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Sample records for water desorption process

  1. Experimental study on desorption of soluble matter as influenced by cations in static water

    Directory of Open Access Journals (Sweden)

    Wen-sheng XU

    2015-10-01

    Full Text Available With variation of drainage basin environments, desorption of soluble matter has become one of the significant erosion processes in rivers. It has a considerable impact on flow and sediment transport, as well as processes of river bed deformation and landform evolution throughout a watershed. In this study, considering influences on sediment movement, especially on cohesive sediment transport, Ca2+ and H+ were chosen as characteristic ions of soluble matter, and the total desorption quantity of Ca2+ and pH value when the desorption equilibrium is reached were employed as two indexes representing the desorption of soluble matter. By means of an indoor experiment, desorption of soluble matter as influenced by cations in static water was investigated. The results show that the total desorption quantity of soluble matter increases with the initial cation concentration until a maximum desorption quantity value is obtained and maintained. The total desorption quantity of soluble matter depends on properties of the specific cations in static water, and the stronger the affinity is between the cation and sediment surface, the higher the total desorption quantity will be. Finally, a strong approximate linear relationship between desorption quantities for different kinds of soluble matters was obtained, which means that variation of pH values can accurately reflect the desorption results of soluble matter.

  2. Sorption and desorption of carbamazepine from water by smectite clays.

    Science.gov (United States)

    Zhang, Weihao; Ding, Yunjie; Boyd, Stephen A; Teppen, Brian J; Li, Hui

    2010-11-01

    Carbamazepine is a prescription anticonvulsant and mood stabilizing pharmaceutical administered to humans. Carbamazepine is persistent in the environment and frequently detected in water systems. In this study, sorption and desorption of carbamazepine from water was measured for smectite clays with the surface negative charges compensated with K+, Ca2+, NH4+, tetramethylammonium (TMA), trimethylphenylammonium (TMPA) and hexadecyltrimethylammonium (HDTMA) cations. The magnitude of sorption followed the order: TMPA-smectite≥HDTMA-smectite>NH4-smectite>K-smectite>Ca-smectite⩾TMA-smectite. The greatest sorption of carbamazepine by TMPA-smectite is attributed to the interaction of conjugate aromatic moiety in carbamazepine with the phenyl ring in TMPA through π-π interaction. Partitioning process is the primary mechanism for carbamazepine uptake by HDTMA-smectite. For NH4-smectite the urea moiety in carbamazepine interacts with exchanged cation NH4+ by H-bonding hence demonstrating relatively higher adsorption. Sorption by K-, Ca- and TMA-smectites from water occurs on aluminosilicate mineral surfaces. These results implicate that carbamazepine sorption by soils occurs primarily in soil organic matter, and soil mineral fractions play a secondary role. Desorption of carbamazepine from the sorbents manifested an apparent hysteresis. Increasing irreversibility of desorption vs. sorption was observed for K-, Ca-, TMA-, TMPA- and HDTMA-clays as aqueous carbamazepine concentrations increased. Desorption hysteresis of carbamazepine from K-, Ca-, NH4-smectites was greater than that from TMPA- and HDTMA-clays, suggesting that the sequestrated carbamazepine molecules in smectite interlayers are more resistant to desorption compared to those sorbed by organic phases in smectite clays. Copyright © 2010 Elsevier Ltd. All rights reserved.

  3. Water Vapor Desorption Characteristics of Honeycomb Type Sorption Element Composed of Organic Sorbent

    Science.gov (United States)

    Inaba, Hideo; Kida, Takahisa; Horibe, Akihiko; Kaneda, Makoto; Okamoto, Tamio; Seo, Jeong-Kyun

    This paper describes the water vapor desorption characteristics of honeycomb shape type sorbent element containing new organic sorbent of the bridged complex of sodium polyacrylate. The transient experiments in which the dry air was passed into the honeycomb type sorbent element sorbed water vapor were carried out under various conditions of air velocity, temperature, relative humidity and honeycomb length. The obtained data for desorption process were compared with those for sorption process. Finally, Sherwood number of mass transfer of the organic sorbent for desorption process was derived in terms of Reynolds number, modified Stefan number and non-dimensional honeycomb length.

  4. Temperature-programmed desorption of water and ammonia on ...

    Indian Academy of Sciences (India)

    Unknown

    Abstract. Temperature-programmed desorption (TPD) of water and ammonia over. ZrO2 and sulphated ZrO2 prepared by different methods has been investigated for measuring strong acidity and acidity distribution on sulphated zirconia-type solid super-acid catalysts. The TPD of water provides a simple reliable method for ...

  5. A study of the process of desorption of hexavalent chromium

    Directory of Open Access Journals (Sweden)

    W.B. Amorim

    2003-09-01

    Full Text Available In this work the process of desorption of hexavalent chromium, a toxic metal ion, from the marine algae Sargassum sp, following biosorption experiments 2³ factorial design was studied. A technique was applied to three eluents: HCl, H2SO4 and EDTA. Three factors of importance were evaluated: concentration of eluent, the ratio between mass of biosorbent and volume of eluent (S/L and process time. A statistical analysis of the experimental results showed that the three variables evaluated are significant for all three eluents. The models for chromium desorption were validated, as the results agreed well with the observed values. Through use of the response surface methodology, a factorial design based optimization technique; it was possible to identify the most suitable eluent and the interval of values for the process variables that resulted in the most significant desorption of chromium, which is relevant information for work aiming at process optimization.

  6. Temperature-programmed desorption of water and ammonia on ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Chemical Sciences; Volume 115; Issue 4. Temperature-programmed desorption of water and ammonia on sulphated zirconia catalysts for ... Author Affiliations. Vasant R Choudhary1 Abhijeet J Karkamkar1. Chemical Engineering Division, National Chemical Laboratory, Pune 411 008, India ...

  7. Adsorption and Desorption of Nitrogen and Water Vapor by clay

    Science.gov (United States)

    Cui, Deshan; Chen, Qiong; Xiang, Wei; Huang, Wei

    2015-04-01

    Adsorption and desorption of nitrogen and water vapor by clay has a significant impact on unsaturated soil physical and mechanical properties. In order to study the adsorption and desorption characteristics of nitrogen and water vapor by montmorillonite, kaolin and sliding zone soils, the Autosorb-iQ specific surface area and pore size analyzer instrument of United State was taken to carry out the analysis test. The adsorption and desorption of nitrogen at 77K and water vapor at 293K on clay sample were conducted. The theories of BET, FHH and hydration energy were taken to calculate the specific surface, surface fractal dimension and adsorption energy. The results show that the calculated specific surface of water vapor by clay is bigger than nitrogen adsorption test because clay can adsorb more water vapor molecule than nitrogen. Smaller and polar water vapor molecule can access the micropore and then adsorb on the mineral surface and mineral intralayer, which make the mineral surface cations hydrate and the mineral surface smoother. Bigger and nonpolar nitrogen molecule can not enter into the micropore as water vapor molecule and has weak interaction with clay surface.

  8. WATER ADSORPTION AND DESORPTION ISOTHERMS ON MILK POWDER: II. WHOLE MILK

    Directory of Open Access Journals (Sweden)

    Edgar M. Soteras

    2014-03-01

    Full Text Available The aim of this research was the determination of adsorption and desorption isotherms of cow whole milk powder. The experiments have been carried out at 15, 25 and 40 ºC, in ranges of moisture and water activity characteristic of normal conditions in which the processes of drying, packaging and storage are developed. By studying the influence of the temperature on the experimental plots, the isosteric adsorption heat was determined. Experimental data were correlated to the referential model of Guggenheim, Anderson and Boer (GAB. For both, adsorption and desorption, a good model fit was observed. The isotherms showed very similar shapes between them and, by comparing adsorption and desorption isotherms, the phenomenon of hysteresis was confirmed.

  9. Isosteric heat of water adsorption and desorption in homoionic alkaline-earth montmorillonites

    Science.gov (United States)

    Belhocine, M.; Haouzi, A.; Bassou, G.; Phou, T.; Maurin, D.; Bantignies, J. L.; Henn, F.

    2018-02-01

    The aim of the present work is to study by means of thermodynamic measurements and Infrared spectroscopy, the effect of the interlayer cations on the adsorption-desorption of water in the case of a montmorillonite exchanged with alkaline-earth metals. For the first time, the net isosteric heat of water adsorption and desorption is determined from isotherms recorded at three temperatures. The net isosteric heat is a very useful parameter for getting more insights into the sorption mechanism since it provides information about the sorption energy evolution which can be complementary to that obtained from structural or gravimetric measurements. The homoionic montmorillonite samples are prepared from purification and cationic exchanged in aqueous solution of the raw material, i.e. the reference SWy-2 Wyoming material. XRD at the dry state and elemental chemical analysis confirm that the treatment does not deteriorate the clay structure and yield the expected homoionic composition. The sorption isotherms measured at various temperatures show that the nature of the interlayer, i.e. exchangeable, cation changes the adsorbed/desorbed amount of water molecules for a given water relative pressure. The total amount of water adsorbed at P/P∘ = 0.5 follows the cation sequence Ca ∼ Mg>Ba while the sorption isosteric heats follow a slightly different sequence, i.e. Ca > Mg>Ba. This discrepancy between the adsorption and desorption heat is due to the higher irreversibility of water sorption process in the Ca exchanged montmorillonite. Finally, analysis of the IR spectra recorded at room temperature and under a primary vacuum reveals that the amount of adsorbed water follows the same sequence as that of the isosteric heat of adsorption and shows the coexistence of liquid-like and solid-like water confined in the interlayer space.

  10. Theoretical study of simultaneous water and VOCs adsorption and desorption in a silica gel rotor

    DEFF Research Database (Denmark)

    Zhang, G.; Zhang, Y.F.; Fang, Lei

    2008-01-01

    One-dimensional partial differential equations were used to model the simultaneous water and VOC (Volatile Organic Compound) adsorption and desorption in a silica gel rotor which was recommended for indoor air cleaning. The interaction among VOCs and moisture in the adsorption and desorption...... process was neglected in the model as the concentrations of VOC pollutants in typical indoor environment were much lower than that of moisture and the adsorbed VOCs occupied only a minor portion of adsorption capacity of the rotor. Consequently VOC transfer was coupled with heat and moisture transfer only...... by the temperatures of the rotor and the air stream. The VOC transfer equations were solved by discretizing them into explicit up-wind finite differential equations. The model was validated with experimental data. The calculated results suggested that the regeneration time designed for dehumidification may...

  11. Water adsorption-desorption isotherms of two-dimensional hexagonal mesoporous silica around freezing point.

    Science.gov (United States)

    Endo, Akira; Yamaura, Toshio; Yamashita, Kyohei; Matsuoka, Fumio; Hihara, Eiji; Daiguji, Hirofumi

    2012-02-01

    Zr-doped mesoporous silica with a diameter of approximately 3.8 nm was synthesized via an evaporation-induced self-assembly process, and the adsorption-desorption isotherms of water vapor were measured in the temperature range of 263-298 K. The measured adsorption-desorption isotherms below 273 K indicated that water confined in the mesopores did not freeze at any relative pressure. All isotherms had a steep curve, resulting from capillary condensation/evaporation, and a pronounced hysteresis. The hysteresis loop, which is associated with a delayed adsorption process, increased with a decrease in temperature. Furthermore, the curvature radius where capillary evaporation/condensation occurs was evaluated by the combined Kelvin and Gibbs-Tolman-Koening-Buff (GTKB) equations for the modification of the interfacial tension due to the interfacial curvature. The thickness of the water adsorption layer for capillary condensation was slightly larger, whereas that for capillary evaporation was slightly smaller than 0.7 nm. Copyright © 2011 Elsevier Inc. All rights reserved.

  12. Arsenic Adsorption and Desorption by Drinking Water Treatment Residuals: Incubation Studies

    Science.gov (United States)

    Vandanapu, V.; Sarkar, D.; Datta, R.; Makris, K.

    2005-05-01

    Arsenic (As) has been used for a long time in agricultural practices, primarily to control pests and noxious weeds. In many cases, the indiscriminate usage of toxic arsenical compounds has left a legacy of contaminated soils. Recent awareness of the toxicity of As at much lower concentrations than previously deemed to be dangerous has led to increased interest in the environmental chemistry of As. The immediate challenge, as perceived by various regulatory bodies is to develop a cost-effective, reliable and environmentally sound approach to cleaning up such contaminated soils. In-situ immobilization technologies are an attractive alternative to conventional remediation methods. One of the most interesting of these in-situ techniques is the use of Water Treatment Residuals (WTRs). The WTRs are by-products of drinking water purification processes and generally contain sediments, organic carbon, and Al/Fe oxides. The oxides are typically amorphous (with very high specific surface area) and have tremendous affinity for oxyanions (e.g., arsenate), due to their high positive surface charge. Recent studies conducted by our group have suggested that WTRs retain As and decrease arsenic mobility. However, a better understanding of As adsorption/desorption by WTRs is necessary for effective implementation of appropriate in-situ remedial strategies. Hence, the present study examines the potential use of WTRs (Al-WTR and Fe-WTR) as adsorbents for the removal of arsenate in solutions. Furthermore, it investigates the extent of desorption of the pre-adsorbed arsenate onto the WTR surfaces. Effects of various key parameters, such as solid solution ratio, equilibration time and arsenic concentration were examined to achieve the optimized conditions for arsenate adsorption. Preliminary batch adsorption experiments showed the optimum equilibration time to be 24 h and the solid/solution ratio to be 1:5 for arsenate adsorption. Sorption data has been evaluated using both Langmuir and

  13. Characterization of crude oil-water and solid -water interfaces and adsorption / desorption properties of crude oil fractions: The effect of low salinity water and pH

    Energy Technology Data Exchange (ETDEWEB)

    Farooq, Umer

    2010-09-15

    The reservoirs of conventional oil are rapidly depleting because of increased production and consumption of crude oil in the world. Mature and mostly depleted oil reservoirs require advanced recovery techniques to sustain the production rates. During the past years, a variety of enhanced oil recovery (EOR) methods have been developed and implemented to increase the oil recovery from mature reservoirs. Low Salinity Waterflooding (LSW) is an emerging EOR process of injecting water containing low concentrations (<4000 ppm) of total dissolved solids into the reservoir. This moderate cost process yields relatively higher incremental recoveries than other water based recovery methods. Investigation of mechanisms for increased recovery is quite challenging because this process depends upon complex crude oil/water/rock properties. This work was done to study the surface chemistry of typical reservoir surfaces where LSW can be used for EOR. The oil water and solid-water interfaces were characterised in low salinity aqueous solutions and investigated how the electrolytes and pH of solutions affect the interfacial and surface properties. The influence of low saline aqueous solution on the desorption behaviour of different fractions (acid-free oil and base-free oil) of crude oils was also explored. Reservoir minerals are sensitive to small changes in solution properties and therefore model, outcrop and reservoir particles were characterized in low salinity aqueous solutions. The extent of ionic adsorption on the mineral surfaces was found by various techniques. Particles were also characterized with respect to their elemental compositions. Asphaltene adsorption/desorption on reservoir rock surfaces play an important role in EOR processes. Various injection sequences of low saline aqueous solution of Na +, Ca2+ and sea water were considered to study the desorption of asphaltenes from silica surfaces. Composition of the aqueous phase influenced the interfacial properties of

  14. Molecular-Scale Description of SPAN80 Desorption from a Squalane-Water Interface.

    Science.gov (United States)

    Tan, L; Pratt, L R; Chaudhari, M I

    2017-12-15

    Extensive all-atom molecular dynamics calculations on the water-squalane interface for nine different loadings with sorbitan monooleate (SPAN80), at T = 300 K, are analyzed for the surface tension equation of state, desorption free-energy profiles as they depend on loading, and to evaluate escape times for adsorbed SPAN80 into the bulk phases. These results suggest that loading only weakly affects accommodation of a SPAN80 molecule by this squalane-water interface. Specifically, the surface tension equation of state is simple through the range of high tension to high loading studied, and the desorption free-energy profiles are weakly dependent on loading here. The perpendicular motion of the centroid of the SPAN80 headgroup ring is well-described by a diffusional model near the minimum of the desorption free-energy profile. Lateral diffusional motion is weakly dependent on loading. Escape times evaluated on the basis of a diffusional model and the desorption free energies are 7 × 10-2 s (into the squalane) and 3 × 102 h (into the water). The latter value is consistent with desorption times of related lab-scale experimental work.

  15. Strontium Adsorption and Desorption Reactions in Model Drinking Water Distribution Systems

    Science.gov (United States)

    2014-02-04

    One system was maintained with chlorine-disinfected drinking water and the other with the same water with secondary chloramine disinfection. Flow...constant flow conditions. Differences between adsorption and desorption based on disinfection type (chlorine versus chlorine plus chloramine ) cannot be...systems (DWDS). One system was maintained with chlorine-disinfected drinking water and the other with the same water with secondary chloramine

  16. Laboratory experiment on coalbed-methane desorption influenced by water injection and temperature

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, D.; Feng, Z.; Zhao, Y.

    2011-07-15

    The exploration of coalbed-methane (CBM) has significantly increased in the last decade, its exploitation is now widely spread. CBM exploitation technologies involve high-pressure water, which reduces the CBM-desorption capacity resulting in a low efficiency. This study has been conducted to examine the CBM desorption and output after water injection and temperature increase. They developed a new experimental system to simulate water-injection in ideal conditions and study the behaviour of water and methane in a coalbed. These experiments revealed that, at constant temperature, water injection pressure controls the CBM-desorption capacity; and that this capacity is highly increased when the temperature is increased. These results show that a higher temperature would increase the efficiency of CBM exploitation, thus producers are likely to use heating in future CBM technologies. Some advances were made in the knowledge of water pressure and temperature effects on desorption behaviour but further research has to be carried to fully define these effects.

  17. Description of the phosphorus sorption and desorption processes in lowland peaty clay soils

    NARCIS (Netherlands)

    Schoumans, O.F.

    2013-01-01

    To determine phosphorus (P) losses from agricultural land to surface water, information is needed about the behavior of P in soils. In this study, the sorption and desorption characteristics of lowland peaty clay soils are described based on experimental laboratory studies. The maximum P sorption

  18. Glyphosate sorption/desorption on biochars – Interactions of physical and chemical processes

    Science.gov (United States)

    BACKGROUND: Biochar, a carbon-rich product of biomass pyrolysis, could limit glyphosate transport in soil and remediate contaminated water. The present study investigates the sorption/desorption behavior of glyphosate on biochars prepared from different hardwoods at temperatures ranging from 350°C t...

  19. Optimization and kinetic modeling of cadmium desorption from citrus peels: A process for biosorbent regeneration

    Energy Technology Data Exchange (ETDEWEB)

    Njikam, Eloh, E-mail: ennjikam@alaska.edu [Department of Civil and Environmental Engineering, University of Alaska Fairbanks, P.O. Box 755900, Fairbanks, AK 99775 (United States); Schiewer, Silke, E-mail: sschiewer@alaska.edu [Department of Civil and Environmental Engineering, University of Alaska Fairbanks, P.O. Box 755900, Fairbanks, AK 99775 (United States)

    2012-04-30

    Graphical abstract: Cadmium was completely and quickly desorbed from grapefruit peels using 0.01 M HNO{sub 3}. The kinetics followed a novel 1st or 2nd order kinetic model, related to the remaining metal bound as the rate-determining reactant concentration. For 0.001 M HNO{sub 3}, desorption was incomplete and the model fit less perfect. Highlights: Black-Right-Pointing-Pointer Metal desorption was over 90% complete within 50 min for most desorbents. Black-Right-Pointing-Pointer Models for biosorbent desorption kinetics were developed. Black-Right-Pointing-Pointer Desorption kinetics best fit a novel first-order model related to remaining metal bound. Black-Right-Pointing-Pointer Cd uptake after desorption by HNO{sub 3} was similar to the original uptake. Black-Right-Pointing-Pointer The optimal desorbent was 0.1 or 0.01 M acid, being fast, efficient and cheap. - Abstract: Citrus peel biosorbents are efficient in removing heavy metals from wastewater. Heavy metal recovery and sorbent regeneration are important for the financial competitiveness of biosorption with other processes. The desorbing agents HNO{sub 3}, NaNO{sub 3}, Ca(NO{sub 3}){sub 2}, EDTA, S, S-EDDS, and Na-Citrate were studied at different concentrations to optimize cadmium elution from orange or grapefruit peels. In most cases, desorption was fast, being over 90% complete within 50 min. However sodium nitrate and 0.001 M nitric acid were less efficient. Several new models for desorption kinetics were developed. While zero-, first- and second-order kinetics are commonly applied for modeling adsorption kinetics, the present study adapts these models to describe desorption kinetics. The proposed models relate to the number of metal-filled binding sites as the rate-determining reactant concentration. A model based on first order kinetics with respect to the remaining metal bound performed best. Cd bound in subsequent adsorption after desorption was similar to the original amount bound for desorption by

  20. Combined effects of DOM extracted from site soil/compost and biosurfactant on the sorption and desorption of PAHs in a soil-water system

    Energy Technology Data Exchange (ETDEWEB)

    Yu Hui, E-mail: yuhui200@uregina.ca [Environmental Systems Engineering Program, Faculty of Engineering and Applied Science, University of Regina, Regina, SK S4S 0A2 (Canada); Huang Guohe, E-mail: gordon.huang@uregina.ca [Environmental Systems Engineering Program, Faculty of Engineering and Applied Science, University of Regina, Regina, SK S4S 0A2 (Canada); An Chunjiang, E-mail: an209@uregina.ca [Environmental Systems Engineering Program, Faculty of Engineering and Applied Science, University of Regina, Regina, SK S4S 0A2 (Canada); Wei Jia, E-mail: jia.wei@iseis.org [Environmental Systems Engineering Program, Faculty of Engineering and Applied Science, University of Regina, Regina, SK S4S 0A2 (Canada)

    2011-06-15

    Highlights: {yields} The combined DOM and biosurfactant significantly enhanced desorption of PAHs. {yields} Compost DOM exhibited higher desorption enhancement capacity than the soil DOM. {yields} Competition among PAHs, DOM and biosurfactant for sorption site determined desorption of PAHs from soil. {yields} Formation of DOM-biosurfactant complex enhance desorption extent of PAHs. - Abstract: The combined effects of DOM and biosurfactant on the sorption/desorption behavior of phenanthrene (PHE) and pyrene (PYR) in soil water systems were systematically investigated. Two origins of DOMs (extracted from soil and extracted from food waste compost) and an anionic biosurfactant (rhamnolipid) were introduced. The presence of DOM in the aqueous phase could decrease the sorption of PAHs, thus influence their mobility. Desorption enhancement for both PHE and PYR in the system with compost DOM was greater than that in the soil DOM system. This is due to the differences in specific molecular structures and functional groups of two DOMs. With the co-existence of biosurfactant and DOM, partitioning is the predominant process and the desorption extent was much higher than the system with DOM or biosurfactant individually. For PHE, the desorption enhancement of combined DOM and biosurfactant was larger than the sum of DOM or biosurfactant; however desorption enhancement for PYR in the combined system was less than the additive enhancement in two individual system under low PAH concentration. This could be explained as the competition sorption among PAHs, DOM and biosurfactant. The results of this study will help to clarify the transport of petroleum pollutants in the remediation of HOCs-contaminated soils.

  1. Molecular-scale Description of SPAN80 Desorption from the Squalane-Water Interface

    OpenAIRE

    Tan, L.; Pratt, L. R.; Chaudhari, M. I.

    2016-01-01

    Extensive all-atom molecular dynamics calculations on the water-squalane interface for nine different loadings with sorbitan monooleate (SPAN80), at $T=300$K, are analyzed for the surface tension equation of state, desorption free energy profiles as they depend on loading, and to evaluate escape times for absorbed SPAN80 into the bulk phases. These results suggest that loading only weakly affects accommodation of a SPAN80 molecule by this squalane-water interface. Specifically, the surface te...

  2. Desorption Kinetics of Ar, Kr, Xe, N2, O2, CO, Methane, Ethane, and Propane from Graphene and Amorphous Solid Water Surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Smith, R. Scott; May, Robert A.; Kay, Bruce D.

    2016-03-03

    The desorption kinetics for Ar, Kr, Xe, N2, O2, CO, methane, ethane, and propane from grapheme covered Pt(111) and amorphous solid water (ASW) surfaces are investigated using temperature programmed desorption (TPD). The TPD spectra for all of the adsorbates from graphene have well-resolved first, second, third, and multi- layer desorption peaks. The alignment of the leading edges is consistent the zero-order desorption for all of the adsorbates. An Arrhenius analysis is used to obtain desorption energies and prefactors for desorption from graphene for all of the adsorbates. In contrast, the leading desorption edges for the adsorbates from ASW do not align (for coverages < 2 ML). The non-alignment of TPD leading edges suggests that there are multiple desorption binding sites on the ASW surface. Inversion analysis is used to obtain the coverage dependent desorption energies and prefactors for desorption from ASW for all of the adsorbates.

  3. Dynamic Adsorption/Desorption Process Model of Capacitive Deionization

    NARCIS (Netherlands)

    Biesheuvel, P.M.; Limpt, van B.; Wal, van der A.

    2009-01-01

    In capacitive deionization (CDI), an electrical potential difference is applied across oppositely placed electrodes, resulting in the adsorption of ions from aqueous solution and a partially ion-depleted product stream. CDI is a dynamic process which operates in a sequential mode; i.e., after a

  4. Critical review: Radionuclide transport, sediment transport, and water quality mathematical modeling; and radionuclide adsorption/desorption mechanisms

    Energy Technology Data Exchange (ETDEWEB)

    Onishi, Y.; Serne, R.J.; Arnold, E.M.; Cowan, C.E.; Thompson, F.L. [Pacific Northwest Lab., Richland, WA (United States)

    1981-01-01

    This report describes the results of a detailed literature review of radionuclide transport models applicable to rivers, estuaries, coastal waters, the Great Lakes, and impoundments. Some representatives sediment transport and water quality models were also reviewed to evaluate if they can be readily adapted to radionuclide transport modeling. The review showed that most available transport models were developed for dissolved radionuclide in rivers. These models include the mechanisms of advection, dispersion, and radionuclide decay. Since the models do not include sediment and radionuclide interactions, they are best suited for simulating short-term radionuclide migration where: (1) radionuclides have small distribution coefficients; (2) sediment concentrations in receiving water bodies are very low. Only 5 of the reviewed models include full sediment and radionuclide interactions: CHMSED developed by Fields; FETRA SERATRA, and TODAM developed by Onishi et al, and a model developed by Shull and Gloyna. The 5 models are applicable to cases where: (1) the distribution coefficient is large; (2) sediment concentrations are high; or (3) long-term migration and accumulation are under consideration. The report also discusses radionuclide absorption/desorption distribution ratios and addresses adsorption/desorption mechanisms and their controlling processes for 25 elements under surface water conditions. These elements are: Am, Sb, C, Ce, Cm, Co, Cr, Cs, Eu, I, Fe, Mn, Np, P, Pu, Pm, Ra, Ru, Sr, Tc, Th, {sup 3}H, U, Zn and Zr.

  5. Processes of adsorption/desorption of iodides and cadmium cations onto/from Ag(111

    Directory of Open Access Journals (Sweden)

    VLADIMIR D. JOVIĆ

    2011-02-01

    Full Text Available In this work, the adsorption/desorption processes of iodides and cadmium cations in the presence of iodides onto/from Ag(111 were investigated. It was shown that both processes were complex, characterized by several peaks on the cyclic voltammograms (CVs. By PeakFit analysis of the recorded CVs and subsequent fitting of the obtained peaks by the Frumkin adsorption isotherm, the interaction parameter (f and the Gibbs energy of adsorption (DGads for each adsorbed phase were determined. In the case of iodide adsorption, four peaks were characterized by negative values of f, indicating attractive lateral interaction between the adsorbed anions, while two of them possessed value of f < –4, indicating phase transition processes. The adsorption/desorption processes of cadmium cations (underpotential deposition – UPD of cadmium in the presence of iodide anions was characterized by two main peaks, each of them being composed of two or three peaks with negative values of f. By the analysis of charge vs. potential dependences obtained either from the CVs or current transients on potentiostatic pulses, it was concluded that adsorbed iodides did not undergo desorption during the process of Cd UPD, but became replaced by Cd ad-atoms and remained adsorbed on top of a Cd layer and/or in between Cd the ad-atoms.

  6. [Combination process of microwave desorption-catalytic combustion for toluene treatment].

    Science.gov (United States)

    Cao, Xiao-Qiang; Zhang, Hao; Huang, Xue-Min

    2013-07-01

    Using activated carbon as adsorbent, toluene waste gas was treated by adsorption process. After the adsorption process was completed, the adsorbent was desorbed by microwave irradiation; then Cu-Mn oxide composite catalysts were prepared by impregnation and the desorbed toluene gas was treated by catalytic combustion so as to completely purify the pollutant. The concentration of toluene was measured by gas chromatography (GC). The results indicated that it is feasible to add air to provide oxygen to the desorbed gas after the completion of the desorption process, in order to achieve the catalytic combustion; the ratio of desorbed gas and air was 1 : 1 (volume ratio), and the corresponding catalytic space velocity was 2.67 s(-1). Desorption temperature could affect the concentration of toluene in the desorption gas thereby affecting the catalytic combustion efficiency; the results indicated that 400 degrees C was an appropriate temperature for desorbing the activated carbon. When the catalytic combustion was kept at 300 degrees C, the final toluene treatment efficiency was higher than 90%, which was higher than 95% during the most time of the treatment process.

  7. Natural and surfactant modified zeolites: A review of their applications for water remediation with a focus on surfactant desorption and toxicity towards microorganisms.

    Science.gov (United States)

    Reeve, Peter J; Fallowfield, Howard J

    2018-01-01

    The objective of this review is to highlight the need for further investigation of microbial toxicity caused by desorption of surfactant from Surfactant Modified Zeolite (SMZ). SMZ is a low cost, versatile permeable reactive media which has the potential to treat multiple classes of contaminants. With this combination of characteristics, SMZ has significant potential to enhance water and wastewater treatment processes. Surfactant desorption has been identified as a potential issue for the ongoing usability of SMZ. Few studies have investigated the toxicity of surfactants used in zeolite modification towards microorganisms and fewer have drawn linkages between surfactant desorption and surfactant toxicity. This review provides an overview of natural zeolite chemistry, characteristics and practical applications. The chemistry of commonly used surfactants is outlined, along with the kinetics that drive their adsorption to the zeolite surface. Methodologies to characterise this surfactant loading are also described. Applications of SMZ in water remediation are highlighted, giving focus to applications which deal with biological pollutants and where microorganisms play a role in the remediation process. Studies that have identified surfactant desorption from SMZ are outlined. Finally, the toxicity of a commonly used cationic surfactant towards microorganisms is discussed. This review highlights the potential for surfactant to desorb from the zeolite surface and the need for further research into the toxicity of this desorbed surfactant towards microorganisms, including pathogens and environmental microbes. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Analysis of organic compounds in water by direct adsorption and thermal desorption. [Dissertation

    Energy Technology Data Exchange (ETDEWEB)

    Ryan, J.P. Jr.

    1980-03-01

    An instrument was designed and constructed that makes it possible to thermally desorb organic compounds from wet adsorption traps to a gas chromatograph in an efficient and reproducible manner. Based on this device, a method of analyzing organics in water was developed that is rapid, sensitive, and of broader scope than previously published methods. The system was applied to the analysis of compounds with a wide range of volatilities. Temperature and flow parameters were investigated and specific procedures for quantitation were established. Real samples, including tap water and well water, were also analyzed with this system. Depending on the analysis requirements, the thermal desorption instrument can be used with either packed column or high resolution open-tubular column gas chromatography. The construction plans of normal and high-resolution systems are presented along with chromatograms and data produced by each. Finally, an improved thermal desorption instrument is described. Modifications to the basic system, including splitless injection onto a capillary column, automation, dual cryogenic trapping, reduction of scale, and effluent splitting to dual detection are discussed at length as they relate to the improved instrument.

  9. Adsorption-desorption processes of polydisperse mixtures on a triangular lattice

    Science.gov (United States)

    Dujak, D.; Lončarević, I.; Budinski-Petković, Lj.; Vrhovac, S. B.; Karač, A.

    2015-03-01

    Adsorption-desorption processes of polydisperse mixtures on a triangular lattice are studied by numerical simulations. Mixtures are composed of the shapes of different numbers of segments and rotational symmetries. Numerical simulations are performed to determine the influence of the number of mixture components and the length of the shapes making the mixture on the kinetics of the deposition process. We find that, above the jamming limit, the time evolution of the total coverage of a mixture can be described by the Mittag-Leffler function θ (t ) =θ∞-Δ θ Eβ[-(t/τ ) β] for all the mixtures we have examined. Our results show that the equilibrium coverage decreases with the number of components making the mixture and also with the desorption probability, via corresponding stretched exponential laws. For the mixtures of equal-sized objects, we propose a simple formula for predicting the value of the steady-state coverage fraction of a mixture from the values of the steady-state coverage fractions of pure component shapes.

  10. Adsorption-desorption processes of polydisperse mixtures on a triangular lattice.

    Science.gov (United States)

    Dujak, D; Lončarević, I; Budinski-Petković, Lj; Vrhovac, S B; Karač, A

    2015-03-01

    Adsorption-desorption processes of polydisperse mixtures on a triangular lattice are studied by numerical simulations. Mixtures are composed of the shapes of different numbers of segments and rotational symmetries. Numerical simulations are performed to determine the influence of the number of mixture components and the length of the shapes making the mixture on the kinetics of the deposition process. We find that, above the jamming limit, the time evolution of the total coverage of a mixture can be described by the Mittag-Leffler function θ(t)=θ∞-ΔθE[-(t/τ)β] for all the mixtures we have examined. Our results show that the equilibrium coverage decreases with the number of components making the mixture and also with the desorption probability, via corresponding stretched exponential laws. For the mixtures of equal-sized objects, we propose a simple formula for predicting the value of the steady-state coverage fraction of a mixture from the values of the steady-state coverage fractions of pure component shapes.

  11. Processes for desorption from LiAlO sub 2 treated with H sub 2 as studied by temperature programmed desorption

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, A.K.

    1990-01-01

    The energetics and kinetics of the evolution of H{sub 2}O and H{sub 2} from LiAlO{sub 2} are being studied by the temperature programmed desorption technique. The concentrations of H{sub 2}, H{sub 2}O, N{sub 2}, and O{sub 2} in a helium stream during a temperature ramp are measured simultaneously with a mass spectrometer. Blank experiments with an empty sample tube showed that square wave spikes of H{sub 2} introduced into the helium gas stream were severely distorted by reaction with the tube walls. The tube could be stabilized, however, by sufficiently prolonged heat treatment with H{sub 2} so that H{sub 2} peaks would not be distorted up to approximately 923 K(650{degree}C). The amount of H{sub 2}adsorption/desorption is small compared to the amount of H{sub 2}O adsorption/desorption. After prolonged treatment with helium containing 990 ppm H{sub 2} at 400{degree}C, H{sub 2}O evolution into the He-H{sub 2} stream was observed during 473 to 1023 K (200 to 750{degree}C) ramps at rates of 2 or 5.6 K/min. The different peak shapes reflecting this process were deconvoluted to show that they are composites of only 2 or 3 reproducible processes. The activation energies and pre-exponential terms was evaluated. The different behavior originates in the differences among different surface sites for adsorption. The interpretation of higher temperature peaks (above 873 K (650{degree}C)) must still consider the possibility of contributions from interactions with steel walls. It was found that H{sub 2} enhances evolution of N{sub 2} from the steel. 1 tab., 6 figs., 11 refs.

  12. SUPERFUND TREATABILITY CLEARINGHOUSE: TECHNOLOGY DEMONSTRATION OF A THERMAL DESORPTION/UV PHOTOLYSIS PROCESS FOR DECONTAMINATING SOILS CONTAINING HERBICIDE ORANGE

    Science.gov (United States)

    This treatability study report presents the results of laboratory and field tests on the effectiveness of a new decontamination process for soils containing 2,4-D/2,4,5-T and traces of dioxin. The process employs three operations, thermal desorption, condensation and absorp...

  13. Sorption and desorption of tritiated water vapor on piping materials of nuclear fusion reactor

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, Satoru; Ohmori, Rumi [Tokyo Univ. (Japan). Faculty of Engineering

    1996-10-01

    Sorption and desorption of D{sub 2}O on Cr{sub 2}O{sub 3}, NiO, SS316 powders were studied at ambient temperature. When D{sub 2}O were contacted with samples after drying at 303K, broad peak was observed at 2100-2700cm{sup -1} on Cr{sub 2}O{sub 3} and NiO. Sorption and desorption rate depended on wave numbers. Isotope exchange rate with H{sub 2}O vapor was faster than dry desorption rate. By heating pretreatment, sorption amount and desorption rate for Cr{sub 2}O{sub 3} and NiO decreased. For SS316, broad peak was observed only after heating pretreatment at 673K. (author)

  14. Experimental study of water desorption isotherms and thin-layer convective drying kinetics of bay laurel leaves

    Science.gov (United States)

    Ghnimi, Thouraya; Hassini, Lamine; Bagane, Mohamed

    2016-12-01

    The aim of this work is to determine the desorption isotherms and the drying kinetics of bay laurel leaves ( Laurus Nobilis L.). The desorption isotherms were performed at three temperature levels: 50, 60 and 70 °C and at water activity ranging from 0.057 to 0.88 using the statistic gravimetric method. Five sorption models were used to fit desorption experimental isotherm data. It was found that Kuhn model offers the best fitting of experimental moisture isotherms in the mentioned investigated ranges of temperature and water activity. The Net isosteric heat of water desorption was evaluated using The Clausius-Clapeyron equation and was then best correlated to equilibrium moisture content by the empirical Tsami's equation. Thin layer convective drying curves of bay laurel leaves were obtained for temperatures of 45, 50, 60 and 70 °C, relative humidity of 5, 15, 30 and 45 % and air velocities of 1, 1.5 and 2 m/s. A non linear regression procedure of Levenberg-Marquardt was used to fit drying curves with five semi empirical mathematical models available in the literature, The R2 and χ2 were used to evaluate the goodness of fit of models to data. Based on the experimental drying curves the drying characteristic curve (DCC) has been established and fitted with a third degree polynomial function. It was found that the Midilli Kucuk model was the best semi-empirical model describing thin layer drying kinetics of bay laurel leaves. The bay laurel leaves effective moisture diffusivity and activation energy were also identified.

  15. Experimental study and modelling of water sorption/desorption isotherms on two agricultural products: Apple and carrot

    Science.gov (United States)

    Timoumi, S.; Zagrouba, F.; Mihoubi, D.; Tlili, M. M.

    2004-12-01

    This work is focused on some properties of dried apple (Red Chief) and carrot (Misky). Water sorption isotherms of carrot and apple were investigated at three temperatures: 30, 40 and 60°C, corresponding to drying temperatures, by the static method consisting of the use of different sulphuric acid solutions. Guggenheim-Anderson-de Boer (G.A.B) model is found to describe the experimental curves better than Henderson, Hasley and Oswin models with a correlation coefficient superior to 0.97 for both products. The hysteresis phenomenon was clearly observed in the case of apple isotherms. The experimental data were also used to determine the isosteric enthalpy of desorption of apple and carrot. The isosteric enthalpy of desorption decreased with increase in moisture content and the trend became asymptotic.

  16. Desorption of Water from Distinct Step Types on a Curved Silver Crystal

    Directory of Open Access Journals (Sweden)

    Jakrapan Janlamool

    2014-07-01

    Full Text Available We have investigated the adsorption of H2O onto the A and B type steps on an Ag single crystal by temperature programmed desorption. For this study, we have used a curved crystal exposing a continuous range of surface structures ranging from [5(111 × (100] via (111 to [5(111 × (110]. LEED and STM studies verify that the curvature of our sample results predominantly from monoatomic steps. The sample thus provides a continuous array of step densities for both step types. Desorption probed by spatially-resolved TPD of multilayers of H2O shows no dependence on the exact substrate structure and thus confirms the absence of thermal gradients during temperature ramps. In the submonolayer regime, we observe a small and linear dependence of the desorption temperature on the A and B step density. We argue that such small differences are only observable by means of a single curved crystal, which thus establishes new experimental benchmarks for theoretical calculation of chemically accurate binding energies. We propose an origin of the observed behavior based on a “two state” desorption model.

  17. Desorption of water from distinct step types on a curved silver crystal.

    Science.gov (United States)

    Janlamool, Jakrapan; Bashlakov, Dima; Berg, Otto; Praserthdam, Piyasan; Jongsomjit, Bunjerd; Juurlink, Ludo B F

    2014-07-25

    We have investigated the adsorption of H2O onto the A and B type steps on an Ag single crystal by temperature programmed desorption. For this study, we have used a curved crystal exposing a continuous range of surface structures ranging from [5(111) × (100)] via (111) to [5(111) × (110)]. LEED and STM studies verify that the curvature of our sample results predominantly from monoatomic steps. The sample thus provides a continuous array of step densities for both step types. Desorption probed by spatially-resolved TPD of multilayers of H2O shows no dependence on the exact substrate structure and thus confirms the absence of thermal gradients during temperature ramps. In the submonolayer regime, we observe a small and linear dependence of the desorption temperature on the A and B step density. We argue that such small differences are only observable by means of a single curved crystal, which thus establishes new experimental benchmarks for theoretical calculation of chemically accurate binding energies. We propose an origin of the observed behavior based on a "two state" desorption model.

  18. [EXAFS studies on adsorption-desorption mechanism of Zn at the manganite-water interface].

    Science.gov (United States)

    Pan, Gang; Qin, Yanwen; Li, Xianliang; Hu, Tiandou; Xie, Yaning; Wu, Ziyu

    2003-05-01

    Microscopic structures of Zn(II) surface complexes adsorbed at the manganite(gamma-MnOOH)-water interface were studied using extended X-ray absorption fine structure(EXAFS) spectroscopy. Quantitative analysis of the EXAFS spectra showed that, in a 0.1 mol/L NaNO3 solution of pH 7.5, Zn(II) was adsorbed onto the solid surface by sharing the oxygen atom in the hydrous Zn2+ ions and in the structural unit MnO6 on the manganite surface. Most of the adsorbed Zn(II) was in the form of octahedral Zn(H2O2)(6)2+, but part of Zn(II) was adsorbed as tetrahedral Zn(OH)2 or Zn(OH)(4)2-. The average Zn-O bond length was 1.998 +/- 0.010 A (n = 3). The ZnO polyhedron of the hydrous Zn2+ ions was linked to the octahedron MnO6 of the manganite in two modes by sharing two O atoms on the edges of the polyhedral and/or one O atom on the corners of the polyhedral. EXAFS analysis of the second sphere indicated that Zn (II) adsorbed on the manganite resulted in two Zn-Mn atomic distances of 3.08 +/- 0.024A (n = 3) (R1) and 3.54 +/- 0.018 A (n = 3) (R2), corresponding to the edge-linkage (stronger adsorption site) and corner-linkage (weaker adsorption site), respectively. This result confirmed the basic hypothesis of Metastable Equilibrium Adsorption (MEA) theory from a molecular level that adsorption density gamma (mol/m2) is not a state variable, because adsorption density for the same adsorbate may have different chemical potential values due to different microscopic structure and adsorbate energy status. Macroscopic adsorption-desorption experiments showed that adsorption of Zn(II) onto manganite was largely irreversible (big adsorption hysteresis). EXAFS results indicated that the microscopic mechanism for the adsorption irreversibility was corresponded to the strong adsorption sites of edge sharing linkage between the adsorbate and adsorbent polyhedra.

  19. Studies of hydrogen absorption and desorption processes in advanced intermetallic hydrides

    Energy Technology Data Exchange (ETDEWEB)

    Sato, Masashi

    2005-07-01

    This work is a part of the research program performed in the Department of Energy Systems, Institute for Energy Technology (Kjeller, Norway), which is focused on the development of the advanced hydrogen storage materials. The activities are aimed on studies of the mechanisms of hydrogen interactions with intermetallic alloys with focus on establishing an interrelation between the crystal structure, thermodynamics and kinetics of the processes in the metal-hydrogen systems, on the one hand, and hydrogen storage properties (capacity, rates of desorption, hysteresis). Many of the materials under investigation have potential to be applied in applications, whereas some already have been commercialised in the world market. A number of metals take up considerable amounts of hydrogen and form chemical compounds with H, metal hydrides. Unfortunately, binary hydrides are either very stable (e.g. for the rare earth metals [RE], Zr, Ti, Mg: metal R) or are formed at very high applied pressures of hydrogen gas (e.g. for the transition metals, Ni, Co, Fe, etc.: Metal T). However, hydrogenation process becomes easily reversible at very convenient from practical point of view conditions, around room temperature and at H2 pressures below 1 MPa for the two-component intermetallic alloys R{sub x}T{sub y}. This raised and maintains further interest to the intermetallic hydrides as solid H storage materials. Materials science research of this thesis is focused on studies of the reasons staying behind the beneficial effect of two non-transition elements M(i.e., In and Sn) contributing to the formation of the ternary intermetallic alloys R{sub x}T{sub y}M{sub 2}., on the hydrogen storage behaviours. Particular focus is on two aspects where the remarkable improvement of ordinary metal hydrides is achieved via introduction of In and Sn: a) Increase of the volume density of stored hydrogen in solid materials to the record high level. b) Improvement of the kinetics of hydrogen charge and

  20. Production of O2 through dismutation of H2O2 during water ice desorption: a key to understanding comet O2 abundances

    Science.gov (United States)

    Dulieu, F.; Minissale, M.; Bockelée-Morvan, D.

    2017-01-01

    Context. Detection of molecular oxygen and prediction of its abundance have long been a challenge for astronomers. The low abundances observed in few interstellar sources are well above the predictions of current astrochemical models. During the Rosetta mission, an unexpectedly high abundance of O2 was discovered in the comet 67P/Churyumov-Gerasimenko's coma. A strong correlation between O2 and H2O productions is observed, whereas no such correlation is observed between O2 and either of CO or N2. Aims: We suggest that the O2 molecule may be formed during the evaporation of water ice. We propose a possible reaction: the dismutation of H2O2 (2 H2O2-→ 2 H2O + O2), a molecule which should be co-produced during the water ice mantle growth on dust grains. We aim to test this hypothesis under realistic experimental conditions. Methods: We performed two sets of experiments. They consist of producing a mixture of D2O and D2O2 via the reaction of O2 and D on a surface held at 10 K. The first set is made on a silicate substrate, and explores the limit of thin films, in order to prevent any complication due to trapping during the desorption. The second set is performed on a pre-deposited H2O ice substrate and mimics the desorption of mixed ice. Results: In thin films, O2 is produced by the dismutation of H2O2, even at temperatures as low as 155 K. Mixed with water, H2O2 desorbs after the water ice sublimation and even more desorption of O2 is observed. Conclusions: H2O2, synthesised during the growth of interstellar ices (or by later processing), desorbs at the latest stage of the water sublimation and undergoes the dismutation reaction. Therefore an O2 release in the gas phase should occur at the end of the evaporation of ice mantles. Temperature gradients along the geometry of clouds, or interior of comets, should blend the different stages of the sublimation. Averaged along the whole process, a mean value of the O2/H2O ratio of a few percent in the gas phase seems

  1. Effect of desorption and recombination on texture development in hydrogenation–disproportionation–desorption–recombination processed Nd–Fe–B magnets

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Tae-Hoon; An, Byeong-Seon [School of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon 16419 (Korea, Republic of); Cha, Hee-Ryoung [Powder & Ceramics Division, Korea Institute of Materials Science, Changwon 51508 (Korea, Republic of); School of Materials Science and Engineering, Pusan National University, Busan 46241 (Korea, Republic of); Lee, Jung-Goo, E-mail: jglee36@kims.re.kr [Powder & Ceramics Division, Korea Institute of Materials Science, Changwon 51508 (Korea, Republic of); Kwon, Hae-Woong, E-mail: hwkwon@pknu.ac.kr [Department of Materials Science and Engineering, Pukyong National University, Busan 48513 (Korea, Republic of); Yang, Cheol-Woong, E-mail: cwyang@skku.edu [School of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon 16419 (Korea, Republic of)

    2016-07-05

    The microstructural evolution of Nd–Fe–B magnets during a hydrogenation–disproportionation–desorption–recombination (HDDR) process was investigated, with particular focus on the effects of the desorption–recombination (DR) stage of the process. Samples that went through the DR process under different conditions were compared to examine the texture development during the reaction. Even though the same hydrogenation–disproportionation (HD) treatment was carried out on all samples before the DR reaction, variations in conditions of the latter significantly affected the development of texture in the samples. In consideration of the microstructural evolution, magnetic properties, and thermodynamics, nucleation of recombined Nd{sub 2}Fe{sub 14}B grains was found to occur not only at the NdH{sub 2}/Fe{sub 2}B interfaces but also at the NdH{sub 2}/α-Fe interfaces, and it was affected by the desorption of hydrogen. Preferential growth of nuclei at the NdH{sub 2}/Fe{sub 2}B interfaces, which led to a highly textured Nd{sub 2}Fe{sub 14}B phase, could be induced by slow desorption and recombination with a low driving force. Hydrogen desorption at a slower rate was important for achieving high magnetic anisotropy in the HDDR-processed Nd–Fe–B powders. - Highlights: • The DR condition significantly affected magnetic anisotropy of HDDR powder. • Mechanism of texture development during the DR stage was suggested. • Recombined Nd{sub 2}Fe{sub 14}B could be nucleated at both NdH{sub 2}/Fe{sub 2}B and NdH{sub 2}/α-Fe interfaces. • Hydrogen pressure during DR reaction affects the preference of nucleation site. • Slow DR process is important for high magnetic anisotropy.

  2. 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.

  3. Oxygen isotopic fractionation of O₂ during adsorption and desorption processes using molecular sieve at low temperatures.

    Science.gov (United States)

    Ahn, Insu; Kusakabe, Minoru; Lee, Jong Ik

    2014-06-15

    Cryogenic trapping using molecular sieves is commonly used to collect O2 extracted from silicates for (17)O/(16)O and (18)O/(16)O analyses. However, gases which interfere with (17)O/(16)O analysis, notably NF3, are also trapped and their removal is essential for accurate direct measurement of the (17)O/(16)O ratio. It is also necessary to identify and quantify any isotopic fractionation associated with the use of cryogenic trapping using molecular sieves. The oxygen isotopic compositions of O2 before and after desorption from, and adsorption onto, 13X and 5A molecular sieves (MS13X and MS5A) at 0°C, -78°C, -114°C, and -130°C were measured in order to determine the oxygen isotopic fractionation at these temperatures. We also investigated whether isotopic fractionation occurred when O2 gas was transferred sequentially into a second cold finger, also containing molecular sieve. It was confirmed that significant oxygen isotopic fractionation occurs between the gaseous O2 and that adsorbed onto molecular sieve, if desorption and adsorption are incomplete. As the fraction of released or untrapped O2 becomes smaller with decreasing trapping temperature (from 0 to -130°C), the isotopic fractionation becomes larger. Approximately half of the total adsorbed O2 is released from the molecular sieve during desorption at -114°C, which is the temperature recommended for separation from NF3 (retained on the molecular sieve), and this will interfere with (17)O/(16)O measurements. The use of a single cold finger should be avoided, because partial desorption is accompanied by oxygen isotopic fractionation, thereby resulting in inaccurate isotopic data. The use of a dual cold finger arrangement is recommended because, as we have confirmed, the transfer of O2 from the first trap to the second is almost 100%. However, even under these conditions, a small isotopic fractionation (0.18 ± 0.05‰ in δ(17)O values and 0.26 ± 0.06‰ in δ(18)O values) occurred, with O2 in

  4. Comparison of a disposable sorptive sampler with thermal desorption in a gas chromatographic inlet, or in a dedicated thermal desorber, to conventional stir bar sorptive extraction-thermal desorption for the determination of micropollutants in water.

    Science.gov (United States)

    Wooding, Madelien; Rohwer, Egmont R; Naudé, Yvette

    2017-09-01

    The presence of micropollutants in the aquatic environment is a worldwide environmental concern. The diversity of micropollutants and the low concentration levels at which they may occur in the aquatic environment have greatly complicated the analysis and detection of these chemicals. Two sorptive extraction samplers and two thermal desorption methods for the detection of micropollutants in water were compared. A low-cost, disposable, in-house made sorptive extraction sampler was compared to SBSE using a commercial Twister sorptive sampler. Both samplers consisted of polydimethylsiloxane (PDMS) as a sorptive medium to concentrate micropollutants. Direct thermal desorption of the disposable samplers in the inlet of a GC was compared to conventional thermal desorption using a commercial thermal desorber system (TDS). Comprehensive gas chromatography coupled to time-of-flight mass spectrometry (GC × GC-TOFMS) was used for compound separation and identification. Ten micropollutants, representing a range of heterogeneous compounds, were selected to evaluate the performance of the methods. The in-house constructed sampler, with its associated benefits of low-cost and disposability, gave results comparable to commercial SBSE. Direct thermal desorption of the disposable sampler in the inlet of a GC eliminated the need for expensive consumable cryogenics and total analysis time was greatly reduced as a lengthy desorption temperature programme was not required. Limits of detection for the methods ranged from 0.0010 ng L-1 to 0.19 ng L-1. For most compounds, the mean (n = 3) recoveries ranged from 85% to 129% and the % relative standard deviation (% RSD) ranged from 1% to 58% with the majority of the analytes having a %RSD of less than 30%. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Enrichment of tropical peat with micronutrients for agricultural applications: evaluation of adsorption and desorption processes

    Energy Technology Data Exchange (ETDEWEB)

    Melo, Camila de A.; Oliveira, Lilian K. de; Fraceto, Leonardo F.; Rosa, Andre H., E-mail: ahrosa@sorocaba.unesp.br [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Sorocaba, SP (Brazil). Dept. de Engenharia Ambiental; Goveia, Danielle [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Araraquara, SP (Brazil). Inst. de Quimica

    2014-01-15

    The objective of this work was to evaluate the adsorption and desorption of micronutrients in tropical peats, from the perspective of potential agricultural applications. Adsorption experiments were performed at different pH values, using solutions containing individual and multiple metal ions. Maximum adsorption capacity occurred at pH 6.0, and the order of affinity was Cu > Fe > Co > Ni > Zn = Mn. Release of the micronutrients was evaluated at different pH values, using an aqueous medium as well as soil and plants. Release of the micronutrients was most efficient at pH 6.0, and followed the order: Fe > Zn > Mn > Co = Ni > Cu. Micronutrient release to the soil was accompanied by uptake by the plant. The use of tropical peat enriched with micronutrients could contribute to improved agricultural productivity, since the release profile of the micronutrients can effectively stimulate plant growth. (author)

  6. On plate graphite supported sample processing for simultaneous lipid and protein identification by matrix assisted laser desorption ionization mass spectrometry.

    Science.gov (United States)

    Calvano, Cosima Damiana; van der Werf, Inez Dorothé; Sabbatini, Luigia; Palmisano, Francesco

    2015-05-01

    The simultaneous identification of lipids and proteins by matrix assisted laser desorption ionization-mass spectrometry (MALDI-MS) after direct on-plate processing of micro-samples supported on colloidal graphite is demonstrated. Taking advantages of large surface area and thermal conductivity, graphite provided an ideal substrate for on-plate proteolysis and lipid extraction. Indeed proteins could be efficiently digested on-plate within 15 min, providing sequence coverages comparable to those obtained by conventional in-solution overnight digestion. Interestingly, detection of hydrophilic phosphorylated peptides could be easily achieved without any further enrichment step. Furthermore, lipids could be simultaneously extracted/identified without any additional treatment/processing step as demonstrated for model complex samples such as milk and egg. The present approach is simple, efficient, of large applicability and offers great promise for protein and lipid identification in very small samples. Copyright © 2015 Elsevier B.V. All rights reserved.

  7. Mechanistic study of lead desorption during the leaching process of ion-absorbed rare earths: pH effect and the column experiment.

    Science.gov (United States)

    Tang, Jie; Xue, Qiang; Chen, Honghan; Li, Wenting

    2017-05-01

    High concentrations of ammonium sulfate, often used in the in situ mining process, can result in a decrease of pH in the environment and dissolution of rare earth metals. Ammonium sulfate can also cause desorption of toxic heavy metals, leading to environmental and human health implications. In this study, the desorption behavior and fraction changes of lead in the ion-absorbed rare earth ore were studied using batch desorption experiments and column leaching tests. Results from batch desorption experiments showed that the desorption process of lead included fast and slow stages and followed an Elovich model well. The desorption rate and the proportion of lead content in the solution to the total lead in the soil were observed to increase with a decrease in the initial pH of the ammonium sulfate solution. The lead in soil included an acid-extractable fraction, reducible fraction, oxidizable fraction, and a residual fraction, with the predominant fractions being the reducible and acid-extractable fractions. Ninety-six percent of the extractable fraction in soil was desorbed into solution at pH = 3.0, and the content of the reducible fraction was observed to initially increase (when pH >4.0) and then decrease (when pH oxidizable fraction > acid-extractable fraction > residual fraction after the simulating leaching mining process. The change in pH was also found to have a larger influence on the acid-extractable and reducible fractions than the other two fractions. The proportion of the extractable fraction being leached was ca. 86%, and the reducible fraction was enriched along the migration direction of the leaching liquid. These results suggest that certain lead fractions may desorb again and contaminate the environment via acid rain, which provides significant information for environmental assessment and remediation after mining process. Graphical abstract ᅟ.

  8. Neutron Time-of-Flight Quantification of Water Desorption Isotherms of Montmorillonite

    DEFF Research Database (Denmark)

    Gates, Will P.; Bordallo, Heloisa N.; Aldridge, Laurence P.

    2012-01-01

    -montmorillonite (SAz-1) and charge-reduced preparations equilibrated at RH = 33% and 55%, whose gravimetric water contents are in proportion with their layer charge. Quasi-elastic neutron scattering results revealed significant differences within interlayer water populations and between interlayer and interparticle...

  9. Wetland Surface Water Processes

    National Research Council Canada - National Science Library

    1993-01-01

    .... Temporary storage includes channel, overbank, basin, and groundwater storage. Water is removed from the wetland through evaporation, plant transpiration, channel, overland and tidal flow, and groundwater recharge...

  10. Hygroscopic dimensional changes of self-adhering and new resin-matrix composites during water sorption/desorption cycles.

    Science.gov (United States)

    Wei, Yong-jie; Silikas, Nick; Zhang, Zhen-ting; Watts, David C

    2011-03-01

    To study hygroscopic dimensional changes in new resin-matrix composites during water sorption/desorption cycles. Five materials were examined: a self-adhering flowable composite: Vertise® Flow (VF), a universal composite: GC Kalore (GCK), two micro-fine hybrid composites: GC Gradia Direct Anterior (GDA) and GC Gradia Direct Posterior (GDP), and a posterior restorative composite: Filtek® Silorane (FS). Five disk-shaped specimens of each material were prepared (15 mm diameter × 2 mm thickness) according to ISO 4049. The mean diameter of each specimen was measured by a custom-built laser micrometer (to a resolution of 200 nm) periodically over 150d water immersion and 40d recondition periods at (37 ± 1)°C. Perspex controls were used. Data analysis was performed by repeated measures ANOVA, one-way ANOVA and Tukey's post hoc test (phygroscopic expansion were found for all test materials during sorption, ranging from 0.74% (± 0.05) for FS to 4.82% (± 0.13) for VF. The differences were significant for all materials (phygroscopic expansion. The extent of compensation of polymerization shrinkage by hygroscopic expansion depends on materials, specimen dimensions and time-scale. So the clinical situation must be taken into consideration in the application of these findings. Copyright © 2010 Academy of Dental Materials. All rights reserved.

  11. Effects of clay amendment on adsorption and desorption of copper in water repellent soils

    NARCIS (Netherlands)

    Xiong, X.; Stagnitti, F.; Allinson, G.; Turoczy, N.; Li, P.; LeBlanc, M.; Cann, M.A.; Doerr, S.H.; Steenhuis, M.M.; Parlange, J.Y.; Rooij, de G.; Ritsema, C.J.; Dekker, L.W.

    2005-01-01

    Copper is an important micronutrient and trace amounts are essential for crop growth. However, high concentrations of copper will produce toxic effects. Australia is increasingly developing production of crops in water repellent soils. Clay amendment, a common amelioration techniques used in

  12. Erbium hydride thermal desorption : controlling kinetics.

    Energy Technology Data Exchange (ETDEWEB)

    Ferrizz, Robert Matthew

    2007-08-01

    Thermal desorption spectroscopy (TDS) is used to study the decomposition kinetics of erbium hydride thin films. The TDS results presented in this report show that hydride film processing parameters directly impact thermal stability. Issues to be addressed include desorption kinetics for dihydrides and trihydrides, and the effect of film growth parameters, loading parameters, and substrate selection on desorption kinetics.

  13. Effects of aging process on adsorption-desorption and bioavailability of fomesafen in an agricultural soil amended with rice hull biochar.

    Science.gov (United States)

    Khorram, Mahdi Safaei; Lin, Dunli; Zhang, Qian; Zheng, Yuan; Fang, Hua; Yu, Yunlong

    2017-06-01

    Biochar has been introduced as an acceptable soil amendment due to its environmental benefits such as sequestering soil contaminants. However, the aging process in biochar amended soil probably decreases the adsorption capacity of biochar through changing its physico-chemical properties. Adsorption, leaching and bioavailability of fomesafen to corn in a Chinese soil amended by rice hull biochar after 0, 30, 90 and 180days were investigated. Results showed that the addition of 0.5%-2% fresh biochar significantly increases the adsorption of fomesafen 4-26 times compare to unamended soil due to higher SSA of biochar. Biochar amendment also decreases fomesafen concentration in soil pore water by 5%-23% resulting lower risk of the herbicide for cultivated plants. However, the aging process decreased the adsorption capacity of biochar since the adsorption coefficient values which was 1.9-12.4 in 0.5%-2% fresh biochar amended soil, declined to 1.36-4.16, 1.13-2.78 and 0.95-2.31 in 1, 3 and 6-month aged treatments, respectively. Consequently, higher desorption, leaching and bioavailable fraction of fomesafen belonged to 6-month aged treatment. Nevertheless, rice hull biochar was effective for sequestering fomesafen as the adsorption capacity of biochar amended soil after 6months of aging was still 2.5-5 times higher compared to that of unamended soil. Copyright © 2016. Published by Elsevier B.V.

  14. Transient desorption of water vapor - A potential source of error in upper atmosphere rocket experiments

    Science.gov (United States)

    Kendall, B. R. F.; Weeks, J. O.

    1974-01-01

    Results of measurements of the outgassing rates of samples of materials and surface finishes used on the outer skins of rocket-borne experiment packages in simulated rocket ascents. The results showed outgassing rates for anodized aluminum in the second minute of flight which are two to three orders of magnitude higher than those given in typical tables of outgassing rates. The measured rates for aluminum with chromate conversion surface coatings were also abnormally high. These abnormally high initial rates fell quickly after about five to ten minutes to values comparable with those in the published literature. It is concluded that anodized and chromate conversion coatings on the aluminum outer surfaces of a sounding rocket experiment package will cause gross distortion of the true water vapor environment.

  15. Testing of the Effect of Reaction Parameters on the Enzyme Immobilization by Adsorption and Cross-Linking Processes with Kinetic Desorption Method

    Directory of Open Access Journals (Sweden)

    Dániel Radva

    2011-01-01

    Full Text Available The activity of enzymes after the immobilization by weak interactions such as adsorption or adsorption followed by a cross-linking reaction can change easily not only during further application but during the activity measured via desorption and/or inactivation of enzymes. The changes in activity could be a consequence of the interactions between the enzyme and support. In this work a quick and efficient method is developed that permits studying of the strength and properties of the forces between the enzymes and support by examining the kinetics of desorption and/or inactivation. Applying this new cyclic kinetic desorption method, the effect of reaction parameters on immobilization could also be studied. The efficiency of this method was tested for optimizing the parameters for immobilization of β-glucosidase on Amberlite IRA 900 anion exchange resin by an adsorption followed by a cross-linking with glutaraldehyde to form potential preparation for food industry. The following parameters were chosen: concentration (0.10 M of the buffer (sodium acetate, pH=5.5 and the ratio of carrier to enzyme (10:1 for the adsorption step, then the time of treatment (1 min and concentration (0.25, by mass per volume of glutaraldehyde for the cross-linking by using the kinetic desorption method. The activity of this preparation was 57 μmol/(min·g in respect of dry resin. It was established that the effect of different parameters on this enzyme immobilization could be characterized by the new cyclic kinetic desorption method in a quick and efficient way; furthermore, it permitted separate testing of the effect of parameters on the adsorption and cross-linking processes.

  16. Binding energies: New values and impact on the efficiency of chemical desorption

    Science.gov (United States)

    Wakelam, V.; Loison, J.-C.; Mereau, R.; Ruaud, M.

    2017-03-01

    Recent laboratory measurements have confirmed that chemical desorption (desorption of products due to exothermic surface reactions) can be an efficient process. The impact of including this process into gas-grain chemical models entirely depends on the formalism used and the associated parameters. Among these parameters, binding energies are probably the most uncertain ones for the moment. We propose a new model to compute binding energy of species to water ice surfaces. We have also compared the model results using either the new chemical desorption model proposed by Minissale et al. (2016) or the one of Garrod et al. (2007). The new binding energies have a strong impact on the formation of complex organic molecules. In addition, the new chemical desorption model from Minissale produces a much smaller desorption of these species and also of methanol. Combining the two effects, the abundances of CH3OH and COMs observed in cold cores cannot be reproduced by astrochemical models anymore.

  17. Diel biogeochemical processes in terrestrial waters

    Science.gov (United States)

    Compiled and Edited by Nimick, David A.; Gammons, Christopher H.

    2011-01-01

    Many biogeochemical processes in rivers and lakes respond to the solar photocycle and produce persistent patterns of measureable phenomena that exhibit a day-night, or 24-h, cycle. Despite a large body of recent literature, the mechanisms responsible for these diel fluctuations are widely debated, with a growing consensus that combinations of physical, chemical, and biological processes are involved. These processes include streamflow variation, photosynthesis and respiration, plant assimilation, and reactions involving photochemistry, adsorption and desorption, and mineral precipitation and dissolution. Diel changes in streamflow and water properties such as temperature, pH, and dissolved oxygen concentration have been widely recognized, and recently, diel studies have focused more widely by considering other constituents such as dissolved and particulate trace metals, metalloids, rare earth elements, mercury, organic matter, dissolved inorganic carbon (DIC), and nutrients. The details of many diel processes are being studied using stable isotopes, which also can exhibit diel cycles in response to microbial metabolism, photosynthesis and respiration, or changes in phase, speciation, or redox state. In addition, secondary effects that diel cycles might have, for example, on biota or in the hyporheic zone are beginning to be considered. This special issue is composed primarily of papers presented at the topical session "Diurnal Biogeochemical Processes in Rivers, Lakes, and Shallow Groundwater" held at the annual meeting of the Geological Society of America in October 2009 in Portland, Oregon. This session was organized because many of the growing number of diel studies have addressed just a small part of the full range of diel cycling phenomena found in rivers and lakes. This limited focus is understandable because (1) fundamental aspects of many diel processes are poorly understood and require detailed study, (2) the interests and expertise of individual

  18. Assessing the Interplay between the Physicochemical Parameters of Ion-Pairing Reagents and the Analyte Sequence on the Electrospray Desorption Process for Oligonucleotides

    Science.gov (United States)

    Basiri, Babak; Murph, Mandi M.; Bartlett, Michael G.

    2017-08-01

    Alkylamines are widely used as ion-pairing agents during LC-MS of oligonucleotides. In addition to a better chromatographic separation, they also assist with the desorption of oligonucleotide ions into the gas phase, cause charge state reduction, and decrease cation adduction. However, the choice of such ion-pairing agents has considerable influence on the MS signal intensity of oligonucleotides as they can also cause significant ion suppression. Interestingly, optimal ion-pairing agents should be selected on a case by case basis as their choice is strongly influenced by the sequence of the oligonucleotide under investigation. Despite imposing major practical difficulties to analytical method development, such a highly variable system that responds very strongly to the nuances of the electrospray composition provides an excellent opportunity for a fundamental study of the electrospray ionization process. Our investigations using this system quantitatively revealed the major factors that influenced the ESI ionization efficiency of oligonucleotides. Parameters such as boiling point, proton affinity, partition coefficient, water solubility, and Henry's law constants for the ion-pairing reagents and the hydrophobic thymine content of the oligonucleotides were found to be the most significant contributors. Identification of these parameters also allowed for the development of a statistical predictive algorithm that can assist with the choice of an optimum IP agent for each particular oligonucleotide sequence. We believe that research in the field of oligonucleotide bioanalysis will significantly benefit from this algorithm (included in Supplementary Material) as it advocates for the use of lesser-known but more suitable ion-pair alternatives to TEA for many oligonucleotide sequences.

