low, ususally with a pronounced pH dependence. Other important parameters are ionic strength and CEC. A nonselective sorption due to electrostatic interactions between negatively charged mineral surfaces and Sr 2+ seems to occur. For cesium no hydrolysis may be expected and pH has less importance than for Sr. For most minerals, however, the sorption of Cs is higher than for Sr. Important parameters are nuclide concentration and ionic strength. A selective for Cs-sorption is found for some minerals, mostly sheet-silicates. For technetium sorption is due to a reduction of TcO 4 - TcO 2 (s) and as anions are poorly sorbed, the sorption is dependent on the redox potential. Iodine is also anionic and poorly sorbed. Minerals containing ions capable of forming iodides with low solubility (Ag, Mg, Pb etc) are, however, sorbing I - . (Author)

  6. SITE-94. Adaptation of mechanistic sorption models for performance assessment calculations

    International Nuclear Information System (INIS)

    Arthur, R.C.

    1996-10-01

    Sorption is considered in most predictive models of radionuclide transport in geologic systems. Most models simulate the effects of sorption in terms of empirical parameters, which however can be criticized because the data are only strictly valid under the experimental conditions at which they were measured. An alternative is to adopt a more mechanistic modeling framework based on recent advances in understanding the electrical properties of oxide mineral-water interfaces. It has recently been proposed that these 'surface-complexation' models may be directly applicable to natural systems. A possible approach for adapting mechanistic sorption models for use in performance assessments, using this 'surface-film' concept, is described in this report. Surface-acidity parameters in the Generalized Two-Layer surface complexation model are combined with surface-complexation constants for Np(V) sorption ob hydrous ferric oxide to derive an analytical model enabling direct calculation of corresponding intrinsic distribution coefficients as a function of pH, and Ca 2+ , Cl - , and HCO 3 - concentrations. The surface film concept is then used to calculate whole-rock distribution coefficients for Np(V) sorption by altered granitic rocks coexisting with a hypothetical, oxidized Aespoe groundwater. The calculated results suggest that the distribution coefficients for Np adsorption on these rocks could range from 10 to 100 ml/g. Independent estimates of K d for Np sorption in similar systems, based on an extensive review of experimental data, are consistent, though slightly conservative, with respect to the calculated values. 31 refs

  7. Detection of tritium sorption on four soil materials

    International Nuclear Information System (INIS)

    Teng Yanguo; Zuo Rui; Wang Jinsheng; Hu Qinhong; Sun Zongjian; Zeng Ni

    2011-01-01

    In order to measure groundwater age and design nuclear waste disposal sites, it is important to understand the sorption behavior of tritium on soils. In this study, batch tests were carried out using four soils from China: silty clays from An County and Jiangyou County in Sichuan Province, both of which could be considered candidate sites for Very Low Level Waste disposal; silty sand from Beijing; and loess from Yuci County in Shanxi Province, a typical Chinese loess region. The experimental results indicated that in these soil media, the distribution coefficient of tritium is slightly influenced by adsorption time, water/solid ratio, initial tritium specific activity, pH, and the content of humic and fulvic acids. The average distribution coefficient from all of these influencing factors was about 0.1-0.2 mL/g for the four types of soil samples. This relatively modest sorption of tritium in soils needs to be considered in fate and transport studies of tritium in the environment. - Research highlights: → In this study, batch sorption tests validate the adsorption of tritium on all of the four tested soil samples collected in China, and the distribution coefficient is found to be non-zero and less than 0.4 mL/g. The experimental results indicated that in these soil media, the distribution coefficient of tritium is slightly influenced by adsorption time, water/solid ratio, initial tritium specific activity, pH, and the content of humic and fulvic acids. This relatively modest sorption of tritium in soils needs to be considered in fate and transport studies of tritium in the environment.

  8. Sorption of cesium on titanium and zirconium phosphates

    International Nuclear Information System (INIS)

    Lebedev, V.N.; Mel'nik, N.A.; Rudenko, A.V.

    2003-01-01

    Titanium and zirconium phosphates were prepared from mineral raw materials of the Kola Peninsula. Their capability to recover cesium cations from the model solutions and liquid radioactive waste (LRW) was studied. Titanium phosphate prepared from solutions formed by titanite breakdown demonstrates greater distribution coefficients of cesium as compared to zirconium phosphate. Titanium phosphate as a cheaper agent featuring greater sorption capacity was recommended for treatment of LRW to remove cesium [ru

  9. Characteristics of and sorption to biochars derived from waste material

    Science.gov (United States)

    Sun, Huichao; Kah, Melanie; Sigmund, Gabriel; Hofmann, Thilo

    2015-04-01

    Biochars can exhibit a high sorption potential towards heavy metals and organic contaminants in various environmental matrices (e.g., water, soil). They have therefore been proposed for environmental remediation purposes to sequester contaminants. To date, most studies have focused on the physicochemical and sorption properties of mineral phases poor biochars, which are typically produced from plant residues. Only little knowledge is available for biochars derived from human and animal waste material, which are typically characterized by high mineral contents (e.g., sewage sludge, manure). Using human and animal waste as source material to produce biochars would support the development of attractive combined strategies for waste management and remediation. The potential impact of mineral phases on the physicochemical and sorption properties of biochars requires further studies so that the potential as sorbent material can be evaluated. With this purpose, different source material biochars were produced at 200°C, 350°C and 500°C, to yield a series of biochars representing a range of mineral content. The derived biochars from wood shavings (sludge (50-70% ash) and pig manure (30-60% ash), as well as a commercial biochar derived from grain husks (40% ash), were extensively characterized (e.g., element composition, surface area, porosity, Fourier transform infrared spectroscopy). The contents of potentially toxic elements (i.e., heavy metals and polycyclic aromatic hydrocarbons) of all materials were within the guidelines values proposed by the International Biochar Initiative, indicating their suitability for environmental application. Single point sorption coefficients for the model sorbate pyrene were measured to investigate the effect of mineral content, feedstock, pyrolysis temperature, particle size fractions and acid demineralization on sorption behavior. Overall, sorption of pyrene was strong for all materials (4 waste material and exhibiting high mineral

  10. Sorption/desorption reversibility of polycyclic aromatic hydrocarbons (PAHs) in soils and carbonaceous materials

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Guohui

    2008-07-01

    the determination of the sorption/desorption enthalpies which gives insight into the sorbent-sorbate interactions. In order to attain sorption/desorption equilibrium, all the samples were pulverized to shorten the laboratory experimental time. The sorbate losses were carefully monitored and considered in the isotherm calculation. Additionally, release of native phenanthrene was also investigated at different temperatures and compared with the freshly spiked samples to investigate the aging effect. The batch results show that for all individual temperature steps sorption and desorption isotherms coincide. Furthermore, the solubility-normalized sorption/desorption isotherms at different temperatures collapse to unique overall isotherms. Leaching of native phenanthrene occurred at much lower concentrations but was well predicted by extrapolation of the spiked equilibrium sorption isotherms. The absolute values of sorption/desorption isosteric heats ({delta}H) determined are in a range of 19 - 35 kJ mol{sup -1}, which is higher than the heat of aqueous solution of subcooled phenanthrene but much less than the heat of condensation of solid phenanthrene from water. No significant difference of the enthalpies between sorption and desorption was observed. Furthermore, the desorption enthalpy of the native phenanthrene was not significantly higher than expected from the sorption experiments with spiked samples. Sorption and desorption kinetics were monitored in on-line column experiments with stepwise increases of temperature. An intraparticle diffusion model was used to simulate the desorption profile in order to get the apparent diffusion coefficients of phenanthrene from the carbonaceous materials. Desorption activation energies were calculated by Arrhenius relationship based on the high-resolution measurement of concentration increases at each temperature step. The activation energies determined range from 58 - 71 kJ mol{sup -1}. No significant trend of increasing

  11. Sorption/desorption reversibility of polycyclic aromatic hydrocarbons (PAHs) in soils and carbonaceous materials

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Guohui

    2008-07-01

    determination of the sorption/desorption enthalpies which gives insight into the sorbent-sorbate interactions. In order to attain sorption/desorption equilibrium, all the samples were pulverized to shorten the laboratory experimental time. The sorbate losses were carefully monitored and considered in the isotherm calculation. Additionally, release of native phenanthrene was also investigated at different temperatures and compared with the freshly spiked samples to investigate the aging effect. The batch results show that for all individual temperature steps sorption and desorption isotherms coincide. Furthermore, the solubility-normalized sorption/desorption isotherms at different temperatures collapse to unique overall isotherms. Leaching of native phenanthrene occurred at much lower concentrations but was well predicted by extrapolation of the spiked equilibrium sorption isotherms. The absolute values of sorption/desorption isosteric heats ({delta}H) determined are in a range of 19 - 35 kJ mol{sup -1}, which is higher than the heat of aqueous solution of subcooled phenanthrene but much less than the heat of condensation of solid phenanthrene from water. No significant difference of the enthalpies between sorption and desorption was observed. Furthermore, the desorption enthalpy of the native phenanthrene was not significantly higher than expected from the sorption experiments with spiked samples. Sorption and desorption kinetics were monitored in on-line column experiments with stepwise increases of temperature. An intraparticle diffusion model was used to simulate the desorption profile in order to get the apparent diffusion coefficients of phenanthrene from the carbonaceous materials. Desorption activation energies were calculated by Arrhenius relationship based on the high-resolution measurement of concentration increases at each temperature step. The activation energies determined range from 58 - 71 kJ mol{sup -1}. No significant trend of increasing desorption activation

  12. Sorption study of U+6 in Brazilian soils

    International Nuclear Information System (INIS)

    Junior, Antonio P.; Wasserman, Maria A.V.; Mantovano, Jose L.; Carvalho, Leonel M.; Perez, Daniel V.

    2015-01-01

    The uranium mining is one of the main activities of the nuclear fuel cycle that can contribute to the increased exposure to radioactive materials and is one of the main routes of contamination of soil by natural radionuclides. This study investigated the sorption of uranium in brazilian soils, through sorption isotherms performed in batch. In this study, two types of soils were selected: Ferralsols Red and Nitosol. The adjustment of the experimental data to the kinetic models were evaluated by two approaches: the traditional, based on the coefficient of determination (R 2 ); and the theoretical and informative, based on Corrected Akaike Information Criteria (AIC C ). The coefficient of determination (R 2 ), revealed that, although empirical, both the kinetic model, Freundlich and Langmuir, describes satisfactorily the experimental data, showing R 2 values higher than 0.9, while the partition constant model was not suitable for describe these sorption data. The AICC model analysis showed that the Langmuir model fit the U sorption curve well for Ferralsols Red, while the Freundlich model fits better to Nitosol. This study has highlighted the role of organic matter on the sorption of uranium in highly weathered soils, rich in oxyhydroxides and low activity clays. The Kd values reported in this study differ from those recommended by the United States Environmental Protection Agency, therefore must be considered as reference values for highly weathered soils, since it refers to Brazilian pedoenvironmental conditions. The low Kd values obtained in this study allowed to evaluate the high vulnerability of highly weathered soils to uranium contamination. (author)

  13. Sorption study of U{sup +6} in Brazilian soils

    Energy Technology Data Exchange (ETDEWEB)

    Junior, Antonio P.; Wasserman, Maria A.V.; Mantovano, Jose L.; Carvalho, Leonel M., E-mail: apjunior@ien.gov.br, E-mail: mwasserman@ien.gov.br, E-mail: mantovan@ien.gov.br, E-mail: leonel@ien.gov.br [Instituto de Engenharia Nuclear (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil); Perez, Daniel V., E-mail: daniel@cnps.embrapa.br [Empresa Brasileira de Pesquisas Agropecuarias (Embrapa Solos-CNPS), Rio de Janeiro, RJ (Brazil)

    2015-07-01

    The uranium mining is one of the main activities of the nuclear fuel cycle that can contribute to the increased exposure to radioactive materials and is one of the main routes of contamination of soil by natural radionuclides. This study investigated the sorption of uranium in brazilian soils, through sorption isotherms performed in batch. In this study, two types of soils were selected: Ferralsols Red and Nitosol. The adjustment of the experimental data to the kinetic models were evaluated by two approaches: the traditional, based on the coefficient of determination (R{sup 2}); and the theoretical and informative, based on Corrected Akaike Information Criteria (AIC{sub C}). The coefficient of determination (R{sup 2}), revealed that, although empirical, both the kinetic model, Freundlich and Langmuir, describes satisfactorily the experimental data, showing R{sup 2} values higher than 0.9, while the partition constant model was not suitable for describe these sorption data. The AICC model analysis showed that the Langmuir model fit the U sorption curve well for Ferralsols Red, while the Freundlich model fits better to Nitosol. This study has highlighted the role of organic matter on the sorption of uranium in highly weathered soils, rich in oxyhydroxides and low activity clays. The Kd values reported in this study differ from those recommended by the United States Environmental Protection Agency, therefore must be considered as reference values for highly weathered soils, since it refers to Brazilian pedoenvironmental conditions. The low Kd values obtained in this study allowed to evaluate the high vulnerability of highly weathered soils to uranium contamination. (author)

  14. Effect of Suez Canal Marine Sediment on Sorption of Cesium

    International Nuclear Information System (INIS)

    Hassan, H.B.

    2016-01-01

    Suez Canal is surrounded by navigation, industrial, agricultural activities and suffers from high rate of population growth that discharging waste into Suez Canal. The Suez Canal coastal waters are influenced by a complex variety of physical, geochemical and biological processes, which influence the behavior, transport and fate of containments released into the marine environment. Sorption of releasing containment such as cesium in Suez Canal water is investigated because of its toxic effect on the marine environment. The object of present study is to determine the effects some of physical and chemical characteristics of collected sediment samples from the three important locations on Suez Canal (Suez Bay, Bitter Lakes and El- Temsah Lake beaches) on sorption behavior of cesium by using batch experiment. Batch experiment was used to study the sorption of the cesium ion. The sorption process is dependent on mineral constituents of Suez Canal sediment and their characteristics. Analytical methods which included particle size and X-ray diffraction (XRD) analyses found that particle size of Suez Canal sediment samples is characterized by sand to fine sand and quartz is the main mineralogical species. Distribution coefficient (K d ) which represent geochemical processes and particle size of these sediment samples effect on the degree of cesium sorption to the sediment. Also (K d ) increase with increase cation exchangeable capacity (CEC). The Suez Canal sediment samples have low (K d ) values which effected by their physical and chemical properties. Sample (2) has highest distribution coefficient (K d ) between measured samples due to containing ratio 30% of fine sand and high ratio of organic matter.

  15. Sorption of polar and nonpolar organic contaminants by oil-contaminated soil.

    Science.gov (United States)

    Chen, Hong; Chen, Shuo; Quan, Xie; Zhao, Huimin; Zhang, Yaobin

    2008-12-01

    Sorption of nonpolar (phenanthrene and butylate) and polar (atrazine and diuron) organic chemicals to oil-contaminated soil was examined to investigate oil effects on sorption of organic chemicals and to derive oil-water distribution coefficients (K(oil)). The resulting oil-contaminated soil-water distribution coefficients (K(d)) for phenanthrene demonstrated sorption-enhancing effects at both lower and higher oil concentrations (C(oil)) but sorption-reducing (competitive) effects at intermediate C(oil) (approximately 1 g kg(-1)). Rationalization of the different dominant effects was attempted in terms of the relative aliphatic carbon content which determines the accessibility of the aromatic cores to phenanthrene. Little or no competitive effect occurred for butylate because its sorption was dominated by partitioning. For atrazine and diuron, the changes in K(d) at C(oil) above approximately 1 g kg(-1) were negligible, indicating that the presently investigated oil has little or no effect on the two tested compounds even though the polarity of the oil is much less than soil organic matter (SOM). Therefore, specific interactions with the active groups (aromatic and polar domains) are dominantly responsible for the sorption of polar sorbates, and thus their sorption is controlled by available sorption sites. This study showed that the oil has the potential to be a dominant sorptive phase for nonpolar pollutants when compared to SOM, but hardly so for polar compounds. The results may aid in a better understanding of the role of the aliphatic and aromatic domains in sorption of nonpolar and polar organic pollutants.

  16. Kinetics and equilibrium modeling of uranium(VI) sorption by bituminous shale from aqueous solution

    International Nuclear Information System (INIS)

    Ortaboy, Sinem; Atun, Gülten

    2014-01-01

    Highlights: • Oil shales are sedimentary rocks containing a polymeric matter in a mineral matrix. • Sorption potential of bituminous shale (BS) for uranium recovery was investigated. • U(VI) sorption increased with decreasing pH and increasing temperature. • Kinetic data were analyzed based on single and two resistance diffusion models. • The results fit well to the McKay equation assuming film and intraparticle diffusion. - Abstract: Sorption of U(VI) onto a bituminous shale (BS) from a nuclear power plant project site in Black Sea region was investigated for potential risk assessment when it releases into the environment with contaminated ground and surface water. The sorption characteristics of the BS for U(VI) recovery were evaluated as a function of contact time, adsorbent dosage, initial concentration, pH and temperature. Kinetic results fit better with pseudo-second-order model rather than pseudo-first-order. The possibility of diffusion process was analyzed based on Weber–Morris intra-particle diffusion model. The McKay equation assuming film- and intraparticle diffusion better predicted the data than the Vermeulen approximation presuming surface diffusion. Equilibrium sorption data were modeled according to the Langmuir, Dubinin–Radushkevich (D–R) and Freundlich isotherm equations. Sorption capacity increased from 0.10 to 0.15 mmol g −1 in 298–318 K temperature range. FT-IR analysis and pH dependent sorption studies conducted in hydroxide and carbonate media revealed that U(VI) species were sorbed in uranyl and its hydroxo forms on the BS. Desorption studies showed that U(VI) leaching with Black Sea water was negligible from the loaded BS. The activation parameters (E a , ΔH ∗ and ΔG ∗ ) estimated from diffusion coefficients indicated the presence of an energy barrier in the sorption system. However, thermodynamic functions derived from sorption equilibrium constants showed that overall sorption process was spontaneous in nature

  17. Sorption, desorption and extraction of uranium from some sands under dynamic conditions

    International Nuclear Information System (INIS)

    Palagyi, S.; Laciok, A.

    2006-01-01

    Sorption, desorption and extraction behavior of uranium in various fluvial sands of domestic origin were investigated in continuous dynamic column experiments. For the sorption of U(VI) an aqueous 10 -4 M UO 2 (NO 3 ) 2 solution was used at a flow rate of about 0.3 cm 3 /min. Desorption was carried out with demineralized water, and the extraction with 10 -2 M Na 2 CO 3 solution following desorption. The retardation coefficients (R) and hydrodynamic dispersion coefficients (D d ), were determined using an ADE equation. From the experimentally determined values of R, bulk density and porosity, the distribution coefficients (K d ) of the UO 2 2+ species have been calculated for the respective processes. The extent of U sorption in sands, as well as the proportion of desorbed and extracted U from these sands, was also calculated. (author)

  18. Predicting soil-water partitioning of polycyclic aromatic hydrocarbons and polychlorinated biphenyls by desorption with methanol-water mixtures at different temperatures.

    Science.gov (United States)

    Krauss, M; Wilcke, W

    2001-06-01

    We evaluated a method to determine organic carbon-normalized soil-water partition coefficients (Koc) of 20 PAHs and 12 PCBs by desorption in the presence of a cosolvent (methanol fractions of 0.1-0.9) and at different temperatures (20-80 degrees C). The Koc values, the deviation factor from ideal sorption alpha, and the desorption enthalpies delta Hdes were estimated by nonlinear regression of log Koc on the methanol fractions and on T. The Koc values of individual compounds varied up to a factor of 100 among the studied 11 urban soils. The calculated alpha and delta Hdes of individual compounds varied considerably among the soils (coefficients of variation 5-20% and 20-30%, respectively), alpha increased with increasing hydrophobicity of the compounds. A sequential extraction with four temperature/methanol fraction combinations followed by a nonlinear regression allowed for the direct determination of the Koc, alpha, and delta Hdes. The use of less temperature/methanol fraction combinations requires a suitable estimation of alpha and delta Hdes, as their choice may change the obtained Koc values by up to a factor of 10. The proposed method is suitable for a routine determination of Koc values of PAHs and PCBs for small soil samples (2-6 g) and low concentrations (down to 0.3 mg kg-1 of sigma 20 PAHs and 1.2 micrograms kg-1 of sigma 12 PCBs).

  19. Sorption equilibrium of mercury onto ground-up tree fern.

    Science.gov (United States)

    Ho, Yuh-Shan; Wang, Chung-Chi

    2008-08-15

    The sorption behavior of mercury at different temperatures onto ground-up tree fern was investigated. The experimental results were fitted to two two-parameter isotherms, the Freundlich and Langmuir isotherms, as well as to two three-parameter isotherms, the Redlich-Peterson and Sips isotherms to obtain the characteristic parameters of each model. A comparison of best-fitting was performed using the coefficient of determination and Chi-square test. Both the Langmuir and Redlich-Peterson isotherms were found to well represent the measured sorption data. According to the evaluation using the Langmuir equation, the saturated monolayer sorption capacity of mercury ions onto ground-up tree fern was 26.5 mg/g at 298 K. It was noted that an increase in temperature resulted in a higher mercury ion loading per unit weight of the tree fern. In addition, various thermodynamic parameters, such as DeltaG degrees, DeltaH degrees, and DeltaS degrees, were calculated and compared with the sorption of mercury by other sorbents.

  20. Sorption equilibrium of mercury onto ground-up tree fern

    Energy Technology Data Exchange (ETDEWEB)

    Ho, Y.-S. [Department of Chemical Engineering, I-Shou University, No. 1, Section 1, Hsueh-Cheng Road, Ta-Hsu Hsiang, Kaohsiung County 840, Taiwan (China)], E-mail: ysho@isu.edu.tw; Wang, C.-C. [Department of Chemical Engineering, I-Shou University, No. 1, Section 1, Hsueh-Cheng Road, Ta-Hsu Hsiang, Kaohsiung County 840, Taiwan (China)

    2008-08-15

    The sorption behavior of mercury at different temperatures onto ground-up tree fern was investigated. The experimental results were fitted to two two-parameter isotherms, the Freundlich and Langmuir isotherms, as well as to two three-parameter isotherms, the Redlich-Peterson and Sips isotherms to obtain the characteristic parameters of each model. A comparison of best-fitting was performed using the coefficient of determination and Chi-square test. Both the Langmuir and Redlich-Peterson isotherms were found to well represent the measured sorption data. According to the evaluation using the Langmuir equation, the saturated monolayer sorption capacity of mercury ions onto ground-up tree fern was 26.5 mg/g at 298 K. It was noted that an increase in temperature resulted in a higher mercury ion loading per unit weight of the tree fern. In addition, various thermodynamic parameters, such as {delta}G{sup o}, {delta}H{sup o}, and {delta}S{sup o}, were calculated and compared with the sorption of mercury by other sorbents.

  1. Sorption equilibrium of mercury onto ground-up tree fern

    International Nuclear Information System (INIS)

    Ho, Y.-S.; Wang, C.-C.

    2008-01-01

    The sorption behavior of mercury at different temperatures onto ground-up tree fern was investigated. The experimental results were fitted to two two-parameter isotherms, the Freundlich and Langmuir isotherms, as well as to two three-parameter isotherms, the Redlich-Peterson and Sips isotherms to obtain the characteristic parameters of each model. A comparison of best-fitting was performed using the coefficient of determination and Chi-square test. Both the Langmuir and Redlich-Peterson isotherms were found to well represent the measured sorption data. According to the evaluation using the Langmuir equation, the saturated monolayer sorption capacity of mercury ions onto ground-up tree fern was 26.5 mg/g at 298 K. It was noted that an increase in temperature resulted in a higher mercury ion loading per unit weight of the tree fern. In addition, various thermodynamic parameters, such as ΔG o , ΔH o , and ΔS o , were calculated and compared with the sorption of mercury by other sorbents

  2. Distribution coefficients of caesium, chlorine, iodine, niobium, selenium and technetium on Olkiluoto soils

    International Nuclear Information System (INIS)

    Soederlund, M.; Lusa, M.; Virtanen, S.; Vaelimaa, I.; Hakanen, M.; Lehto, J.; Lahdenperae, A.-M.

    2014-02-01

    Retention of caesium, chlorine, iodine, niobium, selenium and technetium was investigated on soil samples from Olkiluoto using laboratory batch sorption experiments. Distribution coefficients were measured for both dried and sieved and untreated (wet, not sieved) mineral soil and humus in aerobic and anaerobic conditions. Mineralogical composition of the samples was determined by XRD-analysis. Caesium was sorbed efficiently on mineral soil samples and less efficiently on humus. Sorption decreased with decreasing cation exchange capacity and clay fraction content. The effect of competing cations decreased in the order Cs + >NH 4 + >K + >Ca 2+ >Na + . Chlorine was not retained by mineral soil samples, and the sorption was weak on humus. The sorption of iodine was the strongest on humus and the weakest on the untreated mineral soil samples in the anaerobic conditions. In the mineral soil samples, the sorption decreased with decreasing organic matter content and increasing pH. The retention of niobium on soil samples was the most efficient among the studied elements. The retention was high regardless of the aeration conditions. Sorption on humus was smaller. Selenium was retained efficiently on humus. Sorption on mineral soil samples was stronger in aerobic conditions. Sorption increased with time. Technetium was sorbed well on humus and anaerobic, untreated mineral soil samples. Sorption increased with increasing organic matter content and decreasing redox potential. The results from the sorption experiments are used in the site specific radionuclide migration modelling. (orig.)

  3. Experimental studies of Cs, Sr, Ni, and Eu sorption on Na-illite and the modelling of Cs sorption

    International Nuclear Information System (INIS)

    Poinssot, C.; Baeyens, B.; Bradbury, M.H.

    1999-08-01

    A natural illite (illite du Puy) was purified and converted to the homo-ionic Na-form. The conditioned Na-illite was characterised in terms of its mineralogy, chemical inventory and physico-chemical properties. The structural formula was determined from energy dispersive spectroscopic analyses (SEM/TEM-EDS) and bulk chemistry measurements. A cation exchange capacity of 127 meq kg -1 was determined by the 22 Na isotope dilution method at neutral pH. The Na-CEC was also measured as a function of pH. The stability of Na-illite as a function of pH in the range between 3 and 6 was investigated. At low pH values partial dissolution of the illite occurs releasing the structural elements Al, Si, Mg, and K into solution. The presence of Ca and Sr in solution was interpreted as being due to desorption from cation exchange sites. All of these elements are also present at neutral pH but at considerably lower levels. Such effects cannot be avoided and must be considered in the interpretation of the sorption measurements. The main focus of the experimental work presented here is on the sorption behaviour of Cs, Sr, Ni and Eu on conditioned Na-illite as a function of NaClO 4 background electrolyte concentration (0.1 and 0.01 M), nuclide concentration and pH in the range between 3 and 11. Sorption edge data (R d versus pH) and sorption isotherms (quantity of nuclide sorbed versus equilibrium nuclide concentration) are presented for these four elements. Prior to beginning these experiments, sorption kinetics were measured. The broad based pool of sorption measurements generated from this work will provide the source data sets for subsequent modelling. So far only the Cs sorption measurements have been modelled. A two site cation exchange model was developed to describe the sorption of Cs over the whole range of experimental conditions. The two site types were termed 'frayed edge sites' (FES, high affinity/low capacity) and 'type II sites' (low affinity/high capacity). Selectivity

  4. Behavior of Cs in Grimsel granodiorite. Sorption on main minerals and crushed rock

    Energy Technology Data Exchange (ETDEWEB)

    Muuri, Eveliina; Ikonen, Jussi; Matara-aho, Minja; Voutilainen, Mikko; Siitari-Kauppi, Marja [Helsinki Univ. (Finland). Dept. of Chemistry; Lindberg, Antero [Geological Survey of Finland, Espoo (Finland); Holgersson, Stellan [Chalmers University of Technology, Goeteborg (Sweden). Dept. of Chemical and Biological Engineering, Nuclear Chemistry; Martin, Andrew [Nagra (National Cooperative for the Disposal of Radioactive Waste), Wettingen (Switzerland)

    2016-11-01

    In this study the sorption of cesium was investigated on four different minerals; quartz, plagioclase, potassium feldspar and biotite as well as granodiorite obtained from the Grimsel test site in Switzerland. The experiments were conducted in the presence of the weakly saline Grimsel groundwater simulant by determining the distribution coefficients using batch sorption experiments and PHREEQC-modelling across a large concentration range. In addition, the purity of the minerals was measured by XRD and the specific surface areas by BET method using krypton. The distribution coefficients of cesium were largest on biotite (0.304±0.005 m{sup 3}/kg in 10{sup -8} M). Furthermore, the sorption of cesium on quartz was found to be negligibly small in all investigated concentrations and the sorption of cesium on potassium feldspar and plagioclase showed similar behavior against a concentration isotherm with distribution coefficients of 0.0368±0.0004 m{sup 3}/kg and 0.18±0.04 m{sup 3}/kg in 10{sup -8} M. Finally, cesium sorption behavior on crushed granodiorite followed the trend of one of its most abundant mineral, plagioclase with distribution coefficient values of 0.107±0.003 m{sup 3}/kg in 10{sup -8} M. At low concentrations (<1.0.10{sup -6} M) cesium was sorbed on the frayed edge sites of biotite and once these sites are fully occupied cesium sorbs additionally to the Type II and Planar sites. As a consequence, the sorption of cesium on biotite is decreased at concentrations >1.0.10{sup -6} M. Secondly cesium sorption on potassium feldspar and plagioclase showed similar non-linear behavior with varying concentration. The results were used to assist the interpretation of cesium diffusion process in the 2.5 year in-situ experiment carried out in the underground laboratory at Grimsel test site in Switzerland (2007-2009).

  5. Sorption isotherms, GAB parameters and isosteric heat of sorption

    NARCIS (Netherlands)

    Quirijns, E.J.; Boxtel, van A.J.B.; Loon, van W.K.P.; Straten, van G.

    2005-01-01

    The diffusion-sorption drying model has been developed as a physics-based way to model the decreasing drying rate at low moisture contents. This new model is founded on the existence of different classes of water: free and bound water. The transition between these classes and the corresponding

  6. Sorption behavior of cesium on various soils under different pH levels

    International Nuclear Information System (INIS)

    Giannakopoulou, F.; Haidouti, C.; Chronopoulou, A.; Gasparatos, D.

    2007-01-01

    In the present study we investigated the sorption behavior of Cs in four different soils (sandyloam, loam, clayloam and clay) by using batch experiment. Cs sorption characteristics of the studied soils were examined at 4 mg L -1 Cs concentration, at various pH levels, at room temperature and with 0.01 M CaCl 2 as a background electrolyte. Among different soils the decrease of k d (distribution coefficient) of cesium, at all pH levels, followed the sequence sandyloam > loam > clayloam > clay, indicating that the particle size fractions and especially the clay content plays predominant role on sorption of Cs. The effect of pH on cesium sorption displays a similar pattern for all soils, depending on soil type. At acid pH levels less cesium was sorbed, due to a greater competition with other cations for available sorption sites. The maximum sorption of Cs was observed at pH 8, where the negative charge density on the surface of the absorbents was the highest. For all soils was observed significantly lower Cs sorption at pH 10

  7. Nitrate sorption on activated carbon modified with CaCl2: Equilibrium, isotherms and kinetics

    Directory of Open Access Journals (Sweden)

    Zanella Odivan

    2015-01-01

    Full Text Available In this study, nitrate (NO3- removal from aqueous solutions was investigated using granular activated carbon (GAC modified with CaCl2. Batch sorption studies were performed as a function of sorbent dose, initial nitrate concentration and pH. Sorption was maximized between pH 3 and 9. Studies on the effect of pH showed that the ion exchange mechanism might be involved in the sorption process. The percentage of nitrate removed increased with increasing sorbent concentration, and the ideal sorbent dose was found to be 20 g•L-1. Four isotherm models-Langmuir, Freundlich, Redlich-Peterson and Sips-were used to fit the experimental data. The Redlich-Peterson isotherm model explained the sorption process well and showed the best coefficient of determination (0.9979 and Chi-square test statistic (0.0079. Using the Sips isotherm model, the sorption capacity (qe was found to be 1.93 mg nitrate per g of sorbent. Kinetic experiments indicated that sorption was a fast process, reaching equilibrium within 120 min. The nitrate sorption kinetic data were successfully fitted to a pseudo-second-order kinetic model. The overall results demonstrated potential applications of modified GAC for nitrate removal from aqueous solutions.

  8. Impact of bleaching agents on water sorption and solubility of resin luting cements.

    Science.gov (United States)

    Torabi Ardakani, Mahshid; Atashkar, Berivan; Bagheri, Rafat; Burrow, Michael F

    2017-08-01

    The aim of the present study was to evaluate the effect of distilled water and home and office bleaching agents on the sorption and solubility of resin luting cements. A total of 18 disc-shaped specimens were prepared from each of four resin cements: G-CEM LinkAce, Panavia F, Rely X Unicem, and seT. Specimens were cured according to the manufacturers' instructions and randomly divided into three groups of six, where they were treated with either an office or home bleaching agent or immersed in distilled water (control). Water sorption and solubility were measured by weighing the specimens before and after immersion and desiccation. Data were analyzed using Pearson correlation coefficient, two-way analysis of variance (ANOVA) and Tukey's test. There was a significant, positive correlation between sorption and solubility. Two-way anova showed significant differences among all resin cements tested for either sorption or solubility. Water sorption and solubility of all cements were affected significantly by office bleaching, and even more by home bleaching agents. Sorption and solubility behavior of the studied cements were highly correlated and significantly affected by applying either office or home bleaching agents; seT showed the highest sorption and solubility, whereas Rely X Unicem revealed the lowest. © 2016 John Wiley & Sons Australia, Ltd.

  9. Determination of Chlorinated Solvent Sorption by Porous Material-Application to Trichloroethene Vapor on Cement Mortar.

    Science.gov (United States)

    Musielak, Marion; Brusseau, Mark L; Marcoux, Manuel; Morrison, Candice; Quintard, Michel

    2014-08-01

    Experiments have been performed to investigate the sorption of trichloroethene (TCE) vapor by concrete material or, more specifically, the cement mortar component. Gas-flow experiments were conducted using columns packed with small pieces of cement mortar obtained from the grinding of typical concrete material. Transport and retardation of TCE at high vapor concentrations (500 mg L -1 ) was compared to that of a non-reactive gas tracer (Sulfur Hexafluoride, SF6). The results show a large magnitude of retardation (retardation factor = 23) and sorption (sorption coefficient = 10.6 cm 3 g -1 ) for TCE, compared to negligible sorption for SF6. This magnitude of sorption obtained with pollutant vapor is much bigger than the one obtained for aqueous-flow experiments conducted for water-saturated systems. The considerable sorption exhibited for TCE under vapor-flow conditions is attributed to some combination of accumulation at the air-water interface and vapor-phase adsorption, both of which are anticipated to be significant for this system given the large surface area associated with the cement mortar. Transport of both SF6 and TCE was simulated successfully with a two-region physical non-equilibrium model, consistent with the dual-medium structure of the crushed cement mortar. This work emphasizes the importance of taking into account sorption phenomena when modeling transport of volatile organic compounds through concrete material, especially in regard to assessing vapor intrusion.

  10. Sorption and desorption of glyphosate in Mollisols and Ultisols soils of Argentina.

    Science.gov (United States)

    Gómez Ortiz, Ana Maria; Okada, Elena; Bedmar, Francisco; Costa, José Luis

    2017-10-01

    In Argentina, glyphosate use has increased exponentially in recent years as a result of the widespread adoption of no-till management combined with genetically modified glyphosate-resistant crops. This massive use of glyphosate has created concern about its potential environmental impact. Sorption-desorption of glyphosate was studied in 3 Argentinean soils with contrasting characteristics. Glyphosate sorption isotherms were modeled using the Freundlich equation to estimate the sorption coefficient (K f ). Glyphosate sorption was high, and the K f varied from 115.6 to 1612 mg 1-1/n L 1/n /kg. Cerro Azul soil had the highest glyphosate sorption capacity as a result of a combination of factors such as higher clay content, cation exchange capacity, total iron, and aluminum oxides, and lower available phosphorus and pH. Desorption isotherms were also modeled using the Freundlich equation. In general, desorption was very low (glyphosate strongly sorbs to the soils and that it is almost an irreversible process. Anguil soil had a significantly higher desorption coefficient (K fd ) than the other soils, associated with its lower clay content and higher pH and phosphorus. Glyphosate high sorption and low desorption to the studied soils may prevent groundwater contamination. However, it may also affect its bioavailability, increasing its persistence and favoring its accumulation in the environment. The results of the present study contribute to the knowledge and characterization of glyphosate retention in different soils. Environ Toxicol Chem 2017;36:2587-2592. © 2017 SETAC. © 2017 SETAC.

  11. Investigations of the sorption of pertechnetate on salts of molybdophosphoric acid

    International Nuclear Information System (INIS)

    Suess, M.; Pfrepper, G.

    1983-01-01

    Studies were made to investigate the sorption of pertechnetate on neutral and acid salts of molybdophosphoric acid from nitric acid and in the presence of electrolytes and non-electrolytes. Particular, distribution coefficients from 10 to 100 were found. The sorption of pertechnetate can be increased by the addition of K + , NH 4 + , Rb + and Cs + salts, by the addition of non-electrolytes the distribution coefficients decrease. A saturation capacity of about 0.19 mmol Tc/g ammonium phosphomolybdate was determined from the adsorption isotherms. The formation of alkali metal pertechnetate associates in the sorbent phase can be supposed. (author)

  12. Effect of the cationic composition of sorption solution on the quantification of sorption-desorption parameters of heavy metals in soils

    International Nuclear Information System (INIS)

    Sastre, J.; Rauret, G.; Vidal, M.

    2006-01-01

    We obtained the sorption isotherms of Cd, Cu, Pb and Zn in clay, clay saline and organic soils. The distribution coefficients (K d ) were determined in 0.02 eq l -1 CaCl 2 and in a solution that simulated the soil solution cationic composition. The K d values greatly varied with the composition of the sorption solution and the initial metal concentration. The sorption experiments were complemented with the quantification of the extractable metal, to estimate the reversibility of metal sorption. The extraction yields depended on the metal-soil combination, and the initial metal concentration, showing no correlation with previous K d values. The effect of the solution composition in mobility predictions was estimated through a Retention Factor, defined as the ratio of the K d versus the extraction yield. Results showed that risk was over- or underestimated using the CaCl 2 medium in soils with a markedly different soil solution composition. - Sorption solution composition modifies metal sorption-desorption pattern in soils

  13. Sorption/desorption of Cs on clay and soil fractions from various regions of Turkey

    International Nuclear Information System (INIS)

    Erten, H.N.

    1988-01-01

    The sorption/desorption behaviour of Cs ion in the concentration region of 10 -8 to 10 -4 meqml -1 have been studied using clay and soil fractions from various regions of Turkey. The sorption curves for all the material studied show similar behaviour indicating at least two different sorption processes. One with high and the other with low distribution coefficients. The results of desorption studies indicate that Cs cation is to a large extent attached to the solid material in a reversible manner. The adsorption isotherms were found to be nonlinear in all cases. The increase of R D values with decreasing particle size in most cases, suggests that sorption and/or exchange is primarily a surface phenomenon in the clay and soil fractions studied. 14 figs.; 4 tabs

  14. Iodine sorption of bentonite - radiometric and polarographic study

    International Nuclear Information System (INIS)

    Konirova, R.; Vinsova, H.; Koudelkova, M.; Ernestova, M.; Jedinakova-Krizova, V.

    2003-01-01

    The experiments focused on kinetics of iodine retardation on bentonite, influence of aqueous phase pH, buffering properties of bentonite, etc. were carried out by batch method. Distribution coefficient KD was the criterion applied for evaluation of iodine interaction with solid phase. High sorption potential of bentonite to cationic forms of various radionuclides, resulting from relatively high cation exchange capacity, is generally known. On the other hand the inorganic anions are not adsorbed strongly to mineral surface of clays thus uptake of iodine (occurring mainly at iodide (I - ) or iodate (IO 3 - ) form under oxoic conditions) is limited. The distribution coefficients of iodine anions' sorption on bentonite R reach order of magnitude 10 -1 mL/g. In order to increase the sorption capacity of the solid phase, several additives were added to bentonite. Most of them didn't provide satisfactory results except of the addition of activated carbon, which has high surface area. Electromigration and polarographic methods were used for investigation of the redox state of iodine in aqueous phase and determination of KD values as well. Acquired results were compared with data obtained by radiometric measurements. (authors)

  15. Sorption on inactive repository components

    International Nuclear Information System (INIS)

    Gardiner, M.P.; Smith, A.J.; Williams, S.J.

    1990-11-01

    The near-field of an intermediate level/low level radioactive waste repository will contain significant quantities of iron and steel, Magnox and Zircaloy. Their corrosion products may possess significant sorption capacity for radioelements. The sorption of americium and plutonium onto magnesium hydroxide, zirconium hydroxide, colloidal magnetite and colloidal haematite has been studied under conditions typical of the porewater of a cementitious near-field. R D values ≥ 10 5 m g -1 were measured for both actinides on the oxides and hydroxides. These values are at least as great as those measured on crushed 3:1 Blast Furnace Slag/Ordinary Portland cement. Competitive sorption experiments have shown that sorption onto the corrosion products does not take place in preference to that on the cement or the converse. Magnetite and haematite colloids are positively charged in cement-equilibrated water whilst zirconium hydroxide is negatively charged. Crushed cement was found to be positively charged. Simple experiments show that only a small proportion of haematite colloids is potentially mobile through a column of crushed cement. (author)

  16. Sorption on inactive repository components

    International Nuclear Information System (INIS)

    Gardiner, M.P.; Smith, A.J.; Williams, S.J.

    1990-07-01

    The near-field of an intermediate level/low level radioactive waste repository will contain significant quantities of iron and steel, Magnox and Zircaloy. Their corrosion products may possess significant sorption capacity for radioelements. The sorption of americium and plutonium onto magnesium hydroxide, zirconium hydroxide, colloidal magnetite and colloidal haematite has been studied under conditions typical of the porewater of a cementitious near-field. R D values ≥ 10 5 ml g -1 were measured for both actinides on the oxides and hydroxides. These values are at least as great at those measured on crushed 3:1 Blast Furnace Slag/Ordinary Portland Cement. Competitive sorption experiments have shown that sorption onto the corrosion products does not take place in preference to that on the cement or the converse. Magnetite and haematite colloids are positively charged in cement-equilibrated water whilst zirconium hydroxide is negatively charged. Crushed cement was found to be positively charged. Simple experiments show that only a small proportion of haematite colloids is potentially mobile through a column of crushed cement. (author)

  17. Sorption of radioiodide in an acidic, nutrient-poor boreal bog: insights into the microbial impact

    International Nuclear Information System (INIS)

    Lusa, M.; Bomberg, M.; Aromaa, H.; Knuutinen, J.; Lehto, J.

    2015-01-01

    Batch sorption experiments were conducted to evaluate the sorption behaviour of iodide and the microbial impact on iodide sorption in the surface moss, subsurface peat, gyttja, and clay layers of a nutrient-poor boreal bog. The batch distribution coefficient (K d ) values of iodide decreased as a function of sampling depth. The highest K d values, 4800 L/Kg dry weight (DW) (geometric mean), were observed in the fresh surface moss and the lowest in the bottom clay (geometric mean 90 mL/g DW). In the surface moss, peat and gyttja layers, which have a high organic matter content (on average 97%), maximum sorption was observed at a pH between ∼4 and 5 and in the clay layer at pH 2. The K d values were significantly lower in sterilized samples, being 20-fold lower than the values found for the unsterilized samples. In addition, the recolonization of sterilized samples with a microbial population from the fresh samples restored the sorption capacity of surface moss, peat and gyttja samples, indicating that the decrease in the sorption was due to the destruction of microbes and supporting the hypothesis that microbes are necessary for the incorporation of iodide into the organic matter. Anoxic conditions reduced the sorption of iodide in fresh, untreated samples, similarly to the effect of sterilization, which supports the hypothesis that iodide is oxidized into I 2 /HIO before incorporation into the organic matter. Furthermore, the K d values positively correlated with peroxidase activity in surface moss, subsurface peat and gyttja layers at +20 °C, and with the bacterial cell counts obtained from plate count agar at +4 °C. Our results demonstrate the importance of viable microbes for the sorption of iodide in the bog environment, having a high organic matter content and a low pH. - Highlights: • Sorption of iodide is highest on the surface Sphagnum layer of the bog. • Sterilization of peat decreases the sorption of iodide. • Anoxic conditions decrease

  18. General review of solar-powered closed sorption refrigeration systems

    International Nuclear Information System (INIS)

    Sarbu, Ioan; Sebarchievici, Calin

    2015-01-01

    Highlights: • Provide review of development in solar sorption refrigeration technologies. • Theoretical basis and applications of absorption and adsorption cycles are discussed. • Thermodynamic properties of most common working pairs have been reviewed. • Development of hybrid or thermal energy storage adsorption systems was explored. • A comparison between solar-powered absorption and adsorption systems was performed. - Abstract: The negative environmental impacts of burning fossil fuels have forced the energy research community seriously to consider renewable sources, such as naturally available solar energy. Thermally powered refrigeration technologies are classified into two categories: thermo-mechanical technology and sorption technology (open systems or closed systems). This paper provides a detailed review of the solar closed sorption (absorption and adsorption) refrigeration systems, which utilise working pairs (fluids). After an introduction of the basic principles of these systems, the history of development and recent advances in solar sorption refrigeration technologies are reported. The adsorption cooling typically has a lower heat source temperature requirement than the absorption cooling. Based on the coefficient of performance (COP), the absorption systems are preferred over the adsorption systems, and the higher temperature issues can be easily handled with solar adsorption systems. The thermodynamic properties of most common working fluids, as well as the use of ternary mixtures in solar-powered absorption systems, have been reviewed in this study. The paper also refers to new approaches to increase the efficiency and sustainability of the basic adsorption cycles, such as the development of hybrid or thermal energy storage adsorption systems. This research shows that solar-powered closed sorption refrigeration technologies can be attractive alternatives not only to serve the needs for air-conditioning, refrigeration, ice making, thermal

  19. Sorption and Migration Mechanisms of 237 Np through Sandy Soil

    International Nuclear Information System (INIS)

    Chantaraprachoom, Nanthavan; Tanaka, Tadao

    2003-06-01

    In order to evaluate migration behavior of radioactive nuclides in the disposal of low-level radioactive waste into a shallow land burial, the sorption characteristic and migration behavior of 237 Np through sandy soil was studied. Two experimental methods were performed by using batch and column systems. The distribution coefficients (K d ) obtained from the adsorption and desorption process are rather small about 16 and 21 cm 3 /g respectively. Size distribution of 237 Np species in the influent solution was measured by ultra-filtration technique. Migration mechanism of 237 Np was studied by column experiments. The experimental condition was the influence of volume of eluting solution; 100, 300, 500, 1000 and 2000 ml respectively. The result from five column experiments confirm that the sorption characteristics of 237 Np are mainly controlled by a reversible ion-exchange reaction and the migration of 237 Np in the sandy soil can be estimated by using the K d concept

  20. Sorption data base for performance assessment of radwaste repository

    International Nuclear Information System (INIS)

    Cho, Y.H.; Jung, J.; Lee, J.K.; Hahn, P.S.

    2001-01-01

    Sorption data base (SDB) provides readily available data for the performance assessment of radwaste repository when site-specific data are not available and/or more reference data are needed. The software developed in the Korea Atomic Energy Research Institute (KAERI), SDB-21C, is a graphic user interface (GUI) program that provides efficient and user friendly tools for evaluating the large amount of sorption data. The data base of distribution coefficients compiled in the program contains about 11,000 Nuclear Energy Agency (NEA) data and 2,000 KAERI data up to now while the addition of new data is under progress. Furthermore, the parametric model and its compiled data sets are also included in SDB-21C. (author)

  1. Radionuclide sorption on low-exchange capacity Hanford site soils

    International Nuclear Information System (INIS)

    Routson, R.C.; Barney, G.S.; Smith, R.M.

    1984-01-01

    Trace Distribution Coefficients (Kd values) for 134 Cs, 85 Sr, and 60 Co sorption were found to be a function of sediment type (soil type) and of the solution concentration of macroions including NA + , K + , and Ca +2 over wide macroion concentration ranges. These Kd value functions are required as input sorption parameters to a mass transport model. Four methods were evaluated for measuring the Kd value macroion functional relationships for each sediment type. Precision, bias, and cost effectiveness were compared for choosing a preferred method. The prefered method, an empirical-statistical method (Box-Behnken method), was found to be as precise and unbiased as the other methods and the most cost effective. 12 references, 7 figures, 10 tables

  2. Surface complexation modeling of zinc sorption onto ferrihydrite.

    Science.gov (United States)

    Dyer, James A; Trivedi, Paras; Scrivner, Noel C; Sparks, Donald L

    2004-02-01

    A previous study involving lead(II) [Pb(II)] sorption onto ferrihydrite over a wide range of conditions highlighted the advantages of combining molecular- and macroscopic-scale investigations with surface complexation modeling to predict Pb(II) speciation and partitioning in aqueous systems. In this work, an extensive collection of new macroscopic and spectroscopic data was used to assess the ability of the modified triple-layer model (TLM) to predict single-solute zinc(II) [Zn(II)] sorption onto 2-line ferrihydrite in NaNO(3) solutions as a function of pH, ionic strength, and concentration. Regression of constant-pH isotherm data, together with potentiometric titration and pH edge data, was a much more rigorous test of the modified TLM than fitting pH edge data alone. When coupled with valuable input from spectroscopic analyses, good fits of the isotherm data were obtained with a one-species, one-Zn-sorption-site model using the bidentate-mononuclear surface complex, (triple bond FeO)(2)Zn; however, surprisingly, both the density of Zn(II) sorption sites and the value of the best-fit equilibrium "constant" for the bidentate-mononuclear complex had to be adjusted with pH to adequately fit the isotherm data. Although spectroscopy provided some evidence for multinuclear surface complex formation at surface loadings approaching site saturation at pH >/=6.5, the assumption of a bidentate-mononuclear surface complex provided acceptable fits of the sorption data over the entire range of conditions studied. Regressing edge data in the absence of isotherm and spectroscopic data resulted in a fair number of surface-species/site-type combinations that provided acceptable fits of the edge data, but unacceptable fits of the isotherm data. A linear relationship between logK((triple bond FeO)2Zn) and pH was found, given by logK((triple bond FeO)2Znat1g/l)=2.058 (pH)-6.131. In addition, a surface activity coefficient term was introduced to the model to reduce the ionic strength

  3. Effect of biosurfactant[0] on the sorption of phenanthrene onto original and H2O2-treated soils

    Institute of Scientific and Technical Information of China (English)

    PEI Xiaohong; ZHAN Xinhua; ZHOU Lixiang

    2009-01-01

    The objective of this study was to examine the effect of biosurfactant on sorption of phenanthrene (PHE) onto the original or H2O2-treated black loamy soil (typic isohumisols) and red sandy soil (typic ferralisols). The sorption isotherms were performed with the original and "soft" carbon-removed soils in the presence and absence of biosurfactant (200 mg/L). The sorption and degradation of biosurfactant were investigated. The result showed that organic matter played an important role in PHE sorption onto the black loamy and red sandy soils, and the PHE sorption isotherms on the "soft" carbon-removed soils exhibited more nonlinearity than those on the original soils. The values of partition coefficient (Kd) on the original black loamy soil with or without 200 mg/L biosurfactant were 181.6 and 494.5 mL/g, respectively. Correspondingly, in the red sandy soil, Kd was 246.4 and 212.8 mL/g in the presence or absence of biosurfactant, respectively. The changes of Kd suggested that biosurfactant inhibited PHE sorption onto the black loamy soil, but facilitated PHE sorption onto the red sandy soil. The nonlinearity of PHE sorption isotherm was decreased in the presence of biosurfactant. Site specific sorption might occur during PHE sorption onto both the original and the "soft" carbon-removed soils in the presence of biosurfactant. It was noted that biosurfactant could also be sorbed onto soils. The maximal sorption capacity of the red sandy soil for biosurfactant was (76.9 ± 0.007) μg/g, which was 1.31 times that of black loamy soil. Biosurfactant was degraded quickly in the two selected soils, and 92% of biosurfactant were mineralized throughout the incubation experiment for 7 d. It implied that biosurfactant should be added frequently when the remediation of polycyclic aromatic hydrocarbon (PAH)-contaminated soils was conducted through PAH desorption approach facilitated by biosurfactant.

  4. Influence of organic matter type and medium composition on the sorption affinity of C12-benzalkonium cation

    International Nuclear Information System (INIS)

    Chen, Yi; Hermens, Joop L.M.; Droge, Steven T.J.

    2013-01-01

    We used the 7-μm polyacrylate ion-exchange SPME fibers to investigate C12-benzalkonium sorption to 10 mg/L natural organic matter at concentrations well below the cation-exchange capacity. C12-BAC sorption at constant medium conditions differed within 0.4 log units for two humic acids (Aldrich, Leonardite) and peat (Sphagnum, Pahokee), with similar nonlinear sorption isotherms (K F ∼ 0.8). Sorption to the SPME fibers and Aldrich humic acid (AHA) was reduced at both low pH and high electrolyte concentration, and reduced more strongly by Ca 2+ compared with Na + at similar concentrations. Sorption isotherms for AHA (5–50–500 mM Na + , pH 6) was modeled successfully by the NICA-Donnan approach, resulting in an intrinsic sorption coefficient of 5.35 (C aq = 1 nM). The NICA-Donnan model further explained the stronger specific binding of Ca 2+ compared to Na + by differences in Boltzmann factors. This study provides relevant information to interpret bioavailability of quaternary ammonium compounds, and possibly for other organic cations. -- Highlights: •The ion-exchange SPME was used to investigate C12-benzalkonium sorption behavior. •Sorption to different organic matter differed within 0.4 log units (5 mM Ca 2+ , pH6). •Sorption to AHA was reduced at both low pH and high electrolyte concentration. •The NICA-Donnan approach lead to an intrinsic log D OC,IE of 5.35 (C aq = 1 nM). •The Boltzmann factors in NICA-Donnan model explained the specific binding of Ca 2+ . -- C12-BAC sorption to the four organic matter samples were investigated by the ion-exchange SPME and the NICA-Donnan model explained the different sorption affinities caused by Na + and Ca 2+

  5. Clinoptilolite and palygorskite as sorbents of neutral emerging organic contaminants in treated wastewater: Sorption-desorption studies.