  19. Very-large-volume sampling of water in gas chromatography using the through oven transfer adsorption desorption (TOTAD) interface for pesticide-residue analysis.

    Science.gov (United States)

    Alario, J; Perez, M; Vazquez, A; Villén, J

    2001-02-01

    The Through Oven Transfer Adsorption Desorption (TOTAD) interface is used to directly introduce large volumes of water (1 mL or more) into a capillary gas chromatograph. The TOTAD interface is a greatly modified programmed temperature vaporizer injector incorporating changes that affect the pneumatics, sample introduction, solvent elimination, and operation mode. The system can easily be automated. The technique is applied to the analysis of pesticide residue in standard solutions and real water samples from the Ebro River (northeastern Spain). The speed of sample introduction was 1 mL/min, and the solvent elimination was almost complete. A nitrogen phosphorous detector is used, and the relative standard deviation varied from 5.7% to 11.7% for the absolute peak areas. The sensitivity achieved by introducing 1 mL of the sample is sufficient for most pesticide-residue analyses in water. The limits of detection ranged from 0.5 to 8.1 ng/L.

  20. Adsorption, Desorption, Surface Diffusion, Lattice Defect Formation, and Kink Incorporation Processes of Particles on Growth Interfaces of Colloidal Crystals with Attractive Interactions

    Directory of Open Access Journals (Sweden)

    Yoshihisa Suzuki

    2016-07-01

    Full Text Available Good model systems are required in order to understand crystal growth processes because, in many cases, precise incorporation processes of atoms or molecules cannot be visualized easily at the atomic or molecular level. Using a transmission-type optical microscope, we have successfully observed in situ adsorption, desorption, surface diffusion, lattice defect formation, and kink incorporation of particles on growth interfaces of colloidal crystals of polystyrene particles in aqueous sodium polyacrylate solutions. Precise surface transportation and kink incorporation processes of the particles into the colloidal crystals with attractive interactions were observed in situ at the particle level. In particular, contrary to the conventional expectations, the diffusion of particles along steps around a two-dimensional island of the growth interface was not the main route for kink incorporation. This is probably due to the number of bonds between adsorbed particles and particles in a crystal; the number exceeds the limit at which a particle easily exchanges its position to the adjacent one along the step. We also found novel desorption processes of particles from steps to terraces, attributing them to the assistance of attractive forces from additionally adsorbing particles to the particles on the steps.

  1. A Compact, Solid-State UV (266 nm) Laser System Capable of Burst-Mode Operation for Laser Ablation Desorption Processing

    Science.gov (United States)

    Arevalo, Ricardo, Jr.; Coyle, Barry; Paulios, Demetrios; Stysley, Paul; Feng, Steve; Getty, Stephanie; Binkerhoff, William

    2015-01-01

    Compared to wet chemistry and pyrolysis techniques, in situ laser-based methods of chemical analysis provide an ideal way to characterize precious planetary materials without requiring extensive sample processing. In particular, laser desorption and ablation techniques allow for rapid, reproducible and robust data acquisition over a wide mass range, plus: Quantitative, spatially-resolved measurements of elemental and molecular (organic and inorganic) abundances; Low analytical blanks and limits-of-detection ( ng g-1); and, the destruction of minimal quantities of sample ( g) compared to traditional solution and/or pyrolysis analyses (mg).

  2. Novel Molecular Spectroscopic Multimethod Approach for Monitoring Water Absorption/Desorption Kinetics of CAD/CAM Poly(Methyl Methacrylate) Prosthodontics.

    Science.gov (United States)

    Wiedemair, Verena; Mayr, Sophia; Wimmer, Daniel S; Köck, Eva Maria; Penner, Simon; Kerstan, Andreas; Steinmassl, Patricia-Anca; Dumfahrt, Herbert; Huck, Christian W

    2017-07-01

    Water absorbed to poly(methyl methacrylate) (PMMA)-based CAD/CAM (computer-assisted design/computer-assisted manufacturing) prosthodontics can alter their properties including hardness and stability. In the present contribution, water absorption and desorption kinetics under defined experimental conditions were monitored employing several supplementary and advanced Fourier transform infrared (FT-IR) spectroscopic techniques in combination with multivariate analysis (MVA). In this synergistic vibrational spectroscopic multimethod approach, first a novel near-infrared (NIR) diffuse fiber optic probe reflection spectroscopic method was established for time-resolved analysis of water uptake within seven days under controlled conditions. Near-infrared water absorbance spectra in a wavenumber range between 5288-5100 cm-1 (combination band) and 5424-5352 cm-1 (second overtone) were used establishing corresponding calibration and validation models to quantify the amount of water in the milligram range. Therefore, 14 well-defined samples exposed to prior optimized experimental conditions were taken into consideration. The average daily water uptake conducting reference analysis was calculated as 22 mg/day for one week. Additionally, in this study for the first time NIR two-dimensional correlation spectroscopy (2D-COS) was conducted to monitor and interpret the spectral dynamics of water absorption on the prosthodontics in a wavenumber range of 5100-5300 cm-1. For sensitive time-resolved recording of water desorption, a recently developed high-temperature, high-pressure FT-IR reaction cell with water-free ultra-dry in situ and operando operation was applied. The reaction cell, as well as the sample holder, was fully made of quartz glass, with no hot metal or ceramic parts in the vicinity of the high temperature zone. Applying a temperature gradient in the range of 25-150 ℃, mid-infrared (MIR) 2D-COS was successfully conducted to get insights into the dynamic

  3. Use of matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectrometry for bacterial monitoring in routine analysis at a drinking water treatment plant.

    Science.gov (United States)

    Sala-Comorera, Laura; Vilaró, Carles; Galofré, Belén; Blanch, Anicet R; García-Aljaro, Cristina

    2016-10-01

    The study of bacterial communities throughout a drinking water treatment plant could provide a basic understanding of the effects of water processing that could then be used to improve the management of such plants. However, it is necessary to develop new analytical techniques that are sufficiently efficient, robust and fast for their effective and useful application in routine analysis. The aim of this study is therefore to assess the performance of matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS), as compared to the PhenePlate™ system, for routine analysis in a drinking water treatment plant. To this end we studied a total of 277 colonies isolated in different seasons and from different points throughout the water treatment process, including: raw water, sand filtration, ultrafiltration, reverse osmosis and chlorination. The colonies were analysed using MALDI-TOF MS by direct deposition of the cells on the plate. The colonies were also biochemically fingerprinted using the PhenePlate™ system, clustered according to their similarity and a representative strain was selected for 16S rRNA gene sequencing and API® gallery-based identification. The use of MALDI-TOF MS was reliable compared to the PhenePlate™ system and has the advantage of being faster and relatively cheap. Bacteria typing by MALDI-TOF MS is therefore a promising method to replace conventional routine phenotypic methods for the identification of bacteria in drinking water laboratories, thanks to its robustness. The major limiting factor for MALDI-TOF MS is the lack of a suitable mass spectra database; although each laboratory can develop its own library. This methodology will provide a tracking tool for companies to use in risk management and the detection of possible failures in both the water treatment processes and the distribution network, as well as offering characterization of the intrinsic microbial populations. Copyright © 2016 Elsevier Gmb

  4. Hysteretic characteristics of 1/λ⁴ scattering of light during adsorption and desorption of water in porous Vycor glass with nanopores.

    Science.gov (United States)

    Ogawa, Shigeo; Nakamura, Jiro

    2013-10-01

    Porous Vycor glass with nanopores is transparent in the visible region and is often used in colorimetric chemical sensing when impregnated with selectively reacting reagents. However, it has some disadvantages in sensing, since changes in the humidity of ambient air strongly affect its transmission. In this work, by combining a humidity-controlled thermostatic chamber and an ultraviolet-visible and near-infrared spectrophotometer through fiber optics, we analyzed the effect of increasing and decreasing humidity in the ambient air on the transparency change of the nanoporous glass. The transparency response in the visible region to changes in humidity is analyzed to correlate the turbidity response of the glass with the amount of water in it. The turbidity is found to be dependent on the inverse fourth power of the wavelength (1/λ⁴), which implies that Rayleigh-type scattering takes place for both adsorption and desorption of water. We show that measures of the extent of the optical inhomogeneity that causes the scattering, such as the effective radius of scatterers and their number density, exhibit a pronounced hysteretic characteristic for the imbibition and drainage of water, while the absorption inherent to imbibed water also shows another type of hysteresis that is quite similar to the sorption isotherms of water. On the basis of the above observations, we show that the transitory white turbidity of nanoporous glasses during changes in humidity can be consistently interpreted and quantitatively analyzed by a simple Rayleigh scattering mechanism.

  5. Determination of short chain chlorinated paraffins in water by stir bar sorptive extraction-thermal desorption-gas chromatography-triple quadrupole tandem mass spectrometry.

    Science.gov (United States)

    Tölgyessy, P; Nagyová, S; Sládkovičová, M

    2017-04-21

    A simple, robust, sensitive and environment friendly method for the determination of short chain chlorinated paraffins (SCCPs) in water using stir bar sorptive extraction (SBSE) coupled to thermal desorption-gas chromatography-triple quadrupole tandem mass spectrometry (TD-GC-QqQ-MS/MS) was developed. SBSE was performed using 100mL of water sample, 20mL of methanol as a modifier, and a commercial sorptive stir bar (with 10mm×0.5mm PDMS layer) during extraction period of 16h. After extraction, the sorptive stir bar was thermally desorbed and online analysed by GC-MS/MS. Method performance was evaluated for MilliQ and surface water spiked samples. For both types of matrices, a linear dynamic range of 0.5-3.0μgL -1 with correlation coefficients >0.999 and relative standard deviations (RSDs) of the relative response factors (RRFs) <12% was established. The limits of quantification (LOQs) of 0.06 and 0.08μgL -1 , and the precision (repeatability) of 6.4 and 7.7% (RSDs) were achieved for MilliQ and surface water, respectively. The method also showed good robustness, recovery and accuracy. The obtained performance characteristics indicate that the method is suitable for screening and monitoring and compliance checking with environmental quality standards (EQS, set by the EU) for SCCPs in surface waters. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. CO Diffusion and Desorption Kinetics in CO2 Ices

    Science.gov (United States)

    Cooke, Ilsa R.; Öberg, Karin I.; Fayolle, Edith C.; Peeler, Zoe; Bergner, Jennifer B.

    2018-01-01

    The diffusion of species in icy dust grain mantles is a fundamental process that shapes the chemistry of interstellar regions; yet, measurements of diffusion in interstellar ice analogs are scarce. Here we present measurements of CO diffusion into CO2 ice at low temperatures (T = 11–23 K) using CO2 longitudinal optical phonon modes to monitor the level of mixing of initially layered ices. We model the diffusion kinetics using Fick’s second law and find that the temperature-dependent diffusion coefficients are well fit by an Arrhenius equation, giving a diffusion barrier of 300 ± 40 K. The low barrier along with the diffusion kinetics through isotopically labeled layers suggest that CO diffuses through CO2 along pore surfaces rather than through bulk diffusion. In complementary experiments, we measure the desorption energy of CO from CO2 ices deposited at 11–50 K by temperature programmed desorption and find that the desorption barrier ranges from 1240 ± 90 K to 1410 ± 70 K depending on the CO2 deposition temperature and resultant ice porosity. The measured CO–CO2 desorption barriers demonstrate that CO binds equally well to CO2 and H2O ices when both are compact. The CO–CO2 diffusion–desorption barrier ratio ranges from 0.21 to 0.24 dependent on the binding environment during diffusion. The diffusion–desorption ratio is consistent with the above hypothesis that the observed diffusion is a surface process and adds to previous experimental evidence on diffusion in water ice that suggests surface diffusion is important to the mobility of molecules within interstellar ices.

  7. Trace analysis of phenolic xenoestrogens in water samples by stir bar sorptive extraction with in situ derivatization and thermal desorption-gas chromatography-mass spectrometry.

    Science.gov (United States)

    Kawaguchi, Migaku; Inoue, Koichi; Yoshimura, Mariko; Sakui, Norihiro; Okanouchi, Noriya; Ito, Rie; Yoshimura, Yoshihiro; Nakazawa, Hiroyuki

    2004-07-02

    A method for the simultaneous measurement of trace amounts of phenolic xenoestrogens, such as 2,4-dichlorophenol (2,4-DCP), 4-tert-butyl-phenol (BP), 4-tert-octylphenol (OP), 4-nonylphenol (NP), pentachlorophenol (PCP) and bisphenol A (BPA), in water samples was developed using stir bar sorptive extraction (SBSE) with in situ derivatization followed by thermal desorption (TD)-gas chromatography-mass spectrometry (GC-MS) analysis. The conditions for derivatization with acetic acid anhydride were investigated. A polydimethylsiloxane (PDMS)-coated stir bar and derivatization reagents were added to 10 ml of water sample and stirring was commenced for 10-180 min at room temperature (25 degrees C) in a headspace vial. Then, the extract was analyzed by TD-GC-MS. The optimum time for SBSE with in situ derivatization was 90 min. The detection limits of 2,4-DCP, BP, OP, NP, PCP and BPA were 2, 1, 0.5, 5, 2 and 2 pg ml(-1), respectively. The method showed good linearity over the concentration ranges of 10, 5, 2, 20, 10 and 10-1000 pg ml(-1) for 2,4-DCP, BP, OP, NP, PCP and BPA, respectively, and the correlation coefficients were higher than 0.99. The average recoveries of those compounds in river water samples were equal to or higher than 93.9% (R.S.D. river water samples.

  8. Heat-integrated liquid-desorption exchanger (HILDE) for CO2 desorption

    NARCIS (Netherlands)

    Ham, L.V. van der; Khakharia, P.M.; Goetheer, E.L.V.

    2016-01-01

    A novel type of separating heat exchanger, called a heat-integrated liquid-desorption exchanger (HILDE), applied to a typical CO2 desorption process, has been investigated both numerically and experimentally. Process simulations, hydrodynamic and mass transfer experiments, and a preliminary cost

  9. Technetium, Iodine, and Chromium Adsorption/Desorption Kd Values for Vadose Zone Pore Water, ILAW Glass, and Cast Stone Leachates Contacting an IDF Sand Sequence

    Energy Technology Data Exchange (ETDEWEB)

    Last, George V. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Snyder, Michelle M.V. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Um, Wooyong [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Stephenson, John R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Leavy, Ian I. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Strickland, Christopher E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Bacon, Diana H. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Qafoku, Nikolla [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Serne, R. Jeffrey [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2015-11-01

    Performance and risk assessments of immobilized low-activity waste (ILAW) at the Integrated Disposal Facility (IDF) have shown that risks to groundwater are quite sensitive to adsorption-desorption interactions occurring in the near- and far-field environment. These interactions between the underlying sediments and the contaminants present in the leachates that descend from the buried glass, secondary waste grouts, and potentially Cast Stone low-activity waste packages have been represented in these assessments using the contaminant distribution coefficient (Kd) construct. Some contaminants (99Tc, 129I, and Cr) present in significant quantities in these wastes have low Kd values and tend to drive risk to public health and the environment. Relatively small changes in the Kd value can cause relatively large changes in the retardation factor. Thus, even relatively small uncertainty in the Kd value can result in a relatively large uncertainty in the risk determined through performance assessment modeling. The purpose of this study is to further reduce the uncertainty in Kd values for 99Tc, iodine (iodide and iodate), and Cr (chromate; CrO42-) by conducting systematic adsorption-desorption experiments using actual sand-dominated Hanford formation sediments from beneath the IDF and solutions that closely mimic Hanford vadose zone pore water and leachates from Cast Stone and ILAW glass waste forms. Twenty-four batch and 21 flow-through column experiments were conducted, yielding 261 Kd measurements for these key contaminants, and contributing to our understanding for predicting transport from wastes disposed to the IDF. While the batch Kd methodology is not well-suited for measuring Kd values for non-sorbing species (as noted by the U.S. Environmental Protection Agency), the batch Kd results presented here are not wholly inconsistent with the column Kd results, and could be used for sensitivity purposes. Results from the column experiments are consistent with the best

  10. The relationship between cyclic hygroscopic dimensional changes and water sorption/desorption of self-adhering and new resin-matrix composites.

    Science.gov (United States)

    Wei, Yong-Jie; Silikas, Nick; Zhang, Zhen-Ting; Watts, David C

    2013-09-01

    This study evaluated the relationship between mass changes and hygroscopic dimensional changes during water sorption/desorption cycles in new resin composites. A silorane posterior composite (Filtek(®) Silorane, FS), two micro-fine hybrid composites (GC Gradia Direct Anterior, GDA; GC Gradia Direct Posterior, GDP), a universal composite (GC Kalore, GCK), and a self-adhering flowable composite (Vertise(®) Flow, VF) were evaluated. 25 (n=5) disk specimens (15mm×2mm) were prepared according to ISO 4049. Water sorption was measured gravimetrically. Hygroscopic expansions were measured by a laser micrometer regularly during 150 d water storage and 40 d recondition periods, all at 37°C. Data were analyzed by repeated measures ANOVA, one-way ANOVA and Tukey's post hoc test (phygroscopic expansions were from 0.74% (±0.05) for FS to 4.79% (±0.18) for VF. The differences were significant for all materials (phygroscopic changes between GCK and GDA. The relationship between hygroscopic expansions and mass changes was initially non-linear and then tended toward linear behavior. But at the late stage of water sorption the hygroscopic expansion of GCK and VF was slightly sigmoidal with respect to their mass changes. Relationships between hygroscopic expansion and mass change were determined for some diverse resin-matrix composites. The initial non-linearity for all materials suggests a lower expansion rate due to occupancy of internal free volume by water ingress. The silorane composite FS showed statistically the lowest mass change and hygroscopic dimensional change. Copyright © 2013 Academy of Dental Materials. All rights reserved.

  11. Water surface capturing by image processing

    Science.gov (United States)

    An alternative means of measuring the water surface interface during laboratory experiments is processing a series of sequentially captured images. Image processing can provide a continuous, non-intrusive record of the water surface profile whose accuracy is not dependent on water depth. More trad...

  12. Co2 desorption from glycerol for reusable absorbent

    Science.gov (United States)

    Mindaryani, Aswati; Budhijanto, Wiratni; Narendratama, Roberto Delta

    2017-05-01

    Increasing demand of energy forces human to develop new energy sources. Biogas comes as a reliable option of sustainable energy fulfilment. Biogas consists of methane and some impurities such as CO2 and H2S. CO2 removal from biogas guarantees an elevation of biogas heating value. CO2 removal can be achieved by integrated absorption-desorption process using certain absorbent. Regeneration of absorbent is a necessity to recover CO2 absorption capability of used absorbent. This paper focuses on the study of CO2 desorption from glycerol absorbent using N2 as stripping gas. Effect of desorption temperature and N2 flow rate is studied. Three neck flask equipped with water bath is filled with 750 mL of glycerol. Waterbath temperature is set at 40°C. Absorption starts with flowing 1 LPM gas mixture of 40% CO2 to absorbent through sparger. CO2 concentration of outlet gas is analyzed using gas chromatograph every 10 seconds. Gas flow is stopped when outlet CO2 concentration reaches inlet concentration. Desorption process is conducted as follows, 0.1 LPM nitrogen is flowed through sparger to absorber. Samples of outlet gas are taken at several time. Samples are analyzed with gas chromatograph. The same experiments are conducted for temperature variation of 60°C and 80°C and nitrogen flow rate variation of 0.2 LPM and 0.3 LPM. The model of batch desorption process by gas stripping is developed. Mass transfer coefficient was determined by curve fitting. Result shows a noticeable increase of desorbed CO2 with increasing of temperature and N2 flow rate.

  13. Numerical simulation study of fracturing wells for shale gas with gas–water two-phase flow system under desorption and diffusion conditions

    Directory of Open Access Journals (Sweden)

    Jinzhou Zhao

    2016-06-01

    Full Text Available Hydraulic fracturing is an essential technology in developing shale gas reservoirs, not to mention, accurate prediction of productivity in fractured shale gas wells is the foundation of an efficient development in shale gas reservoirs. This paper establishes a gas–water two-phase flow percolation mathematical model by a determined numerical simulation and calculation method under desorption and diffusion conditions. By means of simulating for a post-frac performance of the shale gas reservoir, this paper devotes to a quantitative analysis the impact of fracture parameters, physical parameters, and desorption–diffusion parameters. The outcome of this research indicates that hydraulic fracturing can improve single well production and it's an effective measure in the development of shale gas. The conductivity of hydraulic fractures and the permeability of natural fractures are the main influences on shale gas production. The higher these factors are, the higher the gas and water productions are. In comparison, the matrix permeability and diffusion coefficients have minimal influences on production.

  14. Mechanism of the Two-Phase Flow Model for Water and Gas Based on Adsorption and Desorption in Fractured Coal and Rock

    Science.gov (United States)

    Chen, Shikuo; Yang, Tianhong; Ranjith, P. G.; Wei, Chenhui

    2017-03-01

    Coalbed methane (CBM) is an important high-efficiency, clean-energy raw material with immense potential for application; however, its occurrence in low-permeability reservoirs limits its application. Hydraulic fracturing has been used in low-permeability CBM exploration and as a new technique for preventing gas hazards in coal mines. Fractures are the main pathways of fluid accumulation and migration, and they exert some control over the stability of rock mass. However, the differences in progression between the original fractures of the coal mass and the new discrete fractures caused by hydraulic fracturing remain unclear, and the unsaturated seepage flows require further study. Therefore, a cross-scale hydraulic fractured rock mass numerical model was developed by using the 3D fractured extrusion coupling variables reconstruction technique. This paper uses fracture surface parameters combined with the fractal dimension and multi-medium theory to provide a high-precision characterization and interpretation of the fracture mechanics. The mechanism of the permeability evolution of fractured coal and rock under stress-releasing mining combined with water injection was studied by considering gas adsorption and desorption as well as the coupling characteristic of seepage-stress in fractured rock masses. Aperture, contact area ratio, and stress in permeability and fracture development have a strong influence on the permeability and seepage path, which in turn control the effective radius by absolute water injection. All of these factors should be considered when studying the structural characteristics of rock masses.

  15. Ionomer-Membrane Water Processing Apparatus

    Science.gov (United States)

    MacCallum, Taber K. (Inventor); Kelsey, Laura Katrina (Inventor)

    2017-01-01

    This disclosure provides water processing apparatuses, systems, and methods for recovering water from wastewater such as urine. The water processing apparatuses, systems, and methods can utilize membrane technology for extracting purified water in a single step. A containment unit can include an ionomer membrane, such as Nafion.RTM., over a hydrophobic microporous membrane, such as polytetrafluoroethylene (PTFE). The containment unit can be filled with wastewater, and the hydrophobic microporous membrane can be impermeable to liquids and solids of the wastewater but permeable to gases and vapors of the wastewater, and the ionomer membrane can be permeable to water vapor but impermeable to one or more contaminants of the gases and vapors. The containment unit can be exposed to a dry purge gas to maintain a water vapor partial pressure differential to drive permeation of the water vapor, and the water vapor can be collected and processed into potable water.

  16. Ionomer-Membrane Water Processing Methods

    Science.gov (United States)

    MacCallum, Taber K. (Inventor); Kelsey, Laura (Inventor)

    2016-01-01

    This disclosure provides water processing apparatuses, systems, and methods for recovering water from wastewater such as urine. The water processing apparatuses, systems, and methods can utilize membrane technology for extracting purified water in a single step. A containment unit can include an ionomer membrane, such as Nafion(TradeMark) over a hydrophobic microporous membrane, such as polytetrafluoroethylene (PTFE). The containment unit can be filled with wastewater, and the hydrophobic microporous membrane can be impermeable to liquids and solids of the wastewater but permeable to gases and vapors of the wastewater, and the ionomer membrane can be permeable to water vapor but impermeable to one or more contaminants of the gases and vapors. The containment unit can be exposed to a dry purge gas to maintain a water vapor partial pressure differential to drive permeation of the water vapor, and the water vapor can be collected and processed into potable water.

  17. Ionomer-Membrane Water Processing Apparatus

    Science.gov (United States)

    MacCallum, Taber K. (Inventor); Kelsey, Laura (Inventor)

    2016-01-01

    This disclosure provides water processing apparatuses, systems, and methods for recovering water from wastewater such as urine. The water processing apparatuses, systems, and methods can utilize membrane technology for extracting purified water in a single step. A containment unit can include an ionomer membrane, such as Nafion(Registered Trademark), over a hydrophobic microporous membrane, such as polytetrafluoroethylene (PTFE). The containment unit can be filled with wastewater, and the hydrophobic microporous membrane can be impermeable to liquids and solids of the wastewater but permeable to gases and vapors of the wastewater, and the ionomer membrane can be permeable to water vapor but impermeable to one or more contaminants of the gases and vapors. The containment unit can be exposed to a dry purge gas to maintain a water vapor partial pressure differential to drive permeation of the water vapor, and the water vapor can be collected and processed into potable water.

  18. Site-specific binding of a water molecule to the sulfa drugs sulfamethoxazole and sulfisoxazole: a laser-desorption isomer-specific UV and IR study.

    Science.gov (United States)

    Uhlemann, Thomas; Seidel, Sebastian; Müller, Christian W

    2018-02-20

    To determine the preferred water molecule binding sites of the polybasic sulfa drugs sulfamethoxazole (SMX) and sulfisoxazole (SIX), we have studied their monomers and monohydrated complexes through laser-desorption conformer-specific UV and IR spectroscopy. Both the SMX and SIX monomer adopt a single conformer in the molecular beam. On the basis of their conformer-specific IR spectra in the NH stretch region, these conformers were assigned to the SMX and SIX global minimum structures, both exhibiting a staggered sulfonamide group and an intramolecular C-HO[double bond, length as m-dash]S hydrogen bond. The SMX-H 2 O and SIX-H 2 O complexes each adopt a single isomer in the molecular beam. Their isomeric structures were determined based on their isomer-specific IR spectra in the NH/OH stretch region. Quantum Theory of Atoms in Molecules analysis of the calculated electron densities revealed that in the SMX-H 2 O complex the water molecule donates an O-HN hydrogen bond to the heterocycle nitrogen atom and accepts an N-HO hydrogen bond from the sulfonamide NH group. In the SIX-H 2 O complex, however, the water molecule does not bind to the heterocycle but instead donates an O-HO[double bond, length as m-dash]S hydrogen bond to the sulfonamide group and accepts an N-HO hydrogen bond from the sulfonamide NH group. Both water complexes are additionally stabilized by a C ph -HOH 2 hydrogen bond. Interacting Quantum Atoms analysis suggests that all intermolecular hydrogen bonds are dominated by the short-range exchange-correlation contribution.

  19. Molecular Modeling of Chem-Bio (CB) Contaminant Sorption/Desorption and Reactions in Chlorinated Water Systems

    Science.gov (United States)

    2012-05-01

    investigation of the behavior of the OP-hydroxyl interactions was undertaken using the Polarizable Continuum Model ( PCM ) to simulate liquid water implicitly...through a regimen of simulations, where it was first simulated at high temperatures (7000 K) and gradually cooled to room temperature. Coordinates...1 CHARMM is a versatile and widely used molecular simulation program with broad application to many- particle systems

  20. Thermoresponsive Poly(Ionic Liquid)s in Aqueous Salt Solutions: Salting-Out Effect on Their Phase Behavior and Water Absorption/Desorption Properties.

    Science.gov (United States)

    Okafuji, Akiyoshi; Kohno, Yuki; Ohno, Hiroyuki

    2016-07-01

    Here, a thermoresponsive phase behavior of polymerized ionic liquids (PILs) composed of poly([tri-n-alkyl(vinylbenzyl)phosphonium]chloride) (poly([Pnnn VB ]Cl) is reported, where n (the number of carbon atoms of an alkyl chain) = 4, 5, or 6 after mixing with aqueous sodium chloride solutions. Both monomeric [P555VB ]Cl and the resulting poly([P555VB ]Cl) linear homopolymer show a lower critical solution temperature (LCST)-type phase behavior in aq. NaCl solutions. The phase transition temperature of the PIL shifts to lower value by increasing concentration of NaCl. Also the swelling degree of cross-linked poly([P555VB ]Cl) gel decreases by increasing NaCl concentration, clearly suggesting the "salting-out" effect of NaCl results in a significant dehydration of the poly([P555VB ]Cl) gel. The absorbed water in the PIL gel is desorbed by moderate heating via the LCST behavior, and the absolute absorption/desorption amount is improved by copolymerization of [P555VB ]Cl with more hydrophilic [P444VB ]Cl monomer. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Thermodynamics of the CO2–Absorption/Desorption Section in the Integrated Gasifying Combined Cycle — I. modeling

    Directory of Open Access Journals (Sweden)

    Jaroslav KOZACZKA

    2012-06-01

    Full Text Available The carbon dioxide absorption/desorption unit of the Integrated Gasifying Combined Cycle has been detailed described to formulate appropriate model equations for the processes, suitable for further thermodynamic analyzes. There are two principal technologies of the CO2–removing section, namely the absorption with the following expanding desorption process, and the absorption with the following classical plates (or packing desorption one. The physics of thermodynamic properties of the water/carbon dioxide solution have been presented thoroughly using hitherto literature data. The Henry's Law has been emphasized as the base for further thermodynamic analyzes. The numerical results of appropriate absorption/desorption units have been compiled presuming fundamental relations, which are also presented. They should be the base for their thermodynamic analyzes.

  2. [Study on water processing conditions of Realgar].

    Science.gov (United States)

    Jiang, Hong; Ding, Jing-hua; Zhang, Ying-hua; Shi, Song-tian; Gao, Shuang; Gong, Hui-zhi; Sun, Gui-fan

    2009-01-01

    To optimize the water processing (shui-fei) condition of Realgar. The processing conditions were optimized by L9 (3)4 orthogonal design with three factors as water dose, process times and dryness temperature. The content of dissolved arsenic As(III) in Realgar was tested by High Performance Liquid Chromatography-hydride generation on-line coupled with atomic fluorescence spectrometry (HPLC-HG-AFS). The optimized conditions were 15 times quantity of water, 8 times for processing and dryness temperature of 40 degrees C. The method is accurate and effective,which can be used to evaluate the quality of processed products of Realgar.

  3. Water retention in mushroom during sustainable processing

    OpenAIRE

    Paudel, E.

    2015-01-01

    This thesis deals with the understanding of the water holding capacity of mushroom, in the context of a redesign of their industrial processing. For designing food process the retention of food quality is of the utmost importance. Water holding capacity is an important quality aspect of mushrooms. A convenient process design methodology which accounts also for product quality is Conceptual Process Design (CPD). An approach to follow CPD methodology is first to explore, the material properties...

  4. Infrared matrix-assisted laser desorption/ionization orthogonal-time-of-flight mass spectrometry employing a cooling stage and water ice as a matrix.

    Science.gov (United States)

    Pirkl, Alexander; Soltwisch, Jens; Draude, Felix; Dreisewerd, Klaus

    2012-07-03

    Although water ice has been utilized in the past as a matrix for infrared matrix-assisted laser desorption/ionization mass spectrometry (IR-MALDI-MS), it has not found a wider use due to limitations in the analytical performance and technical demands on the employment of the necessary cooling stage. Here, we developed a temperature-controlled sample stage for use with an orthogonal time-of-flight mass spectrometer (MALDI-o-TOF-MS). The stage utilizes a combination of liquid nitrogen cooling and counterheating with a Peltier element. It allows adjustment of the sample temperature between ~-120 °C and room temperature. To identify optimal irradiation conditions for IR-MALDI with the water ice matrix, we first investigated the influence of excitation wavelength, varied between 2.7 and 3.1 μm, and laser fluence on the signal intensities of molecular substance P ions. These data suggest the involvement of transient melting of the ice during the laser pulse and primary energy deposition into liquid water. As a consequence, the best analytical performance is obtained at a wavelength corresponding to the absorption maximum of liquid water of about 2.94 μm. The current data significantly surpass the previously reported analytical features. The particular softness of the method is, for example, exemplified by the analysis of noncovalently bound holo-myoglobin and of ribonuclease B. This is also the first report demonstrating the analysis of an IgG monoclonal antibody (MW ~ 150 kDa) from a water ice matrix. Untypical for MALDI-MS, high charge states of multiply protonated species were moreover observed for some of the investigated peptides and even for lacto-N-fucopentaose II oligosaccharides. Using water ice as matrix is of particular interest for MALDI MS profiling and imaging applications since matrix-free spectra are produced. The MS and tandem MS analysis of metabolites directly from frozen food samples is demonstrated with the example of a strawberry fruit.

  5. Water retention in mushroom during sustainable processing

    NARCIS (Netherlands)

    Paudel, E.

    2015-01-01

    This thesis deals with the understanding of the water holding capacity of mushroom, in the context of a redesign of their industrial processing. For designing food process the retention of food quality is of the utmost importance. Water holding capacity is an important quality aspect of mushrooms. A

  6. Heterotrophic monitoring at a drinking water treatment plant by matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectrometry after different drinking water treatments.

    Science.gov (United States)

    Sala-Comorera, Laura; Blanch, Anicet R; Vilaró, Carles; Galofré, Belén; García-Aljaro, Cristina

    2017-10-01

    The aim of this work was to assess the suitability of matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) for routine heterotrophic monitoring in a drinking water treatment plant. Water samples were collected from raw surface water and after different treatments during two campaigns over a 1-year period. Heterotrophic bacteria were studied and isolates were identified by MALDI-TOF MS. Moreover, the diversity index and the coefficient of population similarity were also calculated using biochemical fingerprinting of the populations studied. MALDI-TOF MS enabled us to characterize and detect changes in the bacterial community composition throughout the water treatment plant. Raw water showed a large and diverse population which was slightly modified after initial treatment steps (sand filtration and ultrafiltration). Reverse osmosis had a significant impact on the microbial diversity, while the final chlorination step produced a shift in the composition of the bacterial community. Although MALDI-TOF MS could not identify all the isolates since the available MALDI-TOF MS database does not cover all the bacterial diversity in water, this technique could be used to monitor bacterial changes in drinking water treatment plants by creating a specific protein profile database for tracking purposes.

  7. Thermal desorption of methanol in hot cores. Study with a quartz crystal microbalance

    Science.gov (United States)

    Luna, Ramón; Satorre, Miguel Ángel; Domingo, Manuel; Millán, Carlos; Luna-Ferrándiz, Ramón; Gisbert, Georgina; Santonja, Carmina

    2018-01-01

    The desorption process of methanol in the hot cores of massive young stars is addressed in this work. The study of pure methanol ice and when it is mixed or layered with water allows a better understanding of the physical and chemical processes which could have occurred during the formation of methanol and it is possible to infer the range of temperatures within which methanol can be found in the gas phase in these scenarios. The goal of this study was to model the desorption process of methanol as pure ice and mixed or layered with water under the conditions present in the early stages of hot cores whichcharacterize young star formation. The simulations of desorption of methanol, when it stands alone, performed in this work were compared to the values obtained by other authors to validate the method presented. In this work, the desorption of a water:methanol mixture under astrophysical conditions is also simulated. The theoretical results obtained for layered mixtures match with the temperatures at which an increase of the presence of methanol in the gas phase is detected when young massive mass stars are observed. This study has been performed using the frequency variation of a quartz crystal microbalance which provides a direct measure of the desorbing molecules during the experiments. This process was modelled using the Polanyi-Wigner equation and applied to astrophysical scenarios.

  8. Batch sorption-desorption of As(III) from waste water by magnetic palm kernel shell activated carbon using optimized Box-Behnken design

    Science.gov (United States)

    Anyika, Chinedum; Asri, Nur Asilayana Mohd; Majid, Zaiton Abdul; Jaafar, Jafariah; Yahya, Adibah

    2017-09-01

    In this study, we converted activated carbon (AC) into magnetic activated carbon (MAC), which was established to have removed arsenic (III) from wastewater. Arsenic (III) is a toxic heavy metal which is readily soluble in water and can be detrimental to human health. The MAC was prepared by incorporating Fe3O4 into the AC by using Fe3O4 extracted from a ferrous sulfate solution, designated: magnetic palm kernel shell from iron suspension (MPKSF). Batch experiments were conducted using two methods: (1) one-factor-at-a-time and (2) Box-Behnken statistical analysis. Results showed that the optimum conditions resulted in 95% of As(III) removal in the wastewater sample. The adsorption data were best fitted to the Langmuir isotherm. The adsorption of As(III) onto the MPKSF was confirmed by energy dispersive X-ray spectrometry analysis which detected the presence of As(III) of 0.52% on the surface of the MPKSF. The Fourier transform infrared spectroscopy analysis of the MPKSF-As presented a peak at 573 cm-1, which was assigned to M-O (metal-oxygen) bending, indicating the coordination of As(III) with oxygen through the formation of inner-sphere complexation, thereby indicating a covalent bonding between the MPKSF functional groups and As(III). The findings suggested that the MPKSF exhibited a strong capacity to efficiently remove As(III) from wastewater, while the desorption studies showed that the As(III) was rigidly bound to the MPKSF thereby eliminating the possibility of secondary pollution.

  9. Current-Driven Hydrogen Desorption from Graphene: Experiment and Theory

    Energy Technology Data Exchange (ETDEWEB)

    Gao, L.; Pal, Partha P.; Seideman, Tamar; Guisinger, Nathan P.; Guest, Jeffrey R.

    2016-02-04

    Electron-stimulated desorption of hydrogen from the graphene/SiC(0001) surface at room temperature was investigated with ultrahigh vacuum scanning tunneling microscopy and ab initio calculations in order to elucidate the desorption mechanisms and pathways. Two different desorption processes were observed. In the high electron energy regime (4-8 eV), the desorption yield is independent of both voltage and current, which is attributed to the direct electronic excitation of the C-H bond. In the low electron energy regime (2-4 eV), however, the desorption yield exhibits a threshold dependence on voltage, which is explained by the vibrational excitation of the C-H bond via transient ionization induced by inelastic tunneling electrons. The observed current-independence of the desorption yield suggests that the vibrational excitation is a singleelectron process. We also observed that the curvature of graphene dramatically affects hydrogen desorption. Desorption from concave regions was measured to be much more probable than desorption from convex regions in the low electron energy regime (~ 2 eV), as would be expected from the identified desorption mechanism

  10. I-129 Desorption from SRS Water Treatment Media from the Effluent Treatment Facility and the F-Area Groundwater Treatment Facility

    Energy Technology Data Exchange (ETDEWEB)

    Kaplan, D.I.

    2001-01-26

    The objective of this study was to quantify I-129 desorption of four waste materials and to provide reasonably conservative Kd values for modeling efforts. Since the ILV PA considers dose thousands of years in the future, additional attention was directed at evaluating how I-129 desorption changed as a function of time. The scope of this work involved evaluating four waste materials (F-WTU Dowex 21K, F-WTU Sludge, ETF Carbon, and ETF GT-73) under two aqueous conditions (acid rain and cement simulants) by two different experimental protocols (static batch and dynamic flow column experiments).

  11. Water sorption characteristics of a new type of gelatine powder, produced by a new high-pressure micronisation process.

    Science.gov (United States)

    Reibe, Christian; Knez, Zeljko

    2010-06-01

    A new high-pressure micronisation process for Gelatine has been developed. By applying this process to gelatine, a new type of Gelatine was produced: Dry and pure Gelatine powder of high molecular mass. This powder was investigated, regarding its sorption behaviour and compared to its feedstock material. The feedstock Gelatine was of type B 200 Bloom, 6 mesh, having a molecular mass of 150,000 g mol-1. The produced Gelatine powder's molecular mass was around 130,000 g mol-1, while its mean particle size was 300 µm. Their sorption isotherms were investigated at 30 °C, 40 °C and 60 °C and water activities in the range from 0.055 to 0.836. At given water activities the Equilibrium Moisture Contents (EMC) decreases with increasing temperature. The measured sorption isotherms were fit with the Brunauer- Emmet- Teller (BET)- model and the Guggenheim- Anderson- deBoer (GAB)- model. Both models described the adsorption behaviour well in their range of validity, while only the GAB-model was adequate for describing the desorption behaviour. Hysteresis effect occurred in each adsorption-desorption pair. The isosteric heat of sorption of both substances was determined for adsorption, desorption respectively. Slight differences in the sorption behaviour occurred due to processing, while quality of the gelatine was not affected.

  12. Desorption of 137Cs+ from mosses

    Directory of Open Access Journals (Sweden)

    OLGICA NEDIC

    2002-09-01

    Full Text Available Mosses are biomonitors that accumulate large amounts of various pollutants, including radionuclides. In this work we investigated the possibility of 137Cs extraction from mosses, as well as the significance of species specificity on the efficiency of 137Cs desorption. Salt and acid solutions were used as extraction media. It was shown that a 5 % solution of both ammonium oxalate and phosphoric acid was able to desorb 81.8 % of 137Cs+ from Homalothecium sericeum, which was 39.9 % more than desorption from water. At the same time, most of the desorbed 137Cs+ was incorporated in crystals that precipitated from the solution. An interspecies difference in respect to 137Cs+ desorption was noticed.

  13. An infrared measurement of chemical desorption from interstellar ice analogues

    Science.gov (United States)

    Oba, Y.; Tomaru, T.; Lamberts, T.; Kouchi, A.; Watanabe, N.

    2018-03-01

    In molecular clouds at temperatures as low as 10 K, all species except hydrogen and helium should be locked in the heterogeneous ice on dust grain surfaces. Nevertheless, astronomical observations have detected over 150 different species in the gas phase in these clouds. The mechanism by which molecules are released from the dust surface below thermal desorption temperatures to be detectable in the gas phase is crucial for understanding the chemical evolution in such cold clouds. Chemical desorption, caused by the excess energy of an exothermic reaction, was first proposed as a key molecular release mechanism almost 50 years ago1. Chemical desorption can, in principle, take place at any temperature, even below the thermal desorption temperature. Therefore, astrochemical network models commonly include this process2,3. Although there have been a few previous experimental efforts4-6, no infrared measurement of the surface (which has a strong advantage to quantify chemical desorption) has been performed. Here, we report the first infrared in situ measurement of chemical desorption during the reactions H + H2S → HS + H2 (reaction 1) and HS + H → H2S (reaction 2), which are key to interstellar sulphur chemistry2,3. The present study clearly demonstrates that chemical desorption is a more efficient process for releasing H2S into the gas phase than was previously believed. The obtained effective cross-section for chemical desorption indicates that the chemical desorption rate exceeds the photodesorption rate in typical interstellar environments.

  14. Corrigendum to “Sorption/desorption of non-hydrophobic and ionisable pharmaceutical and personal care products from reclaimed water onto/from a natural sediment” Sci Total Environ 472 (2014) 273–281

    Energy Technology Data Exchange (ETDEWEB)

    Martínez-Hernández, Virtudes, E-mail: virtudes.martinez@imdea.org [IMDEA Agua, Madrid Institute for Advanced Studies in Water, Parque Científico Tecnológico de la Universidad de Alcalá, 28805 Alcalá de Henares, Madrid (Spain); Meffe, Raffaella; Herrera, Sonia [IMDEA Agua, Madrid Institute for Advanced Studies in Water, Parque Científico Tecnológico de la Universidad de Alcalá, 28805 Alcalá de Henares, Madrid (Spain); Arranz, Elena [University of Alcalá, Geography and Geology Department, 28871 Alcalá de Henares, Madrid (Spain); Bustamante, Irene de [IMDEA Agua, Madrid Institute for Advanced Studies in Water, Parque Científico Tecnológico de la Universidad de Alcalá, 28805 Alcalá de Henares, Madrid (Spain); University of Alcalá, Geography and Geology Department, 28871 Alcalá de Henares, Madrid (Spain)

    2015-02-01

    In the present work, the sorption of pharmaceutical and personal care products (PPCPs) (acetaminophen, atenolol, carbamazepine, caffeine, naproxen and sulphamethoxazole) onto the natural organic matter (NOM) and the inorganic surfaces of a natural sandy loam sediment was quantified separately. The quantification was based on the PPCP charge, their degree of ionisation, their octanol-water partitioning coefficient (K{sub OW}) and the sediment organic carbon fraction (ƒ{sub OC}). PPCP desorption from the sediment was examined under conditions of infiltrating water containing a high concentration of inorganic ions (mimicking infiltrating reclaimed water), and a low concentration (and smaller diversity) of inorganic ions (mimicking rainwater infiltration). Batch tests were performed using a sediment/water ratio of 1:4 and a PPCP initial concentration ranging from 1 to 100 μg L{sup −1}. The results showed the type and degree of PPCP ionisation to strongly influence the sorption of these compounds onto the sediment. The sorption of cationic species onto the sediment was higher than that of anionic species and mostly reversible; the sorption of neutral species was negligible with the exception of caffeine. The anionic species sorbed less onto the sediment, but also desorbed less easily. Most of the compounds showed a sorption that was highly influenced by interaction with mineral surfaces. The presence of inorganic ions had no impact on the desorption of the PPCPs from the sediment. According to the calculated percentages of removal, the mobility followed the order: carbamazepine > acetaminophen > naproxen > atenolol > sulphamethoxazole > caffeine.

  15. Qualification of the ALKASORB sorbent for the sorption-enhanced water-gas shift process

    Energy Technology Data Exchange (ETDEWEB)

    Van Selow, E.R.; Cobden, P.D.; Dijk, Van H.A.J.; Walspurger, S.; Verbraeken, P.A.; Jansen, D.

    2013-07-01

    For the sorption-enhanced water-gas shift (SEWGS) process, a new sorbent material has been qualified in a reactor of 2 m length under conditions close to industrial designs. The sorbent ALKASORB is a potassium-carbonate promoted hydrotalcite-based compound. ALKASORB is shown to have many favourable properties in comparison to the reference sorbent, in particular with respect to mechanical stability. The cyclic capacity of the new compound is substantially higher than the cyclic capacity of the reference sorbent, and it allows a reduction of the steam requirement of 50%. The sorbent has demonstrated catalytic activity for the water-gas shift reaction that is sufficient to omit a separate catalyst. It is demonstrated that the sorbent remains chemically and mechanically stable during operation of at least 2000 adsorption-desorption cycles, even in the presence of H2S in the feed. H2S is shown not to influence CO2 adsorption capacity and is co-captured with the CO2. In contrast to the reference material that showed mechanical degradation during extended adsorption-desorption cycles, the new material is stable and allows to obtain carbon capture levels exceeding 95% more efficiently and more economically since the required size of the vessels will be smaller.

  16. Perdeuterated n-alkanes for improved data processing in thermal desorption gas chromatography/mass spectrometry I. Retention indices for identification.

    Science.gov (United States)

    Massold, Emilie

    2007-06-22

    The identification of organic compounds by GC/MS is useful in various areas such as fuel, indoor and outdoor air and flavour and fragrance applications. Multi-compound mixtures often contain isomeric compounds which have similar mass spectra and sometimes cannot be unambiguously identified by library search alone. Retention indices can help with confirmation of identification if they are reproducible. Using perdeuterated n-alkanes as a reference series for calculation of retention indices in GC/MS has a clear benefit because of the distinctive ion trace of m/z 34. Thermal desorption is useful for analysis of volatile organic compounds (VOCs) in air after sampling on appropriate sorbent cartridges. Comparison of indices between three systems, consisting of a thermal desorption unit, a gas chromatograph and a mass spectrometer, showed good agreement for compounds with well-defined peaks, whereas retention times varied.

  17. Anaerobic digestion trials with HTC process water

    OpenAIRE

    Nilsson, Erik

    2017-01-01

    Hydrothermal carbonization (HTC) is a process where elevated temperature and pressure is used in order to convert biomass to hydrochar, a coal-like substance with good dewatering properties and many potential uses. HTC can be used to treat digestate from anaerobic digestion, but the process water that remains after the hydrochar has been recovered needs to be treated further in the wastewater treatment plant. In order to make HTC more competitive compared to other sludge treatments it is impo...

  18. Photocatalysis: Oxidative Processes in Water Treatment

    Directory of Open Access Journals (Sweden)

    Roman V. Prihod'ko

    2013-01-01

    Full Text Available The efficiency of various homogeneous and heterogeneous systems photocatalytic processes destructive oxidation of organic compounds of different classes is considered. It is shown that photocatalytic methods can significantly increase the speed and depth (up to complete mineralization of decomposition processes of toxicants. The use of photocatalysis (PC in the creation of low-power water treatment technologies is a promising direction in addressing environmental problems of the hydrosphere.

  19. Quantification of water usage at a South African platinum processing ...

    African Journals Online (AJOL)

    Hoekstra et al (2011) define blue-, green- and grey-water foot- prints for a process as follows: Blue water. The blue-water footprint of a process is the volume of ground and surface water that is consumed in the process. Consumption is defined as water that is not returned to the same water resource, or is not returned during ...

  20. Ionic Adsorption and Desorption of CNT Nanoropes

    Directory of Open Access Journals (Sweden)

    Jun-Jun Shang

    2016-09-01

    Full Text Available A nanorope is comprised of several carbon nanotubes (CNTs with different chiralities. A molecular dynamic model is built to investigate the ionic adsorption and desorption of the CNT nanoropes. The charge distribution on the nanorope is obtained by using a modified gradient method based on classical electrostatic theory. The electrostatic interactions among charged carbon atoms are calculated by using the Coulomb law. It was found here that the charged nanorope can adsorb heavy metal ions, and the adsorption and desorption can be realized by controlling the strength of applied electric field. The distance between the ions and the nanorope as well as the amount of ions have an effect on the adsorption capacity of the nanorope. The desorption process takes less time than that of adsorption. The study indicates that the CNT nanorope can be used as a core element of devices for sewage treatment.

  1. Product desorption limitations in selective photocatalytic oxidation

    NARCIS (Netherlands)

    Renckens, T.J.A.; Almeida, A.R.; Almeida, A.R.; Damen, M.R.; Kreutzer, M.T.; Mul, Guido

    2010-01-01

    The rate of photocatalytic processes can be significantly improved if strongly bound products rapidly desorb to free up active sites. This paper deals with the rate of desorption of cyclohexanone, the product of the liquid-phase photo-oxidation of cyclohexane. Dynamic step-response and

  2. Competitive adsorption/desorption of tetracycline, oxytetracycline and chlortetracycline on two acid soils: Stirred flow chamber experiments.

    Science.gov (United States)

    Fernández-Calviño, David; Bermúdez-Couso, Alipio; Arias-Estévez, Manuel; Nóvoa-Muñoz, Juan Carlos; Fernández-Sanjurjo, Maria J; Álvarez-Rodríguez, Esperanza; Núñez-Delgado, Avelino

    2015-09-01

    The objective of this work was to study the competitive adsorption/desorption of tetracycline (TC), oxytetracycline (OTC) and chlortetracycline (CTC) on two acid soils. We used the stirred flow chamber technique to obtain experimental data on rapid kinetic processes affecting the retention/release of the antibiotics. Both adsorption and desorption were higher on soil 1 (which showed the highest carbon, clay and Al and Fe oxides content) than on soil 2. Moreover, hysteresis affected the adsorption/desorption processes. Experimental data were fitted to a pseudo-first order equation, resulting qamax (adsorption maximum) values that were higher for soil 1 than for soil 2, and indicating that CTC competed with TC more intensely than OTC in soil 1. Regarding soil 2, the values corresponding to the adsorption kinetics constants (ka) and desorption kinetics constants for fast sites (kd1), followed a trend inverse to qamax and qdmax respectively. In conclusion, competition affected adsorption/desorption kinetics for the three antibiotics assayed, and thus retention/release and subsequent transport processes in soil and water environments. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Aqueous Processing of Atmospheric Organic Particles in Cloud Water Collected via Aircraft Sampling

    Energy Technology Data Exchange (ETDEWEB)

    Boone, Eric J.; Laskin, Alexander; Laskin, Julia; Wirth, Christopher; Shepson, Paul B.; Stirm, Brian H.; Pratt, Kerri A.

    2015-07-21

    Cloud water and below-cloud atmospheric particle samples were collected onboard a research aircraft during the Southern Oxidant and Aerosol Study (SOAS) over a forested region of Alabama in June 2013. The organic molecular composition of the samples was studied to gain insights into the aqueous-phase processing of organic compounds within cloud droplets. High resolution mass spectrometry with nanospray desorption electrospray ionization and direct infusion electrospray ionization were utilized to compare the organic composition of the particle and cloud water samples, respectively. Isoprene and monoterpene-derived organosulfates and oligomers were identified in both the particles and cloud water, showing the significant influence of biogenic volatile organic compound oxidation above the forested region. While the average O:C ratios of the organic compounds were similar between the atmospheric particle and cloud water samples, the chemical composition of these samples was quite different. Specifically, hydrolysis of organosulfates and formation of nitrogen-containing compounds were observed for the cloud water when compared to the atmospheric particle samples, demonstrating that cloud processing changes the composition of organic aerosol.

  4. Kinetic Ising model for desorption from a chain

    Science.gov (United States)

    Geldart, D. J. W.; Kreuzer, H. J.; Rys, Franz S.

    1986-10-01

    Adsorption along a linear chain of adsorption sites is considered in an Ising model with nearest neighbor interactions. The kinetics are studied in a master equation approach with transition probabilities describing single spin flips to mimic adsorption-desorption processes. Exchange of two spins to account for diffusion can be included as well. Numerical results show that desorption is frequently of fractional (including zero) order. Only at low coverage and high temperature is desorption a first order process. Finite size effects and readsorption are also studied.

  5. Sensory processing of water currents by fishes.

    Science.gov (United States)

    Montgomery, J; Carton, G; Voigt, R; Baker, C; Diebel, C

    2000-01-01

    Water currents are extremely important in the aquatic environment and play a very significant role in the lives of fishes. Sensory processing of water currents involves a number of sensory modalities including the inner ear, vision, tactile sense and the mechanosensory lateral line. The inner ear will detect whole-body accelerations generated by changes in flow, or by turbulence, whereas visual and tactile inputs will signal translational movement with respect to an external visual or tactile reference frame. The superficial neuromasts of the mechanosensory lateral line detect flow over the surface of the body and have the appropriate anatomical distribution and physiological properties to signal the strength and the direction of flow and, hence, contribute to the detection of regional differences in flow over different parts of the body. PMID:11079424

  6. [Desorption characteristics of phosphorus in tea tree rhizosphere soil].

    Science.gov (United States)

    Yang, Wei; Zhou, Wei-Jun; Bao, Chun-Hong; Miao, Xiao-Lin; Hu, Wen-Min

    2013-07-01

    In order to explore the phosphorus (P) release process and its supply mechanism in tea tree rhizosphere soil, an exogenous P adsorption and culture experiment was conducted to study the P desorption process and characters in the tea tree rhizosphere soils having been cultivated for different years and derived from different parent materials. The least squares method was used to fit the isotherms of P desorption kinetics. There was an obvious difference in the P desorption process between the rhizosphere soils and non-rhizosphere soils. The P desorption ability of the rhizosphere soils was significantly higher than that of the non-rhizosphere soils. As compared with non-rhizosphere soils, rhizosphere soils had higher available P content, P desorption rate, and beta value (desorbed P of per unit adsorbed P), with the average increment being 5.49 mg x kg(-1), 1.7%, and 24.4%, respectively. The P desorption ability of the rhizosphere soils derived from different parent materials was in the order of granite > quaternary red clay > slate. The average available P content and P desorption ability of the rhizosphere soils increased with increasing cultivation years.

  7. Thermophilic aerobic post treatment of anaerobically pretreated paper process water

    NARCIS (Netherlands)

    Vogelaar, J.C.T.

    2002-01-01

    Thermophilic waste- or process water treatment increases in importance as industries shift from end-of-pipe treatment towards integrated process water treatment. The need for process water treatment becomes evident as the levels of pollutants in industrial water

  8. Adsorption and desorption behavior of zinc oxide nanoparticles at the soil-water interface using standardized soil LUFA 2.2 and 2.3

    DEFF Research Database (Denmark)

    Skjolding, Lars Michael; Winther-Nielsen, Margrethe; Baun, Anders

    for adsorption and desorption was used to evaluate the behavior of ZnO NP in two different standardized soils. The standardized soils tested were LUFA 2.2 and 2.3. The applied concentration was 3.35 mg Zn/L and samples were taken at 2, 4, 6 and 24 hours. The ZnO NP had a primary particle size of 35 nm...... and was characterized by ICP-MS, DLS, BET and TEM. During the test a very rapid adsorption of the ZnO NP was observed on both soils reaching equilibrium within the first two hours of the test. The equilibrium concentration was found to be 2.02±0.2 mg Zn/L and 0.29±0.10 mg Zn/L for LUFA 2.2 and LUFA 2.3 respectively...

  9. Defluoridation of drinking water using adsorption processes.

    Science.gov (United States)

    Loganathan, Paripurnanda; Vigneswaran, Saravanamuthu; Kandasamy, Jaya; Naidu, Ravi

    2013-03-15

    Excessive intake of fluoride (F), mainly through drinking water, is a serious health hazard affecting humans worldwide. There are several methods used for the defluoridation of drinking water, of which adsorption processes are generally considered attractive because of their effectiveness, convenience, ease of operation, simplicity of design, and for economic and environmental reasons. In this paper, we present a comprehensive and a critical literature review on various adsorbents used for defluoridation, their relative effectiveness, mechanisms and thermodynamics of adsorption, and suggestions are made on choice of adsorbents for various circumstances. Effects of pH, temperature, kinetics and co-existing anions on F adsorption are also reviewed. Because the adsorption is very weak in extremely low or high pHs, depending on the adsorbent, acids or alkalis are used to desorb F and regenerate the adsorbents. However, adsorption capacity generally decreases with repeated use of the regenerated adsorbent. Future research needs to explore highly efficient, low cost adsorbents that can be easily regenerated for reuse over several cycles of operations without significant loss of adsorptive capacity and which have good hydraulic conductivity to prevent filter clogging during the fixed-bed treatment process. Copyright © 2013 Elsevier B.V. All rights reserved.

  10. A Transformational Journey: Compositional Changes in Organic Matter during Desorption from Sediments

    Science.gov (United States)

    Matiasek, S. J.; Pellerin, B. A.; Spencer, R.; Bergamaschi, B. A.; Hernes, P.

    2016-12-01

    The release of organic matter (OM) from suspended particles via desorption is a critical component of OM cycling since dissolved OM (DOM) fuels aquatic ecosystems and is a precursor for disinfection by-products formation. This study assessed the elemental and molecular composition of DOM desorbed abiotically from sediments and soils of an irrigated agricultural watershed of northern California. Relative to mineral-bound OM, the released DOM was nitrogen-poor (lower carbon:nitrogen ratios) and depleted in amino acids and lignin phenols (lower carbon-normalized yields). Water-extracted DOM appeared substantially more degraded than its parent particulate OM with increased molar contributions of acidic amino acids, non-protein amino acids, and acidic lignin phenols, all molecular indicators of a more extensively processed OM pool. Desorption processes also significantly altered lignin compositional ratios which help distinguish vascular-plant sources of DOM. Specific optical parameters, including spectral slope, specific UV absorbance at 254 nm (SUVA254), and fluorescence index (FI), did not constitute useful proxies for the desorbed DOM pool, while absorption coefficients and fluorescence peak intensities were strongly correlated with extracted DOM concentrations and composition. This study highlights the profound impact of desorption on DOM composition which, if unaccounted for, could lead to misinterpretations of common biomarkers and optical proxies used to predict DOM sources and reactivity. Our findings suggest that sediments contribute a biogeochemically distinct source of DOM to surface waters, with potential impacts on aquatic health and drinking water quality.

  11. Rapid prediction of long-term rates of contaminant desorption from soils and sediments.

    Science.gov (United States)

    Johnson, M D; Weber, W J

    2001-01-15

    A method using heated and superheated (subcritical) water is described for rapid prediction of long-term desorption rates from contaminated geosorbents. Rates of contaminant release are measured at temperatures between 75 and 150 degrees C using a dynamic water desorption technique. The subcritical desorption rate data are then modeled to calculate apparent activation energies, and these activation energies are used to predict desorption behaviors at any desired ambient temperature. Predictions of long-term release rates based on this methodology were found to correlate well with experimental 25 degrees C desorption data measured over periods of up to 640 days, even though the 25 degrees C desorption rates were observed to vary by up to 2 orders of magnitude for different geosorbent types and initial solid phase contaminant loading levels. Desorption profiles measured under elevated temperature and pressure conditions closely matched those at 25 degrees C and ambient pressure, but the time scales associated with the high-temperature measurements were up to 3 orders of magnitude lower. The subcritical water technique rapidly estimates rates of desorption-resistant contaminant release as well as those for more labile substances. The practical implications of the methodology are significant because desorption observed under field conditions and ambient temperatures typically proceeds over periods of months or years, while the high temperature experiments used for prediction of such field desorption phenomena can be completed within periods of only hours or days.

  12. Defluoridation of drinking water using adsorption processes

    Energy Technology Data Exchange (ETDEWEB)

    Loganathan, Paripurnanda [Faculty of Engineering and Information Technology, University of Technology, Sydney, NSW, 2007 (Australia); Vigneswaran, Saravanamuthu, E-mail: s.vigneswaran@uts.edu.au [Faculty of Engineering and Information Technology, University of Technology, Sydney, NSW, 2007 (Australia); Kandasamy, Jaya [Faculty of Engineering and Information Technology, University of Technology, Sydney, NSW, 2007 (Australia); Naidu, Ravi [Centre for Cooperative Research for Contamination Assessment and Remediation of the Environment (CRC CARE), University of South Australia, Adelaide, SA 5095 (Australia)

    2013-03-15

    Highlights: ► Comprehensive and critical literature review on various adsorbents used for defluoridation. ► pH, temperature, kinetics and co-existing anions effects on F adsorption. ► Choice of adsorbents for various circumstances. ► Adsorption thermodynamics and mechanisms. ► Future research on efficient, low cost adsorbents which are easily regenerated. -- Abstract: Excessive intake of fluoride (F), mainly through drinking water, is a serious health hazard affecting humans worldwide. There are several methods used for the defluoridation of drinking water, of which adsorption processes are generally considered attractive because of their effectiveness, convenience, ease of operation, simplicity of design, and for economic and environmental reasons. In this paper, we present a comprehensive and a critical literature review on various adsorbents used for defluoridation, their relative effectiveness, mechanisms and thermodynamics of adsorption, and suggestions are made on choice of adsorbents for various circumstances. Effects of pH, temperature, kinetics and co-existing anions on F adsorption are also reviewed. Because the adsorption is very weak in extremely low or high pHs, depending on the adsorbent, acids or alkalis are used to desorb F and regenerate the adsorbents. However, adsorption capacity generally decreases with repeated use of the regenerated adsorbent. Future research needs to explore highly efficient, low cost adsorbents that can be easily regenerated for reuse over several cycles of operations without significant loss of adsorptive capacity and which have good hydraulic conductivity to prevent filter clogging during the fixed-bed treatment process.

  13. Optimization of Drinking Water Treatment Processes Using Artificial ...

    African Journals Online (AJOL)

    Drinking water treatment is the process of removing microorganisms and solid from water through different methods such as coagulation and filtration. Artificial neural network (ANN) was developed for process and cost optimization of drinking water treatment processes. Results obtained from ANN model showed that ANN ...

  14. Moisture adsorption and desorption behavior of sludge powder.

    Science.gov (United States)

    Freire, F B; Bentes Freire, F; Pires, E C; Freire, J T

    2007-11-01

    In this work, the moisture adsorption and desorption isotherms were determined with the aim of defining the range of moisture content for storage of sludge powder. Equilibrium moisture content provides the basis for information not only on how much water has been taken out of a system but also on how fast drying is taking place (drying rate). Once the drying process is accomplished, the main concern rests on the storage of the dried final product. Still, the equilibrium moisture content is valuable information in that it has a major effect on the product physical and chemical properties. The present work also addresses the problem of selecting the best fit for equilibrium moisture content of sludge powder out of six well-known correlations for moisture sorption isotherms of solids: Henderson, Henderson-Thompson, Chung-Pfost, Chen-Clayton, Modified Halsey and Oswin. The equilibrium moisture content was determined by the static method (saturated salt solutions), in which the atmosphere surrounding the product is in equilibrium with the product without mechanical movement of the air or the product. Experiments were carried out under isothermal conditions at 20 and 40 degrees C. By calculating the regression coefficient, the residuals and the bias measure of Box for the equilibrium moisture content, the study showed that the Oswin Model was the most suitable. The range enclosed within the adsorption isotherm at 40 degrees C and the desorption isotherm at 20 degrees C defines the moisture extremes for storage in most tropical areas of the world.

  15. Hydrocarbon analysis using desorption atmospheric pressure chemical ionization

    KAUST Repository

    Jjunju, Fred Paul Mark

    2013-07-01

    Characterization of the various petroleum constituents (hydronaphthalenes, thiophenes, alkyl substituted benzenes, pyridines, fluorenes, and polycyclic aromatic hydrocarbons) was achieved under ambient conditions without sample preparation by desorption atmospheric pressure chemical ionization (DAPCI). Conditions were chosen for the DAPCI experiments to control whether ionization was by proton or electron transfer. The protonated molecule [M+H]+ and the hydride abstracted [MH]+ form were observed when using an inert gas, typically nitrogen, to direct a lightly ionized plasma generated by corona discharge onto the sample surface in air. The abundant water cluster ions generated in this experiment react with condensed-phase functionalized hydrocarbon model compounds and their mixtures at or near the sample surface. On the other hand, when naphthalene was doped into the DAPCI gas stream, its radical cation served as a charge exchange reagent, yielding molecular radical cations (M+) of the hydrocarbons. This mode of sample ionization provided mass spectra with better signal/noise ratios and without unwanted side-products. It also extended the applicability of DAPCI to petroleum constituents which could not be analyzed through proton transfer (e.g., higher molecular PAHs such as chrysene). The thermochemistry governing the individual ionization processes is discussed and a desorption/ionization mechanism is inferred. © 2012 Elsevier B.V.

  16. Effect of the method of process on the control of microbial growth by water activity in foods

    Science.gov (United States)

    Labuzu, T. D.

    1972-01-01

    Two methods for preparation of intermediate moisture foods (IMF) were investigated; water absorption and water desorption technique. Results indicate that shelf stability of IMF systems might be enhanced by preparing foods by rehumidifying dehydrated foods to optimum water activity rather than drying food to reduce the water activity.

  17. Effect of humic acid on the adsorption/desorption behavior of glyphosate on goethite. Isotherms and kinetics.

    Science.gov (United States)

    Arroyave, Jeison Manuel; Waiman, Carolina C; Zanini, Graciela P; Avena, Marcelo J

    2016-02-01

    The effects of humic acid (HA) on the adsorption/desorption of glyphosate (Gly) on goethite were investigated under pseudo equilibrium conditions by adsorption isotherms and under kinetic conditions by ATR-FTIR spectroscopy. Isotherms reveal that the attachment of Gly is almost completely inhibited by HA molecules. The opposite effect is not observed: HA adsorption is not affected by the presence of Gly. ATR-FTIR allowed the simultaneous detection of adsorbed HA and Gly during kinetic runs, revealing that HA at the surface decreases markedly the adsorption rate of Gly likely as a result of a decreased availability of sites for Gly adsorption and because of electrostatic repulsion. In addition, HA in solution increases the desorption rate of Gly. The rate law for Gly desorption could be determined giving important insights on the desorption mechanism. The herbicide is desorbed by two parallel processes: i) a direct detachment from the surface, which is first order in adsorbed Gly; and ii) a ligand exchange with HA molecules, which is first order in adsorbed Gly and first order in dissolved HA. Rate constants for both processes were quantified, leading to half-lives of 3.7 h for the first process, and 1.4 h for the second process in a 400 mg L(-1) HA solution. These data are important for modeling the dynamics of glyphosate in environmentally relevant systems, such as soils and surface waters. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. Nonideal transport of reactive contaminants in heterogeneous porous media: 7. distributed-domain model incorporating immiscible-liquid dissolution and rate-limited sorption/desorption.