    Science.gov (United States)

    Leal, María; Martínez-Hernández, Virtudes; Meffe, Raffaella; Lillo, Javier; de Bustamante, Irene

    2017-05-01

    Water reuse for aquifer recharge could be an important route for the introduction of emerging organic contaminants (EOCs) into the environment. The installation of a Horizontal Permeable Reactive Barrier (H-PRB) could constitute a tertiary treatment process to remove EOCs from treated domestic wastewater prior to recharge activities. The sorption-desorption behaviour of six neutral EOCs present in treated domestic wastewater (acetaminophen, caffeine, carbamazepine, cotinine, 4-acetamidoantipyrine (4-AAA) and 4-formylaminoantipyrine (4-FAA)) has been evaluated. Clinoptilolite and palygorskite have been studied as sorbents to be installed in the H-PRB. Batch tests were carried out using an EOC initial concentration ranging from 5 to 100 μg L -1 . Apart from acetaminophen and caffeine, both materials showed a limited sorption capacity of neutral EOCs (K d  = 0.63-5.42 L kg -1 ). In general, the experimental results show that EOCs exhibit a higher sorption affinity for clinoptilolite than for palygorskite. With the exception of carbamazepine, the sorption of the compounds occurs mainly by interactions with mineral surfaces as indicated by the comparison of the partition coefficients into organic matter and into mineral surfaces. According to the molecular geometry of the compounds and the sorption sequences observed, it appears that the dimensions of the organic molecules play a key role in the sorption process. All the studied EOCs exhibit irreversible sorption and sorption-desorption hysteresis. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Performance of LiCl Impregnated Mesoporous Material Coating over Corrugated Heat Exchangers in a Solid Sorption Chiller

    Directory of Open Access Journals (Sweden)

    Hongzhi Liu

    2018-06-01

    Full Text Available The composite material made by impregnating 40 wt. % lithium chloride (LiCl into the mesopores of a kind of natural porous rock (Wakkanai Siliceous Shale: WSS micropowders (short for “WSS + 40 wt. % LiCl” had been developed previously, and can be regenerated below 100 °C with a cooling coefficient of performance (COP of approximately 0.3 when adopted as a sorbent in a sorption cooler. In this study, experiments have been carried out on an intermittent solid sorption chiller with the WSS + 40 wt. % LiCl coating over two aluminum corrugated heat exchangers. Based on the experimental condition (regeneration temperature of 80 °C, condensation temperature of 30 °C in the desorption process; sorption temperature of 30 °C and evaporation temperature of 12 °C in the sorption process, the water sorption amount changes from 20 wt. % to 70 wt. % in one sorption cooling cycle. Moreover, a specific cooling power (SCP of 86 W/kg, a volumetric specific cooling power (VSCP of 42 W/dm3, and a specific sorption power of 170 W/kg can be achieved with a total sorption and desorption time of 20 min. The obtained cooling COP is approximately 0.16.

  7. Selection of sorption material for tests of pesticide permeation through protective clothing fabrics.

    Science.gov (United States)

    Krzemińska, Sylwia; Nazimek, Teresa

    2004-01-01

    The paper presents the results of studies on selecting a solid sorption material for absorbing liquid crop protection agents which permeate samples of protective clothing fabrics. The sorption materials were investigated and selected with an assumption that they should have a high recovery coefficient for biologically active substances, used as active ingredients in crop protection agents, at a presumed, acceptably high level. The selected substances were determined with a gas chromatograph equipped with an electron capture detector (dichlorvos, cypermethrin and 2,4-D) and a nitrogen-phosphorus detector (carbofuran). The tests demonstrated that polypropylene melt-blown type unwoven cloth had high recovery coefficients for all 4 active ingredients proposed for the study. The highest recovery coefficient, -.97, was obtained for carbofuran. The recovery coefficients obtained for the 3 remaining substances were lower: .89 for cypermethrin and 2,4-D, and .84 for dichlorvos.

  8. Removal of cobalt and strontium from groundwater by sorption onto fishbone

    International Nuclear Information System (INIS)

    Younjin Park; Won Sik Shin; Sang-June Choi

    2013-01-01

    Fishbone as a main backfill material of permeable reactive barrier to remediate groundwater contaminated with Co and Sr was investigated through single- and bi-solute competitive sorptions. The single-solute sorption data were fitted by Freundlich, Langmuir and Dubinin-Radushkevich models. The coefficients of determination (R 2 > 0.91) indicated that all models fitted well. Maximum sorption capacities (q mL ) of Co and Sr predicted by the Langmuir model were 0.55 mmol/g and 0.50 mmol/g, respectively. The bi-solute competitive sorption of the metals was analyzed by the Langmuir, competitive Langmuir, Sheindorf-Rebhun-Sheintuch (SRS) and P-factor models. The sorbed amount of one solute in bi-solute system decreased due to competition with the other solute. Langmuir model parameters for single- (q mL and b L ) and bi-solute (q mL * and b L * ) competitive sorptions were compared to analyze the effect of competition between the metals. The competitive Langmuir, SRS and P-factor models predicted the bi-solute competitive sorption data well (R 2 > 0.93). (author)

  9. Sorption and biodegradation characteristics of the selected pharmaceuticals and personal care products onto tropical soil.

    Science.gov (United States)

    Foolad, Mahsa; Hu, Jiangyong; Tran, Ngoc Han; Ong, Say Leong

    2016-01-01

    In the present study, the sorption and biodegradation characteristics of five pharmaceutical and personal care products (PPCPs), including acetaminophen (ACT), carbamazepine (CBZ), crotamiton (CTMT), diethyltoluamide (DEET) and salicylic acid (SA), were studied in laboratory-batch experiments. Sorption kinetics experimental data showed that sorption systems under this study were more appropriately described by the pseudo second-order kinetics with a correlation coefficient (R2)>0.98. Sorption equilibrium data of almost all target compounds onto soil could be better described by the Freundlich sorption isotherm model. The adsorption results showed higher soil affinity for SA, following by ACT. Results also indicated a slight effect of pH on PPCP adsorption with lower pH causing lower adsorption of compounds onto the soil except for SA at pH 12. Moreover, adsorption of PPCPs onto the soil was influenced by natural organic matter (NOM) since the higher amount of NOM caused lower adsorption to the soil. Biodegradation studies of selected PPCPs by indigenous microbial community present in soil appeared that the removal rates of ACT, SA and DEET increased with time while no effect had been observed for the rest. This study suggests that the CBZ and CTMT can be considered as suitable chemical sewage indicators based on their low sorption affinity and high resistance to biodegradation.

  10. Sorption Energy Maps of Clay Mineral Surfaces

    International Nuclear Information System (INIS)

    Cygan, Randall T.; Kirkpatrick, R. James

    1999-01-01

    A molecular-level understanding of mineral-water interactions is critical for the evaluation and prediction of the sorption properties of clay minerals that may be used in various chemical and radioactive waste disposal methods. Molecular models of metal sorption incorporate empirical energy force fields, based on molecular orbital calculations and spectroscopic data, that account for Coulombic, van der Waals attractive, and short-range repulsive energies. The summation of the non-bonded energy terms at equally-spaced grid points surrounding a mineral substrate provides a three dimensional potential energy grid. The energy map can be used to determine the optimal sorption sites of metal ions on the exposed surfaces of the mineral. By using this approach, we have evaluated the crystallographic and compositional control of metal sorption on the surfaces of kaolinite and illite. Estimates of the relative sorption energy and most stable sorption sites are derived based on a rigid ion approximation

  11. Applicability of microautoradiography to sorption studies

    International Nuclear Information System (INIS)

    Thompson, J.L.; Wolfsberg, K.

    1979-01-01

    The technique of microautoradiography was applied to the study of the sorption of uranium and americium on five rock types which exist at the Nevada Test Site. It was found that autoradiograms could be prepared in a few days which would allow the specific minerals responsible for sorption to be identified. Furthermore, the state of aggregation of the sorbed species was clearly indicated. It was concluded that microautoradiography was a useful adjunct to currently used methods for studying sorption of certain radionuclides

  12. Time-dependent sorption of two novel fungicides in soils within a regulatory framework.

    Science.gov (United States)

    Gulkowska, Anna; Buerge, Ignaz J; Poiger, Thomas; Kasteel, Roy

    2016-12-01

    Convincing experimental evidence suggests increased sorption of pesticides on soil over time, which, so far, has not been considered in the regulatory assessment of leaching to groundwater. Recently, Beulke and van Beinum (2012) proposed a guidance on how to conduct, analyse and use time-dependent sorption studies in pesticide registration. The applicability of the recommended experimental set-up and fitting procedure was examined for two fungicides, penflufen and fluxapyroxad, in four soils during a 170 day incubation experiment. The apparent distribution coefficient increased by a factor of 2.5-4.5 for penflufen and by a factor of 2.5-2.8 for fluxapyroxad. The recommended two-site, one-rate sorption model adequately described measurements of total mass and liquid phase concentration in the calcium chloride suspension and the calculated apparent distribution coefficient, passing all prescribed quality criteria for model fit and parameter reliability. The guidance is technically mature regarding the experimental set-up and parameterisation of the sorption model for the two moderately mobile and relatively persistent fungicides under investigation. These parameters can be used for transport modelling in soil, thereby recognising the existence of the experimentally observed, but in the regulatory leaching assessment of pesticides not yet routinely considered phenomenon of time-dependent sorption. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  13. Effects of aged sorption on pesticide leaching to groundwater simulated with PEARL.

    Science.gov (United States)

    Boesten, Jos J T I

    2017-01-15

    Leaching to groundwater is an important element of the regulatory risk assessment of pesticides in western countries. Including aged sorption in this assessment is relevant because there is ample evidence of this process and because it leads to a decrease in simulated leaching. This work assesses the likely magnitude of this decrease for four groundwater scenarios used for regulatory purpose in the EU (from the UK, Portugal, Austria and Greece) and for ranges of aged-sorption parameters and substance properties using the PEARL model. Three aged-sorption parameters sets were derived from literature, representing approximately 5th, 50th and 95th percentile cases for the magnitude of the effect of aged sorption on leaching concentrations (called S, M and L, respectively). The selection of these percentile cases was based only on the f NE parameter (i.e. the ratio of the aged sorption and the equilibrium sorption coefficients) because leaching was much more affected by the uncertainty in this parameter than by the uncertainty in the desorption rate coefficient of these sites (k d ). For the UK scenario, the annual flux concentration of pesticide leaching at 1m depth decreased by typically a factor of 5, 30 and >1000 for the S, M and L parameter sets, respectively. This decrease by a factor of 30 for the M parameter set appeared to be approximately valid also for the other three scenarios. Decreasing the Freundlich exponent N from 0.9 into 0.7 for the M parameter set, increased this factor of 30 into a factor of typically 1000, considering all four scenarios. The aged-sorption sites were close to their equilibrium conditions during the leaching simulations for two of the four scenarios (for all substances considered and the M parameter set), but this was not the case for the other two scenarios. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. Sorption of biodegradation end products of nonylphenol polyethoxylates onto activated sludge.

    Science.gov (United States)

    Hung, Nguyen Viet; Tateda, Masafumi; Ike, Michihiko; Fujita, Masanori; Tsunoi, Shinji; Tanaka, Minoru

    2004-01-01

    Nonylphenol(NP), nonylphenoxy acetic acid (NP1EC), nonylphenol monoethoxy acetic acid (NP2EC), nonylphenol monoethoxylate (NP1EO) and nonylphenol diethoxylate (NP2EO) are biodegradation end products (BEPs) of nonionic surfactant nonylphenolpolyethoxylates (NPnEO). In this research, sorption of these compounds onto model activated sludge was characterized. Sorption equilibrium experiments showed that NP, NP1EO and NP2EO reached equilibrium in about 12 h, while equilibrium of NP1EC and NP2EC were reached earlier, in about 4 h. In sorption isotherm experiments, obtained equilibrium data at 28 degrees C fitted well to Freundlich sorption model for all investigated compounds. For NP1EC, in addition to Freundlich, equilibrium data also fitted well to Langmuir model. Linear sorption model was also tried, and equilibrium data of all NP, NP1EO, NP2EO and NP2EC except NP1EC fitted well to this model. Calculated Freundlich coefficient (K(F)) and linear sorption coefficient (K(D)) showed that sorption capacity of the investigated compounds were in order NP > NP2EO > NP1EO > NP1EC approximately NP2EC. For NP, NP1EO and NP2EO, high values of calculated K(F) and K(D) indicated an easy uptake of these compounds from aqueous phase onto activated sludge. Whereas, NP1EC and NP2EC with low values of K(F) and K(D) absorbed weakly to activated sludge and tended to preferably remain in aqueous phase.

  15. Sorption behavior of nonylphenol (NP) on sewage-irrigated soil: Kinetic and thermodynamic studies

    International Nuclear Information System (INIS)

    Liao, Xiaoping; Zhang, Caixiang; Yao, Linlin; Li, Jiale; Liu, Min; Xu, Liang; Evalde, Mulindankaka

    2014-01-01

    The reuse of wastewater for irrigation of agricultural land is a well established resources management practice but has the disadvantage of inputting various forms of contaminants into the terrestrial environment including nonylphenol (NP), a well known endocrine disrupting substance. To elucidate the environmental fate and transport of NP, the sorption behavior on sewage-irrigated soil was studied by batch experiment. It was found that sorption processes of NP on different sorbents (soil, humic acid (HA) and silica) could be expressed well using two compartment pseudo first-order model, where both surface and intra-particle diffusion were probable rate-controlling processes. Linear model could better express the sorption of NP on soil, black carbon (BC) and mineral (e.g., SiO 2 ) except HA than Freundlich model. The large value of distribution coefficients of normalized organic carbon (K oc ) on soils indicated that NP was limited to migrate to deep soil. The higher desorption partition coefficient of NP on soil showed enhanced hysteresis. According to the experimental data, the calculated thermodynamic parameters implied that the sorption reaction on sewage-irrigation was spontaneous, exothermic and entropy decreasing process. The amount of soil organic matter (SOM) dominated the sorption capacity, whereas the sorption behavior of NP on soil showed no significant correlation with ionic strength. - Highlights: • Both surface and intra-particle diffusion were rate-controlling processes. • Soil composition influences the partition activity of NP. • Soil organic matter has dominated the sorption capacity of NP on soil. • NP molecule was limited to migrate to deep soil in sewage-irrigated area

  16. Sorption of Np(V) by synthetic hydroxyapatite

    International Nuclear Information System (INIS)

    Moore, R.C.; Holt, K.; Zhao, H.; Hasan, A.; Awwad, N.; Gasser, M.; Sanchez, C.

    2003-01-01

    The sorption of Np(V) to synthetic hydroxyapatite was determined in batch experiments in a 0.1 M NaClO 4 solution. The hydroxyapatite used was of high purity as determined by SEM, EDS, XRD, FT-IR and ICP-MS analysis. Results from kinetic experiments with an initial Np(V) concentration of 1 x 10 -7 to 1 x 10 -6 M indicate the sorption process is relatively fast with more than 90% of the Np(V) being sorbed in approximately 3 hours. Equilibrium experiments performed over the pH range of 6 to 11 indicated sorption is strongly pH dependent with distribution coefficients, K d values (mL/g), increasing from 123 L/mole at pH 6 to 69 200 L/mole at pH 8.5. K d values are observed to decrease as pH further increases. Data points over a range of Np(V) concentrations were collected at pH 8 and fitted to the Langmuir isotherm model for simple adsorption. The Langmuir equation gave an excellent representation of the data. Langmuir parameters were determined to be C a = 0.032 mole/mole and K = 1.22 x 10 6 L/mole, indicating the high affinity of hydroxyapatite for Np(V) adsorption. (orig.)

  17. Strontium sorption on Savannah River Plant soils

    International Nuclear Information System (INIS)

    Hoeffner, S.L.

    1984-12-01

    A laboratory study of strontium-85 sorption was conducted using Savannah River Plant soil and groundwater from the low-level waste burial ground. Systematic variation of soil and water composition indicates that strontium sorption is most strongly a function of pH. Changes in clay content and in K + , Ca 2+ , or Mg 2+ concentrations influence strontium sorption indirectly through the slight pH changes which result. The ions Na + , Cl - , and NO 3 - have no effect. Ferrous ion, added to groundwater to simulate the conditions of water at the bottom of waste trenches, did not account for low strontium sorption observed with some trench waters

  18. Effect of competing cations on strontium sorption to surficial sediments

    International Nuclear Information System (INIS)

    Bunde, R.L.; Rosentreter, J.J.

    1995-01-01

    The following study was conducted to determine strontium distribution coefficients (K d 'S) of a surficial sediment at the Idaho National Engineering Laboratory (INEL), Idaho. Batch experimental techniques were used to determine K d 's which describe the partitioning of a solute between the solution and solid phase. A surficial sediment was mixed with synthesized aqueous solutions designed to chemically simulate wastewater disposed to infiltrations ponds near the Idaho Chemical Processing Plant at the INEL with respect to major ionic character and pH. The effects of variable concentrations of competing cations (sodium, potassium, calcium and magnesium) on strontium sorption were investigated at a fixed pH of 8.00. The pH of the natural system shows no appreciable variation, whereas a marked variability in cation concentration has been noted. Strontium sorption was impacted to a greater degree by the concentration of calcium and magnesium in solution than by the presence of sodium or potassium. However, extreme sodium solution concentrations of 1.0 to 5.0 g/L dramatically reduced strontium sorption. In all cases, strontium K d 's decreased as the concentration of calcium and magnesium in solution increased. Linear isotherm model K d 's ranged from 12.0 to 84.7 mL/g. Analysis of data from these experiments indicated that moderate concentrations of calcium and magnesium (less than 40 mg/L) and high concentrations of sodium (1.0 to 5.0 g/L) in wastewater increase strontium mobility by decreasing the sorption of strontium on surficial sediments beneath infiltration ponds at the INEL

  19. Review of sorption and diffusion data for SR 97

    Energy Technology Data Exchange (ETDEWEB)

    Stenhouse, M. [Monitor Scientific, LLC, Denver, CO (United States)

    2000-12-01

    studied. There is always likely to be a lack of experimental data to support what is effectively expert judgement. Therefore, the best management approach is to focus on those elements for which no data exist (to confirm or update current recommendations, as appropriate), or for radionuclides which appear as key contributors to dose. In the latter case, variation in K{sub d} values can be explored by sensitivity analysis and, where a factor of 10 reduction is significant in terms of a radionuclide's contribution to total dose, experimental work should be carried out. Thus, Andersson's recommendation for probabilistic cases should ensure that any K{sub d} -limiting cases are identified. Radionuclide transport through the bentonite buffer is taken into account via diffusion, with sorption where merited. The input parameters required, therefore, are effective diffusion coefficient, D{sub e}, distribution coefficient, K{sub d} , and porosity, {epsilon}. Andersson notes that the code used by SKB to model migration through the near field can use only one value of porosity, which leads to logistical problems regarding data input. In particular, K{sub d} values must be 'manipulated' to yield a D{sub e} (effective diffusion coefficient) value representative of the transport porosity and the true sorption capacity for that radionuclide. In this regard, comparison of K{sub d} values with other programmes must be treated with caution. For input to the work of Yu and Neretnieks, who provided recommendations on relevant K{sub d} values for sorption on compacted bentonite, the lack of a reference porewater seems a major omission. The omission may well have been influenced by the lack of a consensus in how to establish a reference porewater composition. It is now well established that K{sub d} values obtained from batch sorption experiments must be treated with caution when applying such values to sorption on compacted bentonite. In particular, measurements using

  20. Sorption of radionuclides on inorganic sorbents

    International Nuclear Information System (INIS)

    Rajec, P.; Matel, L.

    1995-01-01

    The sorption of cesium, strontium, plutonium and americium from water solution on natural zeolite, clay minerals, synthetic zeolites and ferrocyanides in silica gel matrix was studied. The same experiments but with synthetic zeolites irradiated by the dose 100 kGy proved no change in sorption properties. 1 tab., 4 refs

  1. Nitrate Sorption in an Agricultural Soil Profile

    Directory of Open Access Journals (Sweden)

    Wissem Hamdi

    2013-01-01

    Full Text Available Increasing concentrations of in surface water and groundwater can cause ecological and public health effects and has come under increased scrutiny by both environmental scientists and regulatory agencies. For many regions though, including the Sahel of Tunisia, little is known about the sorption capacity of soils. In this project we measured sorption by a profile of an iso-humic soil from Chott Meriem, Tunisia. Soil samples were collected from four soil depths (0–25, 25–60, 60–90, and 90–120 cm on 1 June 2011, and their sorption capacity was determined using batch experiments under laboratory conditions. The effects of contact time, the initial concentration, and the soil-solution ratio on sorption were investigated. In general, the results suggested that was weakly retained by the Chott Meriem soil profile. The quantity of sorption increased with depth, contact time, initial concentration, and soil-solution ratios. To evaluate the sorption capacities of the soil samples at concentrations ranging between 25 and 150 mg L−1 experimental data were fitted to both Freundlich and Langmuir isotherm sorption models. The results indicated that Freundlich model was better for describing sorption in this soil profile.

  2. Sorption of mercury on chemically synthesized polyaniline

    International Nuclear Information System (INIS)

    Remya Devi, P.S.; Verma, R.; Sudersanan, M.

    2006-01-01

    Sorption of inorganic mercury (Hg 2+ ) and methyl mercury, on chemically synthesized polyaniline, in 0.1-10N HCl solutions has been studied. Hg 2+ is strongly sorbed at low acidities and the extent of sorption decreases with increase in acidity. The sorption of methyl mercury is very low in the HCl concentration range studied. Sorption of Hg 2+ on polyaniline in 0.1-10N LiCl and H 2 SO 4 solutions has also been studied. The analysis of the data indicates that the sorption of Hg 2+ depends on the degree of protonation of polyaniline and the nature of mercury(II) chloride complexes in solution. X-ray photoelectron spectroscopy analysis (XPS) of polyaniline sorbed with mercury show that mercury is bound as Hg 2+ . Sorbed mercury is quantitatively eluted from polyaniline with 0.5N HNO 3 . Polyaniline can be used for separation and pre-concentration of inorganic mercury from aqueous samples. (author)

  3. Sorption of long-lived radionuclides in clay and rock

    International Nuclear Information System (INIS)

    Allard, B.; Kipatsi, H.; Rydberg, J.

    1977-10-01

    The mechanism of sorption of water soluble species in the natural environment has been discussed. The radiochemical and radiobiological properties of the elements in spent nuclear fuel have been briefly discussed, and 14 of the radioactive products have been selected for studies of the sorption behaviour in contact with natural rock and clay minerals. These 14 elements are Sr, Zr, Tc, I, Cs, Ce, Nd, Eu, Ra, Th, U, Np, Pu and Am. From data available concerning composition and equilibria in natural subsoil waters two standard water compositions have been suggested for the laboratory measurements. Suitable concentrations of the radionuclides and experimental temperatures have been proposed. A batch technique has been used for determination of distribution coefficients for powdered solid materials. Measurements have been performed for all of the 14 elements with granite and bentonite/quartz mixture (10:90) with variation of water composition, nuclide concentration and temperature. Moreover, the effect of variation of the particle size has been studied for granite with Sr, Cs and Am, as well as the sorption in powdered granodiorite, chlorite and silt and on fresh and old rock surfaces (granite). The presence of organic components in bentonite has been confirmed and a preliminary complex formation study with these organics has been performed. An estimation of the valencestate of the actinides U, Np and Pu has been suggested using reasonable assumptions regarding the hydrolysis of the actinides and the presence of Fe(IIE/Fe(IE in natural waters. Using measured or calculated distribution coefficients and considering the chemical properties of the natural water system, relevant retention factors of the radionuclides have been proposed. (author)

  4. A study of specific sorption of neptunium(V) on smectite in low pH solution

    International Nuclear Information System (INIS)

    Kozai, Naofumi; Ohnuki, Toshihiko; Matsumoto, Junko; Banba, Tsunetaka; Ito, Yoshimoto

    1996-01-01

    The 'specific sorption' of neptunium(V) on smectite, in other words, a strong sorption undesorbable by 1 M KCl, is studied with a combination of batch type sorption and desorption experiments over a pH range of 2 to 5. Six types of homoionic smectite (Li-, Na-, K-, Cs-, Mg-, and Ca-smectite) are used in this study. Distribution coefficients (K d ) of neptunium for smectite vary over a wide pH range; the maximum K d value of ∝300 cm 3 x g -1 at around pH 2 for Li- and Na-smectite and the minimum value of ∝2 cm 3 x g -1 for Cs-smectite. The specific sorption of neptunium depends on pH and on the affinity of the exchangeable cation for smectite; the lower the pH of solution or the affinity, the larger the specific sorption. The neptunium-smectite association varies with the elapse of contact time. Within the first day of the neptunium-smectite contact the neptunium sorbed on na-smectite at low pH is desorbable by 1 M KCl solution, and on the passage of time most of the neuptunium sorbed becomes undesorbable by KCl (the specific sorption). Hydronium ion in solution is sorbed on smectite at low pH and dissociates the exchangeable cation from smectite into solution, and the specific sorption of neuptunium increases with increasing the exchangeable cation that is dissociated from smectite. (orig.)

  5. Field-scale predictions of soil contaminant sorption using visible–near infrared spectroscopy

    DEFF Research Database (Denmark)

    Paradelo Pérez, Marcos; Hermansen, Cecilie; Knadel, Maria

    2016-01-01

    . By means of the vis–NIR spectra we were able to predict phenanthrene (R2 = 0.95, RMSECV = 31 L kg−1) and glyphosate (R2 = 0.79, RMSECV = 45 L kg−1) sorption capacities. A model using vis–NIR spectra plus pH values improved the prediction of glyphosate sorption capacity (R2 = 0.88, RMSECV = 34 L kg−1......) and glyphosate (sorbed on mineral fractions). Forty-five bulk soil samples were collected from an agricultural field in Estrup, Denmark, in a 15 m × 15 m grid. Samples were air-dried, sieved to 2 mm and analysed for selected soil properties. Sorption coefficients were obtained from a batch equilibration...

  6. An experimental study on the sorption of U(VI) onto granite

    International Nuclear Information System (INIS)

    Baik, Min Hoon; Hahn, Pil Soo

    2002-01-01

    The sorption of U(VI) on a domestic granite is studied as a function of experimental conditions such as contact time, solution-solid ratio, ionic strength, and pH using a batch procedure. The distribution coefficients, K d 's, of U(VI) are about 1-100mL/g depending on the experimental conditions. The sorption of U(VI) onto granite particles is greatly dependent upon the contact time, solution-solid ratio, and pH, but very little is dependent on the ionic strength. It is noticed that an U(VI)-carbonato ternary surface complex can be formed in the neutral range of pH. In the alkaline range of pH above 7, U(VI) sorption onto granite particles is greatly decreased due to the formation of anionic U(VI)-carbonato aqueous complexes

  7. A literature survey of mineral-specific sorption data on radionuclides with relevance to the disposal of radioactive waste

    International Nuclear Information System (INIS)

    Delakowitz, B.; Meinrath, G.; Spiegel, W.

    1996-01-01

    A comparative review of mineral-specific radionuclide sorption databases created for performance assessment and reported in both the open literature and 'grey literature' (e.g. technical reports) has in part shown poor quality of documentation describing the database selection procedures. Inadequate information is available on the chemical species of the radionuclide under consideration and the laboratory conditions for determining K d -values. Sorption data derived from literature are neither comparable nor generally applicable due to the wide range in the composition of the aqueous and the solid phase applied in migration experiments. Subsequently, standardized characterization and determination procedures are needed. To improve the reliability of a mathematical model for the prediction of radionuclide sorption on cementitious and ash-type binder materials, determination of mineral-specific sorption coefficients is indispensable. (author). 31 refs., 1 fig., 2 tabs

  8. Isolation and characterization of biochar-derived organic matter fractions and their phenanthrene sorption.

    Science.gov (United States)

    Jin, Jie; Sun, Ke; Liu, Wei; Li, Shiwei; Peng, Xianqiang; Yang, Yan; Han, Lanfang; Du, Ziwen; Wang, Xiangke

    2018-05-01

    Chemical composition and pollutant sorption of biochar-derived organic matter fractions (BDOMs) are critical for understanding the long-term environmental significance of biochar. Phenanthrene (PHE) sorption by the humic acid-like (HAL) fractions isolated from plant straw- (PLABs) and animal manure-based (ANIBs) biochars, and the residue materials (RES) after HAL extraction was investigated. The HAL fraction comprised approximately 50% of organic carbon (OC) of the original biochars. Results of XPS and 13 C NMR demonstrated that the biochar-derived HAL fractions mainly consisted of aromatic clusters substituted by carboxylic groups. The CO 2 cumulative surface area of BDOMs excluding PLAB-derived RES fractions was obviously lower than that of corresponding biochars. The sorption nonlinearity of PHE by the fresh biochars was significantly stronger than that of the BDOM fractions, implying that the BDOM fractions were more chemically homogeneous. The BDOMs generally exhibited comparable or higher OC-normalized distribution coefficients (K oc ) of PHE than the original biochars. The PHE logK oc values of the fresh biochars correlated negatively with the micropore volumes due to steric hindrance effect. In contrast, a positive relationship between the sorption coefficients (K d ) of BDOMs and the micropore volumes was observed in this study, suggesting that pore filling could dominate PHE sorption by the BDOMs. The positive correlation between the PHE logK oc values of the HAL fractions and the aromatic C contents indicates that PHE sorption by the HAL fractions was regulated by aromatic domains. The findings of this study improve our knowledge of the evolution of biochar properties after application and its potential environmental impacts. Copyright © 2018 Elsevier Ltd. All rights reserved.

  9. Using fluorescent dyes as proxies to study herbicide removal by sorption in buffer zones.

    Science.gov (United States)

    Dollinger, Jeanne; Dagès, Cécile; Voltz, Marc

    2017-04-01

    The performance of buffer zones for removing pesticides from runoff water varies greatly according to landscape settings, hydraulic regime, and system design. Evaluating the performance of buffers for a range of pesticides and environmental conditions can be very expensive. Recent studies suggested that the fluorescent dyes uranine and sulforhodamine B could be used as cost-effective surrogates of herbicides to evaluate buffer performance. However, while transformation mechanisms in buffers have been extensively documented, sorption processes of both dyes have rarely been investigated. In this study, we measured the adsorption, desorption, and kinetic sorption coefficients of uranine and sulforhodamine B for a diverse range of buffer zone materials (soils, litters, plants) and compared the adsorption coefficients (Kd) to those of selected herbicides. We also compared the global sorption capacity of 6 ditches, characterized by varying proportions of the aforementioned materials, between both dyes and a set of four herbicides using the sorption-induced pesticide retention indicator (SPRI). We found that both the individual Kd of uranine for the diverse buffer materials and the global sorption capacity of the ditches are equivalent to those of the herbicides diuron, isoproturon, and metolachlor. The Kd of sulforhodamine B on plants and soils are equivalent to those of glyphosate, and the global sorption capacities of the ditches are equivalent for both molecules. Hence, we demonstrate for the first time that uranine can be used as a proxy of moderately hydrophobic herbicides to evaluate the performance of buffer systems, whereas sulforhodamine B can serve as a proxy for more strongly sorbing herbicides.

  10. Cesium and strontium sorption by selected tropical and subtropical soils around nuclear facilities

    International Nuclear Information System (INIS)

    Chiang, P.N.; Wang, M. K.; Huang, P.M.; Wang, J.J.; Chiu, C.Y.

    2010-01-01

    The dynamics of Cs and Sr sorption by soils, especially in the subtropics and tropics, as influenced by soil components are not fully understood. The rates and capacities of Cs and Sr sorption by selected subtropical and tropical soils in Taiwan were investigated to facilitate our understanding of the transformation and dynamics of Cs and Sr in soils developed under highly weathering intensity. The Langmuir isotherms and kinetic rates of Cs and Sr sorption on the Ap1 and Bt1 horizons of the Long-Tan (Lt) and the A and Bt1 horizons of the Kuan-Shan (Kt), Mao-Lin (Tml) and Chi-Lo (Cl) soils were selected for this study. Air-dried soil ( -5 to 1.88 x 10 -3 M of CsCl (pH 4.0) or 1.14 x 10 -4 to 2.85 x 10 -3 M of SrCl 2 (pH 4.0) solutions at 25 deg. C. The sorption maximum capacity (q m ) of Cs by the Ap1 and Bt1 horizons of the Lt soil (62.24 and 70.70 mmol Cs kg -1 soil) were significantly (p -1 soil in Kt soil and 34.83 and 29.96 mmol Cs kg -1 soil in Cl soil, respectively), however, the sorption maximum capacity values of the Lt and Tml soils did not show significant differences. The amounts of pyrophosphate extractable Fe (Fe p ) were correlated significantly with the Cs and Sr sorption capacities (for Cs sorption, r 2 = 0.97, p -4 ; for Sr sorption, r 2 = 0.82, p -3 ). The partition coefficient of radiocesium sorbed on soil showed the following order: Cl soil >> Kt soil > Tml soil > Lt soil. It was due to clay minerals. The second-order kinetic model was applied to the Cs and Sr sorption data. The rate constant of Cs or Sr sorption on the four soils was substantiality increased with increasing temperature. This is attributable to the availability of more energy for bond breaking and bond formation brought about by the higher temperatures. The rate constant of Cs sorption at 308 K was 1.39-2.09 times higher than that at 278 K in the four soils. The activation energy of Cs and Sr sorbed by the four soils ranged from 7.2 to 16.7 kJ mol -1 and from 15.2 to 22.4 kJ mol

  11. Sorption of uranyl ions on hydrous oxides

    International Nuclear Information System (INIS)

    Gupta, A.R.; Venkataramani, B.

    1988-01-01

    Sorption of uranyl ions on hydrous titanium oxide (HTiO), magnetite (MAG), and hydrous thorium oxide (HThO) has been studied as a function of pH. Hydrous oxides have been characterized by their pH-titration curves, intrinsic dissociation constants (pK ai * ) and point of zero charge (pH pzc ). The fraction of protonated surface hydroxyl groups as well as the surface pH (pH surf ) as a function of solution pH have been computed. The distribution of various hydrolyzed species of uranyl ions with solution pH have been compared with uranyl sorption isotherm on these oxides. Sorption edge in all the cases occurs when free hydroxyl groups are available on the surface and pH surf is sufficiently high to favor the formation of dimer-like species on the surface. A new model for the sorption process, called surface hydrolysis model, which explains these and other features of uranyl sorption on hydrous oxides has been proposed. The model visualizes the sorption process as linking of uranyl ions with two adjacent free surface hydroxyl groups without deprotonation (provided the surface pH is high for the hydrolysis of uranyl ions) and formation of dimer-like structures on the surface. The new model has been successfully applied to the present and other available data on uranyl ion sorption on hydrous oxides. (author)

  12. Sorption equilibria of ethanol on cork.

    Science.gov (United States)

    Lequin, Sonia; Chassagne, David; Karbowiak, Thomas; Bellat, Jean-Pierre

    2013-06-05

    We report here for the first time a thermodynamic study of gaseous ethanol sorption on raw cork powder and plate. Our study aims at a better understanding of the reactivity of this material when used as a stopper under enological conditions, thus in close contact with a hydroethanolic solution, wine. Sorption−desorption isotherms were accurately measured by thermogravimetry at 298 K in a large range of relative pressures. Sorption enthalpies were determined by calorimetry as a function of loading. Sorption−desorption isotherms exhibit a hysteresis loop probably due to the swelling of the material and the absorption of ethanol. Surprisingly, the sorption enthalpy of ethanol becomes lower than the liquefaction enthalpy as the filling increases. This result could be attributed to the swelling of the material, which would generate endothermic effects. Sorption of SO₂ on cork containing ethanol was also studied. When the ethanol content in cork is 2 wt %, the amount of SO₂ sorbed is divided by 2. Thus, ethanol does not enhance the sorption rate for SO₂ but, on the contrary, decreases the SO₂ sorption activity onto cork, probably because of competitive sorption mechanisms.

  13. Sorption of streptococcus faecium to glass

    International Nuclear Information System (INIS)

    Oerstavik, D.

    1977-01-01

    A method has been developed by which to study the sorption of Streptococcus faecium to soda-lime cover glasses. Conditions were chosen to minimize the influence on sorption of bacterial polymer production, passive sorption being studied rather than attachment mediated by metabolic activities. Sorption of S. faecium increased with increasing temperature (to 50degC), time, and cell concentration, but equilibrium apparently was not reached even after incubation for 8 hours or at a cell concentration of 3 x 10 10 per ml. Sorption increased with solute molarity up to 0.1 M concentration of NaCl and KCl, indicating an effect of the electrical double layers on the apposition of cells to the glass surface. Desorption of bacteria could be obtained after multiple washings of the glasses in buffer or by the action of Tween 80, but not if sorbed bacteria were left in distilled water, various salt solutions, urea, or in suspensions of unlabelled bacteria. It was concluded that sorption occurred as a result of chemical interactions between the glass and the cell surface. Tween 80 at a concentration of 1 per cent inhibited sorption to 26 per cent of buffer controls, 2 M urea was less effective, and 1 M NaCl was without effect. It is suggested that hydrophobic interactions may be of importance in the binding of S. faecium to glass. (author)

  14. Competitive sorption and desorption of heavy metals by individual soil components

    International Nuclear Information System (INIS)

    Covelo, E.F.; Vega, F.A.; Andrade, M.L.

    2007-01-01

    Knowledge of sorption and desorption of heavy metals by individual soil components should be useful for modelling the behaviour of soils of arbitrary composition when contaminated by heavy metals, and for designing amendments increasing the fixation of heavy metals by soils polluted by these species. In this study the competitive sorption and desorption of Cd, Cr, Cu, Ni, Pb and Zn by humified organic matter, Fe and Mn oxides, kaolinite, vermiculite and mica were investigated. Due to the homogeneity of the sorbents, between-metal competition for binding sites led to their preferences for one or another metal being much more manifest than in the case of whole soils. On the basis of k d100 values (distribution coefficients calculated in sorption-desorption experiments in which the initial sorption solution contained 100 mg L -1 of each metal), kaolinite and mica preferentially sorbed and retained chromium; vermiculite, copper and zinc; HOM, Fe oxide and Mn oxide, lead (HOM and Mn oxide also sorbed and retained considerable amounts of copper). Mica only retained sorbed chromium, Fe oxide sorbed cadmium and lead, and kaolinite did not retain sorbed copper. The sorbents retaining the greatest proportions of sorbed metals were vermiculite and Mn oxide, but the ratios of k d100 values for retention and sorption suggest that cations were least reversibly bound by Mn oxide, and most reversibly by vermiculite

  15. Migration behavior and sorption mechanisms of radionuclides in sedimentary sand stones

    International Nuclear Information System (INIS)

    Tanaka, Tadao; Kamiyama, Hideo; Sriyotha, K.

    1993-05-01

    The influence of crushed particle size and weathering of sedimentary rock on migration behavior and sorption mechanisms of 60 Co, 85 Sr and 137 Cs has been investigated by using the fresh sand stones (classified into two particle size ranges of 1 ∼ 3 mm and 2 , KCl, NH 2 OH-HCl, K-oxalate and H 2 O 2 solutions were carried out, to elucidate their dominated sorption mechanisms. Distribution coefficient values of the all three radionuclides, Kds, for the sand stone of 1 ∼ 3 mm was smaller than that of 85 Sr, and the same irreversible sorptions as the selective sorption of Co onto manganese oxides and fixation of Cs by the layer silicate for 60 Co and 137 Cs, respectively. Larger sorbability of the weathered sand stone was explained to be related to an increase of amounts of the effective sorption site, such as cation exchangeable site, calcite, smectite and manganese oxides, which was possibly caused from metamorphism induced by weathering the fresh sand stone. (author)

  16. Examination of competitive lanthanide sorption onto smectites and its significance in the management of radioactive waste

    Energy Technology Data Exchange (ETDEWEB)

    Galunin, Evgeny [Departament de Quimica Analitica, Universitat de Barcelona, Marti i Franques 1-11, 08028 Barcelona (Spain); Alba, Maria D. [Instituto de Ciencia de Materiales de Sevilla, Consejo Superior de Investigaciones Cientificas - Universidad de Sevilla, Av. Americo Vespucio 49, 41092 Sevilla (Spain); Santos, Maria J. [Departamento de Quimica, Universidade Estadual de Londrina, Londrina, PR 86051-990 (Brazil); Abrao, Taufik [Instituto de Ciencia de Materiales de Sevilla, Consejo Superior de Investigaciones Cientificas - Universidad de Sevilla, Av. Americo Vespucio 49, 41092 Sevilla (Spain); Vidal, Miquel, E-mail: miquel.vidal@ub.edu [Departament de Quimica Analitica, Universitat de Barcelona, Marti i Franques 1-11, 08028 Barcelona (Spain)

    2011-02-28

    The competitive effect of La and Lu (analogues of radionuclides appearing in radioactive waste) in the sorption in four smectites was examined. Sorption and desorption distribution coefficients (K{sub d}; K{sub d,des}), and desorption rates (R{sub des}) were determined from batch tests in two media: deionized water and, to consider the influence of cement leachates, 0.02 mol L{sup -1} Ca. The competitive effect was lower when high-affinity sites were available, as in the water medium at the lowest range of initial lanthanide concentration, with high K{sub d} for La and for Lu (5-63 x 10{sup 4} L kg{sup -1}). Lower K{sub d} was measured at higher initial concentrations and in the Ca medium, where Lu showed a stronger competitive effect. This was confirmed by fitting the sorption data to a two-solute Langmuir isotherm. The desorption data indicated that sorption was virtually irreversible for the scenarios with high sorption, with an excellent correlation between K{sub d} and K{sub d,des} (R{sup 2} around 0.9 for the two lanthanides). Assuming that radioactive waste is a mixture of radionuclides, and that Ca ions will be provided by the cement leachates, this would reduce the retention capacity of clay engineered barriers.

  17. Sorption of lead onto two gram-negative marine bacteria in seawater

    Science.gov (United States)

    Harvey, Ronald W.; Leckie, James O.

    1985-01-01

    Laboratory adsorption experiments performed at environmentally significant lead (Pb) and cell concentrations indicate that the marine bacteria examined have significant binding capacities for Pb. However, the behavior governing Pb sorption onto gram-negative bacteria in seawater may be quite complex. The sorption kinetics appear to involve two distinct phases, i.e., a rapid removal of Pb from solution within the first few minutes, followed by a slow but nearly constant removal over many hours. Also, the average binding coefficient, calculated for Pb sorption onto bacteria and a measure of binding intensity, increases with decreasing sorption density (amounts of bacteria-associated Pb per unit bacterial surface) at low cell concentrations (105 cells ml−1), but decreases with decreasing sorption density at higher cell concentrations (107 cells ml−1). The latter effect is apparently due to the production of significant amounts of extra-cellular organics at high cell concentrations that compete directly with bacterial surfaces for available lead. Lead toxicity and active uptake by marine bacteria did not appear significant at the Pb concentrations used.

  18. Heavy metal sorption by microalgae

    International Nuclear Information System (INIS)

    Sandau, E.; Sandau, P.; Pulz, O.

    1996-01-01

    Viable microalgae are known to be able to accumulate heavy metals (bioaccumulation). Against a background of the increasing environmental risks caused by heavy metals, the microalgae Chlorella vulgaris and Spirulina platensis and their potential for the biological removal of heavy metals from aqueous solutions were taken as an example for investigation. Small-scale cultivation tests (50 l) with Cd-resistant cells of Chlorella vulgaris have shown that approx. 40% of the added 10 mg Cd/l was removed from the solution within seven days. At this heavy metal concentration sensitive cells died. Non-viable microalgae are able to eliminate heavy metal ions in a short time by biosorption in uncomplicated systems, without any toxicity problems. Compared with original biomasses, the sorption capacity of microalgal by-products changes only insignificantly. Their low price makes them economical. (orig.)

  19. Metal Sorption to Dolomite Surfaces

    International Nuclear Information System (INIS)

    Brady, P.V.; Papenguth, H.W.; Kelly, J.W.

    1999-01-01

    Potential human intrusion into the Waste Isolation Pilot Plant (WIPP) might release actinides into the Culebra Dolomite where sorption reactions will affect of radiotoxicity from the repository. Using a limited residence time reactor the authors have measured Ca, Mg, Nd adsorption/exchange as a function of ionic strength, P CO2 , and pH at 25 C. By the same approach, but using as input radioactive tracers, adsorption/exchange of Am, Pu, U, and Np on dolomite were measured as a function of ionic strength, P CO2 , and pH at 25 C. Metal adsorption is typically favored at high pH. Calcium and Mg adsorb in near-stoichiometric proportions except at high pH. Adsorption of Ca and Mg is diminished at high ionic strengths (e.g., 0.5M NaCl) pointing to association of Na + with the dolomite surface, and the possibility that Ca and Mg sorb as hydrated, outer-sphere complexes. Sulfate amplifies sorption of Ca and Mg, and possibly Nd as well. Exchange of Nd for surface Ca is favored at high pH, and when Ca levels are low. Exchange for Ca appears to control attachment of actinides to dolomite as well, and high levels of Ca 2+ in solution will decrease Kds. At the same time, to the extent that high P CO2 increase Ca 2+ levels, JK d s will decrease with CO 2 levels as well, but only if sorbing actinide-carbonate complexes are not observed to form (Am-carbonate complexes appear to sorb; Pu-complexes might sorb as well; U-carbonate complexation leads to desorption). This indirect CO 2 effect is observed primarily at, and above, neutral pH. High NaCl levels do not appear to affect to actinide K d s

  20. Sorption of methylxanthines by different sorbents

    Science.gov (United States)

    Dmitrienko, S. G.; Andreeva, E. Yu.; Tolmacheva, V. V.; Terent'eva, E. A.

    2013-05-01

    Sorption of caffeine, theophylline, theobromine, diprophylline, and pentoxyphylline on different sorbents (supercross-linked polystyrene, surface-modified copolymer of styrene and divinylbenzene Strata-X, and carbon nanomaterials Taunit and Diasorb-100-C16T) was studied in a static mode in an effort to find new sorbents suitable for sorption isolation and concentration of methylxanthines. The peculiarities of sorption of methylxanthines were explained in relation to the solution acidity, the nature of the sorbates and their concentration, the nature of the solvent, and the structural characteristics of the sorbents.

  1. Sorption isolation of strontium from seawater

    International Nuclear Information System (INIS)

    Avramenko, V.A.; Zheleznov, V.V.; Kaplun, E.V.; Sokol'nitskaya, T.A.; Yukhkam, A.A.

    2001-01-01

    Sorption isolation of strontium from seawater is considered and prospects of use of selective adsorbents for purification of seawater or liquid radioactive wastes mixed with seawater from 90 Sr are discussed. Comparative analysis of sorptive properties of adsorbents of different nature is done. It is shown that sorption-reagent materials developed by authors can to afford effective separation of 90 Sr from seawater. Possible mechanism of strontium sorption by these adsorbents is considered. The prospect of their use for purification of liquid radioactive wastes from strontium is shown [ru

  2. Calcium silicate hydrate: Crystallisation and alkali sorption

    International Nuclear Information System (INIS)

    Hong, S.

    2000-01-01

    Homogeneous single C-S-H gels has been prepared for the investigation of alkali binding potential and crystallisation. A distribution coefficient, R d , was introduced to express the partition of alkali between solid and aqueous phases at 25 deg. C. R d is independent of alkali hydroxide concentration and depends only on Ca:Si ratio over wide ranges of alkali concentration. The trend of numerical values of R d indicates that alkali bonding into the solid improves as its Ca:Si ratio decreases. Reversibility is demonstrated, indicating a possibility of constant R d value of the material. Al has been introduced to form C-A-S-H gels and their alkali sorption properties also determined. Al substituted into C-S-H markedly increases R d , indicating enhancement of alkali binding. However, the dependence of R d on alkali concentration is non-ideal with composition. A two-site model for bonding is presented. Crystallisation both under saturated steam and 1 bar vapour pressure has been investigated. It has been shown that heat treatment by saturated steam causes crystallisation of gels. The principal minerals obtained were (i) C-S-H gel and Ca(OH) 2 at -55 deg. C, (ii) 1.1 nm tobermorite, jennite and afwillite at 85 -130 deg. C, and (iii) xonotlite, foshagite and hillebrandite at 150-180 deg. C. Properties of crystalline C-S-H were also reported for reversible phase transformation, pH conditioning ability, seeding effect and solubility. At 1 bar pressure, crystallisation is slower than in saturated steam due to lower water activity. Tobermorite-like nanodomains develop during reaction at low Ca/Si ratios. In some Ca-rich compositions, Ca(OH) 2 is exsolved and occurs as nano-sized crystallites. (author)

  3. Modelling of niobium sorption on clay minerals in sodium and calcium perchlorate solutions

    Energy Technology Data Exchange (ETDEWEB)

    Ervanne, Heini; Hakanen, Martti; Lehto, Jukka [Helsinki Univ. (Finland). Laboratory of Radiochemistry

    2014-11-01

    The sorption behaviour of niobium on kaolinite and illite minerals in sodium and calcium perchlorate solutions was evaluated with use of the mass distribution coefficient, Rd, obtained in batch sorption experiments. Very high distribution coefficient values, about 100 m{sup 3}/kg, were obtained for both minerals in the neutral pH range between 6 and 8. Values were somewhat lower at pH 5. In NaClO{sub 4} solution, the sorption of niobium starts to decrease at pH higher than 8. This is in agreement with the increase, with pH, in the proportion of anionic niobate species, which are presumed to be low or non-sorbing. A similar decrease was not observed in Ca(ClO{sub 4}){sub 2} solution, probably owing to the influence of Ca on niobium solution speciation and surface species. The surface complexation model was applied to model the Rd values. The model fitted well for the NaClO{sub 4} solution but only at pH below 9 for the Ca(ClO{sub 4}){sub 2} solution. The discrepancy between the strong sorption of niobium in calcium-bearing solution at high pH and the calculated speciation is due in part to the non-inclusion of calcium niobate solution species and Ca-Nb compounds in the present NEA and other similar thermodynamic databases.

  4. Thermodynamic parameters of U (VI) sorption onto soils in aquatic systems.

    Science.gov (United States)

    Kumar, Ajay; Rout, Sabyasachi; Ghosh, Malay; Singhal, Rakesh Kumar; Ravi, Pazhayath Mana

    2013-01-01

    The thermodynamic parameters viz. the standard free energy (∆Gº), Standard enthalpy change (∆Hº) and standard entropy change (∆Sº) were determined using the obtained values of distribution coefficient (kd) of U (VI) in two different types of soils (agricultural and undisturbed) by conducting a batch equilibrium experiment with aqueous media (groundwater and deionised water) at two different temperatures 25°C and 50°C. The obtained distribution coefficients (kd) values of U for undisturbed soil in groundwater showed about 75% higher than in agricultural soil at 25°C while in deionised water, these values were highly insignificant for both soils indicating that groundwater was observed to be more favorable for high surface sorption. At 50°C, the increased kd values in both soils revealed that solubility of U decreased with increasing temperature. Batch adsorption results indicated that U sorption onto soils was promoted at higher temperature and an endothermic and spontaneous interfacial process. The high positive values of ∆Sº for agricultural soil suggested a decrease in sorption capacity of U in that soil due to increased randomness at solid-solution interface. The low sorption onto agricultural soil may be due to presence of high amount of coarse particles in the form of sand (56%). Geochemical modeling predicted that mixed hydroxo-carbonato complexes of uranium were the most stable and abundant complexes in equilibrium solution during experimental.

  5. Carbon dioxide sorption on EDTA modified halloysite

    Directory of Open Access Journals (Sweden)

    Waszczuk Patrycja

    2016-01-01

    Full Text Available In this paper the sorption study of CO2 on EDTA surface modified halloysite was conducted. In the paper chemical modification of halloysite from the Dunino deposit (Poland and its influence on sorption of CO2 are presented. A halloysite samples were washed with water-EDTA 1% solution, centrifuged to separate liquid and impurities and dried. The samples were tested for the sorption capacity using a manometric method with pressure up to 3 MPa. A Langmuir adsorption model was fitted to the data. The results showed that EDTA had a limited effect on the increase of sorption potential at low pressure and the samples exhibited similar results to that ones treated solely with the water solution.

  6. Sorption of metaldehyde using granular activated carbon

    Directory of Open Access Journals (Sweden)

    S. Salvestrini

    2017-09-01

    Full Text Available In this work, the ability of granular activated carbon (GAC to sorb metaldehyde was evaluated. The kinetic data could be described by an intra-particle diffusion model, which indicated that the porosity of the sorbent strongly influenced the rate of sorption. The analysis of the equilibrium sorption data revealed that ionic strength and temperature did not play any significant role in the metaldehyde uptake. The sorption isotherms were successfully predicted by the Freundlich model. The GAC used in this paper exhibited a higher affinity and sorption capacity for metaldehyde with respect to other GACs studied in previous works, probably as a result of its higher specific surface area and high point of zero charge.

  7. Study of sorption of technetium on pyrrhotine

    International Nuclear Information System (INIS)

    Shen Dong; Fan Xianhua; Su Xiguang; Zeng Jishu

    2001-01-01

    The sorption behaviors of technetium on pyrrhotine are studied with batch experiment and dilute sulfuric acid is used to dissolve the technetium adsorbed on pyrrhotine. Sorption and desorption experiment are performed under aerobic and anaerobic conditions (inert gas box). The results show that a significant sorption of technetium on pyrrhotine is found under aerobic and anaerobic conditions, and the sorption on the mineral is supposed to be due to the reduction of TcO 4 - to insoluble TcO 2 ·nH 2 O. Desorption process of the sorbed technetium into dilute sulfuric acid is found to be different under aerobic and anaerobic conditions. On addition of H 2 O 2 to the leach solution a sudden increase of the technetium concentration is observed

  8. Radionuclide sorption on granitic drill core material

    International Nuclear Information System (INIS)

    Eriksen, T.E.; Locklund, B.

    1987-11-01

    Distribution ratios were determined for Sr-85, Cs-134 and Eu-152 on crushed granite and fissure coating/filling material from Stripa mines. Measurements were also carried out on intact fissure surfaces. The experimental data for Sr-85, Cs-134 on crushed material can be accomodated by a sorption model based on the assumption that the crushed material consists of porous spheres with outer and inner surfaces available for sorption. In the case of Eu-152 only sorption on the outer surfaces of the crushed material was observed. The absence of sorption on inner surfaces is most probably due to high depletion of the more strongly sorbed Eu-152 in the water phase and very low diffusivity of Eu-152 in the sorbed state. (orig./HP)

  9. Sorption of heteropoly acids by polyurethane foam

    International Nuclear Information System (INIS)

    Dmitreinko, S.G.; Goncharova, L.V.; Runov, V.K.; Zakharov, V.N.; Aslanova, L.A.

    1997-01-01

    Sorption of oxidized and reduced forms of molybdosilicic, molybdophosphoric and molybdovanadophosphoric acids by polyurethane foam based on ethers and esters is studied. On the basis of sorption dependence on solution pH, polyurethane foam type and spectral characteristics of sorbates the suggestion has been made that in the polyurethane foam phase there are two main types of sorbent-sorbate interaction: electrostatic (ion-ion) and with hydrogen bond formation: and it is impossible to determine the contribution of every interaction

  10. Sorption of organophosphate esters by carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Wei; Yan, Li [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085 (China); Duan, Jinming [School of Environmental and Municipal Engineering, Xi’an University of Architecture and Technology, Xi’an 710055 (China); Jing, Chuanyong, E-mail: cyjing@rcees.ac.cn [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085 (China)

    2014-05-01

    Graphical abstract: The interfacial interactions between the OPE molecules and CNTs. - Highlights: • Oxygen-containing groups on CNTs change the sorption property for OPEs. • Molecular configuration of OPEs has insignificant impact on their sorption. • Hydrophobic, π–π EDA and Brønsted acid–base interaction occurred between the CNTs and OPEs. - Abstract: Insights from the molecular-level mechanism of sorption of organophosphate esters (OPEs) on carbon nanotubes (CNTs) can further our understanding of the fate and transport of OPEs in the environment. The motivation for our study was to explore the sorption process of OPEs on multi-walled CNTs (MWCNTs), single-walled CNTs (SWCNTs) and their oxidized counterparts (O-MWCNTs and O-SWCNTs), and its molecular mechanism over a wide concentration range. The sorption isotherm results revealed that the hydrophobicity of OPEs dominated their affinities on a given CNT and the π–π electron donor–acceptor (EDA) interaction also played an important role in the sorption of aromatic OPEs. This π–π EDA interaction, verified with Raman and FT-IR spectroscopy, could restrict the radial vibration of SWCNTs and affect the deformation vibration γ(CH) bands of OPE molecules. The OPE surface coverage on CNTs, estimated using the nonlinear Dubinin–Ashtakhov model, indicated that the oxygen-containing functional groups on CNTs could interact with water molecules by H-bonding, resulting in a decrease in effective sorption sites. In addition, FTIR analysis also confirmed the occurrence of Brønsted acid–base interactions between OPEs and surface OH groups of SWCNTs. Our results should provide mechanistic insights into the sorption mechanism of OPE contaminants on CNTs.