    Science.gov (United States)

    Zhang, Zhihui; Brusseau, Mark L

    2004-10-01

    The purpose of this work is to present a distributed-domain mathematical model incorporating the primary mass-transfer processes that mediate the transport of immiscible organic liquid constituents in water-saturated, locally heterogeneous porous media. Specifically, the impact of grain/pore-scale heterogeneity on immiscible-liquid dissolution and sorption/desorption is represented in the model by describing the system as comprising a continuous distribution of mass-transfer domains. With this conceptualization, the distributions of the initial dissolution rate coefficient and the sorption/desorption rate coefficient are represented as probability density functions. Several sets of numerical experiments are conducted to examine the effects of heterogeneous dissolution and sorption/desorption on contaminant transport and elution. Four scenarios with different combinations of uniform/heterogeneous rate-limited dissolution and uniform/heterogeneous rate-limited sorption/desorption are evaluated. The results show that both heterogeneous rate-limited sorption/desorption and heterogeneous rate-limited dissolution can significantly increase the time or pore volumes required to elute immiscible-liquid constituents from a contaminated porous medium. However, sorption/desorption has minimal influence on elution behavior until essentially all of the immiscible liquid has been removed. For typical immiscible-liquid constituents that have relatively low sorption, the asymptotic elution tailing produced by heterogeneous rate-limited sorption/desorption begins at effluent concentrations that are several orders of magnitude below the initial steady-state concentrations associated with dissolution of the immiscible liquid. Conversely, the enhanced elution tailing associated with heterogeneous rate-limited dissolution begins at concentrations that are approximately one-tenth of the initial steady-state concentrations. Hence, dissolution may generally control elution behavior of

  19. Waste water reuse pathways for processing tomato

    DEFF Research Database (Denmark)

    Battilani, A; Plauborg, Finn; Andersen, Mathias Neumann

    a safe use of waste water produced by small communities/industries (≤2000 EI) or of treated water discharged in irrigation channels. Water treatment technologies are coupled with irrigation strategies and technologies to obtain a flexible, easy to use, integrated management.......  Direct or indirect water reuse involves several aspects: contamination by faecal, inorganic and xenobiotic pollutants; high levels of suspended solids and salinity; rational use of the dissolved nutrients (particularly nitrogen). The challenge is apply new strategies and technologies which allows...... to use the lowest irrigation water quality without harming nor food safety neither yield and fruit or derivatives quality. The EU project SAFIR aims help farmers solve problems with low quality water and decreased access to water. New water treatment devices (prototypes) are under development to allow...

  20. Stir-bar-sorptive extraction and liquid desorption combined with large-volume injection gas chromatography-mass spectrometry for ultra-trace analysis of musk compounds in environmental water matrices.

    Science.gov (United States)

    Silva, Ana Rita M; Nogueira, J M F

    2010-03-01

    Stir-bar-sorptive extraction with liquid desorption followed by large-volume injection and capillary gas chromatography coupled to mass spectrometry in selected ion monitoring acquisition mode (SBSE-LD/LVI-GC-MS(SIM)) has been developed to monitor ultra-traces of four musks (celestolide (ADBI), galaxolide (HHCB), tonalide (AHTN) and musk ketone (MK)) in environmental water matrices. Instrumental calibration (LVI-GC-MS(SIM)) and experimental conditions that could affect the SBSE-LD efficiency are discussed. Assays performed on 30-mL water samples spiked at 200 ng L(-1) under optimized experimental conditions yielded recoveries ranging from 83.7 ± 8.1% (MK) to 107.6 ± 10.8% (HHCB). Furthermore, the experimental data were in very good agreement with predicted theoretical equilibria described by octanol-water partition coefficients (K (PDMS/W) ≈ K (O/W)). The methodology also showed excellent linear dynamic ranges for the four musks studied, with correlation coefficients higher than 0.9961, limits of detection and quantification between 12 and 19 ng L(-1) and between 41 and 62 ng L(-1), respectively, and suitable precision (ultra-trace level, overcoming several disadvantages presented by other sample-preparation techniques.

  1. Drying by desorption: a method to determine and optimize the spray drying parameters of food and dairy products regarding to the water availability

    OpenAIRE

    Schuck, Pierre; Dolivet, Anne; Mejean, Serge; Jeantet, Romain

    2016-01-01

    The main aim of this study was to develop a method to simulate the transfer conditions (energy and water) of spray-drying. Typical curves were registered with the water activity meter on water, dairy and food concentrates (Fig 1.) [1]. These curves showed that the relative humidity (RH) from the pressure sensor as a function of time can be represented by a sigmoid equation. Two phases can be identified on the curves obtained for pure water and milk concentrates: Initially, at the beginning of...

  2. Identification of water-soluble heavy crude oil organic-acids, bases, and neutrals by electrospray ionization and field desorption ionization fourier transform ion cyclotron resonance mass spectrometry.

    Science.gov (United States)

    Stanford, Lateefah A; Kim, Sunghwan; Klein, Geoffrey C; Smith, Donald F; Rodgers, Ryan P; Marshall, Alan G

    2007-04-15

    We identify water-soluble (23 degrees C) crude oil NSO nonvolatile acidic, basic, and neutral crude oil hydrocarbons by negative-ion ESI and continuous flow FD FT-ICR MS at an average mass resolving power, m/deltam50% = 550,000. Of the 7000+ singly charged acidic species identified in South American crude oil, surprisingly, many are water-soluble, and much more so in pure water than in seawater. The truncated m/z distributions for water-soluble components exhibit preferential molecular weight, size, and heteroatom class influences on hydrocarbon solubility. Acidic water-soluble heteroatomic classes detected at >1% relative abundance include O, O2, O3, O4, OS, O2S, O3S, O4S, NO2, NO3, and NO4. Parent oil class abundance does not directly relate to abundance in the water-soluble fraction. Acidic oxygen-containing classes are most prevalent in the water-solubles, whereas acidic nitrogen-containing species are least soluble. In contrast to acidic nitrogen-containing heteroatomic classes, basic nitrogen classes are water-soluble. Water-soluble heteroatomic basic classes detected at >1% relative abundance include N, NO, NO2, NS, NS2, NOS, NO2S, N2, N2O, N2O2, OS, O2S, and O2S2.

  3. 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

  4. Quantification of water usage at a South African platinum processing ...

    African Journals Online (AJOL)

    The direct water footprint for 2 concentrators, a smelter and a tailings dam of a platinum processing plant were calculated using the Water Footprint Network assessment method. This includes the sum of the blue-, green- and grey-water footprints. Water footprints of chemicals used during flotation were excluded from the ...

  5. Modeling Benthic Sediment Processes to Predict Water ...

    Science.gov (United States)

    The benthic sediment acts as a huge reservoir of particulate and dissolved material (within interstitial water) which can contribute to loading of contaminants and nutrients to the water column. A benthic sediment model is presented in this report to predict spatial and temporal benthic fluxes of nutrients and chemicals in Narragansett Bay. A benthic sediment model is presented in this report to identify benthic flux into the water column in Narragansett Bay. Benthic flux is essential to properly model water quality and ecology in estuarine and coastal systems.

  6. Examination of the skin barrier repair/wound healing process using a living skin equivalent (LSE) model and matrix-assisted laser desorption-ionization-mass spectrometry imaging (MALDI-MSI).

    Science.gov (United States)

    Lewis, E E L; Barrett, M R T; Freeman-Parry, L; Bojar, R A; Clench, M R

    2018-01-21

    Examination of the skin barrier repair/wound healing process using a living skin equivalent (LSE) model and matrix-assisted laser desorption/ionization-mass spectrometry imaging (MALDI-MSI) to identify lipids directly involved as potential biomarkers. These biomarkers may be used to determine whether an in vivo wound is going to heal for example if infected. An in vitro LSE model was wounded with a scalpel blade and assessed at day 4 post wounding by histology and MALDI-MSI. Samples were sectioned at wound site and were either formalin fixed paraffin embedded (FFPE) for histology or snapped frozen (FF) for MSI analysis. The combination of using an in vitro wounded skin model with MSI allowed the identification of lipids involved in the skin barrier repair/wound healing process. The technique was able to highlight lipids directly in the wound site and distinguish differences in lipid distribution between the epidermis and wound site. This novel method of coupling an in vitro LSE with MSI allowed in depth molecular analysis of the skin barrier repair/wound healing process. The technique allowed the identification of lipids directly involved in the skin barrier repair/wound healing process, indicating these biomarkers may be potentially be used within clinic. These biomarkers will help determine, which stage of the skin barrier repair/wound healing process the wound is in to provide the best treatment. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  7. Adsorption and desorption dynamics of citric acid anions in soil

    KAUST Repository

    Oburger, E.

    2011-07-26

    The functional role of organic acid anions in soil has been intensively investigated, with special focus on (i) microbial respiration and soil carbon dynamics, (ii) nutrient solubilization or (iii) metal detoxification and reduction of plant metal uptake. Little is known about the interaction dynamics of organic acid anions with the soil matrix and the potential impact of adsorption and desorption processes on the functional significance of these effects. The aim of this study was to characterize experimentally the adsorption and desorption dynamics of organic acid anions in five agricultural soils differing in iron and aluminium oxide contents and using citrate as a model carboxylate. Results showed that both adsorption and desorption processes were fast in all soils, reaching a steady state within approximately 1 hour. However, for a given total soil citrate concentration (ct) the steady state was critically dependent on the starting conditions of the experiment, whether most of the citrate was initially present in solution (cl) or held on the solid phase (cs). Specifically, desorption-led processes resulted in significantly smaller steady-state solution concentrations than adsorption-led processes, indicating that hysteresis occurred. As it is not possible to distinguish between different adsorption and desorption pools in soil experimentally, a new dynamic hysteresis model that relies only on measured soil solution concentrations was developed. The model satisfactorily explained experimental data and was able to predict dynamic adsorption and desorption behaviour. To demonstrate its use, we applied the model to two relevant situations involving exudation and microbial degradation. The study highlighted the complex nature of citrate adsorption and desorption dynamics in soil. We conclude that existing models need to incorporate both temporal and hysteresis components to describe realistically the role and fate of organic acids in soil processes. © 2011 The

  8. Determination of 1-chloro-4-[2,2,2-trichloro-1-(4-chlorophenyl)ethyl]benzene and related compounds in marine pore water by automated thermal desorption-gas chromatography/mass spectrometry using disposable optical fiber

    Science.gov (United States)

    Eganhouse, Robert P.; DiFilippo, Erica L

    2015-01-01

    A method is described for determination of ten DDT-related compounds in marine pore water based on equilibrium solid-phase microextraction (SPME) using commercial polydimethylsiloxane-coated optical fiber with analysis by automated thermal desorption-gas chromatography/mass spectrometry (TD-GC/MS). Thermally cleaned fiber was directly exposed to sediments and allowed to reach equilibrium under static conditions at the in situ field temperature. Following removal, fibers were rinsed, dried and cut into appropriate lengths for storage in leak-tight containers at -20°C. Analysis by TD-GC/MS under full scan (FS) and selected ion monitoring (SIM) modes was then performed. Pore-water method detection limits in FS and SIM modes were estimated at 0.05-2.4ng/L and 0.7-16pg/L, respectively. Precision of the method, including contributions from fiber handling, was less than 10%. Analysis of independently prepared solutions containing eight DDT compounds yielded concentrations that were within 6.9±5.5% and 0.1±14% of the actual concentrations in FS and SIM modes, respectively. The use of optical fiber with automated analysis allows for studies at high temporal and/or spatial resolution as well as for monitoring programs over large spatial and/or long temporal scales with adequate sample replication. This greatly enhances the flexibility of the technique and improves the ability to meet quality control objectives at significantly lower cost.

  9. Water Reuse in Industrial food Processing

    African Journals Online (AJOL)

    extremely diversified. It is therefore necessary to gather the various water types in categories, each of them are. defined by quality standards that'make them usable for several applications. An excessively high number of categories. (so high as to identify a water standard for every single use) is not generally useful, except in ...

  10. development of an automated batch-process solar water disinfection

    African Journals Online (AJOL)

    user

    (Joules) preset at the beginning of the experiment/disinfection process. Fig. 2: Schematic diagram of the automated batch- process solar water disinfection system. Fig. 3: Pictorial view of the automated batch-process solar water disinfection system. Figure 4: Circuitry of Arduino® microcontroller with the different sensors ...

  11. SAGD processes with fresh water contact

    Energy Technology Data Exchange (ETDEWEB)

    Thimm, H.F. [Thimm Petroleum Technologies Inc. (Canada)

    2011-07-01

    In the Athabasca region, several bitumen reservoirs are shallow, located less than 400 meters below grade. These deposits are suitable for SAGD exploitation but the steam could come into contact with fresh water, which carries the risk of contaminating this resource. Operators are thus required by regulators to address this issue at the project application stage. The aim of this paper is to examine the potential effect of contact between fresh water and a bitumen bearing zone in a field in Northern Alberta. Investigations were conducted with a steam zone temperature of 200 degree Celsius and measurements were conducted at a plant close to the proposed project. Results showed that the accumulation of hydrogen sulphide would protect the water column and PAH, benzene and toluene were found to be potential concerns but they were not detected during implementation of a similar project. This paper demonstrated that the proposed project does not constitute a threat to fresh water.

  12. 2 Water Sorption Isotherm.cdr

    African Journals Online (AJOL)

    Administrator

    desorption) as the initial water content of 58% was very high and, therefore, possessed a higher water potential than the environments. Seeds of the other species either lost water (desorption) to the relative humidity chambers, or absorbed water ...

  13. SPS Ion Induced Desorption Experiment

    CERN Multimedia

    Maximilien Brice

    2003-01-01

    This experiment will give a study about the induced desorption from heavy ion (Indium ion run from week 45 in SPS T4-H8 area) impacting LHC type graphite collimator. 4 different samples are located in the 4 chambers 90° one to each other: pure graphite, graphite with copper coating, graphite with NEG coating, 316LN stainless steal (reference).

  14. Cooling water systems design using process integration

    CSIR Research Space (South Africa)

    Gololo, KV

    2010-09-01

    Full Text Available is synthesized using the mathematical optimization technique. This technique is based on superstructure in which all opportunities for cooling water reuse are explored. The cooling tower model is used to predict the thermal performance of the cooling towers....

  15. Nonisothermal desorption of droplets of complex compositions

    Directory of Open Access Journals (Sweden)

    Nakoryakov Vladimir E.

    2012-01-01

    Full Text Available This paper presents the process of nonstationary evaporation of aqueous solutions of LiBr-H2O, CaCl2-H2O, NaCl-H2O droplets on a horizontal heating surface. The following typical stages of heat and mass transfer depending on wall temperature have been considered: evaporation below boiling temperature and nucleate boiling. The significant decrease in desorption intensity with a rise of initial mass concentration of salt has been observed. Formation of a surface crystallization front at evaporation of a droplet has been detected. We have developed the experimental method for direct measurements of the mass of evaporating droplet.

  16. Sorption and desorption studies of chromium(VI) from nonviable cyanobacterium Nostoc muscorum biomass

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, V.K. [Department of Chemistry, Indian Institute of Technology Roorkee, Roorkee 247667 (India)], E-mail: vinodfcy@iitr.ernet.in; Rastogi, A. [Department of Chemistry, Indian Institute of Technology Roorkee, Roorkee 247667 (India)

    2008-06-15

    This communication presents results pertaining to the sorptive and desorptive studies carried out on chromium(VI) removal onto nonviable freshwater cyanobacterium (Nostoc muscorum) biomass. Influence of varying the conditions for removal of chromium(VI), such as the pH of aqueous solution, the dosage of biosorbent, the contact time with the biosorbent, the temperature for the removal of chromium, the effect of light metal ions and the adsorption-desorption studies were investigated. Sorption interaction of chromium on to cyanobacterial species obeyed both the first and the second-order rate equation and the experimental data showed good fit with both the Langmuir and freundlich adsorption isotherm models. The maximum adsorption capacity was 22.92 mg/g at 25 {sup o}C and pH 3.0. The adsorption process was endothermic and the values of thermodynamic parameters of the process were calculated. Various properties of the cyanobacterium, as adsorbent, explored in the characterization part were chemical composition of the adsorbent, surface area calculation by BET method and surface functionality by FTIR. Sorption-desorption of chromium into inorganic solutions and distilled water were observed and this indicated the biosorbent could be regenerated using 0.1 M HNO{sub 3} and EDTA with upto 80% recovery. The biosorbents were reused in five biosorption-desorption cycles without a significant loss in biosorption capacity. Thus, this study demonstrated that the cyanobacterial biomass N. muscorum could be used as an efficient biosorbent for the treatment of chromium(VI) bearing wastewater.

  17. Food selectivity and processing by the cold-water coral

    NARCIS (Netherlands)

    Van Oevelen, D.; Mueller, C.E.; Lundälv, T.; Middelburg, J.J.

    2016-01-01

    Cold-water corals form prominent reef ecosystemsalong ocean margins that depend on suspended resourcesproduced in surface waters. In this study, we investigatedfood processing of 13C and 15N labelled bacteria and algaeby the cold-water coral Lophelia pertusa. Coral respiration,tissue incorporation

  18. Efficacy of conventional drinking water treatment processes in ...

    African Journals Online (AJOL)

    2013-10-07

    Oct 7, 2013 ... statistical evidence could be displayed to suggest effective removal of geosmin in this conventional water treatment plant. With good ... drinking water treatment processes can effectively remove problem-causing phytoplankton as well as their associated ..... increasing the cost of water treatment significantly.

  19. Dispersive multi-walled carbon nanotubes extraction of benzenesulfonamides, benzotriazoles, and benzothiazoles from environmental waters followed by microwave desorption and HPLC-HESI-MS/MS.

    Science.gov (United States)

    Speltini, Andrea; Maraschi, Federica; Sturini, Michela; Contini, Matteo; Profumo, Antonella

    2017-11-01

    This work shows a novel analytical method for the simultaneous extraction of environmental emerging contaminants as benzenesulfonamides (BSAs), benzotriazoles (BTRs), and benzothiazoles (BTs) from water samples. Pristine multi-walled carbon nanotubes (MWCNTs), not yet tested for such analytes, are here employed as the sorbent phase for dispersive solid-phase extraction (d-SPE) followed by high-performance liquid chromatography/electrospray ionization tandem mass spectrometry (HPLC-HESI-MS/MS). Quantitative sorption is gained by treating 50 mL sample with 100 mg MWCNTs (2 g L-1) in 10 min contact, both in tap and raw river water. After sorption, the analytes are quantitatively desorbed by microwaves (20 min, 160 °C, 250 W) by using 5 mL methanol-ethylacetate-acetic acid (10:70:20, v/v), according to the indications obtained by a chemometric study. The extract is reduced to small volume before analysis, thus reaching overall enrichment factors up to 400. Recovery of the entire procedure, evaluated on tap and surface water samples spiked with 0.1/0.5-50 μg L-1 of each analyte, was in the range 70-116%, with excellent inter-day precision (RSD < 7%). Selectivity and firm analyte identification were assured by MRM detection, and suitable sensitivity was obtained for determination of these pollutants in actual matrices (experimental MDLs 30-170 ng L-1). The proposed analytical method was applied to the analysis of surface water samples, containing concentrations of these contaminants ranging from 100 ng L-1 to 2 μg L-1. Pristine MWCNTs proved to be a valid alternative to other commercial sorbents, both in terms of cost and sorption capacity. Graphical abstract Determination of benzenesulfonamides, benzotriazoles, and benzothiazoles in environmental waters by dispersive multi-walled carbon nanotube extraction prior HPLC-MS.

  20. Membrane-based processes for sustainable power generation using water.

    Science.gov (United States)

    Logan, Bruce E; Elimelech, Menachem

    2012-08-16

    Water has always been crucial to combustion and hydroelectric processes, but it could become the source of power in membrane-based systems that capture energy from natural and waste waters. Two processes are emerging as sustainable methods for capturing energy from sea water: pressure-retarded osmosis and reverse electrodialysis. These processes can also capture energy from waste heat by generating artificial salinity gradients using synthetic solutions, such as thermolytic salts. A further source of energy comes from organic matter in waste waters, which can be harnessed using microbial fuel-cell technology, allowing both wastewater treatment and power production.

  1. Membrane-based processes for sustainable power generation using water

    KAUST Repository

    Logan, Bruce E.

    2012-08-15

    Water has always been crucial to combustion and hydroelectric processes, but it could become the source of power in membrane-based systems that capture energy from natural and waste waters. Two processes are emerging as sustainable methods for capturing energy from sea water: pressure-retarded osmosis and reverse electrodialysis. These processes can also capture energy from waste heat by generating artificial salinity gradients using synthetic solutions, such as thermolytic salts. A further source of energy comes from organic matter in waste waters, which can be harnessed using microbial fuel-cell technology, allowing both wastewater treatment and power production. © 2012 Macmillan Publishers Limited. All rights reserved.

  2. Process for the biological purification of waste water

    DEFF Research Database (Denmark)

    1992-01-01

    Process for the biological purification of waste water by the activated sludge method, the waste water being mixed with recirculated sludge and being subjected to an anaerobic treatment, before the waste water thus treated is alternately subjected to anoxic and aerobic treatments and the waste...... water thus treated is led into a clarification zone for settling sludge, which sludge is recirculated in order to be mixed with the crude waste water. As a result, a simultaneous reduction of the content both of nitrogen and phosphorus of the waste water is achieved....

  3. Arsenic in industrial waste water from copper production technological process

    Directory of Open Access Journals (Sweden)

    Biljana Jovanović

    2013-12-01

    Full Text Available Investigation of arsenic in industrial waste water is of a great importance for environment. Discharge of untreated waste water from a copper production process results in serious pollution of surface water, which directly affects flora and fauna, as well as humans. There is a need for efficient and environmentally acceptable treament of waste waters containing heavy metals and arsenic. The paper presents an analyisis of the waste water from The Copper Smelter which is discharged into the Bor river. The expected arsenic content in treated waste water after using HDS procedure is also presented.

  4. The influence of various factors on the droplet desorption

    Science.gov (United States)

    Misyura, S. Y.; Morozov, V. S.

    2017-09-01

    Experimental data on sessile droplet desorption of aqueous salt solution of LiBr on a heated wall were implemented. High-temperature desorption of water-salt solutions in air atmosphere leads to significant difficulties at modeling heat and mass transfer. In this case, the evaporation rate multiply decreases with time and the diffusion coefficient, the desorption heat and the salt concentration change significantly. With the growth of salt concentration in solution from 10 % to 65 %, the steam partial pressure at the interface falls by dozens of times. In this study, we performed experiments in a wide range of salt concentrations and proposed a simple estimated method for calculating the mass flow. The resulting technique can predict the droplet solution behavior with a significant change in the partial vapor pressure on the droplet interphase with time.

  5. Desorption of toluene from modified clays using supercritical carbon dioxide

    Directory of Open Access Journals (Sweden)

    Carneiro D. G. P.

    2004-01-01

    Full Text Available The main objective of this work is to study the regeneration capacity of modified clays using supercritical fluid. These modified clays are used as organic compound adsorvents. The experimental step was done using a packed column with the clay contaminated by toluene. The results obtained showed the influence of the density of the supercritical CO2 and of the organic modifier in the desorption process. These data were modeled with first- and second-order models. Better results were obtained using the second-order model. This study makes possible the scale-up of the desorption process for regeneration of solid matrices using supercritical fluids.

  6. Nonthermal current-stimulated desorption of gases from carbon nanotubes.

    Science.gov (United States)

    Salehi-Khojin, Amin; Lin, Kevin Y; Field, Christopher R; Masel, Richard I

    2010-09-10

    The desorption of gases from carbon nanotubes is usually a slow process that limits the nanotubes' utility as sensors or as memristors. Here, we demonstrate that flow in the nanotube above the Poole-Frenkel conduction threshold can stimulate adsorbates to desorb without heating the sensor substantially. The method is general: alcohols, aromatics, amines, and phosphonates were all found to desorb. We postulate that the process is analogous to electron-stimulated desorption, but with an internally conducted rather than externally applied source of electrons.

  7. Adsorption and desorption of dissolved organic matter by carbon nanotubes: Effects of solution chemistry.

    Science.gov (United States)

    Engel, Maya; Chefetz, Benny

    2016-06-01

    Increasing use of carbon nanotubes (CNTs) has led to their introduction into the environment where they can interact with dissolved organic matter (DOM). This study focuses on solution chemistry effects on DOM adsorption/desorption processes by single-walled CNTs (SWCNTs). Our data show that DOM adsorption is controlled by the attachment of DOM molecules to the SWCNTs, and that the initial adsorption rate is dependent on solution parameters. Adsorbed amount of DOM at high ionic strength was limited, possibly due to alterations in SWCNT bundling. Desorption of DOM performed at low pH resulted in additional DOM adsorption, whereas at high pH, adsorbed DOM amount decreased. The extent of desorption conducted at increased ionic strength was dependent on pre-adsorbed DOM concentration: low DOM loading stimulated additional adsorption of DOM, whereas high DOM loading facilitated release of adsorbed DOM. Elevated ionic strength and increased adsorbed amount of DOM reduced the oxidation temperature of the SWCNTs, suggesting that changes in the assembly of the SWCNTs had occurred. Moreover, DOM-coated SWCNTs at increased ionic strength provided fewer sites for atrazine adsorption. This study enhances our understanding of DOM-SWCNT interactions in aqueous systems influenced by rapid changes in salinity, and facilitates potential use of SWCNTs in water-purification technologies. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Variable Temperature Infrared Spectroscopy Investigations of Benzoic Acid Desorption from Sodium and Calcium Montmorillonite Clays.

    Science.gov (United States)

    Nickels, Tara M; Ingram, Audrey L; Maraoulaite, Dalia K; White, Robert L

    2015-12-01

    Processes involved in thermal desorption of benzoic acid from sodium and calcium montmorillonite clays are investigated by using variable temperature diffuse reflection Fourier transform infrared spectroscopy (DRIFTS). By monitoring the temperature dependence of infrared absorbance bands while heating samples, subtle changes in molecular vibrations are detected and employed to characterize specific benzoic acid adsorption sites. Abrupt changes in benzoic acid adsorption site properties occur for both clay samples at about 125 °C. Difference spectra absorbance band frequency variations indicate that adsorbed benzoic acid interacts with interlayer cations through water bridges and that these interactions can be disrupted by the presence of organic anions, in particular, benzoate.

  9. Desorption of metals from Cetraria islandica (L. Ach. Lichen using solutions simulating acid rain

    Directory of Open Access Journals (Sweden)

    Čučulović Ana A.

    2014-01-01

    Full Text Available Desorption of metals K, Al, Ca, Mg, Fe, Ba, Zn, Mn, Cu and Sr from Cetraria islandica (L. with solutions whose composition was similar to that of acid rain, was investigated. Desorption of metals from the lichen was performed by five successive desorption processes. Solution mixtures containing H2SO4, HNO3 and H2SO4-HNO3 were used for desorption. Each solution had three different pH values: 4.61, 5.15 and 5.75, so that the desorptions were performed with nine different solutions successively five times, always using the same solution volume. The investigated metals can be divided into two groups. One group was comprised of K, Ca and Mg, which were desorbed in each of the five desorption processes at all pH values used. The second group included Al, Fe, Zn, Ba, Mn and Sr; these were not desorbed in each individual desorption and not at all pH values, whereas Cu was not desorbed at all under any circumstances. Using the logarithmic dependence of the metal content as a function of the desorption number, it was found that potassium builds two types of links and is connected with weaker links in lichen. Potassium is completely desorbed, 80% in the first desorption, and then gradually in the following desorptions. Other metals are linked with one weaker link (desorption 1-38% and with one very strong link (desorption below the metal detection limit. [Projekat Ministarstva nauke Republike Srbije, br. III43009 i br. ON 172019

  10. Study of the mechanisms of heavy-ion induced desorption on accelerator-relevant materials; Untersuchung der Mechanismen schwerioneninduzierter Desorption an beschleunigerrelevanten Materialien

    Energy Technology Data Exchange (ETDEWEB)

    Bender, Markus

    2008-02-22

    The ion beam loss induced desorption is a performance limitation for low charge state heavy ion accelerators. If charge exchanged projectile ions get lost onto the beam pipe, desorption of gas is stimulated resulting in a pressure increase inside of the synchrotron and thus, a dramatically reduction of the beam life time. To minimize the amount of desorbed gas an experimental program has been started to measure the desorption yields (released gas molecules per incident ion) of various materials and different projectile ions. The present work is a contribution to the understanding of the physical processes behind the ion beam loss induced desorption. The yield measurements by the pressure rise method have been combined for the rst time with in situ ion beam analysis technologies such as ERDA and RBS. With this unique method the desorption behavior of a sample can be correlated to its surface and bulk properties. The performed experiments with 1,4 MeV/u Xenon-Ions show that the ion induced desorption is mainly a surface effect. Sputtered oxide layers or impurities do not contribute to the desorbed gas significantly. Nevertheless bulk properties play an important role in the desorption strength. Pure metallic samples desorb less gas than isolating materials under swift heavy ion irradiation. From the experimental results it was possible to estimate the desorption yields of various materials under ion bombardment by means of an extended inelastic thermal-spike-model. The extension is the combination of the thermal-spike's temperature map with thermal desorption. Within this model the ion induced desorption can be regarded as the release of adsorbates from a transient overheated spot on the samples surface around the ion impact. Finally a copper substrate with a gold coated surface was developed and proposed as a suitable material for a beam loss collimator with minimum desorption to ensure the performance of GSI's SIS18 in high current beam operation. (orig.)

  11. Coal liquefaction process streams characterization and evaluation. Characterization of coal-derived materials by field desorption mass spectrometry, two-dimensional nuclear magnetic resonance, supercritical fluid extraction, and supercritical fluid chromatography/mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, J.A.; Linehan, J.C.; Robins, W.H. [Battelle Pacific Northwest Lab., Richland, WA (United States)

    1992-07-01

    Under contract from the DOE , and in association with CONSOL Inc., Battelle, Pacific Northwest Laboratory (PNL) evaluated four principal and several complementary techniques for the analysis of non-distillable direct coal liquefaction materials in support of process development. Field desorption mass spectrometry (FDMS) and nuclear magnetic resonance (NMR) spectroscopic methods were examined for potential usefulness as techniques to elucidate the chemical structure of residual (nondistillable) direct coal liquefaction derived materials. Supercritical fluid extraction (SFE) and supercritical fluid chromatography/mass spectrometry (SFC/MS) were evaluated for effectiveness in compound-class separation and identification of residual materials. Liquid chromatography (including microcolumn) separation techniques, gas chromatography/mass spectrometry (GC/MS), mass spectrometry/mass spectrometry (MS/MS), and GC/Fourier transform infrared (FTIR) spectroscopy methods were applied to supercritical fluid extracts. The full report authored by the PNL researchers is presented here. The following assessment briefly highlights the major findings of the project, and evaluates the potential of the methods for application to coal liquefaction materials. These results will be incorporated by CONSOL into a general overview of the application of novel analytical techniques to coal-derived materials at the conclusion of CONSOL`s contract.

  12. Process engineering applied to receiving waters

    DEFF Research Database (Denmark)

    Harremoës, Poul

    1973-01-01

    Processes in the media, which recieve waste, must be included in the sphere of interest within industry's environmental consciousness. Pollution problems are not very simple and should thus not be dealt with in too simple a fashion. Chemical engineers are very well suited to deal...

  13. Hydrogeophysical monitoring of water infiltration processes

    Science.gov (United States)

    Bevilacqua, Ivan; Cassiani, Giorgio; Deiana, Rita; Canone, Davide; Previati, Maurizio

    2010-05-01

    Non-invasive subsurface monitoring is growing in the last years. Techniques like ground-penetrating radar (GPR) and electrical resistivity tomography (ERT) can be useful in soil water content monitoring (e.g., Vereecken et al., 2006). Some problems remain (e.g. spatial resolution), but the scale is consistent with many applications and hydrological models. The research has to to provide even more quantitative tools, without remaining in the qualitative realm. This is a very crucial step in the way to provide data useful for hydrological modeling. In this work a controlled field infiltration experiment has been done in August 2009 in the experimental site of Grugliasco, close to the Agricultural Faculty of the University of Torino, Italy. The infiltration has been monitored in time lapse by ERT, GPR, and TDR (Time Domain Reflectometry). The sandy soil characteristics of the site has been already described in another experiment [Cassiani et al. 2009a].The ERT was èperformed in dipole-dipole configuration, while the GPR had 100 MHz and 500 MHz antennas in WARR configuration. The TDR gages had different lengths. The amount of water which was sprinkled was also monitored in time.Irrigation intensity has been always smaller than infiltration capacity, in order not toh ave any surface ponding. Spectral induced polarization has been used to infer constitutive parameters from soil samples [Cassiani et al. 2009b]. 2D Richards equation model (Manzini and Ferraris, 2004) has been then calibrated with the measurements. References. Cassiani, G., S. Ferraris, M. Giustiniani, R. Deiana and C.Strobbia, 2009a, Time-lapse surface-to-surface GPR measurements to monitor a controlled infiltration experiment, in press, Bollettino di Geofisica Teorica ed Applicata, Vol. 50, 2 Marzo 2009, pp. 209-226. Cassiani, G., A. Kemna, A.Villa, and E. Zimmermann, 2009b, Spectral induced polarization for the characterization of free-phase hydrocarbon contamination in sediments with low clay content

  14. Moisture sorption–desorption characteristics and the corresponding thermodynamic properties of carvedilol phosphate

    Directory of Open Access Journals (Sweden)

    Ravikiran Allada

    2017-01-01

    Full Text Available Aims: Carvedilol phosphate (CDP is a nonselective beta-blocker used for the treatment of heart failures and hypertension. In this work, moisture sorption–desorption characteristics and thermodynamic properties of CDP have been investigated. Materials and Methods: The isotherms were determined using dynamic vapor sorption analyzer at different humidity conditions (0%–90% relative humidity and three pharmaceutically relevant temperatures (20°C, 30°C, and 40°C. The experimental sorption data determined were fitted to various models, namely, Brunauer–Emmett–Teller; Guggenheim-Anderson-De Boer (GAB; Peleg; and modified GAB. Isosteric heats of sorption were evaluated through the direct use of sorption isotherms by means of the Clausius-Clapeyron equation. Statistical Analysis Used: The sorption model parameters were determined from the experimental sorption data using nonlinear regression analysis, and mean relative percentage deviation (P, correlation (Correl, root mean square error, and model efficiency were considered as the criteria to select the best fit model. Results: The sorption–desorption isotherms have sigmoidal shape – confirming to Type II isotherms. Based on the statistical data analysis, modified GAB model was found to be more adequate to explain sorption characteristics of CDP. It is noted that the rate of adsorption and desorption is specific to the temperature at which it was being studied. It is observed that isosteric heat of sorption decreased with increasing equilibrium moisture content. Conclusions: The calculation of the thermodynamic properties was further used to draw an understanding of the properties of water and energy requirements associated with the sorption behavior. The sorption–desorption data and the set of equations are useful in the simulation of processing, handling, and storage of CDP and further behavior during manufacture and storage of CDP formulations.

  15. Moisture Sorption–desorption Characteristics and the Corresponding Thermodynamic Properties of Carvedilol Phosphate

    Science.gov (United States)

    Allada, Ravikiran; Maruthapillai, Arthanareeswari; Palanisamy, Kamaraj; Chappa, Praveen

    2017-01-01

    Aims: Carvedilol phosphate (CDP) is a nonselective beta-blocker used for the treatment of heart failures and hypertension. In this work, moisture sorption–desorption characteristics and thermodynamic properties of CDP have been investigated. Materials and Methods: The isotherms were determined using dynamic vapor sorption analyzer at different humidity conditions (0%–90% relative humidity) and three pharmaceutically relevant temperatures (20°C, 30°C, and 40°C). The experimental sorption data determined were fitted to various models, namely, Brunauer–Emmett–Teller; Guggenheim-Anderson-De Boer (GAB); Peleg; and modified GAB. Isosteric heats of sorption were evaluated through the direct use of sorption isotherms by means of the Clausius-Clapeyron equation. Statistical Analysis Used: The sorption model parameters were determined from the experimental sorption data using nonlinear regression analysis, and mean relative percentage deviation (P), correlation (Correl), root mean square error, and model efficiency were considered as the criteria to select the best fit model. Results: The sorption–desorption isotherms have sigmoidal shape – confirming to Type II isotherms. Based on the statistical data analysis, modified GAB model was found to be more adequate to explain sorption characteristics of CDP. It is noted that the rate of adsorption and desorption is specific to the temperature at which it was being studied. It is observed that isosteric heat of sorption decreased with increasing equilibrium moisture content. Conclusions: The calculation of the thermodynamic properties was further used to draw an understanding of the properties of water and energy requirements associated with the sorption behavior. The sorption–desorption data and the set of equations are useful in the simulation of processing, handling, and storage of CDP and further behavior during manufacture and storage of CDP formulations. PMID:28584488

  16. Moisture Sorption-desorption Characteristics and the Corresponding Thermodynamic Properties of Carvedilol Phosphate.

    Science.gov (United States)

    Allada, Ravikiran; Maruthapillai, Arthanareeswari; Palanisamy, Kamaraj; Chappa, Praveen

    2017-01-01

    Carvedilol phosphate (CDP) is a nonselective beta-blocker used for the treatment of heart failures and hypertension. In this work, moisture sorption-desorption characteristics and thermodynamic properties of CDP have been investigated. The isotherms were determined using dynamic vapor sorption analyzer at different humidity conditions (0%-90% relative humidity) and three pharmaceutically relevant temperatures (20°C, 30°C, and 40°C). The experimental sorption data determined were fitted to various models, namely, Brunauer-Emmett-Teller; Guggenheim-Anderson-De Boer (GAB); Peleg; and modified GAB. Isosteric heats of sorption were evaluated through the direct use of sorption isotherms by means of the Clausius-Clapeyron equation. The sorption model parameters were determined from the experimental sorption data using nonlinear regression analysis, and mean relative percentage deviation (P), correlation (Correl), root mean square error, and model efficiency were considered as the criteria to select the best fit model. The sorption-desorption isotherms have sigmoidal shape - confirming to Type II isotherms. Based on the statistical data analysis, modified GAB model was found to be more adequate to explain sorption characteristics of CDP. It is noted that the rate of adsorption and desorption is specific to the temperature at which it was being studied. It is observed that isosteric heat of sorption decreased with increasing equilibrium moisture content. The calculation of the thermodynamic properties was further used to draw an understanding of the properties of water and energy requirements associated with the sorption behavior. The sorption-desorption data and the set of equations are useful in the simulation of processing, handling, and storage of CDP and further behavior during manufacture and storage of CDP formulations.

  17. Desorption of isopropyl alcohol from adsorbent with non-thermal plasma.

    Science.gov (United States)

    Shiau, Chen Han; Pan, Kuan Lun; Yu, Sheng Jen; Yan, Shaw Yi; Chang, Moo Been

    2017-09-01

    Effective desorption of isopropyl alcohol (IPA) from adsorbents with non-thermal plasma is developed. In this system, IPA is effectively adsorbed with activated carbon while dielectric barrier discharge is applied to replace the conventional thermal desorption process to achieve good desorption efficiency, making the treatment equipment smaller in size. Various adsorbents including molecular sieves and activated carbon are evaluated for IPA adsorption capacity. The results indicate that BAC has the highest IPA adsorption capacity (280.31 mg IPA/g) under the operating conditions of room temperature, IPA of 400 ppm, and residence time of 0.283 s among 5 adsorbents tested. For the plasma desorption process, the IPA selectivity of 89% is achieved with BAC as N2 is used as desorbing gas. In addition, as air or O2 is used as desorbing gas, the IPA desorption concentration is reduced, because air and O2 plasmas generate active species to oxidize IPA to form acetone, CO2, and even CO. Furthermore, the results of the durability test indicate that the amount of IPA desorbed increases with increasing desorption times and plasma desorption process has a higher energy efficiency if compared with thermal desorption. Overall, this study indicates that non-thermal plasma is a viable process for removing VOCs to regenerate adsorbent.

  18. Electronically driven adsorbate excitation mechanism in femtosecond-pulse laser desorption

    DEFF Research Database (Denmark)

    Brandbyge, Mads; Hedegård, Per; Heinz, T. F.

    1995-01-01

    Femtosecond-pulse laser desorption is a process in which desorption is driven by a subpicosecond temperature pulse of order 5000 K in the substrate-adsorbate electron system, whose energy is transferred into the adsorbate center-of-mass degrees of freedom by a direct coupling mechanism. We presen...

  19. Development of methods for thermal desorption of iodine from carbon sorbent

    Science.gov (United States)

    Shapovalova, E. A.; Hlopotov, R. A.

    2017-10-01

    The paper studies and proposes four circuits of thermal iodine desorption from coal, which excludes the use of chemical reagents. The method allows for the sublimation of iodine from coal, avoiding the stage of pre-concentration and crystallization of crude iodine-concentrate. The proposed solution allows carrying out the process of thermal desorption of iodine without unloading it from the reactor.

  20. Wet oxidation processes for water pollution remediation

    OpenAIRE

    García Molina, Verónica

    2006-01-01

    The main objective of this work was to test the efficiency of wet oxidation processes when treating several types of aqueous wastes. On one side its performance for the abatement of chloro-organic aromatic toxic pollutants, such as 4-chlorophenol and 2,4-dichlorophenol has been studied. On the other hand, wastewater from pulp and paper mills, which has been reported to be an indirect source of entry of chlorophenols in the aquatic environment, has been investigated. More in detail, it has bee...

  1. Integrated water management system - Description and test results. [for Space Station waste water processing

    Science.gov (United States)

    Elden, N. C.; Winkler, H. E.; Price, D. F.; Reysa, R. P.

    1983-01-01

    Water recovery subsystems are being tested at the NASA Lyndon B. Johnson Space Center for Space Station use to process waste water generated from urine and wash water collection facilities. These subsystems are being integrated into a water management system that will incorporate wash water and urine processing through the use of hyperfiltration and vapor compression distillation subsystems. Other hardware in the water management system includes a whole body shower, a clothes washing facility, a urine collection and pretreatment unit, a recovered water post-treatment system, and a water quality monitor. This paper describes the integrated test configuration, pertinent performance data, and feasibility and design compatibility conclusions of the integrated water management system.

  2. Femtosecond laser pulse induced desorption: A molecular dynamics simulation

    Energy Technology Data Exchange (ETDEWEB)

    Lončarić, Ivor, E-mail: ivor.loncaric@gmail.com [Centro de Física de Materiales CFM/MPC (CSIC-UPV/EHU), P. Manuel de Lardizabal 5, 20018 San Sebastián (Spain); Alducin, Maite [Centro de Física de Materiales CFM/MPC (CSIC-UPV/EHU), P. Manuel de Lardizabal 5, 20018 San Sebastián (Spain); Donostia International Physics Center DIPC, P. Manuel de Lardizabal 4, 20018 San Sebastián (Spain); Saalfrank, Peter [Institut für Chemie, Universität Potsdam, Karl-Liebknecht-Strasse 24-25, D-14476 Potsdam (Germany); Donostia International Physics Center DIPC, P. Manuel de Lardizabal 4, 20018 San Sebastián (Spain); Juaristi, J. Iñaki [Departamento de Física de Materiales, Facultad de Químicas, Universidad del País Vasco (UPV/EHU), Apartado 1072, 20080 San Sebastián (Spain); Centro de Física de Materiales CFM/MPC (CSIC-UPV/EHU), P. Manuel de Lardizabal 5, 20018 San Sebastián (Spain); Donostia International Physics Center DIPC, P. Manuel de Lardizabal 4, 20018 San Sebastián (Spain)

    2016-09-01

    In recent simulations of femtosecond laser induced desorption of molecular oxygen from the Ag(110) surface, it has been shown that depending on the properties (depth and electronic environment) of the well in which O{sub 2} is adsorbed, the desorption can be either induced dominantly by hot electrons or via excitations of phonons. In this work we explore whether the ratios between the desorption yields from different adsorption wells can be tuned by changing initial surface temperature and laser pulse properties. We show that the initial surface temperature is an important parameter, and that by using low initial surface temperatures the electronically mediated process can be favored. In contrast, laser properties seem to have only a modest influence on the results.

  3. Air flotation treatment of salmon processing waste water

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This paper discusses methods for the reduction of the pollution strength of salmon processing waste water. Past research has indicated the success of air pressure...

  4. Quantification of water usage at a South African platinum processing ...

    African Journals Online (AJOL)

    Quantification of water usage at a South African platinum processing plant. EL Haggard1, CM Sheridan1 and KG Harding1*. 1Industrial and Mining Water Research Unit (IMWaRU), School of Chemical and Metallurgical Engineering, University of the Witwatersrand,. Johannesburg, Private Bag 3, Wits 2050, South Africa.

  5. Water-integrated scheduling of batch process plants

    NARCIS (Netherlands)

    Pulluru, Sai Jishna; Akkerman, Renzo

    2017-01-01

    Efficient water management is becoming increasingly important in production systems, but companies often do not have any concrete strategies to implement. While there are numerous technological options for improving water efficiency in process plants, there is a lack of effective decision support to

  6. Industrial water and effluent management in the milk processing industry

    CSIR Research Space (South Africa)

    Funke, JW

    1970-01-01

    Full Text Available One of the most important commodities used in any food-processing industry is water which must be of the right quality. Water which comes into direct contact with milk or milk products must meet standards which are even stricter than those for a...

  7. Toxicity Evaluation and Cytogenetic Screening of Process Water 2

    African Journals Online (AJOL)

    Dr. K.J. Umar

    ABSTRACT: The effect of toxic substances on aquatic lives from a wastewater indiscriminately discharged into the environment during oil ... treatment of process water before its discharge into water bodies to avoid cyto-genetic damages to aquatic lives. Keywords: ..... of the pesticides phosdrin and bladex in. Tradescantia ...

  8. Analytical solution for soil water redistribution during evaporation process.

    Science.gov (United States)

    Teng, Jidong; Yasufuku, Noriyuki; Liu, Qiang; Liu, Shiyu

    2013-01-01

    Simulating the dynamics of soil water content and modeling soil water evaporation are critical for many environmental and agricultural strategies. The present study aims to develop an analytical solution to simulate soil water redistribution during the evaporation process. This analytical solution was derived utilizing an exponential function to describe the relation of hydraulic conductivity and water content on pressure head. The solution was obtained based on the initial condition of saturation and an exponential function to model the change of surface water content. Also, the evaporation experiments were conducted under a climate control apparatus to validate the theoretical development. Comparisons between the proposed analytical solution and experimental result are presented from the aspects of soil water redistribution, evaporative rate and cumulative evaporation. Their good agreement indicates that this analytical solution provides a reliable way to investigate the interaction of evaporation and soil water profile.

  9. The Effects of composts on adsorption-desorption of three ...

    African Journals Online (AJOL)

    Michael Horsfall

    (1/n des). @JASEM. Pesticides adsorption and desorption are the key processes determining whether pesticide used will have any impact on environmental quality. For most of the pesticides soil organic matter and clay contents are the most important properties which affect the sorption and transformation (Durovic et al., ...

  10. The efficacy of electrolysed oxidising water for inactivating spoilage microorganisms in process water and on minimally processed vegetables.

    Science.gov (United States)

    Ongeng, Duncan; Devlieghere, Frank; Debevere, Johan; Coosemans, Jozef; Ryckeboer, Jaak

    2006-06-15

    The efficacy of Electrolysed Oxidising Water (EOW) for inactivating spoilage microorganisms in process water and on minimally processed vegetables was investigated. The direct effect of EOW on three important spoilage bacteria namely; Pseudomonas fluorescens, Pantoea agglomerans or Rahnella aquatilis was determined by inoculating tap water or "artificial process water" with approximately 8 log CFU/ml pure culture and electrolysing the resultant solutions. The three bacteria were each reduced to undetectable levels at low (0.5 A) and relatively higher levels (1.0 A) of current in tap water and "artificial process water", respectively. The residual effect of EOW on P. fluorescens, P. agglomerans or R. aquatilis was determined by incubating at room temperature 1 ml (approximately 9 log CFU/ml) pure culture suspensions in 9 ml of EOW-T (EOW produced from tap water), EOW-A (EOW produced from "artificial process water" supplemented with approximately 60.7 mg Cl(-)/l and 39.3 mg Na(+)/l) or deionised water (control) for 0, 15, 45 or 90 min. The bactericidal activity of both EOW-T and EOW-A increased with the concentration of free oxidants and incubation period and the three bacteria were completely reduced at free oxidants-incubation period combinations of 3.88 mg/l-45 min and 5.1 mg/l-90 min in EOW-T and EOW-A, respectively. Two types of industrial vegetable process water; salad-mix and soup process water, which had each a total psychrotrophic count of approximately 8 log CFU/ml were then electrolysed. Without any NaCl addition, only 1.2 and 2.1 log reductions of the psychrotrophs in soup and salad-mix process water was attained respectively. Supplementation of the process water with approximately 60.7 mg Cl(-)/l and 39.3 mg Na(+)/l afterwards resulted in complete reduction of the psychrotrophic count in both process waters, but soup process water required relatively higher levels of current compared to salad-mix water. Finally, fresh-cut lettuce was washed in EOW

  11. Microwaves energy in curing process of water glass molding sands

    Directory of Open Access Journals (Sweden)

    Granat K.

    2007-01-01

    Full Text Available This work presents the results of investigation of microwave heating on hardening process of water glass molding sands. Essential influence of this heating process on basic properties such as: compression, bending and tensile strength as well as permeability and abrasion resistance has been found. It has been proved, that all investigated sorts of sodium water glass with a module between 2.0 and 3.3 can be used as a binder of molding sands in microwave curing process. It has been found during analysis of research results of sands with 2.5 % water glass addition that they are practically the same as in case of identical molding sands dried for 120 minutes at the temperature of 110°C, used for comparative purposes. Application of microwave curing of molding sands with water glass, however, guarantees reduction of hardening time (from 120 to 4 minutes as well as significant reduction of energy consumption. Attempts of two stage hardening of the investigated water glass molding sands have also been carried out, that is after an initial hardening during a classical CO2 process (identical sands have also been tested for comparison after CO2 blowing process and additional microwave heating. It has been found that application of this kind of treatment for curing sands with 2.5 % sodium water glass content and module from 2.0 up to 3.3 results in the improvement of properties in comparison to classical CO2 process.

  12. Processing of water level derived from water pressure data at the Time Series Station Spiekeroog

    OpenAIRE

    Holinde, L.; Badewien, T. H.; Freund, J. A.; E. V. Stanev; Zielinski, O.

    2015-01-01

    The quality of water level time series data strongly varies with periods of high- and low-quality sensor data. In this paper we are presenting the processing steps which were used to generate high-quality water level data from water pressure measured at the Time Series Station (TSS) Spiekeroog. The TSS is positioned in a tidal inlet between the islands of Spiekeroog and Langeoog in the East Frisian Wadden Sea (southern North Sea). The processing steps will cover sensor drift...

  13. An alternative process to treat boiler feed water for reuse.

    Science.gov (United States)

    Guirgis, Adel; Ghosh, Jyoti P; Achari, Gopal; Langford, Cooper H; Banerjee, Daliya

    2012-09-01

    A bench-scale process to treat boiler feed water for reuse in steam generation was developed. Industrial water samples from a steam-assisted gravity drainage plant in northern Alberta, Canada, were obtained and samples characterized. The technology, which consists of coagulation-settling to remove oil/grease and particulates followed by an advanced oxidative treatment, led to clean water samples with negligible organic carbon. Coagulation followed by settling removed most particulates and some insoluble organics. The advanced oxidative treatment removed any remaining color in the samples, decreased the organic content to near-zero, and provided water ready for reuse.

  14. Adsorption and laser-induced desorption of dimethylcadmium from silicon

    Science.gov (United States)

    Simonov, Alexander P.; Varakin, Vladimir N.

    1990-10-01

    The dynamics of Cd (cH ) 2 chemisorption and spontaneous decomposit ion on n-type 51(100) with native surface oxide the pathwa and efficiencies of the adsorbate desorption due to the absorption of the XeC1 laser radiation by silicon have been examined using laser-induced desorption miss spectrorrtry (LIDMS ) . The k inetics of these sur face processes has been found to depend on the preceding laser irradiation of the surface. The extremely fast chemisorption and efficient decomposition of the parent rrlecules have been observed on the irradiated silicon surface. The competition between intact dissociative and recombination desorption pathways was responsible for the observed laser fluence dependences of the desorption of Cd(CI-6) and i ts fragments. 1 . INTROOIJCTIct4 1 . 1 . Laser chemical vapour depos ition (LCVD). Laser-induced deposition of thin filme on solid surfaces by using volatile organometallic precursors has been the subject of numerous investigations in the 8Os2. Due to the spatial/temporal localization of laser radiation and the resonant nature of laser-rr1ecule interaction this deposition technique has such attractive features as submicrometer resolution of deposits high film growth rate and high quality lowtemperature processing. The deposition process can be controlled by varying the laser parameters (wavelength fluence beam spot on the substrate surface scanning speed ). A var iety of mater ials can be depos I ted using LCVD. Of special interest for microelectronics is the deposition of

  15. Water-Energy Correlations: Analysis of Water Technologies, Processes and Systems in Rural and Urban India

    Science.gov (United States)

    Murumkar, A. R.; Gupta, S.; Kaurwar, A.; Satankar, R. K.; Mounish, N. K.; Pitta, D. S.; Virat, J.; Kumar, G.; Hatte, S.; Tripathi, R. S.; Shedekar, V.; George, K. J.; Plappally, A. K.

    2015-12-01

    In India, the present value of water, both potable and not potable, bears no relation to the energy of water production. However, electrical energy spent on ground water extraction alone is equivalent to the nation's hydroelectric capacity of 40.1 GWh. Likewise, desalinating 1m3 water of the Bay of Bengal would save three times the energy for potable ground water extraction along the coast of the Bay. It is estimated that every second woman in rural India expends 0.98 kWhe/m3/d for bringing water for household needs. Yet, the water-energy nexus remains to be a topic which is gravely ignored. This is largely caused by factors such as lack of awareness, defective public policies, and intrusive cultural practices. Furthermore, there are instances of unceasing dereliction towards water management and maintenance of the sparsely distributed water and waste water treatment plants across the country. This pollutes the local water across India apart from other geogenic impurities. Additionally, product aesthetics and deceptive advertisements take advantage of the abulia generated by users' ignorance of technical specifications of water technologies and processes in mismanagement of water use. Accordingly, urban residents are tempted to expend on energy intensive water technologies at end use. This worsens the water-energy equation at urban households. Cooking procedures play a significant role in determining the energy expended on water at households. The paper also evaluates total energy expense involved in cultivating some major Kharif and Rabi crops. Manual and traditional agricultural practices are more prominent than mechanized and novel agricultural techniques. The specific energy consumption estimate for different water technologies will help optimize energy expended on water in its life cycles. The implication of the present study of water-energy correlation will help plan and extend water management infrastructure at different locations across India.

  16. Review of Water Consumption and Water Conservation Technologies in the Algal Biofuel Process.

    Science.gov (United States)

    Tu, Qingshi; Lu, Mingming; Thiansathit, Worrarat; Keener, Tim C

    2016-01-01

    Although water is one of the most critical factors affecting the sustainable development of algal biofuels, it is much less studied as compared to the extensive research on algal biofuel production technologies. This paper provides a review of the recent studies on water consumption of the algae biofuel process and presents the water conservation technologies applicable at different stages of the algal biofuel process. Open ponds tend to have much higher water consumption (216 to 2000 gal/gal) than photobioreactors (25 to 72 gal/gal). Algae growth accounts for the highest water consumption (165 to 2000 gal/gal) in the open pond system. Water consumption during harvesting, oil extraction, and biofuel conversion are much less compared with the growth stage. Potential water conservation opportunities include technology innovations and better management practices at different stages of algal biofuel production.

  17. Analysis of paper machine process waters; Paperikoneen prosessivesianalytiikka - MPKT 09

    Energy Technology Data Exchange (ETDEWEB)

    Knuutinen, J.; Alen, R.; Harjula, P.; Kilpinen, J.; Pallonen, R.; Jurvela, V.

    1998-12-31

    The closure of paper machine circuits demands a better knowledge of the chemical structures and behaviour of organic compounds in pulp mill process waters. Nonionic or negatively charged detrimental substances (anionic trash) which will eventually cause runnability. Paper quality problems are of special interest. The main purpose of the project was to develop routine `fingerprint` analytical procedures to study various process waters. Our major interest was focused on low molecular weight carboxylic acids, carbohydrates and lignin based material. The `fingerprints` (chromatograms and electropherograms) can be used to differentiate various process waters or to find out changes between the composition of organic compounds in various stages of the papermaking process. Until now the most characteristic `fingerprints` were obtained by capillary zone electrophoresis (CZE) and by pyrolysis - gas chromatography - mass spectrometry (Py-GC/MS). Examples of using these techniques are briefly discussed. (orig.)

  18. Synthesis and Design of Integrated Process and Water Networks

    DEFF Research Database (Denmark)

    Handani, Zainatul B.; Quaglia, Alberto; Gani, Rafiqul

    2015-01-01

    possible options with respect to the topology of the process and water networks, leading to Mixed Integer Non Linear Programming (MINLP) problem. A solution strategy to solve the multi-network problem accounts explicitly the interactions between the networks by selecting suitable technologies in order...... to transform raw materials into products and produce clean water to be reused in the process at the early stage of design. Since the connection between the process network and the wastewater treatment network is not a straight forward connection, a new converter interval is introduced in order to convert......This work presents the development of a systematic framework for a simultaneous synthesis and design of process and water networks using the superstructure-based optimization approach. In this framework, a new superstructure combining both networks is developed by attempting to consider all...

  19. Process Control for Precipitation Prevention in Space Water Recovery Systems

    Science.gov (United States)

    Sargusingh, Miriam; Callahan, Michael R.; Muirhead, Dean

    2015-01-01

    The ability to recover and purify water through physiochemical processes is crucial for realizing long-term human space missions, including both planetary habitation and space travel. Because of their robust nature, rotary distillation systems have been actively pursued by NASA as one of the technologies for water recovery from wastewater primarily comprised of human urine. A specific area of interest is the prevention of the formation of solids that could clog fluid lines and damage rotating equipment. To mitigate the formation of solids, operational constraints are in place that limits such that the concentration of key precipitating ions in the wastewater brine are below the theoretical threshold. This control in effected by limiting the amount of water recovered such that the risk of reaching the precipitation threshold is within acceptable limits. The water recovery limit is based on an empirically derived worst case wastewater composition. During the batch process, water recovery is estimated by monitoring the throughput of the system. NASA Johnson Space Center is working on means of enhancing the process controls to increase water recovery. Options include more precise prediction of the precipitation threshold. To this end, JSC is developing a means of more accurately measuring the constituent of the brine and/or wastewater. Another means would be to more accurately monitor the throughput of the system. In spring of 2015, testing will be performed to test strategies for optimizing water recovery without increasing the risk of solids formation in the brine.

  20. OPTIMIZATION OF FLOCCULATION PROCESS BY MICROBIAL COAGULANT IN RIVER WATER

    Directory of Open Access Journals (Sweden)

    Fatin Nabilah Murad

    2017-12-01

    Full Text Available The existing process of coagulation and flocculation are using chemicals that known as cationic coagulant such as alum, ferric sulfate, calcium oxide, and organic polymers.  Thus, this study concentrates on optimizing of flocculation process by microbial coagulant in river water. Turbidity and suspended solids are the main constraints of river water quality in Malaysia. Hence, a study is proposed to produce microbial coagulants isolated locally for river water treatment. The chosen microbe used as the bioflocculant producer is Aspergillus niger. The parameters to optimization in the flocculation process were pH, bioflocculant dosage and effluent concentration. The research was done in the jar test process and the process parameters for maximum turbidity removal was validated. The highest flocculating activity was obtained on day seven of cultivation in the supernatant. The optimum pH and bioflocculant dosage for an optimize sedimentation process were between 4-5 and 2-3 mL for 0.3 g/L of effluent concentration respectively. The model was validated by using a river water sample from Sg. Pusu and the result showed that the model was acceptable to evaluate the bioflocculation process.

  1. Stable Isotope Systematics of Coalbed Gas during Desorption and Production

    Directory of Open Access Journals (Sweden)

    Martin Niemann

    2017-06-01

    Full Text Available The stable carbon isotope ratios of coalbed methane (CBM demonstrate diagnostic changes that systematically vary with production and desorption times. These shifts can provide decisive, predictive information on the behaviour and potential performance of CBM operations. Samples from producing CBM wells show a general depletion in 13C-methane with increasing production times and corresponding shifts in δ13C-CH4 up to 35.8‰. Samples from canister desorption experiments show mostly enrichment in 13C for methane with increasing desorption time and isotope shifts of up to 43.4‰. Also, 13C-depletion was observed in some samples with isotope shifts of up to 32.1‰. Overall, the magnitudes of the observed isotope shifts vary considerably between different sample sets, but also within samples from the same source. The δ13C-CH4 values do not have the anticipated signature of methane generated from coal. This indicates that secondary processes, including desorption and diffusion, can influence the values. It is also challenging to deconvolute these various secondary processes because their molecular and isotope effects can have similar directions and/or magnitudes. In some instances, significant alteration of CBM gases has to be considered as a combination of secondary alteration effects.

  2. Simultaneous effect of dissolved organic carbon, surfactant, and organic acid on the desorption of pesticides investigated by response surface methodology

    DEFF Research Database (Denmark)

    Trinh, Ha Thu; Duong, Hanh Thi; Ta, Thao Thi

    2017-01-01

    Desorption of pesticides (fenobucarb, endosulfan, and dichlorodiphenyltrichloroethane (DDT)) from soil to aqueous solution with the simultaneous presence of dissolved organic carbon (DOC), sodium dodecyl sulfate (SDS), and sodium oxalate (Oxa) was investigated in batch test by applying a full...... caused the minimum desorption. This point at conditions of concern for flooding water is high content of organic compounds causing potentially high contamination by desorption, and the remarkably lower desorption at organic matter-free conditions. The suspended organic matter is one of the common...

  3. Innovative Fresh Water Production Process for Fossil Fuel Plants

    Energy Technology Data Exchange (ETDEWEB)

    James F. Klausner; Renwei Mei; Yi Li; Jessica Knight; Venugopal Jogi

    2005-09-01

    This project concerns a diffusion driven desalination (DDD) process where warm water is evaporated into a low humidity air stream, and the vapor is condensed out to produce distilled water. Although the process has a low fresh water to feed water conversion efficiency, it has been demonstrated that this process can potentially produce low cost distilled water when driven by low grade waste heat. This report describes the annual progress made in the development and analysis of a Diffusion Driven Desalination (DDD) system. A dynamic analysis of heat and mass transfer demonstrates that the DDD process can yield a fresh water production of 1.03 million gallon/day by utilizing waste heat from a 100 MW steam power plant based on a condensing steam pressure of only 3 Hg. The optimum operating condition for the DDD process with a high temperature of 50 C and sink temperature of 25 C has an air mass flux of 1.5 kg/m{sup 2}-s, air to feed water mass flow ratio of 1 in the diffusion tower, and a fresh water to air mass flow ratio of 2 in the condenser. Operating at these conditions yields a fresh water production efficiency (m{sub fW}/m{sub L}) of 0.031 and electric energy consumption rate of 0.0023 kW-hr/kg{sub fW}. Throughout the past year, the main focus of the desalination process has been on the direct contact condenser. Detailed heat and mass transfer analyses required to size and analyze these heat and mass transfer devices are described. The analyses agree quite well with the current data. Recently, it has been recognized that the fresh water production efficiency can be significantly enhanced with air heating. This type of configuration is well suited for power plants utilizing air-cooled condensers. The experimental DDD facility has been modified with an air heating section, and temperature and humidity data have been collected over a range of flow and thermal conditions. It has been experimentally observed that the fresh water production rate is enhanced when air

  4. Aplicação de revestimento comestível em abacaxis processados por métodos combinados: isoterma de sorção e cinética de desidratação osmótica Application of edible coatings in processed pineapples products by hurdle technology: desorption isotherms and kinetics of the osmotic dehydration

    Directory of Open Access Journals (Sweden)

    Renata Paula Herrera Brandelero

    2005-06-01

    Full Text Available A desidratação osmótica é uma etapa essencial na elaboração de produtos de fruta através da Tecnologia dos Métodos Combinados ou de Obstáculos ("Hurdle Technology", pois reduz a atividade de água para níveis que, combinando um ou mais obstáculos, aumentam a estabilidade do produto. Neste processo há uma perda de água da fruta para a solução e incorporação de sólidos solúveis pelo produto. Este último fluxo é considerado uma desvantagem do processo pois pode alterar o sabor do produto. Neste trabalho estudou-se a ação de revestimentos comestíveis a base de alginato e gelatina aplicados em abacaxis, previamente à desidratação osmótica, como barreira à incorporação de sólidos solúveis. Os abacaxis com e sem revestimento (controle foram desidratados em solução de sacarose sob condições isotérmicas. Foram determinadas as isotermas de dessorção de abacaxis revestidos com gelatina, alginato e sem revestimento e os parâmetros cinéticos do processo de desidratação osmótica. Abacaxis revestidos com alginato apresentaram menor velocidade de ganho de sólidos, sem alterar a velocidade de perda de água, quando comparado ao controle.The osmotic dehydration is an essential stage to manufacture fruit products by Hurdle Technology because it reduces the water activity to levels that, combined with one or more obstacles, increase the stability of the product. This process causes a loss of water from the fruit to solution and soluble solid incorporation by the product. This last flow is considered a disadvantage of the process because it can modify the product flavor. In this work, the action of alginate and gelatin edible coatings as a barrier to soluble solid incorporation during osmotic dehydration was studied. Pineapples with and without coating (control were dehydrated in sucrose solution under isothermal conditions. The desorption isotherms of pineapples coated with gelatin, sodium alginate and without coating

  5. Equilibrium, hysteresis and kinetics of cadmium desorption from sodium-feldspar using rhamnolipid biosurfactant.

    Science.gov (United States)

    Aşçi, Yeliz; Açikel, Unsal; Açikel, Yeşim Sağ

    2012-09-01

    In this study, the sorption/desorption equilibruim and the desorption kinetics of Cd by rhamnolipid biosurfactant from Na-feldspar as a soil component were investigated. The linear, Langmuir and Freundlich isotherms adequately fitted the equilibrium sorption data with regression coefficients ranging from 0.9836 - 0.9879. However, both the sorption/desorption equilibria were well characterized by the Freundlich model. The extent of hysteresis was quantified based on the differences obtained from sorption and desorption isotherms regarding the quantity of Cd(II) sorbed, the Freundlich exponent, concentration-dependent metal distribution coefficients, and the irreversibility index based on the metal distribution coefficient. The kinetics of desorption of Cd from Na-feldspar was investigated using 77 mM rhamnolipid and at pH 6.8. The first-order, an empirical first-order desorption model (two-coefficient), Lagergren-pseudo-first-order, pseudo-second-order, Elovich and modified Freundlich models were used to describe the kinetic data to estimate the rate constants. To determine the rate-controlling step, the intra-particle diffusion model was also applied to the desorption process. The desorption kinetics of Cd(II) on Na-feldspar was represented better by the pseudo-second-order, Elovich and modified Freundlich equations with correlation coefficients ranging from 0.9941- 0.9982 than by first-order equations. The rate-controlling stage was suggested to be mainly the surface reaction mechanism.

  6. Fate of antibiotics during municipal water recycling treatment processes.

    Science.gov (United States)

    Le-Minh, N; Khan, S J; Drewes, J E; Stuetz, R M

    2010-08-01

    Municipal water recycling processes are potential human and environmental exposure routes for low concentrations of persistent antibiotics. While the implications of such exposure scenarios are unknown, concerns have been raised regarding the possibility that continuous discharge of antibiotics to the environment may facilitate the development or proliferation of resistant strains of bacteria. As potable and non-potable water recycling schemes are continuously developed, it is imperative to improve our understanding of the fate of antibiotics during conventional and advanced wastewater treatment processes leading to high-quality water reclamation. This review collates existing knowledge with the aim of providing new insight to the influence of a wide range of treatment processes to the ultimate fate of antibiotics during conventional and advanced wastewater treatment. Although conventional biological wastewater treatment processes are effective for the removal of some antibiotics, many have been reported to occur at 10-1000 ng L(-1) concentrations in secondary treated effluents. These include beta-lactams, sulfonamides, trimethoprim, macrolides, fluoroquinolones, and tetracyclines. Tertiary and advanced treatment processes may be required to fully manage environmental and human exposure to these contaminants in water recycling schemes. The effectiveness of a range of processes including tertiary media filtration, ozonation, chlorination, UV irradiation, activated carbon adsorption, and NF/RO filtration has been reviewed and, where possible, semi-quantitative estimations of antibiotics removals have been provided. (c) 2010 Elsevier Ltd. All rights reserved.

  7. Technology advancement of the static feed water electrolysis process

    Science.gov (United States)

    Schubert, F. H.; Wynveen, R. A.

    1977-01-01

    A program to advance the technology of oxygen- and hydrogen-generating subsystems based on water electrolysis was studied. Major emphasis was placed on static feed water electrolysis, a concept characterized by low power consumption and high intrinsic reliability. The static feed based oxygen generation subsystem consists basically of three subassemblies: (1) a combined water electrolysis and product gas dehumidifier module; (2) a product gas pressure controller and; (3) a cyclically filled water feed tank. Development activities were completed at the subsystem as well as at the component level. An extensive test program including single cell, subsystem and integrated system testing was completed with the required test support accessories designed, fabricated, and assembled. Mini-product assurance activities were included throughout all phases of program activities. An extensive number of supporting technology studies were conducted to advance the technology base of the static feed water electrolysis process and to resolve problems.

  8. Mercury speciation during in situ thermal desorption in soil

    Energy Technology Data Exchange (ETDEWEB)

    Park, Chang Min, E-mail: cmpark80@gmail.com; Katz, Lynn E.; Liljestrand, Howard M.

    2015-12-30

    Highlights: • Impact of soil conditions on distribution and phase transitions of Hg was identified. • Metallic Hg was slowly transformed to Hg{sup 0} gas until the temperature reached 358.15 K. • Phase change of HgCl{sub 2(s)} completely occurred without decomposition at 335.15 K. • HgS remained solid in dry soil sharply decreased in the narrow temperature range. • Hg gas can be easily captured with higher vapor pressures of soil compositions. - Abstract: Metallic mercury (Hg{sup 0}) and its compounds are highly mobile and toxic environmental pollutants at trace level. In situ thermal desorption (ISTD) is one of the soil remediation processes applying heat and vacuum simultaneously. Knowledge of thermodynamic mercury speciation is imperative to understand the fate and transport of mercury during thermal remediation and operate the treatment processes in a cost-effective manner. Hence, speciation model for inorganic mercury was developed over a range of environmental conditions to identify distribution of dissolved mercury species and potential transformations of mercury at near source environment. Simulation of phase transitions for metallic mercury, mercury(II) chloride and mercury sulfide with temperature increase showed that complete vaporization of metallic mercury and mercury(II) chloride were achieved below the boiling point of water. The effect of soil compositions on mercury removal was also evaluated to better understand thermal remediation process. Higher vapor pressures expected both from soil pore water and inorganic carbonate minerals in soil as well as creation of permeability were significant for complete vaporization and removal of mercury.

  9. INNOVATIVE FRESH WATER PRODUCTION PROCESS FOR FOSSIL FUEL PLANTS

    Energy Technology Data Exchange (ETDEWEB)

    James F. Klausner; Renwei Mei; Yi Li; Mohamed Darwish; Diego Acevedo; Jessica Knight

    2003-09-01

    This report describes the annual progress made in the development and analysis of a Diffusion Driven Desalination (DDD) system, which is powered by the waste heat from low pressure condensing steam in power plants. The desalination is driven by water vapor saturating dry air flowing through a diffusion tower. Liquid water is condensed out of the air/vapor mixture in a direct contact condenser. A thermodynamic analysis demonstrates that the DDD process can yield a fresh water production efficiency of 4.5% based on a feed water inlet temperature of only 50 C. An example is discussed in which the DDD process utilizes waste heat from a 100 MW steam power plant to produce 1.51 million gallons of fresh water per day. The main focus of the initial development of the desalination process has been on the diffusion tower. A detailed mathematical model for the diffusion tower has been described, and its numerical implementation has been used to characterize its performance and provide guidance for design. The analysis has been used to design a laboratory scale diffusion tower, which has been thoroughly instrumented to allow detailed measurements of heat and mass transfer coefficient, as well as fresh water production efficiency. The experimental facility has been described in detail.

  10. THE WATER FROM NATURE AND THE EROSION PROCESS

    Directory of Open Access Journals (Sweden)

    G. PANDI

    2015-03-01

    Full Text Available The water from nature and the erosion process. Studying earth's surface erosion process is necessary for practical reasons. The theoretical approach requires knowledge of the alluvial system’s structure and operation as the cascade sequence of fluvial system’s mass and energy. Geosystem research methodology requires that the water energy and the role of adjacent surface must be expressed. The expression of water power can be grouped according to the shape of movement and action in the basin. A particular, important case is the energy variation in a basin-slope. An important role in energy expressions is considering the existence in nature of biphasic fluid - water as dispersion phase and solid particles as dispersed phase. The role of the adjacent surface is taken into account by using the erosion resistance indicator, which is calculated using the indicator of geological resistance and the indicator of plant protection. The evolution of natural systems, therefore of river basins too, leads to energy diminishing, thus affecting their dynamic balance. This can be expressed using the concept of entropy. Although erosion processes are usual natural phenomena for the evolution of river basins, they induce significant risks in certain circumstances. Depending on the circulated water energies, water basins can be ranked in terms of potential risks.

  11. Note On The Ross Sea Shelf Water Downflow Processes (antarctica)

    Science.gov (United States)

    Bergamasco, A.; Defendi, V.; Spezie, G.; Budillon, G.; Carniel, S.

    In the framework of the CLIMA Project of the Italian National Program for Research in Antarctica, three different experimental data sets were acquired along the continental shelf break; two of them (in 1997 and 2001) close to Cape Adare, the 1998 one in the middle of the Ross Sea (i.e. 75 S, 177 W). The investigations were chosen in order to explore the downslope flow of the bottom waters produced in the Ross Sea, namely the High Salinity Shelf Water (HSSW, the densest water mass of the southern ocean coming from its formation site in the polynya region in Terra Nova bay), and the Ice Shelf Water (ISW, originated below the Ross Ice Shelf and outflowing northward). Both bottom waters spill over the shelf edge and mix with the Circumpolar Deep Water (CDW) contributing to the formation of the Antarctic Bottom Waters (AABW). Interpreting temperature, salinity and density maps in terms of cascading processes, both HSSW and ISW overflows are evidenced during, respectively, 1997 and 1998. During the 2001 acquisition there is no presence of HSSW along the shelf break, nevertheless distribution captures the evidence of a downslope flow process.

  12. The water kefir grain inoculum determines the characteristics of the resulting water kefir fermentation process.

    Science.gov (United States)

    Laureys, D; De Vuyst, L

    2017-03-01

    To investigate the influence of the water kefir grain inoculum on the characteristics of the water kefir fermentation process. Three water kefir fermentation processes were started with different water kefir grain inocula and followed as a function of time regarding microbial species diversity, community dynamics, substrate consumption profile and metabolite production course. The inoculum determined the water kefir grain growth, the viable counts on the grains, the time until total carbohydrate exhaustion, the final metabolite concentrations and the microbial species diversity. There were always 2-10 lactic acid bacterial cells for every yeast cell and the majority of these micro-organisms was always present on the grains. Lactobacillus paracasei, Lactobacillus hilgardii, Lactobacillus nagelii and Saccharomyces cerevisiae were always present and may be the key micro-organisms during water kefir fermentation. Low water kefir grain growth was associated with small grains with high viable counts of micro-organisms, fast fermentation and low pH values, and was not caused by the absence of exopolysaccharide-producing lactic acid bacteria. The water kefir grain inoculum influences the microbial species diversity and characteristics of the fermentation process. A select group of key micro-organisms was always present during fermentation. This study allows a rational selection of a water kefir grain inoculum. © 2016 The Society for Applied Microbiology.

  13. Stage efficiency in the analysis of thermochemical water decomposition processes

    Science.gov (United States)

    Conger, W. L.; Funk, J. E.; Carty, R. H.; Soliman, M. A.; Cox, K. E.

    1976-01-01

    The procedure for analyzing thermochemical water-splitting processes using the figure of merit is expanded to include individual stage efficiencies and loss coefficients. The use of these quantities to establish the thermodynamic insufficiencies of each stage is shown. A number of processes are used to illustrate these concepts and procedures and to demonstrate the facility with which process steps contributing most to the cycle efficiency are found. The procedure allows attention to be directed to those steps of the process where the greatest increase in total cycle efficiency can be obtained.

  14. A soil-column gas chromatography (SCGC) approach to explore the thermal desorption behavior of hydrocarbons from soils.

    Science.gov (United States)

    Yu, Ying; Liu, Liang; Shao, Ziying; Ju, Tianyu; Sun, Bing; Benadda, Belkacem

    2016-01-01

    A soil-column gas chromatography approach was developed to simulate the mass transfer process of hydrocarbons between gas and soil during thermally enhanced soil vapor extraction (T-SVE). Four kinds of hydrocarbons-methylbenzene, n-hexane, n-decane, and n-tetradecane-were flowed by nitrogen gas. The retention factor k' and the tailing factor T f were calculated to reflect the desorption velocities of fast and slow desorption fractions, respectively. The results clearly indicated two different mechanisms on the thermal desorption behaviors of fast and slow desorption fractions. The desorption velocity of fast desorption fraction was an exponential function of the reciprocal of soil absolute temperature and inversely correlated with hydrocarbon's boiling point, whereas the desorption velocity of slow desorption fraction was an inverse proportional function of soil absolute temperature, and inversely proportional to the log K OW value of the hydrocarbons. The higher activation energy of adsorption was found on loamy soil with higher organic content. The increase of carrier gas flow rate led to a reduction in the apparent activation energy of adsorption of slow desorption fraction, and thus desorption efficiency was significantly enhanced. The obtained results are of practical interest for the design of high-efficiency T-SVE system and may be used to predict the remediation time.

  15. Modeling the water decarbonization processes in atmospheric deaerators

    Science.gov (United States)

    Leduhovsky, G. V.

    2017-02-01

    A mathematical model of the water decarbonization processes in atmospheric deaerators is proposed to calculate the thermal decomposition degree of hydrocarbonates in a deaerator, pH of a deaerated water sample, and the mass concentration of free carbonic acid in it on a carbon dioxide basis. The mathematical description of these processes is based on the deaeration tank water flow model implemented in the specialized software suite for the calculation of three-dimensional liquid flows, where a real water flow is a set of parallel small plug-flow reactors, and the rate constant of the reaction representing a generalized model of the thermal decomposition of hydrocarbonates with consideration for its chemical and diffusion stages is identified by experimental data. Based on the results of experimental studies performed on deaerators of different designs with and without steam bubbling in their tanks, an empirical support of this model has been developed in the form of recommended reaction order and rate constant values selected depending on the overall alkalinity of water fed into a deaerator. A self-contained mathematical description of the water decarbonization processes in deaerators has been obtained. The proposed model precision has been proven to agree with the specified metrological characteristics of the potentiometric and alkalimetric methods for measuring pH and the free carbonic acid concentration in water. This allows us to recommend the obtained model for the solution of practical problems of forming a specified amount of deaerated water via the selection of the structural and regime parameters of deaerators during their design and regime adjustment.

  16. Predicting the residual aluminum level in water treatment process

    Directory of Open Access Journals (Sweden)

    J. Tomperi

    2013-06-01

    Full Text Available In water treatment processes, aluminum salts are widely used as coagulation chemical. High dose of aluminum has been proved to be at least a minor health risk and some evidence points out that aluminum could increase the risk of Alzheimer's disease. Thus it is important to minimize the amount of residual aluminum in drinking water and water used at food industry. In this study, the data of a water treatment plant (WTP was analyzed and the residual aluminum in drinking water was predicted using Multiple Linear Regression (MLR and Artificial Neural Network (ANN models. The purpose was to find out which variables affect the amount of residual aluminum and create simple and reliable prediction models which can be used in an early warning system (EWS. Accuracy of ANN and MLR models were compared. The new nonlinear scaling method based on generalized norms and skewness was used to scale all measurement variables to range [−2...+2] before data-analysis and modeling. The effect of data pre-processing was studied by comparing prediction results to ones achieved in an earlier study. Results showed that it is possible to predict the baseline level of residual aluminum in drinking water with a simple model. Variables that affected the most the amount of residual aluminum were among others: raw water temperature, raw water KMnO4 and PAC/KMnO4 (Poly-Aluminum Chloride/Potassium permanganate-ratio. The accuracies of MLR and ANN models were found to be almost the same. Study also showed that data pre-processing affects to the final prediction result.

  17. In situ trace detection of peroxide explosives by desorption electrospray ionization and desorption atmospheric pressure chemical ionization.

    Science.gov (United States)

    Cotte-Rodríguez, Ismael; Hernandez-Soto, Heriberto; Chen, Hao; Cooks, R Graham

    2008-03-01

    Desorption electrospray ionization (DESI) mass spectrometry is used for the rapid (process triggered by an unusual homolytic cleavage of the peroxide bond, forming a distonic ion. This is followed by elimination of a fragment of 30 mass units, shown to be the expected neutral molecule, formaldehyde, in the case of HMTD, but shown by isotopic labeling experiments to be ethane in the cases of TATP and TrATrP. Density functional theory (DFT) calculations support the suggested fragmentation mechanisms for the complexes. Binding energies of Na+ of 40.2 and 33.1 kcal/mol were calculated for TATP-Na(+) and HMTD-Na(+) complexes, suggesting a strong interaction between the peroxide groups and the sodium ion. Increased selectivity is obtained either by MS/MS or by doping the spray solvent with additives that produce the lithium and potassium complexes of TATP, HMTD, and TrATrP. Addition of dopants into the solvent spray increased the signal intensity by an order of magnitude. When pure alcohol or aqueous hydrogen peroxide was used as the spray solvent, the (HMTD + Na)+ complex was able to bind a molecule of alcohol (methanol or ethanol) or hydrogen peroxide, providing additional characteristic ions to increase the selectivity of analysis. DESI also allowed the rapid detection of peroxide explosives in complex matrixes such as diesel fuel and lubricants using single or multiple cation additives (Na(+), K(+), and Li(+), and NH4(+)) in the spray solvent. Low-nanogram detection limits were achieved for HMTD, TrATrP, and TATP in these complex matrixes. The DESI response was linear over 3 orders of magnitude for HMTD and TATP on paper surfaces (1-5000 ng), and quantification of both peroxide explosives from paper gave precisions (RSD) of less than 3%. The use of pure water and compressed air as the DESI spray solution and nebulizing gas, respectively, showed similar ionization efficiencies to those obtained using methanol/water mixtures and nitrogen gas (the typical choices). An

  18. Desorption of Pb 2+ and Cu 2+ from Nipa palm ( Nypa fruticans ...

    African Journals Online (AJOL)

    The data shows that desorption in all the reagent increased with increase in contact time, reaching 75.3 and 63.7% in acid reagent, 18.9 and 14.06% in basic reagent and 3.35 and 2.44% in distilled water for Pb2+ and Cu2+, respectively, at a contact time of 140 min. The desorption kinetic showed that the release constant, ...

  19. Spiral Surface Growth without Desorption

    Energy Technology Data Exchange (ETDEWEB)

    Karma, A.; Plapp, M. [Department of Physics and Center for Interdisciplinary Research on Complex Systems, Northeastern University, Boston, Massachusetts 02115 (United States)

    1998-11-01

    Spiral surface growth is well understood in the limit where the step motion is controlled by the local supersaturation of adatoms near the spiral ridge. In epitaxial thin-film growth, however, spirals can form in a step-flow regime where desorption of adatoms is negligible and the ridge dynamics is governed by the nonlocal diffusion field of adatoms on the whole surface. We investigate this limit numerically using a phase-field formulation of the Burton-Cabrera-Frank model, as well as analytically. Quantitative predictions, which differ strikingly from those of the local limit, are made for the selected step spacing as a function of the deposition flux, as well as for the dependence of the relaxation time to steady-state growth on the screw dislocation density. {copyright} {ital 1998} {ital The American Physical Society }

  20. Remediation approach for organic compounds and arsenic co-contaminated soil using the pressurized hot water extraction process.

    Science.gov (United States)

    Islam, Mohammad Nazrul; Jo, Young-Tae; Jeong, Yeon-Jae; Park, Jeong-Hun

    2017-09-26

    Successful remediation of soil with co-existing organics contaminants and arsenic (As) is a challenge as the chemical and remediation technologies are different for each group of pollutants. In this study, the treatment effectiveness of the pressurized hot water (PHW) extraction process was investigated for remediation of soil co-contaminated with phenol, crude oil, polycyclic aromatic hydrocarbons (PAHs), and As. An elimination percentage of about 99% was achieved for phenol, and in the range of 63-100% was observed for the PAHs at 260°C for 90 min operation. The performance of PHW extraction in the removal of total petroleum hydrocarbons was found to be 86%. Of the 87 mg/kg of As in untreated soil, 67% of which was eliminated after treatment. The removal of organic contaminants was mainly via desorption, dissolution and degradation in subcritical water, while As was eliminated probably by oxidation and dissolution of arsenic-bearing minerals. According to the experimental results, the PHW extraction process can be suggested as an alternative cleaning technology, instead of using any organic solvents for remediation of such co-contaminated soil.

  1. Integration of drinking water treatment plant process models and emulated process automation software

    OpenAIRE

    Worm, G.I.M.

    2012-01-01

    The objective of this research is to limit the risks of fully automated operation of drinking water treatment plants and to improve their operation by using an integrated system of process models and emulated process automation software. This thesis contains the design of such an integrated system. The use of the system is investigated in the three identified applications, i) optimization of process control, ii) training of operation supervisors and iii) virtual commissioning of process autom...

  2. New process for screen cutting: water-jet guided laser

    Science.gov (United States)

    Perrottet, Delphine; Amorosi, Simone; Richerzhagen, Bernold

    2005-07-01

    Today's OLED manufacturers need high-precision, fast tools to cut the metal screens used to deposit the electroluminescent layers onto the substrate. Conventional methods -tching and dry laser cutting - are not satisfying regarding the demands of high-definition OLED displays. A new micro machining technology, the water jet guided laser - a hybrid of laser and water jet technologies that has been actively used in recent years in the electronic and semiconductor field - is now available to OLED manufacturers. This technology represents a significant improvement in screen, mask and stencil cutting, as it combines high precision and high speed. It is able to cut small apertures with totally clean edges (no dross or slag), as the water jet removes the particles and a thin water film is maintained on the material surface during the process. Because the water jet cools the material between the laser pulses, the cut material is free of any thermal stress. The water jet guided laser is also a very fast process: as an example, rectangular slots can be cut in 30 to 50 microns thick stainless steel or nickel at a rate between 25'000 and 30'000 holes per hour.

  3. Leader completes installation of process water evaporation system

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    2005-11-01

    The installation of a patent-pending evaporation system at a facility in northeast British Columbia was discussed. The system captures excess waste exhaust heat from natural gas-fired compressor engines and is used to evaporate process water. The disposal of process water is a major cost in the production of natural gas and is usually hauled and disposed at water disposal wells located off-site. The cost to truck and dispose of the water at the facility was estimated at between $30 to $40 per cubic metre. The evaporation system can evaporate 4 to 8 cubic metres of process water every 24 hours and has an estimated useful life of 20 years. The evaporator relies on heat that would otherwise be expelled directly into the atmosphere, and the systems are expected to provide substantial savings. A wide-ranging manufacturing and marketing strategy was expected to commence by the end of 2005. With rising energy prices, operators of facilities are seeking more efficient ways of managing energy needs. The system was created by Leader Energy Services Ltd., a company that provides essential field services for oil and gas well stimulation in Alberta.

  4. An Excel Workbook for Identifying Redox Processes in Ground Water

    Science.gov (United States)

    Jurgens, Bryant C.; McMahon, Peter B.; Chapelle, Francis H.; Eberts, Sandra M.

    2009-01-01

    The reduction/oxidation (redox) condition of ground water affects the concentration, transport, and fate of many anthropogenic and natural contaminants. The redox state of a ground-water sample is defined by the dominant type of reduction/oxidation reaction, or redox process, occurring in the sample, as inferred from water-quality data. However, because of the difficulty in defining and applying a systematic redox framework to samples from diverse hydrogeologic settings, many regional water-quality investigations do not attempt to determine the predominant redox process in ground water. Recently, McMahon and Chapelle (2008) devised a redox framework that was applied to a large number of samples from 15 principal aquifer systems in the United States to examine the effect of redox processes on water quality. This framework was expanded by Chapelle and others (in press) to use measured sulfide data to differentiate between iron(III)- and sulfate-reducing conditions. These investigations showed that a systematic approach to characterize redox conditions in ground water could be applied to datasets from diverse hydrogeologic settings using water-quality data routinely collected in regional water-quality investigations. This report describes the Microsoft Excel workbook, RedoxAssignment_McMahon&Chapelle.xls, that assigns the predominant redox process to samples using the framework created by McMahon and Chapelle (2008) and expanded by Chapelle and others (in press). Assignment of redox conditions is based on concentrations of dissolved oxygen (O2), nitrate (NO3-), manganese (Mn2+), iron (Fe2+), sulfate (SO42-), and sulfide (sum of dihydrogen sulfide [aqueous H2S], hydrogen sulfide [HS-], and sulfide [S2-]). The logical arguments for assigning the predominant redox process to each sample are performed by a program written in Microsoft Visual Basic for Applications (VBA). The program is called from buttons on the main worksheet. The number of samples that can be analyzed

  5. The effects of the biogeochemical properties of clay minerals on the Pb sorption and desorption in various redox condition

    Science.gov (United States)

    Koo, T. H.; Kim, J. Y.; Kim, J. W.

    2016-12-01

    The fate and transportation of hazardous trace metal in soil environment can be controlled by various factors including temperature, geological location, properties of bed rock or sediment, human behavior, and biogeochemical reactions. The sorption and desorption process is one of the major process for control the transportation of trace metal in soil-water system. Nonetheless, few studies were focused on the biological controlling parameters, particularly redox reaction of structural metal of clay minerals. Thus, the objective of the present study is to investigate the correlation between the sorption and desorption reaction of Pb and biogeochemical properties of clay minerals. The effects of redox state of structural Fe and layer charge of the minerals on the migration/speciation of Pb at the various geochemical environment will be elucidated. The Fe-rich smectite, nontronite (NAu-1), and bulk soil samples which were collected from abandoned mine areas were reduced by microbial respiration by Shewanella Oneidensis MR-1 and/or Na-dithionite to various oxidation state of structural Fe. Then the Pb-stock solution made with common lead and nitric acid were spiked into the mineral/soil slurry with various Pb concentration to test the sorption and desorption reaction upto 7 days. The reaction was stopped at each time point by freezing the pellet and supernatant separately after centrifugation. Then the concentration and stable isotope ratio of Pb in the supernatant were measured using Inductively Coupled Plasma Mass Spectrometer (ICP-MS) and Multicollector (MC)-ICP-MS. The structural as well as chemical modification on nontronite and bulk soil sample were measured using x-ray diffraction (XRD), scanning electron microscopy (SEM) and wet chemistry analysis. The changes in Pb species in supernatant by sorption and desorption and its consequences on the clay structural/biogeochemical properties will be discussed.

  6. Design and development of sustainable remediation process for mitigation of fluoride contamination in ground water and field application for domestic use.

    Science.gov (United States)

    Gwala, Poonam; Andey, Subhash; Nagarnaik, Pranav; Ghosh, Sarika Pimpalkar; Pal, Prashant; Deshmukh, Prashant; Labhasetwar, Pawan

    2014-08-01

    Decentralised household chemo defluoridation unit (CDU) was developed and designed based on a combination of coagulation and sorption processes. Chemo-defluoridation process was optimised to reduce use of chemicals and increase acceptability among beneficiaries without affecting palatability of water. Chemical dose optimization undertaken in the laboratory using jar test revealed the optimum calcium salt to initial fluoride ratio of 60 for fluoride removal. Performance of CDU was evaluated in the laboratory for removal efficiency, water quality parameters, filter bed cleaning cycle and desorption of fluoride. CDU evaluation in the laboratory with spiked water (5 mg/L) and field water (~4.2 mg/L) revealed treated water fluoride concentration of less than 1mg/L. Seventy five CDUs were installed in households at Sakhara Village, Yavatmal District in Maharashtra State of India. Monthly monitoring of CDUs for one year indicated reduction of the raw water fluoride concentration from around 4 mg/L to less than 1mg/L. Post implementation survey after regular consumption of treated drinking water by the users for one year indicated user satisfaction and technological sustainability. Copyright © 2014 Elsevier B.V. All rights reserved.

  7. Toxicity Evaluation and Cytogenetic Screening of Process Water ...

    African Journals Online (AJOL)

    The effect of toxic substances on aquatic lives from a wastewater indiscriminately discharged into the environment during oil and gas exploration activities in Nigeria is the focus of this study. A plant bioassay, the Allium cepa test, was used for the cytogenotoxicity screening of process water on root growth inhibition and ...

  8. COST ESTIMATION MODELS FOR DRINKING WATER TREATMENT UNIT PROCESSES

    Science.gov (United States)

    Cost models for unit processes typically utilized in a conventional water treatment plant and in package treatment plant technology are compiled in this paper. The cost curves are represented as a function of specified design parameters and are categorized into four major catego...

  9. [Effects of quantum nonlocality in the water activation process].

    Science.gov (United States)

    Zatsepina, O V; Stekhin, A A; Yakovleva, G V

    2014-01-01

    The dynamic alterations of the magnetic flux density of the water volume, activated with structurally stressed calcium carbonate in micellar form have been investigated. The phase of the associated water was established to exhibit electrical and magnetic properties, recorded by in B&E meter in the frequency range of 5Hz - 2kHz. Alterations in water Eh (redox) potential and the magnetic flux density B testify to synchronous auto-oscillatory changes. This gives evidence of non-linearity of the relationship between auto-oscillatory processes excited in the water; and reflects the nonlocal in time the relationship between the states of water, manifesting in a change of water activity on the 1st and 2nd day in negative time. The mechanism of action of associated water phase is shown to be described by de Broglie concept of matter waves with taking into account delocalized in time states of phase of electron wave packet in accordance with the transactional interpretation of quantum physics.

  10. Sodium dichromate as a process water additive: An evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Lutton, J.M.

    1953-03-19

    For several years-after the start-up of the Hanford Piles, little concern was felt for the quality of process water. Techniques developed by CMX and improved in the course of operating experience were substantially successful for controlling and removing pressure drop film; and corru%ion rates at the early power levels were uniformly low and not a matter of concern, particularly since slugs were not exposed for more than 250 MWD/ton. As power and exposure levels were drastically increased, however, corrosion rates began to become serious and now threaten to limit future increases. Whether or not corrosion was causing these latter problems, it was clearly imperative to seek ways to reduce the corrobivity of the water. It was recognized that subtantial savings could be made by the elimination of sodium dichromate as a process water additive. Since the rather high pH of process water was neceasary primarily to prevent dichromate reduction, the way would then be open for reducing the pH, and it was hoped that this would improve in-pile corrosion and materially reduce water treatment costs. There is a large amount of data in the project literature pertaining to the dichromate problem, and it seemed urgent in view of recent experiences to re-evaluate this information to learn whether the issues might not be clarified and firm conclusions reached. This document presents such a re-evaluation and drawn conclusions which pending the completion of experiments now in progress, will serve as a primary basis for technical recommendations concerning dichromate addition to process water at all existing 100 areas and at the 100-K areas now under construction.

  11. Multiphase simulation of mine waters and aqueous leaching processes

    Directory of Open Access Journals (Sweden)

    Pajarre Risto

    2016-01-01

    Full Text Available Managing of large amounts of water in mining and mineral processing sites remains a concern in both actively operated and closed mining areas. When the mining site with its metal or concentrate producing units is operational, the challenge is to find either ways for economical processing with maximum yields, while minimizing the environmental impact of the water usage and waste salt treatments. For safe closure of the site, the environmental control of possible drainage will be needed. For both challenges, the present-day multiphase process simulations tools can be used to provide improved accuracy and better economy in controlling the smooth and environmentally sound operation of the plant. One of the pioneering studies in using the multiphase thermodynamic software in simulation of hydrometallurgical processes was that of Koukkari et al. [1]. The study covered the use of Solgasmix equilibrium software for a number of practical acid digesters. The models were made for sulfuric acid treatments in titania pigment production and in NPK fertilizer manufacturing. During the past two decades the extensive data assessment has taken place particularly in geochemistry and a new versions of geochemical multiphase equilibrium software has been developed. On the other hand, there has been some progress in development of the process simulation software in all the aforementioned fields. Thus, the thermodynamic simulation has become a tool of great importance in development of hydrometallurgical processes. The presentation will cover three example cases of either true pilot or industrial systems including a South African acid mine water drainage treatment, hydrometallurgical extraction of rare earths from uranium leachate in Russia and a multistage process simulation of a Finnish heap leaching mine with its subsequent water treatment system.

  12. INNOVATIVE FRESH WATER PRODUCTION PROCESS FOR FOSSIL FUEL PLANTS

    Energy Technology Data Exchange (ETDEWEB)

    James F. Klausner; Renwei Mei; Yi Li; Jessica Knight

    2004-09-01

    An innovative Diffusion Driven Desalination (DDD) process was recently described where evaporation of mineralized water is driven by diffusion within a packed bed. The energy source to drive the process is derived from low pressure condensing steam within the main condenser of a steam power generating plant. Since waste heat is used to drive the process, the main cost of fresh water production is attributed to the energy cost of pumping air and water through the packed bed. This report describes the annual progress made in the development and analysis of a Diffusion Driven Desalination (DDD) system. A combined thermodynamic and dynamic analysis demonstrates that the DDD process can yield a fresh water production of 1.03 million gallon/day by utilizing waste heat from a 100 MW steam power plant based on a condensing steam pressure of only 3'' Hg. Throughout the past year, the main focus of the desalination process has been on the diffusion tower and direct contact condenser. Detailed heat and mass transfer analyses required to size and analyze these heat and mass transfer devices are described. An experimental DDD facility has been fabricated, and temperature and humidity data have been collected over a range of flow and thermal conditions. The analyses agree quite well with the current data and the information available in the literature. Direct contact condensers with and without packing have been investigated. It has been experimentally observed that the fresh water production rate is significantly enhanced when packing is added to the direct contact condensers.

  13. Desorption of plutonium from montmorillonite: An experimental and modeling study

    Science.gov (United States)

    Begg, James D.; Zavarin, Mavrik; Kersting, Annie B.

    2017-01-01

    Desorption of plutonium (Pu) will likely control the extent to which it is transported by mineral colloids. We evaluated the adsorption/desorption behavior of Pu on SWy-1 montmorillonite colloids at pH 4, pH 6, and pH 8 using batch adsorption and flow cell desorption experiments. After 21 days adsorption, Pu(IV) affinity for montmorillonite displayed a pH dependency, with Kd values highest at pH 4 and lowest at pH 8. The pH 8 experiment was further allowed to equilibrate for 6 months and showed an increase in Kd, indicating that true sorption equilibrium was not achieved within the first 21 days. For the desorption experiments, aliquots of the sorption suspensions were placed in a flow cell, and Pu-free solutions were then pumped through the cell for a period of 12 days. Changes in influent solution flow rate were used to investigate the kinetics of Pu desorption and demonstrated that it was rate-limited over the experimental timescales. At the end of the 12-day flow cell experiments, the extent of desorption was again pH dependent, with pH 8 > pH 6 > pH 4. Further, at pH 8, less Pu was desorbed after an adsorption contact time of 6 months than after a contact time of 21 days, consistent with an aging of Pu on the clay surface. A conceptual model for Pu adsorption/desorption that incorporated known surface-mediated Pu redox reactions was used to fit the experimental data. The resulting rate constants indicated processes occurring on timescales of months and even years which may, in part, explain observations of clay colloid-facilitated Pu transport on decadal timescales. Importantly, however, our results also imply that migration of Pu adsorbed to montmorillonite colloids at long (50-100 year) timescales under oxic conditions may not be possible without considering additional phenomena, such as co-precipitation.

  14. Integration of drinking water treatment plant process models and emulated process automation software

    NARCIS (Netherlands)

    Worm, G.I.M.

    2012-01-01

    The objective of this research is to limit the risks of fully automated operation of drinking water treatment plants and to improve their operation by using an integrated system of process models and emulated process automation software. This thesis contains the design of such an integrated system.

  15. Continuous cadmium removal from aqueous solutions by seaweed in a packed-bed column under consecutive sorption-desorption cycles

    Energy Technology Data Exchange (ETDEWEB)

    Jafari, Seyed Ali; Jamali, Abbas [Persian Gulf Research Institute, Persian Gulf University, 75169, Bushehr (Iran, Islamic Republic of)

    2016-04-15

    Packed-bed column process efficiency for cadmium adsorption from aqueous solution was investigated under different bed heights (2.6 to 7.5 cm) and feed flow rates (15 to 30 ml min{sup -1}). The column was filled with brown seaweed, Sargassum angustifolium. Three simplified models, including Bed Depth Service Time, Thomas, and Yoon- Nelson were employed for describing the experimental breakthrough curves as well as achieving design parameters. Bed lifetime was also evaluated in several consecutive sorption-desorption cycles. Cadmium concentration of 0.005mg l−1, as a standard limit for potable water, was considered as the breakthrough concentration. The maximum column performance was achieved 81% at 7.5 cm bed length and flow rate of 15 ml min{sup -1}. Indeed, increasing the bed height increased the sorption performance and service time, while increasing the feed flow rate had a negative effect. Maximum sorption capacity value remained almost constant by the bed height changes; however, increase in the feed flow rate slightly decreased it. The modeling results revealed that the Yoon-Nelson model was more accurate than Thomas for describing the experimental breakthrough data, especially at low flow rates. Column service time predictions were surprisingly achieved using the Bed Depth Service Time model even at extrapolations. 20% reduction in column adsorption efficiency was observed at the end of four consecutive sorption-desorption cycles; however, desorption efficiencies were achieved more than 99% in each cycle.

  16. Microbial fuel cell treatment of ethanol fermentation process water

    Science.gov (United States)

    Borole, Abhijeet P [Knoxville, TN

    2012-06-05

    The present invention relates to a method for removing inhibitor compounds from a cellulosic biomass-to-ethanol process which includes a pretreatment step of raw cellulosic biomass material and the production of fermentation process water after production and removal of ethanol from a fermentation step, the method comprising contacting said fermentation process water with an anode of a microbial fuel cell, said anode containing microbes thereon which oxidatively degrade one or more of said inhibitor compounds while producing electrical energy or hydrogen from said oxidative degradation, and wherein said anode is in electrical communication with a cathode, and a porous material (such as a porous or cation-permeable membrane) separates said anode and cathode.

  17. Nonisothermal Desorption of the Libr Aqueous Salt Solution in Minichannels

    Directory of Open Access Journals (Sweden)

    Misyura S.Y.

    2015-01-01

    Full Text Available This work is devoted the research for two (three-phase flows of LiBr water solution in minichannels with different heat flux and wall thicknesses. Six flow patterns have been observed: a bubble flow, plug flow, laminar and oscillating laminar flow, mist flow, and flow locking. The physical solution properties and the equilibrium conditions change in time. The desorption rate depends not only on the heat flow and speed ratio of vapor to liquid, but also on the total area of the interface (liquid-vapor. The third phase (solid crystal hydrates are formed under high heat fluxes and in the presence of boiling crisis. A variation in the wall thickness leads to a change in the desorption mode. With increasing wall thickness the boiling crisis is realized at higher heat fluxes.

  18. Carbon cycle. Sunlight controls water column processing of carbon in arctic fresh waters.

    Science.gov (United States)

    Cory, Rose M; Ward, Collin P; Crump, Byron C; Kling, George W

    2014-08-22

    Carbon in thawing permafrost soils may have global impacts on climate change; however, the factors that control its processing and fate are poorly understood. The dominant fate of dissolved organic carbon (DOC) released from soils to inland waters is either complete oxidation to CO2 or partial oxidation and river export to oceans. Although both processes are most often attributed to bacterial respiration, we found that photochemical oxidation exceeds rates of respiration and accounts for 70 to 95% of total DOC processed in the water column of arctic lakes and rivers. At the basin scale, photochemical processing of DOC is about one-third of the total CO2 released from surface waters and is thus an important component of the arctic carbon budget. Copyright © 2014, American Association for the Advancement of Science.

  19. First-principles calculations of helium and neon desorption from cavities in silicon.

    Science.gov (United States)

    Eddin, A Charaf; Pizzagalli, L

    2012-05-02

    Combining density functional theory, the nudged elastic band technique, and the ultradense fluid model, we investigated the desorption process of He and Ne in silicon. Our results show that the internal surfaces of gas-filled bubbles are not a limiting factor during desorption experiments, since the surface reconstruction opens diffusion paths easier than in the bulk. We show that the vibrational contribution to the energy of helium in the bulk has to be considered in order to determine realistic pressures in the bubbles, when comparing experiments and simulations. At the maximum of desorption, an average pressure of 1-2 GPa is computed. © 2012 IOP Publishing Ltd

  20. COCONUT WATER VINEGAR: NEW ALTERNATIVE WITH IMPROVED PROCESSING TECHNIQUE

    Directory of Open Access Journals (Sweden)

    MUHAMMAD ANAS OTHAMAN

    2014-06-01

    Full Text Available Vinegar is a condiment made from various sugary and starchy materials by alcoholic and subsequent acetic fermentation. Vinegar can be produced via different methods and from various types of raw material. A new alternative substrate for vinegar production namely mature coconut water has been tested and was compared with 2 common substrates which were coconut sap and pineapple juice. Substrates such as sap and juices have been found to have high amount of total soluble solids which corresponding to high sugar content in the substrates which is more than 14oBrix. Therefore, both substrates could be directly used for vinegar production without requirement of other carbon sources. However, coconut water which showed low Brix value need to be adjusted to 14oBrix by adding sucrose prior to the fermentation process. Substrates fermented with Saccharomyces cerevisiae have yielded 7-8% of alcohol within 7-10 days aerobic incubation at room temperature. The alcoholic medium were then used as a seed broth for acetic fermentation with Acetobactor aceti as inoculums and fermented for approximately 2 months to obtain at least 4% of acetic acid. Investigation on the effect of inoculum sizes and implementation of back-slopping technique were performed to improve the processing method for coconut water vinegar production. The results show that 10% of inoculum size was the best for acetic acid fermentation and the back-slopping technique has helped to reduce the process time of coconut water vinegar production.

  1. Radiation processing applications in the Czechoslovak water treatment technologies

    Science.gov (United States)

    Vacek, K.; Pastuszek, F.; Sedláček, M.

    The regeneration of biologically clogged water wells by radiation proved to be a successful and economically beneficial process among other promising applications of ionizing radiation in the water supply technology. The application conditions and experience are mentioned. The potential pathogenic Mycobacteria occuring in the warm washing and bathing water are resistant against usual chlorine and ozone concentrations. The radiation sensitivity of Mycobacteria allowed to suggest a device for their destroying by radiation. Some toxic substances in the underground water can be efficiently degraded by gamma radiation directly in the wells drilled as a hydraulic barrier surrounding the contaminated land area. Substantial decrease of CN - concentration and C.O.D. value was observed in water pumped from such well equipped with cobalt sources and charcoal. The removing of pathogenic contamination remains to be the main goal of radiation processing in the water purification technologies. The decrease of liquid sludge specific filter resistance and sedimentation acceleration by irradiation have a minor technological importance. The hygienization of sludge cake from the mechanical belt filter press by electron beam appears to be the optimum application in the Czechoslovak conditions. The potatoes and barley crop yields from experimental plots treated with sludge were higher in comparison with using the manure. Biological sludge from the municipal and food industry water purification plants contains nutritive components. The proper hygienization is a necessary condition for using them as a livestock feed supplement. Feeding experiments with broilers and pigs confirmed the possibility of partial (e.g. 50%) replacement of soya-, bone- or fish flour in feed mixtures by dried sludge hygienized either by heat or by the irradiation.

  2. Water treatment process in the JEN-1 Research Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Urgel, M.; Perez-Bustamante, J. A.; Batuecas, T.

    1965-07-01

    The main characteristics and requirements which must be met with by waters to be used for nuclear reactors were studied paying attention separately both to those used in primary and secondary circuits as well as to the purification systems to be employed in each case. The experiments carried out for the initial pretreatment of water and the ion-exchange de ionization processes including a number of systems consisting of separated and mixed beds loaded with a variety of different commercially available resins are described. (Author) 24 refs.

  3. Hydrological balance and water transport processes of partially sealed soils

    Science.gov (United States)

    Timm, Anne; Wessolek, Gerd

    2017-04-01

    With increased urbanisation, soil sealing and its drastic effects on hydrological processes have received a lot of attention. Based on safety concerns, there has been a clear focus on urban drainage and prevention of urban floods caused by storm water events. For this reason, any kind of sealing is often seen as impermeable runoff generator that prevents infiltration and evaporation. While many hydrological models, especially storm water models, have been developed, there are only a handful of empirical studies actually measuring the hydrological balance of (partially) sealed surfaces. These challenge the general assumption of negligible infiltration and evaporation and show that these processes take place even for severe sealing such as asphalt. Depending on the material, infiltration from partially sealed surfaces can be equal to that of vegetated ones. Therefore, more detailed knowledge is needed to improve our understanding and models. In Berlin, two partially sealed weighable lysimeters were equipped with multiple temperature and soil moisture sensors in order to study their hydrological balance, as well as water and heat transport processes within the soil profile. This combination of methods affirms previous observations and offers new insights into altered hydrological processes of partially sealed surfaces at a small temporal scale. It could be verified that not all precipitation is transformed into runoff. Even for a relatively high sealing degree of concrete slabs with narrow seams, evaporation and infiltration may exceed runoff. Due to the lack of plant roots, the hydrological balance is mostly governed by precipitation events and evaporation generally occurs directly after rainfall. However, both surfaces allow for upward water transport from the upper underlying soil layers, sometimes resulting in relatively low evaporation rates on days without precipitation. The individual response of the surfaces differs considerably, which illustrates how

  4. Contribution to the study of adsorption and desorption of volatile organic compounds on activated carbons; Contribution a l'etude de l'adsorption et de la desorption de composes organiques volatils chlores sur charbons actifs

    Energy Technology Data Exchange (ETDEWEB)

    Cosnier, F.

    2004-11-01

    Adsorption and desorption of water and chlorinated volatile organic compounds (VOCs) in static (adsorption isotherms) and dynamic conditions (breakthrough curves) have been performed on different activated carbons (ACs) (granulated ACs and activated carbons fibers) with different textural characteristics and surface chemistry. The main objective of this study is to separate the different component of a chlorinated VOCs mixture in the presence or not of water vapor. It appears that both porous texture and surface chemistry of ACs as physicochemical characteristics of the probes have a strong influence on their adsorption (or desorption) process (mechanism and kinetics). A special attention has been drawn on the influence of the water presence: at high relative humidity rate, ACs adsorption properties (adsorbed amount and kinetics) for chlorinated VOCs are strongly affected. Separation of the dichloromethane/trichloroethylene mixture has been successfully realized whatever the experimental conditions. Last, an exploratory study on the AC hydrophobisation possibilities by the grafting of non-polar groups in liquid phase has been undertaken in order to limit the water presence effects. (author)

  5. Adsorption and desorption of DNA tuned by hydroxyl groups in graphite oxides-based solid extraction material.

    Science.gov (United States)

    Akceoglu, Garbis Atam; Li, Oi Lun; Saito, Nagahiro

    2015-12-01

    The extraction of DNA is the most crucial method used in molecular biology. Up to date silica matrices has been widely applied as solid support for selective DNA adsorption and extraction. However, since adsorption force of SiOH functional groups is much greater than that of desorption force, the DNA extraction efficiency of silica surfaces is limited. In order to increase the DNA extraction yield, a new surface with different functional groups which possess of greater desorption property is required. In this study, we proposed cellulose/graphite oxide (GO) composite as an alternative material for DNA adsorption and extraction. GO/Cellulose composite provides the major adsorption and desorption of DNA by COH, which belongs to alkyl or phenol type of OH functional group. Compared to SiOH, COH is less polarized and reactive, therefore the composite might provide a higher desorption of DNA during the elution process. The GO/cellulose composite were prepared in spherical structure by mixing urea, cellulose, NaOH, Graphite oxide and water. The concentration of GO within the composites were controlled to be 0-4.15 wt.%. The extraction yield of DNA increased with increasing weight percentage of GO. The highest yield was achieved at 4.15 wt.% GO, where the extraction efficiency was reported as 660.4 ng/μl when applying 2M GuHCl as the binding buffer. The absorbance ratios between 260 nm and 280 nm (A260/A280) of the DNA elution was demonstrated as 1.86, indicating the extracted DNA consisted of high purity. The results proved that GO/cellulose composite provides a simple method for selective DNA extraction with high extraction efficiency of pure DNA. Copyright © 2015 Elsevier B.V. All rights reserved.

  6. Particle dry deposition to water surfaces: Processes and consequences

    DEFF Research Database (Denmark)

    Pryor, S.C.; Barthelmie, R.J.

    2000-01-01

    Algal blooms (increased abundance of phytoplankton) are an increasingly common phenomenon which has been causally linked to increased fluxes of nutrient (particularly nitrogenous) compounds to aquatic ecosystems. These blooms have implications for water quality and human health in addition...... flux to coastal waters, atmosphere-surface exchange represents a significant component of the total flux and may be particularly critical during the summertime when both the riverine input and ambient nutrient concentrations are often at a minimum. In this chapter, we present an overview...... of the physical and chemical processes which dictate the quantity (and direction) of atmosphere-surface fluxes of trace chemicals to (and above) water surfaces with particular emphasis on the role of particles. Dry deposition (transfer to the surface in the absence of precipitation) of particles is determined...

  7. Adsorption-desorption and leaching of pyraclostrobin in Indian soils.

    Science.gov (United States)

    Reddy, S Navakishore; Gupta, Suman; Gajbhiye, Vijay T

    2013-01-01

    desorption, of pyraclostrobin in soils. Higher hysteresis coefficient values in organic carbon removed soil (0.25-0.30) and clay fraction removed soil (0.28-0.36) as compared to normal Inceptisol soil suggest relatively weak adsorption and easy desorption of pyraclostrobin. Results of regression analysis suggest that the organic matter and pH of the soil play a major role in adsorption of pyraclostrobin. Leaching studies were carried out in intact soil columns in Inceptisol. The columns were leached with different amounts of water simulating different amounts of rainfall. The results suggest that most of the pyraclostrobin residues will remain present in the top soil layers even under high rainfall conditions and chances of pyraclostrobin moving to lower soil depth are almost negligible.

  8. Salt Tolerance of Desorption Electrospray Ionization (DESI)

    Energy Technology Data Exchange (ETDEWEB)

    Jackson, Ayanna U. [Purdue University; Talaty, Nari [Purdue University; Cooks, R G [Purdue University; Van Berkel, Gary J [ORNL

    2007-01-01

    Suppression of ion intensity in the presence of high salt matrices is common in most mass spectrometry ionization techniques. Desorption electrospray ionization (DESI) is an ionization method that exhibits salt tolerance, and this is investigated. DESI analysis was performed on three different drug mixtures in the presence of 0, 0.2, 2, 5, 10, and 20% NaCl:KCl weight by volume from seven different surfaces. At physiological concentrations individual drugs in each mixture were observed with each surface. Collision-induced dissociation (CID) was used to provide additional confirmation for select compounds. Multiple stage experiments, to MS5, were performed for select compounds. Even in the absence of added salt, the benzodiazepine containing mixture yielded sodium and potassium adducts of carbamazepine which masked the ions of interest. These adducts were eliminated by adding 0.1% 7M ammonium acetate to the standard methanol:water (1:1) spray solvent. Comparison of the salt tolerance of DESI with that of electrospray ionization (ESI) demonstrated much better signal/noise characteristics for DESI in this study. The salt tolerance of DESI was also studied by performing limit of detection and dynamic range experiments. Even at a salt concentration significantly above physiological concentrations, select surfaces were effective in providing spectra that allowed the ready identification of the compounds of interest. The already high salt tolerance of DESI can be optimized further by appropriate choices of surface and spray solution.

  9. INTEC CPP-603 Basin Water Treatment System Closure: Process Design

    Energy Technology Data Exchange (ETDEWEB)

    Kimmitt, Raymond Rodney; Faultersack, Wendell Gale; Foster, Jonathan Kay; Berry, Stephen Michael

    2002-09-01

    This document describes the engineering activities that have been completed in support of the closure plan for the Idaho Nuclear Technology and Engineering Center (INTEC) CPP-603 Basin Water Treatment System. This effort includes detailed assessments of methods and equipment for performing work in four areas: 1. A cold (nonradioactive) mockup system for testing equipment and procedures for vessel cleanout and vessel demolition. 2. Cleanout of process vessels to meet standards identified in the closure plan. 3. Dismantlement and removal of vessels, should it not be possible to clean them to required standards in the closure plan. 4. Cleanout or removal of pipelines and pumps associated with the CPP-603 basin water treatment system. Cleanout standards for the pipes will be the same as those used for the process vessels.

  10. Effectiveness of Water Desalination by Membrane Distillation Process

    Science.gov (United States)

    Gryta, Marek

    2012-01-01

    The membrane distillation process constitutes one of the possibilities for a new method for water desalination. Four kinds of polypropylene membranes with different diameters of capillaries and pores, as well as wall thicknesses were used in studied. The morphology of the membrane used and the operating parameters significantly influenced process efficiency. It was found that the membranes with lower wall thickness and a larger pore size resulted in the higher yields. Increasing both feed flow rate and temperature increases the permeate flux and simultaneously the process efficiency. However, the use of higher flow rates also enhanced heat losses by conduction, which decreases the thermal efficiency. This efficiency also decreases when the salt concentration in the feed was enhanced. The influence of fouling on the process efficiency was considered. PMID:24958289

  11. Effectiveness of Water Desalination by Membrane Distillation Process

    Directory of Open Access Journals (Sweden)

    Marek Gryta

    2012-07-01

    Full Text Available The membrane distillation process constitutes one of the possibilities for a new method for water desalination. Four kinds of polypropylene membranes with different diameters of capillaries and pores, as well as wall thicknesses were used in studied. The morphology of the membrane used and the operating parameters significantly influenced process efficiency. It was found that the membranes with lower wall thickness and a larger pore size resulted in the higher yields. Increasing both feed flow rate and temperature increases the permeate flux and simultaneously the process efficiency. However, the use of higher flow rates also enhanced heat losses by conduction, which decreases the thermal efficiency. This efficiency also decreases when the salt concentration in the feed was enhanced. The influence of fouling on the process efficiency was considered.

  12. Stripped sour water treatment by advanced oxidation processes

    OpenAIRE

    Guimarães, José R.; Gasparini, Mirthys C.; Maniero,Milena G.; Mendes, Carlos G. N.

    2012-01-01

    This study assessed the application of photolysis (UV), peroxidation (H2O2), peroxidation combined with ultraviolet light (UV/H2O2), Fenton’s reagent (H2O2/Fe(II)) and photo-Fenton (H2O2/Fe(II)/UV) processes in the treatment of stripped sour water from the Petrobras Replan Oil Refinery in Paulínia City, São Paulo State, Brazil. To evaluate the efficiency of the process, the concentration of dissolved organic carbon (DOC) was monitored throughout the reaction period. Among the evaluated proces...

  13. Redox processes and water quality of selected principal aquifer systems

    Science.gov (United States)

    McMahon, P.B.; Chapelle, F.H.

    2008-01-01

    Reduction/oxidation (redox) conditions in 15 principal aquifer (PA) systems of the United States, and their impact on several water quality issues, were assessed from a large data base collected by the National Water-Quality Assessment Program of the USGS. The logic of these assessments was based on the observed ecological succession of electron acceptors such as dissolved oxygen, nitrate, and sulfate and threshold concentrations of these substrates needed to support active microbial metabolism. Similarly, the utilization of solid-phase electron acceptors such as Mn(IV) and Fe(III) is indicated by the production of dissolved manganese and iron. An internally consistent set of threshold concentration criteria was developed and applied to a large data set of 1692 water samples from the PAs to assess ambient redox conditions. The indicated redox conditions then were related to the occurrence of selected natural (arsenic) and anthropogenic (nitrate and volatile organic compounds) contaminants in ground water. For the natural and anthropogenic contaminants assessed in this study, considering redox conditions as defined by this framework of redox indicator species and threshold concentrations explained many water quality trends observed at a regional scale. An important finding of this study was that samples indicating mixed redox processes provide information on redox heterogeneity that is useful for assessing common water quality issues. Given the interpretive power of the redox framework and given that it is relatively inexpensive and easy to measure the chemical parameters included in the framework, those parameters should be included in routine water quality monitoring programs whenever possible.

  14. Water Relationships in the U.S. Southwest: Characterizing Water Management Networks Using Natural Language Processing

    Directory of Open Access Journals (Sweden)

    John T. Murphy

    2014-06-01

    Full Text Available Natural language processing (NLP and named entity recognition (NER techniques are applied to collections of newspaper articles from four cities in the U.S. Southwest. The results are used to generate a network of water management institutions that reflect public perceptions of water management and the structure of water management in these areas. This structure can be highly centralized or fragmented; in the latter case, multiple peer institutions exist that may cooperate or be in conflict. This is reflected in the public discourse of the water consumers in these areas and can, we contend, impact the potential responses of management agencies to challenges of water supply and quality and, in some cases, limit their effectiveness. Flagstaff, AZ, Tucson, AZ, Las Vegas, NV, and the Grand Valley, CO, are examined, including more than 110,000 articles from 2004–2012. Documents are scored by association with water topics, and phrases likely to be institutions are extracted via custom NLP and NER algorithms; those institutions associated with water-related documents are used to form networks via document co-location. The Grand Valley is shown to have a markedly different structure, which we contend reflects the different historical trajectory of its development and its current state, which includes multiple institutions of roughly equal scope and size. These results demonstrate the utility of using NLP and NER methods to understanding the structure and variation of water management systems.

  15. Packaged water: optimizing local processes for sustainable water delivery in developing nations

    Directory of Open Access Journals (Sweden)

    Dada Ayokunle C

    2011-07-01

    Full Text Available Abstract With so much global attention and commitment towards making the Water and Sanitation targets of the Millennium Development Goals (MDGs a reality, available figures seem to speak on the contrary as they reveal a large disparity between the expected and what currently obtains especially in developing countries. As studies have shown that the standard industrialized world model for delivery of safe drinking water technology may not be affordable in much of the developing world, packaged water is suggested as a low cost, readily available alternative water provision that could help bridge the gap. Despite the established roles that this drinking water source plays in developing nations, its importance is however significantly underestimated, and the source considered unimproved going by 'international standards'. Rather than simply disqualifying water from this source, focus should be on identifying means of improvement. The need for intervening global communities and developmental organizations to learn from and build on the local processes that already operate in the developing world is also emphasized. Identifying packaged water case studies of some developing nations, the implication of a tenacious focus on imported policies, standards and regulatory approaches on drinking water access for residents of the developing world is also discussed.

  16. Phosphorus sorption-desorption and effects of temperature, pH and salinity on phosphorus sorption in marsh soils from coastal wetlands with different flooding conditions.

    Science.gov (United States)

    Bai, Junhong; Ye, Xiaofei; Jia, Jia; Zhang, Guangliang; Zhao, Qingqing; Cui, Baoshan; Liu, Xinhui

    2017-12-01

    Wetland soils act as a sink or source of phosphorus (P) to the overlaying water due to phosphorus sorption-desorption processes. Litter information is available on sorption and desorption behaviors of phosphorus in coastal wetlands with different flooding conditions. Laboratory experiments were conducted to investigate phosphorus sorption-desorption processes, fractions of adsorbed phosphorus, and the effects of salinity, pH and temperature on phosphorus sorption on soils in tidal-flooding wetlands (TW), freshwater-flooding wetlands (FW) and seasonal-flooding wetlands (SW) in the Yellow River Delta. Our results showed that the freshly adsorbed phosphorus dominantly exists in Occluded-P and Fe/AlP and their percentages increased with increasing phosphorus adsorbed. Phosphorus sorption isotherms could be better described by the modified Langmuir model than by the modified Freundlich model. A binomial equation could be properly used to describe the effects of salinity, pH, and temperature on phosphorus sorption. Phosphorus sorption generally increased with increasing salinity, pH, and temperature at lower ranges, while decreased in excess of some threshold values. The maximum phosphorus sorption capacity (Qmax) was larger for FW soils (256 mg/kg) compared with TW (218 mg/kg) and SW soils (235 mg/kg) (p water bodies through increasing P sorption. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. New perspectives in vacuum high voltage insulation. II. Gas desorption

    CERN Document Server

    Diamond, W T

    1998-01-01

    An examination has been made of gas desorption from unbaked electrodes of copper, niobium, aluminum, and titanium subjected to high voltage in vacuum. It has been shown that the gas is composed of water vapor, carbon monoxide, and carbon dioxide, the usual components of vacuum outgassing, plus an increased yield of hydrogen and light hydrocarbons. The gas desorption was driven by anode conditioning as the voltage was increased between the electrodes. The gas is often desorbed as microdischarges-pulses of a few to hundreds of microseconds-and less frequently in a more continuous manner without the obvious pulsed structure characteristic of microdischarge activity. The quantity of gas released was equivalent to many monolayers and consisted mostly of neutral molecules with an ionic component of a few percent. A very significant observation was that the gas desorption was more dependent on the total voltage between the electrodes than on the electric field. It was not triggered by field-emitted electrons but oft...

  18. Kinetics of ethylene oxide desorption from sterilized materials.

    Science.gov (United States)

    Mendes, Gisela C; Brandão, Teresa R S; Silva, Cristina L M

    2013-01-01

    Ethylene oxide gas is commonly used to sterilize medical devices, and concerns about using this agent on biological systems are well-established. Medical devices sterilized by ethylene oxide must be properly aerated to remove residual gas and by-products. In this work, kinetics of ethylene oxide desorption from different sterilized materials were studied in a range of aeration temperatures. The experimental data were well-described by a Fickian diffusion mass transfer behavior, and diffusivities were estimated for two textile and two polymeric materials within the temperature range of 1.5 to 59.0 degrees C. The results will allow predictions of ethylene oxide desorption, which is a key step for the design of sterilization/aeration processes, contributing to an efficient removal of residual ethylene oxide content.

  19. Thermal desorption remediation in relation to landfill disposal at isolated sites in northern Alberta

    Energy Technology Data Exchange (ETDEWEB)

    Walker, G.; Henze, M. [ATCO Electric Ltd., Edmonton, AB (Canada); Fernuik, N.; MacKinnon, B. [Thurber Environmental Consultants Ltd., Edmonton, AB (Canada); Nelson, D. [Nelson Environmental Remediation Ltd., Spruce Grove, AB (Canada)

    2005-07-01

    Thermal desorption (TD) involves the application of heat to organic-contaminated soil to release and thermally destruct contaminants using high temperatures. An overview of the technique used in the remediation of diesel-contaminated sites was presented. The paper was divided into 2 parts, the first of which provided an overview of TD at 2 electric company sites with a total of 29,000 tonnes of diesel-contaminated soil. Site contamination occurred mainly through the loading, storage and dispensing of diesel fuel. Petroleum lubricants, polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), glycols and metals were among the other contaminants. Remediation work was comprised of dig and dump (DD) or thermal desorption (TD) treatment of contaminated soils as well as the removal of underground facilities including concrete foundations, screw anchors, storage tanks, pipelines and grounding grids. The TD process, and productivity with both clay and sand soil types was reviewed, and an analysis of direct, indirect and total costs was presented. Issues concerning planning, production rates, practical field experience and quality control procedures were discussed, in addition to limitations such the treatment's inability to remediate metals, sensitivity to soil water content, and water demands for soil processing. The second section described the role of TD in a staged remediation for 46,000 tonnes of diesel-contaminated soil at Fox Lake, a remote northern community accessible by winter road and ice bridges. The challenges of ice bridge construction and maintenance, excavation backfilling and soil transport at low temperature were reviewed. An outline of consultation processes with First Nations was presented, as well as details of site operations and soil hauling, truck restrictions and coordination over the ice bridge, alternate backfill sources, and TD soil treatment of the contaminated soil. 2 tabs.

  20. Sorption and desorption of silver ions by bentonite clays.

    Science.gov (United States)

    Constantino, Leonel Vinicius; Quirino, Juliana Nunes; Monteiro, Alessandra Maffei; Abrão, Taufik; Parreira, Paulo Sérgio; Urbano, Alexandre; Santos, Maria Josefa

    2017-04-01

    Anthropogenic activities have increased the concentration of metal species in the environment. The toxicity of silver ions to aquatic and terrestrial organisms has required monitoring by analytical methods, besides actions to promote its control as pollutant. Sorption and desorption processes are directly related to the mobility and availability of metal ions in the environment. In this context, clay minerals can be used for pre-concentration, removal and recovery of silver ions from aqueous solution. Herein, two bentonite clays (BaVC-1 and SWy-2) were characterised and applied to investigate the sorption and desorption of silver ions. Isotherms were fitted to the dual-mode Langmuir-Freundlich model to qualify and quantify sorption sites and evaluate the mobilisation process. The maximum sorption capacity was 743 and 849 meq kg -1 for BaVC-1 and SWy-2, respectively. Hysteresis index (HI) and mobilisation factor (MF) suggest that the desorption of silver ions in BaVC-1 is about four times more conducive compared to that in SWy-2, although both materials have demonstrated a great potential for Ag + pre-concentration from aqueous solutions.

  1. Methane gas seepage - Disregard of significant water column filter processes?

    Science.gov (United States)

    Schneider von Deimling, Jens; Schmale, Oliver

    2016-04-01

    Marine methane seepage represents a potential contributor for greenhouse gas in the atmosphere and is discussed as a driver for climate change. The ultimate question is how much methane is released from the seafloor on a global scale and what fraction may reach the atmosphere? Dissolved fluxes from methane seepage sites on the seabed were found to be very efficiently reduced by benthic microbial oxidation, whereas transport of free gas bubbles from the seabed is considered to bypass the effective benthic methane filter. Numerical models are available today to predict the fate of such methane gas bubble release to the water column in regard to gas exchange with the ambient water column, respective bubble lifetime and rise height. However, the fate of rising gas bubbles and dissolved methane in the water column is not only governed by dissolution, but is also affected by lateral oceanographic currents and vertical bubble-induced upwelling, microbial oxidation, and physico-chemical processes that remain poorly understood so far. According to this gap of knowledge we present data from two study sites - the anthropogenic North Sea 22/4b Blowout and the natural Coal Oil point seeps - to shed light into two new processes gathered with hydro-acoustic multibeam water column imaging and microbial investigations. The newly discovered processes are hereafter termed Spiral Vortex and Bubble Transport Mechanism. Spiral Vortex describes the evolution of a complex vortical fluid motion of a bubble plume in the wake of an intense gas release site (Blowout, North Sea). It appears very likely that it dramatically changes the dissolution kinetics of the seep gas bubbles. Bubble Transport Mechanism prescribes the transport of sediment-hosted bacteria into the water column via rising gas bubbles. Both processes act as filter mechanisms in regard to vertical transport of seep related methane, but have not been considered before. Spiral Vortex and Bubble Transport Mechanism represent the

  2. Process for purification of waste water produced by a Kraft process pulp and paper mill

    Science.gov (United States)

    Humphrey, M. F. (Inventor)

    1979-01-01

    The water from paper and pulp wastes obtained from a mill using the Kraft process is purified by precipitating lignins and lignin derivatives from the waste stream with quaternary ammonium compounds, removing other impurities by activated carbon produced from the cellulosic components of the water, and then separating the water from the precipitate and solids. The activated carbon also acts as an aid to the separation of the water and solids. If recovery of lignins is also desired, then the precipitate containing the lignins and quaternary ammonium compounds is dissolved in methanol. Upon acidification, the lignin is precipitated from the solution. The methanol and quaternary ammonium compound are recovered for reuse from the remainder.

  3. Effects of Gravity on Supercritical Water Oxidation (SCWO) Processes

    Science.gov (United States)

    Hegde, Uday; Hicks, Michael

    2013-01-01

    The effects of gravity on the fluid mechanics of supercritical water jets are being studied at NASA to develop a better understanding of flow behaviors for purposes of advancing supercritical water oxidation (SCWO) technologies for applications in reduced gravity environments. These studies provide guidance for the development of future SCWO experiments in new experimental platforms that will extend the current operational range of the DECLIC (Device for the Study of Critical Liquids and Crystallization) Facility on board the International Space Station (ISS). The hydrodynamics of supercritical fluid jets is one of the basic unit processes of a SCWO reactor. These hydrodynamics are often complicated by significant changes in the thermo-physical properties that govern flow behavior (e.g., viscosity, thermal conductivity, specific heat, compressibility, etc), particularly when fluids transition from sub-critical to supercritical conditions. Experiments were conducted in a 150 ml reactor cell under constant pressure with water injections at various flow rates. Flow configurations included supercritical jets injected into either sub-critical or supercritical water. Profound gravitational influences were observed, particularly in the transition to turbulence, for the flow conditions under study. These results will be presented and the parameters of the flow that control jet behavior will be examined and discussed.

  4. Aluminium removal from water after defluoridation with the electrocoagulation process.

    Science.gov (United States)

    Sinha, Richa; Mathur, Sanjay; Brighu, Urmila

    2015-01-01

    Fluoride is the most electronegative element and has a strong affinity for aluminium. Owing to this fact, most of the techniques used for fluoride removal utilized aluminium compounds, which results in high concentrations of aluminium in treated water. In the present paper, a new approach is presented to meet the WHO guideline for residual aluminium concentration as 0.2 mg/L. In the present work, the electrocoagulation (EC) process was used for fluoride removal. It was found that aluminium content in water increases with an increase in the energy input. Therefore, experiments were optimized for a minimum energy input to achieve the target value (0.7 mg/L) of fluoride in resultant water. These optimized sets were used for further investigations of aluminium control. The experimental investigations revealed that use of bentonite clay as coagulant in clariflocculation brings down the aluminium concentration of water below the WHO guideline. Bentonite dose of 2 g/L was found to be the best for efficient removal of aluminium.

  5. Carbon dioxide and water adsorption on highly epitaxial Delafossite CuFeO2 thin film

    Science.gov (United States)

    Rojas, S.; Joshi, T.; Borisov, P.; Sarabia, M.; Lederman, D.; Cabrera, A. L.

    2015-03-01

    Thermal programmed desorption (TPD) of CO2 and H2O from a 200 nm thick CuFeO2 Delafossite surface was performed in a standard UHV chamber, The CuFeO2 thin film grown using Pulsed Laser Deposition (PLD) over an Al2O3 (0001) substrate with controlled O2 atmosphere resulted with highly epitaxial crystal structure. The adsorption/desorption of CO2 and H2O process was also monitored with X-ray Photoelectron Spectroscopy (XPS) and Auger Electron Spectroscopy (AES). Our results revealed that carbon dioxide interacts with CuFeO2 forming Fe carbonates compounds on its surface. Hydroxides were also formed on the surface due to water presence. Using TPD data, Arrhenius plots for CO2 and water desorption were done and activation energy for desorption was obtained. Funds FONDECyT 1130372; Thanks to P. Ferrari.

  6. A model for the catalytic reduction of NO with CO and N desorption

    Science.gov (United States)

    Díaz, J. J.; Buendía, G. M.

    2018-02-01

    In this work we have investigated by Monte Carlo simulations the dynamical behavior of a modified Yaldram-Khan (YK) model for the catalytic reduction of NO on a surface. Our model is simulated on a square lattice and includes the individual desorption of CO molecules and N atoms, processes associated with temperature effects. When CO desorption is added, strong fluctuations appear, which are associated with the spreading of N checkerboard structures on the surface. These structures take a long time to coalesce, allowing the existence of a unsteady but long lasting reactive state. N desorption also favors the reactivity of the system, this time by diminishing the size of the N structures and impeding their coalescence. The combined desorption of CO and N produces a reactive state as well, where reactive zones among N structures can take place on the surface.

  7. Impact of activated carbon, biochar and compost on the desorption and mineralization of phenanthrene in soil.

    Science.gov (United States)

    Marchal, Geoffrey; Smith, Kilian E C; Rein, Arno; Winding, Anne; Wollensen de Jonge, Lis; Trapp, Stefan; Karlson, Ulrich G

    2013-10-01

    Sorption of PAHs to carbonaceous soil amendments reduces their dissolved concentrations, limiting toxicity but also potentially biodegradation. Therefore, the maximum abiotic desorption of freshly sorbed phenanthrene (≤5 mg kg(-1)) was measured in three soils amended with activated carbon (AC), biochar or compost. Total amounts of phenanthrene desorbed were similar between the different soils, but the amendment type had a large influence. Complete desorption was observed in the unamended and compost amended soils, but this reduced for biochar (41% desorbed) and AC (8% desorbed). Cumulative amounts mineralized were 28% for the unamended control, 19% for compost, 13% for biochar and 4% for AC. Therefore, the effects of the amendments in soil in reducing desorption were also reflected in the extents of mineralization. Modeling was used to analyze key processes, indicating that for the AC and charcoal treatments bacterial activity did not limit mineralization, but rather desorption into the dissolved phase. Copyright © 2013 Elsevier Ltd. All rights reserved.