  11. Sorption of fomesafen in Brazilian soils

    OpenAIRE

    Silva,G.R.; D'Antonino,L.; Faustino,L.A.; Silva,A.A.; Ferreira,F.A.; Texeira,C.C.

    2013-01-01

    The study of the dynamics of a herbicide in the soil focus on the interactions with environmental components to obtain agronomic efficiency, ensuring selectivity to the culture and risk reduction of environmental impact. This study evaluated the sorption process of fomesafen in the Brazilian soils Ultisol, Cambisol, and Organosol. Besides soil, washed sand was used as an inert material for determination of the sorption ratio of fomesafen in the soil. The bioassay method was applied, using Sor...

  12. Kinetics of strontium sorption in calcium phosphate

    International Nuclear Information System (INIS)

    Bacic, S.; Komarov, V.F.; Vukovic, Z.

    1989-01-01

    Kinetics of strontium sorption by highly dispersed solids: tricalcium phosphate (Ca 3 (PO 4 ) 2 , TCP) and hydroxyapatite (Ca 5 (PO 4 ) 3 )H, HAP) were investigated. Analysis of sorption data was made taking into consideration composition and morphology of ultra micro particles. Conclusion is that the isomorphous strontium impurity is structurally sensitive element for calcium phosphate. It was determined that the beginning of strontium desorption corresponds to the beginning of transformation of the TCP - HAP (author)

  13. Radionuclide sorption and migration studies of getters for backfill barriers

    International Nuclear Information System (INIS)

    Nowak, E.J.

    1980-07-01

    Bentonite and hectorite clay minerals were chosen for study and development as potential backfill materials for testing in the proposed Waste Isolation Pilot Plant (WIPP), a radioactive waste repository and test facility in bedded salt. This choice of materials was based on initial screening results which are presented and on the predicted physical properties of these materials. These properties were verified experimentally in concentrated brines specific to the WIPP site. Distribution coefficients, K/sub d/, were calculated from batch sorption measurements on bentonite and hectorite in the nearly saturated brines A and B. The resulting K/sub d/ values were in the range of (1 to 5) x 10 3 ml/g for europium; (2 to 40) x 10 3 ml/g for plutonium(IV); and (4 to 16) x 10 3 ml/g for americium(III). A silica- and calcite-containing sand mixed with bentonite and hectorite acted as a sorber of americium(III) but was merely an inert diluent for plutonium(IV). Pertechnetate anions (TcO 4 - ) sorbed on activated charcoal with K/sub d/ values in the range of (0.2 to 0.4) x 10 3 ml/g. Pertechnetate, cesium, and strontium ions in brine were not sorbed appreciably by bentonite or hectorite. Although experimental evidence is given for a possible role of solubility in the sorption of europium on getters, other data presented here and evidence from the literature are inconsistent with a simple single reaction sorption mechanism. It is concluded that a backfill containing bentonite on hectorite and activated charcoal is potentially an effective barrier to the migration of Eu(III), Pu(IV), and Am(III) cations and, with further development, to the migration of TcO 4 - anions as well

  14. Distribution coefficients for plutonium and americium on particulates in aquatic environments

    International Nuclear Information System (INIS)

    Sanchez, A.L.; Schell, W.R.; Sibley, T.H.

    1982-01-01

    The distribution coefficients of two transuranic elements, plutonium and americium, were measured experimentally in laboratory systems of selected freshwater, estuarine, and marine environments. Gamma-ray emitting isotopes of these radionuclides, 237 Pu and 241 Am, were significantly greater than the sorption Ksub(d) values, suggesting some irreversibility in the sorption of these radionuclides onto sediments. The effects of pH and of sediment concentration on the distribution coefficients were also investigated. There were significant changes in the Ksub(d) values as these parameters were varied. Experiments using sterilized and nonsterilized samples for some of the sediment/water systems indicate possible bacterial effects on Ksub(d) values. (author)

  15. Iodine sorption by microwave irradiated hydrotalcites

    Energy Technology Data Exchange (ETDEWEB)

    Paredes, S.P. [Universidad Autonoma de Puebla, Facultad de Ciencias Quimicas, C.P. 72570, Puebla, Pue (Mexico); Instituto Politecnico Nacional, ESIQIE, C.P. 07738, Mexico, D.F. (Mexico); Fetter, G. [Universidad Autonoma de Puebla, Facultad de Ciencias Quimicas, C.P. 72570, Puebla, Pue (Mexico)]. E-mail: geolarfetter@yahoo.com.mx; Bosch, P. [Universidad Nacional Autonoma de Mexico, Instituto de Investigaciones en Materiales, C.P. 04510, Mexico, D.F. (Mexico); Bulbulian, S. [Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, C.P. 11801, Mexico, D.F. (Mexico)

    2006-12-15

    Mg-Al hydrotalcite-like compounds (HT) were prepared by the microwave method on the one hand with ethoxide-acetylacetonate and on the other with acetylacetonate as precursors. They presented a maximum sorption capacity of 2.179 and 1.517 meq of {sup 131}I{sup -}/g of hydrotalcite respectively. When the hydrotalcites were calcined and rehydrated in a {sup 131}I{sup -} solution, iodine sorption decreased in both samples to 1.515 and 1.446, respectively. The corresponding value for nitrated hydrotalcite which was prepared by the conventional method for comparison purposes, was 0.570. The radionuclide content in hydrotalcites was determined by {gamma}-spectrometry. {sup 131}I{sup -} sorption is dependent on two main parameters: one is the type of the interlayer organic material and the second the surface area. It was found that hydrotalcites prepared with ethoxide-acetylacetonate were better sorbents for {sup 131}I{sup -} than those with acetylacetonate. Still, if the specific surface area increased, {sup 131}I{sup -}sorption increased as well; nitrated HT resulted in low specific surface area and a low sorption capacity. It is, therefore, concluded that organic residues present in the samples prepared by the microwave method favor the sorption of radioactive anions, in particular {sup 131}I{sup -} if compared with nitrated and/or carbonate interlayered hydrotalcites.

  16. Migration and sorption phenomena in packaged foods.

    Science.gov (United States)

    Gnanasekharan, V; Floros, J D

    1997-10-01

    Rapidly developing analytical capabilities and continuously evolving stringent regulations have made food/package interactions a subject of intense research. This article focuses on: (1) the migration of package components such as oligomers and monomers, processing aids, additives, and residual reactants in to packaged foods, and (2) sorption of food components such as flavors, lipids, and moisture into packages. Principles of diffusion and thermodynamics are utilized to describe the mathematics of migration and sorption. Mathematical models are developed from first principles, and their applicability is illustrated using numerical simulations and published data. Simulations indicate that available models are system (polymer-penetrant) specific. Furthermore, some models best describe the early stages of migration/sorption, whereas others should be used for the late stages of these phenomena. Migration- and/or sorption-related problems with respect to glass, metal, paper-based and polymeric packaging materials are discussed, and their importance is illustrated using published examples. The effects of migrating and absorbed components on food safety, quality, and the environment are presented for various foods and packaging materials. The impact of currently popular packaging techniques such as microwavable, ovenable, and retortable packaging on migration and sorption are discussed with examples. Analytical techniques for investigating migration and sorption phenomena in food packaging are critically reviewed, with special emphasis on the use and characteristics of food-simulating liquids (FSLs). Finally, domestic and international regulations concerning migration in packaged foods, and their impact on food packaging is briefly presented.

  17. Sorption of a branched nonylphenol isomer and perfluorooctanoic acid on geosorbents and carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Li, Chengliang

    2011-10-13

    As metabolites of organic surfactants, both nonylphenol (NP) and perfluorooctanoic acid (PFOA) are toxic and ubiquitous in the environment. Their sorption on soils and sediments is of importance for their fate and transport in the environment. Especially in China, there is still a lack of consolidated knowledge on the sorption behavior of NP and PFOA on geosorbents such as Yangtze River sediments. Thus, the present thesis investigates the sorption of a branched NP isomer [4-(1-ethyl-1, 3-dimethylpentyl) phenol] (NP111) and PFOA on Yangtze River sediments and their model components, i.e. a clay mineral (illite), metal oxides (goethite and {delta}-Al{sub 2}O{sub 3}) and organic matter (isolated from Yangtze River sediments and commercial organic matter) by both batch and dialysis techniques. NP111 is the most environmentally relevant NP isomer and its fate in the environment is unknown. Because PFOA is weakly adsorbed on geosorbents, multi-walled carbon nanotubes (MWCNTs) were studied as promising adsorbents. One of the MWCNTs studied contained traces of metal catalyst on the outer surface. Sorption isotherms of NP111 and PFOA on the sediments and their model components were fitted well by the Freundlich model. Sorption of NP111 on the sediments depended largely on their organic carbon content, resulting in organic carbon-normalized sorption coefficient (K{sub OC}) values between 6.3 x 10{sup 3} and 1.1 x 10{sup 4} L kg{sup -1}. The sorption of NP111 on {delta}-Al{sub 2}O{sub 3} and illite was comparable to that on sediments, but significantly lower than that on goethite. In contrast, the sorption of PFOA on the sediments was significantly lower. The affinity of PFOA to goethite and {delta}-Al{sub 2}O{sub 3} was slightly higher than to the sediments, but it was negligible to natural organic matter and illite. The results suggest that the organic carbon content of the sediments plays a dominant role in the sorption of NP111, whereas goethite acts as a potential sink

  18. Influence of sorption competition on sorption data for MX-80 bentonite used in performance assessment

    International Nuclear Information System (INIS)

    Bradbury, M.H.; Baeyens, B.; Marques Fernandes, M.

    2012-01-01

    Document available in extended abstract form only. In order to obtain a (quasi) mechanistic understanding of radionuclide uptake on clay minerals and argillaceous rocks, the majority of sorption experiments have been carried out on purified clay minerals such as montmorillonite and illite at trace concentrations (sorption edges), or as a function of concentration (sorption isotherms), with a single radionuclide under well-defined conditions in simple background electrolytes. As a result of such studies the 2 site proto-lysis non electrostatic surface complexation cation exchange (2SPNE SC/CE) sorption model, was developed and has been successfully applied to quantitatively describe the uptake of numerous radionuclides of differing valences as a function of pH and concentration on montmorillonite. In a deep geological repository for high level waste, stable impurities arise from many sources: they are present in the pore waters, in the tunnel back fill materials and host rock formations, they arise from the corrosion of the carbon steel canister and finally they are dissolved from the spent fuel and vitrified high level waste simultaneously with the radionuclides. These impurities, which are an integral part of a realistic repository system, can potentially compete with radionuclides for the sorption sites on the backfill materials and host rock and thus reduce their uptake on them. The influence of competitive sorption is not intrinsically included (or only partly so) in the sorption model. It is clearly an inherently important issue to quantify the influence of sorption competition on the transport of released radionuclides through the multi-barrier system in a deep repository. In this study an extreme case of a competitive sorption scenario in the near field of a HLW repository is presented. Two factors are considered: one associated with the high concentrations and the other with competitive sorption effects. The tendency in both cases is to cause a reduction in

  19. Neptunium(V) sorption on kaolinite

    Energy Technology Data Exchange (ETDEWEB)

    Amayri, S.; Jermolajev, A.; Reich, T. [Mainz Univ. (Germany). Inst. of Nuclear Chemistry

    2011-07-01

    The sorption behavior of neptunium(V) onto the clay mineral kaolinite was studied in batch experiments under different experimental conditions: [Np(V)] = 7 x 10{sup -12}-8 x 10{sup -6} M, solid-to-liquid ratio 2-20 g L{sup -1}, I = 0.1 and 0.01 M NaClO{sub 4}, pH = 6-10, ambient air and Ar atmosphere. The short-lived isotope {sup 239}Np (T{sub 1/2} = 2.36 d) was used instead of {sup 237}Np (T{sub 1/2} = 2.14 x 10{sup 6} a) to study the sorption behavior of Np(V) at environmentally-relevant concentrations, i.e., 7 x 10{sup -12} M Np. In addition, {sup 239}Np(V) served as tracer to measure sorption isotherms over six orders of magnitude in Np concentration (4.8 x 10{sup -12}-1.0 x 10{sup -4} M). The results show that Np(V) sorption on kaolinite is strongly influenced by pH, CO{sub 2}, and ionic strength. The sorption of 8 x 10{sup -6} M Np(V) at pH 9.0, and ionic strength of 0.1 M NaClO{sub 4} was proportional to the solid-to-liquid ratio of kaolinite in the range of 2-10 g L{sup -1}. In the absence of CO{sub 2}, the Np(V) uptake increased continuously with increasing pH value up to 97% at pH 10. Under ambient CO{sub 2}, the sorption of Np decreased above pH 8 up to zero at pH 10. An increase of Np(V) concentration from 7 x 10{sup -12} to 8 x 10{sup -6} M resulted in a shift of the sorption pH edge by up to one pH unit to higher pH values. The ionic strength influenced the Np(V) sorption onto kaolinite only in the presence of ambient CO{sub 2}. Under Ar atmosphere the sorption of Np(V) was independent from ionic strength, indicating the formation of inner-sphere complexes of Np(V) with kaolinite. Time-dependent batch experiments at pH 9.0 under ambient CO{sub 2} showed that the sorption of Np(V) on kaolinite is fast and fully reversible over six orders in Np(V) concentration. (orig.)

  20. Sorption of cesium on montmorillonite and effect of salt concentration

    International Nuclear Information System (INIS)

    Atun, G.; Bilgin, B.; Mardinli, A.

    1996-01-01

    The sorption behavior of cesium on montmorillonite type[e clay was studied by using radioactivity measurements. Concentrations of Cs + ions ranged from 10 -6 to 10 -2 M. Cesium retention reduced with increasing salt concentration which was varied between 10 -4 and 10 -1 M. Selectivity coefficients K CsNa for the exchange between Cs and Na were calculated for different equivalent fractions of Cs on the solid phase. Using the K CsNa values, free energy change was found to be 7.8 kJ/mol. The data could be fitted to a Freundlich isotherm, and empirical Freundlich parameters enabled the generation of a site distribution function. By fitting the data to the Dubinin-Radushkevich (D-R) isotherm, a mean energy of sorption of 8.6kJ/mole was calculated which corresponds to the energy of ion exchange reactions. The values of energy changes calculated by using two different methods were in good agreement. (author)

  1. Sorption of radionuclides on mesoporous Sn(IV) silicate: a new sorbent

    Energy Technology Data Exchange (ETDEWEB)

    Sepehrian, H. [Jaber Ibn Hayan Research Labs., Nuclear Science and Technology Research Inst., AEOI, Tehran (Iran); Dept. of Applied Chemistry, Univ. of Tarbiat Moallem, Tehran (Iran); Yavari, R.; Ghannadi Maragheh, M. [Jaber Ibn Hayan Research Labs., Nuclear Science and Technology Research Inst., AEOI, Tehran (Iran); Husain, S.W. [Dept. of Applied Chemistry, Univ. of Tarbiat Moallem, Tehran (Iran)

    2008-07-01

    Four different samples of mesoporous Sn(IV) silicate with varying mole ratio of Si/Sn have been used to study the sorption behavior of 18 radionuclides on these materials. Ion-exchange capacity, SEM, distribution coefficient and chemical stability have been studied and discussed. Separation of Tl(I) from Th(IV), Cs(I) from Th(IV) and Cs(I) from Zr(IV) have been developed on columns of this sorbent. (orig.)

  2. Sorption of radionuclides on mesoporous Sn(IV) silicate: a new sorbent

    International Nuclear Information System (INIS)

    Sepehrian, H.; Yavari, R.; Ghannadi Maragheh, M.; Husain, S.W.

    2008-01-01

    Four different samples of mesoporous Sn(IV) silicate with varying mole ratio of Si/Sn have been used to study the sorption behavior of 18 radionuclides on these materials. Ion-exchange capacity, SEM, distribution coefficient and chemical stability have been studied and discussed. Separation of Tl(I) from Th(IV), Cs(I) from Th(IV) and Cs(I) from Zr(IV) have been developed on columns of this sorbent. (orig.)

  3. Biotransformation and sorption of trace organic compounds in biological nutrient removal treatment systems.

    Science.gov (United States)

    Lakshminarasimman, Narasimman; Quiñones, Oscar; Vanderford, Brett J; Campo-Moreno, Pablo; Dickenson, Eric V; McAvoy, Drew C

    2018-05-28

    This study determined biotransformation rates (k bio ) and sorption-distribution coefficients (K d ) for a select group of trace organic compounds (TOrCs) in anaerobic, anoxic, and aerobic activated sludge collected from two different biological nutrient removal (BNR) treatment systems located in Nevada (NV) and Ohio (OH) in the United States (US). The NV and OH facilities operated at solids retention times (SRTs) of 8 and 23 days, respectively. Using microwave-assisted extraction, the biotransformation rates of the chosen TOrCs were measured in the total mixed liquor. Sulfamethoxazole, trimethoprim, and atenolol biotransformed in all three redox regimes irrespective of the activated sludge source. The biotransformation of N, N-diethyl-3-methylbenzamide (DEET), triclosan, and benzotriazole was observed in aerobic activated sludge from both treatment plants; however, anoxic biotransformation of these three compounds was seen only in anoxic activated sludge from NV. Carbamazepine was recalcitrant in all three redox regimes and both sources of activated sludge. Atenolol and DEET had greater biotransformation rates in activated sludge with a higher SRT (23 days), while trimethoprim had a higher biotransformation rate in activated sludge with a lower SRT (8 days). The remaining compounds did not show any dependence on SRT. Lyophilized, heat inactivated sludge solids were used to determine the sorption-distribution coefficients. Triclosan was the most sorptive compound followed by carbamazepine, sulfamethoxazole, DEET, and benzotriazole. The sorption-distribution coefficients were similar across redox conditions and sludge sources. The biotransformation rates and sorption-distribution coefficients determined in this study can be used to improve fate prediction of the target TOrCs in BNR treatment systems. Copyright © 2018. Published by Elsevier B.V.

  4. Sorption of cesium and strontium from concentrated brines by backfill barrier materials

    International Nuclear Information System (INIS)

    Winslow, C.D.

    1981-03-01

    The sorption of radionuclides from potentially intruding groundwater at a nuclear waste repository is a major chemical function of backfill barriers. In this study, various materials (including clays, zeolites and an inorganic ion exchanger) were screened for the sorption of the fission products cesium and strontium in concentrated brines. Representative brines A and B for the Waste Isolation Pilot Plant (WIPP), a proposed radioactive waste repository and test facility in bedded salt were used. Sorption properties were quantified using empirical distribution coefficients, k/sub d/. Of the materials examined, sodium titanate had the highest k/sub d/ for the sorption of Sr(II) in both brine A (k/sub d/ = 125 ml/g) and brine B(k/sub d/ = 500 to 600 ml/g). A mordenite-type zeolite was the most effective getter for Cs(I) in brine A (k/sub d = 27 ml/g), while illite yielded the highest k/sub d/ for Cs(I) in brine B (k/sub d/ = 115 ml/g). The relative merit of these k/sub d/ values is evaluated in terms of calculated estimates of breakthrough times for a backfill barrier containing the getter. Results show that a backfill mixture containing these getters is potentially an effective barrier to the migration of Sr(II) and Cs(I), although further study (especially for the sorption of cesium from brine A) is recommended. Initial mechanistic studies revealed competing ion effects which would support an ion exchange mechanism. K/sub d/'s were constant over a Sr(II) concentration range of 10 -11 to 10 -5 M and a Cs(I) concentration range of 10 -8 to 10 -5 M, supporting the choice of a linear sorption isotherm as a model for the results. Constant batch composition was shown to be attained within one week

  5. Europium sorption on zirconia at elevated temperatures: experimental study and modeling

    International Nuclear Information System (INIS)

    Eglizaud, N.; Catalette, H.

    2005-01-01

    Full text of publication follows: Direct disposal of spent nuclear fuel in deep underground repository is being considered by several countries. The waste package maintains an elevated temperature for thousands of years. As sorption is one of the main phenomenon limiting the dispersion of radionuclides in the environment, it has to be studied at elevated temperatures. Zirconia is an oxide produced by cladding oxidation which is suspected in the near field of a nuclear repository. It then could possibly be in contact with waste elements as Europium (III), the sorption of which is therefore studied on zirconia. Experiments were performed by the batch method at a solid/liquid ratio of 10 g.L-1. The sorption edges were recorded in the pH-range from 2 to 10 at 2.10 -5 mol.L -1 Eu(NO 3 ) 3 (I = 0.1 mol.L -1 KNO 3 ). An over-pressure device in an autoclave with an incorporated filtering system allowed the experiments, carbonate free, at 25 deg. C, 50 deg. C, 80 deg. C, 120 deg. C and 150 deg. C and in situ pH measurements. Filtrates were analyzed by the ICP-AES method. Sorption isotherms show an increase in the sorption phenomenon when the temperature raises. The half sorption pH decreases from 7 at 25 deg. C to 3,6 at 150 deg. C. The distribution coefficients that were obtained at elevated temperatures enriched the databases of integrated performance assessment codes. Raw data were modeled with the surface complexation theory using the double layer model (DLM). Several possible surface complexes were examined and discussed, taking into account aqueous hydrolyzed and precipitated species of Europium. A good agreement between experimental values and modeled isotherms was found at all studied temperatures. Results were consistent with a bidentate complex formed by Europium (III) on the zirconia surface. Associated formation constants were then determined with the geochemical computer code CHESS. (authors)

  6. Sorption of Atrazine in Tropical Soil by Biochar Prepared from Cassava Waste

    Directory of Open Access Journals (Sweden)

    Hui Deng

    2014-09-01

    Full Text Available Biochar (BC is a carbonaceous and porous product generated from the incomplete combustion of biomass and has been recognized as an efficient adsorbent. This study evaluated the ability of BC to sorb atrazine pesticide in tropical soil, and explored potential environmental values of BC on mitigating organic micro-pollutants. BC was produced from cassava waste via pyrolyzation under oxygen-limiting conditions at 350, 550, and 750 °C (MS350, MS550, and MS750, respectively. Three biochars were characterized and investigated as sorbents for the removal atrazine from tropical soil. BC pyrolyzed at higher temperatures more quickly reached equilibrium. The pseudo-second-order model perfectly simulated the sorption kinetics for atrazine with the coefficients R2 above 0.996, and the sorption amount at equilibrium (qe was 0.016 mg/g for MS350, 0.025 mg/g for MS550 and 0.050 mg/g for MS750. The isotherms of MS350 displayed relatively linear behavior, whereas the sorption of atrazine on MS550 and MS750 followed a nonlinear isotherm. The sorption data were well described by the Freundlich model with logKF of 0.476 for MS350, 0.771 for MS550, 1.865 for MS750. A thermodynamic study indicated that the sorption of atrazine in BC-added soil was a spontaneous and endothermic process and was primarily controlled by physisorption. In addition, lower pH was conducive to the sorption of atrazine in BC-added soil.

  7. Sorption kinetics of Cs and Sr in sediments of a Savannah River Site reservoir

    International Nuclear Information System (INIS)

    Stephens, J.A.

    1997-07-01

    Laboratory measurements of the sorption and desorption of 134 Cs and 85 Sr to sediments were conducted. These sediments were sampled from the profundal zone of Par Pond at the Savannah River Site, Aiken, South Carolina. The isotopes 134 Cs and 85 Sr were used to trace the sorption properties of the main contaminants found in the reservoir which are 137 Cs and 90 Sr respectively. The sorption behavior of these two elements was studied using spiked sediment/water slurries of a known mass to volume ratio. The results reveal that Sr undergoes significant reversible sorption while a fraction of Cs irreversibly sorbs to the sediment. The calculated distribution coefficient Kd at equilibrium was (3 ± 0.6) x 10 3 for 134 Cs after 60 d and (1 ± 0.2) x 10 3 for 85 Sr after 7 d at pH ∼ 6 and slurry ratio of 1:1000 g/ml. The K d for 134 Cs ranged from 2 x 10 2 to 3 x 10 4 depending on pH and conductivity. The 85 Sr reached equilibrium in a few days, while 134 Cs reached an apparent equilibrium in 1--2 months. The K d for 134 Cs was a function of the slurry ratio, pH, conductivity, and contact time. These factors were interrelated since the sediments released ions to the slurry mixture which decreased the pH and increased the conductivity. A sorption isotherm measured for 134 Cs was linear at water concentrations from 60 mBq/ml to 20 Bq/ml. A kinetic model was proposed to describe the basic sorption of 134 Cs to Par Pond sediments under homogeneous laboratory conditions

  8. Control of Surface Functional Groups on Pertechnetate Sorption on Activated Carbon

    International Nuclear Information System (INIS)

    Y. Wang; H. Gao; R. Yeredla; H. Xu; M. Abrecht; G.D. Stasio

    2006-01-01

    99 Tc is highly soluble and poorly adsorbed by natural materials under oxidizing conditions, thus being of particular concern for radioactive waste disposal. Activated carbon can potentially be used as an adsorbent for removing Tc from aqueous solutions. We have tested six commercial activated carbon materials for their capabilities for sorption of pertechnetate (TcO 4 - ). The tested materials can be grouped into two distinct types: Type I materials have high sorption capabilities with the distribution coefficients (K d ) varying from 9.5 x 10 5 to 3.2 x 10 3 mL/g as the pH changes from 4.5 to 9.5, whereas type II materials have relatively low sorption capabilities with K d remaining more or less constant (1.1 x 10 3 - 1.8 x 10 3 mL/g) over a similar pH range. The difference in sorption behavior between the two types of materials is attributed to the distribution of surface functional groups. The predominant surface groups are identified to be carboxylic and phenolic groups. The carboxylic group can be further divided into three subgroups A, B, and C in the order of increasing acidity. The high sorption capabilities of type I materials are found to be caused by the presence of a large fraction of carboxylic subgroups A and B, while the low sorption capabilities of type II materials are due to the exclusive presence of phenolic and carboxylic subgroup C. Therefore, the performance of activated carbon for removing TcO 4 - can be improved by enhancing the formation of carboxylic subgroups A and B during material processing

  9. Characterizing the sorption of polybrominated diphenyl ethers (PBDEs) to cotton and polyester fabrics under controlled conditions

    Energy Technology Data Exchange (ETDEWEB)

    Saini, Amandeep [Department of Physical and Environmental Sciences, University of Toronto Scarborough, 1265 Military trail, Toronto, ON M1C 1A4 (Canada); Rauert, Cassandra [School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham B15 2TT (United Kingdom); Simpson, Myrna J. [Department of Physical and Environmental Sciences, University of Toronto Scarborough, 1265 Military trail, Toronto, ON M1C 1A4 (Canada); Harrad, Stuart [School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham B15 2TT (United Kingdom); Diamond, Miriam L., E-mail: miriam.diamond@utoronto.ca [Department of Earth Sciences, 22 Russell Street, University of Toronto, Toronto, ON M5S 3B1 (Canada); Department of Physical and Environmental Sciences, University of Toronto Scarborough, 1265 Military trail, Toronto, ON M1C 1A4 (Canada)

    2016-09-01

    Cotton and polyester, physically and chemically different fabrics, were characterized for sorption of gas-phase polybrominated diphenyl ethers (PBDEs). Scanning electron microscopic (SEM) images and BET specific surface area (BET-SSA) analysis showed cotton's high microsurface area; NMR analysis showed richness of hexose- and aromatic-carbon in cotton and polyester, respectively. Cotton and polyester sorbed similar concentrations of gas-phase PBDEs in chamber studies, when normalized to planar surface area. However, polyester concentrations were 20–50 times greater than cotton when normalized to BET-SSA, greater than the 10 times difference in BET-SSA. The difference in sorption between cotton and polyester is hypothesized to be due to ‘dilution’ due to cotton's large BET-SSA and/or greater affinity of PBDEs for aromatic-rich polyester. Similar fabric-air area normalized distribution coefficients (K'{sub D}, 10{sup 3} to 10{sup 4} m) for cotton and polyester support air-side controlled uptake under non-equilibrium conditions. K'{sub D} values imply that 1 m{sup 2} of cotton or polyester fabrics would sorb gas-phase PBDEs present in 10{sup 3} to 10{sup 4} m{sup 3} of equivalent air volume at room temperature over one week, assuming similar air flow conditions. Sorption of PBDEs to fabrics has implications for their fate indoors and human exposure. - Highlights: • Sorption of gas-phase PBDEs by cotton and polyester fabrics • Similar sorption to cotton and polyester per unit planar surface area • Greater sorption by polyester/BET-SSA; cotton's dilution or polyester’s affinity • 1 m{sup 2} fabric sorbs PBDEs in 10{sup 3} to 10{sup 4} m{sup 3} of equivalent air volume • Clothing likely a large indoor sink of PBDEs and influence human exposure.

  10. Imidacloprid sorption and transport in cropland, grass buffer and riparian buffer soils

    Science.gov (United States)

    Satkowski, Laura E.; Goyne, Keith W.; Anderson, Stephen H.; Lerch, Robert N.; Allen, Craig R.; Snow, Daniel D.

    2018-01-01

    An understanding of neonicotinoid sorption and transport in soil is critical for determining and mitigating environmental risk associated with the most widely used class of insecticides. The objective of this study was to evaluate mobility and transport of the neonicotinoid imidacloprid (ICD) in soils collected from cropland, grass vegetative buffer strip (VBS), and riparian VBS soils. Soils were collected at six randomly chosen sites within grids that encompassed all three land uses. Single-point equilibrium batch sorption experiments were conducted using radio-labeled (14C) ICD to determine solid–solution partition coefficients (Kd). Column experiments were conducted using soils collected from the three vegetation treatments at one site by packing soil into glass columns. Water flow was characterized by applying Br− as a nonreactive tracer. A single pulse of 14C-ICD was then applied, and ICD leaching was monitored for up to 45 d. Bromide and ICD breakthrough curves for each column were simulated using CXTFIT and HYDRUS-1D models. Sorption results indicated that ICD sorbs more strongly to riparian VBS (Kd = 22.6 L kg−1) than crop (Kd = 11.3 L kg−1) soils. Soil organic C was the strongest predictor of ICD sorption (p < 0.0001). The column transport study found mean peak concentrations of ICD at 5.83, 10.84, and 23.8 pore volumes for crop, grass VBS, and riparian VBS soils, respectively. HYDRUS-1D results indicated that the two-site, one-rate linear reversible model best described results of the breakthrough curves, indicating the complexity of ICD sorption and demonstrating its mobility in soil. Greater sorption and longer retention by the grass and riparian VBS soils than the cropland soil suggests that VBS may be a viable means to mitigate ICD loss from agroecosystems, thereby preventing ICD transport into surface water, groundwater, or drinking water resources.

  11. Modeling approaches of competitive sorption and transport of trace metals and metalloids in soils: a review.

    Science.gov (United States)

    Selim, H M; Zhang, Hua

    2013-01-01

    Competition among various heavy metal species for available adsorption sites on soil matrix surfaces can enhance the mobility of contaminants in the soil environment. Accurate predictions of the fate and behavior of heavy metals in soils and geologic media requires the understanding of the underlying competitive-sorption and transport processes. In this review, we present equilibrium and kinetic models for competitive heavy metal sorption and transport in soils. Several examples are summarized to illustrate the impact of competing ions on the reactivities and mobility of heavy metals in the soil-water environment. We demonstrate that equilibrium Freundlich approaches can be extended to account for competitive sorption of cations and anions with the incorporation of competition coefficients associated with each reaction. Furthermore, retention models of the multiple-reaction type including the two-site nonlinear equilibrium-kinetic models and the concurrent- and consecutive-multireaction models were modified to describe commonly observed time-dependent behaviors of heavy metals in soils. We also show that equilibrium Langmuir and kinetic second-order models can be extended to simulate the competitive sorption and transport in soils, although the use of such models is limited due to their simplifying assumptions. A major drawback of the empirically based Freundlich and Langmuir approaches is that their associated parameters are specific for each soil. Alternatively, geochemical models that are based on ion-exchange and surface-complexation concepts are capable of quantifying the competitive behavior of several chemical species under a wide range of environmental conditions. Such geochemical models, however, are incapable of describing the time-dependent sorption behavior of heavy metal ions in competitive systems. Further research is needed to develop a general-purpose model based on physical and chemical mechanisms governing competitive sorption in soils. Copyright

  12. Study of sorption and diffusion of 137Cs in compacted bentonite saturated with saline water at 60degC

    International Nuclear Information System (INIS)

    Suzuki, Satoru; Haginuma, Masashi; Suzuki, Kazunori

    2007-01-01

    The effect of compaction of bentonite on the sorption behavior of 137 Cs was studied for the safety assessment of the high level radioactive waste. The diffusion coefficients (effective D e and apparent D a ) and the distribution coefficient for sorption K d for 137 Cs in compacted and dispersed bentonite saturated with saline water were investigated at 60degC by four different sorption and diffusion experiments: the in-diffusion, through-diffusion, reservoir-depletion and batch sorption experiments. The system of the through-diffusion experiment was carefully designed to maintain the boundary conditions of constant concentration at each end of the specimen. D e and D a were found to be reproducible and showed good consistency among three of the diffusion experiments (through-diffusion, in-diffusion and reservoir depletion). K d of 137 Cs in compacted bentonite determined from the three types of diffusion experiments was in good accordance with that determined by the batch sorption experiment for dispersed bentonite. (author)

  13. Impacts of environmental conditions on the sorption of volatile organic compounds onto tire powder

    International Nuclear Information System (INIS)

    Oh, Dong I.; Nam, Kyongphile; Park, Jae W.; Khim, Jee H.; Kim, Yong K.; Kim, Jae Y.

    2008-01-01

    A series of batch tests were performed and the impacts of environmental conditions and phase change on the sorption of volatile organic compounds (VOCs) were investigated. Benzene, trichloroethylene, tetrachloroethylene, and ethylbenzene were selected as target VOCs. Sorption of VOCs onto tire powder was well demonstrated by a linear-partitioning model. Water-tire partition coefficients of VOCs (not tested in this study) could be estimated using a logarithmic relationship between observed water-tire partition coefficients and octanol-water partition coefficients of the VOCs tested. The target VOCs did not seem to compete with other VOCs significantly when sorbed onto the tire powder for the range of concentrations tested. The influence of environmental conditions, such as pH and ionic strength also did not seem to be significant. Water-tire partition coefficients of benzene, trichloroethylene, tetrachloroethylene, and ethylbenzene decreased as the sorbent dosage increased. However, they showed stable values when the sorbent dosage was greater than 10 g/L. Air-tire partition coefficient could be extrapolated from Henry's law constants and water-tire partition coefficient of VOCs

  14. Impacts of environmental conditions on the sorption of volatile organic compounds onto tire powder

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Dong I. [Division of R and D Planning and Management, Korea Institute of Environmental Science and Technology, Seoul (Korea, Republic of); Nam, Kyongphile [School of Civil, Urban and Geosystem Engineering, College of Engineering, Seoul National University, Gwanak-Ku, 151-742 Seoul (Korea, Republic of); Park, Jae W. [Department of Civil Engineering, Hanyang University, Seoul (Korea, Republic of); Khim, Jee H. [Department of Civil and Environmental Engineering, Korea University, Seoul (Korea, Republic of); Kim, Yong K. [School of Civil, Urban and Geosystem Engineering, College of Engineering, Seoul National University, Gwanak-Ku, 151-742 Seoul (Korea, Republic of); Kim, Jae Y. [School of Civil, Urban and Geosystem Engineering, College of Engineering, Seoul National University, Gwanak-Ku, 151-742 Seoul (Korea, Republic of)], E-mail: jaeykim@snu.ac.kr

    2008-05-01

    A series of batch tests were performed and the impacts of environmental conditions and phase change on the sorption of volatile organic compounds (VOCs) were investigated. Benzene, trichloroethylene, tetrachloroethylene, and ethylbenzene were selected as target VOCs. Sorption of VOCs onto tire powder was well demonstrated by a linear-partitioning model. Water-tire partition coefficients of VOCs (not tested in this study) could be estimated using a logarithmic relationship between observed water-tire partition coefficients and octanol-water partition coefficients of the VOCs tested. The target VOCs did not seem to compete with other VOCs significantly when sorbed onto the tire powder for the range of concentrations tested. The influence of environmental conditions, such as pH and ionic strength also did not seem to be significant. Water-tire partition coefficients of benzene, trichloroethylene, tetrachloroethylene, and ethylbenzene decreased as the sorbent dosage increased. However, they showed stable values when the sorbent dosage was greater than 10 g/L. Air-tire partition coefficient could be extrapolated from Henry's law constants and water-tire partition coefficient of VOCs.

  15. Technetium sorption by stibnite from natural water

    International Nuclear Information System (INIS)

    Peretroukhine, V.; Sergeant, C.; Deves, G.; Poulain, S.; Vesvres, M.H.; Thomas, B.; Simonoff, M.

    2006-01-01

    The sorption of technetium by powdered and polished mineral stibnite Sb 2 S 3 has been investigated in simulated and natural underground waters from the Meuse/Haute-Marne region (France). The sorption by powdered stibnite has been found to be complete under both aerobic and anaerobic conditions in batch experiments. The sorption rate is higher in the absence of oxygen than under aerobic condition. Increasing the temperature from 30 C to 60 C results in a rise of the sorption rate by 9.1 and 27 times under anaerobic and aerobic conditions, respectively. The observed differences in sorption kinetics in the presence and in absence of oxygen are explained by the interaction of oxygen with sulfide ion in aerobic conditions and by the reduction of technetium(VII) by iron(II) and by other impurities present in natural water and in the mineral, and by the subsequent sorption of Tc(IV) on stibnite under anaerobic conditions. The sorption on a polished mineral surface resulted in the formation of a technetium film, probably Tc 2 S 7 , with a thickness of 1-3 μg Tc/cm 2 pH 3-6 and 4-12 μg Tc/cm 2 at 9-12. The simultaneous formation of stibnite colloids with adsorbed technetium occurs at pH 9-12. The study of the technetium film on the mineral by proton induced X-ray emission analysis showed it to be at least one order of magnitude thinner on the SiO 2 impurities than on the main Sb 2 S 3 component and the iron impurities. (orig.)

  16. Kinetic Study of Denatonium Sorption to Smectite Clay Minerals.

    Science.gov (United States)

    Crosson, Garry S; Sandmann, Emily

    2013-06-01

    The denatonium cation, as a benzoate salt, is the most bitter cation known to modern society and is frequently added to consumer products to reduce accidental and intentional consumption by humans and animals. Denatonium can enter the environment by accidental discharges, potentially rendering water supplies undrinkable. Interactions of denatonium with soil components ( i.e. , smectite minerals) ultimately control the environmental fate of denatonium, but the current literature is devoid of studies that evaluate denatonium sorption to smectite minerals. This study investigated the mechanism and kinetics of denatonium sorption to smectite clay minerals as a function of smectite type, temperature, pH and ionic strength. Uptake by synthetic mica montmorillonite (Syn-1), Wyoming montmorillonite (SWy-2), and Texas montmorillonite (STx-1b) at 305K was rapid, with equilibrium being reached within 2 min for all clays. Complete removal of denatonium was observed for STx-1b at pH 6.9, while partial removal was observed for Syn-1 and SWy-2. Kinetic behavior of SWy-2 and Syn-1 is consistent with a pseudo-second-order model at 305K. An activation energy of +25.9 kJ/mol was obtained for sorption to Syn-1 and was independent of temperature between 286K and 338K. Activation-free energy (Δ G *), activation enthalpy (Δ H *), and activation entropy (Δ S *) for Syn-1 were found to be +62.91 kJ/mol, +23.36 kJ/mol, and -0.130 kJ/(K·mol), respectively. Sorption capacities at pH 3.6, 6.9, and 8.2 were constant at 1.3×10 -2 g denatonium/g clay; however, the kinetic rate constant increased by 56%, going from acidic to basic solution conditions. Distribution coefficients were negatively correlated with ionic strength, suggesting cation exchange. Collectively, results suggested that smectite minerals can serve as efficient sinks for denatonium cations. This is much-needed information for agencies developing regulations regarding denatonium usage and for water treatment professionals

  17. Detailed sorption characteristics of the anti-diabetic drug metformin and its transformation product guanylurea in agricultural soils.

    Science.gov (United States)

    Briones, Rowena M; Sarmah, Ajit K

    2018-07-15

    Detection of metformin, an antidiabetic drug and its transformation product guanylurea in various environmental matrices such as surface water and groundwater, coupled with their effects on aquatic organisms warrant an understanding of the compounds fate and behaviour in the environment. Batch studies were conducted with the aim of evaluating the sorption of these two emerging contaminants in six New Zealand agricultural soils of contrasting physico-chemical properties. Kinetic studies revealed that metformin and guanylurea sorption in Te Kowhai soil was very rapid initially achieving 90% sorption within the first 4 and 13h, respectively. Fit of several isotherm models to the measured batch sorption data showed that the hybrid models Langmuir-Freundlich and Redlich-Peterson best described the isotherms. Freundlich isotherm showed higher linearity for guanylurea (n F =0.58-0.93) in all soils compared to metformin (n F =0.25-0.71). A linear isotherm was fitted at environmentally relevant low concentrations (< 3mg/L) of target compounds and calculated values of sorption distribution coefficient (K d ) were in the range of 8.97 to 53.49L/kg for metformin and between 10.6 and 37.51L/kg for guanylurea. Sorption of both metformin and guanylurea was dependent on the soil characteristics, however, no generalisation could be made as to which had higher affinity to soils studied. Pearson's correlation and multiple regression analyses indicate that Si/Al (p=0.042) and clay (p=0.015) significantly influenced metformin K d values, whereas the soil's cation exchange capacity (p=0.024) is the single most significant factor determining guanylurea sorption in soils. It is likely that the type of minerals present in soils and its ion-exchange capacity could play an important role in metformin and guanylurea sorption, respectively. Copyright © 2018. Published by Elsevier B.V.

  18. Characterisation of agricultural waste-derived biochars and their sorption potential for sulfamethoxazole in pasture soil: A spectroscopic investigation

    International Nuclear Information System (INIS)

    Srinivasan, Prakash; Sarmah, Ajit K.

    2015-01-01

    We investigated the effects of feedstock type and pyrolysis temperatures on the sorptive potential of a model pastoral soil amended with biochars for sulfamethoxazole (SMO), using laboratory batch sorption studies. The results indicated that high temperature chars exhibited enhanced adsorptive potential, compared to low temperature chars. Pine sawdust (PSD) biochar produced at 700 °C using the steam gasification process exhibited the highest sorptive capacity (2-fold greater than the control treatment) for SMO among the three biochars used. Soils amended with green waste (GW) biochars produced at three different pyrolysis temperatures showed a small increase in SMO sorption with the increases in temperature. The NMR spectra, the elemental molar ratios (H/C, O/C) and polarity index (O + N)/C of the biochars revealed that PSD biochar possessed the highest degree of aromatic condensation compared to CC and GW chars. These results correlated well with the sorption affinity of each biochar, with effective distribution coefficient (K d eff ) being highest for PSD and lowest for GW biochars. X-ray photoelectron spectroscopy results for the biochars showed a relatively large difference in oxygen containing surface functional groups amongst the GW biochars. However, they exhibited nearly identical sorption affinity to SMO, indicating negligible role of oxygen containing surface functional groups on SMO sorption. These observations provide important information on the use of biochars as engineered sorbents for environmental applications, such as reducing the bioavailability of antibiotics and/or predicting the fate of sulfonamides in biochar-amended soils. - Highlights: • High temperature chars showed enhanced adsorptive potential, compared to low temperature chars. • Oxygen containing acidic functional groups of biochar play negligible role in sorption. • Biochar properties like specific surface area and aromaticity enhanced its sorption capacity. • Amendment of

  19. Characterisation of agricultural waste-derived biochars and their sorption potential for sulfamethoxazole in pasture soil: A spectroscopic investigation

    Energy Technology Data Exchange (ETDEWEB)

    Srinivasan, Prakash; Sarmah, Ajit K., E-mail: a.sarmah@auckland.ac.nz

    2015-01-01

    We investigated the effects of feedstock type and pyrolysis temperatures on the sorptive potential of a model pastoral soil amended with biochars for sulfamethoxazole (SMO), using laboratory batch sorption studies. The results indicated that high temperature chars exhibited enhanced adsorptive potential, compared to low temperature chars. Pine sawdust (PSD) biochar produced at 700 °C using the steam gasification process exhibited the highest sorptive capacity (2-fold greater than the control treatment) for SMO among the three biochars used. Soils amended with green waste (GW) biochars produced at three different pyrolysis temperatures showed a small increase in SMO sorption with the increases in temperature. The NMR spectra, the elemental molar ratios (H/C, O/C) and polarity index (O + N)/C of the biochars revealed that PSD biochar possessed the highest degree of aromatic condensation compared to CC and GW chars. These results correlated well with the sorption affinity of each biochar, with effective distribution coefficient (K{sub d}{sup eff}) being highest for PSD and lowest for GW biochars. X-ray photoelectron spectroscopy results for the biochars showed a relatively large difference in oxygen containing surface functional groups amongst the GW biochars. However, they exhibited nearly identical sorption affinity to SMO, indicating negligible role of oxygen containing surface functional groups on SMO sorption. These observations provide important information on the use of biochars as engineered sorbents for environmental applications, such as reducing the bioavailability of antibiotics and/or predicting the fate of sulfonamides in biochar-amended soils. - Highlights: • High temperature chars showed enhanced adsorptive potential, compared to low temperature chars. • Oxygen containing acidic functional groups of biochar play negligible role in sorption. • Biochar properties like specific surface area and aromaticity enhanced its sorption capacity.

  20. Effects of calcium and magnesium on strontium distribution coefficients

    Science.gov (United States)

    Bunde, R.L.; Rosentreter, J.J.; Liszewski, M.J.; Hemming, C.H.; Welhan, J.

    1997-01-01

    The effects of calcium and magnesium on the distribution of strontium between a surficial sediment and simulated wastewater solutions were measured as part of an investigation to determine strontium transport properties of surficial sediment at the Idaho National Engineering Laboratory (INEL), Idaho. The investigation was conducted by the U.S. Geological Survey and Idaho State University, in cooperation with the U.S. Department of Energy. Batch experimental techniques were used to determine strontium linear sorption isotherms and distribution coefficients (K(d)'s) using simulated wastewater solutions prepared at pH 8.0??0.1 with variable concentrations of calcium and magnesium. Strontium linear sorption isotherm K(d)'s ranged from 12??1 to 85??3 ml/g, increasing as the concentration of calcium and magnesium decreased. The concentration of sorbed strontium and the percentage of strontium retained by the sediment were correlated to aqueous concentrations of strontium, calcium, and magnesium. The effect of these cation concentrations on strontium sorption was quantified using multivariate least-squares regression techniques. Analysis of data from these experiments indicates that increased concentrations of calcium and magnesium in wastewater discharged to waste disposal ponds at the INEL increases the availability of strontium for transport beneath the ponds by decreasing strontium sorption to the surficial sediment.

  1. Sorption of PAHs and PCBs to activated carbon: coal versus biomass-based quality.

    Science.gov (United States)

    Amstaetter, Katja; Eek, Espen; Cornelissen, Gerard

    2012-04-01

    The addition of activated carbon (AC) is an increasingly popular method for pollutant immobilization, and the AC material can be made of biomass or coal/fossil feedstock. The aim of the present study was to investigate whether there are differences between pollutant sorption to biomass and coal-based AC in the presence and absence of sediment. Through N(2) and CO(2) adsorption to probe surface area and pore size it was shown that the biomass-based AC had a stronger dominance of narrow pores in the size range 3.5-15Šthan the anthracite-based material. In the absence of sediment, sorption isotherms for the probe compounds pyrene and PCB-101 showed stronger sorption for the biomass-based AC (logarithmic Freundlich coefficients 8.15 for pyrene; 9.91 for PCB-101) than for the anthracite-based one (logarithmic Freundlich coefficients 7.20 and 9.70, respectively). In the presence of sediment, the opposite trend was observed, with the stronger sorption for anthracite-based AC. Thus, the presence of competing and/or pore-blocking sediment constituents reduces sorption to a larger extent for biomass-derived AC (factor of 5 for pyrene to almost 100 for PCB-101) than for anthracite-based AC (no reduction for pyrene to factor of 5 for PCB-101). This difference is tentatively attributed to the difference in pore size distribution, narrow pores being more prone to clogging, and could have implications for remediation feasibility with AC from different sources. Copyright © 2012 Elsevier Ltd. All rights reserved.

  2. Diffusion and sorption of neptunium(V) in compacted montmorillonite: effects of carbonate and salinity

    International Nuclear Information System (INIS)

    Tachi, Y.; Yotsuji, K.; Suyama, T.; Seida, Y.; Yui, M.; Nakazawa, T.; Yamada, N.; Ochs, M.

    2010-01-01

    Diffusion and sorption of radionuclides in compacted bentonite/montmorillonite are key processes in the safe geological disposal of radioactive waste. In this study, the effects of carbonate and salinity on neptunium(V) diffusion and sorption in compacted sodium montmorillonite were investigated by experimental and modeling approaches. Effective diffusion coefficients (D e ) and distribution coefficients (K d ) of 237 Np(V) in sodium montmorillonite compacted to a dry density of 800 kg m -3 were measured under four chemical conditions with different salinities (0.05/0.5 M NaCl) and carbonate concentrations (0.0.01 M NaHCO 3 ). D e values for carbonate-free conditions were of the order of 10 -10 -10 -11 m 2 s -1 and decreased as salinity increased, and those for carbonate conditions were of the order of 10 -11 -10 -12 m 2 s -1 and showed the opposite dependence. Diffusion-derived K d values for carbonate-free conditions were higher by one order of magnitude than those for carbonate conditions. Diffusion and sorption behaviors were interpreted based on mechanistic models by coupling thermodynamic aqueous speciation, thermodynamic sorption model (TSM) based on ion exchange, and surface complexation reactions, and a diffusion model based on electrical double layer (EDL) theory in homogeneous narrow pores. The model predicted the experimentally observed tendency of D e and K d qualitatively, as a result of the following mechanisms; 1) the dominant aqueous species are NpO 2 + and NpO 2 CO 3 - for carbonate-free and carbonate conditions, respectively, 2) the effects of cation excess and anion exclusion result in opposite tendencies of D e for salinity, 3) higher carbonate in solution inhibits sorption due to the formation of carbonate complexes. (orig.)

  3. Sorption of strontium and fractal scaling of the heterogeneous media in a candidate VLLW disposal site

    International Nuclear Information System (INIS)

    Jinsheng Wang; Rui Zuo; Yanguo Teng; Zongjian Sun; Qinhong Hu

    2010-01-01

    Because of the deposit and accumulation from the debris flow, the heterogeneous geological characteristics is obvious for a candidate very low level waste (VLLW) disposal site, with the grain size ranging from tens of microns to 75 cm. Therefore, it is challenging to directly measure the sorption capacity of the media and the distribution coefficient of some radionuclides, such as strontium. We have studies the correlation of the particle mass content with different grade size and the sorption capacity, which is important in the modeling of radionuclide migration in the heterogeneous disposal site. A total of three deep pits and five shallow trenches were excavated, and 21 solid samples were collected for laboratory experiments. The grade and percentage of the different-sized particles were obtained, and the fractal dimension (D) of the media was calculated from the results of sieved experiments. Steady state sorption time and sorption isotherm of strontium was determined in the heterogeneous media, and sorption and distribution of strontium in the heterogeneous media were evaluated by the relationship between the mass percentage and distribution coefficient (K d ) of the fine-particle media, which was comprised of selected particles with a diameter less than 1 mm, and the correlation on the K d and D was regressed fit. The results indicated that fractal dimension bounded from 2.39 to 2.62 in the media, and K d values of strontium ranged between 119 and 126 in the fine-particle media, and corresponding value was 11 and 43 in the original media. The correlation between K d and D was approximately linear. (author)

  4. Sorption of Pu onto some kinds of clay

    International Nuclear Information System (INIS)

    Jia Haihong; Si Gaohua; Liu Wei; Yu Jing

    2010-01-01

    There are rich clay mines holding in one area, so it's necessary to know about these clays' sorption capacity to Pu, for building radioactive waste repository in the area. Distribution coefficients of Pu onto different clays were acquired in static method, with the result about 104. The size of clay is different, but the result of Kds is near. In addition, it's estimated how far Pu moves in the most rapid speed in the clay based on these Kids', disregarding the influence of Pu-colloid. In a word, as a kind of backfilling material clays in the area can effectively prevent Pu from moving to environment, and when designing the backfilling layer, it's not necessary to catch clays through NO.200 sieve, if only considering the influence of Kd. (authors)

  5. Sorption kinetics of cesium on hydrous titanium dioxide

    International Nuclear Information System (INIS)

    Altas, Y.; Tel, H.; Yaprak, G.

    2003-01-01

    Two types of hydrous titanium dioxide possessing different surface properties were prepared and characterized to study the sorption kinetics of cesium. The effect of pH on the adsorption capacity were determined in both type sorbents and the maximum adsorption percentage of cesium were observed at pH 12. To elucidate the kinetics of ion-exchange reaction on hydrous titanium dioxide, the isotopic exchange rates of cesium ions between hydrous titanium dioxides and aqueous solutions were measured radiochemically and compared with each other. The diffusion coefficients of Cs + ion for Type1 and Type2 titanium dioxides at pH 12 were calculated as 2.79 x 10 -11 m 2 s -1 and 1.52 x 10 -11 m 2 s -1 , respectively, under particle diffusion controlled conditions. (orig.)

  6. Radionuclide sorption from the safety evaluation perspective

    International Nuclear Information System (INIS)

    1992-01-01

    Research and development directed towards the assessment of the long-term performance of radioactive waste disposal systems has been recognised as a priority area with a strong need for international co-operation and co-ordination. The ultimate aims is to promote the quality and credibility of safety assessment techniques for radioactive waste disposal. Sorption in the geosphere is one of the key processes for retarding the transport of radionuclide from the underground disposal facility to the biosphere. In many cases, sorption in the near field and in the biosphere is also important. A workshop, organised to favor discussion around a small number of invited papers, was held in October 1991: - to evaluate critically the way sorption processes are incorporated in performance assessment models; - to identify open issues of high priority, and; - to propose future activities to resolve these issues. These proceedings reproduce the invited papers and the conclusions and recommendations adopted by the workshop. Eight papers are in the INIS SCOPE. The main subjects studied are: sorption database comparison, sorption database development and three case studies, experimental techniques, adsorption models

  7. Sorption of radionuclides by tertiary clays

    International Nuclear Information System (INIS)

    Wagner, J.F.; Czurda, K.A.