  8. Coagulation processes of kaolinite and montmorillonite in calm, saline water

    Science.gov (United States)

    Zhang, Jin-Feng; Zhang, Qing-He; Maa, Jerome P.-Y.

    2018-03-01

    A three dimensional numerical model for simulating the coagulation processes of colloids has been performed by monitoring the time evolution of particle number concentration, the size distribution of aggregates, the averaged settling velocity, the collision frequency, and the collision efficiency in quiescent water with selected salinities. This model directly simulates all interaction forces between particles based on the lattice Boltzmann method (LBM) and the extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) theory, and thus, can reveal the collision and coagulation processes of colloidal suspensions. Although using perfect spherical particles in the modeling, the results were compared with those for kaolinite and montmorillonite suspensions to demonstrate the capability of simulating the responses of these particles with highly irregular shape. The averaged settling velocity of kaolinite aggregates in quiescent saline water reached a maximum of 0.16 mm/s when the salinity increasing to about 3, and then, exhibited little dependence on salinity thereafter. Model simulations results (by choosing specific values that represent kaolinite's characteristics) indicate a similar trend: rapid decrease of the particle number concentration (i.e., rapidly flocculated, and thus, settling velocity also increases rapidly) when salinity increases from 0 to 2, and then, only increased slightly when salinity was further increased from 5 to 20. The collision frequency for kaolinite only decreases slightly with increasing salinity because that the fluid density and viscosity increase slightly in sea water. It suggests that the collision efficiency for kaolinite rises rapidly at low salinities and levels off at high salinity. For montmorillonite, the settling velocity of aggregates in quiescent saline water continuedly increases to 0.022 mm/s over the whole salinity range 0-20, and the collision efficiency for montmorillonite rises with increasing salinities.

  9. Roll-to-roll processed polymer tandem solar cells partially processed from water

    DEFF Research Database (Denmark)

    Larsen-Olsen, Thue Trofod; Andersen, Thomas Rieks; Andreasen, Birgitta

    2012-01-01

    Large area polymer tandem solar cells completely processed using roll-to-roll (R2R) coating and printing techniques are demonstrated. A stable tandem structure was achieved by the use of orthogonal ink solvents for the coating of all layers, including both active layers. Processing solvents...... included water, alcohols and chlorobenzene. Open-circuit voltages close to the expected sum of sub cell voltages were achieved, while the overall efficiency of the tandem cells was found to be limited by the low yielding back cell, which was processed from water based ink. Many of the challenges associated...... with upscaling the multilayer tandem cells were identified giving valuable information for future experiments and development....

  10. Increasing process integrity in global scale water balance models

    Science.gov (United States)

    Plöger, Lisa; Mewes, Benjamin; Oppel, Henning; Schumann, Andreas

    2017-04-01

    Hydrological models on a global or continental scale are often used to model human impact on the water balance in data scarce regions. Therefore, they are not validated for a time series of runoff measured at gauges but for long term estimates. The simplistic model GlobWat was introduced by the FAO to predict irrigation water demand based on open source data for continental catchments. Originally, the model was not designed to process time series, but to estimate the water demand on long-time averages of precipitation and evapotranspiration. Therefore the emphasis of detail of GlobWat was focused on crop evapotranspiration and water availability in agricultural regions. In our study we wanted to enhance the modelling in detail to forest evapotranspiration on the one hand and to time series simulation on the other hand. Meanwhile, we tried to keep the amount of input data as small as possible or at least limit it to open source data. Our objectives derived from case studies in the forest dominated catchments of Danube and Mississippi. With the use of Penman-Montheith equation as fundamental equation within the original GlobWat model, evapotranspiration losses in these regions could not be simulated adequately. As this being the fact, the water availability of downstream regions dominated by agriculture might be overestimated and hence estimation of irrigation demands biased. Therefore, we implemented a Shuttleworth & Calder as well as a Priestly-Taylor approach for evapotranspiration calculation of forested areas. Both models are compared and evaluated based on monthly time series validation of the model with runoff series provided by GRDC (Global Runoff Data Center). For an additional extension of the model we added a simple one-parameter snow-routine. In our presentation we compare the different stages of modelling to demonstrate the options to extent and validate these models with observed data on an appropriate scale.

  11. Treating high-mercury-containing lamps using full-scale thermal desorption technology.

    Science.gov (United States)

    Chang, T C; You, S J; Yu, B S; Chen, C M; Chiu, Y C

    2009-03-15

    The mercury content in high-mercury-containing lamps are always between 400 mg/kg and 200,000 mg/kg. This concentration is much higher than the 260 mg/kg lower boundary recommended for the thermal desorption process suggested by the US Resource Conservation and Recovery Act. According to a Taiwan EPA survey, about 4,833,000 cold cathode fluorescent lamps (CCFLs), 486,000 ultraviolet lamps and 25,000 super high pressure mercury lamps (SHPs) have been disposed of in the industrial waste treatment system, producing 80, 92 and 9 kg-mercury/year through domestic treatment, offshore treatment and air emissions, respectively. To deal with this problem we set up a full-scale thermal desorption process to treat and recover the mercury from SHPs, fluorescent tube tailpipes, fluorescent tubes containing mercury-fluorescent powder, and CCFLs containing mercury-fluorescent powder and monitor the use of different pre-heating temperatures and desorption times. The experimental results reveal that the average thermal desorption efficiency of SHPs and fluorescent tube tailpipe were both 99.95%, while the average thermal desorption efficiencies of fluorescent tubes containing mercury-fluorescent powder were between 97% and 99%. In addition, a thermal desorption efficiency of only 69.37-93.39% was obtained after treating the CCFLs containing mercury-fluorescent powder. These differences in thermal desorption efficiency might be due to the complexity of the mercury compounds contained in the lamps. In general, the thermal desorption efficiency of lamps containing mercury-complex compounds increased with higher temperatures.

  12. The Design and Development of Enhanced Thermal Desorption Products

    Directory of Open Access Journals (Sweden)

    R. Humble

    2005-01-01

    Full Text Available This research study is based on a knowledge-transfer collaboration between The National Centre for Product Design and Development Research (PDR and Markes International Ltd. The aim of the two-year collaboration has been to implement design tools and techniques for the development of enhanced thermal desorption products. Thermal desorption is a highly-specialised technique for the analysis of trace-level volatile organic compounds. This technique allows minute quantities of these compounds to be measured; however, there is an increasing demand from customers for greater sensitivity over a wider range of applications, which means new design methodologies need to be evaluated. The thermal desorption process combines a number of disparate chemical, thermal and mechanical disciplines, and the major design constraints arise from the need to cycle the sample through extremes in temperature. Following the implementation of a comprehensive product design specification, detailed design solutions have been developed using the latest 3D CAD techniques. The impact of the advanced design techniques is assessed in terms of improved product performance and reduced development times, and the wider implications of new product development within small companies are highlighted.  

  13. Deuterium desorption from tungsten using laser heating

    Directory of Open Access Journals (Sweden)

    J.H. Yu

    2017-08-01

    Full Text Available Retention and desorption of hydrogenic species need to be accurately modeled to predict the tritium inventory of next generation fusion devices, which is needed both for tritium fuel recovery and for tritium safety concerns. In this paper, experiments on thermal desorption of deuterium from intrinsic polycrystalline tungsten defects using laser heating are compared to TMAP-7 modeling. The samples during deuterium plasma exposure were at a temperature of 373K for this benchmark study with ion fluence of 0.7–1.0 ×1024Dm−2. Following plasma exposure, a fiber laser (λ= 1100nm heated the samples to peak surface temperatures ranging from ∼500 to 1400K with pulse widths from 10ms to 1s, and 1 to 10 pulses applied to each sample. The remaining deuterium retention was measured using temperature programmed desorption (TPD. Results show that > 95% of deuterium is desorbed when the peak surface temperature reached ∼950K for > 1s. TMAP-7 is used to predict deuterium desorption from tungsten for a range of surface temperatures and heating durations, and is compared to previous work on desorption from beryllium codeposits.

  14. Essentials of water systems design in the oil, gas, and chemical processing industries

    CERN Document Server

    Bahadori, Alireza; Boyd, Bill

    2013-01-01

    Essentials of Water Systems Design in the Oil, Gas and Chemical Processing Industries provides valuable insight for decision makers by outlining key technical considerations and requirements of four critical systems in industrial processing plants—water treatment systems, raw water and plant water systems, cooling water distribution and return systems, and fire water distribution and storage facilities. The authors identify the key technical issues and minimum requirements related to the process design and selection of various water supply systems used in the oil, gas, and chemical processing industries. This book is an ideal, multidisciplinary work for mechanical engineers, environmental scientists, and oil and gas process engineers.

  15. Investigations on ion-beam induced desorption from cryogenic surfaces; Untersuchungen zu ionenstrahlinduzierter Desorption von kryogenen Oberflaechen

    Energy Technology Data Exchange (ETDEWEB)

    Maurer, Christoph

    2017-07-03

    A central component of FAIR, the Facility for Antiproton and Ion Research, will be the superconducting heavy ion synchrotron SIS100, which is supposed to provide reliable, high intensity beams for various applications. Its beam intensity is governed by the space charge limit, while the maximum energy is determined by the machine's magnetic rigidity. That means, ions with higher charge state can be accelerated to a higher energy, but with less intensity. For highest intensity beams, intermediate charge states have to be used instead of high charge state ions. This alleviates the issue of space charge but gives rise to dynamic vacuum effects, which also limit beam intensity: beam particles collide with residual gas particles, which leads to charge exchange and their subsequent loss. Impacting on the chamber wall, these ions release adsorbed gas particles. This process is called desorption and leads to a localized increase in pressure, which in turn causes more charge exchange. After a few rounds of self amplification, this can lead to total beam loss. This ''runaway-desorption'' is typically the main beam intensity limiting process for intermediate charge state (heavy) ion beams. The extent of this phenomenon is governed by two factors: the initial beam intensity and the desorption yield. The latter is examined within the scope of this thesis. Special emphasis is placed on the influence of the target's temperature, since the SIS100 will be a superconducting machine with cryogenic vacuum chamber walls. In order to investigate this topic, an experimental setup has been devised, built at the SIS18 and taken into commission. Based on the experience gained during operation, it has been continuously improved and extended. Another central innovation presented in this thesis is the use of gas dynamics simulations for an improved method of data analysis. Using this technique, environmental conditions like the chamber geometry and the connected

  16. Development of an integrated membrane process for water reclamation.

    Science.gov (United States)

    Lew, C H; Hu, J Y; Song, L F; Lee, L Y; Ong, S L; Ng, W J; Seah, H

    2005-01-01

    An integrated membrane process (IMP) comprising a membrane bioreactor (MBR) and a reverse osmosis (RO) process was developed for water reclamation. Wastewater was treated by an MBR operated at a sludge retention time (SRT) of 20 days and a hydraulic retention time (HRT) of 5.5 h. The IMP had an overall recovery efficiency of 80%. A unique feature of the IMP was the recycling of a fraction of RO concentrate back to the MBR. Experimental results revealed that a portion of the slow- and hard-to-degrade organic constituents in the recycle stream could be degraded by an acclimated biomass leading to an improved MBR treatment efficiency. Although recycling concentrated constituents could impose an inhibitory effect on the biomass and suppress their respiratory activities, results obtained suggested that operating MBR (in the novel IMP) at an F/M ratio below 0.03 g TOC/g VSS.day could yield an effluent quality comparable to that achievable without concentrate recycling. It is noted in this study that the novel IMP could achieve an average overall TOC removal efficiency of 88.940% and it consistently produced product water usable for high value reuse applications.

  17. Advanced Control Synthesis for Reverse Osmosis Water Desalination Processes.

    Science.gov (United States)

    Phuc, Bui Duc Hong; You, Sam-Sang; Choi, Hyeung-Six; Jeong, Seok-Kwon

    2017-11-01

      In this study, robust control synthesis has been applied to a reverse osmosis desalination plant whose product water flow and salinity are chosen as two controlled variables. The reverse osmosis process has been selected to study since it typically uses less energy than thermal distillation. The aim of the robust design is to overcome the limitation of classical controllers in dealing with large parametric uncertainties, external disturbances, sensor noises, and unmodeled process dynamics. The analyzed desalination process is modeled as a multi-input multi-output (MIMO) system with varying parameters. The control system is decoupled using a feed forward decoupling method to reduce the interactions between control channels. Both nominal and perturbed reverse osmosis systems have been analyzed using structured singular values for their stabilities and performances. Simulation results show that the system responses meet all the control requirements against various uncertainties. Finally the reduced order controller provides excellent robust performance, with achieving decoupling, disturbance attenuation, and noise rejection. It can help to reduce the membrane cleanings, increase the robustness against uncertainties, and lower the energy consumption for process monitoring.

  18. Petroleum coke adsorption as a water management option for oil sands process-affected water

    Energy Technology Data Exchange (ETDEWEB)

    Zubot, Warren [Syncrude Canada Ltd., Research and Development, Edmonton, Alberta, Canada T6N 1H4 (Canada); MacKinnon, Michael D. [OSPM Solutions Ltd., Hamilton, Ontario, Canada L8H 6X2 (Canada); Chelme-Ayala, Pamela; Smith, Daniel W. [University of Alberta, Department of Civil and Environmental Engineering, Edmonton, Alberta, Canada T6G 2W2 (Canada); Gamal El-Din, Mohamed, E-mail: mgamalel-din@ualberta.ca [University of Alberta, Department of Civil and Environmental Engineering, Edmonton, Alberta, Canada T6G 2W2 (Canada)

    2012-06-15

    Water is integral to both operational and environmental aspects of the oil sands industry. A water treatment option based on the use of petroleum coke (PC), a by-product of bitumen upgrading, was examined as an opportunity to reduce site oil sands process-affected water (OSPW) inventories and net raw water demand. Changes in OSPW quality when treated with PC included increments in pH levels and concentrations of vanadium, molybdenum, and sulphate. Constituents that decreased in concentration after PC adsorption included total acid-extractable organics (TAO), bicarbonate, calcium, barium, magnesium, and strontium. Changes in naphthenic acids (NAs) speciation were observed after PC adsorption. A battery of bioassays was used to measure the OSPW toxicity. The results indicated that untreated OSPW was toxic towards Vibrio fischeri and rainbow trout. However, OSPW treated with PC at appropriate dosages was not acutely toxic towards these test organisms. Removal of TAO was found to be an adsorption process, fitting the Langmuir and Langmuir-Freundlich isotherm models. For TAO concentrations of 60 mg/L, adsorption capacities ranged between 0.1 and 0.46 mg/g. This study demonstrates that freshly produced PC from fluid cokers provides an effective treatment of OSPW in terms of key constituents' removal and toxicity reduction. - Highlights: Black-Right-Pointing-Pointer Treatment of oil sands process-affected water (OSPW) using petroleum coke (PC) adsorption was investigated. Black-Right-Pointing-Pointer PC was effective at adsorbing naphthenic acids with higher cyclicity. Black-Right-Pointing-Pointer OSPW treated with PC at appropriate dosages was not toxic towards Vibrio fisheri and rainbow trout. Black-Right-Pointing-Pointer The adsorption of organic acids fitted the Langmuir and Langmuir-Freundlich isotherm models. Black-Right-Pointing-Pointer PC has the potential to be an effective adsorbent to treat OSPW either directly or as a pretreatment step.

  19. Film growth, adsorption and desorption kinetics of indigo on SiO2

    Science.gov (United States)

    Scherwitzl, Boris; Resel, Roland; Winkler, Adolf

    2014-05-01

    Organic dyes have recently been discovered as promising semiconducting materials, attributable to the formation of hydrogen bonds. In this work, the adsorption and desorption behavior, as well as thin film growth was studied in detail for indigo molecules on silicon dioxide with different substrate treatments. The material was evaporated onto the substrate by means of physical vapor deposition under ultra-high vacuum conditions and was subsequently studied by Thermal Desorption Spectroscopy (TDS), Auger Electron Spectroscopy, X-Ray Diffraction, and Atomic Force Microscopy. TDS revealed initially adsorbed molecules to be strongly bonded on a sputter cleaned surface. After further deposition a formation of dimers is suggested, which de-stabilizes the bonding mechanism to the substrate and leads to a weakly bonded adsorbate. The dimers are highly mobile on the surface until they get incorporated into energetically favourable three-dimensional islands in a dewetting process. The stronger bonding of molecules within those islands could be shown by a higher desorption temperature. On a carbon contaminated surface no strongly bonded molecules appeared initially, weakly bonded monomers rather rearrange into islands at a surface coverage that is equivalent to one third of a monolayer of flat-lying molecules. The sticking coefficient was found to be unity on both substrates. The desorption energies from carbon covered silicon dioxide calculated to 1.67 ± 0.05 eV for multilayer desorption from the islands and 0.84 ± 0.05 eV for monolayer desorption. Corresponding values for desorption from a sputter cleaned surface are 1.53 ± 0.05 eV for multilayer and 0.83 ± 0.05 eV for monolayer desorption.

  20. Film growth, adsorption and desorption kinetics of indigo on SiO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Scherwitzl, Boris, E-mail: b.scherwitzl@tugraz.at; Resel, Roland; Winkler, Adolf [Institute of Solid State Physics, Graz University of Technology, Petersgasse 16, A-8010 Graz (Austria)

    2014-05-14

    Organic dyes have recently been discovered as promising semiconducting materials, attributable to the formation of hydrogen bonds. In this work, the adsorption and desorption behavior, as well as thin film growth was studied in detail for indigo molecules on silicon dioxide with different substrate treatments. The material was evaporated onto the substrate by means of physical vapor deposition under ultra-high vacuum conditions and was subsequently studied by Thermal Desorption Spectroscopy (TDS), Auger Electron Spectroscopy, X-Ray Diffraction, and Atomic Force Microscopy. TDS revealed initially adsorbed molecules to be strongly bonded on a sputter cleaned surface. After further deposition a formation of dimers is suggested, which de-stabilizes the bonding mechanism to the substrate and leads to a weakly bonded adsorbate. The dimers are highly mobile on the surface until they get incorporated into energetically favourable three-dimensional islands in a dewetting process. The stronger bonding of molecules within those islands could be shown by a higher desorption temperature. On a carbon contaminated surface no strongly bonded molecules appeared initially, weakly bonded monomers rather rearrange into islands at a surface coverage that is equivalent to one third of a monolayer of flat-lying molecules. The sticking coefficient was found to be unity on both substrates. The desorption energies from carbon covered silicon dioxide calculated to 1.67 ± 0.05 eV for multilayer desorption from the islands and 0.84 ± 0.05 eV for monolayer desorption. Corresponding values for desorption from a sputter cleaned surface are 1.53 ± 0.05 eV for multilayer and 0.83 ± 0.05 eV for monolayer desorption.

  1. A linearized path integral description of the collision process between a water molecule and a graphite surface.

    Science.gov (United States)

    Marković, Nikola; Poulsen, Jens A

    2008-02-28

    Quantum effects in the scattering and desorption process of a water molecule from a graphite surface are investigated using the linearized path integral model. The graphite surface is quantized rigorously using the fully quantum many-body Wigner transform of the surface Boltzmann operator, while the water molecule is treated as rigid. Classical dynamics with these quantized initial conditions show that quantizing the surface at 100 and 300 K results in markedly different results, compared to a fully classical analysis. The trapping probability (defined as the probability of multiple encounters with the surface) is not sensitive to the choice of dynamical treatment, but the residence time on the surface is much shorter in the quantum case. At 300 K the transiently trapped molecules desorb from the surface with a rate constant which is 60-70% larger than the corresponding classical value. Lowering the surface temperature to 100 K decreases the quantum rate constant by approximately a factor of 3 while all trapped molecules stick to the surface in the classical case. The stability of the quantum initial state for the highly anisotropic graphite crystal is discussed in detail as well as the dynamical consequences of energy redistribution during the scattering process. The graphite surface application demonstrates that the Boltzmann operator Wigner transform for a system with 900 degrees of freedom can be obtained by the so-called gradient implementation [Poulsen et al. J. Chem. Theory Comput. 2006, 2, 1482] of the underlying Feynman-Kleinert effective frequency theory, an implementation that only requires a force and potential routine for the system at hand, and hence is applicable to any molecule-surface collision problem.

  2. ATRAZINE ADSORPTION-DESORPTION BEHAVIOR IN DAREHASALUIE KAVAR CORN FIELD SOIL

    Directory of Open Access Journals (Sweden)

    M. Dehghani, S. Nasseri, S. Amin, K. Naddafi, M. Yunesian, M. Taghavi and N. Maleki

    2005-10-01

    Full Text Available Adsorption desorption behaviors of widely applied atrazine soil were studied, employing a batch technique as a case study in Darehasaluie Kavar corn field in Fars Province in 2005. Samples were collected into 0 to 20 cm soil depth, where was cultivated under a crop rotation (corn-wheat during the past 10 years. Sorption kinetics exhibited two phenomena: an immediate rapid sorption (1.31 µg/g soil after 12 hours followed by a slow sorption process (1.37 µg/g soil after 24 hours. Desorption behavior of atrazine was similar to its adsorption, but at a very slower rate. Atrazine desorption efficiencies were much less effective and incomplete even after a long equilibration time (only 9.16% after 96 hours. The adsorption-desorption rate for most of the time was positively related to the amount of applied atrazine and the time required for equilibration (P<0.01. Desorption data exhibited hysteresis phenomena. Atrazine adsorption data described well according to Freundlich (r2=0.95, Langmuir (r2=0.82 and Temkin (r2=0.84 isotherms. However, the fit to Freundlich adsorption model in a non linear form (1/n <1 was closer than the others. Desorption isotherm could be well described by the Temkin (r2=0.96 and Freundlich (r2=0.92 isotherms, but the fit to Temkin model was closer than that of Freundlich.

  3. Thermal desorption mass spectrometric and x-ray photoelectron studies of etched surfaces of polytetrafluoroethylene

    Science.gov (United States)

    Rye, R. R.; Kelber, J. A.

    1987-12-01

    The etching of polytetrafluoroethylene (PTFE) with Na solutions is known to lead to a loss of F, a loss which is correlated with enhanced adhesion. Subsequent heating partially restores surface F with a concurrent loss of adhesion strength. We have combined X-ray photoelectron spectroscopy (XPS) and gas phase mass spectroscopy for in situ measurements of the processes that occur as the fluorocarbon is heated. An array of volatile products, which vary with the specific treatment, desorb from etched PTFE. Among these are: N 2 and low molecular weight fluorocarbons, the amounts of which monotonically decrease with increasing exposure to the etching solution (and probably result from the bulk); species such as CO and CO 2, which in part result from surface impurities; and water and acetone which result from the rinse steps following the etching process. XPS measurements show that etching produces a major loss of surface F and a gain of surface O. The latter probably results from the subsequent rinse steps. Heating produces a substantial recovery in surface F with only a small decrease in the surface O, and the gain in surface F is shown to occur at a higher temperature than the desorption of any species from the surface. Thus, desorption of products from the surface is decoupled, in terms of both the distribution of products and their relative temperatures, from the surface changes as monitored by XPS. This decoupling suggests that the increase in surface F results from diffusion of low molecular weight fluorocarbons from the bulk or a transition region, or from a rearrangement of the sponge-like surface region produced in the etching process.

  4. Occupational allergy and asthma among salt water fish processing workers.

    Science.gov (United States)

    Jeebhay, Mohamed F; Robins, Thomas G; Miller, Mary E; Bateman, Eric; Smuts, Marius; Baatjies, Roslynn; Lopata, Andreas L

    2008-12-01

    Fish processing is a common economic activity in Southern Africa. The aim of this study was to determine the prevalence and host determinants of allergic symptoms, allergic sensitization, bronchial hyper-responsiveness and asthma among workers processing saltwater fish. A cross-sectional study was conducted on 594 currently employed workers in two processing plants involved in pilchard canning and fishmeal processing. A modified European Community Respiratory Health Survey (ECRHS) questionnaire was used. Skin prick tests (SPT) used extracts of common airborne allergens, fresh fish (pilchard, anchovy, maasbanker, mackerel, red eye) and fishmeal. Spirometry and methacholine challenge tests (MCTs; tidal breathing method) used ATS guidelines. Work-related ocular-nasal symptoms (26%) were more common than asthma symptoms (16%). The prevalence of atopy was 36%, while 7% were sensitized to fish species and 26% had NSBH (PC(20) or =12% increase in FEV(1) post-bronchodilator). The prevalence of probable occupational asthma was 1.8% and fish allergic rhino-conjunctivitis 2.6%. Women were more likely to report work-related asthma symptoms (OR = 1.94) and have NSBH (OR = 3.09), while men were more likely to be sensitized to fish (OR = 2.06) and have airway obstruction (OR = 4.17). Atopy (OR = 3.16) and current smoking (OR = 2.37), but not habitual seafood consumption were associated with sensitization to fish. Based on comparison with previous published studies, the prevalence of occupational asthma to salt water fish is lower than due to shellfish. The gendered distribution of work and exposures in fish processing operations together with atopy and cigarette smoking are important determinants of occupational allergy and asthma. Copyright 2008 Wiley-Liss, Inc.

  5. Recovery of ethanol from fermentation broths using selective sorption-desorption.

    Science.gov (United States)

    Pitt, W W; Haag, G L; Lee, D D

    1983-01-01

    Industrialized nations face a critical problem in replacing the sources of liquid fuels that traditionally have been supplied by petroleum. One solution that has gained increasing support in this country is the use of ethanol produced by fermentation of renewable biomass as an extender in, or supplement to, gasoline for transportation fuel. Distillation, the present method of separating ethanol from the fermentation broth, is an energy-intensive one and frequently uses more energy than is available from the ethanol recovered. There are many investigations under way to find alternative, less energy-intensive techniques for the ethanol-water separation. The separations method described in this article involves the use of solid materials to preferentially remove ethanol from fermentation broths. Subsequent stripping of the ethanol from the sorbent with a dry gas reduces dramatically the energy required for the separation. Three solid sorbents have been investigated experimentally. Their sorption/desorption characteristics are described, and their incorporation in an ethanol recovery process is evaluated. Three sorbents were investigated: two commercially available divinylbenzene crosslinked polystyrene resins in bead form (one with a nominal surface area of 300 m(2)/g, the other with 750 m(2)/g) and an experimental proprietary molecular sieve with hydrophobic properties. Equilibrium adsorption isotherms for two of the sorbents were obtained at ambient temperature (21 degrees C) for ethanol-water solutions containing up to 12 wt. % ethanol. In addition, 40 degrees C isotherms were obtained for the polystyrene sorbents. Although different, the equilibrium isotherms for the sorbents indicated that ethanol could be preferentially sorbed from a dilute solution. Column breakthrough curves indicated very favorable kinetics. Desorption of the ethanol was readily effected with warm (60-80 degrees C), dry nitrogen.

  6. Reactor process water (PW) piping inspections, 1984--1990

    Energy Technology Data Exchange (ETDEWEB)

    Ehrhart, W.S.; Elder, J.B.; Sprayberry, R.E.; Vande Kamp, R.W.

    1990-12-31

    In July 1983, the NRC ordered the shutdown of five boiling water reactors (BWR`s) because of concerns about reliability of ultrasonic examination for detecting intergranular stress corrosion cracking (IGSCC). These concerns arose because of leaking piping at Niagara Mohawk`s Nine Mile Point which was attributed to IGSCC. The leaks were detected shortly after completion of ultrasonic examinations of the piping. At that time, the Dupont plant manager at Savannah River (SR) directed that investigations be performed to determine if similar problems could exist in SR reactors. Investigation determined that all conditions believed necessary for the initiation and propagation of IGSCC in austenitic stainless steel exist in SR reactor process water (PW) systems. Sensitized, high carbon, austenitic stainless steel, a high purity water system with high levels of dissolved oxygen, and the residual stresses associated with welding during construction combine to provide the necessary conditions. A periodic UT inspection program is now in place to monitor the condition of the reactor PW piping systems. The program is patterned after NRC NUREG 0313, i.e., welds are placed in categories based on their history. Welds in upgraded or replacement piping are examined on a standard schedule (at least every five years) while welds with evidence of IGSCC, evaluated as acceptable for service, are inspected at every extended outage (15 to 18 months). This includes all welds in PW systems three inches in diameter and above. Welds are replaced when MSCC exceeds the replacement criteria of more than twenty percent of pipe circumference of fifty percent of through-wall depth. In the future, we intend to perform flow sizing with automated UT techniques in addition to manual sizing to provide more information for comparison with future examinations.

  7. Reactor process water (PW) piping inspections, 1984--1990

    Energy Technology Data Exchange (ETDEWEB)

    Ehrhart, W.S.; Elder, J.B.; Sprayberry, R.E.; Vande Kamp, R.W.

    1990-01-01

    In July 1983, the NRC ordered the shutdown of five boiling water reactors (BWR's) because of concerns about reliability of ultrasonic examination for detecting intergranular stress corrosion cracking (IGSCC). These concerns arose because of leaking piping at Niagara Mohawk's Nine Mile Point which was attributed to IGSCC. The leaks were detected shortly after completion of ultrasonic examinations of the piping. At that time, the Dupont plant manager at Savannah River (SR) directed that investigations be performed to determine if similar problems could exist in SR reactors. Investigation determined that all conditions believed necessary for the initiation and propagation of IGSCC in austenitic stainless steel exist in SR reactor process water (PW) systems. Sensitized, high carbon, austenitic stainless steel, a high purity water system with high levels of dissolved oxygen, and the residual stresses associated with welding during construction combine to provide the necessary conditions. A periodic UT inspection program is now in place to monitor the condition of the reactor PW piping systems. The program is patterned after NRC NUREG 0313, i.e., welds are placed in categories based on their history. Welds in upgraded or replacement piping are examined on a standard schedule (at least every five years) while welds with evidence of IGSCC, evaluated as acceptable for service, are inspected at every extended outage (15 to 18 months). This includes all welds in PW systems three inches in diameter and above. Welds are replaced when MSCC exceeds the replacement criteria of more than twenty percent of pipe circumference of fifty percent of through-wall depth. In the future, we intend to perform flow sizing with automated UT techniques in addition to manual sizing to provide more information for comparison with future examinations.

  8. Integral water treatment plant modeling: improvements for particle processes.

    Science.gov (United States)

    Lawler, Desmond F; Nason, Jeffrey A

    2005-09-01

    An update of research on particle behavior in water treatment plants first performed 25 years ago under the direction of Charles O'Melia is provided. The earlier work involved mathematical modeling of the changes in particle size distributions in the flocculation and sedimentation processes in water treatment plants. The current model includes corrections for short-range interactions between particles as they approach one another. These corrections severely reduce the expected collision frequency between particles that are very different in size and, therefore, substantially change the model predictions. Both experimental and field measurements of particle size distributions are provided; such measurements were unavailable in the earlier work and represent a touchstone to reality for the modeling efforts. The short-range model successfully fits experimental results for flocculation when the mechanism of particle destabilization is charge neutralization. However, the model does not account for the creation of new solids by precipitation either when hydrolyzing salts of aluminum or iron are added for particle destabilization by "sweep floc" destabilization or lime is added to remove calcium and magnesium as calcium carbonate and magnesium hydroxide in softening. The flocculent sedimentation model yields results that are in strong qualitative agreement with typical field measurements.

  9. The desorption of ammonia and carbon dioxide from multicomponent solutions: I. Model description and development

    Directory of Open Access Journals (Sweden)

    Jotanović Milovan B.

    2002-01-01

    Full Text Available A mathematical model of the desorption process based on the synthesised technological topology of the regeneration process gas components NH3 and CO2, was developed. The logical principle methodology of the mathematical modelling of desorption processes was worked out in detail. The mathematical model of the process, including the following: - The synthesized technological scheme of the desorption of components NH3 and CO2, with all the necessary requirements and limitations of the mathematical model; - The relevant multicomponent systems which exist in the process were defined in which the interphase transformation occurs; - The considered units (aparatus are defined which make up the basic technological topology of the process; - Desorption processes in towers with different types of trays were defined and mathematically described; - The cooling process and condensation of gas phase in a complex multicomponent system was of the gas phase in a complex multicomponent system was defined and mathematically described. Many variants of the process were analyzed by using developed model with the aim of determining the relevant functional dependences between some basic parameters of the process. They will be published in the second part of this study.

  10. Development of regulations for water care works and process ...

    African Journals Online (AJOL)

    It is well known that South Africa is a water scarce country and that return of high quality effluents to the water resources is essential. In terms of the National Water Act, 1998 (Act 36 of 1998) the National Government has public trusteeship of the nation's water resources and therefore, acting through the Minister, must ensure ...

  11. Coupling biophysical processes and water rights to simulate spatially distributed water use in an intensively managed hydrologic system

    Science.gov (United States)

    Han, Bangshuai; Benner, Shawn G.; Bolte, John P.; Vache, Kellie B.; Flores, Alejandro N.

    2017-07-01

    Humans have significantly altered the redistribution of water in intensively managed hydrologic systems, shifting the spatiotemporal patterns of surface water. Evaluating water availability requires integration of hydrologic processes and associated human influences. In this study, we summarize the development and evaluation of an extensible hydrologic model that explicitly integrates water rights to spatially distribute irrigation waters in a semi-arid agricultural region in the western US, using the Envision integrated modeling platform. The model captures both human and biophysical systems, particularly the diversion of water from the Boise River, which is the main water source that supports irrigated agriculture in this region. In agricultural areas, water demand is estimated as a function of crop type and local environmental conditions. Surface water to meet crop demand is diverted from the stream reaches, constrained by the amount of water available in the stream, the water-rights-appropriated amount, and the priority dates associated with particular places of use. Results, measured by flow rates at gaged stream and canal locations within the study area, suggest that the impacts of irrigation activities on the magnitude and timing of flows through this intensively managed system are well captured. The multi-year averaged diverted water from the Boise River matches observations well, reflecting the appropriation of water according to the water rights database. Because of the spatially explicit implementation of surface water diversion, the model can help diagnose places and times where water resources are likely insufficient to meet agricultural water demands, and inform future water management decisions.

  12. Quantum theory of laser-stimulated desorption

    Science.gov (United States)

    Slutsky, M. S.; George, T. F.

    1978-01-01

    A quantum theory of laser-stimulated desorption (LSDE) is presented and critically analyzed. It is shown how LSDE depends on laser-pulse characteristics and surface-lattice dynamics. Predictions of the theory for a Debye model of the lattice dynamics are compared to recent experimental results.

  13. Water reuse in the l-lysine fermentation process

    Energy Technology Data Exchange (ETDEWEB)

    Hsiao, T.Y.; Glatz, C.E. [Iowa State Univ., Ames, IA (United States). Dept. of Chemical Engineering

    1996-02-05

    L-Lysine is produced commercially by fermentation. As is typical for fermentation processes, a large amount of liquid waste is generated. To minimize the waste, which is mostly the broth effluent from the cation exchange column used for l-lysine recovery, the authors investigated a strategy of recycling a large fraction of this broth effluent to the subsequent fermentation. This was done on a lab-scale process with Corynebacterium glutamicum ATCC 21253 as the l-lysine-producing organisms. Broth effluent from a fermentation in a defined medium was able to replace 75% of the water for the subsequent batch; this recycle ratio was maintained for 3 sequential batches without affecting cell mass and l-lysine production. Broth effluent was recycled at 50% recycle ratio in a fermentation in a complex medium containing beet molasses. The first recycle batch had an 8% lower final l-lysine level, but 8% higher maximum cell mass. In addition to reducing the volume of liquid waste, this recycle strategy has the additional advantage of utilizing the ammonium desorbed from the ion-exchange column as a nitrogen source in the recycle fermentation. The major problem of recycling the effluent from the complex medium was in the cation-exchange operation, where column capacity was 17% lower for the recycle batch. The loss of column capacity probably results from the buildup of cations competing with l-lysine for binding.

  14. ABOUT PHYSICOCHEMICAL PROCESSES AT ELECTROLYTIC DECOMPOZITION OF THE WATER

    Directory of Open Access Journals (Sweden)

    Berzan V.P.

    2006-04-01

    Full Text Available Physical processes are investigated at electrolyze waters from the power point of view at small density of a current.Reception of hydrogen is possible not only at the well-known charge of the electric power exceeding energy which can be received at burning this hydrogen (about 12 MJ/m3, but under some conditions and at the smaller charge of the electric power. The minimal density of a current (10 А/m2 is determined at which restoration of ions of gases occurs in the energy-economic way, and also value of density of a current (107А/m2 at which in a solution of electrolyte begin plasma discharges.It is experimentally shown, that if the condition of maintenance of the minimal density of a current is carried out only on one electrode also liberation of gas occurs on it as short-term transient. The kind of this gas (hydrogen or oxygen is determined by polarity of a supplay of electrolitical cell. Values of a voltage at which gas on electrodes is not recepted are experimentally determined, is receipt on one electrode and gas starts will be receipt on both electrodes of a cell.Processes which existence it is possible to explain only passage electrons through electrolyte are revealed as well.

  15. Comparison of drinking water treatment process streams for optimal bacteriological water quality.

    Science.gov (United States)

    Ho, Lionel; Braun, Kalan; Fabris, Rolando; Hoefel, Daniel; Morran, Jim; Monis, Paul; Drikas, Mary

    2012-08-01

    Four pilot-scale treatment process streams (Stream 1 - Conventional treatment (coagulation/flocculation/dual media filtration); Stream 2 - Magnetic ion exchange (MIEX)/Conventional treatment; Stream 3 - MIEX/Conventional treatment/granular activated carbon (GAC) filtration; Stream 4 - Microfiltration/nanofiltration) were commissioned to compare their effectiveness in producing high quality potable water prior to disinfection. Despite receiving highly variable source water quality throughout the investigation, each stream consistently reduced colour and turbidity to below Australian Drinking Water Guideline levels, with the exception of Stream 1 which was difficult to manage due to the reactive nature of coagulation control. Of particular interest was the bacteriological quality of the treated waters where flow cytometry was shown to be the superior monitoring tool in comparison to the traditional heterotrophic plate count method. Based on removal of total and active bacteria, the treatment process streams were ranked in the order: Stream 4 (average log removal of 2.7) > Stream 2 (average log removal of 2.3) > Stream 3 (average log removal of 1.5) > Stream 1 (average log removal of 1.0). The lower removals in Stream 3 were attributed to bacteria detaching from the GAC filter. Bacterial community analysis revealed that the treatments affected the bacteria present, with the communities in streams incorporating conventional treatment clustering with each other, while the community composition of Stream 4 was very different to those of Streams 1, 2 and 3. MIEX treatment was shown to enhance removal of bacteria due to more efficient flocculation which was validated through the novel application of the photometric dispersion analyser. Copyright © 2012 Elsevier Ltd. All rights reserved.

  16. Adsorption and desorption of phosphate on limestone in experiments simulating seawater intrusion

    Science.gov (United States)

    The absorption and desorption of phosphorus on a large block of limestone was investigated using deionized water (DIW) and seawater. The limestone had a high affinity to adsorb phosphorus in DIW. Phosphate adsorption was significantly less in seawater, and more phosphorus was desorbed in the seawate...

  17. Ultrasound-assisted advanced oxidation processes for water decontamination.

    Science.gov (United States)

    Ince, Nilsun H

    2017-04-09

    The study reflects a part of my experience in sonochemistry and ultrasound-assisted advanced oxidation processes (AOPs) acquired during the last fifteen years with my research team. The data discussed were selected from studies with azo dyes, endocrine disrupting compounds and analgesic/anti-inflammatory pharmaceuticals, which are all classified as "hazardous" or "emerging" contaminants. The research focused on their treatability by ultrasound (US) and AOPs with emphasis on the mineralization of organic carbon. Some of the highlights as pointed out in the manuscript are: i) ultrasound is capable of partially or completely oxidizing the above contaminant groups if the operating conditions are properly selected and optimized, but incapable of mineralizing them; ii) the mechanism of degradation in homogeneous solutions is OH-mediated oxidation in the bulk solution or at the bubble-liquid interface, depending on the molecular properties of the contaminant, the applied frequency and pH; iii) US-assisted AOPs such as ozonation, UV/peroxide, Fenton and UV/Fenton are substantially more effective than ultrasound alone, particularly for the mineralization process; iv) catalytic processes involving TiO2, alumina and zero-valent iron and assisted by ultrasound are promising options not only for the destruction of the parent compounds, but also for the mineralization of their oxidation byproducts. The degradation reactions in heterogeneous solutions take place mostly at the catalyst surface despite the high-water solubility of the compounds; v) sonolytic modification of the above catalysts to reduce their particle size (to nano-levels) or to decorate the surface with metallic nanoparticles increases the catalytic activity under sonolysis, photolysis and both, and improves the stability of the catalyst. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Experimental design of diffusion and desorption of contaminant in heterogeneous media.

    Science.gov (United States)

    Jiang, Guannan; Crimi, Michelle; Fowler, Kathleen; Fu, Xiaojing

    2011-01-01

    Storage of contaminants in low permeability media (LPM) presents a great challenge for prediction of remediation effectiveness and efficiency. The reason lies in the contaminants' complex behaviors within heterogeneous media. Both interparticle and intraparticle diffusion contribute to the difficulty of precise site assessment. Sorption of contaminants--especially within LPM--may sequester the contaminants from active treatment, while desorption over a long period of time leads to contaminant release from storage and consequent re-contamination. Research has been conducted toward better understanding of contaminant diffusion and sorption/desorption processes to better predict contaminant response to site treatment. However, most of the research has been carried out within homogeneous media, while real scenarios in environmental problems feature media whose permeability and other characteristics vary significantly over the treatment volume. Further, few efforts have combined the interparticle/intraparticle diffusion and sorption/desorption processes together. This research aims at a feasible experimental design of diffusion and desorption of contaminant in heterogeneous media to address the gaps in previous research. A 2-D experimental system was designed to evaluate interparticle/intraparticle diffusion processes of trichloroethylene (TCE) in heterogeneous media. The 2-D system was modified to include organic matter in media for simulation of sorption/desorption processes. Results of the research will improve the understanding of how these different transport processes act together within heterogeneous media. Results will also allow for the evaluation of the impact of contaminant mass transport from within low permeability media at a potential treatment site and can support the development of mathematical tools/models combining interparticle/intraparticle and sorption/desorption processes. Such a model will promote more accurate site assessment and provide more

  19. Study of thermodynamic water properties and moisture sorption hysteresis of mango skin

    Directory of Open Access Journals (Sweden)

    Silvio José Ferreira de Souza

    2015-03-01

    Full Text Available The equilibrium moisture content for adsorption and desorption isotherms of mango skin was determined using the static gravimetric method at temperatures of 20, 26, 33, 38 and 44 oC in the 0.056 to 0.873 water activity range. Both sorption curves show a decrease in equilibrium moisture content as the temperature increasing. The hysteresis effect was observed at constant water activity. The Guggenheim, Anderson, and de Boer (GAB model presented the best fitting accuracy among a group of models and was used to determine the thermodynamic properties of water sorption. Integral enthalpy and integral entropy areas showed inverted values for the adsorption and desorption isotherms over the wide range of water activity studied. These values confirm, in energetic terms, the difference between adsorption and desorption isotherms observed in the hysteresis phenomenon. Finally, the Gibbs free energy revealed that the sorption process was spontaneous for both sorption isotherms.

  20. Example process hazard analysis of a Department of Energy water chlorination process

    Energy Technology Data Exchange (ETDEWEB)

    1993-09-01

    On February 24, 1992, the Occupational Safety and Health Administration (OSHA) released a revised version of Section 29 Code of Federal Regulations CFR Part 1910 that added Section 1910.119, entitled ``Process Safety Management of Highly Hazardous Chemicals`` (the PSM Rule). Because US Department of Energy (DOE) Orders 5480.4 and 5483.1A prescribe OSHA 29 CFR 1910 as a standard in DOE, the PSM Rule is mandatory in the DOE complex. A major element in the PSM Rule is the process hazard analysis (PrHA), which is required for all chemical processes covered by the PSM Rule. The PrHA element of the PSM Rule requires the selection and application of appropriate hazard analysis methods to systematically identify hazards and potential accident scenarios associated with processes involving highly hazardous chemicals (HHCs). The analysis in this report is an example PrHA performed to meet the requirements of the PSM Rule. The PrHA method used in this example is the hazard and operability (HAZOP) study, and the process studied is the new Hanford 300-Area Water Treatment Facility chlorination process, which is currently in the design stage. The HAZOP study was conducted on May 18--21, 1993, by a team from the Westinghouse Hanford Company (WHC), Battelle-Columbus, the DOE, and Pacific Northwest Laboratory (PNL). The chlorination process was chosen as the example process because it is common to many DOE sites, and because quantities of chlorine at those sites generally exceed the OSHA threshold quantities (TQs).

  1. Adsorption and desorption of chlorpyrifos to soils and sediments.

    Science.gov (United States)

    Gebremariam, Seyoum Yami; Beutel, Marc W; Yonge, David R; Flury, Markus; Harsh, James B

    2012-01-01

    Chlorpyrifos, one of the most widely used insecticides, has been detected in air, rain, marine sediments, surface waters, drinking water wells, and solid and liquid dietary samples collected from urban and rural areas. Its metabolite, TCP, has also been widely detected in urinary samples collected from people of various age groups. With a goal of elucidating the factors that control the environmental contamination, impact, persistence, and ecotoxicity of chlorpyrifos, we examine, in this review, the peer-reviewed literature relating to chlorpyrifos adsorption and desorption behavior in various solid-phase matrices. Adsorption tends to reduce chlorpyrifos mobility, but adsorption to erodible particulates, dissolved organic matter, or mobile inorganic colloids enhances its mobility. Adsorption to suspended sediments and particulates constitutes a major off-site migration route for chlorpyrifos to surface waters, wherein it poses a potential danger to aquatic organisms. Adsorption increases the persistence of chlorpyrifos in the environment by reducing its avail- ability to a wide range of dissipative and degradative forces, whereas the effect of adsorption on its ecotoxicity is dependent upon the route of exposure. Chlorpyrifos adsorbs to soils, aquatic sediments, organic matter, and clay minerals to differing degrees. Its adsorption strongly correlates with organic carbon con- tent of the soils and sediments. A comprehensive review of studies that relied on the batch equilibrium technique yields mean and median Kd values for chlorpyrifos of 271 and 116 L/kg for soils, and 385 and 403 L/kg for aquatic sediments. Chlorpyrifos adsorption coefficients spanned two orders of magnitude in soils. Normalizing the partition coefficient to organic content failed to substantially reduce variability to commonly acceptable level of variation. Mean and median values for chlorpyrifos partition coefficients normalized to organic carbon, K, were 8,163 and 7,227 L/kg for soils and 13

  2. Energy implications of water reduction strategies in Kraft process : part 1 : methodology

    Energy Technology Data Exchange (ETDEWEB)

    Mateos-Espejel, E.; Marinova, M.; Barapour, S.; Paris, J. [Ecole Polytechnique, Montreal, PQ (Canada). Dept. de Genie Chimique

    2010-05-15

    This article described a methodology developed to study water and energy interactions during a kraft pulping process at an operating mill. The methodology used process integration tools to analyze water utilization and evaluate opportunities for water savings. A thermal analysis of the kraft process was conducted, and potential water restrictions were considered. The water reduction potential of the process was assessed. A computerized simulation of the proposed water reduction strategies was then designed in order to develop operational changes for the process. The energy implications of water closure on the internal heat recovery system were also assessed, and a trade-off analysis was conducted. Data were obtained from a kraft pulp mill located in eastern Canada. The methodology identified the impact of water reduction strategies on direct energy savings as well as on other potential constraints that may be affected by water re-utilization. 15 refs., 2 tabs., 5 figs.

  3. Characterisation of Dissolved Organic Carbon by Thermal Desorption - Proton Transfer Reaction - Mass Spectrometry

    Science.gov (United States)

    Materić, Dušan; Peacock, Mike; Kent, Matthew; Cook, Sarah; Gauci, Vincent; Röckmann, Thomas; Holzinger, Rupert

    2017-04-01

    Dissolved organic carbon (DOC) is an integral component of the global carbon cycle. DOC represents an important terrestrial carbon loss as it is broken down both biologically and photochemically, resulting in the release of carbon dioxide (CO2) to the atmosphere. The magnitude of this carbon loss can be affected by land management (e.g. drainage). Furthermore, DOC affects autotrophic and heterotrophic processes in aquatic ecosystems, and, when chlorinated during water treatment, can lead to the release of harmful trihalomethanes. Numerous methods have been used to characterise DOC. The most accessible of these use absorbance and fluorescence properties to make inferences about chemical composition, whilst high-performance size exclusion chromatography can be used to determine apparent molecular weight. XAD fractionation has been extensively used to separate out hydrophilic and hydrophobic components. Thermochemolysis or pyrolysis Gas Chromatography - Mass Spectrometry (GC-MS) give information on molecular properties of DOC, and 13C NMR spectroscopy can provide an insight into the degree of aromaticity. Proton Transfer Reaction - Mass Spectrometry (PTR-MS) is a sensitive, soft ionisation method suitable for qualitative and quantitative analysis of volatile and semi-volatile organic vapours. So far, PTR-MS has been used in various environmental applications such as real-time monitoring of volatile organic compounds (VOCs) emitted from natural and anthropogenic sources, chemical composition measurements of aerosols etc. However, as the method is not compatible with water, it has not been used for analysis of organic traces present in natural water samples. The aim of this work was to develop a method based on thermal desorption PTR-MS to analyse water samples in order to characterise chemical composition of dissolved organic carbon. We developed a clean low-pressure evaporation/sublimation system to remove water from samples and thermal desorption system to introduce

  4. Residence time dependent desorption of Staphylococcus epidermidis from hydrophobic and hydrophilic substrata

    NARCIS (Netherlands)

    Boks, N.P.; Kaper, H.J.; Norde, W.; Busscher, H.J.; Mei, van der H.C.

    2008-01-01

    Adhesion and desorption are simultaneous events during bacterial adhesion to surfaces. although desorption is far less studied than adhesion. Here, desorption of Staphylococcus epidermidis from substratum surfaces is demonstrated to be residence time dependent. Initial desorption rate coefficients

  5. Competitive Sorption and Desorption of Chlorinated Organic Solvents (DNAPLs) in Engineered Natural Organic Matter

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Jixin; Weber, Walter J., Jr.

    2004-03-31

    The effects of artificially accelerated geochemical condensation and maturation of natural organic matter on the sorption and desorption of trichloroethylene (TCE) and tetrachloroethylene (PCE) were studied. The sorption and desorption of TCE in the presence and absence of the competing PCE and 1,2-dichlorobenzene (DCB) were also examined. A sphagnum peat comprising geologically young organic matter was artificially ''aged'' using superheated water, thus increasing the aromaticity and the degree of condensation of its associated organic matter. The sorption of all solutes tested were increased remarkably and their respective desorptions reduced, by the aged peat. The sorption capacities and isotherm nonlinearities of the peat for both TCE and PCE were found to increase as treatment temperature increased. In the competitive sorption studies, both PCE and DCB were found to depress TCE sorption, with PCE having greater effects than DCB, presumably because the molecular structure o f the former is more similar to that of TCE.

  6. Study of CeO₂ Modified AlNi Mixed Pillared Clays Supported Palladium Catalysts for Benzene Adsorption/Desorption-Catalytic Combustion.

    Science.gov (United States)

    Li, Jingrong; Zuo, Shufeng; Yang, Peng; Qi, Chenze

    2017-08-15

    A new functional AlNi-pillared clays (AlNi-PILC) with a large surface area and pore volume was synthesized. The performance of adsorption/desorption-catalytic combustion over CeO 2- modified Pd/AlNi-PILC catalysts was also studied. The results showed that the d 001 -value and specific surface area ( S BET ) of AlNi-PILC reached 2.11 nm and 374.8 m²/g, respectively. The large S BET and the d 001 -value improved the high capacity for benzene adsorption. Also, the strong interaction between PdCe mixed oxides and AlNi-PILC led to the high dispersion of PdO and CeO₂ on the support, which was responsible for the high catalytic performance. Especially, 0.2% Pd/12.5% Ce/AlNi-PILC presented high performance for benzene combustion at 240 °C and high CO₂ selectivity. Also, the combustion temperatures were lower compared to the desorption temperatures, which demonstrated that it could accomplish benzene combustion during the desorption process. Furthermore, its activity did not decrease after continuous reaction for 1000 h in dry air, and it also displayed good resistance to water and the chlorinated compound, making it a promising catalytic material for the elimination of volatile organic compounds.

  7. The function of advanced treatment process in a drinking water treatment plant with organic matter-polluted source water.

    Science.gov (United States)

    Lin, Huirong; Zhang, Shuting; Zhang, Shenghua; Lin, Wenfang; Yu, Xin

    2017-04-01

    To understand the relationship between chemical and microbial treatment at each treatment step, as well as the relationship between microbial community structure in biofilms in biofilters and their ecological functions, a drinking water plant with severe organic matter-polluted source water was investigated. The bacterial community dynamics of two drinking water supply systems (traditional and advanced treatment processes) in this plant were studied from the source to the product water. Analysis by 454 pyrosequencing was conducted to characterize the bacterial diversity in each step of the treatment processes. The bacterial communities in these two treatment processes were highly diverse. Proteobacteria, which mainly consisted of beta-proteobacteria, was the dominant phylum. The two treatment processes used in the plant could effectively remove organic pollutants and microbial polution, especially the advanced treatment process. Significant differences in the detection of the major groups were observed in the product water samples in the treatment processes. The treatment processes, particularly the biological pretreatment and O 3 -biological activated carbon in the advanced treatment process, highly influenced the microbial community composition and the water quality. Some opportunistic pathogens were found in the water. Nitrogen-relative microorganisms found in the biofilm of filters may perform an important function on the microbial community composition and water quality improvement.

  8. Recent advances in thermal desorption-gas chromatography-mass spectrometery method to eliminate the matrix effect between air and water samples: application to the accurate determination of Henry's law constant.

    Science.gov (United States)

    Kim, Yong-Hyun; Kim, Ki-Hyun

    2014-05-16

    Accurate values for the Henry's law constants are essential to describe the environmental dynamics of a solute, but substantial errors are recognized in many reported data due to practical difficulties in measuring solubility and/or vapor pressure. Despite such awareness, validation of experimental approaches has scarcely been made. An experimental approach based on thermal desorption-gas chromatography-mass spectrometery (TD-GC-MS) method was developed to concurrently allow the accurate determination of target compounds from the headspace and aqueous samples in closed equilibrated system. The analysis of six aromatics and eight non-aromatic oxygenates was then carried out in a static headspace mode. An estimation of the potential bias and mass balance (i.e., sum of mass measured individually from gas and liquid phases vs. the mass initially added to the system) demonstrates compound-specific phase dependency so that the best results are obtained by aqueous (less soluble aromatics) and headspace analysis (more soluble non-aromatics). Accordingly, we were able to point to the possible sources of biases in previous studies and provide the best estimates for the Henry's constants (Matm(-1)): benzene (0.17), toluene (0.15), p-xylene (0.13), m-xylene (0.13), o-xylene (0.19), styrene (0.27); propionaldehyde (9.26), butyraldehyde (6.19), isovaleraldehyde (2.14), n-valeraldehyde (3.98), methyl ethyl ketone (10.5), methyl isobutyl ketone (3.93), n-butyl acetate (2.41), and isobutyl alcohol (22.2). Copyright © 2014 Elsevier B.V. All rights reserved.

  9. Water Reuse in Industrial food Processing. | Pagella | Journal of ...

    African Journals Online (AJOL)

    While water, as an industrial commodity, is considered increasingly as a valuable material and the subject of responsible care for the environment, water ... show how remarkable environmental and economic advantages can be simply obtained by implementing low investment cost solutions, and that water supply and ...

  10. A comparative life cycle assessment of process water treatment ...

    African Journals Online (AJOL)

    The increasingly poor quality of South Africafs natural water sources requires industries and power stations to treat raw water extensively prior to industrial use in, for example, boilers. Two different raw water desalination technologies, an existing ion exchange plant and a proposed reverse osmosis intervention, are ...

  11. Development of regulations for water care works and process ...

    African Journals Online (AJOL)

    driniev

    and controlled in a sustainable and equitable manner, for the benefit of all persons and in accordance with its constitutional .... training happen. The proposed regulation. Water care works. Schedules I and II deal with the classification of Water Care Works which are defined as both potable water and wastewater treatment.

  12. Assessing pesticide leaching and desorption in soils with different agricultural activities from Argentina (Pampa and Patagonia).

    Science.gov (United States)

    Gonzalez, Mariana; Miglioranza, Karina S B; Aizpún, Julia E; Isla, Federico I; Peña, Aránzazu

    2010-09-01

    Pesticide distribution in the soil profile depends on soil and pesticide properties as well as on the composition of irrigation water. Water containing surfactants, acids or solvents, may alter pesticide desorption from soil. The distribution of organochlorine pesticides (OCPs) in two Argentinean agricultural areas, Pampa and Patagonia, was evaluated. Furthermore, pesticide desorption from aged and freshly spiked soils was performed by the batch technique, using solutions of sodium oxalate and citrate, dissolved organic carbon (DOC), wastewater and surfactants. Patagonian soil showed the highest OCP levels (46.5-38.1 μg g(-1) OC) from 0 to 30 cm depth and the predominance of p,p'-DDE residues reflected an extensive and past use of DDT. Pampean soil with lower levels (0.039-0.07 μg g(-1) OC) was mainly polluted by the currently used insecticide endosulfan. Sodium citrate and oxalate, at levels usually exuded by plant roots, effectively enhanced desorption of p,p'-DDT, p,p'-DDE and α-cypermethrin, while no effects were observed for α-endosulfan and endosulfan sulfate. The non-ionic surfactant Tween 80 behaved similarly to the acids, whereas the anionic sodium dodecyl sulfate enhanced desorption of all pesticides. Increased desorption of the hydrophobic pesticides also occurred when DOC from humic acids but not from sewage sludge or wastewater were used. Soil profile distribution of pesticides was in accordance with results from desorption studies. Data suggest pesticide leaching in Pampean and Patagonian soils, with risk of endosulfan to reach groundwater and that some organic components of wastewaters may enhance the solubilisation and leaching of recalcitrant compounds such as p,p'-DDT and p,p'-DDE. Copyright © 2010 Elsevier Ltd. All rights reserved.

  13. Reactive Desorption of CO Hydrogenation Products under Cold Pre-stellar Core Conditions

    Science.gov (United States)

    Chuang, K.-J.; Fedoseev, G.; Qasim, D.; Ioppolo, S.; van Dishoeck, E. F.; Linnartz, H.

    2018-02-01

    The astronomical gas-phase detection of simple species and small organic molecules in cold pre-stellar cores, with abundances as high as ∼10‑8–10‑9 n H, contradicts the generally accepted idea that at 10 K, such species should be fully frozen out on grain surfaces. A physical or chemical mechanism that results in a net transfer from solid-state species into the gas phase offers a possible explanation. Reactive desorption, i.e., desorption following the exothermic formation of a species, is one of the options that has been proposed. In astronomical models, the fraction of molecules desorbed through this process is handled as a free parameter, as experimental studies quantifying the impact of exothermicity on desorption efficiencies are largely lacking. In this work, we present a detailed laboratory study with the goal of deriving an upper limit for the reactive desorption efficiency of species involved in the CO–H2CO–CH3OH solid-state hydrogenation reaction chain. The limit for the overall reactive desorption fraction is derived by precisely investigating the solid-state elemental carbon budget, using reflection absorption infrared spectroscopy and the calibrated solid-state band-strength values for CO, H2CO and CH3OH. We find that for temperatures in the range of 10 to 14 K, an upper limit of 0.24 ± 0.02 for the overall elemental carbon loss upon CO conversion into CH3OH. This corresponds with an effective reaction desorption fraction of ≤0.07 per hydrogenation step, or ≤0.02 per H-atom induced reaction, assuming that H-atom addition and abstraction reactions equally contribute to the overall reactive desorption fraction along the hydrogenation sequence. The astronomical relevance of this finding is discussed.

  14. Sequential adaptation of Nannochloropsis gaditana to table olive processing water.

    Science.gov (United States)

    Serrano, Antonio; Contreras, Carmen; Ruiz-Filippi, Gonzalo; Borja, Rafael; Fermoso, Fernando G

    2017-08-24

    The main objective of this study was to evaluate the suitability of Nannochloropsis gaditana to grow by sequential adaptation to TOPW (Table olive processing water) at increased substrate concentrations (10-80%). Sequential adaptation allows growing Nannochloropsis gaditana up to 80% TOPW, although the maximum microalgae biomass productions were achieved for percentages of 20-40%, i.e. 0.308 ± 0.005 g VSS (Volatile Suspended Solids)/L. In all growth experiments, proteins were the majority compound in the grown microalgae biomass (0.44 ± 0.05 g/g VSS), whereas phenols were retained up to a mean concentration of 12.1 ± 1.9 mg total phenols/g VSS. The highest microalgae biomass production rate at rate of 80% TOPW took place in the first two days when most nutrients were also removed. Average removal efficiencies at this percentage of TOPW were 69.1%, 50.9%, 54.3% and 71.8% for total organic carbon, total soluble nitrogen, phosphate and total phenols, respectively. Sequential adaptation can ensure the obtaining of a sustainable microalgae culture as a treatment method for TOPW.

  15. EPA Region 7 and Four States Water Quality Standards Review Process Kaizen Event

    Science.gov (United States)

    The submittal, review and approval process of the EPA–State process for developing and revising Water Quality Standards (WQS) was the focus of a Lean business process improvement kaizen event in June 2007.

  16. 3rd International Workshop on Desorption Induced by Electronic Transitions

    CERN Document Server

    Knotek, Michael

    1988-01-01

    These proceedings are the result of the third international workshop on Desorption Induced by Electronic Transitions, DIET III, which took place on Shelter Island, NY, May. 20-22, 1987. The work contained in this volume is an excellent summary of the current status of the field and should be a valuable reference text for both "seasoned" researchers and newcomers in the field of DIET. Based on the success of the meeting it seems clear that interest and enthusiasm in the field is strong. It is also apparent, from the many lively discussions during the meeting, that many unanswered questions (and controversies) remain to be solved. It was particularly pleasing to see many new participants from new and rapidly advancing fields, ranging from gas phase dynamics to semiconductor processing. The resulting cross-fertilization from these separate but related fields is playing an important role in helping us understand desorption processes at solid surfaces. In general, the topics covered during the course of the worksh...

  17. 5th International Workshop on Desorption Induced by Electronic Transitions

    CERN Document Server

    Jennison, Dwight R; Stechel, Ellen B; DIET V; Desorption induced by electronic transitions

    1993-01-01

    This volume in the Springer Series on Surface Sciences presents a recent account of advances in the ever-broadening field of electron-and photon-stimulated sur­ face processes. As in previous volumes, these advances are presented as the proceedings of the International Workshop on Desorption Induced by Electronic Transitions; the fifth workshop (DIET V) was held in Taos, New Mexico, April 1-4, 1992. It will be abundantly clear to the reader that "DIET" is not restricted to desorption, but has for several years included photochemistry, non-thermal surface modification, exciton self-trapping, and many other phenomena that are induced by electron or photon bombardment. However, most stimulated surface processes do share a common physics: initial electronic excitation, localization of the excitation, and conversion of electronic energy into nuclear kinetic energy. It is the rich variation of this theme which makes the field so interesting and fruitful. We have divided the book into eleven parts in orde...

  18. Integrated processes for produced water polishing: Enhanced flotation/sedimentation combined with advanced oxidation processes.

    Science.gov (United States)

    Jiménez, Silvia; Micó, María M; Arnaldos, Marina; Ferrero, Enrique; Malfeito, Jorge J; Medina, Francisco; Contreras, Sandra

    2017-02-01

    In this study, bench scale dissolved air flotation (DAF) and settling processes have been studied and compared to a novel flotation technology based on the use of glass microspheres of limited buoyancy and its combination with conventional DAF, (Enhanced DAF or E-DAF). They were evaluated as pretreatments for advanced oxidation processes (AOPs) to polish produced water (PW) for reuse purposes. Settling and E-DAF without air injection showed adequate turbidity and oil and grease (O&G) removals, with eliminations higher than 87% and 90% respectively, employing 70 mg L(-1) of FeCl3 and 83 min of settling time, and 57.9 mg L(-1) of FeCl3, 300 mg L(-1) of microspheres and a flocculation rate of 40 rpm in the E-DAF process. A linear correlation was observed between final O&G concentration and turbidity after E-DAF. In order to polish the O&G content of the effluent even further, to remove soluble compounds as phenol and to take advantage of residual iron after these treatments, Fenton and photo-Fenton reactions were essayed. After 6 h of the Fenton reaction at pH 3, the addition of 1660 mg L(-1) of H2O2 and 133 mg L(-1) of iron showed a maximum O&G elimination of 57.6% and a phenol removal up to 80%. Photo-Fenton process showed better results after 3 h, adding 600 mg L(-1) of H2O2 and 300 mg L(-1) of iron, at pH 3, with a higher fraction of elimination of the O&G content (73.7%) and phenol (95%) compared to the conventional Fenton process. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Investigation of the instability and low water kefir grain growth during an industrial water kefir fermentation process.

    Science.gov (United States)

    Laureys, David; Van Jean, Amandine; Dumont, Jean; De Vuyst, Luc

    2017-04-01

    A poorly performing industrial water kefir production process consisting of a first fermentation process, a rest period at low temperature, and a second fermentation process was characterized to elucidate the causes of its low water kefir grain growth and instability. The frozen-stored water kefir grain inoculum was thawed and reactivated during three consecutive prefermentations before the water kefir production process was started. Freezing and thawing damaged the water kefir grains irreversibly, as their structure did not restore during the prefermentations nor the production process. The viable counts of the lactic acid bacteria and yeasts on the water kefir grains and in the liquors were as expected, whereas those of the acetic acid bacteria were high, due to the aerobic fermentation conditions. Nevertheless, the fermentations progressed slowly, which was caused by excessive substrate concentrations resulting in a high osmotic stress. Lactobacillus nagelii, Lactobacillus paracasei, Lactobacillus hilgardii, Leuconostoc mesenteroides, Bifidobacterium aquikefiri, Gluconobacter roseus/oxydans, Gluconobacter cerinus, Saccharomyces cerevisiae, and Zygotorulaspora florentina were the most prevalent microorganisms. Lb. hilgardii, the microorganism thought to be responsible for water kefir grain growth, was not found culture-dependently, which could explain the low water kefir grain growth of this industrial process.

  20. Boiling water neutronic reactor incorporating a process inherent safety design

    Science.gov (United States)

    Forsberg, C.W.

    1985-02-19

    A boiling-water reactor core is positioned within a prestressed concrete reactor vessel of a size which will hold a supply of coolant water sufficient to submerge and cool the reactor core by boiling for a period of at least one week after shutdown. Separate volumes of hot, clean (nonborated) water for cooling during normal operation and cool highly borated water for emergency cooling and reactor shutdown are separated by an insulated wall during normal reactor operation with contact between the two water volumes being maintained at interfaces near the top and bottom ends of the reactor vessel. Means are provided for balancing the pressure of the two water volumes at the lower interface zone during normal operation to prevent entry of the cool borated water into the reactor core region, for detecting the onset of excessive power to coolant flow conditions in the reactor core and for detecting low water levels of reactor coolant. Cool borated water is permitted to flow into the reactor core when low reactor coolant levels or excessive power to coolant flow conditions are encountered.

  1. 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.

  2. A comparative life cycle assessment of process water treatment ...

    African Journals Online (AJOL)

    2011-07-29

    Jul 29, 2011 ... activities however lead to dissipative losses of vast volumes of freshwater for cooling purposes, which give rise to sus- tainability concerns, given that the catchment areas in which many of these industries were built are relatively water scarce. (Rogers et al., 2008). In response to these water constraints,.

  3. changing waterscapes under water reform processes in rural ...

    African Journals Online (AJOL)

    This paper contributes to the ongoing discussion on the implementation of water reforms in rural African waterscapes and explores how farmers in a tertiary catchment in Zimbabwe react to these reforms. It shows how privileged farmers have jumped the water queue by moving their agricultural activities upstream where ...

  4. Separation of Process Water using Hydroxy Sodalite Membranes

    NARCIS (Netherlands)

    Khajavi, S.

    2010-01-01

    This thesis describes the synthesis, characterization, and application of Hydroxy Sodalite (H-SOD) membranes in selective separation of water from aqueous solutions and reaction media. The emphasis has been put on the development of a tight membrane film that could be primarily used for water

  5. Water Consumption Estimates of the Biodiesel Process in the US

    Science.gov (United States)

    As a renewable alternative to petroleum diesel, biodiesel has been widely used in the US and around the world. Along with the rapid development of the biodiesel industry, its potential impact on water resources should also be evaluated. This study investigates water consumption f...

  6. A comparative life cycle assessment of process water treatment ...

    African Journals Online (AJOL)

    2011-07-29

    Jul 29, 2011 ... softening and hot lime softening. Hot lime softening (HLS) ... filtration. Raw water. Condensate make up to boilers. Condensate. Make Up. Tank. Brines and Sludge management. Treatment chemicals. Electricity. Emmissions ... Feed water is dosed at 5 mg/ℓ with chlorine gas (0.15 kg/Mℓ. BFW), and sodium ...

  7. Evaluation of pretreatment processes for supercritical water oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Barnes, C.M.

    1994-01-01

    This report evaluates processes to chemically treat US Department of Energy wastes to remove organic halogens, phosphorus, and sulfur. Chemical equilibrium calculations, process simulations, and responses from developers and licensors form the basis for comparisons. Gas-phase catalytic hydrogenation processes, strong base and base catalyzed processes, high pressure hydrolysis, and other emerging or commercial dehalogenation processes (both liquid and mixed phase) were considered. Cost estimates for full-scale processes and demonstration testing are given. Based on the evaluation, testing of a hydrogenation process and a strong base process are recommended.

  8. Characterizing natural organic matter in drinking water treatment processes and trains

    NARCIS (Netherlands)

    Baghoth, S.A.

    2012-01-01

    Natural organic matter (NOM) generally influences water treatment processes such as coagulation, oxidation, adsorption, and membrane filtration. NOM contributes colour, taste and odour in drinking water, fouls membranes, serves as a precursor for disinfection by-products, increases the exhaustion

  9. Characterization of Adsorption Enthalpy of Novel Water-Stable Zeolites and Metal-Organic Frameworks

    Science.gov (United States)

    Kim, Hyunho; Cho, H. Jeremy; Narayanan, Shankar; Yang, Sungwoo; Furukawa, Hiroyasu; Schiffres, Scott; Li, Xiansen; Zhang, Yue-Biao; Jiang, Juncong; Yaghi, Omar M.; Wang, Evelyn N.

    2016-01-01

    Water adsorption is becoming increasingly important for many applications including thermal energy storage, desalination, and water harvesting. To develop such applications, it is essential to understand both adsorbent-adsorbate and adsorbate-adsorbate interactions, and also the energy required for adsorption/desorption processes of porous material-adsorbate systems, such as zeolites and metal-organic frameworks (MOFs). In this study, we present a technique to characterize the enthalpy of adsorption/desorption of zeolites and MOF-801 with water as an adsorbate by conducting desorption experiments with conventional differential scanning calorimetry (DSC) and thermogravimetric analyzer (TGA). With this method, the enthalpies of adsorption of previously uncharacterized adsorbents were estimated as a function of both uptake and temperature. Our characterizations indicate that the adsorption enthalpies of type I zeolites can increase to greater than twice the latent heat whereas adsorption enthalpies of MOF-801 are nearly constant for a wide range of vapor uptakes.

  10. Kinetics of tetracycline, oxytetracycline, and chlortetracycline adsorption and desorption on two acid soils

    DEFF Research Database (Denmark)

    Fernandez Calviño, David; Bermúdez-Couso, Alipio; Arias-Estévez, Manuel

    2015-01-01

    The purpose of this work was to quantify retention/release of tetracycline, oxytetracycline, and chlortetracycline on two soils, paying attention to sorption kinetics and to implications of the adsorption/desorption processes on transfer of these pollutants to the various environmental compartments....... We used the stirred flow chamber (SFC) procedure to achieve this goal. All three antibiotics showed high affinity for both soils, with greater adsorption intensity for soil 1, the one with the highest organic matter and Al and Fe oxides contents. Desorption was always ... on soils and other media, thus increasing knowledge on the behavior and evolution of these pharmaceutical residues in the environment....

  11. Adsorption-desorption kinetics and chemical potential of adsorbed and gas-phase particles

    Science.gov (United States)

    Zhdanov, V. P.

    2001-03-01

    In the literature, one can find two alternative ways of using the chemical potential of adsorbed and gas-phase particles, μa and μg, for describing the adsorption-desorption kinetics. According to the first approach, the desorption rate depends only on μa. The second approach, proposed by Ward et al. in a series of papers published in the Journal of Chemical Physics, predicts that the desorption rate is proportional to exp[(μa-μg)/kBT]. Scrutinizing the formalism used by Ward et al., we show that the latter dependence makes no sense because it contradicts the basic principles of the general theory of activated rate processes.

  12. Electron stimulated desorption of anions and cations from condensed allyl glycidyl ether.

    Science.gov (United States)

    Yildirim, Y; Balcan, M; Bass, A D; Cloutier, P; Sanche, L

    2010-07-28

    We report measurements of the electron stimulated desorption (ESD) of anions and cations from thin films of allyl glycidyl ether (AGE), formed by condensation onto multilayer Kr and Pt substrates using a high sensitivity time of flight mass analyser. Measurements were performed as a function of film thickness, incident electron energy (E(i)) and effective incident current. Below incident electron energies of 20 eV the desorption of anions is dominated by the process of dissociative electron attachment (DEA) via several transient negative ions at E(i) between 5.5 and 16.5 eV. Comparisons between measurements for AGE and ethyl oxirane show that the ESD of anions is essentially that of the glycidyl (epoxide) ring, though DEA occurring at the ether, within the linear part of the AGE molecule is also observed. Cation yields are dominated by the desorption of small fragments formed via scission of the same ether bond.

  13. Coupling biophysical processes and water rights to simulate spatially distributed water use in an intensively managed hydrologic system

    Directory of Open Access Journals (Sweden)

    B. Han

    2017-07-01

    Full Text Available Humans have significantly altered the redistribution of water in intensively managed hydrologic systems, shifting the spatiotemporal patterns of surface water. Evaluating water availability requires integration of hydrologic processes and associated human influences. In this study, we summarize the development and evaluation of an extensible hydrologic model that explicitly integrates water rights to spatially distribute irrigation waters in a semi-arid agricultural region in the western US, using the Envision integrated modeling platform. The model captures both human and biophysical systems, particularly the diversion of water from the Boise River, which is the main water source that supports irrigated agriculture in this region. In agricultural areas, water demand is estimated as a function of crop type and local environmental conditions. Surface water to meet crop demand is diverted from the stream reaches, constrained by the amount of water available in the stream, the water-rights-appropriated amount, and the priority dates associated with particular places of use. Results, measured by flow rates at gaged stream and canal locations within the study area, suggest that the impacts of irrigation activities on the magnitude and timing of flows through this intensively managed system are well captured. The multi-year averaged diverted water from the Boise River matches observations well, reflecting the appropriation of water according to the water rights database. Because of the spatially explicit implementation of surface water diversion, the model can help diagnose places and times where water resources are likely insufficient to meet agricultural water demands, and inform future water management decisions.

  14. Water in the Mendoza, Argentina, food processing industry: water requirements and reuse potential of industrial effluents in agriculture

    Directory of Open Access Journals (Sweden)

    Alicia Elena Duek

    2016-04-01

    Full Text Available This paper estimates the volume of water used by the Mendoza food processing industry considering different water efficiency scenarios. The potential for using food processing industry effluents for irrigation is also assessed. The methodology relies upon information collected from interviews with qualified informants from different organizations and food-processing plants in Mendoza selected from a targeted sample. Scenarios were developed using local and international secondary information sources. The results show that food processing plants in Mendoza use 19.65 hm3 of water per year; efficient water management practices would make it possible to reduce water use by 64%, i.e., to 7.11 hm3. At present, 70% of the water is used by the fruit and vegetable processing industry, 16% by wineries, 8% by mineral water bottling plants, and the remaining 6% by olive oil, beer and soft drink plants. The volume of effluents from the food processing plants in Mendoza has been estimated at 16.27 hm3 per year. Despite the seasonal variations of these effluents, and the high sodium concentration and electrical conductivity of some of them, it is possible to use them for irrigation purposes. However, because of these variables and their environmental impact, land treatment is required.

  15. Desorption isotherms, drying characteristics and qualities of glace tropical fruits undergoing forced convection solar drying

    Energy Technology Data Exchange (ETDEWEB)

    Jamradloedluk, Jindaporn; Wiriyaumpaiwong, Songchai [Mahasarakham Univ. Khamriang, Kantarawichai, Mahasarakham (Thailand)

    2008-07-01

    Solar energy, a form of sustainable energy, has a great potential for a wide variety of applications because it is abundant and accessible, especially for countries located in the tropical region. Drying process is one of the prominent techniques for utilization of solar energy. This research work proposes a forced convection solar drying of osmotically pretreated fruits viz. mango, guava, and pineapple. The fruit cubes with a dimension of 1cm x 1cm x 1cm were immersed in 35% w./w. sucrose solution prior to the drying process. Drying kinetics, color and hardness of the final products obtained from solar drying were investigated and compared with those obtained from open air-sun drying. Desorption isotherms of the osmosed fruits were also examined and five mathematical models were used to fit the desorption curves. Experimental results revealed that solar drying provided higher drying rate than natural sun drying. Color of glace fruit processed by solar drying was more intense, indicated by lower value of lightness and higher value of yellowness, than that processed by sun drying. Hardness of the products dehydrated by both drying methods, however, was not significantly different (p>0.05). Validation of the mathematical models developed showed that the GAB model was most effective for describing desorption isotherms of osmotically pretreated mango and pineapple whereas Peleg's model was most effective for describing desorption isotherms of osmotically pretreated guava. (orig.)

  16. Desorption of H atoms from graphite (0001) using XUV free electron laser pulses

    DEFF Research Database (Denmark)

    Siemer, B.; Olsen, Thomas; Hoger, T.

    2010-01-01

    , and identifies the highest vibrational state in the adsorbate potential as a major source for the slow atoms. It is evident that multiple electron scattering processes are required for this desorption. A direct electronic excitation of a repulsive hydrogen-carbon bond seems not to be important....

  17. Frontal analysis for characterizing the adsorption-desorption behavior of beta-lactoglobulin on immunoadsorbents.

    Science.gov (United States)

    Puerta, Angel; Vidal-Madjar, Claire; Jaulmes, Alain; Diez-Masa, Jose-Carlos; de Frutos, Mercedes

    2006-06-30

    High-performance frontal affinity chromatography was employed to study the adsorption-desorption kinetics characterizing the retention of beta-lactoglobulin (beta-LG) onto polyclonal anti-beta-lactoglobulin (anti-beta-LG) chromatographic supports. The adsorption and desorption processes were studied by analyzing two different elution fronts separated by a relatively long rinsing step. The method consists in performing two successive frontal injections of the protein. In between, the column was rinsed with a given volume of mobile phase (buffer alone). During this rinsing stage, a partial desorption may occur and a novel amount of protein could be adsorbed in the second frontal injection step. The whole process (first adsorption, possible desorption, and second adsorption) was simulated by a numerical procedure, in which the column was divided into a large number of slices. A model based on bi-Langmuir type kinetics was used to describe the adsorption of the protein on the support. The model assumes a non-uniform adsorbent with two types of binding sites. At equilibrium the adsorption isotherm is of the bi-Langmuir type. A global adsorption effect was considered which includes the effective binding process and the mass transfer resistances due to the transport to the binding site. Therefore, the column capacity and the kinetic parameters of the model (apparent adsorption and desorption rate constants) were determined from the best fit of the first and second adsorption fronts to the experimental ones. The other parameters of the model are the saturation capacities for the adsorption on each type of sites. The equilibrium affinity constants were estimated in a single experiment from the ratio of the apparent adsorption and desorption rate constants. The high values found (around 10(8) M(-1)) reveal a strong interaction of beta-LG with the immunoadsorbent. Kinetic measurements were carried out at different flow rates. Both the apparent adsorption and desorption

  18. Process for treating effluent from a supercritical water oxidation reactor

    Science.gov (United States)

    Barnes, Charles M.; Shapiro, Carolyn

    1997-01-01

    A method for treating a gaseous effluent from a supercritical water oxidation reactor containing entrained solids is provided comprising the steps of expanding the gas/solids effluent from a first to a second lower pressure at a temperature at which no liquid condenses; separating the solids from the gas effluent; neutralizing the effluent to remove any acid gases; condensing the effluent; and retaining the purified effluent to the supercritical water oxidation reactor.

  19. Influence of salinity and water regime on tomato for processing

    Directory of Open Access Journals (Sweden)

    Vito Cantore

    2012-03-01

    Full Text Available The effects of salinity and watering regime on tomato crop are reported. The trials have been carried out over two years in Southern Italy on a deep loam soil. Three saline levels of irrigation water (with electrical conductivity of 0.5, 5 and 10 dS m-1, three watering regimes (at 20, 40 and 60% of available water depletion, and two cultivars (HLY19 and Perfectpeel were compared. The overall results related to the salinity tolerance are in agreement with those from the literature indicating that water salinity reduced marketable yield by 55% in respect to the control treatments. The irrigation regimes that provided higher total and marketable yield were at 40 and 60% of available water depletion (on average, 90.5 and 58.1 Mg ha-1 against 85.3 and 55.5 Mg ha-1 of the 20% available water depletion. Saline and irrigation treatments did not affect sunburned fruits, while affected incidence of fruits with blossom-end rot. The former disease appeared more dramatically in saline treatments (+28% in respect to the control, and occurred mainly in HLY19. The disease incidence was by 52% lower in W2 respect to the W1 and W3. Fruit firmness was higher in S0, whereas it was not affected by irrigation regimes. Total soluble solids and dry matter content of tomato fruits were increased by salinity, whereas it was not affected by irrigation regimes and cultivars. The pH and the titratable acidity remained unchanged between the years, the cultivar and the saline and irrigation treatments. Similarly to the last parameters, the fruit ascorbic acid content remained unchanged in relation to the treatments, but it was higher in HLY19. The recommended thresholds of easily available water to preserve total and marketable yield were at 40 and 60%, respectively. Watering more frequently, instead, on the soil type of the trial, probably caused water-logging and root hypoxia affecting negatively yield.

  20. Evaluating the impact of an ammonia-based post-combustion CO2 capture process on a steam power plant with different cooling water temperatures

    DEFF Research Database (Denmark)

    Linnenberg, Sebastian; Darde, Victor Camille Alfred; Oexmann, Jochen

    2012-01-01

    The use of aqueous ammonia is a promising option to capture carbon dioxide from the flue gas of coal-fired power plants. Compared to a capture process using monoethanolamine (MEA), the use of ammonia can reduce the heat requirement of the CO2 desorption significantly, although an additional effor...

  1. Intended process water management concept for the mechanical biological treatment of municipal solid waste

    Directory of Open Access Journals (Sweden)

    D. Weichgrebe

    2008-03-01

    Full Text Available Accumulating operational experience in both aerobic and anaerobic mechanical biological waste treatment (MBT makes it increasingly obvious that controlled water management would substantially reduce the cost of MBT and also enhance resource recovery of the organic and inorganic fraction. The MBT plant at Gescher, Germany, is used as an example in order to determine the quantity and composition of process water and leachates from intensive and subsequent rotting, pressing water from anaerobic digestion and scrubber water from acid exhaust air treatment, and hence prepare an MBT water balance. The potential of, requirements for and limits to internal process water reuse as well as the possibilities of resource recovery from scrubber water are also examined. Finally, an assimilated process water management concept with the purpose of an extensive reduction of wastewater quantity and freshwater demand is presented.

  2. Starch hydrolysis under low water conditions: a conceptual process design

    NARCIS (Netherlands)

    Veen, van der M.E.; Veelaert, S.; Goot, van der A.J.; Boom, R.M.

    2006-01-01

    A process concept is presented for the hydrolysis of starch to glucose in highly concentrated systems. Depending on the moisture content, the process consists of two or three stages. The two-stage process comprises combined thermal and enzymatic liquefaction, followed by enzymatic saccharification.

  3. Feasibility of desorption atmospheric pressure photoionization and desorption electrospray ionization mass spectrometry to monitor urinary steroid metabolites during pregnancy.

    Science.gov (United States)

    Vaikkinen, Anu; Rejšek, Jan; Vrkoslav, Vladimír; Kauppila, Tiina J; Cvačka, Josef; Kostiainen, Risto

    2015-06-23

    Steroids have important roles in the progress of pregnancy, and their study in maternal urine is a non-invasive method to monitor the steroid metabolome and its possible abnormalities. However, the current screening techniques of choice, namely immunoassays and gas and liquid chromatography-mass spectrometry, do not offer means for the rapid and non-targeted multi-analyte studies of large sample sets. In this study, we explore the feasibility of two ambient mass spectrometry methods in steroid fingerprinting. Urine samples from pregnant women were screened by desorption electrospray ionization (DESI) and desorption atmospheric pressure photoionization (DAPPI) Orbitrap high resolution mass spectrometry (HRMS). The urine samples were processed by solid phase extraction for the DESI measurements and by enzymatic hydrolysis and liquid-liquid-extraction for DAPPI. Consequently, steroid glucuronides and sulfates were detected by negative ion mode DESI-HRMS, and free steroids by positive ion mode DAPPI-HRMS. In DESI, signals of eleven steroid metabolite ions were found to increase as the pregnancy proceeded, and in DAPPI ten steroid ions showed at least an order of magnitude increase during pregnancy. In DESI, the increase was seen for ions corresponding to C18 and C21 steroid glucuronides, while DAPPI detected increased excretion of C19 and C21 steroids. Thus both techniques show promise for the steroid marker screening in pregnancy. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. [Arsenic (V) removal from drinking water by ferric salt and aluminum salt coagulation/microfiltration process].

    Science.gov (United States)

    Li, Xiao-bo; Wu, Shui-bo; Gu, Ping

    2007-10-01

    Two lab-scale coagulation/microfiltration membrane reactors were used to compare the arsenic removal from drinking water by ferric salt and aluminum salt coagulation/microfiltration process. FeCl3 and Al2(SO4)3 were appointed as the coagulants. The results show that the arsenic removal efficiency of the two processes are almost equal. Arsenic concentration can be lowered from about 100 microg/L to below 10 microg/L and the lowest is 1.68 microg x L(-1). All of the turbidity of the treated water is less than 0.1 NTU. The concentrations of ferric, aluminum and SO4(2-) of the treated water are entirely satisfied the standard of drinking water. After treated by ferric salt process, pH value of the treated water is increased about 0.5. However, aluminum salt process does not change pH of the drinking water. The concentration ratio of the ferric salt process is 1,791 which is about 2.54 times of the aluminum salt process. Arsenic concentration of the sludge of ferric salt process is also higher greatly than that of the aluminum salt process. Therefore, the volume of the sludge produced by the ferric salt process is smaller than that of the aluminum salt process when equal amount of drinking water was treated. Accordingly, ferric salt process should be used when only high concentration arsenic existed in drinking water. On the other hand, fluoride also can be removed simultaneously while arsenic was removed by aluminum salt process. The amount of coagulant needed is the amount of coagulant required to remove fluoride separately. Fluoride can not be removed from drinking water by the ferric salt process. It was concluded that aluminum salt process should be used to remove arsenic and fluoride simultaneously from high arsenic and high fluoride coexisted drinking water.

  5. Bacterial community structure in the drinking water microbiome is governed by filtration processes.

    Science.gov (United States)

    Pinto, Ameet J; Xi, Chuanwu; Raskin, Lutgarde

    2012-08-21

    The bacterial community structure of a drinking water microbiome was characterized over three seasons using 16S rRNA gene based pyrosequencing of samples obtained from source water (a mix of a groundwater and a surface water), different points in a drinking water plant operated to treat this source water, and in the associated drinking water distribution system. Even though the source water was shown to seed the drinking water microbiome, treatment process operations limit the source water's influence on the distribution system bacterial community. Rather, in this plant, filtration by dual media rapid sand filters played a primary role in shaping the distribution system bacterial community over seasonal time scales as the filters harbored a stable bacterial community that seeded the water treatment processes past filtration. Bacterial taxa that colonized the filter and sloughed off in the filter effluent were able to persist in the distribution system despite disinfection of finished water by chloramination and filter backwashing with chloraminated backwash water. Thus, filter colonization presents a possible ecological survival strategy for bacterial communities in drinking water systems, which presents an opportunity to control the drinking water microbiome by manipulating the filter microbial community. Grouping bacterial taxa based on their association with the filter helped to elucidate relationships between the abundance of bacterial groups and water quality parameters and showed that pH was the strongest regulator of the bacterial community in the sampled drinking water system.

  6. Process and utility water requirements for cellulosic ethanol production processes via fermentation pathway

    Science.gov (United States)

    The increasing need of additional water resources for energy production is a growing concern for future economic development. In technology development for ethanol production from cellulosic feedstocks, a detailed assessment of the quantity and quality of water required, and the ...

  7. Adsorptive water removal from dichloromethane and vapor-phase regeneration of a molecular sieve 3A packed bed

    OpenAIRE

    Jovic, S Slavisa; Laxminarayan, Y; Keurentjes, JTF Jos; Schouten, JC Jaap; Schaaf, van der, S.

    2017-01-01

    The drying of dichloromethane with a molecular sieve 3A packed bed process is modeled and experimentally verified. In the process, the dichloromethane is dried in the liquid phase and the adsorbent is regenerated by water desorption with dried dichloromethane product in the vapor phase. Adsorption equilibrium experiments show that dichloromethane does not compete with water adsorption, because of size exclusion; the pure water vapor isotherm from literature provides an accurate representation...

  8. Computational Analysis of Sedimentation Process in the Water Treatment Plant

    Science.gov (United States)

    Tulus; Suriati; Situmorang, M.; Zain, D. M.

    2017-09-01

    This study aims to determine how the distribution of sludge concentration and velocity of water flow in the water treatment plant in equilibrium state. The problems are solved by implementing the finite element method to a momentum transport equation which is a basic differential equation that is used for liquid-solid mixtures with high solid concentrations. In the finite element method, the flow field is broken down into a set of smaller fluid elements. The domain is considered as a container in the space of three-dimensional (3D). The sludge concentration distribution as well as the water flow velocity distribution in the inlet, central and outlet are different. The results of numerical computation are similar compared to the measurement results.

  9. Surface coverage effects on the desorption kinetics of selenite from a hydroxyaluminum-montmorillonite complex.

    Science.gov (United States)

    Saha, U K; Huang, P M

    2010-10-01

    Information on the desorption of metals and metalloids from soils and clays are essential for a better understanding of their mobility, transport, and fate in natural environments. We investigated nitrate-, phosphate-, and citrate-induced desorption kinetics of preadsorbed selenite (presented as Se henceforth) from a hydroxyaluminum-montmorillonite (HyA-Mt) complex at three different surface coverages of 8%, 25%, and 69% of its Langmuir predicted adsorption maximum (262.61 mmole kg(-1)). Generally the mole fraction of preadsorbed Se released after the attainment of desorption equilibrium was significantly higher with increasing surface coverage. Desorption kinetics of Se from the clay was best described by the Elovich model. The Elovich model parameter beta representing the rate of Se desorption increased as the surface coverage increased. Both kinetic data and mole fraction of Se released at desorption equilibrium supported the contention that adsorption bond strength progressively decreases with increasing surface coverage. Both citrate and phosphate remobilized Se at significantly faster rates than nitrate at any surface coverage level. Citrate showed a significantly faster rate of Se release than phosphate only at 8% surface coverage but not at 25% and 69% surface coverages, suggesting that differential ability of these two ligands to influence the kinetics of Se release was also surface coverage dependent. The findings of the present study would help better understand the consequences of different surface coverages on soil colloids by preadsorbed Se as well as the impacts of phosphate fertilization and rhizospheric processes in influencing Se mobility in soil and related environments. Copyright 2010 Elsevier Inc. All rights reserved.

  10. Performance of a Water Recirculation Loop Maintenance Device and Process for the Advanced Spacesuit Water Membrane Evaporator

    Science.gov (United States)

    Rector, Tony; Steele, John W.; Bue, Grant C.; Campbell, Colin; Makinen, Janice

    2012-01-01

    A water loop maintenance device and process to maintain the water quality of the Advanced Spacesuit Water Membrane Evaporation (SWME) water recirculation loop has been undergoing a performance evaluation. The SWME is a heat rejection device under development at the NASA Johnson Space Center to perform thermal control for advanced spacesuits. One advantage to this technology is the potential for a significantly greater degree of tolerance to contamination when compared to the existing Sublimator technology. The driver for the water recirculation maintenance device and process is to further enhance this advantage through the leveraging of fluid loop management lessons-learned from the International Space Station (ISS). A bed design that was developed for a Hamilton Sundstrand military application, and considered for a potential ISS application with the Urine Processor Assembly, provides a low pressure drop means for water maintenance in a recirculation loop. The bed design is coupled with high capacity ion exchange resins, organic adsorbents, and a cyclic methodology developed for the Extravehicular Mobility Unit (EMU) Transport Water loop. The maintenance process further leverages a sorbent developed for ISS that introduces a biocide in a microgravity-compatible manner for the Internal Active Thermal Control System (IATCS). The leveraging of these water maintenance technologies to the SWME recirculation loop is a unique demonstration of applying the valuable lessons learned on the ISS to the next generation of manned spaceflight Environmental Control and Life Support System (ECLSS) hardware. This

  11. HYDROGEN AND ITS DESORPTION IN RHIC.

    Energy Technology Data Exchange (ETDEWEB)

    HSEUH,H.C.

    2002-11-11

    Hydrogen is the dominating gas specie in room temperature, ultrahigh vacuum systems of particle accelerators and storage rings, such as the Relativistic Heavy Ion Collider (RHIC) at Brookhaven. Rapid pressure increase of a few decades in hydrogen and other residual gases was observed during RHIC's recent high intensity gold and proton runs. The type and magnitude of the pressure increase were analyzed and compared with vacuum conditioning, beam intensity, number of bunches and bunch spacing. Most of these pressure increases were found to be consistent with those induced by beam loss and/or electron stimulated desorption from electron multipacting.

  12. Environmental life cycle assessments for water treatment processes ...

    African Journals Online (AJOL)

    The objective of this study was to generate information on the environmental profile of the life cycle of water, including treatment, distribution and collection and disposal (including recycling), in an urban context. As a case study the eThekwini Municipality (with its main city Durban) in South Africa was used. Another aim of ...

  13. 20171130_Ind Ergo Report_631 DI Water Movement Process.

    Energy Technology Data Exchange (ETDEWEB)

    Rivera, Cynthia R. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-11-30

    Perform an industrial ergonomic assessment to evaluate the new procedures for filling, lifting, and delivering high purity de-ionized water to building 9925. The goal was to improve on the previous method by minimizing/eliminating as much lifting and bending as possible to reduce the potential for overexertion-related injuries.

  14. Nickel (II) ion desorption kinetic modeling from unmodified and ...

    African Journals Online (AJOL)

    The desorption of Ni2+ from three oil palm fruit fibre adsorbents (UOPF, 0.5MOPF and 1.0MOPF) using five desorbing solutions showed a desorption efficiency following the trend, 0.1M HCl > 0.1MH2SO4 > 0.1MHNO3 > 0.1MNaOH >hot deionized H2O. The Elovich desorption constant, β values for the 0.1MHCl desorbent ...

  15. Policies lost in translation? Unravelling water reform processes in African waterscapes

    NARCIS (Netherlands)

    Kemerink-Seyoum, J.S.

    2015-01-01

    Since the 1980s a major change took place in public policies for water resources management. The role of governments shifted under this reform process from an emphasis on investment in the development, operation and maintenance of water infrastructure to a focus on managing water resources systems

  16. Food selectivity and processing by the cold-water Coral Lophelia pertusa

    NARCIS (Netherlands)

    van Oevelen, Dick; Mueller, Christina E.; Lundälv, Tomas; Middelburg, Jack J.

    2016-01-01

    Cold-water corals form prominent reef ecosystems along ocean margins that depend on suspended resources produced in surface waters. In this study, we investigated food processing of 13C and 15N labelled bacteria and algae by the cold-water coral Lophelia pertusa. Coral respiration, tissue

  17. Deep water overflow in the Faroe Bank Channel; modelling, processes, and impact

    DEFF Research Database (Denmark)

    Rullyanto, Arief

    2015-01-01

    or tides, but also deep beneath the surface, where deep-water currents circulate waters throughout the world’s oceans. In certain very-localized regions, the flow of the deep-water has to travel over a sill in a narrow submarine channel. This overflow process mixes the deep water with overlying waters......, creating new water masses with distinct temperature, salinity and density characteristics. The change of water mass characteristics not only affects the local environment, but also far distant regions. The Faroe Bank Channel, which is located in the southern part of Faroe Islands, is one of the most...... important overflow regions in the world. It connects two huge ocean basins, the North Atlantic Ocean and the Nordic Seas, and the water mass produced there is an important ingredient of North Atlantic Deep Water, a water mass that found very nearly everywhere in the deep basins of the world’s oceans...

  18. Hydrochemical processes in mine waste deposits and drainage water - Heavy metal speciation, sorption and sedimentation processes

    Energy Technology Data Exchange (ETDEWEB)

    Loevgren, L.; Sjoeberg, S. [Umeaa Univ. (Sweden). Dept. of Inorganic Chemistry

    1997-12-31

    The aim of the present project has been to quantitatively describe hydrochemical processes relevant for the retention and mobility of heavy metals in mine waste deposits. The activities have been focused on the solubility and speciation of Pb(II), Cd(II), Cu(II), Zn(II), CR(VI) and As(III,V). Main attention has been paid to adsorption processes at the surfaces of iron (hydr)oxides (goethite, et-FeOOH). The main experimental methods for studying the adsorption reactions have been potentiometric titrations and batch adsorption experiments. Experimental data have been evaluated in terms of models for surface complexation equilibria, which can be used in hydrogeochemical model calculations of processes within the deposits as well as in the recipients of drainage water. Furthermore, in several cases the surface complexes formed have been characterized structurally by means of Fourier Transform-Infrared spectroscopy. In order to test the validity of the equilibrium models obtained at millimolar concentrations of both sorbate and sorbent a new method utilizing Anodic Stripping Voltammetry as an in situ probe in titrations has been developed within the project. A particular interest has been given to the influence of complexing inorganic and organic anions on the adsorption of the heavy metal ions. The presence of sulfate ions resulted in a moderate increased adsorption of Cu(II) and Pb(II) under acidic conditions, while the adsorption of Zn(II) remained uninfluenced. The increased adsorption could be explained by reduced electrostatic repulsion between positively charged surfaces and metal ions, and by formation of ternary surface complexes. Similar mechanisms could explain the data in the goethite-Me(II)- carboxylate systems. The organic acids study are: phthalic acid, trimellitic acid and pyromellitic acid, which are aromatic acids with two, three and four carboxylate groups, respectively. Before the experimental data in the organic containing systems could be

  19. Water Transfer Characteristics during Methane Hydrate Formation Processes in Layered Media

    Directory of Open Access Journals (Sweden)

    Yousheng Deng

    2011-08-01

    Full Text Available Gas hydrate formation processes in porous media are always accompanied by water transfer. To study the transfer characteristics comprehensively, two kinds of layered media consisting of coarse sand and loess were used to form methane hydrate in them. An apparatus with three PF-meter sensors detecting water content and temperature changes in media during the formation processes was applied to study the water transfer characteristics. It was experimentally observed that the hydrate formation configurations in different layered media were similar; however, the water transfer characteristics and water conversion ratios were different.

  20. Substrate-Enhanced Micro Laser Desorption Ionization Mass Spectrometry Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Aerodyne Research, Inc. and the University of Massachusetts at Amherst will collaborate to develop laser desorption ionization (LDI) mass spectrometric analysis of...

  1. Effect of the ionic status and drying on radiocesium adsorption and desorption in organic soils

    Energy Technology Data Exchange (ETDEWEB)

    Rigol, A.; Vidal, M.; Rauret, G.

    1999-11-01

    Radiocesium (RCs) interaction in organic soils has been studied using adsorption and desorption experiments, and the effects of the ionic status and drying were evaluated. Four organic soils were used: three peaty podzols containing illite and a peat without illitic materials, RCs solid-liquid distribution coefficients (K{sub D}) were determined for each soil in water and in several solutions containing Ca, K, or a mixture of the two. RCs contamination was performed either with a single equilibration or after a three-step preequilibration. Whereas the ionic strength of the solution controlled RCs adsorption in the peat, the level of monovalent species was the most important factor in RCs adsorption in the peaty podzols. Reversibility of RCs adsorbed in the different conditions was assessed in the moist sample and after drying by single and consecutive extractions with either CaCl{sub 2} or CH{sub 3}COONH{sub 4}. RCs adsorption was totally reversible in the peat regardless of the ionic status and the desorption approach used. For the three peaty podzols, due to the presence of specific sites, adsorption reversibility was dependent on the scenario in which this adsorption was performed and on the cation used in desorption. Finally, although NH{sub 4} is known to desorb RCs specifically adsorbed in the soil, it was shown to induce interlayer collapse, and consecutive extractions with CaCl{sub 2} led to higher desorption yields.

  2. Clinoptilolite in study of lindane and aldrin sorption processes from water solution.

    Science.gov (United States)

    Sprynskyy, Myroslav; Ligor, Tomasz; Buszewski, Bogusław

    2008-03-01

    The scope of this study was adsorption of lindane and aldrin from water solution onto clinoptilolite rock with the following desorption using n-hexane. Both kinetic and equilibrium tests were conducted. During kinetic experiment the most part of aldrin and a half part of lindane were sorbed during the first hours. The sorption equilibria with removal of 95% of aldrin amount and about 68% of lindane amount have been set in for 48 h. The pseudo-second-order kinetics model gives somewhat better fit to the both pesticides' sorption data that may testify to the complicated and heterogeneous nature of interaction between active zeolite surface and the pesticides polar-dipole centers. OH(-)-groups and the coordinated exchangeable cations are probably the main active positions for the pesticide sorption on the clinoptilolite surface. Equilibrium experiment results show that adsorption isotherms for the low concentrations of lindane and aldrin (10-200 and 3-100 microg/L, respectively) fit well to the Freundlich and the Liner models. Only 10% of lindane sorbed and about 60% of aldrin sorbed were desorbed from the clinoptilolite using n-hexane under static conditions.

  3. The use of process simulation models in virtual commissioning of process automation software in drinking water treatment plants

    NARCIS (Netherlands)

    Worm, G.I.M.; Kelderman, J.P.; Lapikas, T.; Van der Helm, A.W.C.; Van Schagen, K.M.; Rietveld, L.C.

    2012-01-01

    This research deals with the contribution of process simulation models to the factory acceptance test (FAT) of process automation (PA) software of drinking water treatment plants. Two test teams tested the same piece of modified PA-software. One team used an advanced virtual commissioning (AVC)

  4. Resupply mechanism to a contaminated aquifer: A laboratory study of U(VI) desorption from capillary fringe sediments

    Science.gov (United States)

    Um, Wooyong; Zachara, John M.; Liu, Chongxuan; Moore, Dean A.; Rod, Kenton A.

    2010-09-01

    Contaminated capillary fringe sediments are believed to function as long-term source of U(VI) to Hanford's 300 Area groundwater uranium plume that discharges to the Columbia River. The deep vadose zone at this site experiences seasonal water table elevation and water compositional changes in response to Columbia River stage. Batch and column desorption experiments of U(VI) were performed on two mildly contaminated sediments from this system that vary in hydrologic position to ascertain their U(VI) release behavior and factors controlling it. Solid phase characterization of the sediments was performed to identify mineralogic and chemical factors controlling U(VI) desorption. Low adsorbed U(VI) concentrations prevented spectroscopic analysis. The desorption behavior of U(VI) was different for the two sediments in spite of similar chemical and textural characteristics, and non-carbonate mineralogy. Adsorption strength and sorbed U(VI) lability was higher in the near-river sediment. The inland sediment displayed low sorbed U(VI) lability (˜10%) and measurable solid-phase carbonate content. Kinetic desorption was observed that was attributed to regeneration of labile U(VI) in the near river sediment, and carbonate mineral dissolution in the inland sediment. The desorption reaction was best described as an equilibrium surface complexation reaction. The noted differences in desorption behavior appear to result from U(VI) contamination and hydrologic history, as well as sediment carbonate content. Insights are provided on the dynamic adsorption/desorption behavior of contaminants in linked groundwater-river systems.

  5. Energy implications of water reduction strategies in Kraft process : part 2 : results

    Energy Technology Data Exchange (ETDEWEB)

    Mateos-Espejel, E.; Marinova, M.; Barapour, S.; Paris, J. [Ecole Polytechnique, Montreal, PQ (Canada). Dept. de Genie Chimique

    2010-05-15

    This article discussed the results obtained using a methodology for determining optimal water reduction strategies in a kraft pulp mill. The methodology used a 5-step procedure to analyze water utilization, benchmark consumption rates, identify restrictions, and assess the implications of water closure on heat recovery processes. This case study evaluated 4 potential strategies for simultaneous reductions in water, steam, and cooling requirements. Strategies included: (1) the reuse of condensates from the evaporators, (2) the reuse of whitewater, (3) the reuse of bleaching filtrate, and (4) the use of vacuum pumps to seal water. A trade-off analysis compared the strategies with results obtained using an optimized heat exchanger network. Results of the study showed that the proposed water reduction strategies saved 24 per cent of total water, 14 MW of steam, and 13.1 MW of cooling demand. Results demonstrated that water closure strategies must form a central part of process energy optimization projects. 9 refs., 1 tab., 7 figs.

  6. Process for the production of furfural from pentoses and/or water soluble pentosans

    NARCIS (Netherlands)

    De Jong, W.; Marcotullio, G.

    2012-01-01

    The invention is directed to a process for the production of furfural from pentoses and/or water soluble pentosans, said process comprising converting the said pentoses and/or water soluble pentosans in aqueous solution in a first step to furfural and in a second step feeding the aqueous solution

  7. 76 FR 71008 - Yuba County Water Agency; Notice of Dispute Resolution Process Schedule; Panel Meeting, and...

    Science.gov (United States)

    2011-11-16

    ... Energy Regulatory Commission Yuba County Water Agency; Notice of Dispute Resolution Process Schedule... resolution process, pursuant to 18 CFR 5.14, in the relicensing proceeding for the Yuba County Water Agency's (YCWA) Yuba River Hydroelectric Project No. 2246. NMFS disputes the treatment of several of its study...

  8. Biomass composition of Arthrospira platensis during cultivation on industrial process water and harvesting

    DEFF Research Database (Denmark)

    Ljubic, Anita; Safafar, Hamed; Holdt, Susan Løvstad

    2017-01-01

    out in four different concentrations of industrial process water (25, 50, 75, and 100%). The biomass was then harvested by microfiltration, and centrifugation followed by freeze drying. Variations in biomass composition were studied, in order to investigate effects of industrial process water on A...

  9. Multicausal analysis on water deterioration processes present in a drinking water treatment system.

    Science.gov (United States)

    Wang, Li; Ma, Fang; Pang, Changlong; Firdoz, Shaik

    2013-03-01

    The fluctuation of water turbidity has been studied during summer in the settling tanks of a drinking water treatment plant. Results from the multiple cause-effect model indicated that five main pathways interactively influenced thequalityof tank water. During rain, turbidity levels increased mainly as a result of decreasing pH and anaerobic reactions (partial effect = 68%). Increasing water temperature combined with dissolved oxygen concentration (partial effect = 64%) was the key parameterforcontrolling decreases in water turbidity during nighttime periods after a rainy day. The dominant factor influencing increases in turbidity during sunny daytime periods was algal blooms (partial effect = 86%). However, short-circuiting waves (partial effect = 77%) was the main cause for increased nighttime water turbidity after a sunny day. The trade offbetween regulatory pathways was responsible for environmental changes, and the outcome was determined by the comparative strengths of each pathway.

  10. Electroacoustic Process Study of Plasma Sparker Under Different Water Depth

    KAUST Repository

    Huang, Yifan

    2015-01-05

    The plasma sparker has been applied in oceanic high-resolution seismic exploration for decades. Normally it is towed on the water surface. This is suitable for shallow water, but if the water depth is great, the resolution will decrease dramatically, especially in the horizontal direction. This paper proposes the concept of a deep-towed plasma sparker and presents an experimental study of plasma sparker performance in terms of electric parameters, bubble behavior, and acoustic characteristics. The results show that hydrostatic pressure at a source depth ranging from 1 to 2000 m has a negligible influence on the electric parameters but a strong influence on bubble behavior, wherein both the maximum bubble radius and oscillation period are decreased. The collapse pulse vanishes when the source depth reaches 1000 m or deeper, and no bubble oscillation can be distinguished. The source level (evaluated by the expansion pulse) is also decreased as the source depth increases; moreover, the greater the discharge energy, the smaller the source level loss. The discharge energy per electrode should be greater than 20 J for the deep-towed plasma sparker, which can make the source level loss induced by hydrostatic pressure smaller than the transmission loss. The fast Fourier transform (FFT) results show that the dominant energy is around 20 kHz, which is mainly induced by the expansion pulse and its oscillation. According to the simulation results, the fundamental frequency of the acoustic waveform increases with source depth in accord with a log linear trend, and also reaches tens of kilohertz in deep water. So, before the development of deep-towed plasma sparker, a new technical solution will need to be developed to solve this problem. © 1976-2012 IEEE.

  11. Two-stage desorption-controlled release of fluorescent dye and vitamin from solution-blown and electrospun nanofiber mats containing porogens.

    Science.gov (United States)

    Khansari, S; Duzyer, S; Sinha-Ray, S; Hockenberger, A; Yarin, A L; Pourdeyhimi, B

    2013-12-02

    In the present work, a systematic study of the release kinetics of two embedded model drugs (one completely water soluble and one partially water soluble) from hydrophilic and hydrophobic nanofiber mats was conducted. Fluorescent dye Rhodamine B was used as a model hydrophilic drug in controlled release experiments after it was encapsulated in solution-blown soy-protein-containing hydrophilic nanofibers as well as in electrospun hydrophobic poly(ethylene terephthalate) (PET)-containing nanofibers. Vitamin B2 (riboflavin), a partially water-soluble model drug, was also encapsulated in hydrophobic PET-containing nanofiber mats, and its release kinetics was studied. The nanofiber mats were submerged in water, and the amount of drug released was tracked by fluorescence intensity. It was found that the release process saturates well below 100% release of the embedded compound. This is attributed to the fact that desorption is the limiting process in the release from biopolymer-containing nanofibers similar to the previously reported release from petroleum-derived polymer nanofibers. Release from monolithic as well as core-shell nanofibers was studied in the present work. Moreover, to facilitate the release and ultimately to approach 100% release, we also incorporated porogens, for example, poly(ethylene glycol), PEG. It was also found that the release rate can be controlled by the porogen choice in nanofibers. The effect of nanocracks created by leaching porogens on drug release was studied experimentally and evaluated theoretically, and the physical parameters characterizing the release process were established. The objective of the present work is a detailed experimental and theoretical investigation of controlled drug release from nanofibers facilitated by the presence of porogens. The novelty of this work is in forming nanofibers containing biodegradable and biocompatible soy proteins to facilitate controlled drug release as well as in measuring detailed

  12. Experimental factors controlling analyte ion generation in laser desorption/ionization mass spectrometry on porous silicon.

    Science.gov (United States)

    Kruse, R A; Li, X; Bohn, P W; Sweedler, J V

    2001-08-01

    Desorption/ionization on porous silicon (DIOS) is a relatively new laser desorption/ionization technique for the direct mass spectrometric analysis of a wide variety of samples without the requirement of a matrix. Porous silicon substrates were fabricated using the recently developed nonelectrochemical H2O2-metal-HF etching as a versatile platform for investigating the effects of morphology and physical properties of porous silicon on DIOS-MS performance. In addition, laser wavelength, mode of ion detection, pH, and solvent contributions to the desorption/ionization process were studied. Other porous substrates such as GaAs and GaN, with similar surface characteristics but differing in thermal and optical properties from porous silicon, allowed the roles of surface area, optical absorption, and thermal conductivities in the desorption/ionization process to be investigated. Among the porous semiconductors studied, only porous silicon has the combination of large surface area, optical absorption, and thermal conductivity required for efficient analyte ion generation under the conditions studied. In addition to these substrate-related factors, surface wetting, determined by the interaction of deposition solvent with the surface, and charge state of the peptide were found to be important in determining ion generation efficiency.

  13. Combined water and energy integration in industrial processes with restricted connections

    OpenAIRE

    Kermani, Maziar; Kantor, Ivan Daniel; Maréchal, François

    2016-01-01

    Reducing the environmental impact of industrial processes is highly linked with decreasing consumption of natural resources, energy, and water. In the context of climate change, as discussed during the Conference of Parties in Paris (COP21), the efficient use of energy, water and other resources is one of the solutions to substantially reduce the Greenhouse Gas (GHG) emissions from industry. Industries consume large quantities of energy and water in their processes which are often considered...

  14. Integration of electrically driven membrane separation processes for water treatment and resources recovery

    OpenAIRE

    Reig i Amat, Mònica

    2016-01-01

    Nowadays, due to the growing fresh water demand, several processes are used to purify seawater by means of desalination or industrial brackish water by different treatment processes. The main limitation of these techniques is the production of rejected brines. For this reason, new management techniques for brines valorization are being studied to achieve the maximum water recovery, avoid liquid streams disposal and recover the valuable compounds from the concentrated streams. In this thesis, ...

  15. Ionization Mechanism of Matrix-Assisted Laser Desorption/Ionization

    Science.gov (United States)

    Lu, I.-Chung; Lee, Chuping; Lee, Yuan-Tseh; Ni, Chi-Kung

    2015-07-01

    In past studies, mistakes in determining the ionization mechanism in matrix-assisted laser desorption/ionization (MALDI) were made because an inappropriate ion-to-neutral ratio was used. The ion-to-neutral ratio of the analyte differs substantially from that of the matrix in MALDI. However, these ratios were not carefully distinguished in previous studies. We begin by describing the properties of ion-to-neutral ratios and reviews early experimental measurements. A discussion of the errors committed in previous theoretical studies and a comparison of recent experimental measurements follow. We then describe a thermal proton transfer model and demonstrate how the model appropriately describes ion-to-neutral ratios and the total ion intensity. Arguments raised to challenge thermal ionization are then discussed. We demonstrate how none of the arguments are valid before concluding that thermal proton transfer must play a crucial role in the ionization process of MALDI.

  16. Removal of Mycobacterium avium subspecies hominissuis (MAH) from drinking water by coagulation, flocculation and sedimentation processes.

    Science.gov (United States)

    Wong, E A; Shin, G-A

    2015-03-01

    There has been a growing concern over human exposure to Mycobacterium avium subspecies hominissuis (MAH) through drinking water due to its ubiquitous presence in natural waters and remarkable resistance to both chemical and physical disinfectants in drinking water treatment processes. However, little is known about the effectiveness of physico-chemical water treatment processes to remove MAH. Therefore, we determined the removal of MAH by alum coagulation, flocculation and sedimentation processes in optimized drinking water treatment conditions using standard jar test equipment. Contrary to the prevailing hypothesis, the results of this study show that removal of MAH by coagulation, flocculation and sedimentation processes was only moderate (approx. 0.65 log10) under low turbidity treatment conditions and the removal of MAH was actually lower than that of Escherichia coli (reference bacterium) in all the waters tested. Overall, the results of this study suggested that coagulation, flocculation and sedimentation processes may not be a reliable treatment option for removing MAH, and more efforts to find an effective control measures against MAH should be made to reduce the risk of MAH infection from drinking water. Despite a growing concern over human exposure to Mycobacterium avium subspecies hominissuis (MAH) through drinking water and its remarkable resistance to water disinfectants, little is known about the effectiveness of physico-chemical water treatment processes to remove MAH. Contrary to the prevailing hypothesis, the results of this study suggest that coagulation, flocculation and sedimentation processes may not be a reliable treatment option for MAH removal. As these processes have been the last remaining conventional drinking water treatment processes that might be effective against MAH, more efforts should be urgently made to find an effective control measures against this important waterborne pathogen. © 2014 The Society for Applied Microbiology.

  17. Plasma Desorption Mass Spectrometry analysis of HCOOH ice

    Energy Technology Data Exchange (ETDEWEB)

    Andrade, D.P.P.; Rocco, M.L.M. [Departamento de Fisico-Quimica, Instituto de Quimica, Universidade Federal do Rio de Janeiro, Cidade Universitaria, Ilha do Fundao, 21949-900 Rio de Janeiro, RJ (Brazil); Boechat-Roberty, H.M. [Observatorio do Valongo, Universidade Federal do Rio de Janeiro, Ladeira Pedro Antonio, 43, Centro, Rio de Janeiro, RJ (Brazil); Iza, P.; Martinez, R. [Departamento de Fisica, Pontificia Universidade Catolica do Rio de Janeiro, 22543-900 Rio de Janeiro (Brazil); Homem, M.G.P. [Laboratorio Nacional de Luz Sincrotron (LNLS), Box 6192, 13084-971 Campinas, SP (Brazil); Silveira, E.F. da [Departamento de Fisica, Pontificia Universidade Catolica do Rio de Janeiro, 22543-900 Rio de Janeiro (Brazil)], E-mail: enio@vdg.fis.puc-rio.br

    2007-03-15

    Planetary magnetospheres, in which outer planet satellites orbit, are bombarded by energetic particles inducing chemical and physical changes in their icy surfaces. The existing condensed gases react to form new products, which then undergo thermal evolution from the natural day/night cycles of these satellites. Plasma irradiation of ice causes phase changes, e.g., water ice from crystalline to amorphous over short timescales. When ice is recrystallized by heating, the surface layers retain some disorder, which promote reactions among adsorbed molecules such as H{sub 2}O, CO{sub 2}, CH{sub 2}CO, HCOOH and theirs radiolysis products. In this work, chemical reactions involving formic acid condensed at 56 K are analyzed by using Plasma Desorption Mass Spectrometry-time-of-flight ({sup 252}Cf-PDMS-TOF). Mass spectra of positive and negative desorbed ions were obtained, giving information on the structure and abundance of the molecules on the ice; the expected cations and anions generated by the HCOOH dissociation have been observed. Furthermore, several series of cluster ions were also detected, all exhibiting the structure X{sub n}Y{sub m}R{sup {+-}}, where X and Y are the neutral ice molecules, such as HCOOH or H{sub 2}O, and R{sup {+-}} is either an atomic or a molecular ion, such as H{sup +}, H{sub 3}O{sup +} or COOH{sup -}. In general, the desorption yields of the observed positive and negative ions are characterized by a decreasing exponential function as the emitted ion mass increases; however, the (HCOOH){sub n}OH{sup -} series presents its maximum at n = 8.

  18. Effects of electrolyzed oxidizing water on reducing Listeria monocytogenes contamination on seafood processing surfaces.

    Science.gov (United States)

    Liu, Chengchu; Duan, Jingyun; Su, Yi-Cheng

    2006-02-15

    The effects of electrolyzed oxidizing (EO) water on reducing Listeria monocytogenes contamination on seafood processing surfaces were studied. Chips (5 x 5 cm(2)) of stainless steel sheet (SS), ceramic tile (CT), and floor tile (FT) with and without crabmeat residue on the surface were inoculated with L. monocytogenes and soaked in tap or EO water for 5 min. Viable cells of L. monocytogenes were detected on all chip surfaces with or without crabmeat residue after being held at room temperature for 1 h. Soaking contaminated chips in tap water resulted in small-degree reductions of the organism (0.40-0.66 log cfu/chip on clean surfaces and 0.78-1.33 log cfu/chip on dirty surfaces). Treatments of EO water significantly (peffectiveness of EO water on inactivating Listeria cells. However, treatments of EO water also resulted in significant reductions of L. monocytogenes on dirty surfaces (2.33 log on SS and CT and 1.52 log on FT) when compared with tap water treatments. The antimicrobial activity of EO water was positively correlated with its chlorine content. High oxidation-reduction potential (ORP) of EO water also contributed significantly to its antimicrobial activity against L. monocytogenes. EO water was more effective than chlorine water on inactivating L. monocytogenes on surfaces and could be used as a chlorine alternative for sanitation purpose. Application of EO water following a thorough cleaning process could greatly reduce L. monocytogenes contamination in seafood processing environments.

  19. Experimental Process Identification for Industrial Water De-carbonization in Power Plants

    Directory of Open Access Journals (Sweden)

    MSc. Lutfi Bina

    2013-12-01

    Full Text Available Water Treatment Plant (or WTP is the most important part of the Power Plant, because it produces vital-water it needs for steam production. Power Plants are the biggest air, ground and groundwater pollutants. Bad water quality directly impacts machine duration. Polluted water from Water Treatment Plant has a negative effect on people, flora and fauna, thus better waste management programs should be put in place to eliminate this problem.  In this paper we are going to present the de-carbonization process of raw water as a part of water treatment plant, within coal fired power plants. De-carbonizing water is a time consuming process. We are going to present an advanced method for process identification with big time delay. The results are compared and one of the most appropriate methods is selected as identification method for this process. Further research and possibilities in this area are going to be presented by the end of the paper. Progress in identifying the process by which we work in this paper may serve as a new way to identify highly nonlinear processes. The used algorithm for identification of the process that is outlined in this paper can be applied, and it will be the basis for the creation of the software for the application of microcomputer techniques. Here we are applying the relevant software which can be applied in the form of programming packages for identification. This has to do with passive identification methods.

  20. Removal of Stabilized Silver Nanoparticles from Ohio River Water by Potable Water Treatment Processes

    Science.gov (United States)

    Due to their extensive use, silver nanoparticles (Ag NPs) are likely to occur in drinking water sources. Once released into the environment they are considered an emerging contaminant in water and wastewater. The main objective of this research is to investigate the removal of di...

  1. Unit process engineering for water quality control and biosecurity in marine water recirculating systems

    Science.gov (United States)

    High-intensity systems that treat and recirculate water must maintain a culture environment that can sustain near optimum fish health and growth at the design carrying capacity. Water recirculating systems that use centralized treatment systems can benefit from the economies of scale to decrease th...

  2. Molecular dynamics investigation of desorption and ion separation following picosecond infrared laser (PIRL) ablation of an ionic aqueous protein solution.

    Science.gov (United States)

    Zou, J; Wu, C; Robertson, W D; Zhigilei, L V; Miller, R J D

    2016-11-28

    Molecular dynamics simulations were performed to characterize the ablation process induced by a picosecond infrared laser (PIRL) operating in the regime of desorption by impulsive vibrational excitation (DIVE) of a model peptide (lysozyme)/counter-ion system in aqueous solution. The simulations were performed for ablation under typical experimental conditions found within a time-of-flight mass spectrometer (TOF-MS), that is in vacuum with an applied electric field (E = ± 10(7) V/m), for up to 2 ns post-ablation and compared to the standard PIRL-DIVE ablation condition (E = 0 V/m). Further, a simulation of ablation under an extreme field condition (E = 10(10) V/m) was performed for comparison to extend the effective dynamic range of the effect of the field on charge separation. The results show that the plume dynamics were retained under a typical TOF-MS condition within the first 1 ns of ablation. Efficient desorption was observed with more than 90% of water molecules interacting with lysozyme stripped off within 1 ns post-ablation. The processes of ablation and desolvation of analytes were shown to be independent of the applied electric field and thus decoupled from the ion separation process. Unlike under the extreme field conditions, the electric field inside a typical TOF-MS was shown to modify the ions' motion over a longer time and in a soft manner with no enhancement to fragmentation observed as compared to the standard PIRL-DIVE. The study indicates that the PIRL-DIVE ablation mechanism could be used as a new, intrinsically versatile, and highly sensitive ion source for quantitative mass spectrometry.

  3. Molecular dynamics investigation of desorption and ion separation following picosecond infrared laser (PIRL) ablation of an ionic aqueous protein solution

    Science.gov (United States)

    Zou, J.; Wu, C.; Robertson, W. D.; Zhigilei, L. V.; Miller, R. J. D.

    2016-11-01

    Molecular dynamics simulations were performed to characterize the ablation process induced by a picosecond infrared laser (PIRL) operating in the regime of desorption by impulsive vibrational excitation (DIVE) of a model peptide (lysozyme)/counter-ion system in aqueous solution. The simulations were performed for ablation under typical experimental conditions found within a time-of-flight mass spectrometer (TOF-MS), that is in vacuum with an applied electric field (E = ± 107 V/m), for up to 2 ns post-ablation and compared to the standard PIRL-DIVE ablation condition (E = 0 V/m). Further, a simulation of ablation under an extreme field condition (E = 1010 V/m) was performed for comparison to extend the effective dynamic range of the effect of the field on charge separation. The results show that the plume dynamics were retained under a typical TOF-MS condition within the first 1 ns of ablation. Efficient desorption was observed with more than 90% of water molecules interacting with lysozyme stripped off within 1 ns post-ablation. The processes of ablation and desolvation of analytes were shown to be independent of the applied electric field and thus decoupled from the ion separation process. Unlike under the extreme field conditions, the electric field inside a typical TOF-MS was shown to modify the ions' motion over a longer time and in a soft manner with no enhancement to fragmentation observed as compared to the standard PIRL-DIVE. The study indicates that the PIRL-DIVE ablation mechanism could be used as a new, intrinsically versatile, and highly sensitive ion source for quantitative mass spectrometry.

  4. Approach for predicting P sorption/desorption behaviour of potentially eroded topsoil in watercourses

    Czech Academy of Sciences Publication Activity Database

    Borovec, Jakub; Jan, Jiří

    2018-01-01

    Roč. 624, May (2018), s. 1316-1324 ISSN 0048-9697 R&D Projects: GA TA ČR TA04021342; GA MZe QI102A265; GA MŠk(CZ) EF16_013/0001782 Institutional support: RVO:60077344 Keywords : erosion * Mehlich 3 * sorption/desorption Subject RIV: DJ - Water Pollution ; Quality Impact factor: 4.900, year: 2016

  5. EUTROPHICATION OF WATER RESERVOIRS AND ROLE OF MACROPHYTES IN THIS PROCESS

    OpenAIRE

    Joanna Jadwiga Sender; Cyprian Jaruga

    2017-01-01

    The paper presents the problem related with the process of eutrophication, with special emphasis on dam reservoirs. Eutrophication is a global process, threatening the water ecosystem on every continent. It often leads to their degradation. Particularly vulnerable to eutrophication are artificial reservoirs which are dam reservoirs. This paper describes the mechanisms of eutrophication. We also pointed to the importance of aquatic plants in the process of water purification, as well as the po...

  6. Ab Initio Density Functional Theory Investigation of the Interaction between Carbon Nanotubes and Water Molecules during Water Desalination Process

    Directory of Open Access Journals (Sweden)

    Loay A. Elalfy

    2013-01-01

    Full Text Available Density functional theory calculations using B3LYP/3-21G level of theory have been implemented on 6 carbon nanotubes (CNTs structures (3 zigzag and 3 armchair CNTs to study the energetics of the reverse osmosis during water desalination process. Calculations of the band gap, interaction energy, highest occupied molecular orbital, lowest unoccupied molecular orbital, electronegativity, hardness, and pressure of the system are discussed. The calculations showed that the water molecule that exists inside the CNT is about 2-3 Å away from its wall. The calculations have proven that the zigzag CNTs are more efficient for reverse osmosis water desalination process than armchair CNTs as the reverse osmosis process requires pressure of approximately 200 MPa for armchair CNTs, which is consistent with the values used in molecular dynamics simulations, while that needed when using zigzag CNTs was in the order of 60 MPa.

  7. Quantification of unsteady heat transfer and phase changing process inside small icing water droplets.

    Science.gov (United States)

    Jin, Zheyan; Hu, Hui

    2009-05-01

    We report progress made in our recent effort to develop and implement a novel, lifetime-based molecular tagging thermometry (MTT) technique to quantify unsteady heat transfer and phase changing process inside small icing water droplets pertinent to wind turbine icing phenomena. The lifetime-based MTT technique was used to achieve temporally and spatially resolved temperature distribution measurements within small, convectively cooled water droplets to quantify unsteady heat transfer within the small water droplets in the course of convective cooling process. The transient behavior of phase changing process within small icing water droplets was also revealed clearly by using the MTT technique. Such measurements are highly desirable to elucidate underlying physics to improve our understanding about important microphysical phenomena pertinent to ice formation and accreting process as water droplets impinging onto wind turbine blades.

  8. Field desorption mass spectrometry of oligosaccharides

    Science.gov (United States)

    Linscheid, Michael; D'Angona, Jay; Burlingame, Alma L.; Dell, Anne; Ballou, Clinton E.

    1981-01-01

    Field desorption mass spectrometry has been used to analyze carbohydrate polymers with 5 to 14 hexose units without prior derivatization. In all examples, the molecular weight of the oligosaccharide could be determined by means of the abundant quasimolecular ions of the type MNa+, MH+, MNa22+, and MNa33+. Fragmentation at glycosidic linkages was observed in varying extents. The reduced oligosaccharide Man8GlcNAcH2, obtained from IgM [Cohen, R. E. & Ballou, C. E. (1980) Biochemistry 19, 4345-4358], gave quasimolecular ion signals MNa+ at m/z 1544, MH+ at m/z 1522, MNa22+ at m/z 784, and MNa33+ at m/z 530, all corresponding to its assumed molecular weight of 1519.5. Mycobacterial methylmannose polysaccharides with the general structure ManxMeMany-OCH3 [Yamada, H., Cohen, R. E. & Ballou, C. E. (1979) J. Biol. Chem. 254, 1972-1979] were also successfully analyzed. Man1MeMan13-OCH3, the largest homolog, gave the expected signal of the quasimolecular ion MNa+ at m/z 2506. The larger polysaccharides were analyzed by using a KRATOS MS-50 mass spectrometer with a high-field magnet enabling full sensitivity to be maintained up to 3000 atomic mass units. Polysaccharides up to m/z 1978 were analyzed by using a KRATOS MS-9 mass spectrometer operated at 4 Kv. The signal-to-noise ratio, which becomes a serious problem in field desorption mass spectrometry at low accelerating voltages, and the low instrument sensitivity were improved considerably by our use of a method of adding scans with low total ion currents obtained over a longer desorption time. In this way, we obtained complete sequence information on methylmannose polysaccharides up to Man1MeMan9-OCH3(MNa+ at m/z 1802). Analysis of a presumed Man1MeMan7-OCH3, gave a spectrum consistent only with the structure Man2MeMan6-OCH3, revealing the existence of a methylmannose homolog with 2 unmethylated mannoses at the nonreducing end of the chain. PMID:6940169

  9. LC-HRMS Data Processing Strategy for Reliable Sample Comparison Exemplified by the Assessment of Water Treatment Processes.

    Science.gov (United States)

    Bader, Tobias; Schulz, Wolfgang; Kümmerer, Klaus; Winzenbacher, Rudi

    2017-12-19

    The behavior of micropollutants in water treatment is an important aspect in terms of water quality. Nontarget screening by liquid chromatography coupled to high-resolution mass spectrometry (LC-HRMS) offers the opportunity to comprehensively assess water treatment processes by comparing the signal heights of all detectable compounds before and after treatment. Without preselection of known target compounds, all accessible information is used to describe changes across processes and thus serves as a measure for the treatment efficiency. In this study, we introduce a novel LC-HRMS data processing strategy for the reliable classification of signals based on the observed fold changes. An approach for filtering detected features was developed and, after parameter adjustment, validated for its recall and precision. As proof of concept, the fate of 411 target compounds in a 0.1 μg/L standard mix was tracked throughout the data processing stages, where 406 targets were successfully recognized and retained during filtering. Potential pitfalls in signal classification were addressed. We found the recursive peak integration to be a key point for the reliable classification of signal changes across a process. For evaluating the repeatability, a combinatorial approach was conducted to verify the consistency of the final outcome using technical replicates of influent and effluent samples taken from an ozonation process during drinking water treatment. The results showed sufficient repeatability and thus emphasized the applicability of nontarget screening for the assessment of water treatment processes. The developed data processing strategies may be transferred to other research fields where sample comparisons are conducted.

  10. Kinetic desorption of fluoride in a granitic soil column: Experiments and reactive transport modeling

    Science.gov (United States)

    Padhi, S.; Tokunaga, T.

    2016-12-01

    The transport of fluoride or other contaminants in subsurface largely depends on their interaction with mineral surfaces of contact. Hence, the methods to evaluate and predict the extent of these interactions are of great importance. The commonly used distribution coefficient (Kd) model does not account for temporally and spatially variable geochemical conditions (Curtis et al., 2006). This study aims to investigate the reactive transport of fluoride in a natural soil column by laboratory experiments and solute transport modeling by introducing surface complexation of fluoride to the transport simulation. For our purpose, column experiments for fluoride sorption and desorption under saturated conditions were conducted in the laboratory on a granitic soil from Tsukuba, Japan. Stable isotopes of water (δ18O and δ2H) were used as conservative tracers to evaluate the flow and transport properties. Existence of physical and chemical nonequilibrium during fluoride transport was evaluated by applying stop flow events. Long tailing during fluoride desorption was observed, and the linear Kd model failed to explain this phenomenon. Hence, a geochemical model considering fluoride sorption in soil by surface complexation was developed to explain fluoride transport in the column. The intrinsic surface complexation constants for fluoride sorption reactions and surface site protonation and deprotonation reactions were corrected from that of the optimized results from batch experiments based as suggested by Sverjensky (2003). The model with fluoride sorption defined by surface complexation explained the observed fluoride desorption data quite satisfactorily, especially the long tailing. An overshoot in the breakthrough curve observed by the simulation during early period of desorption could be due to competitive desorption, which need to be further analyzed. References: (1) Curtis, JP, Davis, JA, Nafiz, DL 2006. Wat. Res. Res., 42, W04404, doi:10.1029/2005WR003979; (2

  11. Sequential sorption and desorption of chlorinated phenols in organoclays.

    Science.gov (United States)

    Kim, J H; Shin, W S; Kim, Y H; Choi, S J; Jeon, Y W; Song, D I

    2003-01-01

    Effect of pH on the sorption and desorption of the chlorinated phenols (2-chlorophenol and 2,4-dichlorophenol) in HDTMA-montmorillonite organoclays was investigated using sequential batch experiments. 2,4-dichlorophenol exhibited higher affinity in both sorption and desorption than 2-chlorophenol at pH 4.85 and 9.15. For both chlorophenols, the protonated speciation (at pH 4.85) exhibited a higher affinity in both sorption and desorption than the predominant deprotonated speciation (about 80% and 95% of 2-chlorophenate and 2,4-dichlophenate anions at pH 9.15, respectively). Desorption of chlorinated phenols was strongly dependent on the current pH regardless of their speciation during the previous sorption stage. No appreciable desorption resistance of the chlorinated phenols was observed in organoclays after sequential desorptions. Affinity of both chlorophenols in bisolute competitive sorption and desorption was reduced compared to that in a single-solute system due to the competition between solutes. The ideal adsorbed solution theory coupled with the single-solute Freundlich model successfully predicted the bisolute competitive sorption and desorption equilibria.

  12. Modeling Organic Contaminant Desorption from Municipal Solid Waste Components

    Science.gov (United States)

    Knappe, D. R.; Wu, B.; Barlaz, M. A.

    2002-12-01

    Approximately 25% of the sites on the National Priority List (NPL) of Superfund are municipal landfills that accepted hazardous waste. Unlined landfills typically result in groundwater contamination, and priority pollutants such as alkylbenzenes are often present. To select cost-effective risk management alternatives, better information on factors controlling the fate of hydrophobic organic contaminants (HOCs) in landfills is required. The objectives of this study were (1) to investigate the effects of HOC aging time, anaerobic sorbent decomposition, and leachate composition on HOC desorption rates, and (2) to simulate HOC desorption rates from polymers and biopolymer composites with suitable diffusion models. Experiments were conducted with individual components of municipal solid waste (MSW) including polyvinyl chloride (PVC), high-density polyethylene (HDPE), newsprint, office paper, and model food and yard waste (rabbit food). Each of the biopolymer composites (office paper, newsprint, rabbit food) was tested in both fresh and anaerobically decomposed form. To determine the effects of aging on alkylbenzene desorption rates, batch desorption tests were performed after sorbents were exposed to toluene for 30 and 250 days in flame-sealed ampules. Desorption tests showed that alkylbenzene desorption rates varied greatly among MSW components (PVC slowest, fresh rabbit food and newsprint fastest). Furthermore, desorption rates decreased as aging time increased. A single-parameter polymer diffusion model successfully described PVC and HDPE desorption data, but it failed to simulate desorption rate data for biopolymer composites. For biopolymer composites, a three-parameter biphasic polymer diffusion model was employed, which successfully simulated both the initial rapid and the subsequent slow desorption of toluene. Toluene desorption rates from MSW mixtures were predicted for typical MSW compositions in the years 1960 and 1997. For the older MSW mixture, which had a

  13. Kinetic and isothermal adsorption-desorption of PAEs on biochars: effect of biomass feedstock, pyrolysis temperature, and mechanism implication of desorption hysteresis.