    1990-01-01

    The sorption capacity of different clay types for some metals (Co, Cs, Sr and Zn), occurring as common radionuclides in radioactive waste deposits, had been analysed by a static (batch technique) and a dynamic method (percolation tests, in which the driving force is a hydraulic gradient). Sorption capacity generally increased with an increasing pH of solution. A decrease of sorption capacity had been observed in the order Zn > Cs ≥ Co > Sr for the batch and Cs > Zn > Sr > Co for the percolation tests. Clay marls showed a distinctly higher sorption respectively retention capacity as pure clays. Sorption capacity depends on solution parameters like type and concentration of radionuclide, pH, salt concentration, etc., and on rock parameters like mineral content (e.g. swelling clay minerals and carbonates), organic material, rock pH, micro fabric, etc. A third parameter of great influence is the contact time between clay and solution. The adsorption isotherms reflect two different adsorption mechanisms: a very rapid adsorption (a few minutes) on the external surfaces of clay minerals and a slow adsorption process (weeks and longer), due to the diffusion of metal ions into the interlayer space of clay minerals. 12 refs., 9 figs., 1 tab

  8. Arsenic sorption to nanoparticulate mackinawite (FeS): An examination of phosphate competition.

    Science.gov (United States)

    Niazi, Nabeel Khan; Burton, Edward D

    2016-11-01

    Nanoparticulate mackinawite (FeS) can be an important host-phase for arsenic (As) in sulfidic, subsurface environments. Although not previously investigated, phosphate (PO 4 3- ) may compete with As for available sorption sites on FeS, thereby enhancing As mobility in FeS-bearing soils, sediments and groundwater systems. In this study, we examine the effect of PO 4 3- on sorption of arsenate (As(V)) and arsenite (As(III)) to nanoparticulate FeS at pH 6, 7 and 9. Results show that PO 4 3- (at 0.01-1.0 mM P) did not significantly affect sorption of either As(V) or As(III) to nanoparticulate FeS at initial aqueous As concentrations ranging from 0.01 to 1.0 mM. At pH 9 and 7, sorption of both As(III) and As(V) to nanoparticulate FeS was similar, with distribution coefficient (K d ) values spanning 0.76-15 L g -1 (which corresponds to removal of 87-98% of initial aqueous As(III) and As(V) concentrations). Conversely, at pH 6, the sorption of As(III) was characterized by substantially higher K d values (6.3-93.4 L g -1 ) than those for As(V) (K d  = 0.21-0.96 L g -1 ). Arsenic K-edge X-ray absorption near edge structure (XANES) spectroscopy indicated that up to 52% of the added As(V) was reduced to As(III) in As(V) sorption experiments, as well as the formation of minor amounts of an As 2 S 3 -like species. In As(III) sorption experiments, XANES spectroscopy also demonstrated the formation of an As 2 S 3 -like species and the partial oxidation of As(III) to As(V) (despite the strictly O 2 -free experimental conditions). Overall, the XANES data indicate that As sorption to nanoparticulate FeS involves several redox transformations and various sorbed species, which display a complex dependency on pH and As loading but that are not influenced by the co-occurrence of PO 4 3- . This study shows that nanoparticulate FeS can help to immobilize As(III) and As(V) in sulfidic subsurface environments where As co-exists with PO 4 3- . Copyright © 2016 Elsevier Ltd. All

  9. Evaluation of Compressive Strength and Sorption/Solubility of Four Luting Cements

    Directory of Open Access Journals (Sweden)

    Tavangar MS

    2017-06-01

    Full Text Available Abstract: Statement of Problem: Compressive strength (CS and sorption/solubility of the luting cements are two associated factors. Searching a correlation between sorption/solubility and compressive strength of various luting cements is required. Objectives: To measure the water sorption/solubility, and compressive strength of three resin-based and one conventional glass ionomer (CGI luting cement after 1 and 24 h of immersion in distilled water and to determine if there is any correlation between those properties found. Materials and Methods: Four luting cements were investigated. For each material, 10 disc shaped specimens were prepared for measuring the sorption/solubility. The specimens were cured according to the manufacturer’s instructions, and the sorption/solubility were measured in accordance with the ISO 4049’s. For testing the compression strength, for each material 16 cylindrical specimens were prepared by insertion of cements into a stainless steel split mould. The specimens were cured, divided into groups of 8, and then stored in distilled water at (37 ± 1°C for 1 and 24 h. The test was performed using the universal testing machine, the maximum load was recorded and CS was calculated. The data were analysed using SPSS software version 18. One-way ANOVA, post-hoc Tukey’s test and Pearson’s correlation coefficient were performed. Results: G-CEM had the highest mean CS (153.60± 25.15 and CGI luting had the lowest CS (21.36±5.37 (p 0.05. The lowest mean sorption/solubility value was for RelyXTM U200 and Panavia F, and the highest for CGI luting (all p < 0.001. Conclusions: The compressive strength of all cements did not necessarily increase after 24 h and varied depending on the materials. There was a strong reverse correlation between sorption and CS values after both 1 and 24 h immersion. It may be practical for clinician to use those cements with the less sorption / solubility and more stable compression strength over

  10. Factors affecting the sorption of cesium in a nutrient-poor boreal bog

    International Nuclear Information System (INIS)

    Lusa, M.; Bomberg, M.; Virtanen, S.; Lempinen, J.; Aromaa, H.; Knuutinen, J.; Lehto, J.

    2015-01-01

    135 Cs is among the most important radionuclides in the long-term safety assessments of spent nuclear fuel, due to its long half-life of 2.3 My and large inventory in spent nuclear fuel. Batch sorption experiments were conducted to evaluate the sorption behavior of radiocesium ( 134 Cs) in the surface moss, peat, gyttja, and clay layers of 7-m-deep profiles taken from a nutrient-poor boreal bog. The batch distribution coefficient (K d ) values of radiocesium increased as a function of sampling depth. The highest K d values, with a geometric mean of 3200 L/kg dry weight (DW), were observed in the bottom clay layer and the lowest in the 0.5–1.0 m peat layer (50 L/kg DW). The maximum sorption in all studied layers was observed at a pH between 7 and 9.5. The in situ K d values of 133 Cs in surface Sphagnum moss, peat and gyttja samples were one order of magnitude higher than the K d values obtained using the batch method. The highest in situ K d values (9040 L/kg DW) were recorded for the surface moss layer. The sterilization of fresh surface moss, peat, gyttja and clay samples decreased the sorption of radiocesium by 38%, although the difference was not statistically significant. However, bacteria belonging to the genera Pseudomonas, Paenibacillus, Rhodococcus and Burkholderia isolated from the bog were found to remove radiocesium from the solution under laboratory conditions. The highest biosorption was observed for Paenibacillus sp. V0-1-LW and Pseudomonas sp. PS-0-L isolates. When isolated bacteria were added to sterilized bog samples, the removal of radiocesium from the solution increased by an average of 50% compared to the removal recorded for pure sterilized peat. Our results demonstrate that the sorption of radiocesium in the bog environment is dependent on pH and the type of the bog layer and that common environmental bacteria prevailing in the bog can remove cesium from the solution phase. - Highlights: • pH and the type of the bog layer affect

  11. Immobilization of inorganic ion-exchanger into bio-polymer foams - Application to cesium sorption

    International Nuclear Information System (INIS)

    Vincent, Chloe; Hertz, Audrey; Barre, Yves; Vincent, Thierry; Guibal, Eric

    2014-01-01

    Nickel-potassium ferrocyanide (along with other ferrocyanide sub-products, as shown by mineralization, SEM-EDX and XRD analyses) has been immobilized in highly porous discs of chitin for the sorption of Cs(I) from near neutral solutions. The immobilization process allows synthesizing stable materials that can bind up to 80 mg Cs g -1 (i.e., 240 mg Cs g -1 ion-exchanger). Cesium sorption is hardly affected by the pH between pH 2 and 8. The sorbent is selective to Cs(I) even in the presence of high concentrations of Na(I), K(I), Rb(I) or NH 4+ . The pseudo-second order rate equation fits well kinetic profiles: the rate coefficient increases with the flow rate of recirculation (to force the access to potentially non-interconnected pores), as an evidence of the control of uptake kinetics by diffusion properties. In fixed-bed columns, the breakthrough curve is accurately described by the Clark model and the sorption capacity (at sorbent saturation) is consistent with the values obtained in sorption isotherms. Preliminary tests performed on 137 Cs spiked solutions confirm the efficiency of the material for the treatment of effluents bearing radionuclides. (authors)

  12. Sorption and desorption behaviors of diuron in soils amended with charcoal.

    Science.gov (United States)

    Yu, Xiang-Yang; Ying, Guang-Guo; Kookana, Rai S

    2006-11-01

    Charcoal derived from the partial combustion of vegetation is ubiquitous in soils and sediments and can potentially sequester organic contaminants. To examine the role of charcoal in the sorption and desorption behaviors of diuron pesticide in soil, synthetic charcoals were produced through carbonization of red gum (Eucalyptus spp.) wood chips at 450 and 850 degrees C (referred to as charcoals BC450 and BC850, respectively, in this paper). Pore size distribution analyses revealed that BC850 contained mainly micropores (pores approximately 0.49 nm mean width), whereas BC450 was essentially not a microporous material. Short-term equilibration (diuron in a soil amended with various amounts of charcoals of both types. The sorption coefficients, isotherm nonlinearity, and apparent sorption-desorption hysteresis markedly increased with increasing content of charcoal in the soil, more prominently in the case of BC850, presumably due to the presence of micropores and its relatively higher specific surface area. The degree of apparent sorption-desorption hystersis (hysteresis index) showed a good correlation with the micropore volume of the charcoal-amended soils. This study indicates that the presence of small amounts of charcoal produced at high temperatures (e.g., interior of wood logs during a fire) in soil can have a marked effect on the release behavior of organic compounds. Mechanisms of this apparent hysteretic behavior need to be further investigated.

  13. An assessment of strontium sorption onto bentonite buffer material in waste repository.

    Science.gov (United States)

    Pathak, Pankaj

    2017-03-01

    In the present study, changes occurring in sorption characteristics of a representative bentonite (WIn-BT) exposed to SrCl 2 (0.001-0.1 M) under the pH range of 1-13 were investigated. Such interaction revealed a significant variation in surface charge density and binding energy of ions with respect to bentonite, and alteration in their physicochemical properties viz., specific surface area, cation exchange capacity, thermal and mechanical behaviour were observed. The distribution coefficients (k d ) calculated for sorption onto virgin (UCBT) and contaminated bentonite (CBT) indicated a greater influence of mineralogical changes occurred with variance of pH and strontium concentration. Notably, the sorption mechanism clearly elucidates the effect of structural negative charge and existence of anionic metal species onto CBT, and depicted the reason behind significant k d values at highly acidic and alkaline pH. The maximum k d of UCBT and CBT (0.001M SrCl2) were 8.99 and 2.92 L/kg, respectively, at the soil pH 8.5; whereas it was 2.37 and 1.23 L/kg at pH 1 for the CBT (0.1M SrCl2) and CBT (0.01M SrCl2) , respectively. The findings of this study can be useful to identify the physicochemical parameters of candidate buffer material and sorption reversibility in waste repository.

  14. Effects of pig slurry on the sorption of sulfonamide antibiotics in soil.

    Science.gov (United States)

    Thiele-Bruhn, S; Aust, M O

    2004-07-01

    Sorption of p-aminobenzoic acid (pABA) and five sulfonamide antibiotics to loess Chernozem topsoil amended with varied additions of pig slurry was investigated in batch trials. In unfertilized soil, partition coefficients (Kd) of sulfonamides ranged from 0.3 to 2.0. Strong sorption nonlinearity (1/n = 0.5 to 0.8) was best fitted by the Freundlich isotherm (R2 = 0.7 to 1.0) and was indicative for specific sorption mechanisms. Adsorption to pig slurry was much stronger, and nondesorbable portions were increased compared with soil. However, in a mixture of soil and slurry (50:1 w/w), sorption of the antibiotics was significantly decreased at a lower concentration range of pABA and the sulfonamides. This was attributed to competitive adsorption of dissolved organic matter (DOM) constituents from manure. An increase in pig slurry amendment resulted in increased total organic matter, DOM concentration, and ionic strength, but pH decreased. As a result, the nonadsorbed portions of pABA, sulfanilamide, and sulfadiazine (logD(ow) 0.1)--remained nearly constant in the presence of increased manure input. The pH changes caused by manure amendment strongly affected ionisation status of the latter compounds, thus resulting in increased adsorption, which compensated the mobilizing effect of DOM. It is suggested that the effect of manure be considered in test methods to determine the soil retention of pharmaceutical substances.

  15. Sorption of 4-ethylphenol and 4-ethylguaiacol by suberin from cork.

    Science.gov (United States)

    Gallardo-Chacón, Joan-Josep; Karbowiak, Thomas

    2015-08-15

    Cork shows an active role in the sorption of volatile phenols from wine. The sorption properties of 4-ethylphenol and 4-ethylguaiacol phenols in hydro-alcoholic medium placed in contact with suberin extracted from cork were especially investigated. To that purpose, suberin was immersed in model wine solutions containing several concentrations of each phenol and the amount of the compound remaining in the liquid phase was determined by SPME-GC-MS. Sorption isotherms of 4-ethylguaiacol and 4-ethylphenol by suberin followed the Henry's model. The solid/liquid partition coefficients (KSL) between the suberin and the model wine were also determined for several other volatile phenols. Suberin displayed rather high sorption capacity, which was positively correlated to the hydrophobicity of the volatile. Finally, the capacity of suberin to decrease the concentration of 4-ethylphenol and 4-ethylguaiacol was also tested in real wines affected by a Brettanomyces character. It also lead to a significant reduction of their concentration in wine. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. Atrazine sorption by hydroxy-interlayered clays and their organic complexes.

    Science.gov (United States)

    Indraratne, Srimathie P; Farenhorst, Annemieke; Goh, Tee Boon

    2008-01-01

    This study examined the sorption of atrazine by hydroxy-Fe interlayered montmorillonite (FeMt) and its hydroquinone (FeMtHQ), citrate (FeMtCt) and catechol (FeMtCC) complexes as well as by hydroxy-Al interlayered montmorillonite (AlMt) and its hydroquinone (AlMtHQ) and citrate (AlMtCt) complexes. Found among the clays were sorption distribution coefficients (K(d)) ranging from 24 to 123 mL g(-1) and maximum sorption (M) ranging from 2.2 to 16.8 microg g(-1). Both K(d) and M decreased in the order of FeMtCC > FeMtHQ > AlMtHQ > (AlMt = FeMt) > (AlMtCt = FeMtCt). The pH was negatively correlated with both K(d) (r = -0.90, p 0.96, p 0.94, p AlMt). This suggests that functional groups of Fe-OH and Al-OH in FeMt and AlMt reduced the available sorption sites for atrazine by making complexes with citrate ions while forming FeMtCt and AlMtCt. The atrazine was sorbed through the hydrophobic interactions with organic compound surfaces as well as through H-bonding and ionic bonding with clay-mineral surfaces.

  17. Sorption of Europium in zirconium silicate

    International Nuclear Information System (INIS)

    Garcia R, G.

    2004-01-01

    Some minerals have the property of sipping radioactive metals in solution, that it takes advantage to manufacture contention barriers that are placed in the repositories of nuclear wastes. The more recent investigations are focused in the development of new technologies guided to the sorption of alpha emissors on minerals which avoid their dispersion in the environment. In an effort to contribute to the understanding of this type of properties, some studies of sorption of Europium III are presented like homologous of the americium, on the surface of zirconium silicate (ZrSiO 4 ). In this work the results of sorption experiences are presented as well as the interpretation of the phenomena of the formation of species in the surface of the zirconium silicate. (Author)

  18. Sorption of radioactive technetium on pyrrhotine

    International Nuclear Information System (INIS)

    Shen, D.; Fan, X.H.; Su, X.G.; Zeng, J.S.; Dong, Y.

    2002-01-01

    The sorption behavior of technetium on pyrrhotine was studied with batch experiments and diluted sulfuric acid (less than 2.88 mol/l) was used to dissolve the technetium adsorbed on pyrrhotine. A significant sorption of technetium on pyrrhotine was observed under aerobic and anaerobic conditions, and the sorption on the mineral was supposed to be due to the reduction of TcO 4 - to insoluble TcO 2 x nH 2 O. Sorbed technetium on the mineral could be desorbed by diluted sulfuric acid. The maximum desorption ratio under aerobic conditions was much higher than that of under anaerobic conditions, meanwhile, the desorption rates under anaerobic conditions were higher than that of under aerobic conditions in the initial stage of the experiments. (author)

  19. Water sorption and transport in dry crispy bread crust

    NARCIS (Netherlands)

    Meinders, M.B.J.; Nieuwenhuijzen, van N.H.; Tromp, R.H.; Hamer, R.J.; Vliet, van T.

    2010-01-01

    Water sorption and dynamical properties of bread crust have been studied using gravimetric sorption experiments. Water uptake and loss were followed while relative humidity (RH) was stepwise in- or decreased (isotherm experiment) or varied between two adjusted values (oscillatory experiment).

  20. The sorption of acids in cellular side of apple pressing

    International Nuclear Information System (INIS)

    Asoev, M.G.; Mukhiddinov, Z.K.

    1994-01-01

    Equilibrium swell of sample refuse after separation of water is use for study of sorption of hydrochloric acid. Quantity adsorb acids set a price to difference her concentration before and after equilibrium sorption

  1. A kinetic approach to model sorption dynamics of radionuclides in soils: from desire to operational application?

    Energy Technology Data Exchange (ETDEWEB)

    Martin-Garin, A.; Garcia-Sanchez, L.; Coppin, F. [Institut de Radioprotection et de Surete Nucleaire (France); Krimissa, M. [Electricite de France (France)

    2014-07-01

    The understanding of radionuclides (RN) behaviour and subsequent fluxes in the soil/solution/plant system is still a challenging question for realistic short, medium or long term risk assessments. Several years of researches have been devoted to improve the modeling of radionuclides migration in soils and their transfer to other compartments of the biosphere (eg. plants), as well as to constitute databases of model parameters (eg. distribution coefficient (K{sub d})). These works contributed to define, and then to extend, the domain of applicability of radioecological models, but they also helped to identify gaps and ways to improve them. However, these improvements have not been fully taken into account. Within this framework, the evolution of RN chemical speciation in time (often described as aging) was specifically addressed, as it control RN retention properties and bioavailability. Regarding soluble and RN solid speciation in soils, such processes generally lead to a shift from low to high K{sub d} values. Common explanations consist in the transfer of sorbed RN to non-(or less) exchangeable solid species, or in the lixiviation of the most available radionuclide fraction, both decreasing the reversibly sorbed RN fraction. Kinetics studies have examined such changes in K{sub d} value with time and various models have been proposed to fit the different evolutions. Among them, an empirical three-box model is often used to describe the kinetics of RN sorption when RN mostly occurs in the soil solution as a free ion (eg. Cs and Sr). This model assumes that the radionuclide may be sorbed either as a labile fraction, defining an exchangeable K{sub d}-like liquid/solid distribution, or sorbed as a less or non-exchangeable fraction. The last is estimated through its corresponding sorption and desorption rate constants, which describes a pseudo-first order reaction. Modeling of sorption dynamic is a way to link K{sub d} values derived from field-contaminated soils to

  2. Tritium sorption on protective coatings for concrete

    International Nuclear Information System (INIS)

    Miller, J.M.; Senohrabek, J.A.; Allsop, P.A.

    1992-11-01

    Because of the high sorption level of tritium on unprotected concrete, a program to examine the effectiveness of various concrete coatings and sealants in reducing tritium sorption was undertaken, and various exposure conditions were examined. Coatings of epoxy, polyurethane, bituminous sealant, bituminous sealant covered with polyvinylidene chloride wrap, alkyd paint, and sodium silicate were investigated with tritium (HTO) vapor concentration, humidity and contact time being varied. An exposure to HT was also carried out, and the effect of humidity on the tritium desorption rate was investigated. The relative effectiveness of the coatings was in the order of bituminous sealant + wrap > bituminous sealant > solvent-based epoxy > 100%-solids epoxy > alkyd paint > sodium silicate. The commercially available coatings for concrete resulted in tritium sorption being reduced to less than 7% of unprotected concrete. This was improved to ∼0.1% with the use of the Saran wrap (polyvinylidene chloride). The amount of tritium sorbed was proportional to tritium concentration. The total tritium sorbed decreased with an increase in humidity. A saturation effect was observed with increasing exposure time for both the coated and unprotected samples. Under the test conditions, complete saturation was not achieved within the maximum 8-hour contact time, except for the solvent-based epoxy. The desorption rate increased with a higher-humidity air purge stream. HT desorbed more rapidly than HTO, but the amount sorbed was smaller. The experimental program showed that HTO sorption by concrete can be significantly reduced with the proper choice of coating. However, tritium sorption on concrete and proposed coatings will continue to be a concern until the effects of the various conditions that affect the adsorption and desorption of tritium are firmly established for both chronic and acute tritium release conditions. Material sorption characteristics must also be considered in

  3. On the derivation of a sorption database

    International Nuclear Information System (INIS)

    Ewart, F.T.; Haworth, A.; Wisbey, S.J.

    1992-01-01

    The safety arguments in support of many radioactive waste repository concepts are heavily dependent on the existence of a sorption reaction. Such a reaction will, in the near field, reduce the magnitude of the release of a number of hazardous radionuclides so that their release to the geosphere is dispersed in time. In the geosphere, the sorption reactions provide a mechanism whereby the migration of the elements released from the repository is retarded and the radioisotopes then subsequently decay. The processes involved in sorption cannot in many cases be satisfactorily represented in thermodynamic terms such as are employed in the description of dissolution and precipitation. Experiments that investigate these reactions are not easy to perform. The sorption parameters that are obtained experimentally for the near field relate, in the UK case, to sorption on to a cementitious surface. These surfaces, since they consist substantially of calcium hydroxide or calcium silicate hydrates, control the aqueous chemistry, do not permit pH changes to be made and limit the range of concentrations of sorbate that may be used. In the far field, on the other hand, the surfaces are not in general so active with respect to the solution chemistry and data can be obtained across a wide spectrum of aqueous chemistries. These data, although they may be useful in testing and parameterizing models, may not have validity under field conditions since the minerals will, inevitably, react to the changes in water chemistry, over geological timescales. The uncertainties in the experimental data are, for many elements and solids, balanced by a reasonable agreement between workers in the values of the parameters used to describe sorption. 22 refs., 1 fig., 1 tab

  4. Characterization of soil organic matter by FT-IR spectroscopy and its relationship with chlorpyrifos sorption.

    Science.gov (United States)

    Parolo, María Eugenia; Savini, Mónica Claudia; Loewy, Ruth Miriam

    2017-07-01

    Sorption of non-ionic organic compounds to soil is usually expressed as the carbon-normalized partition coefficient (K OC ) assuming that the main factor that influences the amount sorbed is the organic carbon content (OC) of the soil. However, K OC can vary across a range of soils. The influence of certain soil characteristics on the chlorpyrifos K OC values variation for 12 representative soils of the Northpatagonian Argentinian region with different physicochemical properties was investigated for this study. The chlorpyrifos sorption coefficients normalized by the OC content were experimentally obtained using the batch equilibrium method; the K OC values ranged between 9000-20,000 L kg -1 . The soil characteristics assessed were pH, clay content and spectral data indicative of soil organic matter (SOM) quality measured by FT-IR on the whole soil. The bands considered in the spectroscopic analyses were those corresponding to the aliphatic components, 2947-2858 cm -1 (band A) and the hydrophilic components, 1647-1633 cm -1 (band B). A significant relationship was found (R 2  = 0.66) between chlorpyrifos sorption (K OC ) and the variables pH and A/B height band ratio. The correlation between the values predicted by the derived model and the experimental data was significant (r = 0.89 p chlorpyrifos sorption coefficient through the use of a simple, rapid, and environmentally-friendly measurement. K OC analysis in relation to soil properties represents a valuable contribution to the understanding of the attenuation phenomena of the organic contaminants off-site migration in the environment. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Long Term Sorption Diffusion Experiment (LTDE-SD). Performance of main in situ experiment and results from water phase measurements

    International Nuclear Information System (INIS)

    Widestrand, Henrik; Byegaard, Johan; Nilsson, Kersti; Hoeglund, Susanne; Gustafsson, Erik; Kronberg, Magnus

    2010-12-01

    sorption to colloids in the aqueous phase was of minor importance. Furthermore, the measurements performed after a general colloid filtration showed no significant concentrations of inorganic colloids. The natural redox conditions were difficult to maintain during the experiment. Therefore the experiment was performed under the oxidizing conditions (E h ∼470 mV) that was obtained during the circulation of the groundwater. Sorption occurred on equipment during the experiment, in particular for some surface complexation sorbing tracers, possibly due to iron-oxy-hydroxides formed on equipment surfaces. Quantification was made of the amount of sorption on the equipment in order to enable corrections in the evaluation procedures. The sorption occurring for ion-exchange sorbing tracers was concluded to predominately be an effect of interaction with the geologic material since the sorbed amount on the equipment was found to be insignificant. Natural pressure conditions were maintained throughout the experiment time and consequently penetration into the rock matrix must be considered as a result only of diffusion since no advection could have been involved. Modelling in order to determine sorption coefficients (K a , K d ) was performed using a homogeneous porosity sorption-diffusion model using fixed data for porosity and matrix diffusivity from laboratory investigations on LTDE-SD core materials. For the ion-exchange sorbing tracers, the in situ evaluated K d was in the range of the batch sorption results or near the highest values (fracture material) from the batch sorption results. This indicates that a sorption-diffusion model can describe the concentration losses reasonably well for the ion-exchange sorbing tracers. However, due to the sorption on equipment, one should treat these results with care and consider the analysis of the sampled rock material before any definitive conclusions can be made based on the actual penetration profiles of the rock

  6. Long Term Sorption Diffusion Experiment (LTDE-SD). Performance of main in situ experiment and results from water phase measurements

    Energy Technology Data Exchange (ETDEWEB)

    Widestrand, Henrik; Byegaard, Johan; Nilsson, Kersti; Hoeglund, Susanne; Gustafsson, Erik (Geosigma AB, Uppsala (Sweden)); Kronberg, Magnus (Swedish Nuclear Fuel and Waste Management Co. (Sweden))

    2010-12-15

    radionuclide sorption to colloids in the aqueous phase was of minor importance. Furthermore, the measurements performed after a general colloid filtration showed no significant concentrations of inorganic colloids. The natural redox conditions were difficult to maintain during the experiment. Therefore the experiment was performed under the oxidizing conditions (E{sub h} approx470 mV) that was obtained during the circulation of the groundwater. Sorption occurred on equipment during the experiment, in particular for some surface complexation sorbing tracers, possibly due to iron-oxy-hydroxides formed on equipment surfaces. Quantification was made of the amount of sorption on the equipment in order to enable corrections in the evaluation procedures. The sorption occurring for ion-exchange sorbing tracers was concluded to predominately be an effect of interaction with the geologic material since the sorbed amount on the equipment was found to be insignificant. Natural pressure conditions were maintained throughout the experiment time and consequently penetration into the rock matrix must be considered as a result only of diffusion since no advection could have been involved. Modelling in order to determine sorption coefficients (K{sub a}, K{sub d}) was performed using a homogeneous porosity sorption-diffusion model using fixed data for porosity and matrix diffusivity from laboratory investigations on LTDE-SD core materials. For the ion-exchange sorbing tracers, the in situ evaluated K{sub d} was in the range of the batch sorption results or near the highest values (fracture material) from the batch sorption results. This indicates that a sorption-diffusion model can describe the concentration losses reasonably well for the ion-exchange sorbing tracers. However, due to the sorption on equipment, one should treat these results with care and consider the analysis of the sampled rock material before any definitive conclusions can be made based on the actual penetration profiles of

  7. Sorption Properties of Some Romanian Gingerbread

    Directory of Open Access Journals (Sweden)

    Tulbure Anca

    2014-06-01

    Full Text Available Water activity of gingerbread is very important for keeping the product freshness and shelf life. Water activity is influenced by composition, water content and temperature. The water content of gingerbread could vary according with storage condition. i.e. rH. 11 gingerbread samples were analysed. The water content and water activity lies between 7.0 and 12.6% and respectively 0.590 and 0.715. The sorption isotherms were determined at 30°C by gravimetric method. The moisture sorption is influenced by composition, especially sweeteners and humectants. Honey and invert sugar have the same impact on gingerbread higroscopicity.

  8. Sorption of radionuclides on hard rocks

    International Nuclear Information System (INIS)

    Berry, J.A.; Bourke, P.J.; Green, A.; Littleboy, A.K.

    1987-09-01

    Methods for measuring sorption on hard rocks, particularly of strontium, caesium, neptunium and americium on Darley Dale sandstone and Welsh slate have been investigated. The methods tried included batch tests with crushed rock and tests of simultaneous diffusion and convection with sorption on intact rock. High pressures (800m H 2 O) were used in the convective tests to pump water quickly through the rock samples and to measure high sorptivities in times shorter than those needed in the diffusive methods with intact samples. (author)

  9. A Sorption Hysteresis Model For Cellulosic Materials

    DEFF Research Database (Denmark)

    Frandsen, Henrik Lund; Damkilde, Lars

    2006-01-01

    The equilibrium concentration of adsorbed water in cellulosic materials is dependent on the history of the variations of vapor pressure in the ambient air, i.e. sorption hysteresis. Existing models to describe this phenomenon such as the independent domain theory have numerical drawbacks and....../or imply accounting for the entire history variations of every material point. This paper presents a sorption hysteresis model based on a state formulation and expressed in closed-form solutions, which makes it suitable for implementation into a numerical method....

  10. The sorption behaviour of 99Tc on activated carbon

    International Nuclear Information System (INIS)

    Xia Deying; Zeng Jishu

    2004-01-01

    The sorption behaviour of 99 Tc on apricot-pit activated carbon with batch experiment is studied. The influence of such factors as sorbent particle size, temperature, pH value on sorption ratio, and the Freundlich sorption isotherms are reported in this paper. (author)

  11. Suitability of Moshi Pumice for Phosphorus Sorption in Constructed ...

    African Journals Online (AJOL)

    The study of Moshi Pumice's phosphorus sorption behaviours and properties was carried out in laboratory scale where by 1-2 mm, 2-4 mm and 4-8 mm grains were tested using batch experiments. The results show that Moshi Pumice has high phosphorus sorption capacity. The sorption capacity for the Moshi Pumice was ...

  12. Phosphorus sorption in relation to soil grain size and geochemical ...

    African Journals Online (AJOL)

    By using stepwise regression, the combination of Al, Fe, clay and Ca predicted more than 94% of the variation in the P sorption capacity of soils samples from Simiyu and Kagera basins. These four soil properties, which are strongly related to P sorption, could therefore be used as quick tests for predicting the P sorption ...

  13. Attenuation of polychlorinated biphenyl sorption to charcoal by humic acids

    NARCIS (Netherlands)

    Koelmans, A.A.; Meulman, B.; Meijer, T.; Jonker, M.T.O.

    2009-01-01

    Strong sorption to black carbon may limit the environmental risks of organic pollutants, but interactions with cosorbing humic acid (HA) may interfere. We studied the attenuative effect of HA additions on the sorption of polychlorinated biphenyls (PCBs) to a charcoal. "Intrinsic" sorption to

  14. Sorption mechanisms of perfluorinated compounds on carbon nanotubes

    International Nuclear Information System (INIS)

    Deng Shubo; Zhang Qiaoying; Nie Yao; Wei Haoran; Wang Bin; Huang Jun; Yu Gang; Xing Baoshan

    2012-01-01

    Sorption of perfluorinated compounds (PFCs) on carbon nanotubes (CNTs) is critical for understanding their subsequent transport and fate in aqueous environments, but the sorption mechanisms remain largely unknown. In this study, the sorption of six PFCs on CNTs increased with increasing C-F chain length when they had a same functional group, and the CNTs with hydroxyl and carboxyl groups had much lower adsorbed amount than the pristine CNTs, indicating that hydrophobic interaction dominated the sorption of PFCs on the CNTs. Electrostatic repulsion suppressed the sorption of PFCs on the CNTs, resulting in the lower sorption with increasing pH. Hydrogen bonding interaction was negligible. The hydrophobic C-F chains can be closely adsorbed on the CNTs surface in parallel to the axis or along the curvature, making it impossible to form micelles on the CNT surface, leading to the lower sorption than other adsorbents. Highlights: ► Sorption capacities of PFOA on different CNTs are less than that on activated carbon and resins. ► Hydrophobic interaction is principally involved in the sorption of PFCs on CNTs. ► Electrostatic repulsion suppresses the sorption of PFCs on CNTs. - Hydrophobic interaction dominated the sorption of perfluorinated compounds on carbon nanotubes, while electrostatic repulsion suppressed their sorption.

  15. Modelling Ni diffusion in bentonite using different sorption models

    International Nuclear Information System (INIS)

    Pfingsten, W.; Baeyens, B.; Bradbury, M.

    2010-01-01

    different modelling approaches a) an analytical solution with constant Kd using a constant Ni(II) concentration level at x = 0 (e.g. at the canister surface) and zero Ni(II) initial background concentration in the bentonite, b) a numerical 'constant K d approach' taking into account the initial Ni(II) background concentration in the bentonite pore water, and c) a reactive transport approach using the code MCOTAC in one-dimensional spatial geometry with an incorporated mechanistic sorption model which includes surface proto-lysis, surface complexation and cation exchange reactions. Charge balance is explicitly formulated for the surface complexation reactions. Selectivity coefficients and surface complexation data for Ni(II) were taken from Bradbury and Baeyens (2005); the related Fe(II) data were obtained from the Linear Free Energy Relationship (LFER) contained in the same publication. The Ni(II) breakthrough in the bentonite was calculated for different Ni(II) concentration levels with and without considering competition with Fe(II) on exchange and surface complexation sites for different Fe(II) concentrations in the bentonite pore water. The comparison allows the following observations to be made: for trace Ni(II) concentrations, the numerical 'constant K d approach' yield similar results to the reactive transport approach. For higher Ni(II) concentrations, the calculated Ni(II) breakthroughs differ from each other: the reactive transport approach yields an earlier breakthrough than the numerical 'constant K d approach' for a Ni concentration level of 10 -5 M. However, for a Ni(II) concentration level of 10 -4 M, the reactive transport approach yield a later but steeper breakthrough, reaching the maximum Ni(II) concentration level earlier than the numerical 'constant K d approach'. Fe(II) competition reactions could only be taken into account using the reactive transport approach. The results yield a general dependency of the Ni

  16. Hydration and sorption characteristics of a polyfunctional weak-base anion exchanger after the sorption of vanillin and ethylvanillin

    Science.gov (United States)

    Rodionova, D. O.; Voronyuk, I. V.; Eliseeva, T. V.

    2016-07-01

    Features of the sorption of substituted aromatic aldehydes by a weak-base anion exchanger under equilibrium conditions are investigated using vanillin and ethylvanillin as examples. Analysis of the sorption isotherms of carbonyl compounds at different temperatures allows us to calculate the equilibrium characteristics of their sorption and assess the entropy and enthalpy contributions to the energy of the process. Hydration characteristics of the macroporous weak-base anion exchanger before and after the sorption of aromatic aldehydes are compared.

  17. Re-evaluation of the sorption behaviour of Bromide and Sulfamethazine under field conditions using leaching data and modelling methods

    Science.gov (United States)

    Gassmann, Matthias; Olsson, Oliver; Höper, Heinrich; Hamscher, Gerd; Kümmerer, Klaus

    2016-04-01

    The simulation of reactive transport in the aquatic environment is hampered by the ambiguity of environmental fate process conceptualizations for a specific substance in the literature. Concepts are usually identified by experimental studies and inverse modelling under controlled lab conditions in order to reduce environmental uncertainties such as uncertain boundary conditions and input data. However, since environmental conditions affect substance behaviour, a re-evaluation might be necessary under environmental conditions which might, in turn, be affected by uncertainties. Using a combination of experimental data and simulations of the leaching behaviour of the veterinary antibiotic Sulfamethazine (SMZ; synonym: sulfadimidine) and the hydrological tracer Bromide (Br) in a field lysimeter, we re-evaluated the sorption concepts of both substances under uncertain field conditions. Sampling data of a field lysimeter experiment in which both substances were applied twice a year with manure and sampled at the bottom of two lysimeters during three subsequent years was used for model set-up and evaluation. The total amount of leached SMZ and Br were 22 μg and 129 mg, respectively. A reactive transport model was parameterized to the conditions of the two lysimeters filled with monoliths (depth 2 m, area 1 m²) of a sandy soil showing a low pH value under which Bromide is sorptive. We used different sorption concepts such as constant and organic-carbon dependent sorption coefficients and instantaneous and kinetic sorption equilibrium. Combining the sorption concepts resulted in four scenarios per substance with different equations for sorption equilibrium and sorption kinetics. The GLUE (Generalized Likelihood Uncertainty Estimation) method was applied to each scenario using parameter ranges found in experimental and modelling studies. The parameter spaces for each scenario were sampled using a Latin Hypercube method which was refined around local model efficiency maxima

  18. Sorption databases for the cementitious near-field of a L/ILW repository for performance assessment

    International Nuclear Information System (INIS)

    Bradbury, M.H.; Sarott, F.A.

    1995-03-01

    Approximately 95% of the material in the L/ILW repository for short-lived low- and intermediate-level wastes consists of concrete; the remaining approx. 5% consists of steel (4%) and high molecular weight organic waste components (1%). Radionuclide sorption onto concrete represents one of the most important retardation mechanisms in the disposal caverns. This report compiles the sorption properties of hydrated cement, the most important sorbing material present in concrete, in the form of data sets for safety relevant nuclides under repository conditions; these data can then be used directly in performance assessment. Processes which affect sorption onto cement in the disposal caverns are documented in different data sets in this report. In this report, the distribution coefficients for radionuclides on cement are based to a large extent on values measured under repository-relevant conditions; this is true for cement without complexants in particular. (author) figs., tabs., refs

  19. Sorption of 60Co on a synthetic titanosilicate analogue of the mineral penkvilksite-2O and antimonysilicate

    International Nuclear Information System (INIS)

    Koudsi, Y.; Dyer, A.

    2001-01-01

    The ability of two different types of synthetic inorganic ion-exchangers to sorb radioactive cobalt-60 using a batch-type method was studied. The two materials examined were the analogue of the natural titanosilicate penkvilksite-2O (AM-3) and a synthetic antimonysilicate. Ion-exchange experiments were performed with solutions labelled with radioactive cobalt ( 60 Co). The sorption of 60 Co onto the two samples materials were compared in terms of distribution coefficient (K d ), sorption percentage and cobalt quantity removed in mg per gram weight of the material. Several parameters were investigated viz. contact time, cobalt concentration, and sorbent concentration. It was found that the batch factor and cobalt concentration had a significant influence on the sorption of cobalt onto both of the materials. This was associated with the difference in pH generated by suspensions of the materials in water which was alkaline for the penkvilksite-2O analogue, and acid for the synthetic antimonysilicate. (author)

  20. Sorption behaviour of Np(IV) on illite, shale and MX-80 in high ionic strength solutions

    International Nuclear Information System (INIS)

    Shinya Nagasaki; Riddoch, Justin; Goguen, Jared; Walker, Andrew; Tammy Tianxiao Yang

    2017-01-01

    The dependence of sorption distribution coefficient (K_d) of Np(IV) for illite, shale and MX-80 was investigated as a function of pH_c and ionic strength (I) under high ionic strength, reducing conditions. The overall trends of K_d on three solids were independent of pH_c at 5 ≤ pH_c ≤ 10 and I at 0.5 M ≤ I ≤ 6 M. The surface complexation constants of Np(IV) sorption on illite and MX-80 were estimated by the 2 SPNE SC/CE model. The sorption model well predicted the pH_c dependence of K_d, but could not completely describe the ionic strength dependence. (author)

  1. A suggested approach toward measuring sorption and applying sorption data to repository performance assessment

    International Nuclear Information System (INIS)

    Rundberg, R.S.

    1991-01-01

    The sorption of radioisotopes in relation to geologic disposal of radioactive wastes is discussed. Properties of the radioactive materials, rocks, and minerals, and the chemistry involved are described. 51 refs., 12 figs. CBS

  2. Sorption of fission nuclides on model milk components. II. Sorption of radiostrontium on hydroxyapatite in milk and whey

    International Nuclear Information System (INIS)

    Rosskopfova, O.; Kopunec, R.; Matel, L.; Macasek, F.

    1999-01-01

    In this work the whey was chosen as a model solution of liquid phase for sorption study of strontium on hydroxyapatite. The whey was obtained using two methods - ultracentrifugation and precipitation of casein. The sorption was studied at a different pH and at a different concentration of calcium. The sorption of strontium on hydroxyapatite from milk was studied, too. (authors)

  3. Development of mechanistic sorption model and treatment of uncertainties for Ni sorption on montmorillonite/bentonite

    International Nuclear Information System (INIS)

    Ochs, Michael; Ganter, Charlotte; Tachi, Yukio; Suyama, Tadahiro; Yui, Mikazu

    2011-02-01

    Sorption and diffusion of radionuclides in buffer materials (bentonite) are the key processes in the safe geological disposal of radioactive waste, because migration of radionuclides in this barrier is expected to be diffusion-controlled and retarded by sorption processes. It is therefore necessary to understand the detailed/coupled processes of sorption and diffusion in compacted bentonite and develop mechanistic /predictive models, so that reliable parameters can be set under a variety of geochemical conditions relevant to performance assessment (PA). For this purpose, JAEA has developed the integrated sorption and diffusion (ISD) model/database in montmorillonite/bentonite systems. The main goal of the mechanistic model/database development is to provide a tool for a consistent explanation, prediction, and uncertainty assessment of K d as well as diffusion parameters needed for the quantification of radionuclide transport. The present report focuses on developing the thermodynamic sorption model (TSM) and on the quantification and handling of model uncertainties in applications, based on illustrating by example of Ni sorption on montmorillonite/bentonite. This includes 1) a summary of the present state of the art of thermodynamic sorption modeling, 2) a discussion of the selection of surface species and model design appropriate for the present purpose, 3) possible sources and representations of TSM uncertainties, and 4) details of modeling, testing and uncertainty evaluation for Ni sorption. Two fundamentally different approaches are presented and compared for representing TSM uncertainties: 1) TSM parameter uncertainties calculated by FITEQL optimization routines and some statistical procedure, 2) overall error estimated by direct comparison of modeled and experimental K d values. The overall error in K d is viewed as the best representation of model uncertainty in ISD model/database development. (author)

  4. Gas Sorption, Diffusion, and Permeation in Nafion

    KAUST Repository

    Mukaddam, Mohsin Ahmed; Litwiller, Eric; Pinnau, Ingo

    2015-01-01

    The gas permeability of dry Nafion films was determined at 2 atm and 35 °C for He, H2, N2, O2, CO2, CH4, C2H6, and C3H8. In addition, gas sorption isotherms were determined by gravimetric and barometric techniques as a function of pressure up to 20

  5. Development of a microminiature sorption cooler

    NARCIS (Netherlands)

    Burger, Johannes; Holland, Harry; ter Brake, Marcel; Rogalla, Horst; Wade, Larry

    1997-01-01

    The development of a microcooler for operations below 80 K, for low temperature electronic devices requiring small cooling powers of the order of 10 mW is described. A sorption compressor combined with Joule-Thomson (JT) expansion was selected for miniaturization. The advantage of the system is

  6. Sorption of radiocalcium on human hair

    International Nuclear Information System (INIS)

    Rakovic, M.; Pilecka, N.

    1987-01-01

    The sorption of 45 Ca on hair from a 45 CaCl 2 solution (2.5x10 -3 mol l -1 ) was studied. The calcium amounts sorbed in 1 min to 5 h range between 0.8 and 7.2% with respect to the originally present calcium in hair. (author) 3 refs

  7. Sorption of methanol in alkali exchange zeolites

    NARCIS (Netherlands)

    Rep, M.; Rep, M.; Corma, Avelino; Palomares, A.E.; Palomares gimeno, A.E.; van Ommen, J.G.; Lefferts, Leonardus; Lercher, J.A.

    2000-01-01

    Metal cation methanol sorption complexes in MFI (ZSM5), MOR and X have been studied by in situ i.r. spectroscopy in order to understand the nature of interactions of methanol in the molecular sieve pores. The results show that (a) a freely vibrating hydroxy and methyl group of methanol exist on

  8. Benzene and MTBE Sorption in Fine Grain Sediments

    Science.gov (United States)

    Leal-Bautista, R. M.; Lenczewski, M. E.

    2003-12-01

    The practice of adding methyl tert-butyl ether (MTBE) to gasoline started in the late 1970s and increased dramatically in the 1990s. MTBE first was added as a substitute for tetra-ethyl lead then later as a fuel oxygenate. Although the use of MTBE has resulted in significant reduction in air pollution, it has become a significant groundwater contaminant due to its high solubility in water, high environmental mobility, and low potential for biodegradation. A recent report (1999-2001) by the Metropolitan Water District of Southern California in collaboration with United State Geological Survey and the Oregon Health and Science University found that MTBE was the second most frequent detected volatile organic compound in groundwater. In Illinois, MTBE has been found in 26 of the 1,800 public water supplies. MTBE has also been blended in Mexico into two types of gasoline sold in the country by the state oil company (PEMEX) but is not monitored in groundwater at this time. Early research on MTBE considered it unable to adsorb to soils and sediments, however, by increasing the organic matter and decreasing the size of the grains (silts or clays) this may increase sorption. The objective of this study is to determine if fine grained materials have the potential for sorption of MTBE due to its high specific surface area (10-700 m 2/g) and potentially high organic matter (0.5-3.8%). The experiment consisted of sorption isotherms to glacial tills from DeKalb, Illinois and lacustrine clays from Chalco, Mexico. Experiments were performed with various concentrations of MTBE and benzene (10, 50, 100, 500 and 1000 ug/L) at 10° C and 25° C. Results showed a range of values for the distribution coefficient (Kd, linear model). At 10° C the Kd value for MTBE was 0.187 mL/g for lacustrine clay while the glacial loess had a value of 0.009 mL/g. The highest Kd values with MTBE were 0.2859 mL/g for organic rich lacustrine clays and 0.014 mL/g for glacial loess at 25° C. The highest

  9. Radionuclide sorption kinetics and column sorption studies with Columbia River basalts

    International Nuclear Information System (INIS)

    Barney, G.S.

    1983-09-01

    The kinetics of radionuclide sorption and desorption reactions in basalt-groundwater systems were evaluated at 60 degrees C using a batch equilibration method. It was found that many sorption reactions on surfaces of fresh (unaltered) basalt from the Umtanum and Cohassett flows are slow. Some reactions require more than 50 days to reach a steady state. Sorption of neptunium and uranium in oxidizing (air saturated) groundwater appears to be controlled by slow reduction of these elements by the basalt surfaces. The resulting lower oxidation states are more strongly sorbed. Technetium and selenium, which are anionic under oxidizing conditions, are not measurably sorbed on fresh basalt surfaces, but are slightly sorbed on the altered surfaces of flow top basalt. Under reducing conditions, where the groundwater contains dilute hydrazine, sorption is faster for neptunium, uranium, technetium, selenium, and lead. Plutonium sorption rates were not affected by the groundwater Eh. It was shown that radium was precipitated rather than sorbed under the conditions of these experiments. Umtanum flow top material sorbed radionuclides much faster than fresh basalt surfaces due to its greater surface area and cation exchange capacity. Desorption rates for plutonium, uranium, neptunium, technetium, and selenium were generally much less than sorption rates (especially for reducing conditions). These radionuclides are irreversibly sorbed on the basalts. 25 refs., 20 figs., 19 tabs

  10. Radionuclide sorption on crushed and intact granitic rock

    International Nuclear Information System (INIS)

    Eriksen, Tryggve E.; Locklund, Birgitta

    1989-05-01

    The specific surface areas and distribution ratios for sorption of 85 Sr, 137 Cs and 152 Eu were measured for crushed and intact granite rock. The experimental data can be accommodated by a sorption model encompassing sorption on outer and inner surface. It is clearly demonstrated that the time required to obtain reliable Kd-values for the sorption of strongly sorbing radionuclides like 152 Eu is very long due to solution depletion and slow diffusion into the rock. A combination of surface area measurements and batch sorption with small particles may therefore be preferable when studying strongly sorbing nuclides. (authors) (17 figs., 6 tabs.)

  11. Sorption and migration of neptunium in porous sedimentary materials

    International Nuclear Information System (INIS)

    Tanaka, Tadao; Mukai, Masayuki; Nakayama, Shinichi

    2005-01-01

    Column migration experiments of neptunium were conducted for porous sedimentary materials: coastal sand, tuffaceous sand, ando soil, reddish soil, yellowish soil and loess, and migration behavior, sorption mechanisms and chemical formation of Np were investigated. The migration behavior of Np in each material was much different each other, due to chemical formation in solution and/or sorption mechanism of Np. Mathematical models of different concepts were applied to the experimental results to interpret the sorption mechanism and the migration behavior. It can be concluded that both of instantaneous equilibrium sorption and sorption-desorption kinetics have to be considered to model the Np migration in sedimentary materials. (author)

  12. Transport Coefficients of Fluids

    CERN Document Server

    Eu, Byung Chan

    2006-01-01

    Until recently the formal statistical mechanical approach offered no practicable method for computing the transport coefficients of liquids, and so most practitioners had to resort to empirical fitting formulas. This has now changed, as demonstrated in this innovative monograph. The author presents and applies new methods based on statistical mechanics for calculating the transport coefficients of simple and complex liquids over wide ranges of density and temperature. These molecular theories enable the transport coefficients to be calculated in terms of equilibrium thermodynamic properties, and the results are shown to account satisfactorily for experimental observations, including even the non-Newtonian behavior of fluids far from equilibrium.

  13. Investigation of strontium and uranium sorption onto zirconium-antimony oxide/polyacrylonitrile (Zr-Sb oxide/PAN) composite using experimental design

    Energy Technology Data Exchange (ETDEWEB)

    Cakir, Pelin; Inan, Suleyman, E-mail: suleyman.inan@ege.edu.tr; Altas, Yuksel

    2014-04-01

    Highlights: • We model Sr{sup 2+} and UO{sub 2}{sup 2+} sorption onto Zr-Sb oxide/PAN composite. • Central composite design was separately employed for Sr{sup 2+} and UO{sub 2}{sup 2+} sorption. • The model F values indicate that both models are statistically significant. • All of the single factors were determined as significant for the sorption of Sr{sup 2+} and UO{sub 2}{sup 2+}. • Zr-Sb oxide/PAN can be used effectively for Sr{sup 2+} and UO{sub 2}{sup 2+} removal from acidic solutions. - Abstract: A study on the sorption of strontium (Sr{sup 2+}) and uranium (UO{sub 2}{sup 2+}) onto zirconium-antimony oxide/PAN (Zr-Sb oxide/PAN) composite was conducted. The zirconium-antimony oxide was synthesized and was then turned into composite spheres by mixing it with polyacrylonitrile (PAN). The single and combined effects of independent variables such as initial pH, temperature, initial ion concentration and contact time on the sorption of Sr{sup 2+} and UO{sub 2}{sup 2+} were separately analyzed using response surface methodology (RSM). Central composite design (CCD) was separately employed for Sr{sup 2+} and UO{sub 2}{sup 2+} sorption. Analysis of variance (ANOVA) revealed that all of the single effects found statistically significant on the sorption of Sr{sup 2+} and UO{sub 2}{sup 2+}. Probability F-values (F = 2.45 × 10{sup −08} and F = 9.63 × 10{sup −12} for Sr{sup 2+} and UO{sub 2}{sup 2+}, respectively) and correlation coefficients (R{sup 2} = 0.96 for Sr{sup 2+} and R{sup 2} = 0.98 for UO{sub 2}{sup 2+}) indicate that both models fit the experimental data well. At optimum sorption conditions Sr{sup 2+} and UO{sub 2}{sup 2+} sorption capacities of the composite were found as 39.78 and 60.66 mg/g, respectively. Sorption isotherm data pointed out that Langmuir model is more suitable for the Sr{sup 2+} sorption, whereas the sorption of UO{sub 2}{sup 2+} was correlated well with the Langmuir and Freundlich models. Thermodynamic parameters such as

  14. Sorption and Transport of Pharmaceutical chemicals in Organic- and Mineral-rich Soils

    Science.gov (United States)

    Vulava, V. M.; Schwindaman, J.; Murphey, V.; Kuzma, S.; Cory, W.

    2011-12-01

    OC, again indicating that these PhACs preferentially partition into the soil OM. Such a correlation was absent for cetirizine. Breakthrough curves of PhACs measured in homogeneous packed soil columns indicated that PhAC transport was affected by chemical nonequilibrium processes depending on the soil and PhAC chemistry. The shape of the breakthrough curves indicated that there were two distinct sorption sites - OM and clay minerals - which influence nonequilibrium transport of these compounds. The retardation factor estimated using the distribution coefficient, Kd, measured from the sorption experiments was very similar to the measured value. While the sorption and transport data do not provide mechanistic information regarding the nature of PhAC interaction with chemical reactive components within geological materials, they do provide important information regarding potential fate of such compounds in the environment. The results also show the role that soil OM and mineral surfaces play in sequestering or transporting these chemicals. These insights have implications to the quality of the water resources in our communities.

  15. Sorption characteristics of honeycomb type sorption element composed of organic sorbent; Yukikei shuchakuzai wo tofushita honeycomb jo shuchaku element nio shuchaku tokuse

    Energy Technology Data Exchange (ETDEWEB)

    Inaba, H.; Horibe, A. [Okayama University, Okayama (Japan); Kida, T.; Kaneda, M. [Japan Exlan Co. Ltd., Osaka (Japan)

    2000-12-25

    This paper has dealt with the sorption characteristics of honeycomb shape type sorbent element composed of new organic sorbent which was composed of the bridged complex of sodium polyacrylate. The transient experiments in which the moist air was passed into the honeycomb type sorbent element were conducted under various conditions of air velocity, temperature, relative-humidity and honeycomb length. As a result, the effective mass transfer coefficient of the organic sorbent sorbing the water-vapor was non-dimensionalized as a function of Reynolds number, modified Stefan number and non-dimensional honeycomb length. (author)

  16. Modeling Fission Product Sorption in Graphite Structures

    International Nuclear Information System (INIS)

    Szlufarska, Izabela; Morgan, Dane; Allen, Todd

    2013-01-01

    The goal of this project is to determine changes in adsorption and desorption of fission products to/from nuclear-grade graphite in response to a changing chemical environment. First, the project team will employ principle calculations and thermodynamic analysis to predict stability of fission products on graphite in the presence of structural defects commonly observed in very high-temperature reactor (VHTR) graphites. Desorption rates will be determined as a function of partial pressure of oxygen and iodine, relative humidity, and temperature. They will then carry out experimental characterization to determine the statistical distribution of structural features. This structural information will yield distributions of binding sites to be used as an input for a sorption model. Sorption isotherms calculated under this project will contribute to understanding of the physical bases of the source terms that are used in higher-level codes that model fission product transport and retention in graphite. The project will include the following tasks: Perform structural characterization of the VHTR graphite to determine crystallographic phases, defect structures and their distribution, volume fraction of coke, and amount of sp2 versus sp3 bonding. This information will be used as guidance for ab initio modeling and as input for sorptivity models; Perform ab initio calculations of binding energies to determine stability of fission products on the different sorption sites present in nuclear graphite microstructures. The project will use density functional theory (DFT) methods to calculate binding energies in vacuum and in oxidizing environments. The team will also calculate stability of iodine complexes with fission products on graphite sorption sites; Model graphite sorption isotherms to quantify concentration of fission products in graphite. The binding energies will be combined with a Langmuir isotherm statistical model to predict the sorbed concentration of fission products

  17. SORPTION OF Au(III BY Saccharomyces cerevisiae BIOMASS

    Directory of Open Access Journals (Sweden)

    Amaria Amaria

    2010-07-01

    Full Text Available Au(III sorption by S. cerevisiae biomass extracted from beer waste industry was investigated. Experimentally, the sorption was conducted in batch method. This research involved five steps: 1 identification the functional groups present in the S. cerevisiae biomass by infrared spectroscopic technique, 2 determination of optimum pH, 3 determination of the sorption capacity and energy, 4 determination of the sorption type by conducting desorption of sorbed Au(III using specific eluents having different desorption capacity such as H2O (van der Waals, KNO3 (ion exchange, HNO3 (hydrogen bond, and tiourea (coordination bond, 5 determination of effective eluents in Au(III desorption by partial desorption of sorbed Au(III using thiourea, NaCN and KI. The remaining Au(III concentrations in filtrate were analyzed using Atomic Absorption Spectrophotometer. The results showed that: 1 Functional groups of S. cerevisiae biomass that involved in the sorption processes were hydroxyl (-OH, carboxylate (-COO- and amine (-NH2, 2 maximum sorption was occurred at pH 4, equal to 98.19% of total sorption, 3 The sorption capacity of biomass was 133.33 mg/g (6.7682E-04 mol/g and was involved sorption energy 23.03 kJ mol-1, 4 Sorption type was dominated by coordination bond, 5 NaCN was effective eluent to strip Au(III close to 100%.   Keywords: sorption, desorption, S. cerevisiae biomass, Au(III

  18. Modeling volatile organic compounds sorption on dry building materials using double-exponential model

    International Nuclear Information System (INIS)

    Deng, Baoqing; Ge, Di; Li, Jiajia; Guo, Yuan; Kim, Chang Nyung

    2013-01-01

    A double-exponential surface sink model for VOCs sorption on building materials is presented. Here, the diffusion of VOCs in the material is neglected and the material is viewed as a surface sink. The VOCs concentration in the air adjacent to the material surface is introduced and assumed to always maintain equilibrium with the material-phase concentration. It is assumed that the sorption can be described by mass transfer between the room air and the air adjacent to the material surface. The mass transfer coefficient is evaluated from the empirical correlation, and the equilibrium constant can be obtained by linear fitting to the experimental data. The present model is validated through experiments in small and large test chambers. The predicted results accord well with the experimental data in both the adsorption stage and desorption stage. The model avoids the ambiguity of model constants found in other surface sink models and is easy to scale up

  19. Soil Properties Control Glyphosate Sorption in Soils Amended with Birch Wood Biochar

    DEFF Research Database (Denmark)

    Kahawaththa Gamage, Inoka Damayanthi Kumari; Moldrup, Per; Paradelo, Marcos

    2016-01-01

    Abstract Despite a contemporary interest in biochar application to agricultural fields to improve soil quality and long-term carbon sequestration, a number of potential side effects of biochar incorporation in field soils remain poorly understood, e.g., in relation to interactions...... with agrochemicals such as pesticides. In a fieldbased study at two experimental sites in Denmark (sandy loam soils at Risoe and Kalundborg), we investigated the influence of birch wood biochar with respect to application rate, aging (7–19 months), and physico- chemical soil properties on the sorption coefficient......, Kd (L kg−1), of the herbicide glyphosate. We measured Kd in equilibrium batch sorption experiments with triplicate soil samples from 20 field plots that received biochar at different application rates (0 to 100 Mg ha−1). The results showed that pure biochar had a lower glyphosate Kd value as compared...

  20. [Impact of biochar amendment on the sorption and dissipation of chlorantraniliprole in soils].

    Science.gov (United States)

    Wang, Ting-Ting; Yu, Xiang-Yang; Shen, Yaen; Zhang, Chao-Lan; Liu, Xian-Jin

    2012-04-01

    The effects of biochar amendment on sorption and dissipation of chlorantraniliprole (CAP) in 5 different agricultural soils were studied. Red gum wood (Eucalyptus spp.) derived biochar was amended into a black soil, a yellow soil, a red soil, a purplish soil, and a fluvo-aquic soil at the rate of 0.5% (by weight). The sorption and dissipation behaviors of CAP in soils with and without biochar amendment were measured by batch equilibration technique and dissipation kinetic experiment, respectively. The objective was to investigate the impact of biochar application on the environmental fate of pesticides in agricultural soils with different physical-chemical properties, and evaluate the potential ecological impacts of field application of biochar materials. The results showed that biochar application in soils could enhance the sorption of CAP, but the magnitudes were varied among soils with different properties. Amendment of 0.5% (by weight) biochar in the black soil, which have high content of organic matter (4.59%), resulted in an increase of sorption coefficient (K(d)) by 2.17%; while for the fluvo-aquic soil with organic matter content of 1.16%, amendment of biochar at the same level led to an increase of 139.13%. The sorption capacity of biochar was partially suppressed when biochar was mixed with soils. The calculated K(Fbiochar) of biochar after mixed in the black soil, yellow soil, red soil, purplish soil, and fluvo-aquic soil were decreased by 96.94%, 90.6%, 91.31%, 68.26%, and 34.59%, respectively, compared to that of the original biochar. The half-lives of CAP in black soil, yellow soil, red soil, purplish soil, and fluvo-aquic soil were 115.52, 133.30, 154.03, 144.41 and 169.06 d, respectively. In soils amended with biochar, the corresponding half-lives of CAP were extended by 20.39, 35.76, 38.51, 79.19, and 119.75 d, respectively. Similar to the effects of biochar on CAP sorption, in soil with higher content of organic matter, the retardation of CAP

  1. Thermodynamic sorption modelling in support of radioactive waste disposal safety cases - NEA sorption project phase III

    International Nuclear Information System (INIS)

    2012-01-01

    A central safety function of radioactive waste disposal repositories is the prevention or sufficient retardation of radionuclide migration to the biosphere. Performance assessment exercises in various countries, and for a range of disposal scenarios, have demonstrated that one of the most important processes providing this safety function is the sorption of radionuclides along potential migration paths beyond the engineered barriers. Thermodynamic sorption models (TSMs) are key for improving confidence in assumptions made about such radionuclide sorption when preparing a repository's safety case. This report presents guidelines for TSM development as well as their application in repository performance assessments. They will be of particular interest to the sorption modelling community and radionuclide migration modellers in developing safety cases for radioactive waste disposal Contents: 1 - Thermodynamic sorption models and radionuclide migration: Sorption and radionuclide migration; Applications of TSMs in radioactive waste disposal studies; Requirements for a scientifically defensible, calibrated TSM applicable to radioactive waste disposal; Current status of TSMs in radioactive waste management; 2 - Theoretical basis of TSMs and options in model development: Conceptual building blocks of TSMs and integration with aqueous chemistry; The TSM representation of sorption and relationship with Kd values; Theoretical basis of TSMs; Example of TSM for uranyl sorption; Options in TSM development; Illustration of TSM development and effects of modelling choices; Summary: TSMs for constraining Kd values - impact of modelling choices; 3 - Determination of parameters for TSMs: Overview of experimental determination of TSM parameters; Theoretical estimation methods of selected model parameters; Case study: sorption modelling of trivalent lanthanides/actinides on illite; Indicative values for certain TSM parameters; Parameter uncertainty; Illustration of parameter sensitivity

  2. An Exact Solution for the Assessment of Nonequilibrium Sorption of Radionuclides in the Vadose Zone

    International Nuclear Information System (INIS)

    Drake, R. L.; Chen, J-S.

    2002-01-01

    In a report on model evaluation, the authors ran the HYDRUS Code, among other transport codes, to evaluate the impacts of nonequilibrium sorption sites on the time-evolution of 99Tc and 90Sr through the vadose zone. Since our evaluation was based on a rather low, annual recharge rate, many of the numerical results derived from HYDRUS indicated that the nonequilibrium sorption sites, in essence, acted as equilibrium sorption sites. To help explain these results, we considered a ''stripped-down'' version of the HYDRUS system. This ''stripped-down'' version possesses two dependent variables, one for the radionuclides in solution and the other for the radionuclides adsorbed to the nonequilibrium sites; and it possesses constant physical parameters. The resultant governing equation for the radionuclides in solution is a linear, advection-dispersion-reaction (i.e., radioactive decay) partial differential equation containing a history integral term accounting for the nonequilibrium sorption sites. It is this ''stripped-down'' version, which is the subject of this paper. We found an exact solution to this new version of the model. The exact solution is given in terms of a single definite integral of terms involving elementary functions of the independent variables and the system parameters. This integral possesses adequate convergence properties and is easy to evaluate, both in a quantitative matter and in a qualitative manner. The parameters that are considered in the system are as follows: the radionuclide's equilibrium partition coefficient between water and soil, the bulk density of the soil, the fractions of equilibrium/nonequilibrium sorption sites, the volumetric water content, the first order equilibrium adsorption rate constant, the first order radioactive decay rate constant, the liquid water soil tortuosity factor, the molecular diffusion coefficient in water, the longitudinal dispersivity factor, and the Darcian fluid flux density. In addition, the system

  3. Kinetics of phosphorus sorption in soils in the state of Paraíba¹

    Directory of Open Access Journals (Sweden)

    Hemmannuella Costa Santos

    2011-08-01

    Full Text Available The soil P sorption capacity has been studied for many years, but little attention has been paid to the rate of this process, which is relevant in the planning of phosphate fertilization. The purpose of this experiment was to assess kinetics of P sorption in 12 representative soil profiles of the State of Paraíba (Brazil, select the best data fitting among four equations and relate these coefficients to the soil properties. Samples of 12 soils with wide diversity of physical, chemical and mineralogical properties were agitated in a horizontal shaker, with 10 mmo L-1 CaCl2 solution containing 6 and 60 mg L-1 P, for periods of 5, 15, 30, 45, 60, 90, 120, 420, 720, 1,020, and 1,440 min. After each shaking period, the P concentration in the equilibrium solution was measured and three equations were fitted based on the Freundlich equation and one based on the Elovich equation, to determine which soil had the highest sorption rate (kinetics and which soil properties correlated to this rate. The kinetics of P sorption in soils with high maximum P adsorption capacity (MPAC was fast for 30 min at the lower initial P concentration (6 mg L-1. No difference was observed between soils at the higher initial P concentration (60 mg L-1. The P adsorption kinetics were positively correlated with clay content, MPAC and the amount of Al extracted with dithionite-citrate-bicarbonate. The data fitted well to Freundlich-based equations equation, whose coefficients can be used to predict P adsorption rates in soils.

  4. Sorption of 17b-Estradiol to Pig Slurry Separates and Soil in the Soil-Slurry Environment

    DEFF Research Database (Denmark)

    Amin, Mostofa; Petersen, Søren O; Lægdsmand, Mette

    2012-01-01

    to agricultural soils, to different size fractions of pig slurry separates, and to soils amended with each size fraction to simulate conditions in the soil–slurry environment. A crude fiber fraction (SS1) was prepared by sieving (solids removed by an on-farm separation process. Three other size...... fractions (SS2 > SS3 > SS4) were prepared from the liquid fraction of the separated slurry by sedimentation and centrifugation. Sorption experiments were conducted in 0.01 mol L−1 CaCl2 and in natural pig urine matrix. Sorption in 0.01 mol L−1 CaCl2 was higher than that in pig urine for all solids used....... Sorption of E2 to soil increased with its organic carbon content for both liquid phases. The solid–liquid partition coefficients of slurry separates were 10 to 30 times higher than those of soils, but the organoic carbon normalized partition coefficient values, reflecting sorption per unit organic carbon...

  5. Defluoridation by Bacteriogenic Iron Oxides: Sorption Studies

    Science.gov (United States)

    Evans, K.; Ferris, F.

    2009-05-01

    At concentrations above 1 mg/L, fluoride in drinking water can lead to dental and skeletal fluorosis, a disease that causes mottling of the teeth, calcification of ligaments, crippling bone deformities and many other physiological disorders that can, ultimately, lead to death. Conservative estimates are that fluorosis afflicts tens of millions of people worldwide. As there is no treatment for fluorosis, prevention is the only means of controlling the disease. While numerous defluoridation techniques have been explored, no single method has been found to be both effective and inexpensive enough to implement widely. Our research began in India, with a large-scale geochemical study of the groundwater in a fluoride-contaminated region of Orissa. Having developed a better understanding of the geochemical relationships that exist between fluoride and other parameters present in an affected area, as well as the complex relationships that arise among those parameters that can impact the presence of fluoride, we began investigating certain remediation scenarios involving iron oxides. A common approach to remediation involves the partitioning of fluoride from groundwater by sorption onto a variety of materials, one of the most effective of which is iron oxide whose surface area acts as a scavenger for fluoride. In the presence of iron oxidizing bacteria, the oxidation rate of iron has been shown to be ˜6 times greater than in their absence; fluoride should, therefore, be removed from an aqueous environment by bacteriogenic iron oxides (BIOS) much more quickly than by abiotic iron oxides. Most recently, sorption studies have been conducted using both BIOS and synthetic hydrous ferric oxides in order to compare the behavior between biotic and abiotic sorbents. These studies have provided sorption isotherms that allow comparison of fluoride removed by sorption to BIOS versus synthetic iron oxides. Sorption affinity constants have also been determined, which allow for the

  6. Isotherm, kinetic, and thermodynamic study of ciprofloxacin sorption on sediments.

    Science.gov (United States)

    Mutavdžić Pavlović, Dragana; Ćurković, Lidija; Grčić, Ivana; Šimić, Iva; Župan, Josip

    2017-04-01

    In this study, equilibrium isotherms, kinetics and thermodynamics of ciprofloxacin on seven sediments in a batch sorption process were examined. The effects of contact time, initial ciprofloxacin concentration, temperature and ionic strength on the sorption process were studied. The K d parameter from linear sorption model was determined by linear regression analysis, while the Freundlich and Dubinin-Radushkevich (D-R) sorption models were applied to describe the equilibrium isotherms by linear and nonlinear methods. The estimated K d values varied from 171 to 37,347 mL/g. The obtained values of E (free energy estimated from D-R isotherm model) were between 3.51 and 8.64 kJ/mol, which indicated a physical nature of ciprofloxacin sorption on studied sediments. According to obtained n values as measure of intensity of sorption estimate from Freundlich isotherm model (from 0.69 to 1.442), ciprofloxacin sorption on sediments can be categorized from poor to moderately difficult sorption characteristics. Kinetics data were best fitted by the pseudo-second-order model (R 2  > 0.999). Thermodynamic parameters including the Gibbs free energy (ΔG°), enthalpy (ΔH°) and entropy (ΔS°) were calculated to estimate the nature of ciprofloxacin sorption. Results suggested that sorption on sediments was a spontaneous exothermic process.

  7. Testosterone sorption and desorption: Effects of soil particle size

    Energy Technology Data Exchange (ETDEWEB)

    Qi, Yong, E-mail: yqi01@unomaha.edu [Civil Engineering Dept., University of Nebraska-Lincoln at Omaha Campus, Omaha, NE 68182 (United States); Zhang, Tian C. [Civil Engineering Dept., University of Nebraska-Lincoln at Omaha Campus, Omaha, NE 68182 (United States); Ren, Yongzheng [School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China)

    2014-08-30

    Graphical abstract: - Highlights: • Smaller soil particles have higher sorption and lower desorption rates. • The sorption capacity ranks as clay > silt > sand. • Small particles like clays have less potential for desorption. • Colloids (clays) have high potential to facilitate the transport of hormones in soil–water environments. - Abstract: Soils contain a wide range of particles of different diameters with different mobility during rainfall events. Effects of soil particles on sorption and desorption behaviors of steroid hormones have not been investigated. In this study, wet sieve washing and repeated sedimentation methods were used to fractionate the soils into five ranges. The sorption and desorption properties and related mechanisms of testosterone in batch reactors filled with fractionated soil particles were evaluated. Results of sorption and desorption kinetics indicate that small soil particles have higher sorption and lower desorption rates than that of big ones. Thermodynamic results show the sorption processes are spontaneous and exothermal. The sorption capacity ranks as clay > silt > sand, depending mainly on specific surface area and surface functional groups. The urea control test shows that hydrogen bonding contributes to testosterone sorption onto clay and silt but not on sand. Desorption tests indicate sorption is 36–65% irreversible from clay to sand. Clays have highest desorption hysteresis among these five soil fractions, indicating small particles like clays have less potential for desorption. The results provide indirect evidence on the colloid (clay)-facilitated transport of hormones (micro-pollutants) in soil environments.

  8. Standard test method for distribution coefficients of inorganic species by the batch method

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2010-01-01

    1.1 This test method covers the determination of distribution coefficients of chemical species to quantify uptake onto solid materials by a batch sorption technique. It is a laboratory method primarily intended to assess sorption of dissolved ionic species subject to migration through pores and interstices of site specific geomedia. It may also be applied to other materials such as manufactured adsorption media and construction materials. Application of the results to long-term field behavior is not addressed in this method. Distribution coefficients for radionuclides in selected geomedia are commonly determined for the purpose of assessing potential migratory behavior of contaminants in the subsurface of contaminated sites and waste disposal facilities. This test method is also applicable to studies for parametric studies of the variables and mechanisms which contribute to the measured distribution coefficient. 1.2 The values stated in SI units are to be regarded as standard. No other units of measurement a...

  9. Effect of grain size on the sorption and desorption of SeO42- and SeO32- in columns of crushed granite and fracture infill from granitic water under dynamic conditions

    International Nuclear Information System (INIS)

    Videnska, K.; Institute of Chemical Technology, Prague; Palagyi, S.; Czech Technical University, Prague; Stamberg, K.; Vodickova, H.; Havlova, V.

    2013-01-01

    The sorption of 2 x 10 -5 mol/dm 3 Na 2 SeO 4 and Na 2 SeO 3 dissolved in synthetic granitic water (SGW) were investigated in columns of crushed granite and fracture infill (clay minerals) of various grain sizes. Desorption was studied using pure SGW. The goal of study was the quantification of the effect of grain size on the retardation and distribution coefficients of SeO 4 2- and SeO 3 2- , as well as on the other transport parameters (Peclet number and hydrodynamic dispersion coefficient). A model based on the erfc-function, assuming a non-linear reversible equilibrium sorption/desorption isotherm, was used for evaluation of sorption/desorption and transport parameters. The determination of selenium was performed using an ICP-MS technique. The experimental breakthrough curves were fitted using non-linear regression procedure, in the course of which the parameters mentioned were sought. Summing up, no sorption was recorded in the case of SeO 4 2- under these conditions. The values of retardation coefficients were practically one for all studied grain sizes. On the other hand, significant sorption was found for SeO 3 2- : depending on the grain size, the retardation coefficients varied between 1.6-8.7 in pure granite and 1.8-37.2 in infill materials. These values correspond to distribution coefficients of 0.2-2.5 and 0.2-12.7 cm 3 /g, respectively. The both parameters have similar values in a case of desorption which reflects the reversible character of sorption process. It was found that retardation and distribution coefficients and sorption capacity for SeO 3 2- also increase with decreasing grain size. (author)

  10. Effect of natural organic materials on cadmium and neptunium sorption

    International Nuclear Information System (INIS)

    Kung, K.S.; Triay, I.R.

    1994-01-01

    In a batch sorption study of the effect of naturally occurring organic materials on the sorption of cadmium and neptunium on oxides and tuff surfaces, the model sorbents were synthetic goethite, boehmite, amorphous silicon oxides, and a crushed tuff material from Yucca Mountain, Nevada. An amino acid, 3-(3,4-dihydroxypheny)-DL-alanine (DOPA), and an aquatic-originated fulvic material, Nordic aquatic fulvic acid (NAFA), were used as model organic chemicals. Sorption isotherm results showed that DOPA sorption followed the order aluminum oxide > iron oxide > silicon oxide and that the amount of DOAP sorption for a given sorbent increased as the solution pH was raised. The sorption of cadmium and neptunium on the iron oxide was about ten times higher than that on the aluminum oxide. The sorption of cadmium and neptunium on natural tuff material was much lower than that on aluminum and iron oxides. The sorption of cadmium on iron and aluminum oxides was found to be influenced by the presence of DOPA, and increasing the amount of DOPA coating resulted in higher cadmium sorption on aluminum oxide. However, for iron oxide, cadmium sorption decreased with increasing DOPA concentration. The presence of the model organic materials DOPA and NAFA did not affect the sorption of neptunium on tuff material or on the iron and aluminum oxides. Spectroscopic results indicate that cadmium complexes strongly with DOPA. Therefore, the effect of the organic material, DOPA, on the cadmium sorption is readily observed. However, neptunium is possibly complexed weakly with organic material. Thus, DOPA and NAFA have little effect on neptunium sorption on all sorbents selected for study

  11. Sorption analyses in materials science: selected oxides

    International Nuclear Information System (INIS)

    Fuller, E.L. Jr.; Condon, J.B.; Eager, M.H.; Jones, L.L.

    1981-01-01

    Physical adsorption studies have been shown to be extremely valuable in studying the chemistry and structure of dispersed materials. Many processes rely on the access to the large amount of surface made available by the high degree of dispersion. Conversely, there are many applications where consolidation of the dispersed solids is required. Several systems (silica gel, alumina catalysts, mineralogic alumino-silicates, and yttrium oxide plasters) have been studied to show the type and amount of chemical and structural information that can be obtained. Some review of current theories is given and additional concepts are developed based on statistical and thermodynamic arguments. The results are applied to sorption data to show that detailed sorption analyses are extremely useful and can provide valuable information that is difficult to obtain by any other means. Considerable emphasis has been placed on data analyses and interpretation of a nonclassical nature to show the potential of such studies that is often not recognized nor utilized

  12. Sorption of zinc on human teeth

    International Nuclear Information System (INIS)

    Helal, A.; Amin, H.; Alian, G.

    1997-01-01

    Zinc containing dental amalgams are sometimes used as fillings by dentists. The freshly mixed mass of the amalgam alloy and liquid mercury packed or condensed into a prepared tooth cavity. Zinc has been included in amalgams alloys up to 2% as an aid in manufacturing by helping to produce clean sound castings of the ingots. Although such restorations have a relatively long service life, they are subject to corrosion and galvanic action, thus releasing metallic products into the oral environment. The aim of this paper is to investigate the uptake (sorption) of Zinc ionic species on human teeth using the radioactive tracer technique. For this purpose the isotope Zn-65 produced from pile-irradiation of zinc metal was used. The various liquids studied were drinking water (tap water), tea, coffee, red tea and chicken soup. Sorption was studied through immersion of a single human tooth (extracted) in each of these liquids

  13. Sorption of 60 Co on inorganic solids

    International Nuclear Information System (INIS)

    Granados C, F.; Bulbulian G, S.; Mardel V, B.

    2003-01-01

    The behavior of sorption of the 60 Co in aqueous solution under static conditions to different values of pH of the aqueous solution (1, 3, 5, 7, and 10) on MgO, MnO 2 , SnO, TiO 2 , activated carbon and calcinate hydrotalcite was investigated. It was found that the best sorbents of the 60 Co was the MnO 2 , activated carbon and TiO 2 whose sorption was incremented when increasing the pH value of the aqueous solutions, in the one case of the hydrated oxides, the 60 Co interacted with the electrically charged surface of the sorbents that depends on the pH of the solution and of the point of zero charge (zpc) of the sorbent. (Author)

  14. Noble metal extraction and sorption concentrating

    International Nuclear Information System (INIS)

    Petrukhin, O.M.; Malofeeva, G.I.

    1985-01-01

    Works performed in the USSR Academy of Sciences GEOCHI laboratory of extraction methods and devoted to selectivity problems of extraction and sorption methods of platinum metal, cadmium and indium concentrating in analytical chemistry are discussed. On choosing complexino. reagent main attention is paid to the selectivity variation based on different stability of metal complexes. Platinum metals are extracted in the form of ion associates when usinq hard, mainly oxyqen-containing, extractants. Coordination-solvated metal complexes are extracted white usinq extractants containing sulfur, trivalent phosphorus and aromatic nitroqen as donor anions. Selectivity is maximum for sulfur- and nitroren-containinq extractants and sorbents. In case of the group extraction of platinum metals sorption is preferable and in case of selective extraction of individual metals, especially, in case of need of relative concentratinq extraction is preferable

  15. Uranium sorption on tezontle volcanic rock

    International Nuclear Information System (INIS)

    Lopez M, B. E.; Duran B, J. M.; Iturbe G, J. L.; Olguin G, M. T.

    2009-01-01

    It is described a study that demonstrates that hexavalent uranium ions were sorbed by the naturally occurring mineral using a batch technique. This mineral is found in abundant quantities in Mexico. Our study focused on the separation of U Vi from synthetic aqueous systems of both H 2 O-UO 2 (NO 3 ) 2 .6H 2 O (acid) and H 2 O-Na 4 [UO 2 (CO 3 ) 3 ] (basic). The chemical speciation was performed by using high voltage electrophoresis, and the uranium content was determined by UV-Vis spectroscopy. The quantified U(Vi) sorption by tezontle from acidic and basic systems was 2.72 and 1.68 μmol/g, respectively, and the sorption behavior is discussed considering the surface charge of the tezontle at different ph values based on the point of zero charge characteristic of this material. (Author)

  16. Sorption of radionuclides on London clay

    International Nuclear Information System (INIS)

    Berry, J.A.; Bourke, P.J.; Green, A.; Littleboy, A.K.

    1989-02-01

    Techniques for studying the sorption of radionuclides on London clay have been investigated. This work involved the use of through-diffusion, in-diffusion, high-pressure convection and batch methods to study the sorption of iodide, strontium, caesium and americium. Through-diffusion and high-pressure convection methods were found to be most useful for investigating weakly and moderately sorbing nuclides and give realistic values for sorptivity. The batch technique remains the most practical method of obtaining large quantities of data within a relatively short timescale but gives very high sorptivity values. It is however very useful for intercomparisons of nuclides or geological media. The in-diffusion method requires further refinement for use with strongly sorbing nuclides. Good agreement between through-diffusion and high-pressure convection methods was obtained for the sorptivity of strontium, whilst trends observed for caesium by through-diffusion were confirmed by batch measurements. (author)

  17. Positron Spectroscopy of Nanodiamonds after Hydrogen Sorption

    Directory of Open Access Journals (Sweden)

    Lyudmila Nikitina

    2018-01-01

    Full Text Available The structure and defects of nanodiamonds influence the hydrogen sorption capacity. Positronium can be used as a sensor for detecting places with the most efficient capture of hydrogen atoms. Hydrogenation of carbon materials was performed from gas atmosphere. The concentration of hydrogen absorbed by the sample depends on the temperature and pressure. The concentration 1.2 wt % is achieved at the temperature of 243 K and the pressure of 0.6 MPa. The hydrogen saturation of nanodiamonds changes the positron lifetime. Increase of sorption cycle numbers effects the positron lifetime, as well as the parameters of the Doppler broadening of annihilation line. The electron-positron annihilation being a sensitive method, it allows detecting the electron density fluctuation of the carbon material after hydrogen saturation.

  18. Sorption studies of radioelements on geological materials

    International Nuclear Information System (INIS)

    Berry, John A.; Yui, Mikazu; Kitamura, Akira

    2007-11-01

    Batch sorption experiments have been carried out to study the sorption of uranium, technetium, curium, neptunium, actinium, protactinium, polonium, americium and plutonium onto bentonite, granodiorite and tuff. Mathematical modelling using the HARPHRQ program and the HATCHES database was carried out to predict the speciation of uranium and technetium in the equilibrated seawater, and neptunium, americium and plutonium in the rock equilibrated water. Review of the literature for thermodynamic data for curium, actinium, protactinium and polonium was carried out. Where sufficient data were available, predictions of the speciation and solubility were made. This report is a summary report of the experimental work conducted by AEA Technology during April 1991-March 1998, and the main results have been presented at Material Research Society Symposium Proceedings and published as proceedings of them. (author)

  19. Robust Means for Estimating Black Carbon-Water Sorption Coefficients of Organic Contaminants in Sediments

    Science.gov (United States)

    2015-07-01

    compounds by black carbon, Springer, Dordrecht. Plata, D.L., Hemingway , J.D. and Gschwend, P.M. (2015) Polyparameter linear free energy relationship for...1320-1331. 32 8. Appendices Scientific/Technical Publications Plata, D.L., J.D. Hemingway , and P.M. Gschwend. Polyparameter linear free energy

  20. Physico-chemical characterisation and sorption measurements of Cs, Sr, Ni, Eu, Th, Sn and Se on Opalinus clay from Mont Terri

    International Nuclear Information System (INIS)

    Lauber, Matthias; Baeyens, Bart; Bradbury, Michael H.

    2000-12-01

    Opalinus Clay is currently under investigation as a potential host rock for the disposal of high level and long-lived intermediate radioactive waste. A throughout physico-chemical characterisation was carried out on a bore core sample from the underground rock laboratory Mont Terri (Canton Jura). The results of these investigations indicate that the major characteristics (mineralogy, cation exchange capacity, cation occupancies, selectivity coefficients, chloride and sulphate inventories) were very similar to a different core sample, previously used for pore water modelling studies. It was concluded that the pore water compositions derived in the earlier studies were reliable and could be used in this work. The organic matter which dissolved from the Opalinus Clay rock was not humic or fulvic acids and the concentration remaining in the liquid phase in the sorption experiments was < 0.5 ppm C. The organic matter is therefore considered to have little or no influence on the sorption behaviour of the studied radionuclides. Redox potential measurements of the Opalinus Clay/synthetic pore water system inside the glove boxes indicated anoxic conditions. The main focus of the experimental work presented here is on the sorption behaviour of Cs (I), Sr (II), Ni (II), Eu (III), Th (IV), Sn (IV) and Se (IV) on Opalinus Clay equilibrated with synthetic pore waters at pH 6.3 and 8. Sorption isotherms were measured for Cs, Ni, Eu, Th and Se. Single point data were measured for Sr and Sn. For all radionuclides studied the sorption kinetics were measured first. The times required to complete the sorption on the Opalinus Clay varied between one day for Th and one month for Ni and Se. Within the concentration ranges under study the uptake of Cs, Ni, Eu and Se on Opalinus Clay was non-linear, whereas for Th a linear sorption behaviour was observed. For Ni, Eu and Th the sorption increased with increasing pH. For Cs a pH independent sorption behaviour was observed. The concentration

  1. Sorption behaviour of herbicides in soils

    International Nuclear Information System (INIS)

    Luchini, L.C.; Wiendl, F.M.; Ruegg, E.F.; Instituto Biologico, Sao Paulo

    1988-01-01

    Environmental contamination by herbicides is related with the sorption phenomenon of these compounds in the soils. The behaviour of paraquat, 2,4-D and diuron was studied in soils with different physico-chemical properties, through the Freundlich adsorption and desorption isotherms, using 14 C-radiolabeled herbicides. Results of the range of the adsorption-desorption of each herbicide was related mainly with the chemical characteristics of these compounds. (author) [pt

  2. Phosphate sorption characteristics of European alpine soils

    Czech Academy of Sciences Publication Activity Database

    Kaňa, Jiří; Kopáček, Jiří; Camarero, L.; Garcia-Pausas, J.

    2011-01-01

    Roč. 75, č. 3 (2011), s. 862-870 ISSN 0361-5995 R&D Projects: GA ČR(CZ) GA526/09/0567; GA AV ČR(CZ) KJB600960907 Grant - others:EU EMERGE(CZ) EVK1-CT-1999-00032 Institutional research plan: CEZ:AV0Z60170517 Keywords : phosphate sorption * alpine soil s * acidification Subject RIV: DJ - Water Pollution ; Quality Impact factor: 1.979, year: 2011

  3. Moisture sorption isotherms of dehydrated whey proteins

    Directory of Open Access Journals (Sweden)

    Suzana Rimac Brnčić

    2010-03-01

    Full Text Available Moisture sorption isotherms describe the relation between the moisture content of the dry material (food and relative humidity of the surrounding environment. The data obtained are important in modelling of drying process conditions, packaging and shelf-life stability of food that will provide maximum retaining of aroma, colour and texture as well as nutritive and biological value. The objective of this research was to establish the equilibrium moisture content and water activity, as well as monolayer value of two commercial powdered whey protein isolates before and after tribomechanical micronisation and enzymatic hydrolysis, respectively. At the same time it was necessary to evaluate the best moisture sorption isotherm equation to fit the experimental data. The equilibrium moisture contents in investigated samples were determined using standard gravimetric method at 20 °C. The range of water activities was 0.11 to 0.75. The monolayer moisture content was estimated from sorption data using Brunauer-Emmett-Teller (BET and Guggenheim-Anderson-de Boer (GAB models. The results have shown that tribomechanically treated whey protein isolates as well as protein hydrolizates had lower monolayer moisture content values as well as higher corresponding water activity. Therefore, in spite of the fact that they have lower moisture content, they can be storage at higher relative humidity compared to untreated samples. BET model gave better fit to experimental sorption data for a water activity range from 0.11-0.54, while GAB model gave the closest fit for a water activity to 0.75.

  4. Moisture sorption isotherms of dehydrated whey proteins

    OpenAIRE

    Suzana Rimac Brnčić; Vesna Lelas; Zoran Herceg; Marija Badanjak

    2010-01-01

    Moisture sorption isotherms describe the relation between the moisture content of the dry material (food) and relative humidity of the surrounding environment. The data obtained are important in modelling of drying process conditions, packaging and shelf-life stability of food that will provide maximum retaining of aroma, colour and texture as well as nutritive and biological value. The objective of this research was to establish the equilibrium moisture content and water activity, as well as...

  5. Sorption studies of caesium by complex hexacyanoferrates

    International Nuclear Information System (INIS)

    Jacobi, D.

    1992-01-01

    A comprehensive literature review was carried out on the preparation of complex hexacyanoferrates in a granular form suitable for use in a packed column. The preparation of sodium nickel hexacyanoferrate using a freeze-thaw method was studied in detail and a method developed to produce a consistent and reproducible granular product. The equilibrium and sorption kinetics were studied using batch and column tests, and the process modelled to predict performance under various conditions. (author)

  6. Sorption and diffusion processes of long-lived radionuclides on natural sorbents

    International Nuclear Information System (INIS)

    Jedinakova-Krrizova, V.; Kohlickova, M; Jurcek, P.

    1998-01-01

    The through-diffusion and the modified breakthrough methods have been used for the determination of the effective (D e ) and apparent (D a ) diffusion coefficients for 85 Sr and 137 Cs in the compacted bentonite. Dry bulk density and the porosity of the dry bentonite together with the water content in the saturated bentonite have been measured as well. Distribution coefficients have been calculated from the results of the diffusion experiments and they have been compared with the values of the distribution coefficient determined by batch method. The sorption experiments with 99 Tc on bentonite have been carried out under various oxidizing conditions. The K d values have been determined using two different analytical methods -radiometry and polarography

  7. Sorption of antimony on human teeth

    International Nuclear Information System (INIS)

    Nofal, M.; Amin, H.; Alian, G.

    1997-01-01

    The study of the uptake of toxic elements on human teeth represents an interesting research area, as the fate of these elements when present in the human food is of health significance. Since antimony is one of the common toxic elements and since, the chemical behaviour of antimony is similar to that of arsenic, one of the most important toxic elements commonly encountered in cases of food poisoning, it has been decided to investigate its uptake on human teeth and on other restoration materials. The radioactive tracer technique was used to evaluate the concentration of antimony sorbed on teeth. This tracer was obtained by irradiation of antimony metal in the reactor, subsequent dissolution in concentrated sulphuric acid, evaporation to dryness and making the solution 6 M in Hydrochloric acid (1). Antimony prepared in this way is in the trivalent state (Sb III). Sorption was studied in water, tea, coffee, red tea and chicken soup. The highest sorption was achieved from water and chicken soup and least sorption was noticed in case of coffee. The results are presented in the form of the depletion of the radioactivity (A) of antimony with time in presence of a tooth in water and other drinks

  8. Lead sorption-desorption from organic residues.

    Science.gov (United States)

    Duarte Zaragoza, Victor M; Carrillo, Rogelio; Gutierrez Castorena, Carmen M

    2011-01-01

    Sorption and desorption are mechanisms involved in the reduction of metal mobility and bioavailability in organic materials. Metal release from substrates is controlled by desorption. The capacity of coffee husk and pulp residues, vermicompost and cow manure to adsorb Pb2+ was evaluated. The mechanisms involved in the sorption process were also studied. Organic materials retained high concentrations of lead (up to 36,000 mg L(-1)); however, the mechanisms of sorption varied according to the characteristics of each material: degree of decomposition, pH, cation exchange capacity and percentage of organic matter. Vermicompost and manure removed 98% of the Pb from solution. Lead precipitated in manure and vermicompost, forming lead oxide (PbO) and lead ferrite (PbFe4O7). Adsorption isotherms did not fit to the typical Freundlich and Langmuir equations. Not only specific and non-specific adsorption was observed, but also precipitation and coprecipitation. Lead desorption from vermicompost and cow manure was less than 2%. For remediation of Pb-polluted sites, the application of vermicompost and manure is recommended in places with alkaline soils because Pb precipitation can be induced, whereas coffee pulp residue is recommended for acidic soils where Pb is adsorbed.

  9. Batch experiments for assessing the sorption/desorption characteristics of 152Eu in systems of loose sediments and water containing humic acids

    International Nuclear Information System (INIS)

    Klotz, D.

    2001-01-01

    The 152 Eu distribution coefficients of the sorption and desorption of non-binding loose sediments of different grain sizes are investigated using a groundwater of tertiary lignite from Northern Germany which contains high concentrations of humic acids. The batch experiments were carried out with a ratio of 2.5cm 3 /g of solution volume to sediment mass, without mixing [de

  10. Mathematical Modeling of Moisture Sorption Isotherms and Determination of Isosteric Heats of Sorption of Ziziphus Leaves

    Directory of Open Access Journals (Sweden)

    Amel Saad

    2014-01-01

    Full Text Available Desorption and adsorption equilibrium moisture isotherms of Ziziphus spina-christi leaves were determined using the gravimetric-static method at 30, 40, and 50°C for water activity (aw ranging from 0.057 to 0.898. At a given aw, the results show that the moisture content decreases with increasing temperature. A hysteresis effect was observed. The experimental data of sorption were fitted by eight models (GAB, BET, Henderson-Thompson, modified-Chung Pfost, Halsey, Oswin, Peleg, and Adam and Shove. After evaluating the models according to several criteria, the Peleg and Oswin models were found to be the most suitable for describing the sorption curves. The net isosteric heats of desorption and adsorption of Ziziphus spina-christi leaves were calculated by applying the Clausius-Clapeyron equation to the sorption isotherms and an expression for predicting these thermodynamic properties was given.

  11. Measurement of distribution coefficients of U series radionuclides on soils under shallow land environment (2). pH dependence of distribution coefficients

    International Nuclear Information System (INIS)

    Sakamoto, Yoshiaki; Takebe, Shinichi; Ogawa, Hiromichi; Inagawa, Satoshi; Sasaki, Tomozou

    2001-01-01

    In order to study sorption behavior of U series radionuclides (Pb, Ra, Th, Ac, Pa and U) under aerated zone environment (loam-rain water system) and aquifer environment (sand-groundwater system) for safety assessment of U bearing waste, pH dependence of distribution coefficients of each element has been obtained. The pH dependence of distribution coefficients of Pb, Ra, Th, Ac and U was analyzed by model calculation based on aqueous speciation of each element and soil surface charge characteristics, which is composed of a cation exchange capacity and surface hydroxyl groups. From the model calculation, the sorption behavior of Pb, Ra, Th, Ac and U could be described by a combination of cation exchange reaction and surface-complexation model. (author)

  12. Development of a web-based sorption database (KAERI-SDB) and application to the safety assessment of a radioactive waste disposal

    International Nuclear Information System (INIS)

    Lee, Jae-Kwang; Baik, Min-Hoon; Choi, Jong-Won; Seo, Min-Seok

    2011-01-01

    Sorption plays a key role in a retardation of radionuclide migration in various geological environments. Hence sorption of radionuclides onto geological media is one of the important factors for the safety assessment of radioactive waste disposal. A web-based radionuclide sorption database program named KAERI-SDB has been developed to provide a database for the sorption of radionuclides onto geological media at various geochemical conditions. The KAERI-SDB is designed to determine the distribution coefficient (K d ) of a radionuclide and evaluate sorption properties by easily accessing an internet web-site ( (http://sdb.kaeri.re.kr)). The KAERI-SDB provides a useful output and search result as a scatter plot chart or an index chart. The KAEI-SDB was designed to show the search results in a statistical way by representing the mean K d value at 95% of confidence as a function of major geochemical indices. Several case studies were carried out to demonstrate the applicability of the KAERI-SDB and the result showed a successful applicability of the KAERI-SDB to various radionuclide sorption cases.

  13. Geochemical modelling of the sorption of tetravalent radioelements

    International Nuclear Information System (INIS)

    Bond, K.A.; Tweed, C.J.

    1991-05-01

    The results of an experimental study of the sorption of a range of tetravalent radioelements, plutonium (IV), tin (IV), thorium(IV) and uranium(IV), onto clay at pH8 and pH11 have been successfully simulated using a triple layer sorption model. The model has been incorporated into HARPHRQ, a geochemical program based on PHREEQE. The model has been parameterised using data for sorption onto ferric oxyhydroxide and goethite. The effects of hydroxycarboxylic acids on the sorption process have also been investigated experimentally. It was generally observed that in the presence of 2x10 -3 M gluconate, sorption was reduced by up two orders of magnitude. The model has satisfactorily simulated these lower sorptivities, through assuming competing sorption and complexation reactions. This work, therefore, further confirms the need to take account of such organic materials in safety assessment modelling. (author)

  14. Investigation of metal ions sorption of brown peat moss powder

    Science.gov (United States)

    Kelus, Nadezhda; Blokhina, Elena; Novikov, Dmitry; Novikova, Yaroslavna; Chuchalin, Vladimir

    2017-11-01

    For regularities research of sorptive extraction of heavy metal ions by cellulose and its derivates from aquatic solution of electrolytes it is necessary to find possible mechanism of sorption process and to choice a model describing this process. The present article investigates the regularities of aliovalent metals sorption on brown peat moss powder. The results show that sorption isotherm of Al3+ ions is described by Freundlich isotherm and sorption isotherms of Na+ i Ni2+ are described by Langmuir isotherm. To identify the mechanisms of brown peat moss powder sorption the IR-spectra of the initial brown peat moss powder samples and brown peat moss powder samples after Ni (II) sorption were studied. Metal ion binding mechanisms by brown peat moss powder points to ion exchange, physical adsorption, and complex formation with hydroxyl and carboxyl groups.

  15. suitability of murram for phosphorus sorption in constructed wetlands

    African Journals Online (AJOL)

    Mimi

    sorption isotherms, determination of Phosphorus sorption capacity of the substrates, determination of. Phosphorus sorption as the function of time and determination of effect of temperature on the ... (Na2O + K2O) % SiO2. %. P2O5. %. TiO2. %. LOI. %. 19.2. 1.3. 0.69. 5.13. 0.05. 6.7. 61.9. 0.04. 0.51. 4.4. As presented in ...

  16. Mechanism of cesium sorption on potassium titanium hexacyanoferrate

    International Nuclear Information System (INIS)

    Sun Yongxia; Xu Shiping; Song Chongli

    1998-01-01

    The mechanism of cesium sorption on potassium titanium hexacyanoferrate is described. The dependence of the sorption speed on temperature, particle granule size, and the stirring speed is studied. The results show that the sorption process is controlled by liquid film diffusion and particle diffusion. An exchange reaction occurs mainly between K + in the exchanger and Cs + in the solution, i.e. potassium titanium hexacyanoferrate, and Cs + of simulated high-level liquid waste

  17. A quantitative mechanistic description of Ni, Zn and Ca sorption on Na-montmorillonite. Part III: modelling

    International Nuclear Information System (INIS)

    Baeyens, B.; Bradbury, M.H.

    1995-07-01

    Titration and sorption measurements, carried out under a wide variety of conditions on Na-montmorillonite, were examined in terms of cation exchange and surface complexation mechanisms. A computer code called MINSORB was developed and used throughout this work. This code allowed the uptake of radionuclides by both mechanisms to be calculated simultaneously; also taking into account competitive reactions from other cations present. A stepwise iterative fitting/modelling procedure is described. For the case of Na-montmorillonite it is demonstrated that an electrostatic term in the surface complexation model is not required. A basic data set comprising of site capacities and protonation/deprotonation constants was defined, which was valid for all surface complexation sorption reactions. The main study was carried out with Ni, but impurity cations present in the system, particularly Zn, had to be examined in addition due to their competitive effects on Ni sorption. The surface complexation behaviour of Ni and Zn was investigated in detail to give intrinsic surface complexation constants on two of the =SOH type sites included in the model. The sorption of Mg, Ca and Mn is also considered, though in less detail, and estimated surface complexation constants for these nuclides are presented. Cation exchange was included in all of the calculations. Measured selectivity coefficients for Ni-Na, Zn-Na and Ca-Na exchange reactions are given. The model, with the derived parameters, allowed all the data from titration measurements through sorption edges to sorption isotherms to be calculated. (author) 31 figs., 9 tabs., refs

  18. A quantitative mechanistic description of Ni, Zn and Ca sorption on Na-Montmorillonite. Part III: Modelling

    International Nuclear Information System (INIS)

    Baeyens, B.; Bradbury, M.H.

    1995-07-01

    Titration and sorption measurements, carried out under a wide variety of conditions on Na-montmorillonite, were examined in terms of cation exchange and surface complexation mechanisms. A computer code called MINSORB was developed and used throughout this work. This code allowed the uptake of radionuclides by both mechanisms to be calculated simultaneously; also taking into account competitive reactions from other cations present. A stepwise iterative fitting/modelling procedure is described. For the case of Na-montmorillonite it is demonstrated that an electrostatic term in the surface complexation model is not required. A basic data set comprising of site capacities and protonation/deprotonation constants was defined, which was valid for all surface complexation sorption reactions. The main study was carried out with Ni, but impurity cations present in the system, particularly Zn, had to be examined in addition due to their competitive effects on Ni sorption. The surface complexation behaviour of Ni and Zn was investigated in detail to give intrinsic surface complexation constants on two of the ≡SOH type sites included in the model. The sorption of Mg, Ca and Mn is also considered, though in less detail, and estimated surface complexation constants for these nuclides are presented. Cation exchange was included in all of the calculations. Measured selectivity coefficients for Ni-Na, Zn-Na and Ca-Na exchange reactions are given. The model, with the derived parameters, allowed all the data from titration measurements through sorption edges to sorption isotherms to be calculated. (author) 31 figs., 9 tabs., refs

  19. Sorption of the organic cation metoprolol on silica gel from its aqueous solution considering the competition of inorganic cations.

    Science.gov (United States)

    Kutzner, Susann; Schaffer, Mario; Börnick, Hilmar; Licha, Tobias; Worch, Eckhard

    2014-05-01

    Systematic batch experiments with the organic monovalent cation metoprolol as sorbate and the synthetic material silica gel as sorbent were conducted with the aim of characterizing the sorption of organic cations onto charged surfaces. Sorption isotherms for metoprolol (>99% protonated in the tested pH of around 6) in competition with mono- and divalent inorganic cations (Na(+), NH4(+), Ca(2+), and Mg(2+)) were determined in order to assess their influence on cation exchange processes and to identify the role of further sorptive interactions. The obtained sorption isotherms could be described well by an exponential function (Freundlich isotherm model) with consistent exponents (about 0.8). In general, a decreasing sorption of metoprolol with increasing concentrations in inorganic cations was observed. Competing ions of the same valence showed similar effects. A significant sorption affinity of metoprolol with ion type dependent Freundlich coefficients KF,0.77 between 234.42 and 426.58 (L/kg)(0.77) could still be observed even at very high concentrations of competing inorganic cations. Additional column experiments confirm this behavior, which suggests the existence of further relevant interactions beside cation exchange. In subsequent batch experiments, the influence of mixtures with more than one competing ion and the effect of a reduced negative surface charge at a pH below the point of zero charge (pHPZC ≈ 2.5) were also investigated. Finally, the study demonstrates that cation exchange is the most relevant but not the sole mechanism for the sorption of metoprolol on silica gel. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. The implications of water extractable organic matter (WEOM) on the sorption of typical parent, alkyl and N/O/S-containing polycyclic aromatic hydrocarbons (PAHs) by microplastics.

    Science.gov (United States)

    Li, Ruilong; Tan, Huadong; Zhang, Linlin; Wang, Shaopeng; Wang, Yinghui; Yu, Kefu

    2018-07-30

    Microplastics sorption of persistent organic pollutants (POPs) was the core processes that cause negative effects to biota, and their influencing factors and related mechanisms are poorly understood. In this study, we explored the impacts of water extractable organic matter (WEOM), an important source of endogenous dissolved organic matter in mangrove sediment, on the sorption coefficients of typical parent, alkyl and N/O/S-containing polycyclic aromatic hydrocarbons (PAHs) by microplastics. The presence of L-WEOM (D) impeded the PAHs sorption as the coefficients (K f ) decreased to 10.17 (μg/kg)/(μg/L) n and to 8.39 (μg/kg)/(μg/L) n for fluorene (Flu) and 1-methyl-fluorene (1-M-Flu), respectively. The K f exhibited good linear relationships with the aliphaticity of L-WEOM (p  0.05). Under the presences of L-WEOM (D), (S) and (K), the lone pair electrons of N/O/S-containing PAHs was the dominant factor contributing to the obvious difference of the K f values from the other groups. Moreover, the largest impact of L-WEOM (D) on the Flu sorption was in the case of PVC microplastics, while almost no effect was in the case of PS microplastics. The findings of our work may be helpful in improving our understanding of the role of WEOM on the sorption of PAHs to microplastics in the field mangrove sediment. Copyright © 2018 Elsevier Inc. All rights reserved.

  1. Isotherms and isosteric heat of sorption of two varieties of Peruvian quinoa

    Directory of Open Access Journals (Sweden)

    Augusto Pumacahua-Ramos

    2016-01-01

    Full Text Available The isosteric heats of sorption of two varieties of quinoa (Chenopodium quinoaWilld. grain were determined by the static gravimetric method at four temperatures (40, 50, 60 and 70 °C andin relative humidity environments provided by six saturated salt solutions. Six mathematical equations were used to model the experimental data: GAB, Oswin, Henderson, Peleg, Smith and Halsey. The isosteric heat of sorption was determined using the parameters of the GAB model. All the equations were shown to be appropriate by the coefficients of determination (R2 and the mean absolute error (MA%E. The influence of temperature was observed because the adsorption of water by the grains was lower at highertemperatures. The equilibrium moisture contents for security of storage, for long periods of time at water activity lower than 0.65, were 12 -13%. The effect of temperature on the parameters of the GAB model was analysed using the exponential Arrhenius equation. The isosteric heats of sorption were determined by applying the Clausius-Clapeyron equation as a function of humidity. The isosteric heat at 5% moisture for grains of the Blanca de Juli variety was 3663 kJ/kg and for the Pasankalla variety it was 3393 kJ/kg. The experimental data for isosteric heat as a function of humidity were satisfactorily modelled using three mathematical equations.

  2. Immobilization of metal hexa-cyanoferrates in chitin beads for cesium sorption: synthesis and characterization

    International Nuclear Information System (INIS)

    Vincent, T.; Guibal, E.; Vincent, C.; Barre, Y.; Guari, Y.; Le Saout, G.

    2014-01-01

    Five metal-potassium hexacyanoferrate/chitin composites (based on Cu, Ni, Zn, Co or Fe co-metal) have been prepared and characterized, using SEM-EDX, TEM, X-ray diffraction and FT-IR, before being compared for Cs(I) and 137 Cs(I) sorption. The Zn-ion exchanger was characterized by a much larger crystal size of about 250 nm compared with a few tens of nm for other ion-exchangers. The ion exchangers are well distributed in the whole mass of the composite and they are fully accessible to Cs(I), as evidenced by Cs(I) distribution after metal sorption. Uptake kinetics can be modeled using both the pseudo-second order rate equation and the Crank equation (resistance to intra-particle diffusion coefficient). Sorption isotherms showed substantial differences in the sorbents that can be ranked as Cu ≥ Ni ≥ Zn ≥ Co ≥ Fe. However, based on 137 Cs K d values, the sorbents can be ranked as Co≥≥Fe≥≥Cu≥≥Ni≥Zn. Taking into account the cost and toxicity of metals (both in terms of manufacturing and potential metal release) a Prussian Blue based sorbent (i.e., iron-potassium hexacyanoferrate/chitin composite) sounds to be a good composite for Cs(I) recovery from radionuclide-containing effluents. (authors)

  3. Soil sorption of two nitramines derived from amine-based CO2 capture.

    Science.gov (United States)

    Gundersen, Cathrine Brecke; Breedveld, Gijs D; Foseid, Lena; Vogt, Rolf D

    2017-06-21

    Nitramines are potentially carcinogens that form from the amines used in post-combustion CO 2 capture (PCCC). The soil sorption characteristics of monoethanol (MEA)- and dimethyl (DMA)-nitramines have been assessed using a batch experimental setup, and defined indirectly by measuring loss of nitramine (LC-MS/MS) from the aqueous phase (0.01 M CaCl 2 and 0.1% NaN 3 ) after equilibrium had been established with the soil (24 h). Nitramine soil sorption was found to be strongly dependent on the content of organic matter in the soil (r 2 = 0.72 and 0.95, p Soil sorption of MEA-nitramine was further influenced by the quality of the organic matter (Abs 254 nm , r 2 = 0.93, p soil organic matter. Estimated organic carbon normalized soil-water distribution coefficients (K OC ) are relatively low, and within the same range as for simple amines. Nevertheless, considering the high content of organic matter commonly found in the top layer of a forest soil, this is where most of the nitramines will be retained. Presented data can be used to estimate final concentrations of nitramines in the environment following emissions from amine-based PCCC plants.

  4. The sorption of metal ions on nanoscale zero-valent iron

    Directory of Open Access Journals (Sweden)

    Suponik Tomasz

    2017-01-01

    Full Text Available The injection of the colloidal suspensions of nano-iron (nZVI into an aquifer is a novel method of removing metal ions from acidic water. In the batch tests, the equilibrium study of the sorption of metal ions, Cu(II and Zn(II, on Green Tea nanoscale Zero-Valent Ion (GT-nZVI was carried out. The sorption of metal ions on this reactive material was described using the Langmuir, Freundlich and Sips models. This last model described in a better way the sorption equilibrium in the tested range of concentrations and temperature. The value of determination coefficient (R2 for the Sips model, for copper and zinc, was 0.9735 to 0.9995, respectively. GT-nZVI has very good properties in removing Cu(II and Zn(II from acidic water. The high values of qmaxS, the maximum adsorption capacity in the Sips model, amounting to 348.0 and 267.3 mg/g for Cu(II and Zn(II, indicate the high adsorption capacity of GT-nZVI. The analyzed metals have good or very good affinity with GT-nZVI.

  5. Sorption and mobility of 14C-fenamiphos in Brazilian soils.

    Science.gov (United States)

    Cáceres, Tanya; Venkateswarlu, Kadiyala

    2018-02-02

    Although fenamiphos is widely used as an insecticide and nematicide in bowling greens and agriculture, information on its sorption in tropical soils is limited. In this study, mobility, sorption, and desorption dynamics of 14 C-fenamiphos in three contrasting Brazilian soils were examined both in batch and column experiments. Fenamiphos sorption coefficients (K d ) were 2.33, 3.86, and 3.9 L kg -1 for the three soils tested. The insecticide exhibited linear adsorption isotherms in all the three soils, and desorption was in a range of 30-40% during a 72-h period. With its low mobility, fenamiphos did not percolate through the soil profile even after 48 h. However, there is a risk of leaching to water bodies due to runoff because of its high solubility in water. In view of the fact that fenamiphos and its oxidation products are highly toxic to aquatic invertebrates and could affect the soil microbial activities even at low concentrations, the present information is of great importance in risk assessment of fenamiphos in the environment.