    Science.gov (United States)

    Jing, Fanqi; Pan, Minjun; Chen, Jiawei

    2018-02-09

    Biochar has the potential to sequester biomass carbon efficiently into land, simultaneously while improving soil fertility and crop production. Biochar has also attracted attention as a potential sorbent for good performance on adsorption and immobilization of many organic pollutants such as phthalic acid esters (PAEs), a typical plasticizer in plastic and presenting a current environmental issue. Due to lack of investigation on the kinetic and thermodynamic adsorption-desorption of PAEs on biochar, we systematically assessed adsorption-desorption for two typical PAEs, dimethyl phthalate (DMP) and diethyl phthalate (DEP), using biochar derived from peanut hull and wheat straw at different pyrolysis temperatures (450, 550, and 650 °C). The aromaticity and specific surface area of biochars increased with the pyrolysis temperature, whereas the total amount of surface functional groups decreased. The quasi-second-order kinetic model could better describe the adsorption of DMP/DEP, and the adsorption capacity of wheat straw biochars was higher than that of peanut hull biochars, owing to the O-bearing functional groups of organic matter on exposed minerals within the biochars. The thermodynamic analysis showed that DMP/DEP adsorption on biochar is physically spontaneous and endothermic. The isothermal desorption and thermodynamic index of irreversibility indicated that DMP/DEP is stably adsorbed. Sorption of PAEs on biochar and the mechanism of desorption hysteresis provide insights relevant not only to the mitigation of plasticizer mobility but also to inform on the effect of biochar amendment on geochemical behavior of organic pollutants in the water and soil.

  14. Method of manipulating the chemical properties of water to improve the effectiveness of a desired process

    Science.gov (United States)

    Hawthorne, Steven B.; Miller, David J.; Lagadec, Arnaud Jean-Marie; Hammond, Peter James; Clifford, Anthony Alan

    2002-01-01

    The method of the present invention is adapted to manipulate the chemical properties of water in order to improve the effectiveness of a desired process. The method involves heating the water in the vessel to subcritical temperatures between 100.degree. to 374.degree. C. while maintaining sufficient pressure to the water to maintain the water in the liquid state. Various physiochemical properties of the water can be manipulated including polarity, solute solubility, surface tension, viscosity, and the disassociation constant. The method of the present invention has various uses including extracting organics from solids and semisolids such as soil, selectively extracting desired organics from liquids, selectively separating organics using sorbent phases, enhancing reactions by controlling the disassociation constant of water, cleaning waste water, removing organics from water using activated carbon or other suitable sorbents, and degrading various compounds.

  15. Formation process of a strong water-repellent alumina surface by the sol-gel method

    Science.gov (United States)

    Feng, Libang; Li, Hui; Song, Yongfeng; Wang, Yulong

    2010-03-01

    A novel strong water-repellent alumina thin film is fabricated by chemically adsorbing stearic acid (STA) layer onto the porous and roughened aluminum film coated with polyethyleneimine (PEI). The formation process and the structure of the strong water-repellent alumina film are investigated by means of contact angle measurement and atomic force microscope (AFM). Results show that the water contact angles for the alumina films increase with the increase of the immersion time in the boiling water, and meanwhile, the roughness of the alumina films increases with the dissolution of the boehmite in the boiling water. Finally, the strong water-repellent film with a high water contact angle of 139.1° is obtained when the alumina films have distinct roughened morphology with some papillary peaks and porous structure. Moreover, both the roughened structure and the hydrophobic materials of the STA endow the alumina films with the strong water-repellence.

  16. Towards Better Understanding of Pea Seed Dormancy Using Laser Desorption/Ionization Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Monika Cechová

    2017-10-01

    Full Text Available Seed coats of six pea genotypes contrasting in dormancy were studied by laser desorption/ionization mass spectrometry (LDI-MS. Multivariate statistical analysis discriminated dormant and non-dormant seeds in mature dry state. Separation between dormant and non-dormant types was observed despite important markers of particular dormant genotypes differ from each other. Normalized signals of long-chain hydroxylated fatty acids (HLFA in dormant JI64 genotype seed coats were significantly higher than in other genotypes. These compounds seem to be important markers likely influencing JI64 seed imbibition and germination. HLFA importance was supported by study of recombinant inbred lines (JI64xJI92 contrasting in dormancy but similar in other seed properties. Furthemore HLFA distribution in seed coat was studied by mass spectrometry imaging. HLFA contents in strophiole and hilum are significantly lower compared to other parts indicating their role in water uptake. Results from LDI-MS experiments are useful in understanding (physical dormancy (first phases of germination mechanism and properties related to food processing technologies (e.g., seed treatment by cooking.

  17. Operable Unit 7-13/14 in situ thermal desorption treatability study work plan

    Energy Technology Data Exchange (ETDEWEB)

    Shaw, P.; Nickelson, D.; Hyde, R.

    1999-05-01

    This Work Plan provides technical details for conducting a treatability study that will evaluate the application of in situ thermal desorption (ISTD) to landfill waste at the Subsurface Disposal Area (SDA) at the Idaho National Engineering and Environmental Laboratory (INEEL). ISTD is a form of thermally enhanced vapor vacuum extraction that heats contaminated soil and waste underground to raise its temperature and thereby vaporize and destroy most organics. An aboveground vapor vacuum collection and treatment system then destroys or absorbs the remaining organics and vents carbon dioxide and water to the atmosphere. The technology is a byproduct of an advanced oil-well thermal extraction program. The purpose of the ISTD treatability study is to fill performance-based data gaps relative to off-gas system performance, administrative feasibility, effects of the treatment on radioactive contaminants, worker safety during mobilization and demobilization, and effects of landfill type waste on the process (time to remediate, subsidence potential, underground fires, etc.). By performing this treatability study, uncertainties associated with ISTD as a selected remedy will be reduced, providing a better foundation of remedial recommendations and ultimate selection of remedial actions for the SDA.

  18. Integrated field emission array for ion desorption

    Science.gov (United States)

    Resnick, Paul J; Hertz, Kristin L; Holland, Christopher; Chichester, David; Schwoebel, Paul

    2013-09-17

    An integrated field emission array for ion desorption includes an electrically conductive substrate; a dielectric layer lying over the electrically conductive substrate comprising a plurality of laterally separated cavities extending through the dielectric layer; a like plurality of conically-shaped emitter tips on posts, each emitter tip/post disposed concentrically within a laterally separated cavity and electrically contacting the substrate; and a gate electrode structure lying over the dielectric layer, including a like plurality of circular gate apertures, each gate aperture disposed concentrically above an emitter tip/post to provide a like plurality of annular gate electrodes and wherein the lower edge of each annular gate electrode proximate the like emitter tip/post is rounded. Also disclosed herein are methods for fabricating an integrated field emission array.

  19. Integrated field emission array for ion desorption

    Energy Technology Data Exchange (ETDEWEB)

    Resnick, Paul J; Hertz, Kristin L.; Holland, Christopher; Chichester, David

    2016-08-23

    An integrated field emission array for ion desorption includes an electrically conductive substrate; a dielectric layer lying over the electrically conductive substrate comprising a plurality of laterally separated cavities extending through the dielectric layer; a like plurality of conically-shaped emitter tips on posts, each emitter tip/post disposed concentrically within a laterally separated cavity and electrically contacting the substrate; and a gate electrode structure lying over the dielectric layer, including a like plurality of circular gate apertures, each gate aperture disposed concentrically above an emitter tip/post to provide a like plurality of annular gate electrodes and wherein the lower edge of each annular gate electrode proximate the like emitter tip/post is rounded. Also disclosed herein are methods for fabricating an integrated field emission array.

  20. Respiratory symptoms among industrial workers exposed to water aerosol. A pilot study of process water and air microbial quality

    Directory of Open Access Journals (Sweden)

    Bożena Krogulska

    2013-02-01

    Full Text Available Background: The frequency of respiratory symptoms in workers exposed to water aerosol was evaluated along with the preliminary assessment of microbiological contamination of air and water used in glass processing plants. Material and Methods: A questionnaire survey was conducted in 131 workers from 9 glass processing plants. Questions focused on working conditions, respiratory symptoms and smoking habits. A pilot study of air and water microbiological contamination in one glass processing plant was performed. Water samples were tested for Legionella in accordance with EN ISO 11731-2:2008 and for total colony count according to PN-EN ISO 6222:2004. Air samples were tested for total numbers of molds and mildews. Results: During the year preceding the survey acute respiratory symptoms occurred in 28.2% of participants, while chronic symptoms were reported by 29% of respondents. Increased risks of cough and acute symptoms suggestive of pneumonia were found among the respondents working at a distance up to 20 m from the source of water aerosol compared to other workers (OR = 2.7, with no difference in the frequency of other symptoms. A microbiological analysis of water samples from selected glass plant revealed the presence of L. pneumophila, exceeding 1000 cfu/100 ml. The number of bacteria and fungi detected in air samples (above 1000 cfu/m3 suggested that water aerosol at workplaces can be one of the sources of the air microbial contamination. Conclusions: The questionnaire survey revealed an increased risk of cough and acute symptoms suggestive of pneumonia in the group working at a shortest distance form the source of water aerosol. Med Pr 2013;64(1:47–55

  1. Copper desorption from Gelidium algal biomass.

    Science.gov (United States)

    Vilar, Vítor J P; Botelho, Cidália M S; Boaventura, Rui A R

    2007-04-01

    Desorption of divalent copper from marine algae Gelidium sesquipedale, an algal waste (from agar extraction industry) and a composite material (the algal waste immobilized in polyacrylonitrile) was studied in a batch system. Copper ions were first adsorbed until saturation and then desorbed by HNO(3) and Na(2)EDTA solutions. Elution efficiency using HNO(3) increases as pH decreases. At pH=1, for a solid to liquid ratio S/L=4gl(-1), elution efficiency was 97%, 95% and 88%, the stoichiometric coefficient for the ionic exchange, 0.70+/-0.02, 0.73+/-0.05 and 0.76+/-0.06 and the selectivity coefficient, 0.93+/-0.07, 1.0+/-0.3 and 1.1+/-0.3, respectively, for algae Gelidium, algal waste and composite material. Complexation of copper ions by EDTA occurs in a molar proportion of 1:1 and the elution efficiency increases with EDTA concentration. For concentrations of 1.4, 0.88 and 0.57 mmoll(-1), the elution efficiency for S/L=4gl(-1), was 91%, 86% and 78%, respectively, for algae Gelidium, algal waste and composite material. The S/L ratio, in the range 1-20gl(-1), has little influence on copper recovery by using 0.1M HNO(3). Desorption kinetics was very fast for all biosorbents. Kinetic data using HNO(3) as eluant were well described by the mass transfer model, considering the average metal concentration in the solid phase and the equilibrium relationship given by the mass action law. The homogeneous diffusion coefficient varied between 1.0 x 10(-7)cm(2)s(-1) for algae Gelidium and 3.0 x 10(-7)cm(2)s(-1) for the composite material.

  2. Application of a Hybrid Uf-Ro Process to Geothermal Water Desalination. Concentrate Disposal and Cost Analysis

    National Research Council Canada - National Science Library

    Barbara Tomaszewska; Leszek Pająk; Michał Bodzek

    2014-01-01

    M embrane-based water desalination processes and hybrid technologies are often considered as a technologically and economically viable alternative for desalination of geothermal waters. This has been...

  3. Operation, Modeling and Analysis of the Reverse Water Gas Shift Process

    Science.gov (United States)

    Whitlow, Jonathan E.

    2001-01-01

    The Reverse Water Gas Shift process is a candidate technology for water and oxygen production on Mars under the In-Situ Propellant Production project. This report focuses on the operation and analysis of the Reverse Water Gas Shift (RWGS) process, which has been constructed at Kennedy Space Center. A summary of results from the initial operation of the RWGS, process along with an analysis of these results is included in this report. In addition an evaluation of a material balance model developed from the work performed previously under the summer program is included along with recommendations for further experimental work.

  4. IMPROVEMENT OF COAGULATION PROCESS FOR THE PRUT RIVER WATER TREATMENT USING ALUMINUM SULPHATE

    Directory of Open Access Journals (Sweden)

    Larisa Postolachi

    2015-06-01

    Full Text Available The aim of presented research was to optimize the treatment process of the Prut River water. In order to realize the proposed goal, there were studied the following factors which can improve the process of coagulation: (i the influence of stirring speed during coagulation and (ii the influence of the concentration of the coagulant solution added in the process of coagulation. The optimal conditions of coagulation were established using the Jar-test method. Application of the recommended procedure contribute to the reduction of the coagulant dose, the contact time, the aluminum concentration in water and the expenses for water treatment.

  5. Solar Energy Supported Desalination Processes for Desalting of Sea Water

    OpenAIRE

    , M.E. Argun

    2010-01-01

    This study is a review of solar energy supported desalination processes. Although the sun light captured by earth excessively meets of world’s need, we can use a few amount of this source. Solar energy supported desalination is one of the method developed for desalination. Solar energy usage will also decrease CO2 emission which is responsible of global warming. A lot of studies to improve the efficiency of solar energy systems have been carried out during last years. Solar energy can be used...

  6. Sticking and desorption of hydrogen on graphite: A comparative study of different models

    Science.gov (United States)

    Lepetit, Bruno; Lemoine, Didier; Medina, Zuleika; Jackson, Bret

    2011-03-01

    We study the physisorption of atomic hydrogen on graphitic surfaces with four different quantum mechanical methods: perturbation and effective Hamiltonian theories, close coupling wavepacket, and reduced density matrix propagation methods. Corrugation is included in the modeling of the surface. Sticking is a fast process which is well described by all methods. Sticking probabilities are of the order of a few percent in the collision energy range 0-25 meV, but are enhanced for collision energies close to those of diffraction resonances. Sticking also increases with surface temperature. Desorption is a slow process which involves multiphonon processes. We show, however, how to correct the close coupling wavepacket method to account for such phenomena and obtain correct time constants for initial state decay. Desorption time constants are in the range of 20-50 ps for a surface temperature of 300 K.

  7. Chemical and ecotoxicological assessments of water samples before and after being processed by a Water Treatment Plant

    Directory of Open Access Journals (Sweden)

    Regina Teresa Rosim Monteiro

    2014-01-01

    Full Text Available Physicochemical and ecotoxicological measurements were employed to appraise the water quality of the Corumbataí River raw water (RW intake, and that of its filtered (FW and treated (TW waters, processed by the Water Treatment Plant (WTP of Piracicaba (SP, Brazil during 2010. Some herbicides: ametrine, atrazine, simazine and tebuthiuron, were measured, with levels ranging from 0.01 to 10.3 µg L-1 . These were lower than those required to produce ecotoxicological effects to aquatic life based on published literature. Similarly, trihalomethanes, such as chloroform and bromodichloromethane produced as a result of the WTP process were also shown to be present in concentrations that would neither harm environmental nor human health. Elevated free chlorine concentrations found in FW and TW were credibly responsible for toxicity effects observed in algae and daphnids. (Pseudokirchneriella subcapitata and Daphnia magna. In contrast, results of toxicity testing conducted with Hydra attenuata suggested that this organism is resistant to free chorine and could be used for drinking water evaluations. Coupling bioassays with chemical analyses proved valuable to uncover putative cause-effect relationships existing between physical, chemical and toxic results, as well as in optimizing data interpretation of water quality.

  8. Thermodynamics of the CO2–Absorption/Desorption Section in the Integrated Gasifying Combined cycle — II. Analysis

    Directory of Open Access Journals (Sweden)

    Jaroslav KOZACZKA

    2012-06-01

    Full Text Available The thermodynamic analysis of the absorption/desorption section of the ICGC–cycle has been presented using the Second Law with special emphasis on the thermodynamic effectivity concept and usability for complex systems investigations. Essential problems have been discussed based on the classical bibliographical items on the subject. Numerical calculations have been accomplished using results obtained in the first part, which contained absorption and desorption modeling approach oriented onto thermodynamic analyzes. Additionally the special properties of dilute solutions, especially the CO2/water system, have been presented and the problem of the solute chemical concentration exergy change suggested.

  9. Alternative Processes for Water Reclamation and Solid Waste Processing in a Physical/chemical Bioregenerative Life Support System

    Science.gov (United States)

    Rogers, Tom D.

    1990-01-01

    Viewgraphs on alternative processes for water reclamation and solid waste processing in a physical/chemical-bioregenerative life support system are presented. The main objective is to focus attention on emerging influences of secondary factors (i.e., waste composition, type and level of chemical contaminants, and effects of microorganisms, primarily bacteria) and to constructively address these issues by discussing approaches which attack them in a direct manner.

  10. Evaluating and Improving Water Treatment Plant Processes at Fixed Army Installations.

    Science.gov (United States)

    1985-05-01

    Activated Alumina Defluoridation Treatment Plants, National Sanitation Foundation, p 1. - 2 9 National Interim Primary Drinking Water Regulations, 40...7 RD-I7 306 EVALUATING AND IMPROVING WATER TREATMENT PLANT 1/2PROCESSES AT FIX~ED ARMY IN..U) CONSTRUCTIONENGINEERING RESEARCH LAB (ARMY) CHAMPAIGN...Corps C rof Engineers itECHNICAL REPORT N-85/10 Construction Engineering May 1985 Research Laboratory Technology for Upgrading Water Treatment Plants

  11. Desorption of hydrocarbon chains by association with ionic and nonionic surfactants under flow as a mechanism for enhanced oil recovery.

    Science.gov (United States)

    Terrón-Mejía, Ketzasmin A; López-Rendón, Roberto; Goicochea, Armando Gama

    2017-08-29

    The need to extract oil from wells where it is embedded on the surfaces of rocks has led to the development of new and improved enhanced oil recovery techniques. One of those is the injection of surfactants with water vapor, which promotes desorption of oil that can then be extracted using pumps, as the surfactants encapsulate the oil in foams. However, the mechanisms that lead to the optimal desorption of oil and the best type of surfactants to carry out desorption are not well known yet, which warrants the need to carry out basic research on this topic. In this work, we report non equilibrium dissipative particle dynamics simulations of model surfactants and oil molecules adsorbed on surfaces, with the purpose of studying the efficiency of the surfactants to desorb hydrocarbon chains, that are found adsorbed over flat surfaces. The model surfactants studied correspond to nonionic and cationic surfactants, and the hydrocarbon desorption is studied as a function of surfactant concentration under increasing Poiseuille flow. We obtain various hydrocarbon desorption isotherms for every model of surfactant proposed, under flow. Nonionic surfactants are found to be the most effective to desorb oil and the mechanisms that lead to this phenomenon are presented and discussed.

  12. Re-use of process water from norton water source; Hergebruik proceswater uit eigen nortonwaterbron

    Energy Technology Data Exchange (ETDEWEB)

    Rinia, R. [Milfac, Leeuwarden (Netherlands)

    1999-07-01

    At Coberco Zuivel (dairy industry) in Groningen, Netherlands, it appeared that the re-use of so-called norton water (groundwater) not only saves groundwater but also a considerable amount of energy. An overview is given of the set-up of the project, how it was carried out, the investment costs and the payback period.

  13. Design of a process for supercritical water desalination with zero liquid discharge

    NARCIS (Netherlands)

    Odu, Samuel Obarinu; van der Ham, Aloysius G.J.; Metz, S.; Kersten, Sascha R.A.

    2015-01-01

    Conventional desalination methods have a major drawback; the production of a liquid waste stream which must be disposed. The treatment of this waste stream has always presented technical, economic, and environmental challenges. The supercritical water desalination (SCWD) process meets these

  14. Enzymatic treatment of paper mill process waters; Entsyymit paperitehtaan kiertoveden kaesittelyssae - EKT 06

    Energy Technology Data Exchange (ETDEWEB)

    Mustranta, A.; Buchert, J. [VTT Biotechnology and Food Research, Espoo (Finland); Ekman, R.; Spetz, P. [Aabo Akademi, Turku (Finland). Lab. of Forest Products Chemistry; Luukko, K. [Helsinki Univ. of Technology, Otaniemi (Finland). Paper Technology

    1998-12-31

    Dissolved and colloidal substances (DCS) are dispersed into the process waters during different stages of pulp and paper production. These are lipophilic extractives (pitch), hydrophilic extractives (lignan) and carbohydrates, mainly hemicelluloses. These dissolved and colloidal substances accumulate during water circulation and results in impaired paper machine runnability. DCS can also interfere with wet-end process chemicals. In this project the chemical composition of the process waters of spruce TMP pulping have been characterized. Simultaneously, potential enzymes for modification of DCS has been produced and purified. The enzymatic treatments have been started with lipase acting on triglycerides present in extractives. The effect of enzymatic treatment on the properties of process waters and technical properties of the pulp have been evaluated. (orig.)

  15. Dispersion processes in coastal waters - Some outstanding practical issues for monitoring and modelling

    Digital Repository Service at National Institute of Oceanography (India)

    Swamy, G.N.

    This paper highlights on the issues of dispersion processes in coastal waters like space-time description of field parameters, limitation of physical models, limitations of numerical formulations, Eulerian-Lagrangian transformations, shear...

  16. Post-treatment of reclaimed waste water based on an electrochemical advanced oxidation process

    Science.gov (United States)

    Verostko, Charles E.; Murphy, Oliver J.; Hitchens, G. D.; Salinas, Carlos E.; Rogers, Tom D.

    1992-01-01

    The purification of reclaimed water is essential to water reclamation technology life-support systems in lunar/Mars habitats. An electrochemical UV reactor is being developed which generates oxidants, operates at low temperatures, and requires no chemical expendables. The reactor is the basis for an advanced oxidation process in which electrochemically generated ozone and hydrogen peroxide are used in combination with ultraviolet light irradiation to produce hydroxyl radicals. Results from this process are presented which demonstrate concept feasibility for removal of organic impurities and disinfection of water for potable and hygiene reuse. Power, size requirements, Faradaic efficiency, and process reaction kinetics are discussed. At the completion of this development effort the reactor system will be installed in JSC's regenerative water recovery test facility for evaluation to compare this technique with other candidate processes.

  17. Criticality Safety Evaluation Report for the Cold Vacuum Drying (CVD) Facilities Process Water Handling System

    Energy Technology Data Exchange (ETDEWEB)

    KESSLER, S.F.

    2000-08-10

    This report addresses the criticality concerns associated with process water handling in the Cold Vacuum Drying Facility. The controls and limitations on equipment design and operations to control potential criticality occurrences are identified.

  18. Selective oxidation of organic compounds in waste water by ozone-based oxidation processes

    NARCIS (Netherlands)

    Boncz, M.A.

    2002-01-01

    For many different types of waste water, treatment systems have been implemented in the past decades. Waste water treatment is usually performed by biological processes, either aerobic or anaerobic, complemented with physical / chemical post treatment techniques.

  19. A model to estimate hydrological processes and water budget in an irrigation farm pond

    Science.gov (United States)

    Ying Ouyang; Joel O. Paz; Gary Feng; John J. Read; Ardeshir Adeli; Johnie N. Jenkins

    2017-01-01

    With increased interest to conserve groundwater resources without reducing crop yield potential, more on-farm water storage ponds have been constructed in recent years in USA and around the world. However, the hydrological processes, water budget, and environmental benefits and consequences of these ponds have not yet been fully quantified. This study developed a...

  20. Impacts of Ocean Acidification on Sediment Processes in Shallow Waters of the Arctic Ocean

    NARCIS (Netherlands)

    Gazeau, F.; van Rijswijk, P.; Pozzato, L.; Middelburg, J.J.

    2014-01-01

    Despite the important roles of shallow-water sediments in global biogeochemical cycling, the effects of ocean acidification on sedimentary processes have received relatively little attention. As high-latitude cold waters can absorb more CO2 and usually have a lower buffering capacity than warmer

  1. Impacts of ocean acidification on sediment processes in shallow waters of the Arctic Ocean

    NARCIS (Netherlands)

    Gazeau, F.; van Rijswijk, P.; Pozzato, L.; Middelburg, J.J.|info:eu-repo/dai/nl/079665373

    Despite the important roles of shallow-water sediments in global biogeochemical cycling, the effects of ocean acidification on sedimentary processes have received relatively little attention. As high-latitude cold waters can absorb more CO2 and usually have a lower buffering capacity than warmer

  2. Investigation of microbial communities on reverse osmosis membranes used for process water production

    NARCIS (Netherlands)

    Bereschenko, L.A.; Stams, A.J.M.; Heilig, G.H.J.; Euverink, G.J.W.; Nederlof, M.M.; Loosdrecht, M.C.M.

    2007-01-01

    In the present study, the diversity and the phylogenetic affiliation of bacteria in a biofouling layer on reverse osmosis (RO) membranes were determined. Fresh surface water was used as a feed in a membrane-based water purification process. Total DNA was extracted from attached cells from feed

  3. High efficient ammonia heat pump system for industrial process water using the ISEC concept. Part 1

    DEFF Research Database (Denmark)

    Rothuizen, Erasmus Damgaard; Madsen, C.; Elmegaard, Brian

    2014-01-01

    The purpose of the Isolated System Energy Charging (ISEC) is to provide a high-efficient ammonia heat pump system for hot water production. The ISEC concept uses two storage tanks for the water, one discharged and one charged. The charged tank is used for the industrial process while the discharg...

  4. Integrating Process and Factor Understanding of Environmental Innovation by Water Utilities

    NARCIS (Netherlands)

    Spiller, Marc; McIntosh, Brian S.; Seaton, Roger A.F.; Jeffrey, Paul J.

    2015-01-01

    Innovations in technology and organisations are central to enabling the water sector to adapt to major environmental changes such as climate change, land degradation or drinking water pollution. While there are literatures on innovation as a process and on the factors that influence it, there is

  5. A system dynamic model to estimate hydrological processes and water use in a eucalypt plantation

    Science.gov (United States)

    Ying Ouyang; Daping Xu; Ted Leininger; Ningnan Zhang

    2016-01-01

    Eucalypts have been identified as one of the best feedstocks for bioenergy production due to theirfast-growth rate and coppicing ability. However, their water use efficiency along with the adverse envi-ronmental impacts is still a controversial issue. In this study, a system dynamic model was developed toestimate the hydrological processes and water use in a eucalyptus...

  6. Electron Stimulated Molecular Desorption of a NEG St 707 at Room Temperature

    CERN Document Server

    Le Pimpec, F; Laurent, Jean Michel

    2001-01-01

    Electron stimulated molecular desorption (ESD) from a NEG St 707 (SAES GettersTM) sample after conditioning and after saturation with isotopic carbon monoxide2,13C18O, has been studied on a laboratory setup. Measurements were performed using an electron beam of 300 eV kinetic energy, with an average electron intensity of 1.6 1015 electrons s-1. The electrons were impinging on the 15 cm2 target surface at perpendicular incidence. It is found that the desorption yields h (molecules/electron) of the characteristic gases in an UHV system (hydrogen, methane, water, carbon monoxide, carbon dioxide) for a fully activated NEG as well as for a NEG fully saturated with 13C18O are lower than for OFHC copper baked at 120oC. A small fraction only of the gas which is required to saturate the getter surface can be re-desorbed and thus appears to be accessible to ESD.

  7. The influences of separators on capacitive deionization systems in the cycle of adsorption and desorption.

    Science.gov (United States)

    Yao, Qihan; Shi, Zhou; Liu, Qingqing; Gu, Zhengyang; Ning, Ruihuan

    2017-11-17

    This research focused on the influence of different separator compartments on the performance of capacitive deionization (CDI) cells in terms of brackish water treatment. For comparison, different separators including filter paper(FP), carbon nanotube (CNT), and stainless steel fiber (SSF) on deionization and desorption rate of salt were examined. The best performance was obtained when the CNT separator was packed, followed by SSF and FP. Reducing the cell voltage from 1.2 to 0.4 V decreased the salt removal and electrode regeneration rate of SSF-CDI. Electrochemical impedance spectrometry (EIS) analysis revealed that the resistance and specific capacitance of separator materials are essential to the desalination and desorption performance of CDI. The electric double layers (EDLs) accelerated the ion transfer in the flow chamber due to storing excess ions, therefore increasing the desalination and electrode regeneration rate.

  8. Development and Validation of an Acid Mine Drainage Treatment Process for Source Water

    Energy Technology Data Exchange (ETDEWEB)

    Lane, Ann [Battelle Memorial Institute, Columbus, OH (United States)

    2016-03-01

    Throughout Northern Appalachia and surrounding regions, hundreds of abandoned mine sites exist which frequently are the source of Acid Mine Drainage (AMD). AMD typically contains metal ions in solution with sulfate ions which have been leached from the mine. These large volumes of water, if treated to a minimum standard, may be of use in Hydraulic Fracturing (HF) or other industrial processes. This project’s focus is to evaluate an AMD water treatment technology for the purpose of providing treated AMD as an alternative source of water for HF operations. The HydroFlex™ technology allows the conversion of a previous environmental liability into an asset while reducing stress on potable water sources. The technology achieves greater than 95% water recovery, while removing sulfate to concentrations below 100 mg/L and common metals (e.g., iron and aluminum) below 1 mg/L. The project is intended to demonstrate the capability of the process to provide AMD as alternative source water for HF operations. The second budget period of the project has been completed during which Battelle conducted two individual test campaigns in the field. The first test campaign demonstrated the ability of the HydroFlex system to remove sulfate to levels below 100 mg/L, meeting the requirements indicated by industry stakeholders for use of the treated AMD as source water. The second test campaign consisted of a series of focused confirmatory tests aimed at gathering additional data to refine the economic projections for the process. Throughout the project, regular communications were held with a group of project stakeholders to ensure alignment of the project objectives with industry requirements. Finally, the process byproduct generated by the HydroFlex process was evaluated for the treatment of produced water against commercial treatment chemicals. It was found that the process byproduct achieved similar results for produced water treatment as the chemicals currently in use. Further

  9. Desorption process of hydrogen starting from the Mg{sub 2}NiH{sub 4} and Mg{sub 2}NiH{sub 0.3}; Proceso de desorcion de hidrogeno a partir del hidruro intermetalico Mg{sub 2}NiH{sub 4} y Mg{sub 2}NiH{sub 0.3}

    Energy Technology Data Exchange (ETDEWEB)

    Iturbe G, J.L.; Basurto S, R.; Lopez M, B.E. [Departamento de Quimica, ININ, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

    2002-07-01

    In this work the desorption velocity of H{sub 2} was determined starting from the magnesium nickel hydride once the reaction between the intermetallic and the hydrogen was realized, the compound were analysed by means of a thermogravimetric equipment, the conditions for carrying out the analysis were: 10 C by minute in nitrogen atmosphere at a volume of 50 ml by minute, subsequently the isotherms at different times were programmed and the desorption velocity of hydrogen was determined. The results show that the desorption velocity of hydrogen depends of the temperature, using only the nitrogen flux which acts as a carrier gas. Observing that the hydrogen liberation is carried out by means of two mechanisms according to the isotherms obtained. (Author)

  10. Guidelines for inclusion: Ensuring Indigenous peoples' involvement in water planning processes across South Eastern Australia

    Science.gov (United States)

    Saenz Quitian, Alejandra; Rodríguez, Gloria Amparo

    2016-11-01

    Indigenous peoples within the Murray-Darling Basin have traditionally struggled for the recognition of their cultural, social, environmental, spiritual, commercial and economic connection to the waters that they have traditionally used, as well as their right to engage in all stages of water planning processes. Despite Australian national and federal frameworks providing for the inclusion of Indigenous Australians' objectives in planning frameworks, water plans have rarely addressed these objectives in water, or the strategies to achieve them. Indeed, insufficient resources, a lack of institutional capacity in both Indigenous communities and agencies and an inadequate understanding of Indigenous people's objectives in water management have limited the extent to which Indigenous objectives are addressed in water plans within the Murray-Darling Basin. In this context, the adoption of specific guidelines to meet Indigenous requirements in relation to basin water resources is crucial to support Indigenous engagement in water planning processes. Using insights from participatory planning methods and human rights frameworks, this article outlines a set of alternative and collaborative guidelines to improve Indigenous involvement in water planning and to promote sustainable and just water allocations.

  11. Electropulse treatment of water solution of humic substances in a layer iron granules in process of water treatment

    Science.gov (United States)

    Lobanova, G. L.; Yurmazova, T. A.; Shiyan, L. N.; Machekhina, K. I.

    2016-02-01

    The present work is a part of a continuations study of the physical and chemical processes complex in natural waters containing humic-type organic substances at the influence of pulsed electrical discharges in a layer of iron pellets. The study of humic substances processing in the iron granules layer by means of pulsed electric discharge for the purpose of water purification from organic compounds humic origin from natural water of the northern regions of Russia is relevant for the water treatment technologies. In case of molar humate sodium - iron ions (II) at the ratio 2:3, reduction of solution colour and chemical oxygen demand occur due to the humate sodium ions and iron (II) participation in oxidation-reduction reactions followed by coagulation insoluble compounds formation at a pH of 6.5. In order to achieve this molar ratio and the time of pulsed electric discharge, equal to 10 seconds is experimentally identified. The role of secondary processes that occur after disconnection of the discharge is shown. The time of contact in active erosion products with sodium humate, equal to 1 hour is established. During this time, the value of permanganate oxidation and iron concentration in solution achieves the value of maximum permissible concentrations and further contact time increase does not lead to the controlled parameters change.

  12. Scaling up ecohydrological processes: role of surface water flow in water-limited landscapes

    CSIR Research Space (South Africa)

    Popp, A

    2009-11-01

    Full Text Available In this study, the authors present a stochastic landscape modeling approach that has the power to transfer and integrate existing information on vegetation dynamics and hydrological processes from the small scale to the landscape scale. To include...

  13. Thermal desorption of Au from W(001) surface

    CERN Document Server

    Blaszczyszyn, R; Godowski, P J

    2002-01-01

    Adsorption of Au on W(001) at 450 K up to multilayer structures was investigated. Temperature programmed desorption technique was used in determination of coverage dependent desorption energy (region up to one monolayer). Results were discussed in terms of competitive interactions of Au-Au and Au-W atoms. Simple procedure for prediction of faceting behavior on the interface, basing on the desorption data, was postulated. It was deduced that the Au/W(001) interface should not show faceting tendency after thermal treatment. (author)

  14. Application of ASTM E-1559 Apparatus to Study H2O Desorption

    Science.gov (United States)

    Woronowicz, Michael; Perry, Radford, III; Meadows, George A.

    2015-01-01

    The NASA James Webb Space Telescope project identified a need to measure water vapor desorption from cryogenic surfaces in order to validate predictions of spacecraft design performance. A review of available scientific literature indicated no such measurements had been reported below 131 K. Contamination control personnel at NASA Goddard Space Flight Center recognized the possibility they readily possessed the means to collect these measurements at lower temperatures using an existing apparatus commonly employed for making outgassing observations. This presentation will relate how the ASTM E-1559 Molekit apparatus was used without physical modification to measure water vapor sublimation down to 120 K and compare this data to existing equilibrium vapor pressure models.

  15. Why infrastructure still matters: unravelling water reform processes in an uneven waterscape in rural Kenya

    Directory of Open Access Journals (Sweden)

    Jeltsje Sanne Kemerink

    2016-08-01

    Full Text Available Since the 1980s, a major change took place in public policies for water resources management. Whereas before governments primarily invested in the development, operation and maintenance of water infrastructure and were mainly concerned with the distribution of water, in the new approach they mainly focus on managing water resources systems by stipulating general frameworks for water allocation. This paper studies the rationales used to justify the water reform process in Kenya and discusses how and to what extent these rationales apply to different groups of water users within Likii catchment in the central part of the country. Adopting a critical institutionalist's perspective, this paper shows how the water resource configurations in the catchment are constituted by the interplay between a normative policy model introduced in a plural institutional context and the disparate infrastructural options available to water users as result of historically produced uneven social relations. We argue that, to progressively redress the colonial legacy, direct investments in infrastructure for marginalized water users and targeting the actual (redistribution of water to the users might be more effective than focusing exclusively on institutional reforms.

  16. Ozone pretreatment of process waste water generated in course of fluoroquinolone production.

    Science.gov (United States)

    Daoud, Fares; Pelzer, David; Zuehlke, Sebastian; Spiteller, Michael; Kayser, Oliver

    2017-10-01

    During production of active pharmaceutical ingredients, process waste water is generated at several stages of manufacturing. Whenever possible, the resulting waste water will be processed by conventional waste water treatment plants. Currently, incineration of the process waste water is the method to eliminate compounds with high biological activity. Thus, ozone treatment followed by biological waste water treatment was tested as an alternative method. Two prominent representatives of the large group of fluoroquinolone antibiotics (ciprofloxacin and moxifloxacin) were investigated, focussing on waste water of the bulk production. Elimination of the target compounds and generation of their main transformation products were determined by liquid chromatography - high resolution mass spectrometry (LC-HRMS). The obtained results demonstrated, that the concentration of moxifloxacin and its metabolites can be effectively reduced (>99.7%) prior entering the receiving water. On the contrary, the concentration of ciprofloxacin and its metabolites remained too high for safe discharge, necessitating application of prolonged ozonation for its further degradation. The required ozonation time can be estimated based on the determined kinetics. To assure a low biological activity the ecotoxicity of the ozonated waste water was investigated using three trophic levels. By means of multiple-stage mass spectrometry (MSn) experiments several new transformation products of the fluoroquinolones were identified. Thus, previously published proposed structures could be corrected or confirmed. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Experimental Application of an Advanced Separation Process for NOM Removal from Surface Drinking Water Supply

    Directory of Open Access Journals (Sweden)

    Arianna Callegari

    2017-10-01

    Full Text Available Natural organic matter (NOM in drinking water supplies significantly impacts on water supply quality and treatment, due to observed reactivity with many dissolved and particulate species. Several technologies are used nowadays to remove NOM from the water supply. The evolution of water-related directives, and progressively more restrictive standards for drinking water, however, call for the investigation of advanced, more efficient, and cost-effective water treatment processes. This paper contains a brief overview on the state-of-the-art methods for NOM removal from supply waters, and describes the experimental application of an advanced technology, tested and validated at the pilot scale on the water supply source of a town in Poland. The process allowed significant removal of natural organic matter (about 50% as Dissolved Organic Carbon and turbidity (from 50% to 90%, however, these results requested significant additions of powdered activated carbon. The key to success of this type of process is a correct setup with the identification of optimal types and dosages of reagents. Based on the results of the tests conducted it is foreseeable that this technology could be used onsite, not only for removal of NOM, but also of other hard-to-tackle pollutants potentially contained in the freshwater supply and not presently considered.

  18. Comparison of microbial community shifts in two parallel multi-step drinking water treatment processes.

    Science.gov (United States)

    Xu, Jiajiong; Tang, Wei; Ma, Jun; Wang, Hong

    2017-07-01

    Drinking water treatment processes remove undesirable chemicals and microorganisms from source water, which is vital to public health protection. The purpose of this study was to investigate the effects of treatment processes and configuration on the microbiome by comparing microbial community shifts in two series of different treatment processes operated in parallel within a full-scale drinking water treatment plant (DWTP) in Southeast China. Illumina sequencing of 16S rRNA genes of water samples demonstrated little effect of coagulation/sedimentation and pre-oxidation steps on bacterial communities, in contrast to dramatic and concurrent microbial community shifts during ozonation, granular activated carbon treatment, sand filtration, and disinfection for both series. A large number of unique operational taxonomic units (OTUs) at these four treatment steps further illustrated their strong shaping power towards the drinking water microbial communities. Interestingly, multidimensional scaling analysis revealed tight clustering of biofilm samples collected from different treatment steps, with Nitrospira, the nitrite-oxidizing bacteria, noted at higher relative abundances in biofilm compared to water samples. Overall, this study provides a snapshot of step-to-step microbial evolvement in multi-step drinking water treatment systems, and the results provide insight to control and manipulation of the drinking water microbiome via optimization of DWTP design and operation.

  19. A tool to increase information-processing capacity for consumer water meter data

    Directory of Open Access Journals (Sweden)

    Heinz E. Jacobs

    2012-02-01

    increased the information processing capacity for water meter data.

  20. Research on water-exit and take-off process for Morphing Unmanned Submersible Aerial Vehicle

    Science.gov (United States)

    Hu, Jun-hua; Xu, Bao-wei; Feng, Jin-fu; Qi, Duo; Yang, Jian; Wang, Cong

    2017-04-01

    This paper presents a theoretic implementation method of Morphing Unmanned Submersible Aerial Vehicle (MUSAV), which can both submerge in the water and fly in the air. Two different shapes are put forward so that the vehicle can suit both submergence and flight, considering the tremendous differences between hydrodynamic configuration and aerodynamic configuration of a vehicle. The transition of the two shapes can be achieved by using morphing technology. The water-to-air process, including water-exit, morphing, take-off and steady flight, is analyzed. The hydrodynamic and aerodynamic model of the vehicle exiting the water surface obliquely and then taking off into the air has been founded. The control strategy after morphing is analyzed and the control method is given. Numerical method is used to validate the motion model of the water-exit process. Results of simulations show the validity of the proposed model and the feasibility of MUSAV in theory.

  1. Comparison of filtering methods, filter processing and DNA extraction kits for detection of mycobacteria in water

    Directory of Open Access Journals (Sweden)

    Marija Kaevska

    2015-09-01

    Full Text Available Introduction and objective. Mycobacteria have been isolated from almost all types of natural waters, as well as from man-made water distribution systems. Detection of mycobacteria using PCR has been described in different types of water; however, currently, there is no standardised protocol for the processing of large volumes of water. Material and Methods. In the present study, different filtering methods are tested and optimised for tap or river water filtration up to 10 L, as well as filter processing and DNA isolation using four commercially available kits. Results. The PowerWater DNA isolation kit (MoBio, USA, together with a kit used for soil and other environmental samples (PowerSoil DNA isolation kit, MoBio, had the highest efficiency. Filtration of 10 L of water and elution of the filter in PBS with the addition of 0.05% of Tween 80 is suggested. Conclusions. The described protocol for filter elution is recommended, and the use of the PowerWater DNA isolation kit for the highest mycobacterial DNA yield from water samples. The described protocol is suitable for parallel detection of mycobacteria using cultivation.

  2. Problems of treatment process selection for relief agency water supplies in an emergency.

    Science.gov (United States)

    Steele, Andre; Clarke, Brian

    2008-12-01

    There is currently limited public information available concerning methods for the selection of appropriate water treatment technologies for application in acute phase emergency water and sanitation responses. Considering the number of available emergency water treatment and supply options, it is speculated that a framework methodology offering guidance in the form of a selection process would offer advantages. This process would relate a defined set of emergency factors to a selection of available water treatment and supply options, described by a basic, but complete, set of technical and operational characteristics. It is suggested that, whilst not a complete process, the proposed framework methodology is sufficient to lead to the identification and selection of appropriate options for deployment. Furthermore the support of critical decision making by a logical framework, could help shape and justify the actions of agencies and workers in the field. Copyright IWA Publishing 2008.

  3. Microbial Community Structures and Dynamics in the O3/BAC Drinking Water Treatment Process

    Directory of Open Access Journals (Sweden)

    Jian Tian

    2014-06-01

    Full Text Available Effectiveness of drinking water treatment, in particular pathogen control during the water treatment process, is always a major public health concern. In this investigation, the application of PCR-DGGE technology to the analysis of microbial community structures and dynamics in the drinking water treatment process revealed several dominant microbial populations including: α-Proteobacteria, β-Proteobacteria, γ-Proteobacteria, Bacteroidetes, Actinobacteria Firmicutes and Cyanobacteria. α-Proteobacteria and β-Proteobacteria were the dominant bacteria during the whole process. Bacteroidetes and Firmicutes were the dominant bacteria before and after treatment, respectively. Firmicutes showed season-dependent changes in population dynamics. Importantly, γ-Proteobacteria, which is a class of medically important bacteria, was well controlled by the O3/biological activated carbon (BAC treatment, resulting in improved effluent water bio-safety.

  4. Microbial community structures and dynamics in the O3/BAC drinking water treatment process.

    Science.gov (United States)

    Tian, Jian; Lu, Jun; Zhang, Yu; Li, Jian-Cheng; Sun, Li-Chen; Hu, Zhang-Li

    2014-06-16

    Effectiveness of drinking water treatment, in particular pathogen control during the water treatment process, is always a major public health concern. In this investigation, the application of PCR-DGGE technology to the analysis of microbial community structures and dynamics in the drinking water treatment process revealed several dominant microbial populations including: α-Proteobacteria, β-Proteobacteria, γ-Proteobacteria, Bacteroidetes, Actinobacteria Firmicutes and Cyanobacteria. α-Proteobacteria and β-Proteobacteria were the dominant bacteria during the whole process. Bacteroidetes and Firmicutes were the dominant bacteria before and after treatment, respectively. Firmicutes showed season-dependent changes in population dynamics. Importantly, γ-Proteobacteria, which is a class of medically important bacteria, was well controlled by the O3/biological activated carbon (BAC) treatment, resulting in improved effluent water bio-safety.

  5. EUTROPHICATION OF WATER RESERVOIRS AND ROLE OF MACROPHYTES IN THIS PROCESS

    Directory of Open Access Journals (Sweden)

    Joanna Jadwiga Sender

    2017-06-01

    Full Text Available The paper presents the problem related with the process of eutrophication, with special emphasis on dam reservoirs. Eutrophication is a global process, threatening the water ecosystem on every continent. It often leads to their degradation. Particularly vulnerable to eutrophication are artificial reservoirs which are dam reservoirs. This paper describes the mechanisms of eutrophication. We also pointed to the importance of aquatic plants in the process of water purification, as well as the possibility of multilateral use. Recently, in the world and in Poland there is a tendency to pay attention to the natural or semi-natural method of water purification (including constructed wetland. On the one hand, the presence of macrophytes in water bodies is a guarantor of good ecological status, on the other hand, the undeniable aesthetic value.

  6. Application of volume-retarded osmosis and low-pressure membrane hybrid process for water reclamation

    KAUST Repository

    Im, Sung-Ju

    2017-11-15

    A new concept of volume-retarded osmosis and low-pressure membrane (VRO-LPM) hybrid process was developed and evaluated for the first time in this study. Commercially available forward osmosis (FO) and ultrafiltration (UF) membranes were employed in a VRO-LPM hybrid process to overcome energy limitations of draw solution (DS) regeneration and production of permeate in the FO process. To evaluate its feasibility as a water reclamation process, and to optimize the operational conditions, cross-flow FO and dead-end mode UF processes were individually evaluated. For the FO process, a DS concentration of 0.15 g mL−1 of polysulfonate styrene (PSS) was determined to be optimal, having a high flux with a low reverse salt flux. The UF membrane with a molecular weight cut-off of 1 kDa was chosen for its high PSS rejection in the LPM process. As a single process, UF (LPM) exhibited a higher flux than FO, but this could be controlled by adjusting the effective membrane area of the FO and UF membranes in the VRO-LPM system. The VRO-LPM hybrid process only required a circulation pump for the FO process. This led to a decrease in the specific energy consumption of the VRO-LPM process for potable water production, that was similar to the single FO process. Therefore, the newly developed VRO-LPM hybrid process, with an appropriate DS selection, can be used as an energy efficient water production method, and can outperform conventional water reclamation processes.

  7. Reuse of process water in a waste-to-energy plant: An Italian case of study.

    Science.gov (United States)

    Gardoni, Davide; Catenacci, Arianna; Antonelli, Manuela

    2015-09-01

    The minimisation of water consumption in waste-to-energy (WtE) plants is an outstanding issue, especially in those regions where water supply is critical and withdrawals come from municipal waterworks. Among the various possible solutions, the most general, simple and effective one is the reuse of process water. This paper discusses the effectiveness of two different reuse options in an Italian WtE plant, starting from the analytical characterisation and the flow-rate measurement of fresh water and process water flows derived from each utility internal to the WtE plant (e.g. cooling, bottom ash quenching, flue gas wet scrubbing). This census allowed identifying the possible direct connections that optimise the reuse scheme, avoiding additional water treatments. The effluent of the physical-chemical wastewater treatment plant (WWTP), located in the WtE plant, was considered not adequate to be directly reused because of the possible deposition of mineral salts and clogging potential associated to residual suspended solids. Nevertheless, to obtain high reduction in water consumption, reverse osmosis should be installed to remove non-metallic ions (Cl(-), SO4(2-)) and residual organic and inorganic pollutants. Two efficient solutions were identified. The first, a simple reuse scheme based on a cascade configuration, allowed 45% reduction in water consumption (from 1.81 to 0.99m(3)tMSW(-1), MSW: Municipal Solid Waste) without specific water treatments. The second solution, a cascade configuration with a recycle based on a reverse osmosis process, allowed 74% reduction in water consumption (from 1.81 to 0.46m(3)tMSW(-1)). The results of the present work show that it is possible to reduce the water consumption, and in turn the wastewater production, reducing at the same time the operating cost of the WtE plant. Copyright © 2015 Elsevier Ltd. All rights reserved.

  8. A Coupled Groundwater-Surface Water Modeling Framework for Simulating Transition Zone Processes.

    Science.gov (United States)

    Mugunthan, Pradeep; Russell, Kevin T; Gong, Binglei; Riley, Michael J; Chin, Arthur; McDonald, Blair G; Eastcott, Linda J

    2017-05-01

    There is an identified need for fully representing groundwater-surface water transition zone (i.e., the sediment zone that connects groundwater and surface water) processes in modeling fate and transport of contaminants to assist with management of contaminated sediments. Most existing groundwater and surface water fate and transport models are not dynamically linked and do not consider transition zone processes such as bioturbation and deposition and erosion of sediments. An interface module is developed herein to holistically simulate the fate and transport by coupling two commonly used models, Environmental Fluid Dynamics Code (EFDC) and SEAWAT, to simulate surface water and groundwater hydrodynamics, while providing an enhanced representation of the processes in the transition zone. Transition zone and surface water contaminant processes were represented through an enhanced version of the EFDC model, AQFATE. AQFATE also includes SEDZLJ, a state-of-the-science surface water sediment transport model. The modeling framework was tested on a published test problem and applied to evaluate field-scale two- and three-dimensional contaminant transport. The model accurately simulated concentrations of salinity from a published test case. For the field-scale applications, the model showed excellent mass balance closure for the transition zone and provided accurate simulations of all transition zone processes represented in the modeling framework. The model predictions for the two-dimensional field case were consistent with site-specific observations of contaminant migration. This modeling framework represents advancement in the simulation of transition zone processes and can help inform risk assessment at sites where contaminant sources from upland areas have the potential to impact sediments and surface water. © 2016, National Ground Water Association.

  9. Temperature-Induced Desorption of Methyl tert-Butyl Ether Confined on ZSM-5: An In Situ Synchrotron XRD Powder Diffraction Study

    Directory of Open Access Journals (Sweden)

    Elisa Rodeghero

    2017-02-01

    Full Text Available The temperature-induced desorption of methyl tert-butyl ether (MTBE from aqueous solutions onto hydrophobic ZSM-5 was studied by in situ synchrotron powder diffraction and chromatographic techniques. This kind of information is crucial for designing and optimizing the regeneration treatment of such zeolite. The evolution of the structural features monitored by full profile Rietveld refinements revealed that a monoclinic (P21/n to orthorhombic (Pnma phase transition occurred at about 100 °C. The MTBE desorption process caused a remarkable change in the unit-cell parameters. Complete MTBE desorption was achieved upon heating at about 250 °C. Rietveld analysis demonstrated that the desorption process occurred without any significant zeolite crystallinity loss, but with slight deformations in the channel apertures.

  10. Water column velocimeter for NSRR experiment. Characteristics and data processing procedure

    Energy Technology Data Exchange (ETDEWEB)

    Sugiyama, Tomoyuki; Fuketa, Toyoshi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2000-11-01

    In order to clarify fuel behavior under reactivity initiated accident (RIA) conditions, pulse irradiation experiments on fuel rods are carried out in the Nuclear Safety Research Reactor (NSRR). One of concerns at fuel failure is mechanical energy generation in the reactor vessel. The mechanical energy is generated by a water hammer or a pressure impact occurred at fuel failure, and has possibility to damage reactor structures. Thus, the amount of generated mechanical energy is critical information for the safety evaluation of power reactor. In the NSRR experiments, the mechanical energy due to the water hammer is evaluated as the kinetic energy of the jumping water column at fuel failure, and the velocity of the water column is measured by the float type water column velocimeter. This report presents characteristics of the water column velocimeter and the procedure of data processing in the NSRR experiments. (author)

  11. Process Water Recycle in Hydrothermal Liquefaction of Microalgae To Enhance Bio-oil Yield

    NARCIS (Netherlands)

    Ramos-Tercero, E.A.; Bertucco, A.; Brilman, Derk Willem Frederik

    2015-01-01

    In this work, the effect of recycling the process water (PW) of hydrothermal liquefaction (HTL) to the HTL reactor was investigated, with the objective being to recover carbon from the organic content of the PW and to develop a solvent-free process. When recycling twice the PW at 220, 240, and 265

  12. Pb-Sr isotopic and geochemical constraints on sources and processes of lead contamination in well waters and soil from former fruit orchards, Pennsylvania, USA: A legacy of anthropogenic activities

    Science.gov (United States)

    Ayuso, Robert A.; Foley, Nora K.

    2016-01-01

    Isotopic discrimination can be an effective tool in establishing a direct link between sources of Pb contamination and the presence of anomalously high concentrations of Pb in waters, soils, and organisms. Residential wells supplying water containing up to 1600 ppb Pb to houses built on the former Mohr orchards commercial site, near Allentown, PA, were evaluated to discern anthropogenic from geogenic sources. Pb (n = 144) and Sr (n = 40) isotopic data and REE (n = 29) data were determined for waters from residential wells, test wells (drilled for this study), and surface waters from pond and creeks. Local soils, sediments, bedrock, Zn-Pb mineralization and coal were also analyzed (n = 94), together with locally used Pb-As pesticide (n = 5). Waters from residential and test wells show overlapping values of 206Pb/207Pb, 208Pb/207Pb and 87Sr/86Sr. Larger negative Ce anomalies (Ce/Ce*) distinguish residential wells from test wells. Results show that residential and test well waters, sediments from residential water filters in water tanks, and surface waters display broad linear trends in Pb isotope plots. Pb isotope data for soils, bedrock, and pesticides have contrasting ranges and overlapping trends. Contributions of Pb from soils to residential well waters are limited and implicated primarily in wells having shallow water-bearing zones and carrying high sediment contents. Pb isotope data for residential wells, test wells, and surface waters show substantial overlap with Pb data reflecting anthropogenic actions (e.g., burning fossil fuels, industrial and urban processing activities). Limited contributions of Pb from bedrock, soils, and pesticides are evident. High Pb concentrations in the residential waters are likely related to sediment build up in residential water tanks. Redox reactions, triggered by influx of groundwater via wells into the residential water systems and leading to subtle changes in pH, are implicated in precipitation of Fe oxyhydroxides

  13. [Water quality safety of ozonation and biologically activated carbon process in application].

    Science.gov (United States)

    Qiao, Tie-Jun; Zhang, Xi-Hui

    2009-11-01

    Ozonation and biologically activated carbon process, one of advanced treatment technologies, has been applied in many places at home and abroad. However, some emerging water quality problems appeared in operation. Drinking water treatment plant (6 x 10(5) m3/d) with ozonation and biologically activated carbon process (O3-BAC process) was investigated systematically, including microbial safety, the excessive growth of aquatic microorganism and chemical stability of water quality. And some experiments were done in the pilot plant (10 m3/h) at the same time. O3-BAC process is reliable in microbial safety, but operation management should be enhanced. A good number of aquatic microorganisms grow immoderately during operation of O3-BAC process, which is more serious especially in place with high temperature and humidity. With prolong of runtime, the growth of aquatic microorganisms varies regularly. That is hazardous to water quality safety. When raw water is low with alkalinity, decrease of pH in O3-BAC process is obvious. That will seriously affect on chemical stability.

  14. Treatment of sewage sludge in supercritical water and evaluation of the combined process of supercritical water gasification and oxidation.

    Science.gov (United States)

    Qian, Lili; Wang, Shuzhong; Xu, Donghai; Guo, Yang; Tang, Xingying; Wang, Longfei

    2015-01-01

    Influences of temperature and oxidation coefficient (n) on sewage sludge treatment in supercritical water and its corresponding reaction mechanism were studied. Moreover, the combined process of supercritical water gasification (SCWG) and supercritical water oxidation (SCWO) was also investigated. The results show that ammonia nitrogen, phenols and pyridines are main refractory intermediates. The weight of solid products at 873K and n=4 is only 3.5wt.% of the initial weight, which is lower than that after combustion. Volatile organics in solid phase have almost released at 723K and n=0. Highest yield of combustible gases was obtained at n=0, and H2 yield can reach 11.81mol/kg at 873K. Furthermore, the combination of SCWG at 723K and SCWO at 873K with a total n=1 is feasible for its good effluent quality and low operation costs. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. Biological efficacy and toxic effect of emergency water disinfection process based on advanced oxidation technology.

    Science.gov (United States)

    Tian, Yiping; Yuan, Xiaoli; Xu, Shujing; Li, Rihong; Zhou, Xinying; Zhang, Zhitao

    2015-12-01

    An innovative and removable water treatment system consisted of strong electric field discharge and hydrodynamic cavitation based on advanced oxidation technologies was developed for reactive free radicals producing and waterborne pathogens eliminating in the present study. The biological efficacy and toxic effects of this advanced oxidation system were evaluated during water disinfection treatments. Bench tests were carried out with synthetic microbial-contaminated water, as well as source water in rainy season from a reservoir of Dalian city (Liaoning Province, China). Results showed that high inactivation efficiency of Escherichia coli (>5 log) could be obtained for synthetic contaminated water at a low concentration (0.5-0.7 mg L(-1)) of total oxidants in 3-10 s. The numbers of wild total bacteria (108 × 10(3) CFU mL(-1)) and total coliforms (260 × 10(2) MPN 100 mL(-1)) in source water greatly reduced to 50 and 0 CFU mL(-1) respectively after treated by the advanced oxidation system, which meet the microbiological standards of drinking water, and especially that the inactivation efficiency of total coliforms could reach 100%. Meanwhile, source water qualities were greatly improved during the disinfection processes. The values of UV254 in particular were significantly reduced (60-80%) by reactive free radicals. Moreover, the concentrations of possible disinfection by-products (formaldehyde and bromide) in treated water were lower than detection limits, indicating that there was no harmful effect on water after the treatments. These investigations are helpful for the ecotoxicological studies of advanced oxidation system in the treatments of chemical polluted water or waste water. The findings of this work suggest that the developed water treatment system is ideal in the acute phases of emergencies, which also could offer additional advantages over a wide range of applications in water pollution control.

  16. Biological processes for concentrating trace elements from uranium mine waters. Technical completion report

    Energy Technology Data Exchange (ETDEWEB)

    Brierley, C.L.; Brierley, J.A.

    1981-12-01

    Waste water from uranium mines in the Ambrosia Lake district near Grants, New Mexico, USA, contains uranium, selenium, radium and molybdenum. The Kerr-McGee Corporation has a novel treatment process for waters from two mines to reduce the concentrations of the trace contaminants. Particulates are settled by ponding, and the waters are passed through an ion exchange resin to remove uranium; barium chloride is added to precipitate sulfate and radium from the mine waters. The mine waters are subsequently passed through three consecutive algae ponds prior to discharge. Water, sediment and biological samples were collected over a 4-year period and analyzed to assess the role of biological agents in removal of inorganic trace contaminants from the mine waters. Some of the conclusions derived from this study are: (1) The concentrations of soluble uranium, selenium and molybdenum were not diminished in the mine waters by passage through the series of impoundments which constituted the mine water treatment facility. Uranium concentrations were reduced but this was due to passage of the water through an ion exchange column. (2) The particulate concentrations of the mine water were reduced at least ten-fold by passage of the waters through the impoundments. (3) The sediments were anoxic and enriched in uranium, molybdenum and selenium. The deposition of particulates and the formation of insoluble compounds were proposed as mechanisms for sediment enrichment. (4) The predominant algae of the treatment ponds were the filamentous Spirogyra and Oscillatoria, and the benthic alga, Chara. (5) Adsorptive processes resulted in the accumulation of metals in the algae cells. (6) Stimulation of sulfate reduction by the bacteria resulted in retention of molybdenum, selenium, and uranium in sediments. 1 figure, 16 tables.

  17. Characterisation and treatment of VOCs in process water from upgrading facilities for compressed biogas (CBG).

    Science.gov (United States)

    Nilsson Påledal, S; Arrhenius, K; Moestedt, J; Engelbrektsson, J; Stensen, K

    2016-02-01

    Compression and upgrading of biogas to vehicle fuel generates process water, which to varying degrees contains volatile organic compounds (VOCs) originating from the biogas. The compostion of this process water has not yet been studied and scientifically published and there is currently an uncertainty regarding content of VOCs and how the process water should be managed to minimise the impact on health and the environment. The aim of the study was to give an overview about general levels of VOCs in the process water. Characterisation of process water from amine and water scrubbers at plants digesting waste, sewage sludge or agricultural residues showed that both the average concentration and composition of particular VOCs varied depending on the substrate used at the biogas plant, but the divergence was high and the differences for total concentrations from the different substrate groups were only significant for samples from plants using waste compared to residues from agriculture. The characterisation also showed that the content of VOCs varied greatly between different sampling points for same main substrate and between sampling occasions at the same sampling point, indicating that site-specific conditions are important for the results which also indicates that a number of analyses at different times are required in order to make an more exact characterisation with low uncertainty. Inhibition of VOCs in the anaerobic digestion (AD) process was studied in biomethane potential tests, but no inhibition was observed during addition of synthetic process water at concentrations of 11.6 mg and 238 mg VOC/L. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. Understanding the Role of Water on Electron-Initiated Processes and Radical Chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Garrett, Bruce C [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Colson, Steven D [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Dixon, David A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Laufer, Allan H [US Department of Energy Office of Science Office of Basic Energy Sciences; Ray, Douglas [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2003-06-10

    On September 26–28, 2002, a workshop entitled “Understanding the Role of Water on Electron-Initiated Processes and Radical Chemistry” was held to assess new research opportunities in electron-driven processes and radical chemistry in aqueous systems. Of particular interest was the unique and complex role that the structure of water plays in influencing these processes. Novel experimental and theoretical approaches to solving long-standing problems in the field were explored. A broad selection of participants from universities and the national laboratories contributed to the workshop, which included scientific and technical presentations and parallel sessions for discussions and report writing.

  19. Behavior of hydrogen atoms in boron films during H{sub 2} and He glow discharge and thermal desorption

    Energy Technology Data Exchange (ETDEWEB)

    Tsuzuki, K.; Natsir, M.; Inoue, N. [and others

    1995-09-01

    Hydrogen absorption and desorption characteristics in boron films deposited on a graphite liner have been studied. Number of hydrogen atoms absorbed in the films is estimated from a decrease in hydrogen pressure during a hydrogen glow discharge. It was 1.9 x 10{sup 17} atoms/cm{sup 2} in the 1 hour discharge after an evacuation of H atoms contained in the original boron films by thermal desorption. Hydrogen atoms were absorbed continuously without saturation for 3 hours during the discharge. Number of H atoms absorbed reached to 2.6 x 10{sup 17} atoms/cm{sup 2} at 3 hour. A discharge in helium was carried out to investigate H desorption characteristics from hydrogen implanted boron films. It was verified that reactivity for hydrogen absorption was recovered after the He discharge. Hydrogen atoms were accumulated in the films by repetition of alternate He and H{sub 2} discharge. Thermal desorption experiments have been carried out by raising the liner temperature up to 500degC for films after 1 hour, 3 hours hydrogen discharge and 6 times repetition of H{sub 2}/He discharges. Most of H atoms in the films were desorbed for all these cases. The slow absorption process was confirmed through the thermal desorption experiments. (author).

  20. Kinetics of Cation and Oxyanion Adsorption and Desorption on Ferrihydrite: Roles of Ferrihydrite Binding Sites and a Unified Model

    Energy Technology Data Exchange (ETDEWEB)

    Tian, Lei [School of Environment and Energy, South China University of Technology, Guangzhou, Guangdong 510006, People’s Republic of China; The Key Lab of Pollution Control and Ecosystem Restoration in Industry; Shi, Zhenqing [School of Environment and Energy, South China University of Technology, Guangzhou, Guangdong 510006, People’s Republic of China; The Key Lab of Pollution Control and Ecosystem Restoration in Industry; Lu, Yang [School of Environment and Energy, South China University of Technology, Guangzhou, Guangdong 510006, People’s Republic of China; The Key Lab of Pollution Control and Ecosystem Restoration in Industry; Dohnalkova, Alice C. [Environmental; Lin, Zhang [School of Environment and Energy, South China University of Technology, Guangzhou, Guangdong 510006, People’s Republic of China; The Key Lab of Pollution Control and Ecosystem Restoration in Industry; Dang, Zhi [School of Environment and Energy, South China University of Technology, Guangzhou, Guangdong 510006, People’s Republic of China; The Key Lab of Pollution Control and Ecosystem Restoration in Industry

    2017-08-29

    Understanding the kinetics of toxic ion reactions with ferrihydrite is crucial for predicting the dynamic behavior of contaminants in soil environments. In this study, the kinetics of As(V), Cr(VI), Cu, and Pb adsorption and desorption on ferrihydrite were investigated with a combination of laboratory macroscopic experiments, microscopic investigation and mechanistic modeling. The rates of As(V), Cr(VI), Cu, and Pb adsorption and desorption on ferrihydrite, as systematically studied using a stirred-flow method, was highly dependent on the reaction pH and metal concentrations and varied significantly among four metals. Spherical aberration-corrected scanning transmission electron microscopy (Cs-STEM) showed, at sub-nano scales, all four metals were distributed within the ferrihydrite particle aggregates homogeneously after adsorption reactions, with no evidence of surface diffusion-controlled processes. Based on experimental results, we developed a unifying kinetics model for both cation and oxyanion adsorption/desorption on ferrihydrite based on the mechanistic-based equilibrium model CD-MUSIC. Overall, the model described the kinetic results well, and we quantitatively demonstrated how the equilibrium properties of the cation and oxyanion binding to various ferrihydrite sites affected the adsorption and desorption rates. Our results provided a unifying quantitative modeling method for the kinetics of both cation and oxyanion adsorption/desorption on iron minerals.

  1. Study of Adsorption and Desorption Performances of Zr-Based Metal–Organic Frameworks Using Paper Spray Mass Spectrometry

    Science.gov (United States)

    Wang, Xiaoting; Chen, Ying; Zheng, Yajun

    2017-01-01

    The dynamic pore systems and high surface areas of flexible metal–organic framework materials make them excellent candidates to be used in different kinds of adsorption processes. However, the adsorption and desorption behaviors of therapeutic drugs on metal–organic frameworks in solution are not fully developed. Here, we systematically investigated the adsorption and desorption behaviors of a typical therapeutic drug, verapamil, over several Zr-based metal–organic frameworks [e.g., Zr-FUM, UiO-66(Zr), UiO-66(Zr)-NH2 and UiO-66(Zr)-2COOH] as well as ZrO2 in an acetonitrile solution by using paper spray mass spectrometry. In contrast to other materials, UiO-66(Zr)-2COOH demonstrated a superior adsorption performance to verapamil due to their strong acid-base and/or hydrogen-bond interactions, and the adsorption process fitted well with the pseudo-second-order kinetic model. As verapamil-adsorbed materials were used for desorption experiments, ZrO2 demonstrated the most favorable desorption performance, whereas UiO-66(Zr)-2COOH yielded the poorest desorption capability. These Zr-based materials had also been coated at the surface with filter papers for the analysis of various drugs and proteins in the process of paper spray mass spectrometry. The results demonstrated that among the studied materials, ZrO2-coated paper gave the most favorable desorption performance as a pure drug solution, whereas the paper from UiO-66(Zr) demonstrated the optimal capability in the analyses of therapeutic drugs in a complex matrix (e.g., blood) and a protein (e.g., myoglobin). PMID:28773131

  2. Impact of recycling filter backwash water on organic removal in coagulation-sedimentation processes.

    Science.gov (United States)

    Gottfried, A; Shepard, A D; Hardiman, K; Walsh, M E

    2008-11-01

    The overall purpose of this research was to examine the impacts of filter backwash water (FBWW) and membrane backwash water (MBWW) recycles on water quality in coagulation-sedimentation processes. Specifically, the impact of recycling 5 or 10% by volume of FBWW and MBWW with surface water on the removal of natural organic matter (NOM) was evaluated at bench-scale using a standard jar-test apparatus and measurement of specific water quality parameters including total organic carbon (TOC), dissolved organic carbon (DOC), UV254, turbidity, total aluminum and zeta potential. The results of jar test conducted on a source water with a specific UV absorbance (SUVA) value within the range of 2-4 mg/Lm showed a significantly higher removal of DOC from the raw water that was blended with 5 and 10% by volume of FBWW as compared to control trials where backwash water was not added. Increasing rates of MBWW that did not contain destabilized hydroxide precipitates did not significantly change DOC concentrations in the settled water samples as compared to the control trials. For source waters that are characterized as having low turbidity with medium SUVA values, these results could hold particular significance for plants that have reached treatment ceilings in terms of dissolved NOM removal using conventional coagulation designs.

  3. Anaerobic Digestion of the Organic Fraction of Municipal Solid Waste With Recirculation of Process Water

    DEFF Research Database (Denmark)

    Hartmann, H.; Angelidaki, Irini; Ahring, Birgitte Kiær

    2001-01-01

    A new concept of a wet anaerobic digestion treatment of the organic fraction of municipal solid waste (OFMSW) is investigated. Once the waste is diluted with water, the entire liquid fraction of the effluent is recirculated and used as process water for dilution of the waste. This enables a well......-mixed process without additional water supply. A methane yield of 400 and 445 ml/gVS from OFMSW was achieved in batch and reactor experiments, respectively. Reactor performance with 15 days retention time and an organic loading rate of 4.5 gVS/ld was stable with low VFA concentrations and a VS reduction of 70......-80% when treating 100% OFMSW, diluted by 1:5. Recirculation of a larger fraction of the effluent makes removal of ammonia necessary in order to avoid inhibition of the process. The present process did not show degradation of the plasticizer DEHP (bis-2-ethylhexyl-phthalate) under thermophilic conditions...

  4. Cesium sorption and desorption on selected Los Alamos soils

    Energy Technology Data Exchange (ETDEWEB)

    Kung, K.S.; Chan, J.; Longmire, P.; Fowler, M.

    1995-08-01

    Laboratory experiments were conducted to evaluate the sorptivity of cesium onto Los Alamos soils under controlled experimental conditions. Four soil profiles were collected and each soil profile which is broken into layers according to previously identified soil horizons were studied. Batch sorption isotherms were studied to quantify the chemical reactivity of each soil horizon toward cesium ion. Radioactive cesium-137 was used as sorbent and gamma counting was used to quantify the amount of sorption. Desorption experiments were conducted after the sorption experiments. Batch desorption isotherms were studied to quantify the desorption of presorbed cesium from these Los Alamos soils. This study suggests cesium may sorb strongly and irreversibly on most Los Alamos soils. The amount of cesium sorption and desorption is possibly related to the clay content of the soil sample since subsurface sample has a higher clay content than that of surface sample.

  5. Challenges and Alternatives in Tsunami Water Levels Processing in NOAA/NCEI-CO Global Water-Level Data Repository

    Science.gov (United States)

    Mungov, G.; Dunbar, P. K.; Stroker, K. J.; Sweeney, A.

    2016-12-01

    The National Oceanic and Atmospheric Administration (NOAA) National Centers for Environmental Information is data repository for high-resolution, integrated water-level data to support tsunami research, risk assessment and mitigation to protect life and property damages along the coasts. NCEI responsibilities include, but are not limited to process, archiv and distribut and coastal water level data from different sourcesg tsunami and storm-surge inundation, sea-level change, climate variability, etc. High-resolution data for global historical tsunami events are collected by the Deep-ocean Assessment and Reporting of Tsunami (DART®) tsunameter network maintained by NOAA's National Data Buoy Center NDBC, coastal tide-gauges maintained by NOAA's Center for Operational Oceanographic Products and Services (CO-OPS) and Tsunami Warning Centers, historic marigrams and images, bathymetric data, and from other national and international sources. NCEI-CO water level database is developed in close collaboration with all data providers along with NOAA's Pacific Marine Environmental Laboratory. We outline here the present state in water-level data processing regarding the increasing needs for high-precision, homogeneous and "clean" tsunami records from data different sources and different sampling interval. Two tidal models are compared: the Mike Foreman's improved oceanographic model (2009) and the Akaike Bayesian Information Criterion approach applied by Tamura et al. (1991). The effects of filtering and the limits of its application are also discussed along with the used method for de-spiking the raw time series.

  6. A new sensitive method for the quantification of glyoxal and methylglyoxal in snow and ice by stir bar sorptive extraction and liquid desorption-HPLC-ESI-MS.

    Science.gov (United States)

    Müller-Tautges, Christina; Eichler, Anja; Schwikowski, Margit; Hoffmann, Thorsten

    2014-04-01

    In this study, the development of a new sensitive method for the analysis of alpha-dicarbonyls glyoxal (G) and methylglyoxal (MG) in environmental ice and snow is presented. Stir bar sorptive extraction with in situ derivatization and liquid desorption (SBSE-LD) was used for sample extraction, enrichment, and derivatization. Measurements were carried out using high-performance liquid chromatography coupled to electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS). As part of the method development, SBSE-LD parameters such as extraction time, derivatization reagent, desorption time and solvent, and the effect of NaCl addition on the SBSE efficiency as well as measurement parameters of HPLC-ESI-MS/MS were evaluated. Calibration was performed in the range of 1-60 ng/mL using spiked ultrapure water samples, thus incorporating the complete SBSE and derivatization process. 4-Fluorobenzaldehyde was applied as internal standard. Inter-batch precision was ice core from Upper Grenzgletscher (Monte Rosa massif, Switzerland). Resulting concentrations were 0.085-16.3 ng/mL for G and 0.126-3.6 ng/mL for MG. Concentrations of G and MG in snow were 1-2 orders of magnitude higher than in ice core samples. The described method represents a simple, green, and sensitive analytical approach to measure G and MG in aqueous environmental samples.

  7. Advanced Signal Processing for High Temperatures Health Monitoring of Condensed Water Height in Steam Pipes

    Science.gov (United States)

    Lih, Shyh-Shiuh; Bar-Cohen, Yoseph; Lee, Hyeong Jae; Takano, Nobuyuki; Bao, Xiaoqi

    2013-01-01

    An advanced signal processing methodology is being developed to monitor the height of condensed water thru the wall of a steel pipe while operating at temperatures as high as 250deg. Using existing techniques, previous study indicated that, when the water height is low or there is disturbance in the environment, the predicted water height may not be accurate. In recent years, the use of the autocorrelation and envelope techniques in the signal processing has been demonstrated to be a very useful tool for practical applications. In this paper, various signal processing techniques including the auto correlation, Hilbert transform, and the Shannon Energy Envelope methods were studied and implemented to determine the water height in the steam pipe. The results have shown that the developed method provides a good capability for monitoring the height in the regular conditions. An alternative solution for shallow water or no water conditions based on a developed hybrid method based on Hilbert transform (HT) with a high pass filter and using the optimized windowing technique is suggested. Further development of the reported methods would provide a powerful tool for the identification of the disturbances of water height inside the pipe.

  8. Water ecosystem service function assessment based on eco-hydrological process in Luanhe Basin,China

    Science.gov (United States)

    Zhang, C.; Hao, C.; Qin, T.; Wang, G.; Weng, B.

    2012-12-01

    At present, ecological water are mainly occupied by a rapid development of social economic and population explosion, which seriously threat the ecological security and water security in watershed and regional scale. Due to the lack of a unified standard of measuring the benefit of water resource, social economic and ecosystem, the water allocation can't take place in social economic and ecosystem. The function which provided by water in terrestrial, aquatic and social economic system can be addressed through water ecosystem service function research, and it can guide the water allocation in water resource management. The function which provided by water in terrestrial, aquatic and social economic system can be addressed through water ecosystem service function research, and it can guide the water allocation in water resource management. Throughout the researches of water ecosystem service, a clear identification of the connection of water ecosystem service function has not been established, and eco-economic approach can't meet the practical requirement of water allocation. Based on "nature-artificiality" dual water cycle theory and eco-hydrological process, this paper proposes a connection and indicator system of water ecosystem service function. In approach, this paper establishes an integrated assessment approach through prototype observation technology, numerical simulation, physical simulation and modern geographic information technology. The core content is to couple an eco-hydrological model, which involves the key processes of distributed hydrological model (WEP), ecological model (CLM-DGVM), in terms of eco-hydrological process. This paper systematically evaluates the eco-hydrological process and evolution of Luanhe Basin in terms of precipitation, ET, runoff, groundwater, ecosystem's scale, form and distribution. According to the results of eco-hydrological process, this paper assesses the direct and derived service function. The result indicates that the

  9. Synthesis and Review: African Environmental Processes and Water-Cycle Dynamics

    Science.gov (United States)

    Ichoku, Charles; Adegoke, Jimmy

    2016-01-01

    Africa's vast landmass harbors a variety of physical processes that affect the environment and the water cycle. This focus issue on the "African Environmental Processes and Water-Cycle Dynamics" contains eight articles that address these phenomena from different but complementary perspectives. Fires used for agricultural and related purposes play a major role in land-cover change, surface albedo modifications, and smoke emission; all of which affect the environment and the water cycle in different ways. However, emissions of aerosols and trace gases are not restricted to fires, but also emanate from other natural and human activities. The African water cycle undergoes significant perturbations that are attributable to several factors, including the aforesaid environmental processes. These changes in the water cycle have produced severe drought and flooding events in recent decades that affect societal wellbeing across sub-Saharan Africa. The combined effects of the environmental processes and water-cycle dynamics affect and are affected by climate variability and can be propagated beyond the continent. Future studies should utilize the wealth of observations and modeling tools that are constantly improving to clearly elucidate the interrelationships between all of these phenomena for the benefit of society.

  10. Modeling and Understanding BOD Removal Processes in Free-Water Surface Constructed Wetlands

    Science.gov (United States)

    Deng, Z.

    2016-12-01

    Free-water surface constructed wetlands have proven to be effective systems for removal of various pollutants in wastewater and agricultural drainage water. Modeling tools are needed for understanding the processes and mechanisms responsible for the removal of pollutants and for the design of new constructed wetlands. This paper presents a new model for mimicking the processes and mechanisms controlling the removal of BOD (biochemical oxygen demand) in free-water surface constructed wetlands. The processes and mechanisms, simulated in the model, include advection, dispersion, diffusion, monod kinetics of bacterial growth, water gains (via precipitation) and losses (evaporation and seepage) and mass exchange between water column and root layers of a wetland. A novel feature of the new model is the incorporation of a dynamic diffusive root-zone. Sensitivity analysis of the model input vaiables indicates that the BOD removal in free water surface constructed wetlands is most sensitive to the biological removal process of BOD in the root zone, controlled by acetic acid and anaerobic bacteria in root zone, and the flow velocity (controlling mean hydraulic residence time) and organic carbon in the water column. The application of the new model is demonstrated through two case studies involving two distinct constructed wetlands with one (Gustine Wetland) for treatment of secondary wastewater located in the USA and another (Lake Manzala Engineered Wetland) for treatment of agricultural drainage water in Egypt. The model is relatively simple yet effective, as evidenced by the high coefficient of determination of 0.73 - 0.99 for the Gustine Wetland and 0.98 for Manzala Wetland. The model is a reliable and efficient tool for designing constructed wetlands and for understanding effects of various processes and mechanisms on the treatment efficiency of wastewater in constructed wetlands.

  11. Spatial Pattern of Great Lakes Estuary Processes from Water Quality Sensing and Geostatistical Methods

    Science.gov (United States)

    Xu, W.; Minsker, B. S.; Bailey, B.; Collingsworth, P.

    2014-12-01

    Mixing of river and lake water can alter water temperature, conductivity, and other properties that influence ecological processes in freshwater estuaries of the Great Lakes. This study uses geostatistical methods to rapidly visualize and understand water quality sampling results and enable adaptive sampling to remove anomalies and explore interesting phenomena in more detail. Triaxus, a towed undulating sensor package, was used for collecting various physical and biological water qualities in three estuary areas of Lake Michigan in Summer 2011. Based on the particular sampling pattern, data quality assurance and quality control (QA/QC) processes, including sensor synchronization, upcast and downcast separation, and spatial outlier removal are first applied. An automated kriging interpolation approach that considers trend and anisotropy is then proposed to estimate data on a gridded map for direct visualization. Other methods are explored with the data to gain more insights on water quality processes. Local G statistics serve as a supplementary tool to direct visualization. The method identifies statistically high value zones (hot spots) and low value zones (cold spots) in water chemistry across the estuaries, including locations of water sources and intrusions. In addition, chlorophyll concentration distributions are different among sites. To further understand the interactions and differences between river and lake water, K-means clustering algorithm is used to spatially cluster the water based on temperature and specific conductivity. Statistical analysis indicates that clusters with significant river water can be identified from higher turbidity, specific conductivity, and chlorophyll concentrations. Different ratios between zooplankton biomass and density indicate different zooplankton structure across clusters. All of these methods can contribute to improved near real-time analysis of future sampling activity.

  12. Study on hydrogen absorption/desorption properties of uranium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Ito, Hiroshi; Yamaguchi, Kenji; Yamawaki, Michio [Tokyo Univ., Tokai, Ibaraki (Japan). Nuclear Engineering Research Lab.

    1996-10-01

    Hydrogen absorption/desorption properties of two U-Mn intermetallic compounds, U{sub 6}Mn and UMn{sub 2}, were investigated. U{sub 6}Mn absorbed hydrogen and the hydrogen desorption pressure of U{sub 6}Mn obtained from this experiment was higher than that of U, which was considered to be the effect of alloying, whereas UMn{sub 2} was not observed to absorb hydrogen up to 50 atm at room temperature. (author)

  13. Desorption by Femtosecond Laser Pulses : An Electron-Hole Effect?

    OpenAIRE

    D. M., NEWNS; T. F., HEINZ; J. A., MISEWICH; IBM Research Division, T. J. Watson Research Center; IBM Research Division, T. J. Watson Research Center; IBM Research Division, T. J. Watson Research Center

    1992-01-01

    Desorption of molecules from metal surfaces induced by femtosecond visible laser pulses has been reported. Since the lattice temperature rise is insufficient to explain desorption, an electronic mechanism is clearly responsible. It is shown that a theory based on direct coupling between the center-of-mass degree of freedom of the adsorbate and the electron-hole excitations of the substrate provides a satisfactory explanation of the various experimental findings.

  14. Drivers of dissolved organic carbon export in a subarctic catchment: Importance of microbial decomposition, sorption-desorption, peatland and lateral flow.

    Science.gov (United States)

    Tang, Jing; Yurova, Alla Y; Schurgers, Guy; Miller, Paul A; Olin, Stefan; Smith, Benjamin; Siewert, Matthias B; Olefeldt, David; Pilesjö, Petter; Poska, Anneli

    2018-05-01

    Tundra soils account for 50% of global stocks of soil organic carbon (SOC), and it is expected that the amplified climate warming in high latitude could cause loss of this SOC through decomposition. Decomposed SOC could become hydrologically accessible, which increase downstream dissolved organic carbon (DOC) export and subsequent carbon release to the atmosphere, constituting a positive feedback to climate warming. However, DOC export is often neglected in ecosystem models. In this paper, we incorporate processes related to DOC production, mineralization, diffusion, sorption-desorption, and leaching into a customized arctic version of the dynamic ecosystem model LPJ-GUESS in order to mechanistically model catchment DOC export, and to link this flux to other ecosystem processes. The extended LPJ-GUESS is compared to observed DOC export at Stordalen catchment in northern Sweden. Vegetation communities include flood-tolerant graminoids (Eriophorum) and Sphagnum moss, birch forest and dwarf shrub communities. The processes, sorption-desorption and microbial decomposition (DOC production and mineralization) are found to contribute most to the variance in DOC export based on a detailed variance-based Sobol sensitivity analysis (SA) at grid cell-level. Catchment-level SA shows that the highest mean DOC exports come from the Eriophorum peatland (fen). A comparison with observations shows that the model captures the seasonality of DOC fluxes. Two catchment simulations, one without water lateral routing and one without peatland processes, were compared with the catchment simulations with all processes. The comparison showed that the current implementation of catchment lateral flow and peatland processes in LPJ-GUESS are essential to capture catchment-level DOC dynamics and indicate the model is at an appropriate level of complexity to represent the main mechanism of DOC dynamics in soils. The extended model provides a new tool to investigate potential interactions among

  15. Temperature dependence of CO desorption kinetics at a novel Pt-on-Au/C PEM fuel cell anode

    DEFF Research Database (Denmark)

    Pitois, A.; Pilenga, A.; Pfrang, A.

    2010-01-01

    -modified catalysts, the interactions between underlayer and overlayer materials are worthy of consideration, since they can significantly modify the intrinsic properties of the active sites. The kinetics of the CO desorption process have been discussed with regard to the CO tolerance issue at the PEM fuel cell anode.......A Pt-on-Au/C fuel cell anode catalyst has been obtained by electrochemical deposition of platinum on carbon-supported gold nanoparticles. Its composition, structure and nanoparticle size distribution have been characterised before and after the desorption experiments using microstructural...

  16. Competitive adsorption-desorption of IgM monomers-dimers on silica and modified silica surfaces.

    Science.gov (United States)

    Guha, Suvajyoti; Wayment, Joshua; Rastogi, Vinayak; Li, Mingdong; Tarlov, Michael J; Zachariah, Michael R

    2013-07-15

    Understanding competitive adsorption-desorption of proteins onto surfaces is an important area of research in food processing and biomedical engineering. Here, we demonstrate, how electrospray-differential mobility analysis that has been traditionally used for characterizing bionanoparticles, can be used for quantifying complex competitive adsorption-desorption of oligomeric proteins or multiprotein systems using monomers and dimers of IgM as a model example onto silica and modified silica surfaces. Using ES-DMA, we show that IgM dimers show a preference to stay adsorbed to different surfaces although monomers adsorb more easily and desorption rates of monomers and dimers of IgM are surface-type-dependent and are not significantly affected by shear. We anticipate that this demonstration will make ES-DMA a popular "label-free" method for studying multicomponent multi-oligomeric protein adsorption to different surfaces in the future. Published by Elsevier Inc.

  17. [Research on signal processing for water quality monitoring based on continuous spectral analysis].

    Science.gov (United States)

    Wei, Kang-lin; Chen, Ming; Wen, Zhi-yu; Xie, Yin-ke

    2014-12-01

    Based on continuous spectrum analysis, the mathematical model for spectrum signal was established. And the spectrum signal's systematic error processing method based on the invariance of the ratio of the light intensities at any two wavelengths in the range of continuous spectrum was put forward. Combined with wavelet multi-resolution filtering noise processing techniques, the background interference processing method was established based on the spectral characteristics of the measured water quality parameter. These signal processing methods were applied to our independently developed multi-parameter water quality monitoring instrument to on-line measure COD (chemical oxygen demand), six valence chromium and anionic surfactant in the normative and actual environmental water samples, and the monitoring instrument had good repeatability (10%) and high accuracy (±10%) to meet the technical requirements of national environmental protection standards, which was verified by the contrast experiment with China national standard analysis method for determination of the three water quality parameter. The results showed that the researched signal processing methods were able to effectively reduce the spectrum signal's systematic error and the interference from noise and background, which was very important to improve the water quality monitoring instrument's technical function.

  18. Hydrodynamic properties of sedimentation particles of decantation process in recovery of secondary water

    Directory of Open Access Journals (Sweden)

    G. V. Kalashnikovdoctor

    2016-01-01

    Full Text Available The water management is the important component in industrial sphere of everyone sugar beet a factory. It on the complexity and specific water consumption has no analogues among other food enterprises. At productivity sugar beet a factory on a beet 9 thou-sand т in day is required for a washing of a beet the big specific charge of water and it is necessary nearby 60 thousand т waters. In this connection the big attention is given clearing of transporter-washing waters that allows to use repeatedly her for a washing of a beet, and also to carry out better clearing secondary waters. On the basis of studying technology of clearing of secondary waters it is carried out the analysis of research of process of gravitational sedimentation of particles at the constrained movement. Sedimentation of firm particles in suspensions under action of gravities and centrifugal forces, mechanical hashing in liquid environments is connected with movement of firm bodies in liquids. At movement of a body in a liquid there is a resistance which depends on a mode of movement and the form of a streamline body. In processes of sedimentation the weighed particle moves to liquids under action of various forces: gravities and elevating (ascending forces directed aside, return to a direction of a gravity, and also force of movement of the environment (suspension due to mechanical hashing. On the basis of modeling gravitational sedimentation of particles at the constrained movement during clearing secondary waters sugar beet manufactures and the offered design procedure speed of sedimentation of particles depending on presence of a disperse phase and Reynolds's variable number is certain at various diameters of besieged particles. It is analysed the mechanism of gravitational sedimentation at the constrained movement and results of calculation in the form of schedules of change of function of the attitude of speeds are resulted at the constrained and summary movement from a

  19. Water adsorption in hydrophilic zeolites: experiment and simulation

    OpenAIRE

    Castillo, Juan Manuel; Silvestre-Albero, Juaquin; Rodriguez-Reinoso, Francisco; Vlugt, Thijs J. H.; CALERO, Sofia

    2013-01-01

    We have measured experimental adsorption isotherms of water in zeolite LTA4A, and studied the regeneration process by performing subsequent adsorption cycles after degassing at different temperatures. We observed incomplete desorption at low temperatures, and cation rearrangement at successive adsorption cycles. We also developed a new molecular simulation force field able to reproduce experimental adsorption isotherms in the range of temperatures between 273 K and 374 K. Small deviations obs...

  20. Scaling back : new process does away with scaling in SAGD water

    Energy Technology Data Exchange (ETDEWEB)

    Harrison, L.

    2010-11-15

    This article presented a method to reduce scaling problems associated with the use of brackish water in steam assisted gravity drainage (SAGD) operations. Vancouver-based BioteQ Environmental Technology Inc. has developed an ion exchange process known as Sulf-IX, which can remove silica and sulphate from both SAGD-produced water and shale gas frac water. It has also developed a method that oilsand miners can use to selectively recover metals from contaminated water using established BioSulphide or ChemSulphide technologies. The recovered metals can then be sold to generate revenue. Although each of the two technologies' plants have very large footprints, they treat very large volumes of water. The two-stage Sulf-IX ion exchange process removes sulphates to very low levels using chemical resins that remove calcium, magnesium and sulphate ions from water. The process first loads calcium and magnesium cations onto a cation resin, and then uses anion resin to remove sulphate. The resins are regenerated using sulphuric acid and lime. The outputs from the process are a solid gypsum byproduct and clean water. BioteQ's process to precipitate metals dissolved in water exceeds the stringent environmental requirements at Xstrata plc's Raglan nickel mine in northern Quebec. Depending on the site, the dissolved metals that can be removed with BioteQ's processes include aluminum, antimony, arsenic, barium, cadmium, copper, cobalt, iron, lead, manganese, mercury, molybdenum, nickel, rhenium, selenium, strontium and zinc. Some of these metals are recovered because they have value, while others are removed because they are toxic. The difference between BioSulphide and ChemSulphide is the source of the sulphide. In the BioSulphide process, the sulphide is generated biologically in an anaerobic bioreactor in which bacteria generate hydrogen sulphide gas. A chemical source of sulphide, generally sodium hydrosulphide (NaHS), is used for the ChemSulphide. The rest of

  1. Adsorption-desorption behavior of atrazine on agricultural soils in China.

    Science.gov (United States)

    Yue, Lin; Ge, ChengJun; Feng, Dan; Yu, Huamei; Deng, Hui; Fu, Bomin

    2017-07-01

    Adsorption and desorption are important processes that affect atrazine transport, transformation, and bioavailability in soils. In this study, the adsorption-desorption characteristics of atrazine in three soils (laterite, paddy soil and alluvial soil) were evaluated using the batch equilibrium method. The results showed that the kinetics of atrazine in soils was completed in two steps: a "fast" adsorption and a "slow" adsorption and could be well described by pseudo-second-order model. In addition, the adsorption equilibrium isotherms were nonlinear and were well fitted by Freundlich and Langmuir models. It was found that the adsorption data on laterite, and paddy soil were better fitted by the Freundlich model; as for alluvial soil, the Langmuir model described it better. The maximum atrazine sorption capacities ranked as follows: paddy soil>alluvial soil>laterite. Results of thermodynamic calculations indicated that atrazine adsorption on three tested soils was spontaneous and endothermic. The desorption data showed that negative hysteresis occurred. Furthermore, lower solution pH value was conducive to the adsorption of atrazine in soils. The atrazine adsorption in these three tested soils was controlled by physical adsorption, including partition and surface adsorption. At lower equilibrium concentration, the atrazine adsorption process in soils was dominated by surface adsorption; while with the increase of equilibrium concentration, partition was predominant. Copyright © 2016. Published by Elsevier B.V.

  2. Adsorption and desorption characteristics of endosulfan in two typical agricultural soils in Southwest China.

    Science.gov (United States)

    Qian, Sheng; Zhu, Heng; Xiong, Bailian; Zheng, Guocan; Zhang, Jinzhong; Xu, Weihong

    2017-04-01

    Endosulfan is an organochlorine pesticide widely used in Southwest China. In this paper, the adsorption and desorption characteristics of endosulfan in two typical agricultural soils (latosol and lateritic red soil) in this area were studied. The results showed that Langmuir isothermal equation could well describe the adsorption thermodynamic characteristics of endosulfan in latosol and lateritic red soil, and the maximum adsorption capacities of α-endosulfan were 0.186 and 0.209 mg/g, while those of β-endosulfan were 0.140 and 0.148 mg/g, respectively. Endosulfan adsorption in the two soils was an exothermic physicochemical process, but dominated by physical process. The adsorption kinetic characteristics of endosulfan in the two soils could be well described by second-order kinetic equation, and the initial rate constants were 0.228 and 0.325 mg/(g min) for α-endosulfan, while those were 0.119 and 0.125 mg/(g min) for β-endosulfan, respectively. The adsorbed endosulfan in the two soils was difficult to be desorbed into the liquid phase, and showed weak desorption hysteresis. These results implied that endosulfan could be firmly adsorbed by the two soils, and their adsorption and desorption abilities may be related to the contents of soil clay and organic matter.

  3. Plant-wide (BSM2) evaluation of reject water treatment with a SHARON-Anammox process

    DEFF Research Database (Denmark)

    Volcke, Eveline; Gernaey, Krist; Vrecko, Darko

    2006-01-01

    treatment plant, reject water treatment with a combined SHARON-Anammox process seems a promising option. The simulation results indicate that significant improvements of the effluent quality of the main wastewater treatment plant can be realized. An economic evaluation of the different scenarios......In wastewater treatment plants (WWTPs) equipped with sludge digestion and dewatering systems, the reject water originating from these facilities contributes significantly to the nitrogen load of the activated sludge tanks, to which it is typically recycled. In this paper, the impact of reject water...... streams on the performance of a WWTP is assessed in a simulation study, using the Benchmark Simulation Model no. 2 (BSM2), that includes the processes describing sludge treatment and in this way allows for plant-wide evaluation. Comparison of performance of a WWTP without reject water with a WWTP where...

  4. Development of a Microfluidic Open Interface with Flow Isolated Desorption Volume for the Direct Coupling of SPME Devices to Mass Spectrometry.

    Science.gov (United States)

    Tascon, Marcos; Alam, Md Nazmul; Gómez-Ríos, Germán Augusto; Pawliszyn, Janusz

    2018-02-20

    Technologies that efficiently integrate the sampling and sample preparation steps with direct introduction to mass spectrometry (MS), providing simple and sensitive analytical workflows as well as capabilities for automation, can generate a great impact in a vast variety of fields, such as in clinical, environmental, and food-science applications. In this study, a novel approach that facilitates direct coupling of Bio-SPME devices to MS using a microfluidic design is presented. This technology, named microfluidic open interface (MOI), which operates under the concept of flow-isolated desorption volume, consists of an open-to-ambient desorption chamber (V ≤ 7 μL) connected to an ionization source. Subsequently, compounds of interest are transported to the ionization source by means of the self-aspiration process intrinsic of these interfaces. Thus, any ionization technology that provides a reliable and constant suction, such as electrospray ionization (ESI), atmospheric-pressure chemical ionization (APCI), or inductively coupled plasma ionization (ICP), can be hyphenated to MOI. Using this setup, the desorption chamber is used to release target compounds from the coating, while the isolation of the flow enables the ionization source to be continuously fed with solvent, all without the necessity of employment of additional valves. As a proof of concept, the design was applied to an ESI-MS/MS system for experimental validation. Furthermore, numerical simulations were undertaken to provide a detailed understanding of the fluid flow pattern inside the interface, then used to optimize the system for better efficiency. The analytical workflow of the developed Bio-SPME-MOI-MS setup consists of the direct immersion of SPME fibers into the matrix to extract/enrich analytes of interest within a short period of time, followed by a rinsing step with water to remove potentially adhering proteins, salts, and/or other interfering compounds. Next, the fiber is inserted into the

  5. CO desorption from a catalytic surface: elucidation of the role of steps by velocity-selected residence time measurements.

    Science.gov (United States)

    Golibrzuch, Kai; Shirhatti, Pranav R; Geweke, Jan; Werdecker, Jörn; Kandratsenka, Alexander; Auerbach, Daniel J; Wodtke, Alec M; Bartels, Christof

    2015-02-04

    Directly measuring the rate of a surface chemical reaction remains a challenging problem. For example, even after more than 30 years of study, there is still no agreement on the kinetic parameters for one of the simplest surface reactions: desorption of CO from Pt(111). We present a new experimental technique for determining rates of surface reactions, the velocity-selected residence time method, and demonstrate it for thermal desorption of CO from Pt(111). We use UV−UV double resonance spectroscopy to record surface residence times at selected final velocities of the desorbing CO subsequent to dosing with a pulsed molecular beam. Velocity selection differentiates trapping-desorption from direct scattering and removes influences on the temporal profile arising from the velocity distribution of the desorbing CO. The kinetic data thus obtained are of such high quality that bi-exponential desorption kinetics of CO from Pt(111) can be clearly seen. We assign the faster of the two rate processes to desorption from (111) terraces, and the slower rate process to sequential diffusion from steps to terraces followed by desorption. The influence of steps, whose density may vary from crystal to crystal, accounts for the diversity of previously reported (single exponential) kinetics results. Using transition-state theory, we derive the binding energy of CO to Pt(111) terraces, D(0)(terr) (Pt−CO) = 34 ± 1 kcal/mol (1.47 ± 0.04 eV) for the low coverage limit (≤0.03 ML) where adsorbate−adsorbate interactions are negligible. This provides a useful benchmark for electronic structure theory of adsorbates on metal surfaces.

  6. The Optimization-Based Design and Synthesis of Water Network for Water Management in an Industrial Process: Refinery Effluent Treatment Plant

    DEFF Research Database (Denmark)

    Sueviriyapan, Natthapong; Siemanond, Kitipat; Quaglia, Alberto

    2014-01-01

    The increasing awareness of the sustainability of water resources has become an important issue. Many process industries contribute to high water consumption and wastewater generation. Problems in industrial water management include the processing of complex contaminants in wastewater, selection......-based synthesis process for a water/wastewater treatment network design problem utilizing the framework of Quaglia et al. (2013) in order to effectively design, synthesize, and optimize an industrial water management problem using different scenarios (both existing and retrofit system design). The model...

  7. EFFICACY OF FILTRATION PROCESSES TO OBTAIN WATER CLARITY AT K EAST SPENT NUCLEAR FUEL (SNF) BASIN

    Energy Technology Data Exchange (ETDEWEB)

    DUNCAN JB

    2006-09-28

    The objective is to provide water clarity to the K East Basin via filtration processes. Several activities are planned that will challenge not only the capacity of the existing ion exchange modules to perform as needed but also the current filtration system to maintain water clarity. Among the planned activities are containerization of sludge, removal of debris, and hydrolasing the basin walls to remove contamination.

  8. A daily water balance model for representing streamflow generation process following land use change

    OpenAIRE

    Bari, M. A.; K. R. J. Smettem

    2005-01-01

    International audience; A simple conceptual water balance model representing the streamflow generation processes on a daily time step following land use change is presented. The model consists of five stores: (i) Dry, Wet and Subsurface Stores for vertical and lateral water flow, (ii) a transient Stream zone Store (iii) a saturated Goundwater Store. The soil moisture balance in the top soil Dry and Wet Stores are the most important component of the model and characterize the dynamically varyi...

  9. Modelling and automation of the process of phosphate ion removal from waste waters

    Directory of Open Access Journals (Sweden)

    L. Lupa

    2008-03-01

    Full Text Available Phosphate removal from waste waters has become an environmental necessity, since these phosphates stimulate the growth of aquatic plants and planktons and contribute to the eutrophication process in general. The physicochemical methods of phosphate ion removal are the most effective and reliable. This paper presents studies on the process of phosphate ion removal from waste waters resulting from the fertiliser industry’s use of the method of co-precipitation with iron salts and with calcium hydroxide as the neutralizing agent. The optimal process conditions were established as those that allow achievement of a maximum degree of separation of the phosphate ions. The precipitate resulting from the co-precipitation process was analysed for chemical composition and establishment of thermal and structural stability, and the aim was also to establish in which form the phosphate ions in the formed precipitate can be found. Based on these considerations, the experimental data obtained in the process of phosphate ion removal from waste waters were analysed mathematically and the equations for the dependence of the degree of phosphate separation and residual concentration versus the main parameters of the process were formulated. In this paper an automated scheme for the phosphate ion removal from waste waters by co-precipitation is presented.

  10. Benefits of Mars ISRU Regolith Water Processing: A Case Study for the NASA Evolvable Mars Campaign

    Science.gov (United States)

    Kleinhenz, Julie; Paz, Aaron; Mueller, Robert

    2016-01-01

    ISRU of Mars resources was baselined in 2009 Design Reference Architecture (DRA) 5.0, but only for Oxygen production using atmospheric CO2. The Methane (LCH4) needed for ascent propulsion of the Mars Ascent Vehicle (MAV) would need to be brought from Earth. However: Extracting water from the Martian Regolith enables the production of both Oxygen and Methane from Mars resources: Water resources could also be used for other applications including: Life support, radiation shielding, plant growth, etc. Water extraction was not baselined in DRA5.0 due to perceived difficulties and complexity in processing regolith. The NASA Evolvable Mars Campaign (EMC) requested studies to look at the quantitative benefits and trades of using Mars water ISRUPhase 1: Examined architecture scenarios for regolith water retrieval. Completed October 2015. Phase 2: Deep dive of one architecture concept to look at end-to-end system size, mass, power of a LCH4/LO2 ISRU production system

  11. Adsorption, desorption, and diffusion of k-mers on a one-dimensional lattice.

    Science.gov (United States)

    Loncarević, I; Budinski-Petković, Lj; Vrhovac, S B; Belić, A

    2009-08-01

    Kinetics of the deposition process of k -mers in the presence of desorption or/and diffusional relaxation of particles is studied by Monte Carlo method on a one-dimensional lattice. For reversible deposition of k-mers, we find that after the initial "jamming," a stretched exponential growth of the coverage theta(t) toward the steady-state value theta(eq) occurs, i.e., theta(eq)-theta(t) is proportional to exp[-(t/tau)(beta)]. The characteristic time scale tau is found to decrease with desorption probability P(des) according to a power law, tau is proportional to P(des)(-gamma), with the same exponent gamma=1.22+/-0.04 for all k-mers. For irreversible deposition with diffusional relaxation, the growth of the coverage theta(t) above the jamming limit to the closest packing limit (CPL) theta(CPL) is described by the pattern theta(CPL)-theta(t) is proportional to E(beta)[-(t/tau)(beta)], where E(beta) denotes the Mittag-Leffler function of order beta(0,1) . Similarly to the reversible case, we found that the dependence of the relaxation time tau on the diffusion probability P(dif) is consistent again with a simple power-law, i.e., tau is proportional to P(dif)(-delta). When adsorption, desorption, and diffusion occur simultaneously, coverage always reaches an equilibrium value theta(eq), which depends only on the desorption/adsorption probability ratio. The presence of diffusion only hastens the approach to the equilibrium state, so that the stretched exponential function gives a very accurate description of the deposition kinetics of these processes in the whole range above the jamming limit.

  12. Improved adsorption-desorption extraction applied to the partial characterization of the antilisterial bacteriocin produced by Carnobacterium maltaromaticum C2

    Directory of Open Access Journals (Sweden)

    F. L Tulini

    2010-06-01

    Full Text Available Bacteriocins are ribosomally produced peptides useful for food biopreservation. An improved adsorption-desorption process is proposed for the partial purification of the bacteriocin produced by the fish isolate Carnobacterium maltaromaticum C2. Analyzis of extract by SDS-PAGE indicated this method may offer an alternative to improve the yield of purification of bacteriocins.

  13. Absorption and desorption mass transfer rates in chemically enhanced reactive systems. Part II : Reverse kinetic rate parameters

    NARCIS (Netherlands)

    Hamborg, Espen S.; Versteeg, Geert F.

    2012-01-01

    The forward and reverse kinetic rate parameters have been determined for CO2 absorption and desorption mass transfer processes in aqueous 2.0 M MDEA solutions at temperatures of 298.15, 313.15, and 333.15 K and the loading of CO2 ranging from 0 to 0.8. The derived kinetic rate parameters have been

  14. NMR spectroscopy and chemometrics to evaluate different processing of coconut water.

    Science.gov (United States)

    Sucupira, N R; Alves Filho, E G; Silva, L M A; de Brito, E S; Wurlitzer, N J; Sousa, P H M

    2017-02-01

    NMR and chemometrics was applied to understand the variations in chemical composition of coconut water under different processing. Six processing treatments were applied to coconut water and analyzed: two control (with and without sulphite), and four samples thermally processed at 110°C and 136°C (with and without sulphite). Samples processed at lower temperature and without sulphite presented pink color under storage. According to chemometrics, samples processed at higher temperature exhibited lower levels of glucose and malic acid. Samples with sulphite processed at 136°C presented lower amount of sucrose, suggesting the degradation of the carbohydrates after harshest thermal treatment. Samples with sulphite and processed at lower temperature showed higher concentration of ethanol. However, no significant changes were verified in coconut water composition as a whole. Sulphite addition and the temperature processing to 136°C were effective to prevent the pinking and to maintain the levels of main organic compounds. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Standard practice for fluorescent liquid penetrant testing using the Water-Washable process

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2010-01-01

    1.1 This practice covers procedures for water-washable fluorescent penetrant examination of materials. It is a nondestructive testing method for detecting discontinuities that are open to the surface such as cracks, seams, laps, cold shuts, laminations, isolated porosity, through leaks, or lack of porosity and is applicable to in-process, final, and maintenance examination. It can be effectively used in the examination of nonporous, metallic materials, both ferrous and nonferrous, and of nonmetallic materials such as glazed or fully densified ceramics and certain nonporous plastics and glass. 1.2 This practice also provides a reference: 1.2.1 By which a fluorescent penetrant examination method using the water-washable process recommended or required by individual organizations can be reviewed to ascertain its applicability and completeness. 1.2.2 For use in the preparation of process specifications dealing with the water-washable fluorescent penetrant examination of materials and parts. Agreement by the purch...

  16. Dominant processes controlling water chemistry of the Pecos River in American southwest

    Science.gov (United States)

    Yuan, Fasong; Miyamoto, Seiichi

    2005-09-01

    Here we show an analysis of river flow and water chemistry data from eleven gauging stations along the Pecos River in eastern New Mexico and western Texas, with time spanning 1959-2002. Analysis of spatial relationship between the long-term average flow and total dissolved solids (TDS) concentration allows us to illuminate four major processes controlling river chemistry, namely saline water addition, evaporative concentration with salt gain or loss, dilution with salt gain or loss, and salt storage. Of the 10 river reaches studied, six reaches exhibit the process dominated by evaporative concentration or freshwater dilution with little change in salt load. Four reaches show considerable salt gains or losses that are induced by surface-ground water interactions. This analysis suggests that the evaporative concentration and freshwater dilution are the prevailing mechanisms, but local processes (e.g., variations in hydrologic flowpath and lithologic formation) also play an important role in regulating the hydrochemistry of the Pecos River.

  17. Enhancement of Protein and Pigment Content in Two Chlorella Species Cultivated on Industrial Process Water

    DEFF Research Database (Denmark)

    Safafar, Hamed; Uldall Nørregaard, Patrick; Ljubic, Anita

    2016-01-01

    Chlorella pyrenoidosa and Chlorella vulgaris were cultivated in pre-gasified industrial process water with high concentration of ammonia representing effluent from a local biogas plant. The study aimed to investigate the effects of growth media and cultivation duration on the nutritional composit......Chlorella pyrenoidosa and Chlorella vulgaris were cultivated in pre-gasified industrial process water with high concentration of ammonia representing effluent from a local biogas plant. The study aimed to investigate the effects of growth media and cultivation duration on the nutritional...... composition of biomass. Variations in proteins, lipid, fatty acid composition, amino acids, tocopherols, and pigments were studied. Both species grew well in industrial process water. The contents of proteins were affected significantly by the growth media and cultivation duration. Microalga Chlorella...

  18. THE SEQUENTIAL WATER TREATMENT CONTAINING MYCOESTROGENS IN PHOTOCATALYSIS AND NANOFILTRATION PROCESSES

    Directory of Open Access Journals (Sweden)

    Mariusz Dudziak

    2014-10-01

    Full Text Available The results of the study focused on the impact of membrane on the performance of the integrated system photocatalysis/nanofiltration applied to remove mycoestrogens from water are discussed in the paper. The results were compared with ones obtained during single step photocatalysis and nanofiltration processes. The subject of the study were simulated waters containing difference concentration of humic acids to which mycoestrogens were added to the concentration level 500 μg/dm3. It was shown, that the application of integrated system improved the efficiency of mycoestrogens removal in comparison with single step photocatalysis process. In case of nanofiltration, the efficiency of the treatment was comparable in both, integrated and single nanofiltration processes regardless of the membrane type applied. However, it was found that investigated membranes differ in the affinity to fouling and removal rate of inorganic compounds, what should be considered during water treatment technology development.

  19. Sediment and process water characterization in support of 300 Area North Process Pond physical soil washing test

    Energy Technology Data Exchange (ETDEWEB)

    Field, J.G.

    1994-02-18

    The sediments in the 300 Area North Process Pond are being considered for clean-up using soil washing processes. Prior to site clean-up several preliminary pilot-scale physical washing campaigns were performed by Westinghouse Hanford Company (WHC) staff in the summer of 1993. WHC used equipment that was obtained from the US Environmental Protection Agency. Specific details are found in the 300-FF-1 Physical Separations CERCLA Treatability Test Plan. Physical soil washing includes separation and proper containment of the contaminant-rich fines and residual liquid effluent and release of the coarse ``clean`` fraction, should it meet minimum performance levels for residual contaminant concentration to the site being cleaned. A goal of the demonstration is to concentrate the contaminants into {le}10% of the soil volume excavated and, therefore, to release {ge}90% of the soil back to the site as clean soil. To support interpretation of the WHC soil washing treatability study, PNL performed some sediment and process water characterization on samples taken during three major and one small campaign. This report documents particle-size distributions in various field washed piles, and chemical and gama emitting radionuclide contents as a function of particle-size distribution for the field washed sediments and contents in the spent process water. All of the particle fractions were separated by wet sieving, but two field samples were also subjected to dry sieving and attrition scrubbing followed by wet sieving.

  20. Atomistic scale nanoscratching behavior of monocrystalline Cu influenced by water film in CMP process

    Science.gov (United States)

    Shi, Junqin; Chen, Juan; Fang, Liang; Sun, Kun; Sun, Jiapeng; Han, Jing

    2018-03-01

    The effect of water film on the nanoscratching behavior of monocrystalline Cu was studied by molecular dynamics (MD) simulation. The results indicate that the friction force acting on abrasive particle increases due to the resistance of water film accumulating ahead of particle, but the water film with lubrication decreases friction force acting on Cu surface. The accumulation of water molecules around particle causes the anisotropy of ridge and the surface damage around the groove, and the water molecules remaining in the groove lead to the non-regular groove structure. The dislocation evolution displays the re-organization of the dislocation network in the nanoscratching process. The evaluation of removal efficiency shows the number of removed Cu atoms decreases with water film thickness. It is considered that an appropriate rather than a high removal efficiency should be adopted to evaluate the polishing process in real (chemical mechanical polishing) CMP. These results are helpful to reveal the polishing mechanism under the effect of water film from physical perspective, which benefits the development of ultra-precision manufacture and miniaturized components, as well as the innovation of CMP technology.

  1. [Monitoring and analysis on evolution process of rainfall runoff water quality in urban area].

    Science.gov (United States)

    Dong, Wen; Li, Huai-En; Li, Jia-Ke

    2013-02-01

    In order to find the water quality evolution law and pollution characteristics of the rainfall runoff from undisturbed to the neighborhood exit, 6 times evolution process of rainfall runoff water quality were monitored and analyzed from July to October in 2011, and contrasted the clarification efficiency of the grassland to the roof runoff rudimentarily at the same time. The research showed: 1. the results of the comparison from "undisturbed, rainfall-roof, rainfall runoff-road, rainfall-runoff the neighborhood exit runoff " showed that the water quality of the undisturbed rain was better than that from the roof and the neighborhood exist, but the road rainfall runoff water quality was the worst; 2. the average concentrations of the parameters such as COD, ammonia nitrogen and total nitrogen all exceeded the Fifth Class of the Surface Water Quality Standard except for the soluble total phosphorus from undisturbed rainfall to the neighborhood exit; 3. the runoff water quality of the short early fine days was better than that of long early fine days, and the last runoff water quality was better than that of the initial runoff in the same rainfall process; 4. the concentration reduction of the grassland was notable, and the reduction rate of the grassland which is 1.0 meter wide of the roof runoff pollutants such as COD and nitrogen reached 30%.

  2. Cold Water Vapor in the Barnard 5 Molecular Cloud

    Science.gov (United States)

    Wirstrom, E. S.; Charnley, S. B.; Persson, C. M.; Buckle, J. V.; Cordiner, M. A.; Takakuwa, S.

    2014-01-01

    After more than 30 yr of investigations, the nature of gas-grain interactions at low temperatures remains an unresolved issue in astrochemistry. Water ice is the dominant ice found in cold molecular clouds; however, there is only one region where cold ((is) approximately 10 K) water vapor has been detected-L1544. This study aims to shed light on ice desorption mechanisms under cold cloud conditions by expanding the sample. The clumpy distribution of methanol in dark clouds testifies to transient desorption processes at work-likely to also disrupt water ice mantles. Therefore, the Herschel HIFI instrument was used to search for cold water in a small sample of prominent methanol emission peaks. We report detections of the ground-state transition of o-H2O (J = 110-101) at 556.9360 GHz toward two positions in the cold molecular cloud, Barnard 5. The relative abundances of methanol and water gas support a desorption mechanism which disrupts the outer ice mantle layers, rather than causing complete mantle removal.

  3. Electrochemical Advanced Oxidation Process for Shipboard Final Purification of Filtered Black Water, Gray Water, and Bilge Water, Vol. 1

    Science.gov (United States)

    2001-08-01

    test cells (Section 9). An off-white “ crud ” was observed depositing on the working face of the cathode. This crud appeared to be a mixture of clay and...The deposition of crud on the cathodes was eliminated by replacing the white PVC Raschig rings with polyethylene rings, and a filter was added to the...surface of a fiber. This pattern suggests that an electrochemical process is controlling deposition of the precoat. BSE images of the seal-coated

  4. Phytoremediation technologies for Ni ++ by water hyacinth | Hussain ...

    African Journals Online (AJOL)

    (desorption) of Ni++, 3 M HNO3 was used. Desorption capacity was 3.71 μg/g of ash. The results of comparative study show order of nickel phytoremediation from soil to be greater than that from water by adsorption which was greater than that from water by hydroponic study. For phytoremoval of Ni++ from soil and water, ...

  5. Effect of salinity on adsorption and desorption of paraquat in Pak Phanang river sediment, Thailand.

    Science.gov (United States)

    Noicharoen, Damrongsak; Parkpian, Preeda; Shipin, Oleg V; Polprasert, Chongrak; Delaune, Ronald D; Kongchum, Manoch

    2012-01-01

    Batch experiments were conducted to study the effect of salinity (0-30 g L(-1)) on adsorption and desorption of paraquat (1, 1'-dimethyl-4, 4'-dipyridylium dichloride), one of the most widely used herbicides in the world, in sediment of Pak Phanang River Basin, Thailand. Sediments from five locations were used in the studies (two from freshwater sites and three sites under saline environment). The adsorption capacity (K(f)) of the sediments was positively correlated with CEC (r = 0.81**) and clay content (r = 0.70*). Paraquat adsorption by sediment was faster under fresh water (0 g L(-1)) versus saline conditions (10 and 20 g L(-1)). The adsorption coefficient (K(f)) at low salinity (0 g L(-1)) was 17,302 whereas the K(f) at 10 and 20 g L(-1) were 5,344 and 4,263, respectively. Paraquat desorption was greater at higher salinity, which is similar to the salinity of estuarine or seawater. Approximately 12-31 % of sorbed paraquat in fresh water and saline sediment (7.67 and 7.98 mg kg(-1)) were released when leaching with 20 g L(-1) salinity. The amount of paraquat released was in proportion to the amount sorbed. Results show that increases in salinity resulting from salt water intrusion from the lower estuary into the Pak Phanang River Basin would result in release of adsorbed paraquat from sediment into the water column.

  6. The influence of water/rock − water/clay interactions and mixing in the salinization processes of groundwater

    Directory of Open Access Journals (Sweden)

    Julien Walter

    2017-10-01

    New hydrological insights for the region: The results show that each of the two salinization paths exerts a major and different influence on the chemical signature of groundwater. Groundwater present in the crystalline bedrock naturally evolve from a recharge-type groundwater (Ca-HCO3-dominant to a type of brackish groundwater (Ca-(Na-Cl-dominant due to water/rock interactions (plagioclase weathering and mixing with deep basement fluids. Groundwater evolution in confined aquifers is dominated by water/clay interactions. The term water/clay interactions was introduced in this paper to account for a combination of processes: ion exchange and/or leaching of salt water trapped in the regional aquitard. Mixing with fossil seawater might also increase the groundwater salinity. PCA revealed that Ca2+, Sr2+, Ba2+ are highly correlated with groundwater from bedrock aquifers, while Mg2+, SiO2, K+, SO42−and HCO3− are more representative of the regional confining conditions.

  7. THERMODYNAMIC CONSIDERATIONS FOR THERMAL WATER SPLITTING PROCESSES AND HIGH TEMPERATURE ELECTROLYSIS

    Energy Technology Data Exchange (ETDEWEB)

    J. E. O' Brien

    2008-11-01

    A general thermodynamic analysis of hydrogen production based on thermal water splitting processes is presented. Results of the analysis show that the overall efficiency of any thermal water splitting process operating between two temperature limits is proportional to the Carnot efficiency. Implications of thermodynamic efficiency limits and the impacts of loss mechanisms and operating conditions are discussed as they pertain specifically to hydrogen production based on high-temperature electrolysis. Overall system performance predictions are also presented for high-temperature electrolysis plants powered by three different advanced nuclear reactor types, over their respective operating temperature ranges.

  8. System and process for efficient separation of biocrudes and water in a hydrothermal liquefaction system

    Energy Technology Data Exchange (ETDEWEB)

    Elliott, Douglas C.; Hart, Todd R.; Neuenschwander, Gary G.; Oyler, James R.; Rotness, Jr, Leslie J.; Schmidt, Andrew J.; Zacher, Alan H.

    2016-08-02

    A system and process are described for clean separation of biocrudes and water by-products from hydrothermal liquefaction (HTL) product mixtures of organic and biomass-containing feedstocks at elevated temperatures and pressures. Inorganic compound solids are removed prior to separation of biocrude and water by-product fractions to minimize formation of emulsions that impede separation. Separation may be performed at higher temperatures that reduce heat loss and need to cool product mixtures to ambient. The present invention thus achieves separation efficiencies not achieved in conventional HTL processing.

  9. Evidence on dynamic effects in the water content – water potential relation of building materials

    DEFF Research Database (Denmark)

    Scheffler, Gregor Albrecht; Plagge, Rudolf

    2008-01-01

    a series of adsorption and desorption processes. The data provides clear evidence that the water content – water potential relationship is not only dependent on the process history, but also on the process dynamics. The higher moisture potential gradients were induced, the larger was the deviation between...... static and dynamic moisture storage data and the more pronounced was the corresponding dynamic hysteresis. The paper thus provides clear experimental evidence on dynamic effects in the water content – water potential relation of building materials. By that, data published by previous authors as Topp et...... the required material functions, i.e. the moisture storage characteristic and the liquid water conductivity, from measured basic properties. The current state of the art in material modelling as well as the corresponding transport theory implies that the moisture transport function is unique...

  10. Application of water-assisted ultraviolet light processing on the inactivation of murine norovirus on blueberries.

    Science.gov (United States)

    Liu, Chuhan; Li, Xinhui; Chen, Haiqiang

    2015-12-02

    In this study, a novel set-up using water-assisted UV processing was developed and evaluated for its decontamination efficacy against murine norovirus (MNV-1) inoculated on fresh blueberries for both small and large-scale experimental setups. Blueberries were skin-inoculated with MNV-1 and treated for 1-5 min with UV directly (dry UV) or immersed in agitated water during UV treatment (water-assisted UV). The effect of the presence of 2% (v/v) blueberry juice or 5% crushed blueberries (w/w) in wash water was also evaluated. Results showed that water-assisted UV treatment generally showed higher efficacies than dry UV treatment. With 12,000 J/m(2) UV treatment in small-scale setup, MNV reductions of >4.32- and 2.48-log were achieved by water-assisted UV and dry UV treatments, respectively. Water-assisted UV showed similar inactivating efficacy as 10-ppm chlorine wash. No virus was detected in wash water after UV treatment or chlorine wash. MNV-1 was more easily killed on skin-inoculated blueberries compared with calyx-inoculated berries. When clear water was used as wash water in the large-scale setup, water-assisted UV treatment (UV dose of 12,000 J/m(2)) resulted in >3.20 log and 1.81 log MNV-1 reductions for skin- and calyx-inoculated berries, respectively. The presence of 2% blueberry juice in wash water decreased the decontamination efficacy of water-assisted UV and chlorine washing treatments. To improve the inactivation efficacy, the effect of combining water-assisted UV treatment with chlorine washing was also evaluated. The combined treatment had better or similar inactivation efficacy compared to water-assisted UV treatment and chlorine washing alone. Findings of this study suggest that water-assisted UV treatment could be used as an alternative to chlorine washing for blueberries and potentially for other fresh produce. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. A tool to increase information-processing capacity for consumer water meter data

    Directory of Open Access Journals (Sweden)

    Heinz E. Jacobs

    2012-06-01

    Objective: The objective of this research article was to describe the development of Swift, a locally developed software tool for analysing water meter data from an information management perspective, which engineers in the water field generally use, and to assess critically the influence of Swift on published research and industry. This article focuses on water usage and the challenge of data interchange and extraction as issues that various industries face. Method: This article presents the first detailed report on Swift. It uses a detailed knowledge review and presents and summarises the findings chronologically. Results: The water meter data flow path used to be quite simple. The risk of breaches in confidentiality was limited. Technological advances over the years have led to additional knowledge coming from the same water meter readings with subsequent research outputs. However, there are also complicated data flow paths and increased risks. Users have used Swift to analyse more than two million consumers’ water meter readings to date. Studies have culminated in 10 peer-reviewed journal articles using the data. Seven of them were in the last five years. Conclusion: Swift-based data was the basis of various research studies in the past decade. Practical guidelines in the civil engineering fraternity for estimating water use in South Africa have incorporated knowledge from these studies. Developments after 1995 have increased the information processing capacity for water meter data.

  12. Water interactions with condensed organic phases: a combined experimental and theoretical study of molecular-level processes

    Science.gov (United States)

    Johansson, Sofia M.; Kong, Xiangrui; Thomson, Erik S.; Papagiannakopoulos, Panos; Pettersson, Jan B. C.; Lovrić, Josip; Toubin, Céline

    2016-04-01

    Water uptake on aerosol particles modifies their chemistry and microphysics with important implications for air quality and climate. A large fraction of the atmospheric aerosol consists of organic aerosol particles or inorganic particles with condensed organic components. Here, we combine laboratory studies using the environmental molecular beam (EMB) method1 with molecular dynamics (MD) simulations to characterize water interactions with organic surfaces in detail. The over-arching aim is to characterize the mechanisms that govern water uptake, in order to guide the development of physics-based models to be used in atmospheric modelling. The EMB method enables molecular level studies of interactions between gases and volatile surfaces at near ambient pressure,1 and the technique may provide information about collision dynamics, surface and bulk accommodation, desorption and diffusion kinetics. Molecular dynamics simulations provide complementary information about the collision dynamics and initial interactions between gas molecules and the condensed phase. Here, we focus on water interactions with condensed alcohol phases that serve as highly simplified proxies for systems in the environment. Gas-surface collisions are in general found to be highly inelastic and result in efficient surface accommodation of water molecules. As a consequence, surface accommodation of water can be safely assumed to be close to unity under typical ambient conditions. Bulk accommodation is inefficient on solid alcohol and the condensed materials appear to produce hydrophobic surface structures, with limited opportunities for adsorbed water to form hydrogen bonds with surface molecules. Accommodation is significantly more efficient on the dynamic liquid alcohol surfaces. The results for n-butanol (BuOH) are particularly intriguing where substantial changes in water accommodation taking place over a 10 K interval below and above the BuOH melting point.2 The governing mechanisms for the

  13. Rapid removal of fine particles from mine water using sequential processes of coagulation and flocculation

    Energy Technology Data Exchange (ETDEWEB)

    Jang, M.; Lee, H.J.; Shim, Y. [Korean Mine Reclamation Corporation MIRECO, Seoul (Republic of Korea)

    2010-07-01

    The processes of coagulation and flocculation using high molecular weight long-chain polymers were applied to treat mine water having fine flocs of which about 93% of the total mass was less than 3.02 {mu} m, representing the size distribution of fine particles. Six different combinations of acryl-type anionic flocculants and polyamine-type cationic coagulants were selected to conduct kinetic tests on turbidity removal in mine water. Optimization studies on the types and concentrations of the coagulant and flocculant showed that the highest rate of turbidity removal was obtained with 10 mg L{sup -1} FL-2949 (coagulant) and 12 mg L{sup -1} A333E (flocculant), which was about 14.4 and 866.7 times higher than that obtained with A333E alone and that obtained through natural precipitation by gravity, respectively. With this optimized condition, the turbidity of mine water was reduced to 0 NTU within 20 min. Zeta potential measurements were conducted to elucidate the removal mechanism of the fine particles, and they revealed that there was a strong linear relationship between the removal rate of each pair of coagulant and flocculant application and the zeta potential differences that were obtained by subtracting the zeta potential of flocculant-treated mine water from the zeta potential of coagulant-treated mine water. Accordingly, through an optimization process, coagulation-flocculation by use of polymers could be advantageous to mine water treatment, because the process rapidly removes fine particles in mine water and only requires a small-scale plant for set-up purposes owing to the short retention time in the process.

  14. Organic Micropollutants Removal from Water by Oxidation and Other Processes:QSAR Models, Decision Support System and Hybrids of Processes

    KAUST Repository

    Sudhakaran, Sairam

    2013-08-01

    The presence of organic micropollutants (OMPs) in water is of great environmental concern. OMPs such as endocrine disruptors and certain pharmaceuticals have shown alarming effects on aquatic life. OMPs are included in the priority list of contaminants in several government directorate frameworks. The low levels of OMPs concentration (ng/L to μg/L) force the use of sophisticated analytical instruments. Although, the techniques to detect OMPs are progressing, the focus of current research is only on limited, important OMPs due to the high amount of time, cost and effort involved in analyzing them. Alternatively, quantitative structure activity relationship (QSAR) models help to screen processes and propose appropriate options without considerable experimental effort. QSAR models are well-established in regulatory bodies as a method to screen toxic chemicals. The goal of the present thesis was to develop QSAR models for OMPs removal by oxidation. Apart from the QSAR models, a decision support system (DSS) based on multi-criteria analysis (MCA) involving socio-economic-technical and sustainability aspects was developed. Also, hybrids of different water treatment processes were studied to propose a sustainable water treatment train for OMPs removal. In order to build the QSAR models, the ozone/hydroxyl radical rate constants or percent removals of the OMPs were compiled. Several software packages were used to 5 compute the chemical properties of OMPs and perform statistical analyses. For DSS, MCA was used since it allows the comparison of qualitative (non-monetary, non-metric) and quantitative criteria (e.g., costs). Quadrant plots were developed to study the hybrid of natural and advanced water treatment processes. The QSAR models satisfied both chemical and statistical criteria. The DSS resulted in natural treatment and ozonation as the preferred processes for OMPs removal. The QSAR models can be used as a screening tool for OMPs removal by oxidation. Moreover, the

  15. Greenhouse gas emissions from alternative water supply processes in southern California, USA

    Science.gov (United States)

    Schneider, A.; Townsend-Small, A.

    2012-12-01

    Burgeoning population centers and declining hydrological resources have encouraged the development of alternative water treatment systems, including desalination and wastewater recycling. These processes currently provide potable water for millions of people and assist in satisfying agricultural and landscaping irrigation demands. There are a variety of alternative water production methods in place, and while they help to reduce the demands placed on aquifers, during their operation they are also significant sources of greenhouse gases. The environmental advantages of these alternative water production methods need to be carefully weighed against their energy footprints and greenhouse gas emissions profiles. This study measured the greenhouse gas emissions of a wastewater treatment and recycling facility in Orange County, California to get a more complete picture of the carbon footprint of the plant. We measured atmospheric emissions of CO2, CH4, and N2O throughout the water recycling process and at various times of the day and week. This allowed us to assemble a thorough, cross-sectional profile of greenhouse gas emissions from the facility. We then compared the measured emissions of the treatment plant to the modeled emissions of desalination plants in order to assess the relative carbon footprints of the two water production methods. Other water supply alternatives, including regional water importation, were also included in the comparison in order to provide a more complete understanding of the potential greenhouse gas emissions. Finally, we assessed the significance of wastewater treatment as an urban greenhouse gas source when compared to other known emissions in the region. This research offers a valuable tool for sustainable urban and regional development by providing planners with a quantified comparison of the carbon footprints of several water production options.

  16. Revised ground-water monitoring compliance plan for the 300 area process trenches

    Energy Technology Data Exchange (ETDEWEB)

    Schalla, R.; Aaberg, R.L.; Bates, D.J.; Carlile, J.V.M.; Freshley, M.D.; Liikala, T.L.; Mitchell, P.J.; Olsen, K.B.; Rieger, J.T.

    1988-09-01

    This document contains ground-water monitoring plans for process-water disposal trenches located on the Hanford Site. These trenches, designated the 300 Area Process Trenches, have been used since 1973 for disposal of water that contains small quantities of both chemicals and radionuclides. The ground-water monitoring plans contained herein represent revision and expansion of an effort initiated in June 1985. At that time, a facility-specific monitoring program was implemented at the 300 Area Process Trenches as part of a regulatory compliance effort for hazardous chemicals being conducted on the Hanford Site. This monitoring program was based on the ground-water monitoring requirements for interim-status facilities, which are those facilities that do not yet have final permits, but are authorized to continue interim operations while engaged in the permitting process. The applicable monitoring requirements are described in the Resource Conservation and Recovery Act (RCRA), 40 CFR 265.90 of the federal regulations, and in WAC 173-303-400 of Washington State's regulations (Washington State Department of Ecology 1986). The program implemented for the process trenches was designed to be an alternate program, which is required instead of the standard detection program when a facility is known or suspected to have contaminated the ground water in the uppermost aquifer. The plans for the program, contained in a document prepared by the US Department of Energy (USDOE) in 1985, called for monthly sampling of 14 of the 37 existing monitoring wells at the 300 Area plus the installation and sampling of 2 new wells. 27 refs., 25 figs., 15 tabs.

  17. Drying of water based foundry coatings: Innovative test, process design and optimization methods

    DEFF Research Database (Denmark)

    Di Muoio, Giovanni Luca; Johansen, Bjørn Budolph

    of Denmark with the overall aim to optimize the drying process of water based foundry coatings. Drying of foundry coatings is a relatively new process in the foundry industry that followed the introduction of water as a solvent. In order to avoid moisture related quality problems and reach production...... on real industrial cases. These tools have been developed in order to simulate and optimize the drying process and reduce drying time and power consumption as well as production process design time and cost of expensive drying equipment. Results show that test methods from other industries can be used...... Director Bjørn Budolph Johansen has been the company supervisor from March 2012 to June 2014. In this Industrial PhD Thesis we present the main results of several tests and simulations carried out from 2011 to 2014 at Global Castings A/S (former Vestas Wind Systems A/S) and at the Technical University...

  18. Ultraviolet photoelectron spectroscopy and electron stimulated desorption from CaF sub 2

    CERN Document Server

    Huisinga, M

    1999-01-01

    resulted in a positively charged sample surface, thus giving an undetermined electrostatic contribution to the F+ desorption energies. In this thesis, a method was developed allowing for the first time to measure a positive surface potential of an insulator under electron irradiation. Thus, the kinetic energy of F+ ions desorbing from CaF sub 2 crystals could be corrected for surface charge to determine the energy characteristic for the desorption process. The corrected peak of the F+ kinetic energy distribution was at about 0.9 eV for crystals cleaved in UHV. It was shown that coverage of the surface with oxygen or fluorine results in a high positive potential, while metallization causes a low surface potential. In particular, the surface potential of crystals cleaved in UHV shows a pronounced minimum after about 10 to 20 min of electron irradiation. This effect could be explained by a balance of F sup + desorption and diffusion of fluorine from the bulk. Calcium difluoride crystals were investigated with ul...

  19. Changes of structural and hydrogen desorption properties of MgH2 indused by ion irradiation

    Directory of Open Access Journals (Sweden)

    Kurko Sandra V.

    2010-01-01

    Full Text Available Changes in structural and hydrogen desorption properties of MgH2 induced by ion irradiation have been investigated. MgH2 powder samples have been irradiated with 45 keV B3+ and 120 keV Ar8+ions, with ion fluence of 1015 ions/cm2. The effects of ion irradiation are estimated by numerical calculations using SRIM package. The induced material modifications and their consequences on hydrogen dynamics in the system are investigated by XRD, particle size distribution and TPD techniques. Changes of TPD spectra with irradiation conditions suggest that there are several mechanisms involved in desorption process which depend on defect concentration and their interaction and ordering. The results confirmed that the near-surface area of MgH2 and formation of a substoichiometric MgHx (x<2 play a crucial role in hydrogen kinetics and that various concentrations of induced defects substantially influence H diffusion and desorption kinetics in MgH2. The results also confirm that there is possibility to control the thermodynamic parameters by controlling vacancies concentration in the system.

  20. Adsorption and desorption characteristics of adlay bran free phenolics on macroporous resins.

    Science.gov (United States)

    Yang, Qingyun; Zhao, Mouming; Lin, Lianzhu

    2016-03-01

    In this study, the adsorption and desorption characteristics of six macroporous resins including XAD-7HP, XAD-16, HP-20, HP-2MGL, SP-207 and SP-825 for enrichment of adlay bran free phenolics were studied. XAD-16, SP-207 and SP-825 were chosen for further study due to their strong adsorption and desorption capacities. XAD-16, SP-207 and SP-825 had similar phenolics adsorption/desorption behaviors. Pseudo-second-order kinetics model and Freundlich isotherm model were suitable for describing the whole exothermic and physical adsorption processes of adlay bran free phenolics on XAD-16, SP-207 and SP-825. After treatment with gradient elution on XAD-16 resin column, the free phenolics were mostly enriched (from 89.61 to 1015.26mg/100g) in 50% ethanol fraction. The oxygen radical absorbance capacity of 50% ethanol fraction was eight times higher than that of the crude extract. Therefore, the production of highly concentrated phenolics might expand the application of adlay bran used as a bioactive ingredient in functional food. Copyright © 2015 Elsevier Ltd. All rights reserved.