  6. Sorption and desorption of cesium and strontium on TA-2 and TA-41 soils and sediments

    International Nuclear Information System (INIS)

    Kung, K. Stephen; Li, Benjamin W.; Longmire, P.A.; Fowler, M.M.

    1996-04-01

    Current environmental monitoring has detected radioactive contaminants in alluvial groundwater, soils, and sediments in the TA-2 and TA-41 areas along the north central edge of Los Alamos National Laboratory. Because of this contamination, this study was initiated. The objective of this study is to quantify the sorptivity of cesium and strontium onto TA-2 and TA-41 site specific soil samples under a controlled environment in the laboratory. The purposes of this work are to determine cesium and strontium sorption coefficient for these sit specific soils and to evaluate the potential transport of cesium and strontium. Based on this information, a risk assessment and remediation strategy can be developed

  7. Sorption of curium by silica colloids: Effect of humic acid

    International Nuclear Information System (INIS)

    Kar, Aishwarya Soumitra; Kumar, Sumit; Tomar, B.S.; Manchanda, V.K.

    2011-01-01

    Sorption of curium by silica colloids has been studied as a function of pH and ionic strength using 244 Cm as a tracer. The sorption was found to increase with increasing pH and reach a saturation value of ∼95% at pH beyond 5.3. The effect of humic acid on the sorption of 244 Cm onto silica was studied by changing the order of addition of the metal ion and humic acid. In general, in the presence of humic acid (2 mg/L), the sorption increased at lower pH (<5) while it decreased in the pH range 6.5-8 and above pH 8, the sorption was found to increase again. As curium forms strong complex with humic acid, its presence results in the enhancement of curium sorption at lower pH. At higher pH the humic acid present in the solution competes with the surface sites for curium thus decreasing the sorption. The decrease in the Cm sorption in presence of humic acid was found to be less when humic acid was added after the addition of curium. Linear additive model qualitatively reproduced the profile of the Cm(III) sorption by silica in presence of humic acid at least in the lower pH region, however it failed to yield quantitative agreement with the experimental results. The results of the present study evidenced the incorporation of Cm into the silica matrix.

  8. Development of Web-based Software for Sorption Database

    International Nuclear Information System (INIS)

    Han, Byoung Sub; Lee, Jae Min; Seo, Min Seok; Kim, Dong Keon

    2009-08-01

    Sorption studies of radionuclides are important parts of research on radioactive waste disposal which is commonly faced in most countries where nuclear programs (power production, a variety of peaceful applications, and research) are implemented. The Sorption Database (DB) plays a very important role in the safety assessment of the radioactive waste disposal. The Sorption DB which is opened externally can be used as reference material of establishing a national policy by improving and changing the pre-developed Sorption program to be web-based. From the industrial point of view, if the Sorption DB is opened to the outside, the safety-related confidence can be achieved for nuclear industry. As the information of Sorption DB is opened, not only credibility can be provided to the administration, local governments and nearby residents, but also input of the collected information can be achieved by online. In addition, the reference material and external awareness/reliability about the domestic level of the Sorption DB management system and the current state can be achieved internationally. In order to provide the information of Sorption DB to users in more efficient way, the analysis and complement of management and search capability for the existing Sorption DB program have been performed and web-based management system has been built to provide services to users. In addition, by applying statistical techniques, it has been designed and implemented to display the accuracy and error of the information

  9. Determining Sorption Rate by a Continuous Gravimetric Method

    National Research Council Canada - National Science Library

    Hall, Monicia R; Procell, Lawrence R; Bartram, Philip W; Shuely, Wendel J

    2003-01-01

    ... were automatically recorded in an Excel file while CARC coupons were submerged in solvent. Initial sorption rates were determined for butyl acetate, butyl ether, cyclohexane and propylene carbonate...

  10. The sorption of polonium, actinium and protactinium onto geological materials

    International Nuclear Information System (INIS)

    Baston, G.M.N.; Berry, J.A.; Brownsword, M.; Heath, T.G.; Ilett, D.J.; McCrohon, R.; Tweed, C.J.; Yui, M.

    1999-01-01

    This paper describes a combined experimental and modeling program of generic sorption studies to increase confidence in the performance assessment for a potential high-level radioactive waste repository in Japan. The sorption of polonium, actinium and protactinium onto geological materials has been investigated. Sorption of these radioelements onto bentonite, tuff and granodiorite from equilibrated de-ionized water was studied under reducing conditions at room temperature. In addition, the sorption of actinium and protactinium was investigated at 60 C. Thermodynamic chemical modeling was carried out to aid interpretation of the results

  11. The sorption of polonium, actinium and protactinium onto geological materials

    Energy Technology Data Exchange (ETDEWEB)

    Baston, G.M.N.; Berry, J.A.; Brownsword, M.; Heath, T.G.; Ilett, D.J.; McCrohon, R.; Tweed, C.J.; Yui, M.

    1999-07-01

    This paper describes a combined experimental and modeling program of generic sorption studies to increase confidence in the performance assessment for a potential high-level radioactive waste repository in Japan. The sorption of polonium, actinium and protactinium onto geological materials has been investigated. Sorption of these radioelements onto bentonite, tuff and granodiorite from equilibrated de-ionized water was studied under reducing conditions at room temperature. In addition, the sorption of actinium and protactinium was investigated at 60 C. Thermodynamic chemical modeling was carried out to aid interpretation of the results.

  12. Radionuclide sorption in Yucca Mountain tuffs with J-13 well water: Neptunium, uranium, and plutonium. Yucca Mountain site characterization program milestone 3338

    International Nuclear Information System (INIS)

    Triay, I.R.; Cotter, C.R.; Kraus, S.M.; Huddleston, M.H.

    1996-08-01

    We studied the retardation of actinides (neptunium, uranium, and plutonium) by sorption as a function of radionuclide concentration in water from Well J-13 and of tuffs from Yucca Mountain. Three major tuff types were examined: devitrified, vitric, and zeolitic. To identify the sorbing minerals in the tuffs, we conducted batch sorption experiments with pure mineral separates. These experiments were performed with water from Well J-13 (a sodium bicarbonate groundwater) under oxidizing conditions in the pH range from 7 to 8.5. The results indicate that all actinides studied sorb strongly to synthetic hematite and also that Np(V) and U(VI) do not sorb appreciably to devitrified or vitric tuffs, albite, or quartz. The sorption of neptunium onto clinoptilolite-rich tuffs and pure clinoptilolite can be fitted with a sorption distribution coefficient in the concentration range from 1 X 10 -7 to 3 X 10 -5 M. The sorption of uranium onto clinoptilolite-rich tuffs and pure clinoptilolite is not linear in the concentration range from 8 X 10 -8 to 1 X 10 -4 M, and it can be fitted with nonlinear isotherm models (such as the Langmuir or the Freundlich Isotherms). The sorption of neptunium and uranium onto clinoptilolite in J-13 well water increases with decreasing pH in the range from 7 to 8.5. The sorption of plutonium (initially in the Pu(V) oxidation state) onto tuffs and pure mineral separates in J-13 well water at pH 7 is significant. Plutonium sorption decreases as a function of tuff type in the order: zeolitic > vitric > devitrified; and as a function of mineralogy in the order: hematite > clinoptilolite > albite > quartz

  13. Acquisition of sorption isotherms for modified woods by the use of dynamic vapour sorption instrumentation. Principles and Practice

    DEFF Research Database (Denmark)

    Engelund, Emil Tang; Klamer, Morten; Venås, Thomas Mark

    2010-01-01

    The complex wood-water relationship has been the topic of numerous studies. Sorption isotherms – in particular – have been derived for hundreds of wood species, their sap- and heartwood sections as well as for decayed, engineered and modified wood materials. However, the traditional methods...... for obtaining sorption isotherms are very time consuming. With new dynamic vapour sorption (DVS) instrumentation, the acquisition of data for constructing sorption isotherms is suddenly dramatically lowered. Where the traditional methods often required months, data can now be obtained in a matter of days...... depending on the number of data points required. The fast data acquisition makes DVS a useful tool in studying the sorption properties of wood, and especially in studying the effect of different modification treatments on these properties. This study includes an investigation of the sorption properties...

  14. A renewal of the JNC-sorption database (JNC-SDB) addition of literature data published from 1998 to 2003

    International Nuclear Information System (INIS)

    Suyama, Tadahiro; Sasamoto, Hiroshi

    2004-02-01

    The sorption database was developed by Japan Nuclear Cycle Development Institute for 'H12:Project to establish the scientific and technical basis for HLW disposal in Japan' in 1999. The database includes distribution coefficient of important radionuclides for estimating a retardation capacity on engineered barrier and natural barrier. At this time, we collected the newest sorption data (distribution coefficient) using UNIS (International Nuclear Information System) in order to extend and renew the database. The up dated database includes the published data from 1998 to 2003. When the JNC-SDB was developed for the H12 report, it was not completed to include some literature data used in OECD/NEA sorption database. At this time, we collected the missing literatures and added the data to the JNC-SDB. In the up dated JNC-SDB, important elements on performance assessment such as Am, Cm, Cs, Np, Pb, Pu, Se, Tc and U, additional elements such as Ag, Ba, Co, Eu, Fe, I, Mn, Mo, Sr and Zn were increased. It was increased 1,236 data of 19 elements. As the result, the frequency of distribution coefficient for some elements clearly shows increased data. And also, input miss in the previous JNC-SDB developed in 1999 were corrected at this time. (author)

  15. Estimation of biotransformation and sorption of emerging organic compounds (EOCs) during artificial recharge through a reactive barrier.

    Science.gov (United States)

    Valhondo, C.; Martinez-Landa, L.; Carrera, J.; Hidalgo, J. J.; Ayora, C.

    2016-12-01

    The reuse of lesser quality water such as effluents from wastewater treatment plants or effluent-receiving water bodies has been promoted due to the water shortages affecting many regions of the world. Artificial recharge through infiltration basins is known to improve several water quality parameters including the attenuation of emerging organic compounds (EOCs). Many of these contaminants exhibit redox dependent biotransformation because the redox state is one of the factors controlling microbial community development. Together with biotransformation, sorption also affects the behavior of EOCs in their passage through the soil. We studied EOCs attenuation in an infiltration system is located in Sant Vicenç dells Horts on the Llobregat delta (Barcelona, Spain), where the local water agency has an artificial recharge pilot project . The Llobregat river water used for the artificial recharge is affected by treatment plant effluents which contain EOCs. A reactive barrier consisting of vegetable compost, clay, and iron oxide was installed in the bottom of the infiltration basin to enhance biotransformation and sorption of EOCs. The barrier releases dissolved organic carbon, which favors the development of a broad range of redox environments, and supplies neutral, cationic, and anionic surfaces to favor sorption of different types of contaminants. Results were excellent, but quantitative evaluation of the EOCs attenuation requires knowledge of the residence time distribution of infiltrated water. A tracer test was performed by adding tracers to the infiltration water and interpreting the breakthrough curves at diverse monitoring points with a 2D multilayer numerical model. The calibrated model quantify degradation, as a first order law, and sorption through a linear distribution coefficient for ten selected EOCs. Results indicate higher degradation rates and sorption coefficients in the reactive barrier than in the rest of the aquifer for nine and eight of the ten

  16. Attenuation coefficients of soils

    International Nuclear Information System (INIS)

    Martini, E.; Naziry, M.J.

    1989-01-01

    As a prerequisite to the interpretation of gamma-spectrometric in situ measurements of activity concentrations of soil radionuclides the attenuation of 60 to 1332 keV gamma radiation by soil samples varying in water content and density has been investigated. A useful empirical equation could be set up to describe the dependence of the mass attenuation coefficient upon photon energy for soil with a mean water content of 10%, with the results comparing well with data in the literature. The mean density of soil in the GDR was estimated at 1.6 g/cm 3 . This value was used to derive the linear attenuation coefficients, their range of variation being 10%. 7 figs., 5 tabs. (author)

  17. Sorption interactions of organic compounds with soils affected by agricultural olive mill wastewater.

    Science.gov (United States)

    Keren, Yonatan; Borisover, Mikhail; Bukhanovsky, Nadezhda

    2015-11-01

    The organic compound-soil interactions may be strongly influenced by changes in soil organic matter (OM) which affects the environmental fate of multiple organic pollutants. The soil OM changes may be caused by land disposal of various OM-containing wastes. One unique type of OM-rich waste is olive mill-related wastewater (OMW) characterized by high levels of OM, the presence of fatty aliphatics and polyphenolic aromatics. The systematic data on effects of the land-applied OMW on organic compound-soil interactions is lacking. Therefore, aqueous sorption of simazine and diuron, two herbicides, was examined in batch experiments onto three soils, including untreated and OMW-affected samples. Typically, the organic compound-soil interactions increased following the prior land application of OMW. This increase is associated with the changes in sorption mechanisms and cannot be attributed solely to the increase in soil organic carbon content. A novel observation is that the OMW application changes the soil-sorbent matrix in such a way that the solute uptake may become cooperative or the existing ability of a soil sorbent to cooperatively sorb organic molecules from water may become characterized by a larger affinity. The remarkable finding of this study was that in some cases a cooperative uptake of organic molecules by soils makes itself evident in distinct sigmoidal sorption isotherms rarely observed in soil sorption of non-ionized organic compounds; the cooperative herbicide-soil interactions may be characterized by the Hill model coefficients. However, no single trend was found for the effect of applied OMW on the mechanisms of organic compound-soil interactions. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. Sorption behavior of cobalt on manganese dioxide, smectite and their mixture

    International Nuclear Information System (INIS)

    Ohnuki, T.; Kozai, N.

    1995-01-01

    The sorption behavior of cobalt on manganese dioxide, the clay mineral smectite and mixtures of the two was studied by batch type sorption/desorption experiments at neutral pH. Sorption behavior was examined by sequential extraction, in which the sorbents were contacted first with a 1 M CH 3 COONH 4 solution and then with a hydroxylamine solution (NH 2 OH of 1 M with 25 weight % CH 3 COOH). More than 70% of the sorbed cobalt was desorbed from smectite with a 1 M CH 3 COONH 4 solution: about 15% of the cobalt remained on the smectite after treatment with the hydroxylamine solution. Less than 1% of the remaining cobalt was desorbed from manganese dioxide with a 1 M CH 3 COONH 4 solution; with the hydroxylamine solution, all was desorbed. In mixtures of MnO 2 and smectite that were formulated to sorb equal amounts of cobalt regardless of the MnO 2 /smectite ratio in the mixture, less than 5% of the sorbed cobalt was desorbed by treatment with 1 M CH 3 COONH 4 . The fraction of the cobalt desorbed by treatment with the hydroxylamine solution increased with increased MnO 2 in the mixtures. The fraction of the cobalt sorbed on MnO 2 in the mixture was estimated from the desorption experiments. The results showed that higher fractions were sorbed onto MnO 2 than were estimated by the weighted averages of distribution coefficients for MnO 2 and smectite. Therefore, in minerals of the mixture, manganese dioxide is a more important component than smectite for the sorption of cobalt. (orig.)

  19. Sorption isotherms for oat flakes (Avena sativa L.

    Directory of Open Access Journals (Sweden)

    José Edgar Zapata M.

    2014-04-01

    Full Text Available Moisture sorption isotherms of oat flakes were determined at temperatures of 5, 25 and 37°C, using a gravimetric technique in an a w range of between 0.107 and 0.855. These curves were modeled using six equations commonly applied in food. The quality of the fit was assessed with the regression coefficient (r² and the mean relative percentage error (MRPE. The best fit were obtained with the Caurie model with r² of 0.996, 0.901 and 0.870, and MRPE of 7.190, 17.878 and 16.206, at 5, 25 and 37°C, respectively. The equilibrium moisture presented a dependence on temperature in the studied a w range, as did the security moisture (X S. These results suggest that the recommended storage conditions of oat flakes include: a relative air humidity of 50% between 5 and 25°C and of 38% up to 37°C.

  20. 3.3. Sorption activity of cross-linked polymers of ethynyl-piperidol

    International Nuclear Information System (INIS)

    Khalikov, D.Kh.

    2012-01-01

    The sorption activity of cross-linked polymers of ethynyl-piperidol was studied. The bilirubin sorption was studied as well. The kinetic of bilirubin sorption and human serum albumin at their joint presence in hydrogel solutions was defined. Bilirubin sorption and change of albumin composition was considered. The sorption of middle molecular peptides was considered as well. The sorption of endogenous toxin by means of ethynyl-piperidol polymers was done.

  1. Sorption of nitrate onto amine-crosslinked wheat straw: characteristics, column sorption and desorption properties.

    Science.gov (United States)

    Xing, Xu; Gao, Bao-Yu; Zhong, Qian-Qian; Yue, Qin-Yan; Li, Qian

    2011-02-15

    The nitrate removal process was evaluated using a fixed-bed column packed with amine-crosslinked wheat straw (AC-WS). Column sorption and desorption characteristics of nitrate were studied extensively. Solid-state (13)C NMR and zeta potential analysis validated the existence of crosslinked amine groups in AC-WS. Raman shift of the nitrate peaks suggested the electrostatic attraction between the adsorbed ions and positively charged amine sites. The column sorption capacity (q(ed)) of the AC-WS for nitrate was 87.27 mg g(-1) in comparison with the raw WS of 0.57 mg g(-1). Nitrate sorption in column was affected by bed height, influent nitrate concentration, flow rate and pH, and of all these, influent pH demonstrated an essential effect on the performance of the column. In addition, desorption and dynamic elution tests were repeated for several cycles, with high desorption rate and slight losses in its initial column sorption capacity. Copyright © 2010 Elsevier B.V. All rights reserved.

  2. Humidity sorption on natural building stone

    Science.gov (United States)

    Franzen, C.; Mirwald, P.

    2003-04-01

    processes, physical, chemical or biological, depend on the presence of water. Like most porous materials building stone respond on humidity by water uptake. The sorption isotherm represents the equilibrium moisture, specific for each material. The determination of the isotherm for stone of low and small porosity like marble is difficult. With the help of a newly developed water sorption analysis chamber [2], which allows the simultaneous measurement of 11 samples, good results on stone/rock samples have been obtained. Even at marble species with pore volumes lower than 0.4 % isotherms are measured. This analytical method offers new insights in the pore behaviour of low porosity materials. The advantages of this technique which supplements other techniques (e.g. BET, Hg-porosimetry) are: i) the testing agent is identical to the weathering agent, water; ii) the atmospheric parameters at the measurement reflect the natural conditions - thus no changes to the material properties have to be considered; iii) due to the small diameter of the water molecule (~0.28 nm), smaller pores are reached than e.g. with N2 (~0.31 nm). Sorption isotherms of sandstone (Baumberg, Obernkirchen, Groeden), granite (Brixen), and marble (Sterzing, Laas) are presented. Particular as to marbles the resolution is considerably higher. A previously observed negative hysteresis [3] seems an effect due to limited data resolution. [1] Snethlage, R. (1984) Steinkonservierung, Bayer. LA Denkmalpflege, Ah. 22, 203 S. [2] Griesser, U.J., Dillenz, J. (2002) Neuartiges, vollautomatisches Feuchtesorptionsprüfgerät mit hohem Probendurchsatz, Feuchtetag 2002, Weimar, 85-93. [3] Fimmel, R. (1996) Verwitterungsverhalten der alpinen Marmore von Laas und Sterzing, Diss. Univ. Ibk, 116 S.

  3. EXAFS study of plutonium sorption onto kaolinite

    International Nuclear Information System (INIS)

    Reich, T.Y.; Banik, L.; Buda, R.A.; Amayri, S.; Drebert, J.; Kratz, J.V.; Trautmann, N.; Reich, T.; Ageev, A.L.; Korshunov, M.E.

    2007-01-01

    The uptake mechanism of plutonium by kaolinite was investigated by applying X-ray absorption spectroscopy to batch sorption samples (total Pu concentrations 1 and 10 μM; 4 g kaolinite/L in 0.1 M NaClO 4 ; 1 ≤ pH ≤ 9; presence and absence of ambient CO 2 ). For XAFS measurements, one sample was prepared from a Pu(III) solution at pH 6 under argon atmosphere. Three samples were obtained by sorption of Pu(IV) at pH I, 4, and 9 in an air-equilibrated system. The Pu L III -edge XANES spectra indicated that in all samples, including the Pu(III) sample, plutonium is sorbed at the kaolinite surface as Pu(IV). The Pu L III -edge k 3 -weighted EXAFS spectra showed eight oxygen atoms at an average Pu-O distance of 2.3 angstrom. Two Pu atoms were detected at ∼ 3.7 angstrom in all spectra, indicating the formation of polynuclear Pu(IV) species at the kaolinite surface. For the sample prepared from Pu(III) solution, an additional Pu-O shell at 3.2 angstrom was observed. The spectra of samples prepared from Pu(IV) included a Pu-Al/Si co-ordination shell at approximately 3.6 angstrom, indicating formation of inner-sphere sorption complexes. The structural models used in the least-squares fits were confirmed by an alternative EXAFS data analysis approach based on a modified Tikhonov regularization method. (authors)

  4. Influence of concentration and hydrodynamic factors in sorption of iodine by anion-exchangers of the mass-transfer rate

    International Nuclear Information System (INIS)

    Sokolov, V.V.; Smirnov, N.N.

    1982-01-01

    An investigation of the joint influence of hydrodynamic and concentration factors in sorption of iodine by AV-17-8 and anion exchange resins on the mass-transfer coefficient is the subject of this report. The method of central composite rotatable experimental design was used for quantitative assessment and derivation of the appropriate equations. The investigation yielded the necessary regression equations satisfactorily describing the influence of all the factors in the mass-transfer coefficient. the optimal mass-transfer conditions were determined. On the basis of the values obtained, recommendations are made on the optimal hydrodynamic conditions of operation of equipment with pneumatic circulation of the ion-exchanger

  5. Sorption of pesticides to aquifer minerals

    DEFF Research Database (Denmark)

    Clausen, Liselotte; Fabricius, Ida Lykke

    2000-01-01

    This paper summarizes results from a work were the sorption of five pesticides on seven minerals were studied in order to quantify the adsorption to different mineral surfaces. Investigated mineral phases are: quartz, calcite, kaolinite, a-alumina, and three iron oxides (2-line ferrihydrite......, goethite, lepidocrocite). Selected pesticides are: atrazine, isoproturon, mecoprop, 2,4-D, and bentazone. The results demonstrate that pesticides adsorb to pure mineral surfaces. However, the size of the adsorption depends on the type of pesticide and the type of mineral....

  6. Tritium sorption by cement and subsequent release

    International Nuclear Information System (INIS)

    Ono, F.; Tanaka, S.; Yamawaki, M.

    1994-01-01

    In a fusion reactor or tritium handling facilities, contamination of concrete by tritium and subsequent release from it to the reactor or experimental rooms is a matter of problem for safety control of tritium and management of operational environment. In order to evaluate these tritium behavior, interaction of tritiated water with concrete or cement should be clarified. In the present study, HTO sorption and subsequent release from cement were studied by combining various experimental methods. From the basic studies on tritium-cement interactions, it has become possible to evaluate tritium uptake by cement or concrete and subsequent tritium release behavior as well as tritium removing methods from them

  7. Thermodynamics of imidacloprid sorption in Croatian soils

    Science.gov (United States)

    Milin, Čedomila; Broznic, Dalibor

    2015-04-01

    Neonicotinoids are increasingly replacing the organophosphate and methylcarbamate acetylcholinesterase inhibitors which are losing their effectiveness because of selection for resistant pest populations. Imidacloprid is the most important neonicotinoid with low soil persistence, high insecticidal potency and relatively low mammalian toxicity. In Croatia, imidacloprid is most commonly used in olive growing areas, including Istria and Kvarner islands, as an effective means of olive fruit fly infestation control. Sorption-desorption behavior of imidacloprid in six soils collected from five coastal regions in Croatia at 20, 30 and 40°C was investigated using batch equilibrium technique. Isothermal data were applied to Freundlich, Langmuir and Temkin equation, and the thermodynamic parameters ΔH°, ΔG°, ΔS° were calculated. The sorption isotherm curves were of non-linear and may be classified as L-type suggesting a relatively high sorption capacity for imidacloprid. Our results showed that the KFsor values decreased for all the tested soils as the temperature increases, indicating that the temperature strongly influence the sorption. Values of ΔG° were negative (-4.65 to -2.00 kJ/mol) indicating that at all experimental temperatures the interactions of imidacloprid with soils were spontaneous process. The negative and small ΔH° values (-19.79 to -8.89 kJ/mol) were in the range of weak forces, such as H-bonds, consistent with interactions and par¬titioning of the imidacloprid molecules into soil organic matter. The ΔS° values followed the range of -57.12 to -14.51 J/molK, suggesting that imidacloprid molecules lose entropy during transition from the solution phase to soil surface. It was found that imidacloprid desorption from soil was concentration and temperature dependent, i.e. at lower imidacloprid concentrations and temperature, lower desorption percentage occurred. Desorption studies revealed that hysteretic behavior under different temperature

  8. Sorption of radiostrontium from liquid metallic rubidium

    International Nuclear Information System (INIS)

    Zhujkov, B.L.; Kokhnyuk, V.M.; Vincent, J.S.

    2008-01-01

    One studied the radiostrontium (in particular, 82 Sr) sorption from the liquid metallic Rb in various inorganic sorbents (both metals and oxides). One studied the temperature dependence and the dynamics of the adsorption and put forward an interpretation of the observed mechanisms. The elaborated approach enables to extract 82 Sr efficiently from the Rb targets upon their irradiation by the accelerated protons. One studies various procedures and the applicability of the process to ensure elaboration of a new highly efficient process to produce 82 Sr, in particular, with the targets of the circulating Rb [ru

  9. The Truth About Ballistic Coefficients

    OpenAIRE

    Courtney, Michael; Courtney, Amy

    2007-01-01

    The ballistic coefficient of a bullet describes how it slows in flight due to air resistance. This article presents experimental determinations of ballistic coefficients showing that the majority of bullets tested have their previously published ballistic coefficients exaggerated from 5-25% by the bullet manufacturers. These exaggerated ballistic coefficients lead to inaccurate predictions of long range bullet drop, retained energy and wind drift.

  10. The interaction of sorbing and non-sorbing tracers with different Aespoe rock types. Sorption and diffusion experiments in the laboratory scale

    Energy Technology Data Exchange (ETDEWEB)

    Byegaard, J.; Johansson, Henrik; Skaalberg, M. [Chalmers Univ. of Technology, Goeteborg (Sweden). Dept. of Nuclear Chemistry; Tullborg, E.L. [Terralogica AB, Graabo (Sweden)

    1998-11-01

    Laboratory experiments studying the sorption and diffusivity of different tracers in Aespoe Hard Rock Laboratory (Aespoe HRL) site specific conditions have been performed. The experiments were conducted by applying both the batch sorption and the through diffusion technique. The investigation was focused on slightly sorbing tracers, i e, alkaline metals (Na{sup +}, Rb{sup +} and Cs{sup +}) and alkaline earth metals (Ca{sup 2+}, Sr{sup 2+} and Ba{sup 2+}), but some presumed non-sorbing species have also been included. The dominating generic rock material from Aespoe HRL, Aespoe-diorite and fine-grained granite, were used as well as some altered wall rock and mylonite from the Feature A fracture, the fracture where in situ migration studies have been performed. Synthetic groundwater was used; similar to the high saline groundwater found at the 350m level at Aespoe HRL and at the Feature A site. The results of batch experiments show that the sorption of the tracers increase in the order Nasorption coefficient of Na{sup +} in the order of (4-30)x10{sup -6} m{sup 3}/kg and for Cs{sup +} in the range of (I-400)x10{sup -3} m{sup 3}/kg. The variations in sorption coefficients are due to differences in the composition of the geological material, contact time and particle size. Sorption is generally stronger for the Aespoe-diorite than for the fine-grained granite which is explained by the much higher concentration of biotite in Aespoe diorite than in fine-grained granite. In the altered material the biotite has been transformed to chlorite and a lower sorptivity is shown for those material compared to the fresh diorite and granite, respectively. Attempts to explain the sorption and desorption results to a surface sorption - diffusion model are presented. The diffusion results show that the tracers were retarded in the same order as was expected from the measured batch sorption coefficients. Furthermore, the largest size fraction was the most

  11. Sorption of Triangular Silver Nanoplates on Polyurethane Foam

    Science.gov (United States)

    Furletov, A. A.; Apyari, V. V.; Garshev, A. V.; Volkov, P. A.; Tolmacheva, V. V.; Dmitrienko, S. G.

    2018-02-01

    The sorption of triangular silver nanoplates on polyurethane foam is investigated as a procedure for creating a nanocomposite sensing material for subsequent use in optical means of chemical analysis. Triangular silver nanoplates are synthesized and characterized, and a simple sorption technique for the formation of a composite material based on these nanoplates is proposed.

  12. Kinetics and reversibility of micropollutant sorption in sludge.

    Science.gov (United States)

    Barret, Maialen; Carrère, Hélène; Patau, Mathieu; Patureau, Dominique

    2011-10-01

    The fate of micropollutants throughout wastewater treatment systems is highly dependent on their sorption interactions with sludge matter. In this study, both the sorption and desorption kinetics of polycyclic aromatic hydrocarbons (PAHs) in activated sludge were shown to be very rapid in comparison to biodegradation kinetics. It was concluded that PAH transfer does not limit their biodegradation and that their fate is governed by the sorption/desorption equilibrium state. The effect of contact time between sludge and PAHs was also investigated. It was shown that aging did not influence the sorption/desorption equilibrium although PAH losses during aging suggest that sequestration phenomena had occurred. This implies that for PAH sorption assessment within treatment processes there is no need to include a contact time dimension. As a consequence, thanks to an innovative approach taking into account sorption equilibria and sequestration, this work has demonstrated that studies in the literature which, in main, deal with micropollutant sorption in sewage sludge with only a short contact time can be extrapolated to real systems in which sorption, desorption and aging occur.

  13. CO2 sorption of a ceramic separation membrane

    NARCIS (Netherlands)

    Wormeester, Herbert; Benes, Nieck Edwin; Spijksma, G.I.; Verweij, H.; Poelsema, Bene

    2004-01-01

    The ellipsometric characterization of the CO2 sorption of a silica membrane provides a fast and accurate technique for the characterization of maximum sorption and the heat of adsorption. Both parameters are evaluated for the 73 nm thick silica layer as well as the 1650 nm thick supporting γ-layer.

  14. Status report on SIRS: sorption information retrieval system

    International Nuclear Information System (INIS)

    Hostetler, D.D.; Serne, R.J.; Baldwin, A.J.; Petrie, G.M.

    1980-11-01

    Two major uses were identified for the Sorption Information Retrieval System: (1) to aid geochemists in the elucidation of sorption mechanisms; and (2) to aid safety assessment modelers in selection of Kds for any given scenerio. Other benefits such as providing an auditable vehicle for the Kd selection were also discussed

  15. Effect of humic acid (HA) on sulfonamide sorption by biochars

    International Nuclear Information System (INIS)

    Lian, Fei; Sun, Binbin; Chen, Xi; Zhu, Lingyan; Liu, Zhongqi; Xing, Baoshan

    2015-01-01

    Effect of quantity and fractionation of loaded humic acid (HA) on biochar sorption for sulfonamides was investigated. The HA was applied in two different modes, i.e. pre-coating and co-introduction with sorbate. In pre-coating mode, the polar fractions of HA tended to interact with low-temperature biochars via H-bonding, while the hydrophobic fractions were likely to be adsorbed by high-temperature biochars through hydrophobic and π-π interactions, leading to different composition and structure of the HA adlayers. The influences of HA fractionation on biochar sorption for sulfonamides varied significantly, depending on the nature of interaction between HA fraction and sorbate. Meanwhile, co-introduction of HA with sulfonamides revealed that the effect of HA on sulfonamide sorption was also dependent on HA concentration. These findings suggest that the amount and fractionation of adsorbed HA are tailored by the surface properties of underlying biochars, which differently affect the sorption for organic contaminants. - Highlights: • Effect of quantity and fractionation of coated HA on sorption of sulfonamides by BC was studied. • Fractionation of coated HA is tailored by surface properties of BC. • Roles of HA in BC sorption depend on interaction between HA adlayer and sorbate. • Roles of HA in sulfonamide sorption by BC also depend on HA aqueous concentration. - The quantity and fractionation of adsorbed HA play a major role in sulfonamide sorption by biochars

  16. Sorption of malachite green (MG) by cassava stem biochar (CSB ...

    African Journals Online (AJOL)

    Cassava stem biochar (CSB) was produced by pyrolyzing CS at 500°C for 2 hours at nitrogen environment. Proximate and ultimate analyses were conducted on CS and CSB. Batch sorption experiment on synthetic MG wastewater was optimized for the sorbent dosage, MG solution pH and contact time. Sorption data was ...

  17. Competitive sorption of heavy metals by water hyacinth roots.

    Science.gov (United States)

    Zheng, Jia-Chuan; Liu, Hou-Qi; Feng, Hui-Min; Li, Wen-Wei; Lam, Michael Hon-Wah; Lam, Paul Kwan-Sing; Yu, Han-Qing

    2016-12-01

    Heavy metal pollution is a global issue severely constraining aquaculture practices, not only deteriorating the aquatic environment but also threatening the aquaculture production. One promising solution is adopting aquaponics systems where a synergy can be established between aquaculture and aquatic plants for metal sorption, but the interactions of multiple metals in such aquatic plants are poorly understood. In this study, we investigated the absorption behaviors of Cu(II) and Cd(II) in water by water hyacinth roots in both single- and binary-metal systems. Cu(II) and Cd(II) were individually removed by water hyacinth roots at high efficiency, accompanied with release of protons and cations such as Ca 2+ and Mg 2+ . However, in a binary-metal arrangement, the Cd(II) sorption was significantly inhibited by Cu(II), and the higher sorption affinity of Cu(II) accounted for its competitive sorption advantage. Ionic exchange was identified as a predominant mechanism of the metal sorption by water hyacinth roots, and the amine and oxygen-containing groups are the main binding sites accounting for metal sorption via chelation or coordination. This study highlights the interactive impacts of different metals during their sorption by water hyacinth roots and elucidates the underlying mechanism of metal competitive sorption, which may provide useful implications for optimization of phytoremediation system and development of more sustainable aquaculture industry. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Analysis of ideal sorption compressor cycles operating with gas mixtures

    NARCIS (Netherlands)

    Tzabar, N.; ter Brake, H.J.M.

    2018-01-01

    Sorption-based compressors are thermally driven and because of the absence of moving parts they are vibration free, and have the potential for long life. Sorption-based compressors have been reported to operate Joule–Thomson (JT) cryogenic coolers with pure working fluids. However, using mixed

  19. Picloram and Aminopyralid Sorption to Soil and Clay Minerals

    Science.gov (United States)

    Aminopyralid sorption data are lacking, and these data are needed to predict off-target transport and plant available herbicide in soil solution. The objective of this research was to determine the sorption of picloram and aminopyralid to five soils and three clay minerals and determine if the pote...

  20. Hysteresis and Temperature Dependency of Moisture Sorption – New Measurements

    DEFF Research Database (Denmark)

    Rode, Carsten; Hansen, Kurt Kielsgaard

    2011-01-01

    measurements of hysteresis and temperature dependency of the moisture sorption characteristics of three different porous building materials: aerated concrete, cement paste and spruce. Scanning curves are measured for all three materials where periods with adsorption and desorption interrupt each other...... intermittently. For one of the materials, aerated concrete, the sorption curves are determined at three different temperatures....

  1. Sorption of fluoroquinolones and sulfonamides in 13 Brazilian soils.

    Science.gov (United States)

    Leal, Rafael Marques Pereira; Alleoni, Luis Reynaldo Ferracciú; Tornisielo, Valdemar Luiz; Regitano, Jussara Borges

    2013-08-01

    Animal production is a leading economic activity in Brazil and antibiotics are widely used. However, the occurrence, behavior, and impacts of antibiotics in Brazilian soils are still poorly known. We evaluated the sorption behavior of four fluoroquinolones (norfloxacin, ciprofloxacin, danofloxacin, and enrofloxacin) and five sulfonamides (sulfadiazine, sulfachloropyridazine, sulfamethoxazole, sulfadimidine, and sulfathiazole) in 13 Brazilian soils with contrasting physical, chemical, and mineralogical properties. Fluoroquinolone sorption was very high (Kd≥544 L kg(-1)) whereas sulfonamide sorption ranged from low to high (Kd=0.7-70.1 L kg(-1)), consistent with previous reports in the literature. Soil texture and cation exchange capacity were the soil attributes that most affected sorption. Cation exchange was the most important sorption mechanism for the fluoroquinolones in highly weathered tropical soils, although cation bridging and ion pairing could not be ruled out. Hydrophobic partition played an important role in the sorption of the sulfonamides, but sorption was also affected by non-hydrophobic interactions with organic and/or mineral surfaces. Sorption for both compound classes tended to be higher in soils with high Al and Fe oxihydroxide contents, but they were not correlated with Kd values. No direct effect of soil pH was seen. The fluoroquinolones are not expected to leach even in worst-case scenarios (soils rich in sand and poor in organic carbon), whereas soil attributes dictate leaching potential for the sulfonamides. Copyright © 2013 Elsevier Ltd. All rights reserved.

  2. Oskarshamn site investigation. Batch experiments of I, Cs, Sr, Ni, Eu, U and Np sorption onto soil from the Laxemar area

    Energy Technology Data Exchange (ETDEWEB)

    Holgersson, Stellan (Dept. of Chemical and Biochemical Engineering, Nuclear Chemistry, Chalmers Univ. of Technology, Goeteborg (Sweden))

    2009-04-15

    Soil and groundwater samples from the Laxemar area have been collected and characterised, as have previously been reported. Batch experiments with sorption of radiotracers of I, Cs, Sr, Ni, Eu, U and Np have been made with eight selected soil samples and one natural groundwater. The solid/liquid ratio in the experiments was 1/48 and sampling were made at 3 hours, 1 day, 7 days, 14 days, 40 days and finally 130 days. Phase separation was made by centrifugation field > 20 kG. Experiments were made in an inert-gas glove-box (O{sub 2} < 1 ppm). The same type of batch sorption experiments was also made with a synthetic groundwater. The recipe for the synthetic groundwater was based on the analyses of the natural groundwater, except for dissolved organic matter, which were omitted. A separate series of supporting experiments, without radionuclide tracers, were made for the measurement of the evolution of pH and Eh. Another series of supporting experiments were made for a number of chemical analyses, where samples were taken at 14 and 130 days only: anion and cation chromatography, alkalinity titrations, total organic carbon (TOC), inorganic carbon, pH and Eh measurements, ICP-MS and -OES analyses of background radiotracer elements and a number of other elements. The general trend of the batch sorption results show specific surface corrected distribution coefficients, R{sub a} (m) that increase with time, but the trend is a levelling out to limiting values. Iodine sorption is generally below the lower detection limit and very few data could be collected for this tracer. Eu generally shows the strongest sorption and some measurements at the later samplings are above the upper detection limit. Results from the batch experiments with peat and natural groundwater at 130 days give R{sub a} values that ranges from 5x10-5 (Sr) to 3x10-4 m (Cs). The order of increasing sorption is: Sr, Ni, Np, Eu, U and Cs. For synthetic groundwater Eu and U sorption is stronger, at least

  3. Sorption of Np (Ⅴ) on Beishan granite fracture filling materials

    International Nuclear Information System (INIS)

    Jiang Tao; Wang Bo; Bao Liangjin; Zhou Duo; Long Haoqi; Song Zhixin; Chen Xi

    2012-01-01

    The sorption behaviors of Np (Ⅴ) on the granite fracture filling materials were studied by batch experiments under anaerobic in Beishan groundwater. The impact of pH of groundwater, CO 3 2- , humic acid and different components of granite fracture filling materials on sorption of Np (Ⅴ) was investigated. The results show that the granite fracture filling materials have strong capacity of Np (Ⅴ) adsorption. The value of K d , for Np (Ⅴ) sorption on the granite fracture filling materials is 843 mL/g. With the increase of pH, the value of K d increases at first and then decreases. K d of Np sorption on granite fracture filling materials in the presence of CO 3 2- and humic acid decreases. The chlorite and feldspar are major contributors to the sorption of Np (Ⅴ) on Beishan granite fracture filling materials. (authors)

  4. Sorption of polycyclic aromatic hydrocarbons on particulate organic matters

    International Nuclear Information System (INIS)

    Guo Xueyan; Luo Lei; Ma Yibing; Zhang Shuzhen

    2010-01-01

    Particulate organic matter (POM) is a key organic matter fraction which can influence soil fertility. Its interactions with hydrophobic organic pollutants (HOCs) have not been characterized and the mechanisms of retention of HOCs by POM remain unclear. In the present study, sorption behaviors of polycyclic aromatic hydrocarbons (PAHs) naphthalene (NAP), phenanthrene (PHE), and pyrene (PYR) by POMs separated from different soils were examined and the POMs were characterized by elemental analysis, solid state 13 C NMR, and Fourier transform infrared spectroscopy (FT-IR). The results indicated that POMs were mainly composed of aliphatic components with high polarity. The different original POMs showed similar chemical composition and configuration. Sorption behaviors of PAHs indicated that there was no significant difference in sorption capacity among the POMs. Sorption of NAP and PHE by POMs displayed a nonlinear isotherm, while sorption of PYR yielded a linear isotherm. No significant hysteresis and ionic strength effect were observed for PAH desorption from the POMs.

  5. Sorption of perfluoroalkyl substances to two types of minerals.

    Science.gov (United States)

    Hellsing, Maja S; Josefsson, Sarah; Hughes, Arwel V; Ahrens, Lutz

    2016-09-01

    The sorption of perfluoroalkyl substances (PFASs) was investigated for two model soil mineral surfaces, alumina (Al2O3) and silica (SiO2), on molecular level using neutron scattering. The PFASs were selected (i.e. perfluorohexanoic acid (PFHxA), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), and perfluorooctane sulfonic acid (PFOS)) to examine the role of hydrophobic chain length and hydrophilic functional group on their sorption behaviour. All four PFASs were found to sorb to alumina surface (positively charged) forming a hydrated layer consisting of 50% PFASs. The PFAS solubility limit, which decrease with chain length, was found to strongly influence the sorption behaviour. The sorbed PFAS layer could easily be removed by gentle rinsing with water, indicating release upon rainfall in the environment. No sorption was observed for PFOA and PFOS at silica surface (negatively charged), showing electrostatic interaction being the driving force in the sorption process. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Sorption behaviour of cobalt-60 on Suez Canal bottom sediments

    International Nuclear Information System (INIS)

    Abdel Gawad, S.A.; El-Shinawy, R.M.K.; Abdel Malik, W.E.Y.

    1981-01-01

    Mineralogical, elemental analysis and sorption behaviour of the Suez Canal bottom sediments in the Port Said area were investigated. It was found that the bottom sediment consist mainly of quartz, feldspars and traces of calcite mineral. The cation-exchange capacity was found to increase as the particle size of the sediment decreased. Sorption of 60 Co by the bottom sediment increased with contact time up to 6 h. Variation of the solution pH from 4 to 9 showed limited increase in the sorption of 60 Co. As carrier concentrations increase from 10 -7 N to 10 -3 N, sorption of Co was found to increase linearly following Freundlich isotherm. The presence of Mg 2+ and Fe 3+ in solution depressed the sorption of 60 Co by the sediments. The desorption of 60 Co from bottom sediment with distilled and Suez Canal water was found to increase with contact time. (author)

  7. Recent developments in nanostructured inorganic materials for sorption of cesium and strontium: Synthesis and shaping, sorption capacity, mechanisms, and selectivity-A review.

    Science.gov (United States)

    Alby, Delhia; Charnay, Clarence; Heran, Marc; Prelot, Bénédicte; Zajac, Jerzy

    2018-02-15

    Liquid wastes containing non-ferrous heavy metal ions and some radionuclides, 137 Cs and 90 Sr in particular, represent one of the most dangerous sources of environmental contamination. The remediation of wastewater containing such pollutants continue to be among the biggest challenges of Sustainable Development and Environmental Safety. Sorption-based technologies have proven their efficiency also in reducing the radionuclide content in aqueous streams to low-level residual activity, with the concomitant decrease in the amount of ultimate solid waste generated. Although sorption of cesium and strontium by resins, clays, and zeolites has been investigated intensively and even used in real applications, there is still considerable scope for improvement in terms of retention capacity and selectivity. Recent progress in design and preparation of nanostructured inorganic materials has attracted growing interest based on the potential for improving the retention performance when coupling such functionalities as ion exchange capacity, structural flexibility that may result in steric retention effects, as well as the propensity to interact specifically with the target metal cations. Titanate, vanadate, and tungsten based materials, manganese oxides, hexacyanoferrates, metal sulfides, ammonium molybdophosphates, or hydroxyapatite, characterized by various structures and morphologies, are reviewed with the emphasis being put on synthesis and shaping of such materials, their structure in relationship with the capacity and selectivity of trapping cesium and strontium from either single or multi-component aqueous solutions, as well as the possible retention mechanism. The potential candidates for remediation uses are selected with regard to their sorption capacity and distribution coefficient towards target cations, and also the pH window for an optimum cation capture. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Sorption mechanisms of metals to graphene oxide

    International Nuclear Information System (INIS)

    Showalter, Allison R; Bunker, Bruce A; Duster, Thomas A; Szymanowski, Jennifer E S; Na, Chongzheng; Fein, Jeremy B

    2016-01-01

    Environmental toxic metal contamination remediation and prevention is an ongoing issue. Graphene oxide is highly sorptive for many heavy metals over a wide pH range under different ionic strength conditions. We present x-ray absorption fine structure (XAFS) spectroscopy results investigating the binding environment of Pb(II), Cd(II) and U(VI) ions onto multi-layered graphene oxide (MLGO). Analysis indicates that the dominant sorption mechanism of Pb to MLGO changes as a function of pH, with increasing inner sphere contribution as pH increases. In contrast, the sorption mechanism of Cd to MLGO remains constant under the studied pH range. This adsorption mechanism is an electrostatic attraction between the hydrated Cd +2 ion and the MLGO surface. The U(VI), present as the uranyl ion, changes only subtly as a function of pH and is bound to the surface via an inner sphere bond. Knowledge of the binding mechanism for each metal is necessary to help in optimizing environmental remediation or prevention in filtration systems. (paper)

  9. Mercury Sorption onto Malt Spent Rootlets

    Science.gov (United States)

    Manariotis, I. D.; Anagnostopoulos, V.; Karapanagioti, H. K.; Chrysikopoulos, C.

    2011-12-01

    Mercury is a metal of particular concern due to its toxicity even at relatively low concentrations. The maximum permissible level for mercury in drinking water set by the European Union is 0.001 mg/L. Mercury is released into the environment via four principal pathways: (1) natural processes; i.e. a volcanic eruption, (2) incidental to some other activity; i.e. coal burning power plants, (3) accidentally during the manufacture, breakage or disposal of products that have mercury put into them deliberately, and (4) direct use in industrial settings. The present study focuses on the removal of mercury (II) from aqueous solutions via sorption onto Malt Spent Rootlets (MSR). Batch experiments were conducted employing MSR with size ranging from 0.18 to 1 mm. The effects of pH, mercury concentration, contact time, and solid to liquid ratio on mercury sorption onto MSR were investigated. The highest mercury removal from the aqueous phase, of 41%, was observed at pH of 5.

  10. Tritium sorption by cement and subsequent release

    International Nuclear Information System (INIS)

    Ono, F.; Yamawaki, M.

    1995-01-01

    In a fusion reactor or tritium-handling facilities, contamination of concrete by tritium and subsequent release from it to the reator or experimental room is a matter of problem for safe control of tritium and management of operational environment. In order to evaluate this tritium behavior, interaction of tritiated water with concrete or cement should be clarified. In the present study, HTO sorption and subsequent release from cement were experimentally studied.(1)Sorption experiments were conducted using columns packed with cement particles of different sizes. From the analysis of the breakthrough curve, tritium diffusivity in macropores and microparticles were evaluated.(2)From the short-term tritium release experiments, effective desorption rate constants were evaluated and the effects of temperature and moisture were studied.(3)In the long-term tritium release experiments to 6000h, the tritium release mechanism was found to be composed of three kinds of water: initially from capillary water, and in the second stage from gel water and from the water in the cement crystal.(4)Tritium release behavior by heat treatment to 800 C was studied. A high temperature above 600 C was required for the tritium trapped in the crystal water to be released. (orig.)

  11. Sorption of uranium by cellulose derivatives

    International Nuclear Information System (INIS)

    Muroi, M.; Imai, S.; Hamaguchi, A.

    1985-01-01

    The sorption behaviour of uranium was investigated by batch and column methods using four cellulose derivatives, two having an amino group and two having an amino group plus a dithiocarboxylate group. All four derivatives showed maximum uranium sorption from pure water in the neutral region or from artificial sea water in the acidic region. In the batch method, quantitative removal of 100 μg of uranium from 50 ml of water at pH 5.0 was achieved by equilibration with 50 mg of any of the four sorbents. The percentage removal under these conditions decreased gradually with increasing concentration of uranium above 100 μg per 50 ml. A similar high percentage removal of uranium was achieved using artificial sea water. In the column method, quantitative removal of 5 μg of uranium from 1l of water at pH 6.7 was achieved with 200 mg of either of the two sorbents. Similar quantitative removal of uranium was achieved from 1l of artificial sea water at pH 5.4 with 500 mg of either of the two sorbents. (author)

  12. Uranium sorption on tezontle volcanic rock

    Energy Technology Data Exchange (ETDEWEB)

    Lopez M, B. E.; Duran B, J. M.; Iturbe G, J. L.; Olguin G, M. T., E-mail: beatriz.lopez@inin.gob.m [ININ, Departamento de Quimica, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

    2009-07-01

    It is described a study that demonstrates that hexavalent uranium ions were sorbed by the naturally occurring mineral using a batch technique. This mineral is found in abundant quantities in Mexico. Our study focused on the separation of U Vi from synthetic aqueous systems of both H{sub 2}O-UO{sub 2}(NO{sub 3}){sub 2}.6H{sub 2}O (acid) and H{sub 2}O-Na{sub 4}[UO{sub 2}(CO{sub 3}){sub 3}] (basic). The chemical speciation was performed by using high voltage electrophoresis, and the uranium content was determined by UV-Vis spectroscopy. The quantified U(Vi) sorption by tezontle from acidic and basic systems was 2.72 and 1.68 mumol/g, respectively, and the sorption behavior is discussed considering the surface charge of the tezontle at different ph values based on the point of zero charge characteristic of this material. (Author)

  13. Gas Sorption, Diffusion, and Permeation in Nafion

    KAUST Repository

    Mukaddam, Mohsin Ahmed

    2015-12-22

    The gas permeability of dry Nafion films was determined at 2 atm and 35 °C for He, H2, N2, O2, CO2, CH4, C2H6, and C3H8. In addition, gas sorption isotherms were determined by gravimetric and barometric techniques as a function of pressure up to 20 atm. Nafion exhibited linear sorption uptake for low-solubility gases, following Henry’s law, and convex behavior for highly sorbing condensable gases, indicating rubber-like behavior at 35 °C. XRD results demonstrated that Nafion contains bimodal amorphous chain domains with average d-spacing values of 2.3 and 5.3 Å. Only helium and hydrogen showed relatively high gas permeability of 37 and 7 barrers, respectively; all other gases exhibited low permeability that decreased significantly as penetrant size increased. Dry Nafion was characterized by extraordinarily high selectivities: He/H2 = 5.2, He/CH4 = 445, He/C2H6 = 1275, He/C3H8 = 7400, CO2/CH4 = 28, CO2/C2H6 = 79, CO2/C3H8 = 460, H2/CH4 = 84, H2/C2H6 = 241, and H2/C3H8 = 1400. These high selectivities could make Nafion a potential candidate membrane material for dry feeds for helium recovery and carbon dioxide separation from natural gas and removal of higher hydrocarbons from hydrogen-containing refinery gases.

  14. Status of sorption information retrieval system

    International Nuclear Information System (INIS)

    Hostetler, D.D.; Serne, R.J.; Brandstetter, A.

    1979-09-01

    A Sorption Information Retrieval System (SIRS) is being designed to provide an efficient, computerized, data base for information on radionuclide sorption in geologic media. The data bank will include Kd values for a large number of radionuclides occurring in radioactive wastes originating from the commercial nuclear power industry. Kd values determined to date span several groundwater compositions and a wide variety of rock types and minerals. The data system will not only include Kd values, but also background information on the experiments themselves. This will allow the potential user to retrieve not only the Kd values of interest but also sufficient information to evaluate the accuracy and usefulness of the data. During FY-1979, the logic structure of the system was designed, the software programmed, the data categories selected, and the data format specified. About 40% of the approximately 5000 Kd experiments performed by the Waste Isolation Safety Assessment Program (WISAP) and its subcontractors during FY-1977 and FY-1978 have been evaluated, coded and keypunched. Additional software improvements and system testing are needed before the system will be fully operational. A workshop requested by the NEA was held to discuss potential internatioal participation in the data system

  15. Comparative study on sorption/desorption of radioeuropium on alumina, bentonite and red earth: effects of pH, ionic strength, fulvic acid, and iron oxides in red earth

    International Nuclear Information System (INIS)

    Dong Wenming; Wang Xiangke; Bian Xiaoyan; Wang Aixia; Du Jingzhou; Tao, Z.Y.

    2001-01-01

    The sorption and desorption of Eu(III) as a representative of trivalent lanthanides and actinides on bentonite, alumina, red earth and red earth treated to remove free iron oxides were comparatively investigated by using batch technique and radiotracer 152+154 Eu. The effects of pH, ionic strength, fulvic acid, iron oxides in red earth and the sorption mechanism were also discussed. As compared to alumina and red earth, Eu(III) presents a considerable distribution coefficient (K d ) onto bentonite. It was found that the pH and the presence of clay minerals are the main factors dominating the sorption/desorption characteristic of Eu 3+ in the soil, and that a sorption-desorption hysteresis on bentonite and red earth actually occurs. Furthermore, the main sorption mechanism of lanthanides onto bentonite, alumina and red earth is the formation of bridged hydroxo complexes with the surface, and there are negative effects of fulvic acid and free iron oxides in red earth on the sorption of Eu(III). The results of this paper indicate that the additivity rule on the sorption characteristic of a soil from the individual component's characteristics is not general

  16. Sorption and diffusion of Cs and I in concrete

    International Nuclear Information System (INIS)

    Andersson, K.; Torstenfelt, B.; Allard, B.

    1983-01-01

    Concrete has been suggested as a possible encapsulation material for long-term storage of low and medium level radioactive waste. At an underground storage of concrete encapsulated waste, a slow release of radioactive elements into the groundwater by diffusion through the concrete must be considered in the safety analysis. The diffusion may be delayed by sorption reactions on the solid. A wide range of long-lived radionuclides may be present in the low and medium level radioactive waste. Here, the sorption and diffusion of iodide and cesium on slag cement paste and concrete has been studied. The influence of four different water phases (pore water, groundwater, Baltic Sea water and sea water) as well as the influence of some added species (carbonate, sulphate and magnesium) has been investigated. A significant sorption of iodide on cement paste in contact with pore water was observed, indicating that the diffusion may be expected to be retarded in this medium. For cesium the highest sorption was found for concrete and groundwater. This means that the sorption increases as the concrete is weathered. Low or insignificant sorption was found for the cement paste, indicating that the ballast is responsible for the Cs-sorption. Carbonatization enhances the Cs-sorption by about a factor of 3. The diffusivity of Cs in concrete and cement paste was determined to between 2x10 - 14 and 8x10 - 14 m 2 /s in pore water (where an insignificant sorption was observed). The choice of ballast as well as addition of suitable getters with high sorption of the long-lived radionuclides might decrease the mass transfer rate through the cement. (Authors)

  17. Effect of humic acid on sorption of technetium by alumina

    International Nuclear Information System (INIS)

    Kumar, S.; Rawat, N.; Kar, A.S.; Tomar, B.S.; Manchanda, V.K.

    2011-01-01

    Highlights: → Tc sorption on alumina has been studied under aerobic as well anaerobic condition over pH 3-10. → Effect of humic acid on sorption of Tc by alumina has been investigated. → Linear additive modeling and surface complexation modeling were carried out to delineate the role of humic acid in Tc(IV) sorption in ternary system of Tc(IV)-humic acid-alumina. → Sorption of humic acid onto alumina and strong complexation of Tc(IV) with humic acid were found to govern the sorption of Tc(IV) in the ternary system. - Abstract: Sorption of technetium by alumina has been studied in absence as well as in presence of humic acid using 95 Tc m as a tracer. Measurements were carried out at fixed ionic strength (0.1 M NaClO 4 ) under varying pH (3-10) as well as redox (aerobic and reducing anaerobic) conditions. Under aerobic conditions, negligible sorption of technetium was observed onto alumina both in absence and in presence of humic acid. However, under reducing conditions (simulated with [Sn(II)] = 10 -6 M), presence of humic acid enhanced the sorption of technetium in the low pH region significantly and decreased at higher pH with respect to that in absence of humic acid. Linear additive as well as surface complexation modeling of Tc(IV) sorption in presence of humic acid indicated the predominant role of sorbed humic acid in deciding technetium sorption onto alumina.

  18. Simulation of radionuclide chemistry and sorption characteristics in the geosphere by artificial intelligence technique

    International Nuclear Information System (INIS)

    Liu Shangjyh; National Tsing Hua Univ., Hsinchu; Wang Shigang; Ho Liwei

    1988-01-01

    An expert system operated in a personal computer is employed to simulate chemistry and sorption phenomena of radionuclides in the geosphere. The system handles both qualitative and quantitative analyses primarily for the actinides and fission products. The system also incorporates data bases of several groundwater and rock types with mineral and chemical compositions, the distribution coefficients of nuclides for minerals, etc. The decision rule base facilitates this system to carry out the reasoning procedures to predict the solubility-limiting phase, solute species, oxidation states and possible complex formations of radionuclides, as well as to calculate the distribution coefficients and retardation factors in a geological formation, provided that the essential groundwater and host rock information are available. It is concluded that this device of artificial intelligence provides a vehicle to accumulate developed human knowledge and serves as a tool not only for simulating the complicated radionuclide behaviour in the geosphere, but also for instructional or educational purpose in this field. (orig.)

  19. Sorption and direct speciation of neptunium(V) on aluminium oxide and montmorillonite

    International Nuclear Information System (INIS)

    Wendt, Sonja

    2009-01-01

    This study comprised batch experiments, direct speciation studies via EXAFS, and modelling with the 2SPNE SC/CE model to elucidate the mechanisms of Np(V) sorption on montmorillonite and, for reference, on γ-Al 2 O 3 . The sorption of pM 239 Np(V) and μM 237 Np(V) on montmorillonite (STx-1, 4 g/L) and γ-Al 2 O 3 (0.5 g/L) was studied at room temperature in the presence and absence of ambient CO 2 covering a pH-range from 2.5 (STx-1) or 5 (γ-Al 2 O 3 ) to 10.5 with 0.01 or 0.1M NaClO 4 as background electrolyte. The Np(V) uptake was determined by γ spectroscopy of the supernatants and calculated as percentage as well as distribution coefficient K d . Sorption starts from pH ∼6 and, under exclusion of CO 2 , increases continuously, while, in the presence of ambient air, it reaches a maximum at pH ∝8.5 (γ-Al 2 O 3 : logK d max ∼ 4 mL/g; STx-1: logK d max ∼ 2.7 mL/g). Beyond that it decreases again due to the formation of aqueous neptunium carbonate complexes. Furthermore, neptunium sorption on montmorillonite is influenced by ionic strength at pH <6 through ion exchange processes pointing towards the formation of outer-sphere surface complexes there. Isotherms measured at the sorption maximum showed the precipitation of presumably neptunium carbonate complexes above 3.10 -5 M under ambient air conditions. Additionally, they indicated progressive saturation of the sorption sites of γ-Al 2 O 3 . At selected pH (STx-1: 5.0, 7.0, 8.0, 8.5, 9.0, 9.5; γ-Al 2 O 3 : 8.5, 9.5) EXAFS samples were prepared as wet pastes with μM 237 Np and measured at room temperature in fluorescence mode at ANKA and ESRF. Several spectra were averaged and analysed with EXAFSPAK and FEFF 8.20 employing models of NaNpO 2 (CO 3 ) or soddyite, (UO 2 ) 2 SiO 4 .2(H 2 O). The shorter atomic distances of the neptunyl ion at pH 5 compared to the others hinted at the retention of the hydration shell and, thus, at outer-sphere sorption. On average the bond lengths for Np(V) sorbed on STx

  20. Effect of Temperature on the Kinetics of Sorption of Co2+ and Ni2+ Ions by a Sorbent Based on an Inositol Hexaphosphoric Acid Derivative

    Science.gov (United States)

    Yarusova, S. B.; Makarenko, N. V.; Gordienko, P. S.; Karpenko, M. A.; Novikova, E. S.

    2018-03-01

    Data on the effect temperature has on the kinetics of the removal of Co2+ and Ni2+ ions under static conditions by a sorbent based on a derivative of phytic acid fabricated from rice production waste are presented. It is shown that when the temperature is raised from 20 to 60°C, the sorption capacity of the sorbent based on phytic acid increases over the period of sorption and within 180 min reaches values of 1.4 mmol g-1 for Co2+ ions and 1.3 mmol g-1 for Ni2+ ions. It is established that for the investigated range of temperatures, order n of the sorption of Co2+ and Ni2+ ions is frame is best described by a kinetic model of a pseudo-second order, as is indicated by respective correlation coefficients.

  1. A suggested approach toward measuring sorption and applying sorption data to repository performance assessment

    International Nuclear Information System (INIS)

    Rundberg, R.S.

    1992-01-01

    The prediction of radionuclide migration for the purpose of assessing the safety of a nuclear waste repository will be based on a collective knowledge of hydrologic and geochemical properties of the surrounding rock and groundwater. This knowledge along with assumption about the interactions of radionuclides with groundwater and minerals form the scientific basis for a model capable of accurately predicting the repository's performance. Because the interaction of radionuclides in geochemical systems is known to be complicated, several fundamental and empirical approaches to measuring the interaction between radionuclides and the geologic barrier have been developed. The approaches applied to the measurement of sorption involve the use of pure minerals, intact, or crushed rock in dynamic and static experiments. Each approach has its advantages and disadvantages. There is no single best method for providing sorption data for performance assessment models which can be applied without invoking information derived from multiple experiments. 53 refs., 12 figs

  2. Parametric study of the sorption of Cs(I) and Sr(II) on mixture of bentonite and magnetite using SCM + IEXM

    International Nuclear Information System (INIS)

    Filipska, H.; Stamberg, K.

    2005-01-01

    Full text of publication follows: The behaviour and subsequent fate of released radionuclides in bentonite barrier surrounding the degraded canister is influenced mainly by sorption. We studied sorption processes in such system experimentally and we modelled and simulated them using surface-complexation (SCM) and ion exchange (IExM) models. Our experimental system consisted of: (1) synthetic granitic water with a given ionic strength (0.1 or 0.01 NaNO 3 ), (2) radionuclides studied (10 -6 mol/l CsCl or SrCl 2 .6H 2 O spiked with 137 Cs or 85 Sr), (3) bentonite pre-treated with the aim to remove carbonates, and magnetite as a representative of corrosion products of steel canister. The alkali-metric and acidimetric titrations under exclusion of CO 2 and the percentage of sorption as a function of pH under oxic conditions at room temperature for bentonite, magnetite and their mixtures under different conditions were determined. The resulting data were modelled and appropriate mathematical description was found: SCM non-electrostatic so called Chemical Model (CEM) for the description of sorption on edge sites and ion exchange model (IExM) for sorption on layer sites. Component Additivity Approach (CA) composed of weighted combination of models describing sorption on bentonite and magnetite was verified. In the course of evaluation procedures, the protonation constants, total concentrations of edge sites and layer sites, cation exchange constants and sorption constants for present Cs and Sr forms were obtained by fitting corresponding experimental data. Consequently, CEM+IExM models and the calculated model parameters were used for predictive (simulation) calculations and parametric study of the sorption of Cs(I) and Sr(II) on bentonite, magnetite and their mixtures. The parametric study covered the influence of pH, solid to liquid ratio, bentonite to magnetite ratio, initial concentrations of Cs and Sr, pCO 2 and ionic strength on the values of selectivity coefficients

  3. Sorption of selected pesticides on soils, sediment and straw from a constructed agricultural drainage ditch or pond.

    Science.gov (United States)

    Vallée, Romain; Dousset, Sylvie; Billet, David; Benoit, Marc

    2014-04-01

    Buffer zones such as ponds and ditches are used to reduce field-scale losses of pesticides from subsurface drainage waters to surface waters. The objective of this study was to assess the efficiency of these buffer zones, in particular constructed wetlands, focusing specifically on sorption processes. We modelled the sorption processes of three herbicides [2-methyl-4-chlorophenoxyacetic acid (2,4-MCPA), isoproturon and napropamide] and three fungicides (boscalid, prochloraz and tebuconazole) on four substrates (two soils, sediment and straw) commonly found in a pond and ditch in Lorraine (France). A wide range of Freundlich coefficient (K fads) values was obtained, from 0.74 to 442.63 mg(1 - n) L (n) kg(-1), and the corresponding K foc values ranged from 56 to 3,725 mg(1 - n) L (n) kg(-1). Based on potential retention, the substrates may be classified as straw > sediments > soils. These results show the importance of organic carbon content and nature in the process of sorption. Similarly, the studied pesticides could be classified according to their adsorption capacity as follows: prochloraz > tebuconazole-boscalid > napropamide > MCPA-isoproturon. This classification is strongly influenced by the physico-chemical properties of pesticides, especially solubility and K oc. Straw exhibited the largest quantity of non-desorbable pesticide residues, from 12.1 to 224.2 mg/L for all pesticides. The presence of plants could increase soil-sediment sorption capacity. Thus, establishment and maintenance of plants and straw filters should be promoted to optimise sorption processes and the efficiency of ponds and ditches in reducing surface water pollution.

  4. Experimental study on an innovative multifunction heat pipe type heat recovery two-stage sorption refrigeration system

    International Nuclear Information System (INIS)

    Li, T.X.; Wang, R.Z.; Wang, L.W.; Lu, Z.S.

    2008-01-01

    An innovative multifunction heat pipe type sorption refrigeration system is designed, in which a two-stage sorption thermodynamic cycle based on two heat recovery processes was employed to reduce the driving heat source temperature, and the composite sorbent of CaCl 2 and activated carbon was used to improve the mass and heat transfer performances. For this test unit, the heating, cooling and heat recovery processes between two reactive beds are performed by multifunction heat pipes. The aim of this paper is to investigate the cycled characteristics of two-stage sorption refrigeration system with heat recovery processes. The two sub-cycles of a two-stage cycle have different sorption platforms though the adsorption and desorption temperatures are equivalent. The experimental results showed that the pressure evolutions of two beds are nearly equivalent during the first stage, and desorption pressure during the second stage is large higher than that in the first stage while the desorption temperatures are same during the two operation stages. In comparison with conventional two-stage cycle, the two-stage cycle with heat recovery processes can reduce the heating load for desorber and cooling load for adsorber, the coefficient of performance (COP) has been improved more than 23% when both cycles have the same regeneration temperature of 103 deg. C and the cooling water temperature of 30 deg. C. The advanced two-stage cycle provides an effective method for application of sorption refrigeration technology under the condition of low-grade temperature heat source or utilization of renewable energy

  5. Pervaporation and sorption behavior of zeolite-filled polyethylene glycol hybrid membranes for the removal of thiophene species.

    Science.gov (United States)

    Lin, Ligang; Zhang, Yuzhong; Li, Hong

    2010-10-01

    Polyethylene glycol (PEG)-CuY zeolite hybrid membranes were prepared for sulfur removal from gasoline feed. The sorption and diffusion behavior of typical gasoline components through the hybrid membranes has been investigated by systematic studies of dynamic sorption curves. Influencing factors including feed temperature, permeate pressure, and zeolite content in the membranes on membrane performance have been evaluated. Immersion experiments results showed the preferential sorption of thiophene, which is key in fulfilling the separation of thiophene/hydrocarbon mixtures. The sorption, diffusion, and permeation coefficients of gasoline components in filled membranes are higher than those in unfilled membranes. Pervaporation (PV) and gas chromatography (GC) experiments results corresponded to the discussions on dynamic sorption curves. PV experiments showed that lower permeate pressure meant higher separation performance. The optimum temperature occurred at 383K, and an Arrhenius relationship existed between permeation flux and operating temperature. The CuY zeolite filling led to a significant increase of flux since the porous zeolite provides for more diffusion for small molecules in mixed matrix membranes. The sulfur enrichment factor increased first and then decreased with the increasing zeolite content, which was attributed to the combined influence of complexation force between CuY and thiophenes as well as the trade-off phenomenon between flux and selectivity. At 9 wt% CuY content, a higher permeation flux (3.19 kg/(m(2) h)) and sulfur enrichment factor (2.95) were obtained with 1190 microg/g sulfur content level in gasoline feed. Copyright 2010 Elsevier Inc. All rights reserved.

  6. Fixed bed sorption of phosphorus from wastewater using iron oxide-based media derived from acid mine drainage

    Science.gov (United States)

    Sibrell, Philip L.; Tucker, T.W.

    2012-01-01

    Phosphorus (P) releases to the environment have been implicated in the eutrophication of important water bodies worldwide. Current technology for the removal of P from wastewaters consists of treatment with aluminum (Al) or iron (Fe) salts, but is expensive. The neutralization of acid mine drainage (AMD) generates sludge rich in Fe and Al oxides that has hitherto been considered a waste product, but these sludges could serve as an economical adsorption media for the removal of P from wastewaters. Therefore, we have evaluated an AMD-derived media as a sorbent for P in fixed bed sorption systems. The homogenous surface diffusion model (HSDM) was used to analyze fixed bed test data and to determine the value of related sorption parameters. The surface diffusion modulus Ed was found to be a useful predictor of sorption kinetics. Values of Ed < 0.2 were associated with early breakthrough of P, while more desirable S-shaped breakthrough curves resulted when 0.2 < Ed < 0.5. Computer simulations of the fixed bed process with the HSDM confirmed that if Ed was known, the shape of the breakthrough curve could be calculated. The surface diffusion coefficient D s was a critical factor in the calculation of Ed and could be estimated based on the sorption test conditions such as media characteristics, and influent flow rate and concentration. Optimal test results were obtained with a relatively small media particle size (average particle radius 0.028 cm) and resulted in 96 % removal of P from the influent over 46 days of continuous operation. These results indicate that fixed bed sorption of P would be a feasible option for the utilization of AMD residues, thus helping to decrease AMD treatment costs while at the same time ameliorating the impacts of P contamination.

  7. Sorption of perfluoroalkyl substances (PFASs) to an organic soil horizon - Effect of cation composition and pH.

    Science.gov (United States)

    Campos Pereira, Hugo; Ullberg, Malin; Kleja, Dan Berggren; Gustafsson, Jon Petter; Ahrens, Lutz

    2018-09-01

    Accurate prediction of the sorption of perfluoroalkyl substances (PFASs) in soils is essential for environmental risk assessment. We investigated the effect of solution pH and calculated soil organic matter (SOM) net charge on the sorption of 14 PFASs onto an organic soil as a function of pH and added concentrations of Al 3+ , Ca 2+ and Na + . Often, the organic C-normalized partitioning coefficients (K OC ) showed a negative relationship to both pH (Δlog K OC /ΔpH = -0.32 ± 0.11 log units) and the SOM bulk net negative charge (Δlog K OC  = -1.41 ± 0.40 per log unit mol c g -1 ). Moreover, perfluorosulfonic acids (PFSAs) sorbed more strongly than perfluorocarboxylic acids (PFCAs) and the PFAS sorption increased with increasing perfluorocarbon chain length with 0.60 and 0.83 log K OC units per CF 2 moiety for C 3 -C 10 PFCAs and C 4 , C 6 , and C 8 PFSAs, respectively. The effects of cation treatment and SOM bulk net charge were evident for many PFASs with low to moderate sorption (C 5 -C 8 PFCAs and C 6 PFSA). However for the most strongly sorbing and most long-chained PFASs (C 9 -C 11 and C 13 PFCAs, C 8 PFSA and perfluorooctane sulfonamide (FOSA)), smaller effects of cations were seen, and instead sorption was more strongly related to the pH value. This suggests that the most long-chained PFASs, similar to other hydrophobic organic compounds, are preferentially sorbed to the highly condensed domains of the humin fraction, while shorter-chained PFASs are bound to a larger extent to humic and fulvic acid, where cation effects are significant. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

  8. Sorption of carbamazepine, 17α-ethinylestradiol, iopromide and trimethoprim to biomass involves interactions with exocellular polymeric substances.

    Science.gov (United States)

    Khunjar, Wendell O; Love, Nancy G

    2011-02-01

    The sorption of carbamazepine (CBZ), iopromide (IOP), trimethoprim (TMP) and 17α-ethinylestradiol (EE2) was evaluated using four biomass types (pure ammonia oxidizing bacterial culture, two heterotrophic enrichment cultures with varying levels of oxygenase activity, and a full-scale nitrifying activated sludge (NAS) culture). CBZ and IOP did not sorb to the four biomass types. EE2 did not sorb to the pure culture but sorbed significantly to the heterotrophic cultures and NAS. TMP sorbed to the heterotrophic cultures and NAS, and was not evaluated for the pure culture. Three floc characteristics (hydrophobicity, median particle size, organic matter content) correlated moderately well with the EE2 organic matter sorption coefficient (KOM,EE2). Zeta potential did not correlate well with KOM,EE2 but did with KOM,TMP, indicating that TMP sorption is more influenced by electrostatic factors than EE2. Once divalent cation-linked exocellular polymeric substances (EPS) were removed from flocs, EE2 and TMP sorption to the non-EPS (cellular) fraction decreased by approximately 50%. The correlation between KOM,EE2 for the non-EPS cellular fraction deteriorated while the correlation between KOM,TMP improved. EE2 seemed to sorb more strongly to EPS protein whereas TMP sorbed equally to polysaccharide and protein EPS. Attempts to develop predictive models were not successful. Pharmaceuticals that sorbed to biomass samples underwent biodegradation whereas those that did not sorb were not biodegraded, suggesting a relationship between sorption and pharmaceutical biotransformation. Copyright © 2010 Elsevier Ltd. All rights reserved.

  9. Study of sorption processes of copper on synthetic hydroxyapatite

    International Nuclear Information System (INIS)

    Rosskopfova, O.; Galambos, M.; Ometakova, J.; Rajec, P.; Caplovicova, M.

    2012-01-01

    The sorption of copper on synthetic hydroxyapatite was investigated using a batch method and radiotracer technique. The hydroxyapatite sample prepared by a wet precipitation process was of high crystallinity with Ca/P ratio of 1.688. The sorption of copper on hydroxyapatite was pH independent ranging from 4 to 6 as a result of buffering properties of hydroxyapatite. The adsorption of copper was rapid and the percentage of Cu sorption was >98% during the first 15-30 min of the contact time. The experimental data for sorption of copper have been interpreted in the term of Langmuir isotherm. The sorption of Cu 2+ ions was performed by ion-exchange with Ca 2+ cations on the crystal surface of hydroxyapatite under experimental conditions. The competition effect of Zn 2+ , Fe 2+ and Pb 2+ towards Cu 2+ sorption was stronger than that of Co 2+ , Ni 2+ and Ca 2+ ions. The ability of the bivalent cations to depress the sorption of copper on hydroxyapatite was in the following order Pb 2+ > Fe 2+ > Zn 2+ > Co 2+ ∼ Ni 2+ . (author)

  10. Sorption of U(VI) species on hydroxyapatite

    International Nuclear Information System (INIS)

    Thakur, P.; Moore, R.C.; Choppin, G.R.

    2005-01-01

    The sorption of uranyl (UO 2 2+ ) cations to hydroxyapatite was studied as a function of the amount of sorbent, ionic strength, U(VI) concentration, pH and temperature. The rate of uranyl sorption on hydroxyapatite decreased with increased uranyl concentrations. The amount sorbed decreased with increased ionic strength and increased with pH to a maximum at 7-8. The sorption data for UO 2 2+ were fitted well by the Freundlich and Dubinin-Radushkevich (D-R) isotherms. The anions Cl - , NO 3 - , SO 4 2- and CH 3 COO - decreased the sorption of uranium on hydroxyapatite while S 2 O 3 2- slightly increased it. The sorbed uranium was desorbed by 0.10 M and 1.00 M solutions of HCl and HNO 3 . The thermodynamic parameters for the sorption of UO 2 2+ were measured at temperatures of 298, 313, 323 and 333 K. The temperature dependence confirmed an endothermic heat of sorption. The activation energy for the sorption process was calculated to be +2.75±0.02 kJ/mol. (orig.)

  11. Artificial Weathering of Biotite and Uranium Sorption Characteristics

    International Nuclear Information System (INIS)

    Lee, Seung Yeop; Baik, Min Hoon; Lee, Jae Kwang

    2009-01-01

    An experiment for uranium sorption onto fresh and weathered biotites was performed. After centrifugation, concentrations of uranium in the supernatants were analyzed using ICP-MS, and biotite samples were investigated using XRD and SEM. With powdered biotites (<3 mm in size), we have conducted uranium sorption experiments about fresh and weathered biotites to obtain uranium sorption amounts in various pH conditions. The uranium sorption was not high at a low pH (e.g., pH 3), but increased with increasing pH. There were lower uranium sorption by the weathered biotites than by the fresh ones, and the difference was much larger at higher pH (e.g., pH 11). The lower sorption values of uranium by the weathered biotites may be caused by a change of mineral surfaces and a chemical behavior of surrounding dissolved elements. It seems that the uranium-mineral interaction has been diminished, especially, in the weathered biotite by a destruction and dissolution of preferential sorption sites on the mineral surfaces and by the colloidal formation from dissolved elements.

  12. Mechanisms of metal sorption by biochars: Biochar characteristics and modifications.

    Science.gov (United States)

    Li, Hongbo; Dong, Xiaoling; da Silva, Evandro B; de Oliveira, Letuzia M; Chen, Yanshan; Ma, Lena Q

    2017-07-01

    Biochar produced by thermal decomposition of biomass under oxygen-limited conditions has received increasing attention as a cost-effective sorbent to treat metal-contaminated waters. However, there is a lack of information on the roles of different sorption mechanisms for different metals and recent development of biochar modification to enhance metal sorption capacity, which is critical for biochar field application. This review summarizes the characteristics of biochar (e.g., surface area, porosity, pH, surface charge, functional groups, and mineral components) and main mechanisms governing sorption of As, Cr, Cd, Pb, and Hg by biochar. Biochar properties vary considerably with feedstock material and pyrolysis temperature, with high temperature producing biochars with higher surface area, porosity, pH, and mineral contents, but less functional groups. Different mechanisms dominate sorption of As (complexation and electrostatic interactions), Cr (electrostatic interactions, reduction, and complexation), Cd and Pb (complexation, cation exchange, and precipitation), and Hg (complexation and reduction). Besides sorption mechanisms, recent advance in modifying biochar by loading with minerals, reductants, organic functional groups, and nanoparticles, and activation with alkali solution to enhance metal sorption capacity is discussed. Future research needs for field application of biochar include competitive sorption mechanisms of co-existing metals, biochar reuse, and cost reduction of biochar production. Published by Elsevier Ltd.

  13. Role of interlayer hydration in lincomycin sorption by smectite clays.

    Science.gov (United States)

    Wang, Cuiping; Ding, Yunjie; Teppen, Brian J; Boyd, Stephen A; Song, Cunyi; Li, Hui

    2009-08-15

    Lincomycin, an antibiotic widely administered as a veterinary medicine, is frequently detected in water. Little is known about the soil-water distribution of lincomycin despite the fact that this is a major determinant of its environmental fate and potential for exposure. Cation exchange was found to be the primary mechanism responsible for lincomycin sorption by soil clay minerals. This was evidenced by pH-dependent sorption, and competition with inorganic cations for sorptive sites. As solution pH increased, lincomycin sorption decreased. The extent of reduction was consistent with the decrease in cationic lincomycin species in solution. The presence of Ca2+ in solution diminished lincomycin sorption. Clay interlayer hydration status strongly influenced lincomycin adsorption. Smectites with the charge deficit from isomorphic substitution in tetrahedral layers (i.e., saponite) manifest a less hydrated interlayer environment resulting in greater sorption than that by octahedrally substituted clays (i.e., montmorillonite). Strongly hydrated exchangeable cations resulted in a more hydrated clay interlayer environment reducing sorption in the order of Ca- smectite. X-ray diffraction revealed that lincomycin was intercalated in smectite clay interlayers. Sorption capacity was limited by clay surface area rather than by cation exchange capacity. Smectite interlayer hydration was shown to be a major, yet previously unrecognized, factor influencing the cation exchange process of lincomycin on aluminosilicate mineral surfaces.

  14. Web-based sorption database (KAERI-SDB)

    International Nuclear Information System (INIS)

    Lee, Jae Kwang; Baik, Min Hoon

    2010-10-01

    Radionuclide sorption data is necessary for the safety assessment of radioactive waste disposal. However the accessibility to the nuclide sorption database is limited. The web-based sorption database (KAERI-SDB) was developed to provide sorption data in a convenient way. The development of the KAERI-SDB was achieved by improving the performance of pre-existing sorption DB programme (SDB-21C) and incorporating the user requirement. The KAERI-SDB was designed that users can access it by using a web browser. Main functions of the KAERI-SDB include (1) log-in/join, (2) search and store of sorption data and (3) scatter plot chart and index chart. It is expected that the KAERI-SDB is widely applied to the safety assessment of radioactive waste disposal by enhancing the accessibility to experts and practitioner related the nuclear industry and governmental administration. It is also expected that reliabilities for the radioactive waste disposal increased by opening the web-based sorption DB to public

  15. Water vapor sorption thermodynamics of the Nafion ionomer membrane.

    Science.gov (United States)

    Wadsö, Lars; Jannasch, Patric

    2013-07-18

    The water interactions of polymer electrolyte membranes are of significant interest when these materials are used in, for example, fuel cells. We have therefore studied the sorption thermodynamics of Nafion with a sorption calorimeter that simultaneously measures the sorption isotherm and the mixing (sorption) enthalpy. This unique method is suitable for investigating the sorption thermodynamics of ionic polymers. The measurements were made at 25 °C on a series of samples dried at different temperatures from 25 to 120 °C. The sorption isotherms indicate that the samples dried at 120 °C lost about 0.8 more water molecules per sulfonic group during the drying than did the samples dried at 25 °C, and this result was verified gravimetrically. The mixing enthalpies showed several peaks or plateaus for the samples dried at 60-120 °C. This behavior was seen up to about 2 water molecules per sulfonic group. As these peaks were not directly related to any feature in the sorption isotherm, they probably have their origin in a secondary process, such as a reorganization of the polymer.

  16. Sorption of strontium by magnetically modified yeast cells

    International Nuclear Information System (INIS)

    Hu Yantao; Ji Yanqin; Tian Qing; Shao Xianzhang; Shi Jianhe; Ivo Safarik; Zhang Shengdong; Li Jinying

    2008-01-01

    Magnetically modified fodder's yeast (Kluyveromyces fragilis) cells using water based magnetic fluid, were characterized by scanning electron microscopy (SEM) and Vibrating Sample Magnetometer (VSM). The sorption-desorption properties of Sr 2+ by these yeast cells from nitrate salt of Sr 2+ were studied. The results demonstrated that the Sr 2+ sorption volume by these cells enhanced with increasing pH and reached a plateau between pH 4.0 and 7.0. A minor effect by temperature was observed. The sorption volumes are 19.5 mg/g and 53.5 mg/g from 10 ppm and 40 ppm Sr 2+ solution respectively within 20 min. The sorption of Sr 2+ in these cells can be desorbed under 0.1 mol/L HNO 3 solution. The maximum Sr 2+ sorption volume is 96.7 mg/g at 20℃. The sorption characteristic fits Langmuir model well with 140.8 mg/g calculated maximum sorption volume by these yeast cells. (authors)

  17. On the Kendall Correlation Coefficient

    OpenAIRE

    Stepanov, Alexei

    2015-01-01

    In the present paper, we first discuss the Kendall rank correlation coefficient. In continuous case, we define the Kendall rank correlation coefficient in terms of the concomitants of order statistics, find the expected value of the Kendall rank correlation coefficient and show that the later is free of n. We also prove that in continuous case the Kendall correlation coefficient converges in probability to its expected value. We then propose to consider the expected value of the Kendall rank ...

  18. Plutonium sorption to nanocast mesoporous carbon

    Energy Technology Data Exchange (ETDEWEB)

    Parsons-Moss, Tashi; Wang, Deborah; Jones, Stephen; Olive, Daniel; Nitsche, Heino [California Univ., Berkeley, CA (United States). Dept. of Chemistry; Lawrence Berkeley National Laboratory, Berkeley, CA (United States). Nuclear Science Div.; Tueysuez, Harun [Lawrence Berkeley National Laboratory, Berkeley, CA (United States). Nuclear Science Div.; Max-Planck-Institut fuer Kohlenforschung, Muelheim an der Ruhr (Germany)

    2014-09-01

    Nanocast ordered mesoporous carbons are attractive as sorbents because of their extremely high surface areas and large pore volumes. This paper compares Pu uptake, added as Pu(VI), to both untreated and chemically oxidized CMK-(carbon molecular sieves from KAIST) type mesoporous carbon with that to a commercial amorphous activated carbon. The CMK was synthesized via nanocasting by using cubic ordered mesoporous silica KIT-6 as a hard template, and characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), and nitrogen adsorption. A portion of the CMK was oxidized by treatment with nitric acid, and will be called OX CMK. The three carbon powders have similar particle morphology, and high BET surface areas. The activated carbon is disordered, while the CMK materials show large domains of ordered cubic mesostructure. The CMK material seems to have more oxygen-containing functional groups than the activated carbon, and the oxidation of the CMK increased the density of these groups, especially - COOH, thus lowering the point of zero charge (PZC) of the material. Batch studies of all 3 materials with plutonium solutions, in a 0.1 M NaClO{sub 4} matrix were performed to investigate pH dependence, sorption kinetics, Pu uptake capacities, competition with ethylenediaminetetraacetic acid (EDTA) in solution, and Pu desorption. Both CMK materials demonstrated high Pu sorption from solutions of pH 3 or greater, and the oxidized CMK also showed high sorption from pH 2 solutions. The activated carbon bound less Pu, and at a much slower rate than CMK. All other batch experiments were carried out in pH 4 solutions. The Pu uptake from low-concentration solutions was faster for the oxidized CMK than for untreated CMK, but in more concentrated samples (∝ 250 μM Pu), the Pu uptake kinetics and apparent capacity were the same for oxidized and untreated CMK. The 23-h Pu uptake capacity of the CMK

  19. Sorption compressor/mechanical expander hybrid refrigeration

    Science.gov (United States)

    Jones, J. A.; Britcliffe, M.

    1987-01-01

    Experience with Deep Space Network (DSN) ground-based cryogenic refrigerators has proved the reliability of the basic two-stage Gifford-McMahon helium refrigerator. A very long life cryogenic refrigeration system appears possible by combining this expansion system or a turbo expansion system with a hydride sorption compressor in place of the usual motor driven piston compressor. To test the feasibility of this system, a commercial Gifford-McMahon refrigerator was tested using hydrogen gas as the working fluid. Although no attempt was made to optimize the system for hydrogen operation, the refrigerator developed 1.3 W at 30 K and 6.6 W at 60 K. The results of the test and of theoretical performances of the hybrid compressor coupled to these expansion systems are presented.

  20. Retention/sorption and geochemical modelling

    Energy Technology Data Exchange (ETDEWEB)

    Arcos, D.; Grandia, F.; Domenech, C. [Enviros Spain, S.L., Barcelona (Spain); SCK-CEN, Mol (Belgium); Sellin, P. [SKB - Swedish Nuclear Fuel and Waste Management, SE, Stockholm (Sweden); Hunter, F.M.I.; Bate, F.; Heath, T.G.; Hoch, A. [Serco Assurance, Oxfordshire (United Kingdom); Werme, L.O. [SKB - Svensk Karnbranslehantering AB, Stockholm (Sweden); Bruggeman, C.; Maes, I.A.; Breynaert, E.; Vancluysen, J. [Leuven Katholieke Univ., Lab. for Colloid Chemistry (Belgium); Montavon, G.; Guo, Z. [Ecole des Mines, 44 - Nantes (France); Riebe, B.; Bunnenberg, C.; Meleshyn, A. [Leibniz Univ. Hannover, Zentrum fur Strahlenschutz und Radiookologie, Hannover (Germany); Dultz, S. [Leibniz Univ. Hannover, Institut fur Bodenkunde, Hannover (Germany)

    2007-07-01

    This session gathers 4 articles dealing with: the long-term geochemical evolution of the near field of a KBS-3 HLNW repository: insights from reactive transport modelling (D. Arcos, F. Grandia, C. Domenech, P. Sellin); the investigation of iron transport into bentonite from anaerobically corroding steel: a geochemical modelling study (F.M.I. Hunter, F. Bate, T.G. Heath, A. Hoch, L.O. Werme); SeO{sub 3}{sup 2-} adsorption on conditioned Na-illite: XAS spectroscopy, kinetics, surface complexation model and influence of compaction (C. Bruggeman, A. Maes, G. Montavon, E. Breynaert, Z. Guo, J. Vancluysen); the influence of temperature and gamma-irradiation on the anion sorption capacity of modified bentonites (B. Riebe, C. Bunnenberg, A. Meleshyn, S. Dultz)

  1. Sorption of radionuclides on a soil

    International Nuclear Information System (INIS)

    Fukui, Masami

    1979-01-01

    Disposal of radioactive wastes into the ground has been discussed, and this paper emphasized significance of the investigation for underground water flow and for the prediction of radionuclides through a stratified aquifer using column experiments to evaluate the internal radiation dose. Distributions and redistributions of radionuclides in a sandy layer were observed to identify the sorption model which predicts the behavior, and the underground water flow in the Plio-Pleistocene Osaka Group was investigated as an example, by mean of the measurement of 222 Rn concentration, the pumping technique and the tracer technique using the activation analysis. Then, the estimation of radioactive concentration in the underground water was worked out for the boundary condition of steady state inflow of liquid wastes and of which the 90 Sr are leached from the solidified body, moreover, the equation which easily evaluates the suitability of the disposal site was proposed. These approach may be useful for the actual site selection of radioactive wastes disposal. (author)

  2. Study of the radium sorption/desorption on goethite

    International Nuclear Information System (INIS)

    Bassot, S.; Stammose, D.; Mallet, C.; Lefebvre, C.; Ferreux, J.-M.

    2000-01-01

    The oxi-hydroxides, present at trace level in uranium mill tailings, are responsible of about 70% of the 226 radium sorption, half being fixed on crystallized forms. This radionuclide (half time=1622y), present at high level (50 to 100kBq.kg -1 ), can be released in groundwater, involving a possible contamination of the food chain (actual concentration limit=0.37Bq.1 -1 ). So, it is very important to point out the mechanisms of the radium sorption/desorption on crystallized oxi-hydroxides as a function of chemical conditions of the system. The radium sorption on synthetic goethite α-FeOOH has been studied as a function of contact time, initial radium activity, pH, sodium and calcium concentrations. The results show that, after one hour of contact time (necessary to reach equilibrium), the radium sorption increases widely in a pH range 6-7. The increase of Na + concentration is without influence on the radium sorption, indicating the low interactions between sodium and surface sites. At the opposite, the presence of calcium in solution decreases widely the radium sorption, that indicates a competition between calcium and radium for the same kind of sorption sites of the oxi-hydroxide surface. The percentage of radium desorbed increases widely with time, from 1 to 120h and becomes constant at a time higher than 120h. This long equilibrium time for desorption in comparison with sorption one can be explain by a local evolution of the sorption sites of the solid, which become less accessible for the solution in contact. (author)

  3. Influence of the nature of soil organic matter on the sorption behaviour of pentadecane as determined by PLS analysis of mid-infrared DRIFT and solid-state {sup 13}C NMR spectra

    Energy Technology Data Exchange (ETDEWEB)

    Clark Ehlers, G.A. [Institute of Environmental Biotechnology, Department IFA-Tulln, University of Natural Resources and Applied Life Sciences, Vienna, Konrad Lorenz Str. 20, Tulln A-3430 (Austria); Forrester, Sean T. [CSIRO Land and Water, Waite Rd, Urrbrae SA 5064 (Australia); Scherr, Kerstin E. [Institute of Environmental Biotechnology, Department IFA-Tulln, University of Natural Resources and Applied Life Sciences, Vienna, Konrad Lorenz Str. 20, Tulln A-3430 (Austria); Loibner, Andreas P., E-mail: andreas.loibner@boku.ac.a [Institute of Environmental Biotechnology, Department IFA-Tulln, The University of Natural Resources and Applied Life Sciences, Vienna, Konrad Lorenz Str. 20, Tulln A-3430 (Austria); Janik, Les J. [CSIRO Land and Water, Waite Rd, Urrbrae SA 5064 (Australia)

    2010-01-15

    The nature of soil organic matter (SOM) functional groups associated with sorption processes was determined by correlating partitioning coefficients with solid-state {sup 13}C nuclear magnetic resonance (NMR) and diffuse reflectance mid-infrared (DRIFT) spectral features using partial least squares (PLS) regression analysis. Partitioning sorption coefficients for n-pentadecane (n-C{sub 15}) were determined for three alternative models: the Langmuir model, the dual distributed reactive domain model (DRDM) and the Freundlich model, where the latter was found to be the most appropriate. NMR-derived constitutional descriptors did not correlate with Freundlich model parameters. By contrast, PLS analysis revealed the most likely nature of the functional groups in SOM associated with n-C{sub 15} sorption coefficients (K{sub F}) to be aromatic, possibly porous soil char, rather than aliphatic organic components for the presently investigated soils. High PLS cross-validation correlation suggested that the model was robust for the purpose of characterising the functional group chemistry important for n-C{sub 15} sorption. - NMR/IR spectroscopy and chemometrics reveal the aromatic fraction of soil organic matter being responsible for alkane sorption.

  4. Sorption of Metal Ions on Clay Minerals.

    Science.gov (United States)

    Schlegel; Manceau; Chateigner; Charlet

    1999-07-01

    The local structural environment of Co sorbed on hectorite (a magnesian smectite) has been investigated by polarized EXAFS (P-EXAFS) spectroscopy on a self-supporting film of Co-sorbed hectorite. This sorption sample was prepared by contacting Co and hectorite at pH 6.5 and at high ionic strength (0.3 M NaNO3) to favor pH-dependent sorption reaction over cation exchange. A self-supporting film was elaborated after 120 h of reacting time, when apparent quasi-equilibrium conditions were attained. The half-width at half maximum of the orientation distribution of c* axis of individual clay platelets off the film normal was determined by quantitative texture analysis, and found to be equal to 18.9 degrees. Co K-edge P-EXAFS spectra were recorded at angles between the incident beam and the film normal equal to 0 degrees, 35 degrees, 50 degrees, and 60 degrees; the 90 degrees spectrum was obtained by extrapolation. Spectral analysis led to the identification of the two nearest cationic subshells containing 1.6 +/- 0.4 Mg at 3.03 Å and 2.2 +/- 0.5 Si at 3.27 Å. These distances are respectively characteristic of edge-sharing linkages between Mg and Co octahedra and of corner-sharing linkages between Co octahedra and Si tetrahedra, as in clay structures. The angular dependence of the Co-Mg and Co-Si contributions indicates that Co-Mg pairs are oriented parallel to the film plane, whereas Co-Si pairs are not. These results are interpreted by the formation of Co inner-sphere mononuclear surface complexes located at the edges of hectorite platelets, in the continuity of the (Mg, Li) octahedral sheet. Copyright 1999 Academic Press.

  5. SORPTION OF Cu2+ IONS ONTO DIATOMITE CONSTITUENTS

    Directory of Open Access Journals (Sweden)

    Vasile Rusu

    2009-06-01

    Full Text Available Studies of the sorption capacity towards Cu2+ ions of diatomite from the Ghidirim location of RM, as well as of the extracted clay phase are presented. Separated clay fraction from diatomic material is clean enough, and especially is rich in montmorillonite. Maximum sorption capacity for studied clay fraction is achieved by rising the temperature of calcination treatment up to 200oC. At higher temperatures the lattice of montmorillonite is contracted and its sorption capacity towards Cu2+ ions decreases strongly.

  6. Modeling and Prediction of Soil Water Vapor Sorption Isotherms

    DEFF Research Database (Denmark)

    Arthur, Emmanuel; Tuller, Markus; Moldrup, Per

    2015-01-01

    Soil water vapor sorption isotherms describe the relationship between water activity (aw) and moisture content along adsorption and desorption paths. The isotherms are important for modeling numerous soil processes and are also used to estimate several soil (specific surface area, clay content.......93) for a wide range of soils; and (ii) develop and test regression models for estimating the isotherms from clay content. Preliminary results show reasonable fits of the majority of the investigated empirical and theoretical models to the measured data although some models were not capable to fit both sorption...... directions accurately. Evaluation of the developed prediction equations showed good estimation of the sorption/desorption isotherms for tested soils....

  7. Sorption and desorption of diuron in Oxisol under biochar application

    OpenAIRE

    Petter, Fabiano André; Ferreira, Tamara Santos; Sinhorin, Adilson Paulo; Lima, Larissa Borges de; Morais, Leidimar Alves de; Pacheco, Leandro Pereira

    2016-01-01

    ABSTRACT The objective of this study was to verify the kinetics of sorption and desorption of diuron in an Oxisol under application of biochar. The samples were collected in a field experiment conducted in randomized design blocks consisted of 2 base fertilization levels (0 and 400 kg∙ha−1 NPK 00-20-20 fertilizer formula) and 3 doses of biochar (0, 8 and 16 Mg∙ha−1). In the evaluation of sorption and desorption, Batch Equilibrium method was used. The kinetics of sorption and desorption of diu...

  8. Interim report on modeling sorption with EQ3/6

    International Nuclear Information System (INIS)

    Viani, B.

    1988-01-01

    Reversible, equilibrium models of sorption to be incorporated into the EQ3/6 geochemical modeling package are summarized. Empirical sorption models as formulated in linear, Langmuir, and Freundlich isotherms will be developed as options to EQ3/6. This work will be done at LLNL. Options for modeling sorption using surface- complexation constructs (diffuse, constant capacitance, and triple-layer models) will also be developed. Development of the surface-complexation options will require part of the work be done under contract. 27 refs., 1 fig

  9. Implementation of sorption hysteresis in multi-Fickian moisture transport

    DEFF Research Database (Denmark)

    Frandsen, Henrik Lund; Svensson, Staffan

    2007-01-01

    In the cellular structure of wood, bound-water diffusion and water-vapor diffusion interact via sorption in a complex moisture-transportation system. At low relative humidities, moisture transport may be modeled by a Fickian diffusion equation with a good approximation. At higher relative......-35% in moisture content. Hence, for a precise moisture content computation, sorption hysteresis must be taken into account. The present paper explains the relation between sorption hysteresis and multi-Fickian moisture transport, and clarifies how models for the two phenomena are coupled. To illustrate...

  10. Sorption of molybdenum by cellulose polyphosphate from acid solutions

    International Nuclear Information System (INIS)

    Luneva, N.K.; Oputina, A.G.; Ermolenko, I.N.

    1985-01-01

    The sorption of molybdenum on cellulose polyphosphate from acid solutions of ammonium molybdate depending on the phosphorus content in samples, concentration and pH of the solution, sorption time is studied. It is shown that a maximum molybdenum content on the cellulose samples with different phosphorus content is pointed out at an ammonium molybdate concentration 0.02 M. Saturation of the sorption curve is attained at molar ratio of adsrbed molybdenum to phosphorus 1:4. In case of small fillings the compound with molybdenum to phosphorus ratio 1:10 is formed

  11. Sorption of Co2+ on modified inorganic materials

    International Nuclear Information System (INIS)

    Hanzel, R.; Rajec, P.

    1999-01-01

    The aim of this study was preparation and characterization of sorbents on the base a silica-gel matrix with immobilized functional group (imidazole or crown-ether). Sorption of cobalt from aqueous solutions on prepared sorbents in static conditions (by 'batch' method) in the dependence of concentration, pH value,, as well as kinetics of sorption were studied. The influence of heavy or toxic metals [Hg(II), Cd(II), Mn(II), Zn(II), Cu(II), Fe(III), Cr(III), Al(III), Na and K] on sorption of cobalt was studied, too

  12. Arsenic Sorption on Mechanically Activated Magnetite and Olivine

    Directory of Open Access Journals (Sweden)

    Zdenka Bujňáková

    2012-12-01

    Full Text Available Arsenic sorption on mechanically activated minerals such as magnetite Fe3O4 (Kiruna, Sweden and olivine (Mg,Fe2SiO4 (Ǻheim,Norway has been studied and compared in this work. Experiments were carried out with non-activated and mechanically activatedsamples. The activation of both minerals was performed in a planetary mill at different milling conditions. The specific surface areaand consequent sorption activity were enhanced by mechanical activation. The using of olivine seems to be better than magnetite fromthe point of view of milling time, which is necessary for achievement of the same sorption effect.

  13. Sorption of trace cesium on 21 Hanford Site sediment types

    International Nuclear Information System (INIS)

    Routson, R.C.; Barney, G.S.; Smith, R.M.; Delegard, C.A.

    1980-03-01

    Sorption of trace cesium (Cs) was measured on 21 Hanford Site sediment types. A Box-Behnken statistical design was used to develop empirical-statistical equations predicting 137 Cs sorption as a function of the equilibrium concentrations of macroions Na + , K + , and Ca +2 in solution over the concentration ranges of 3.0 to 0.001M, 0.2 to 0.002M, and 0.2 to 0.002M, respectively. These equations are required to estimate trace Cs transport from Hanford ground disposal sites. Average Cs sorption equations for the 21 sediments will be presented and discussed

  14. Modelling Zn(II) sorption onto clayey sediments using a multi-site ion-exchange model

    International Nuclear Information System (INIS)

    Tertre, E.; Beaucaire, C.; Coreau, N.; Juery, A.

    2009-01-01

    In environmental studies, it is necessary to be able to predict the behaviour of contaminants in more or less complex physico-chemical contexts. The improvement of this prediction partly depends on establishing thermodynamic models that can describe the behaviour of these contaminants and, in particular, the sorption reactions on mineral surfaces. In this way, based on the mass action law, it is possible to use surface complexation models and ion exchange models. Therefore, the aim of this study is (i) to develop an ion-exchange model able to describe the sorption of transition metal onto pure clay minerals and (ii) to test the ability of this approach to predict the sorption of these elements onto natural materials containing clay minerals (i.e. soils/sediments) under various chemical conditions. This study is focused on the behaviour of Zn(II) in the presence of clayey sediments. Considering that clay minerals are cation exchangers containing multiple sorption sites, it is possible to interpret the sorption of Zn(II), as well as competitor cations, by ion-exchange equilibria with the clay minerals. This approach is applied with success to interpret the experimental data obtained previously in the Zn(II)-H + -Na + -montmorillonite system. The authors' research team has already studied the behaviour of Na + , K + , Ca 2+ and Mg 2+ versus pH in terms of ion exchange onto pure montmorillonite, leading to the development of a thermodynamic database including the exchange site concentrations associated with montmorillonite and the selectivity coefficients of Na + , K + , Ca 2+ , Mg 2+ , and Zn 2+ versus H + . In the present study, experimental isotherms of Zn(II) on two different sediments in batch reactors at different pH and ionic strengths, using NaCl and CaSO 4 as electrolytes are reported. Assuming clay minerals are the main ion-exchanging phases, it is possible to predict Zn(II) sorption onto sediments under different experimental conditions, using the previously

  15. Experimental testing of a small sorption air cooler using composite material made from natural siliceous shale and chloride

    International Nuclear Information System (INIS)

    Liu, Hongzhi; Nagano, Katsunori; Morita, Atsushi; Togawa, Junya; Nakamura, Makoto

    2015-01-01

    A sorption air cooler experimental setup including a reactor and fin tube condenser/evaporator was built. The reactor was developed with inner copper fins and dual layers of curing copper meshes. Composite material made by impregnating LiCl into the mesopores of Wakkanai Siliceous Shale (WSS) micropowders was packed between the intervals of two fins. Heat transfer was enhanced by the attached fins, and the dual layers of curing meshes installed between each interval of two fins were designed to improve the sorbate mass transfer. On the other hand, the fin-tube evaporator/condenser with fins outside is valuable for improving the convective heat transfer between the functional water inside the evaporator/condenser and the flowing outside heat transfer medium, air. The sorption capacity of the composite material increased dramatically after being impregnated with LiCl. Among the four tested samples, WSS + 40 wt% LiCl exhibits the best performance. A regeneration temperature of 80 °C appears to be optimal for obtaining both a high COP and high specific cooling power. A lower condensation temperature can increase the cooling power. The sorption and desorption times of 60 min yield a reasonable compromise between cooling COP and mass specific cooling powers. The developed sorption air cooler system using WSS + 40 wt% LiCl can store heat at temperatures below 100 °C and produce cooling energy with a cooling coefficient of performance (COP) of approximately 0.3. - Highlights: • Mesoporous composite material was developed using natural siliceous shale and LiCl. • Properties of the developed material were measured. • A sorption air cooler experimental setup including an inner-fin reactor and a fin tube condenser/evaporator was built. • The performance of the composite material in the sorption air cooler was examined. • The sorption air cooler system can produce cooling energy with a cooling COP around 0.3

  16. Integrated sorption and diffusion model for bentonite. Part 1. Clay-water interaction and sorption modeling in dispersed systems

    International Nuclear Information System (INIS)

    Tachi, Yukio; Suyama, Tadahiro; Ochs, Michael

    2014-01-01

    To predict the long-term migration of radionuclides (RNs) under variable conditions within the framework of safety analyses for geological disposal, thermodynamic sorption models are very powerful tools. The integrated sorption and diffusion (ISD) model for compacted bentonite was developed to achieve a consistent combination of clay–water interaction, sorption, and diffusion models. The basic premise considered in the ISD model was to consistently use the same simple surface model design and parameters for describing RNs sorption/diffusion as well as clay surface and porewater chemistry. A simple 1-site non-electrostatic surface complexation model in combination with a 1-site ion exchange model was selected to keep sorption model characteristics relatively robust for compacted systems. Fundamental parameters for the proposed model were evaluated from surface titration data for purified montmorillonite. The resulting basic model was then parameterized on the basis of selected published sorption data-sets for Np(V), Am(III), and U(VI) in dispersed systems, which cover a range of key geochemical conditions such as pH, ionic strength, and carbonate concentration. The sorption trends for these RNs can be quantitatively described by the model considering a full suite of surface species including hydrolytic and carbonate species. The application of these models to the description of diffusive-sorptive transport in compacted bentonites is presented in Part 2. (author)

  17. Development of a Self-Consistent Model of Plutonium Sorption: Quantification of Sorption Enthalpy and Ligand-Promoted Dissolution

    Energy Technology Data Exchange (ETDEWEB)

    Powell, Brian [Clemson Univ., SC (United States); Kaplan, Daniel I [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Arai, Yuji [Univ. of Illinois, Urbana-Champaign, IL (United States); Becker, Udo [Univ. of Michigan, Ann Arbor, MI (United States); Ewing, Rod [Stanford Univ., CA (United States)

    2016-12-29

    This university lead SBR project is a collaboration lead by Dr. Brian Powell (Clemson University) with co-principal investigators Dan Kaplan (Savannah River National Laboratory), Yuji Arai (presently at the University of Illinois), Udo Becker (U of Michigan) and Rod Ewing (presently at Stanford University). Hypothesis: The underlying hypothesis of this work is that strong interactions of plutonium with mineral surfaces are due to formation of inner sphere complexes with a limited number of high-energy surface sites, which results in sorption hysteresis where Pu(IV) is the predominant sorbed oxidation state. The energetic favorability of the Pu(IV) surface complex is strongly influenced by positive sorption entropies, which are mechanistically driven by displacement of solvating water molecules from the actinide and mineral surface during sorption. Objectives: The overarching objective of this work is to examine Pu(IV) and Pu(V) sorption to pure metal (oxyhydr)oxide minerals and sediments using variable temperature batch sorption, X-ray absorption spectroscopy, electron microscopy, and quantum-mechanical and empirical-potential calculations. The data will be compiled into a self-consistent surface complexation model. The novelty of this effort lies largely in the manner the information from these measurements and calculations will be combined into a model that will be used to evaluate the thermodynamics of plutonium sorption reactions as well as predict sorption of plutonium to sediments from DOE sites using a component additivity approach.

  18. Environmental Conditions Influencing Sorption of Inorganic Anions to Multiwalled Carbon Nanotubes Studied by Column Chromatography.

    Science.gov (United States)

    Metzelder, Florian; Schmidt, Torsten C

    2017-05-02

    Sorption to carbon-based nanomaterials is typically studied in batch experiments. An alternative method offering advantages to study sorption is column chromatography. Sorbent packed columns are used and sorption data are determined by relating sorbate retention to that of a nonretarded tracer. We have now for the first time applied this technique to study the influence of environmental conditions on sorption of inorganic anions (bromide, nitrite, nitrate, and iodide) to multiwalled carbon nanotubes. Deuterium oxide was used as nonretarded tracer. Sorption isotherms were best described by the Freundlich model. Sorption increased in the order bromide 4.5 the surface charge was negative, but sorption was still detectable at pH 6 and 9. Consequently, other forces than electrostatic attraction contributed to sorption. These forces may include H-bonding as indicated by sorption enthalpy determined by variation of column temperature. Overall, column chromatography represents a promising alternative in sorption studies to reveal sorbent properties.

  19. Sorption (Kd) measurements on cinder block and grout in support of dose assessments for Zion Nuclear Station decommissioning

    Energy Technology Data Exchange (ETDEWEB)

    Milian L.; Sullivan T.

    2014-06-24

    The Zion Nuclear Power Station is being decommissioned. ZionSolutions proposes to leave much of the below grade structures in place and to fill them with a backfill to provide structural support. Backfills under consideration include “clean” concrete demolition debris from the above grade parts of the facility, a flowable grout, cinder block construction debris and sand. A previous study (Yim, 2012) examined the sorption behavior of five nuclides (Fe-55, Co-60, Ni-63, Sr-85, and Cs-137) on concrete and local soils. This study, commissioned by ZionSolutions and conducted by the Brookhaven National Laboratory (BNL) examines the sorption behavior on cinder block and grout materials. Specifically, this study measured the distribution coefficient for four radionuclides of concern using site-groundwater and cinder block from the Zion site and a flowable grout. The distributions coefficient is a measure of the amount of the radionuclide that will remain sorbed to the solid material that is present relative to the amount that will remain in solution. A high distribution coefficient indicates most of the radionuclide will remain on the solid material and will not be available for transport by the groundwater. The radionuclides examined in this set of tests were Co-60, Ni-63, Sr-85, and Cs-137. Tests were performed following ASTM C1733-10, Standard Test Methods for Distribution Coefficients of Inorganic Species by the Batch Method. Sr-85 was used in the testing as an analogue for Sr-90 because it behaves similarly with respect to sorption and has a gamma emission that is easier to detect than the beta emission from Sr-90.

  20. The selection and use of a sorption database for the geosphere model in the Canadian nuclear fuel waste management program

    International Nuclear Information System (INIS)

    Vandergraaf, T.T.; Ticknor, K.V.; Melnyk, T.W.

    1992-01-01

    An extensively characterized intrusive granitic formation, the Lac du Bonnet batholith, is being used as a test case for environmental and safety assessment calculations of the impact of a hypothetical disposal vault. The conceptual vault has dimensions of 2 x 2 km and is located at a depth of 500 m, near the Whiteshell Nuclear Research Establishment (WNRE) (CANADA). Hydraulic investigations of the batholith have shown that the bulk of the groundwater flow will be limited to the existing network of water-bearing fractures. Groundwater flow and contaminant transport modelling is based on a porous-medium concept for both the fracture systems and the rock matrix. Geochemical investigations have identified a number of alteration minerals in these fracture systems. The geochemistry encountered along the flow field is too complex to allow the interaction of radionuclides with the geological material to be represented by a single sorption coefficient for each radionuclide on a single rock type. However, the level of understanding of radionuclide interaction with geological materials is not sufficiently well developed to calculate radionuclide transport using models based on chemical thermodynamics or on advanced sorption models based on surface complexation or mass action. Instead, a parametric model has been developed using the total dissolved solids and radionuclide concentrations as independent variables. The mineralogical complexity of the flow field is addressed by selecting sorption data on the nine most commonly occurring fracture infilling minerals in this batholith, four common rock-forming minerals, and on altered and unaltered granite. This approach produces two polynomial equations for each radionuclide/mineral combination, one under oxic and one under anoxic conditions. Where insufficient information is available, these polynomial expressions are reduced to an equation with one variable or to a single sorption coefficient. 48 refs., 6 figs., 4 tabs

  1. Sorption Kinetics of Escherichia coli and Salmonella sp on Two Soil Layers Associated with a Groundwater Table in Yaounde, Cameroon (Central Africa

    Directory of Open Access Journals (Sweden)

    Norbert Kemka

    2005-12-01

    Full Text Available A laboratory study has been carried out on two soil layers (HX and HY located above a groundwater table in Yaounde, Cameroon (Central Africa. The main purpose of this study was to assess the retention potential or sorption kinetics of Escherichia coli and Salmonella sp. on these soil layers. For both soil layers, bacterial sorption on soil particles occurred rapidly during the first 30 minutes of incubation of bacteria and soil particles in aqueous media, and increased gradually with incubation time up to 300 min. In some cases, adsorption rates fluctuated after 30 min of incubation, probably due to bacterial cell sorption to and de-sorption from soil particles. Using Freundlich isotherms, it was noted that adsorption coefficient related to adsorption capacity varied from 19 to 4026 E. coli.mg-1 of soil, and from 506 to 847 Salmonella sp.mg-1 of soil. For both bacterial species, the adsorption coefficient of layer HY (located in close proximity of the water table was greater than that of HX (located above layer HY and seemed to positively correlate with the pH values and N/P ratios, and to negatively correlate with the values of C/N and C/P ratios. The linearity coefficient related to adsorption intensity varied from 0.5841 to 1.0023 for E. coli, and from 0.7068 to 1.5236 for Salmonella sp. The physico-chemical characteristics of soil particles seemed to influence the sorption kinetics of bacteria on soil.

  2. The interaction of sorbing and non-sorbing tracers with different Aespoe rock types. Sorption and diffusion experiments in the laboratory scale

    International Nuclear Information System (INIS)

    Byegaard, J.; Johansson, Henrik; Skaalberg, M.

    1998-11-01

    Laboratory experiments studying the sorption and diffusivity of different tracers in Aespoe Hard Rock Laboratory (Aespoe HRL) site specific conditions have been performed. The experiments were conducted by applying both the batch sorption and the through diffusion technique. The investigation was focused on slightly sorbing tracers, i e, alkaline metals (Na + , Rb + and Cs + ) and alkaline earth metals (Ca 2+ , Sr 2+ and Ba 2+ ), but some presumed non-sorbing species have also been included. The dominating generic rock material from Aespoe HRL, Aespoe-diorite and fine-grained granite, were used as well as some altered wall rock and mylonite from the Feature A fracture, the fracture where in situ migration studies have been performed. Synthetic groundwater was used; similar to the high saline groundwater found at the 350m level at Aespoe HRL and at the Feature A site. The results of batch experiments show that the sorption of the tracers increase in the order Na + in the order of (4-30)x10 -6 m 3 /kg and for Cs + in the range of (I-400)x10 -3 m 3 /kg. The variations in sorption coefficients are due to differences in the composition of the geological material, contact time and particle size. Sorption is generally stronger for the Aespoe-diorite than for the fine-grained granite which is explained by the much higher concentration of biotite in Aespoe diorite than in fine-grained granite. In the altered material the biotite has been transformed to chlorite and a lower sorptivity is shown for those material compared to the fresh diorite and granite, respectively. Attempts to explain the sorption and desorption results to a surface sorption - diffusion model are presented. The diffusion results show that the tracers were retarded in the same order as was expected from the measured batch sorption coefficients. Furthermore, the largest size fraction was the most representative when comparing batch sorption coefficients with sorption coefficients evaluated from the

  3. Sorption of radioiodine in organo-clays and -soils

    International Nuclear Information System (INIS)

    Bors, J.

    1990-01-01

    In the framework of investigations on the sorption of radioiodine to natural and artificially altered soil components, a number of clay minerals and natural soils were treated with quaternary alkylammonium ions to replace the exchangeable metal cations. With help of batch experiments the resulting organo-clays were tested with respect to their sorption capability of radioiodine quantified by the distribution ratio (R D -value). Treatment of bentonite, vermiculite and cretaceous clay as well as of samples from natural horizons of chernozem soil with hexadecylpyridinium (HDPY + ) and benzethonium (BE + ) exhibited sorptions rates and amounts, which are several orders of magnitude higher than those of the respective untreated samples. Moderate increases of the R D -values were found after cation exchange with hexadecyltrimethylammonium (HDTMA + ), while the applications of trimethylphenylammonium (TMPA + ) and tetramethylammonium (TMA + ) were ineffective. Considerable sorption of radioiodine was observed with the commercially available Bentone. (orig.)

  4. Sorption of radioiodine in organo-clays and -soils

    Energy Technology Data Exchange (ETDEWEB)

    Bors, J. (Niedersaechsisches Inst. fuer Radiooekologie, Hannover (Germany, F.R.))

    1990-01-01

    In the framework of investigations on the sorption of radioiodine to natural and artificially altered soil components, a number of clay minerals and natural soils were treated with quaternary alkylammonium ions to replace the exchangeable metal cations. With help of batch experiments the resulting organo-clays were tested with respect to their sorption capability of radioiodine quantified by the distribution ratio (R{sub D}-value). Treatment of bentonite, vermiculite and cretaceous clay as well as of samples from natural horizons of chernozem soil with hexadecylpyridinium (HDPY{sup +}) and benzethonium (BE{sup +}) exhibited sorptions rates and amounts, which are several orders of magnitude higher than those of the respective untreated samples. Moderate increases of the R{sub D}-values were found after cation exchange with hexadecyltrimethylammonium (HDTMA{sup +}), while the applications of trimethylphenylammonium (TMPA{sup +}) and tetramethylammonium (TMA{sup +}) were ineffective. Considerable sorption of radioiodine was observed with the commercially available Bentone. (orig.).

  5. Transformation and sorption of illicit drug biomarkers in sewer biofilms

    DEFF Research Database (Denmark)

    Ramin, Pedram; Brock, Andreas Libonati; Causanilles Llanes, Ana

    2017-01-01

    , 16 drug biomarkers were selected, including the major human metabolites of mephedrone, methadone, cocaine, heroin, codeine and tetrahydrocannabinol (THC). Transformation and sorption of these substances were assessed in targeted batch experiments using laboratory-scale biofilm reactors operated under...

  6. Isothermal, kinetic and thermodynamic studies on basic dye sorption ...

    African Journals Online (AJOL)

    Isothermal, kinetic and thermodynamic studies on basic dye sorption onto tartaric acid esterified wheat straw. ... African Journal of Biotechnology ... esterified wheat straw (EWS), was originally prepared by solid phase thermochemistry method.

  7. Isothermal, kinetic and thermodynamic studies on basic dye sorption ...

    African Journals Online (AJOL)

    PRECIOUS

    2009-12-15

    Dec 15, 2009 ... The isothermal data correlated with the Langmuir model better than the. Freundlich model. ... there were two intra-particle diffusion steps in the dye sorption processes. .... rated monolayer of sorbate molecule on the sorbent.

  8. Sorption and desorption of insecticides in Brazilian soils

    International Nuclear Information System (INIS)

    Luchini, L.C.; Lord, K.A.; Ruegg, E.F.

    1980-01-01

    The sorption from aqueous solution of ten Brazilian soil types of four organochlorine, two organophosphorus and one carbamate insecticide was determined in the laboratory using gas chromatographic and radiometric techniques. Measurements showed that soils richest in organic matter, sorbed all substances except aldrin more strongly than the other soils. DDT was the most and aldrin the least sorbed organochlorine pesticide, being dieldrin sorbed two to four times more strongly than aldrin. Sorption of lindane varied in different soils. The organophosphate insecticides malathion and parathion were strongly sorbed in the soils richest in organic matter and weakly sorbed in the poorest soils heing moderately sorbed by the other soils. Sorption of carbaryl by all soils is small. Lindane was desorbed from the soil richest in organic matter and the extent of desorption was dependent on the sorption time. (Author) [pt

  9. Sorption of 237Pu by the diatom Asterionella formosa

    International Nuclear Information System (INIS)

    Conway, H.L.; Wahlgren, M.A.; Peterson, N.; Nelson, D.M.

    1976-01-01

    Knowledge of the behavior of the man-made radionuclide plutonium within aquatic environments is of fundamental importance in assessing its potential hazards and ecological impact. The sorption of plutonium by phytoplankton and other algae is the dominant factor in the biological transport of plutonium in the aquatic environment, and it has been suggested that sorption by phytoplankton may be responsible for the seasonal loss of plutonium from the epilimnion of Lake Michigan. A unialgal diatom culture was spiked with 237 Pu tracer solution in an attempt to simulate the behavior of fallout plutonium observed in field studies. The results were encouraging in that the 237 Pu in the filtered lake water medium exhibited strongly anionic properties similar to fallout plutonium in Lake Michigan, with limited sorption on container walls. The purpose of the present study was to extend the investigations of the sorption of plutonium by phytoplankton in a controlled environment using continuous culture techniques

  10. Copper foliar sorption: study of cuticular uptake and penetration

    International Nuclear Information System (INIS)

    Chamel, Andre; Bougie, Bernadette

    1977-01-01

    Results show that copper is easily retained by enzymatically isolated cuticles from pear leaves discs. The sorption is very rapid during the first hour, then progressively slower with increasing time. Upper and lower cuticles exhibit the same sorption when immersed, but the sorption by the upper internal surface is greater than that by the external surface. Sorption depends on the dates of sampling of the leaves and vegetal species. The variation of the process with concentrations is hyperbolic. The retained copper may be partially exchanged: from 16 to 95% after 24 hours of exchange in a cupric solution, as the Cu concentration increases from 10 -6 to 10 -2 M. The penetration of copper through astomatous cuticular discs is extremely reduced if there is pure water in the receiver unit [fr

  11. Effects of sorption hysteresis on radionuclide releases from waste packages

    International Nuclear Information System (INIS)

    Barney, G.S.; Reed, D.T.

    1985-01-01

    A one-dimensional, numerical transport model was used to calculate radionuclide releases from waste packages emplaced in a nuclear waste repository in basalt. The model incorporates both sorption and desorption isotherm parameters measured previously for sorption of key radionuclides on the packing material component of the waste package. Sorption hysteresis as described by these isotherms lowered releases of some radionuclides by as much as two orders of magnitude. Radionuclides that have low molar inventories (relative to uranium), high solubility, and strongly sorbed, are most affected by sorption hysteresis. In these cases, almost the entire radionuclide inventory is sorbed on the packing material. The model can be used to help optimize the thickness of the packing material layer by comparing release rate versus packing material thickness curves with Nuclear Regulatory Commission (NRC) and Environmental Protection Agency (EPA) release limits

  12. Diffusion and sorption on hardened cement pastes - experiments and modelling results

    Energy Technology Data Exchange (ETDEWEB)

    Jakob, A.; Sarott, F.-A.; Spieler, P.

    1999-08-01

    Large parts of repositories for low and intermediate level radioactive waste consist of cementitious materials. Radionuclides are transported by diffusion in the cement matrix or, in case of fractured or highly permeable cement, by advection and dispersion. In this work we aim at a mechanistic understanding of diffusion processes of some reactive tracers. On the laboratory scale, ten through-diffusion experiments were performed to study these processes for Cl{sup -}, I{sup -}, Cs{sup +} and Ni{sup 2+} ions in a Sulphate Resisting Portland Cement (SRPC) equilibrated with an artificial pore water. Some of the experiments continued up to nearly three years with daily measurements. In all the experiments, a cement disk initially saturated with an artificial pore water was exposed on one side to a highly diluted solution containing the species of interest. On the second side, a near-zero concentration boundary was maintained to drive through-diffusion of the tracer. The changes of concentrations on both sides of the samples were monitored, allowing careful mass balances. From these data, values of the diffusive flux and the mass of tracer taken up by the cementitious material were determined as a function of time. In the subsequent modelling, the time histories of these tracer breakthroughs were fitted using five different models. The simplest model neglects all retarding mechanisms except pure diffusion. More complex models either account for instantaneous equilibrium sorption in form of linear or non-linear (Freundlich) sorption or for first-order sorption kinetics where the forward reaction may be linear or non-linear according to the Freundlich isotherm, while the back-reaction is linear. Hence, the analysis allows the extraction of the diffusion coefficient and parameter values for the sorption isotherm or rate-constants for sorption and desorption. The fits to the experimental data were carried out by an automated Marquardt-Levenberg procedure yielding error

  13. Understanding mechanisms to predict and optimize biochar for agrochemical sorption

    Science.gov (United States)

    Hall, Kathleen; Gámiz, Beatriz; Cox, Lucia; Spokas, Kurt; Koskinen, William

    2017-04-01

    The ability of biochars to bind various organic compounds has been widely studied due to the potential effects on pesticide fate in soil and interest in the adoption of biochar as a "low-cost" filter material. However, the sorptive behaviors of biochars are extremely variable and much of the reported data is limited to specific biochar-chemical interactions. The lack of knowledge regarding biochar sorption mechanisms limits our current ability to predict and optimize biochar's use. This work unveils mechanistic drivers of organic pesticide sorption on biochars through targeted alteration of biochar surface chemistry. Changes in the quantity and type of functional groups on biochars and other black carbon materials were achieved through treatments with H2O2, and CO2, and characterized using Fourier transform infrared spectroscopy and scanning electron microscope (SEM/EDX). The sorption capacities of these treated biochars were subsequently measured to evaluate the effects of different surface moieties on the binding of target herbicides cyhalofop acid ((R)-2-[4-(4-cyano-2-fluorophenoxy)phenoxy]propionic acid) and clomazone (2-[(2-chlorophenyl)methyl]-4,4-dimethyl-1,2-oxazolidin-3-one). Sorption of both herbicides on the studied biochars increased following H2O2 activation; however, the influence of the H2O2 activation on sorption was more pronounced for cyhalofop acid (pKa = 3.9) than clomazone, which is non-ionizable. Increased cyhalofop acid sorption on H2O2 treated biochars can be attributed to the increase in oxygen containing functional groups as well as the decrease in biochar pH. In contrast, CO2 activation reduced the sorption of cyhalofop acid compared to untreated biochar. FTIR data suggest the reduced sorption on CO2 -treated biochar was due to the removal of surface carboxyl groups, further supporting the role of specific functionality in the sorption of ionizable herbicides. Results from this work offer insight into the mechanisms of sorption and

  14. Kinetics of the sorption of triterpene saponin by hypercrosslinked polystyrene

    Science.gov (United States)

    Mironenko, N. V.; Brezhneva, T. A.; Selemenev, V. F.

    2013-03-01

    The kinetics of sorption of triterpene saponin by the polymer sorbent NM-200 is considered. The influence of the surface activity of glycoside on the rate of formation and structure of the adsorption layer on the sorbent's surface is established. The rate-determining step of sorption is found to be diffusion into the sorbent grain. The value of the activation energy demonstrates the determining role of dispersion forces in the interaction between triterpene saponin and the polymer sorbent MN-200.

  15. Further developments of the RES3T sorption database

    International Nuclear Information System (INIS)

    Brendler, V.

    2002-01-01

    RES 3 T - the Rossendorf expert system for surface and sorption thermodynamics currently under development has been expanded towards the provision of comprehensive sorption data sets suitable for complex natural systems of rocks and soils. Also a statistical evaluation of the available SCM (surface complexation model) data is now implemented. Finally, a normalization of SCM parameters to a standard site density has been incorporated. (orig.)

  16. Sorption heat engines: simple inanimate negative entropy generators

    OpenAIRE

    Muller, Anthonie W. J.; Schulze-Makuch, Dirk

    2005-01-01

    The name 'sorption heat engines' is proposed for simple negative entropy generators that are driven by thermal cycling and work on alternating adsorption and desorption. These generators are in general not explicitly recognized as heat engines. Their mechanism is applicable to the fields of engineering, physics, chemistry, geology, and biology, in particular the origin of life. Four kinds of sorption heat engines are distinguished depending on the occurrence of changes in the adsorbent or ads...

  17. Sorption Properties of Steam Treated Wood and Plant Fibres

    DEFF Research Database (Denmark)

    Hoffmeyer, Preben; Jensen, Signe Kamp; Jones, Dennis

    2003-01-01

    temperatures the behaviour was different for low/medium RH and high RH. For low/medium range RH (.... This behaviour corresponds to the reduction of the number of primary sorption sites on e.g. hemicellulose. For high range RH (> ca. 85 %) two additional mechanisms may have been active. One is the capillary sorption in micropores created as a result of the thermal degradation of cell wall matter. A second...

  18. Sorption Characteristics of 137Cs and 90Sr into Rembang and Sumedang Soils

    Directory of Open Access Journals (Sweden)

    Budi Setiawan

    2016-12-01

    Full Text Available In order to understand the sorption behavior of 137Cs and 90Sr into soil sample from Rembang and Subang, it is important to estimate the effect of contact time, ionic strength and concentration of metal ion in the solution. For this reason, the interaction of 137Cs and 90Sr with soil sample has been examined. The study performed at trace concentration (~10-8 M of CsCl and SrCl2, and batch method was used. NaCl has been selected as a representative of the ionic strength with 0.1; 0.5 and 1.0 M concentrations. Concentration of 10-8~10-4 M CsCl and SrCl2 were used for study the effect of Cs and Sr concentrations in solution. Apparent distribution coefficient was used to predict the sorption behavior. The sorption equilibrium of 137Cs and 90Sr into soil was attained after 5 days contacted with Kd value around 3300-4200 mL/g, where Kd was defined as the ratio of number of radionuclide activity absorbed in solid phase per-unit mass to the number of radionuclide activity remains is solution per-unit volume. Presence of NaCl as background salt in the solution affected Kd values due to competition among metal ions into soil samples. Increase of Cs or Sr concentration in solution made Kd value decreased drastically. This information is expected could provide an important input for the planning and design of radioactive waste disposal system in Java Island in the future.

  19. Development of autoradiographic method for measuring sorption of radionuclides on natural fracture surfaces

    International Nuclear Information System (INIS)

    Muuronen, S.

    1983-11-01

    On the basis of positive results about sorption of radionuclides in rock thin sections an autoradiographic method applicable for measurement sorption of radionuclides on rough rock surfaces was developed. There is no method available because 1) a plane film cannot be used because due to the roughness of rock surfaces 2) rock samples used in this investigation cannot be studied with microscopes and 3) autoradiogram cannot be studied fixed on the surface of a rock sample because the colours of the minerals in the sample will interfere with the interpretation. This report discusses experimental work done to find an useful proedure. In the development of the method main emphasis was put on investigation of the following steps: 1) preparation of the sample for equilibration and spiking; 2) properties of the covering paint for the rock surface and 3) testing of autoradiographic methods using different nuclear emulsions. As the result of these experiments promising autoradiograms with gel emulsion for sawed rock surfaces and with stripping film for rough rock surfaces were obtained. The mineralogic disribution of sorbed activity is easily seen in autoradiograms. Much work must still be done to get reliable quantitative information from autoradiograms. For developing of the autoradiographic method sawed plane rock samples of quartz feldspar intergrowth, pegmatite and limestone were used. In addition core samples of tonalite and mica gneiss from Olkiluoto were utilized. The distribution coefficients (Ksub(a)) obtained for cesium were 560 x 10 -4 and 620 x 10 -4 m 3 /m 2 for tonalite and mica gneiss, respectively. The results are little higher but of the same order of magnitude as obtained by the autoradiographic method using rock thin sections and by the batch method using crused samples. The natural fracture surface sorption study is a logical step in determining the scaling factor from laboratory to field studies. Field data will be needed to determine whether laboratory

  20. Sorption behavior of europium(III) and curium(III) on the cell surfaces of microorganisms

    International Nuclear Information System (INIS)

    Ozaki, T.; Kimura, T.; Ohnuki, T.; Yoshida, Z.; Gillow, J.B.; Francis, A.J.

    2004-01-01

    We investigated the association of europium(III) and curium(III) with the microorganisms Chlorella vulgaris, Bacillus subtilis, Pseudomonas fluorescens, Halomonas sp., Halobacterium salinarum, and Halobacterium halobium. We determined the kinetics and distribution coefficients (K d ) for Eu(III) and Cm(III) sorption at pH 3-5 by batch experiments, and evaluated the number of water molecules in the inner-sphere (N H 2 O ) and the degree of strength of ligand field (R E/M ) for Eu(III) by time-resolved laser-induced fluorescence spectroscopy (TRLFS). Exudates from C. vulgaris, Halomonas sp., and H. halobium had an affinity for Eu(III) and Cm(III). The log K d of Eu(III) and Cm(III) showed that their sorption was not fully due to the exchange with three protons on the functional groups on cell surfaces. The halophilic microorganisms (Halomonas sp., Halobacterium salinarum, H. halobium) showed almost no pH dependence in log K d , indicating that an exchange with Na + on the functional groups was involved in their sorption. The ΔN H 2 O (= 9 - N H 2 O ) for Eu(III) on C. vulgaris was 1-3, while that for the other microorganisms was over 3, demonstrating that the coordination of Eu(III) with C. vulgaris was predominantly an outer-spherical process. The R E/M for Eu(III) on halophilic microorganisms was 2.5-5, while that for non-halophilic ones was 1-2.5. This finding suggests that the coordination environment of Eu(III) on the halophilic microorganisms is more complicated than that on the other three non-halophilic ones. (orig.)

  1. Sorption behavior of europium(III) and curium(III) on the cell surfaces of microorganisms

    Energy Technology Data Exchange (ETDEWEB)

    Ozaki, T.; Kimura, T.; Ohnuki, T.; Yoshida, Z. [Advanced Science Research Center, Japan Atomic Energy Research Inst., Ibaraki (Japan); Gillow, J.B.; Francis, A.J. [Environmental Sciences Dept., Brookhaven National Lab., Upton, NY (United States)

    2004-07-01

    We investigated the association of europium(III) and curium(III) with the microorganisms Chlorella vulgaris, Bacillus subtilis, Pseudomonas fluorescens, Halomonas sp., Halobacterium salinarum, and Halobacterium halobium. We determined the kinetics and distribution coefficients (K{sub d}) for Eu(III) and Cm(III) sorption at pH 3-5 by batch experiments, and evaluated the number of water molecules in the inner-sphere (N{sub H{sub 2}O}) and the degree of strength of ligand field (R{sub E/M}) for Eu(III) by time-resolved laser-induced fluorescence spectroscopy (TRLFS). Exudates from C. vulgaris, Halomonas sp., and H. halobium had an affinity for Eu(III) and Cm(III). The log K{sub d} of Eu(III) and Cm(III) showed that their sorption was not fully due to the exchange with three protons on the functional groups on cell surfaces. The halophilic microorganisms (Halomonas sp., Halobacterium salinarum, H. halobium) showed almost no pH dependence in log K{sub d}, indicating that an exchange with Na{sup +} on the functional groups was involved in their sorption. The {delta}N{sub H{sub 2}O} (= 9 - N{sub H{sub 2}O}) for Eu(III) on C. vulgaris was 1-3, while that for the other microorganisms was over 3, demonstrating that the coordination of Eu(III) with C. vulgaris was predominantly an outer-spherical process. The R{sub E/M} for Eu(III) on halophilic microorganisms was 2.5-5, while that for non-halophilic ones was 1-2.5. This finding suggests that the coordination environment of Eu(III) on the halophilic microorganisms is more complicated than that on the other three non-halophilic ones. (orig.)

  2. Characterization and radionuclides sorption of suspended particulate matters in freshwater according to their settling kinetics

    International Nuclear Information System (INIS)

    Brach-Papa, C.; Boyer, P.; Amielh, M.; Anselmet, F.

    2004-01-01

    In freshwater, the transfers of radionuclides depend both on exchanges between liquid and solid phases and on mass transfers between suspended matter and bottom sediment. Whereas the former ones depend on chemical processes (such as sorption/desorption, complexation, the latter ones are regulated by hydrological and sedimentary considerations (dispersion, erosion, deposit closely related to the interactions between flow, suspended matter and bed sediment. Some of our previous studies highlight the need to consider the matter heterogeneity and its specific sediment dynamics to correctly report the inhomogeneity of fluxes in time and in space. These considerations lead us to develop experimental methods to distinguish the different matter classes, present in natural water, mainly according to their erosion threshold and settling kinetics. In this context, this paper presents the experimental protocol TALISMEN to characterize a natural bulk suspension according the identification of its main settling kinetics groups. In a first step, this identification is achieved by the use of a settling tank, that allows the monitoring of the suspended solid concentration at various depths, combined to a vertical mono-dimensional settling model applying a multi-class approach. In a second step, the particle groups are isolated and their physico-chemical properties are determined ( i.e mineral composition, specific surface area, particulate organic carbon, in order to fully characterized them. In a last one, the sorption property of each group toward radionuclides is determined by the measurements of its distribution coefficients (Kd). The results confirm the interest to consider these heterogeneities for the modelling of the radionuclides transfer in freshwater. From one group to other, these heterogeneities appear at two levels: 1) their sediment dynamics and 2) their radionuclides sorption properties. These conclusions can be equally applying to others xenobiotics as heavy metals

  3. Status of radionuclide sorption-desorption studies performed by the WRIT program

    International Nuclear Information System (INIS)

    Serne, R.J.; Relyea, J.F.

    1981-01-01

    This paper focuses on interactions between dissolved radionuclides in groundwater and rocks and sediments away from the nearfield repository. Two approaches were used to study the primary mechanism, adsorption-desorption. Empirical studies rely on distribution coefficient measurements, and mechanism studies strive to identify, differentiate, and quantify the processes that control nuclide retardation. The status of sorption mechanism studies is discussed, with emphasis on delineating the usefulness of ideal ion-exchange, site-binding electrical double-layer, and redox-controlled sorption constructs. Since studies to date show greater potential for site-binding electrical double-layer models, future efforts will concentrate on this construct. Laboratory studies are discussed which corroborate the importance of redox reactions in causing nuclide retardation for multivalent elements, such as Tc, Np, Pu, and U. Results suggest that both solution-mediated reduction, such as the Fe(II)-Fe(III) couple, and solid-solution heterogeneous reduction reactions, such as reduction of solution Pu(VI) at the mineral surface by structural Fe(II), occur. Coupled microscopy, microprobe, and autoradiography studies have determined actual sorption sites for radionuclides on polymineralic rocks. The studies show that it is possible for minor phases to completely dominate the mass of radionuclides adsorbed. The most active minerals are typically alternation products (clays and zeolites). Several exercises are discussed which rank radionuclides according to their potential dose hazards. In each of the analyses discussed, the top four radionuclides are I, Tc, Np, and Ra. Other elements that rank high in potential hazards are Pu, U, Am, Th, Pb, Sn, Pd, and Se

  4. Effect of humic acid & bacterial exudates on sorption-desorption interactions of 90Sr with brucite.

    Science.gov (United States)

    Ashworth, Hollie; Abrahamsen-Mills, Liam; Bryan, Nick; Foster, Lynn; Lloyd, Jonathan R; Kellet, Simon; Heath, Sarah

    2018-05-18

    One of the nuclear fuel storage ponds at Sellafield (United Kingdom) is open to the air, and has contained a significant inventory of corroded magnox fuel and sludge for several decades. As a result, some fission products have also been released into solution. 90Sr is known to constitute a small mass of the radionuclides present in the pond, but due to its solubility and activity, it is at risk of challenging effluent discharge limits. The sludge is predominantly composed of brucite (Mg(OH)2), and organic molecules are known to be present in the pond liquor with occasional algal blooms restricting visibility. Understanding the chemical interactions of these components is important to inform ongoing sludge retrievals and effluent management. Additionally, interactions of radionuclides with organics at high pH will be an important consideration for the evolution of cementitious backfilled disposal sites in the UK. Batch sorption-desorption experiments were performed with brucite, 90Sr and natural organic matter (NOM) (humic acid (HA) and Pseudanabaena catenata cyanobacterial growth supernatant) in both binary and ternary systems at high pH. Ionic strength, pH and order of addition of components were varied. 90Sr was shown not to interact strongly with the bulk brucite surface in binary systems under pH conditions relevant to the pond. HA in both binary and ternary systems demonstrated a strong affinity for the brucite surface. Ternary systems containing HA demonstrated enhanced sorption of 90Sr at pH 11.5 and vice versa, likely via formation of strontium-humate complexes regardless of the order of addition of components. The distribution coefficients show HA sorption to be reversible at all pH values studied, and it appeared to control 90Sr behaviour at pH 11.5. Ternary systems containing cyanobacterial supernatant demonstrated a difference in 90Sr behaviour when the culture had been subjected to irradiation in the first stages of its growth.

  5. Moisture sorption isotherms and thermodynamic properties of bovine leather

    Science.gov (United States)

    Fakhfakh, Rihab; Mihoubi, Daoued; Kechaou, Nabil

    2018-04-01

    This study was aimed at the determination of bovine leather moisture sorption characteristics using a static gravimetric method at 30, 40, 50, 60 and 70 °C. The curves exhibit type II behaviour according to the BET classification. The sorption isotherms fitting by seven equations shows that GAB model is able to reproduce the equilibrium moisture content evolution with water activity for moisture range varying from 0.02 to 0.83 kg/kg d.b (0.9898 thermodynamic properties such as isosteric heat of sorption, sorption entropy, spreading pressure, net integral enthalpy and entropy. Net isosteric heat of sorption and differential entropy were evaluated through direct use of moisture isotherms by applying the Clausius-Clapeyron equation and used to investigate the enthalpy-entropy compensation theory. Both sorption enthalpy and entropy for desorption increase to a maximum with increasing moisture content, and then decrease sharply with rising moisture content. Adsorption enthalpy decreases with increasing moisture content. Whereas, adsorption entropy increases smoothly with increasing moisture content to a maximum of 6.29 J/K.mol. Spreading pressure increases with rising water activity. The net integral enthalpy seemed to decrease and then increase to become asymptotic. The net integral entropy decreased with moisture content increase.

  6. Investigation of rare earths sorption from sulfuric- and hydrochloric media

    International Nuclear Information System (INIS)

    Nikonov, V.N.; Mikhlin, E.B.; Norina, T.M.; Afonina, T.A.

    1978-01-01

    A rate of equilibrium attainment has been studied during REE sorption from sulfuric and hydrochloric acid solutions and pulps. It has been shown that equilibrium upon sorption from hydrochloric acid solutions is attained faster than from sulfuric acid solutions. Equilibrium upon sorption from pulps is attained considerably slower than upon sorption from solutions. In all cases REM of cerium subgroup are sorbed better. An effect has been studied of the medium acidity on sorbability of REM and elements of iron and calcium impurities. It has been established that sorbability of these elements decreases with increasing acid concentration. Selectivity of REM sorption from sulfuric acid solutions decreases with a rise in H 2 SO 4 concentration in the solution. For hydrochloric acid solutions it remains constant in a wide range of HCl concentrations. Sorption leaching of REM from concentrates and cakes of sulfuric and hydrochloric acids in the presence of KU-2 leads to high technical and economic indexes: extraction with respect to the total amount of REM and yttrium into a commercial product is 76-86% for sulfuric acid solutions and 81-90% for hydrochloric solutions

  7. Modelling of a diffusion-sorption experiment on sandstone

    International Nuclear Information System (INIS)

    Smith, P.A.

    1989-11-01

    The results of a diffusion-sorption experiment on a sample of Darley Dale sandstone, using simulated groundwater spiked with a mixture of 125 I, 85 Sr and 137 Cs, are modelled by a one-dimensional porous medium approach in which sorption is described by Freundlich isotherms. The governing equations are solved analytically for the special case of a linear isotherm, and numerically using the computer code RANCHDIFF for non-linear isotherms. A set of time-dependent, ordinary differential equations is obtained using the Lagrange interpolation technique and integrated by Gear's variable order predictor-corrector method. It is shown that the sorption behaviour of 85 Sr can be modelled successfully by a linear isotherm, using a sorption parameter consistent with batch-sorption tests. The behaviour of 137 Cs may be modelled by a non-linear isotherm, but the amount of 137 Cs sorbed is less than that anticipated from batch-sorption tests. 125 I is assumed to be non-sorbing and is used to determine the porosity of the sandstone. (author) 10 figs., 4 tabs., 6 refs

  8. The sorption of silver by poorly crystallized manganese oxides

    Science.gov (United States)

    Anderson, B.J.; Jenne, E.A.; Chao, T.T.

    1973-01-01

    The sorption of silver by poorly crystallized manganese oxides was studied using synthesized samples of three members of the manganous manganite (birnessite) group, of different chemical composition and crystallinity, and a poorly organized ??-MnO2. All four oxides sorbed significant quantities of silver. The manganous manganites showed the greatest sorption (up to 0.5 moles silver/mole MnOx at pH 7) while the ??-MnO2 showed the least (0.3 moles silver/ mole MnOx at pH 7). Sorption of silver was adequately described by the Langmuir equation over a considerable concentration range. The relationship failed at low pH values and high equilibrium silver concentrations. The sorption capacity showed a direct relationship with pH. However, the rate of increase of sorption capacity decreased at the higher pH values. Silver sorption maxima. were not directly related to surface area but appeared to vary with the amount of occluded sodium and potassium present in the manganese oxide. The important processes involved in the uptake of silver by the four poorly crystallized manganese oxides ara considered to be surface exchange for manganese, potassium and sodium as well as exchange for structural manganese, potassium and sodium. ?? 1973.

  9. Thermodynamic parameters and sorption of U(VI) on ACSD

    International Nuclear Information System (INIS)

    Donat, R.; Cilgi, G.K.; Cetisli, H.; Aytas, S.

    2009-01-01

    This paper discusses the sorption properties for U(VI) by alginate coated CaSO 4 x 2H 2 O sepiolite and calcined diatomite earth (Kieselguhr) (ACSD). The removal of U(VI) from aqueous solution by sorption onto ACSF in a single component system with various contact times, pH, temperatures, and initial concentrations of U(VI) was investigated. The sorption patterns of uranium on the composite adsorbent followed the Langmuir, Freundlich and Dubinin-Radushkhevic (D-R) isotherms. The Freundlich, Langmuir, and D-R models have been applied and the data correlated well with Freundlich model and that the sorption was physical in nature (sorption energy, E a = 17.05 kJ/mol). The thermodynamic parameters such as variation of enthalpy ΔH, variation of entropy ΔS and variation of Gibbs free energy ΔG were calculated from the slope and intercept of lnK 0 vs. 1/T plots. Thermodynamic parameters (ΔH ads = 31.83 kJ/mol, ΔS ads = 167 J/mol x K, ΔGdeg ads (293.15 K) = -17.94 kJ/mol) showed the endothermic heat of sorption and the feasibility of the process. The thermodynamics of U(VI) ion/ACSD system indicates the spontaneous and endothermic nature of the process. It was noted that an increase in temperature resulted in a higher uranium loading per unit weight of the adsorbent. (author)

  10. Experimental determination of sorption in fractured flow systems

    Science.gov (United States)

    Zimmerman, Mitchell D.; Bennett, Philip C.; Sharp, John M.; Choi, Wan-Joo

    2002-09-01

    Fracture "skins" are alteration zones on fracture surfaces created by a variety of biological, chemical, and physical processes. Skins increase surface area, where sorption occurs, compared to the unaltered rock matrix. This study examines the sorption of organic solutes on altered fracture surfaces in an experimental fracture-flow apparatus. Fracture skins containing abundant metal oxides, clays, and organic material from the Breathitt Formation (Kentucky, USA) were collected in a manner such that skin surface integrity was maintained. The samples were reassembled in the lab in a flow-through apparatus that simulated ˜2.7 m of a linear fracture "conduit." A dual-tracer injection scheme was utilized with the sorbing or reactive tracer compared to a non-reactive tracer (chloride) injected simultaneously. Sorption was assessed from the ratio of the first temporal moments of the breakthrough curves and from the loss of reactive tracer mass and evaluated as a function of flow velocity and solute type. The breakthrough curves suggest dual-flow regimes in the fracture with both sorbing and non-sorbing flow fields. Significant sorption occurs for the reactive components, and sorption increased with decreasing flow rate and decreasing compound solubility. Based on moment analysis, however, there was little retardation of the center of solute mass. These data suggest that non-equilibrium sorption processes dominate and that slow desorption and boundary layer diffusion cause extensive tailing in the breakthrough curves.

  11. Correlational study between sorption and goo apparent organoclays

    International Nuclear Information System (INIS)

    Silva, D.L.; Silva, M.R.O.; Ferreira, H.S.; Brasileiro, C.T.

    2016-01-01

    The sorption of surfactants in bentonite clay can occur through the mechanism of adsorption and absorption, this being a very supple phenomenon according clay and surfactant utilized. Thus the more surfactant sorbed at the organoclay it becomes, and can be used in various applications, including in oil drilling fluid. This study aimed to correlate the sorption of surfactants with the rheological properties of non-aqueous fluids (oil base). In organophilization process was used Bentongel clay which had its concentration varied from 3.16 to 7.16% by weight of clay. It was used to organophilization an ionic surfactant Praepagem WB with 75% of active matter, where its concentration ranged from 127-181 mEq. After organophilizated the clays were filtered, dried in an oven for 48 hours and passed in ABNT sieve No. 200, to be so characterized. Sorption was calculated from mathematical equations. Non-aqueous fluids were prepared according to standard Petrobras (EP-1EP-00023A) for rheological testing. Correlating the sorption of surfactant, and the rheological properties of non-aqueous fluid, obtained satisfactory results where observed through the scatter plots there is a strong correlation between the variables sorption and apparent viscosity, it should also be noted that the viscosity is a variable which increases with an increase in sorption, confirming that the surfactant concentration influences the viscosity. (author)

  12. Study of the temperature influence during the uranium (Vi) sorption on surface of ZrP2O7 in presence of oxalic and salicylic acid

    International Nuclear Information System (INIS)

    Garcia G, N.

    2013-01-01

    This work studies the effect of temperature on the uranium (Vi) sorption onto zirconium diphosphate in the presence of organic acids (oxalic and salicylic acids). Zirconium diphosphate was synthesized by a chemical condensation reaction and characterized using several analytical techniques, in order to check its purity. This point is very important because the presence of any impurities or secondary phases may interfere with the hydration and sorption process. Prior to the sorption experiments, three batches of zirconium diphosphate were pre-equilibrated with NaClO 4 , oxalic acid or salicylic acid solutions. The hydrated solids were washed and dried and then again characterized in order to study the interactions between organic acids and zirconium diphosphate surface. Uranium sorption onto zirconium diphosphate (pre-equilibrated with NaClO 4 , oxalic acid and salicylic acid solutions) was investigated as a function of ph, organic acid and temperature (20, 40 y 60 grades C). Thermodynamic parameters for the sorption reactions (enthalpy change, entropy change and Gibbs free energy change) were determined from temperature dependence of distribution coefficient by using the Vant Hoff equation. Solids characterization after hydration shows that exist an interaction between organic acids and ZrP 2 O 7 . This fact was confirmed with the microcalorimetry study, the reaction heat for hydration of zirconium diphosphate in NaClO 4 solution was exothermic (-269.59 mJ) and for hydration of zirconium diphosphate in oxalic acid solution was endothermic (53.64 mJ). The experimental results showed important differences in the sorption mechanisms for the reaction of Uranium with ZrP 2 O 7 in the presence and absence of organic acids. For the zirconium diphosphate hydrated with oxalic acid, the sorption percentage was 50% from lowest ph values. For the zirconium diphosphate hydrated with salicylic acid, the initial concentration of uranium was 6 x 10 -4 M and a percentage of 10% was

  13. Sorption and diffusion of FE(II) in bentonite

    International Nuclear Information System (INIS)

    Muurinen, A.; Tournassat, C.; Hadi, J.; Greneche, J.-M.

    2014-02-01

    The iron in the engineering barrier system of a nuclear waste repository interacts via the corrosion process with the swelling clay intended as the buffer material. This interaction may affect the sealing properties of the clay. In the case of iron-bentonite interaction, redox reactions, dissolution/precipitation, the diffusion and sorption are coupled together. In a combined study different processes are difficult to distinguish from each other, and more specific studies are needed for the separate processes. In particular, there is a need for well-controlled diffusion and sorption experiments where iron is kept as Fe(II). In this project, sorption and diffusion of Fe(II) in bentonite have been studied. The experiments were carried out under low-oxygen conditions in an anaerobic glove-box. The radioactive isotope ( 55 Fe) was used as a tracer in the experiments. The sorption experiments were carried out with two batches of purified MX-80 bentonite. One was purified at Bureau de Recherches Geologiques et Minieres, French Geological Survey (BRGM) and the other one at VTT Technical Research Centre of Finland (VTT). Experiments were also carried out with synthetic smectite, which did not include iron, which was prepared at LMPC (ENSC, F 68093 Mulhouse, France). The sorption experiments were carried out in 0.3 M and 0.05 M NaCl solutions as a function of pH, and in 0.3 M NaCl solution buffered at pH 5 as a function of added Fe(II) concentration. The separation of bentonite and solution at the end of the sorption experiment was carried out in the early phase by centrifuging only. In the later phase, ultrafiltering was added in order to improve the separation. The diffusion experiments were carried out in compacted samples prepared from MX-80 purified at VTT and saturated with 0.3 M NaCl at pH 8 and 5. A non-steady-state diffusion experiment method, where the tracer was introduced as an impulse source between two bentonite plugs was used in the measurements

  14. Sorption and diffusion of FE(II) in bentonite

    Energy Technology Data Exchange (ETDEWEB)

    Muurinen, A. [VTT Technical Research Centre of Finland, Espoo (Finland); Tournassat, C.; Hadi, J. [BRGM, Orleans (France); Greneche, J.-M. [LPCE, Le Mans (France)

    2014-02-15

    The iron in the engineering barrier system of a nuclear waste repository interacts via the corrosion process with the swelling clay intended as the buffer material. This interaction may affect the sealing properties of the clay. In the case of iron-bentonite interaction, redox reactions, dissolution/precipitation, the diffusion and sorption are coupled together. In a combined study different processes are difficult to distinguish from each other, and more specific studies are needed for the separate processes. In particular, there is a need for well-controlled diffusion and sorption experiments where iron is kept as Fe(II). In this project, sorption and diffusion of Fe(II) in bentonite have been studied. The experiments were carried out under low-oxygen conditions in an anaerobic glove-box. The radioactive isotope ({sup 55}Fe) was used as a tracer in the experiments. The sorption experiments were carried out with two batches of purified MX-80 bentonite. One was purified at Bureau de Recherches Geologiques et Minieres, French Geological Survey (BRGM) and the other one at VTT Technical Research Centre of Finland (VTT). Experiments were also carried out with synthetic smectite, which did not include iron, which was prepared at LMPC (ENSC, F 68093 Mulhouse, France). The sorption experiments were carried out in 0.3 M and 0.05 M NaCl solutions as a function of pH, and in 0.3 M NaCl solution buffered at pH 5 as a function of added Fe(II) concentration. The separation of bentonite and solution at the end of the sorption experiment was carried out in the early phase by centrifuging only. In the later phase, ultrafiltering was added in order to improve the separation. The diffusion experiments were carried out in compacted samples prepared from MX-80 purified at VTT and saturated with 0.3 M NaCl at pH 8 and 5. A non-steady-state diffusion experiment method, where the tracer was introduced as an impulse source between two bentonite plugs was used in the measurements

  15. Sorption of organic water pollutants on dead vegetable biomass; Sorption organischer Wasserschadstoffe an abgestorbene pflanzliche Biomasse

    Energy Technology Data Exchange (ETDEWEB)

    Kraeuter, A.

    2001-03-01

    Hemp-derived biological sorption agents were produced, and their physical, chemical and sorptive characteristics were tested in batch and filter tests. The experiments were accompanied by model calculations. In the natural state, the sorption agents had a kation exchange capacity of 0.1-0.3 mmol/g, modified sorption agents had about 2 mmol/g. Kationized hemp had values of 0.34 mmol/g and thermally modified hemp absorption agents absorbed more than 1.2 mmol/g of dichlorophenol. In the case of a liquid effluent from a textile dyeing plant, only a discoloration effect was achieved. The absorption agents can be regenerated, combusted or composted after use. [German] Im Rahmen dieser Arbeit wurden naturbelassene und modifizierte Billig-Biosorbentien aus Hanfschaeben zur Entfernung organischer Schadstoffe aus Waessern hergestellt und ihre physikalischen, chemischen und sorptiven Eigenschaften in Batch- und Filterversuchen untersucht. Wegen der Komplexheit des Systems ''Biosorption organischer Wasserschadstoffe'' wurden die ermittelten Sorptionsisothermen mit den Ansaetzen nach Langmuir und Freundlich beschrieben. Die Sorptionskinetik und das Durchbruchsverhalten wurde ebenfalls mit einfachen Ansaetzen modelliert. Naturbelassene Hanfschaeben erreichten Kationenaustauschkapazitaeten von 0,1-0,3 mmol/g, entsprechend modifizierte Hanfschaeben ca. 2 mmol/g. Kationisierte Hanfschaeben dagegen erreichten Anionenaustauschkapazitaeten von 0,34 mmol/g und thermisch modifizierte Hanfschaeben sorbierten bis ueber 1,2 mmol/g Dichlorphenol. Bei der Behandlung eines Abwassers aus einer Textilfaerberei beschraenkte sich die Reinigungsleistung der hergestellten Biosorbentien auf eine Entfaerbung. Nach Schadstoffbeladung koennen die Hanfschaeben regeneriert, thermisch verwertet oder kompostiert werden. (orig.)

  16. Quadrature formulas for Fourier coefficients

    KAUST Repository

    Bojanov, Borislav

    2009-09-01

    We consider quadrature formulas of high degree of precision for the computation of the Fourier coefficients in expansions of functions with respect to a system of orthogonal polynomials. In particular, we show the uniqueness of a multiple node formula for the Fourier-Tchebycheff coefficients given by Micchelli and Sharma and construct new Gaussian formulas for the Fourier coefficients of a function, based on the values of the function and its derivatives. © 2009 Elsevier B.V. All rights reserved.

  17. Coefficient Alpha: A Reliability Coefficient for the 21st Century?

    Science.gov (United States)

    Yang, Yanyun; Green, Samuel B.

    2011-01-01

    Coefficient alpha is almost universally applied to assess reliability of scales in psychology. We argue that researchers should consider alternatives to coefficient alpha. Our preference is for structural equation modeling (SEM) estimates of reliability because they are informative and allow for an empirical evaluation of the assumptions…

  18. Coefficient estimates of negative powers and inverse coefficients for ...

    Indian Academy of Sciences (India)

    and the inequality is sharp for the inverse of the Koebe function k(z) = z/(1 − z)2. An alternative approach to the inverse coefficient problem for functions in the class S has been investigated by Schaeffer and Spencer [27] and FitzGerald [6]. Although, the inverse coefficient problem for the class S has been completely solved ...

  19. Measuring of heat transfer coefficient

    DEFF Research Database (Denmark)

    Henningsen, Poul; Lindegren, Maria

    Subtask 3.4 Measuring of heat transfer coefficient Subtask 3.4.1 Design and setting up of tests to measure heat transfer coefficient Objective: Complementary testing methods together with the relevant experimental equipment are to be designed by the two partners involved in order to measure...... the heat transfer coefficient for a wide range of interface conditions in hot and warm forging processes. Subtask 3.4.2 Measurement of heat transfer coefficient The objective of subtask 3.4.2 is to determine heat transfer values for different interface conditions reflecting those typically operating in hot...

  20. Estimation of distribution coefficient for uranium in soil around a waste disposal site at Trombay

    International Nuclear Information System (INIS)

    Mishra, S.; Chaudhary, D.K.; Sandeep, P.; Pandit, G.G.

    2014-01-01

    Soil contamination arising from the disposed waste from industrial origin is of major concern now a days. There is a possibility of run off as well as Ieaching of contaminants from the sites to nearby aquatic bodies through rain water. Distribution coefficient, K d in soil is an important parameter to predict the migration of contaminants. However it requires precise measurement not only for the accurate prediction of contaminant transport but also for describing the sorption behavior in a particular environment. The variation of K d values for a radionuclide is due to differences in geochemical conditions, soil materials, nature of water and methods used for the measurements. For the present study soil samples have been collected near a waste disposal site at Trombay and the sorption of uranium has been studied by measuring the distribution coefficient (K d ) by laboratory batch method. In our earlier studies, we could notice substantial effect of ionic composition of ground water on the K d values of uranium. In this study we have used rain water as the sorption media and the measured K d value s were compared with previous values for different soil and water characteristics from different regions of India

  1. Application of simplified desorption method to sorption study. (2) Sorption of neptunium (V) on montmorillonite-based mixtures

    International Nuclear Information System (INIS)

    Kozai, Naofumi; Ohnuki, Toshihiko

    2013-01-01

    To elucidate the sorption behaviors of radionuclides in multi-mineral systems and the mutual effects of minerals on the sorption, this paper carried out the sorption and desorption experiments of neptunium(V) on montmorillonite-based two-mineral mixtures. The Np sorbed on montmorillonite at pH from 4 to 8 was desorbed with 1M KCl solutions, indicating that the sorption was cation exchange. The Np sorbed on apatite and calcite was nondesorbable with 1M KCl solutions, which is in harmony with the knowledge that Np forms strong complexes with the phosphate groups of apatite and the carbonate groups of calcite. This study utilized these clear distinguishes of the desorption behaviors for examining the two-mineral systems. In montmorillonite-apatite mixtures, the sorption on the montmorillonite was decreased and Np was accumulated on the apatite. In montmorillonite-calcite mixtures, the sorption on the montmorillonite was decreased due to the interference by the calcium and carbonate ions dissolved from calcite while no accumulation of Np to calcite was observed. (author)

  2. Vertical barriers with increased sorption capacities

    International Nuclear Information System (INIS)

    Bradl, H.B.

    1997-01-01

    Vertical barriers are commonly used for the containment of contaminated areas. Due to the very small permeability of the barrier material which is usually in the order of magnitude of 10-10 m/s or less the advective contaminant transport can be more or less neglected. Nevertheless, there will always be a diffusive contaminant transport through the barrier which is caused by the concentration gradient. Investigations have been made to increase the sorption capacity of the barrier material by adding substances such as organoclays, zeolites, inorganic oxides and fly ashes. The contaminants taken into account where heavy metals (Pb) and for organic contaminants Toluole and Phenantrene. The paper presents results of model calculations and experiments. As a result, barrier materials can be designed 'tailor-made' depending on the individual contaminant range of each site (e.g. landfills, gasworks etc.). The parameters relevant for construction such as rheological properties, compressive strength and permeability are not affected by the addition of the sorbents

  3. Characterization of nanoporous shales with gas sorption

    Science.gov (United States)

    Joewondo, N.; Prasad, M.

    2017-12-01

    The understanding of the fluid flow in porous media requires the knowledge of the pore system involved. Fluid flow in fine grained shales falls under different regime than transport regime in conventional reservoir due to the different average pore sizes in the two materials; the average pore diameter of conventional sandstones is on the micrometer scale, while of shales can be as small as several nanometers. Mercury intrusion porosimetry is normally used to characterize the pores of conventional reservoir, however with increasingly small pores, the injection pressure required to imbibe the pores becomes infinitely large due to surface tension. Characterization of pores can be expressed by a pore size distribution (PSD) plot, which reflects distribution of pore volume or surface area with respect to pore size. For the case of nanoporous materials, the surface area, which serves as the interface between the rock matrix and fluid, becomes increasingly large and important. Physisorption of gas has been extensively studied as a method of nanoporous solid characterization (particularly for the application of catalysis, metal organic frameworks, etc). The PSD is obtained by matching the experimental result to the calculated theoretical result (using Density Functional Theory (DFT), a quantum mechanics based modelling method for molecular scale interactions). We present the challenges and experimental result of Nitrogen and CO2 gas sorption on shales with various mineralogy and the interpreted PSD obtained by DFT method. Our result shows significant surface area contributed by the nanopores of shales, hence the importance of surface area measurements for the characterization of shales.

  4. Kinetic Study of Zn2+ and Cd2+ Ions Sorption by Ceric Oxide Powder

    International Nuclear Information System (INIS)

    Hassan, H.S.; Abd El-Rahman, K.M.; El Sayed, A.A.

    2008-01-01

    Ceric Oxide powder was chemically synthesized and characterized using infrared spectra and x-ray diffraction. The sorptive removal of Zinc and Cadmium ions from aqueous waste solution using synthetic ceric oxide powder was investigated using batch technique. Experiments were carried out as a function of ph, particle size, solute concentration and temperature. The uptake of zinc was found to be greater than that of cadmium. A comparison of kinetic models applied to the sorption process of each ion was evaluated for the pseudo first order, the pseudo second order, and homogeneous particle diffusion kinetic models, respectively. The results showed that both the pseudo second order and the homogeneous particle diffusion model (HPDM) were found to best correlate the experimental rate data. The numerical values of the rate constants and particle diffusion coefficients were determined from the graphical representation of the proposed models. Activation energy (Ε a ) and entropy (δ S * ) of activation for each sorption process were also calculated from the linearized form of Arrhenius equation

  5. Experimental methods for studying the diffusion of radioactive gases in solids. VII. Sorption method

    International Nuclear Information System (INIS)

    Bekman, I.N.

    1983-01-01

    The details of the use of a sorption method in the study of the diffusion of gasses and vapors labeled with radioactive tracers in solids have been considered. Three variants of diffusion systems, which permit the determination of the diffusion coefficient and the solubility constant of gases both from the increase in the amount of diffus