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Sample records for radionuclide adsorption characteristics

  1. Radionuclide adsorption characteristics around coastal water

    Energy Technology Data Exchange (ETDEWEB)

    Song, Young Il; Chung, Yang Geun; Hong, Sung Yul; Lee, Gab Bock [KEPCO, Taejon (Korea, Republic of)

    1999-07-01

    The adsorption capacity of radionuclides onto suspended sediment was experimented on each of the coastal seawater sampled around the Kori and the Wolsung nuclear power plant. During the experiment the quantity and size fraction of suspended sediment were adjusted and the seawater and sediment chemistry is approximated to the expected field condition. Because the sorption capacity depends on the specific minerals, ocean chemistry and radionuclide involved, it is necessary to analyze sediment mineralogy. Clay mineral is dominant in seabed mineral and suspended sediment as the result of x-ray diffraction. Radionuclide sorbed to silty-clay mineral can be rather transported to ocean than scavenged to seabed because of low quantity and fine grained suspended sediment in the coast around the Kori and the Wolsung. The result of adsorption examinations shows that {sup 139}Ce and {sup 51}Cr and {sup 110m}Ag are strongly sorbed to suspended particle, while {sup 137}Cs is less sorbed and {sup 60}Co uptake is varied with experiment condition, which can be inferred from various biological factors. (author). 9 refs., 2 tabs., 7 figs.

  2. 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.

  3. [Adsorption characteristics of ciprofloxacin in ustic cambosols].

    Science.gov (United States)

    Cui, Hao; Wang, Shu-ping

    2012-08-01

    In order to understand the adsorption characteristics of ciprofloxacin in ustic cambosols, static adsorption experiments were used to investigate dynamic and isothermal adsorption characteristics of ciprofloxacin in ustic cambosols, influence of pH on the adsorption process. Results showed that the absorption process of ciprofloxacin can be divided into two stages: fast adsorption and slow balance. The adsorption processes followed the pseudo-second-order kinetics, with adsorption rate of 1.138 x 10(-3) - 2.849 x 10(-2) kg x (min x mg)(-1). Adsorption isotherms of ciprofloxacin in ustic cambosols were well described by the Freundlich and Langmuir equation, Freundlich equation is more applicable than Langmuir equation, with the adsorption capacity (lgKf) of 2.725. Moreover, at the tested pH interval of 4-9, lgKd values of ciprofloxacin increased and then decreased with the increase of pH in ustic cambosols; the maximum adsorption of ciprofloxacin in ustic cambosols can be obtained when the pH value was 5 with lgKd value was 3.11; strong acid or alkali conditions were unfavorable to ciprofloxacin adsorption. It could be deduced that cationic adsorptions was one of the significant sorption mechanisms for ciprofloxacin in ustic cambosols.

  4. Removal of radionuclides from partitioning waste solutions by adsorption and catalytic oxidation methods

    Energy Technology Data Exchange (ETDEWEB)

    Yamagishi, Isao; Yamaguchi, Isoo [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Kubota, Masumitsu [Research Organization for Information Science and Technology (RIST), Tokai, Ibaraki (Japan)

    2000-09-01

    Adsorption of radionuclides with inorganic ion exchangers and catalytic oxidation of a complexant were studied for the decontamination of waste solutions generated in past partitioning tests with high-level liquid waste. Granulated ferrocyanide and titanic acid were used for adsorption of Cs and Sr, respectively, from an alkaline solution resulting from direct neutralization of an acidic waste solution. Both Na and Ba inhibited adsorption of Sr but Na did not that of Cs. These exchangers adsorbed Cs and Sr at low concentration with distribution coefficients of more than 10{sup 4}ml/g from 2M Na solution of pH11. Overall decontamination factors (DFs) of Cs and total {beta} nuclides exceeded 10{sup 5} and 10{sup 3}, respectively, at the neutralization-adsorption step of actual waste solutions free from a complexant. The DF of total {alpha} nuclides was less than 10{sup 3} for a waste solution containing diethylenetriaminepentaacetic acid (DTPA). DTPA was rapidly oxidized by nitric acid in the presence of a platinum catalyst, and radionuclides were removed as precipitates by neutralization of the resultant solution. The DF of {alpha} nuclides increased to 8x10{sup 4} by addition of the oxidation step. The DFs of Sb and Co were quite low through the adsorption step. A synthesized Ti-base exchanger (PTC) could remove Sb with the DF of more than 4x10{sup 3}. (author)

  5. An environmentally friendly process; Adsorption of radionuclide Tl-201 on fibrous waste tea

    Energy Technology Data Exchange (ETDEWEB)

    Eroglu, Hayrettin [Atatuerk Universitesi, Arastirma Hastanesi, Nuekleer Tip Ana Bilim Dali, 25240 Erzurum (Turkey); Yapici, Sinan [Atatuerk Universitesi, Muehendislik Fakueltesi, Kimya Muehendisligi Boeluemue, 25240 Erzurum (Turkey)], E-mail: syapici@atauni.edu.tr; Nuhoglu, Cigdem [Atatuerk Universitesi, Fen-Edebiyat Fakueltesi, Fizik Boeluemue, 25240 Erzurum (Turkey); Varoglu, Erhan [Atatuerk Universitesi, Arastirma Hastanesi, Nuekleer Tip Ana Bilim Dali, 25240 Erzurum (Turkey)

    2009-04-30

    This work presents an investigation of the adsorption of the radionuclide of Tl-201 from waste water on the fibrous tea factory waste. The experimental parameters were chosen as temperature, pH, stirring speed, adsorbent dose and nominal particle size in the ranges of 10.0-40.0 deg. C, 2.0-10.0, 300-720 rpm, 1.0-15.0 g/L and 0.15-0.71 mm, respectively. The most effective parameter on the adsorption yield was found to be pH of the solution. Fourier transforms infrared and electron paramagnetic resonance spectroscopy studies were performed for the characterisation of the adsorption on tea waste. The experimental data were found to be in good agreement with the isotherm models of Freundlich, Halsey, Handerson and Dubinin-Radushkevich. Thermodynamic analysis showed that the values of {delta}G and {delta}H are negative. It was obtained that the adsorption rate can be represented very well by second-order pseudo homogeneous kinetic model. All the results proved that fibrous tea plant waste makes an excellent adsorbent for Tl-201 radionuclide.

  6. Radionuclide-Chelating Agent Complexes in Low-Level Radioactive Decontamination Waste; Stability, Adsorption and Transport Potential

    Energy Technology Data Exchange (ETDEWEB)

    Serne, R. Jeffrey; Cantrell, Cantrell J.; Lindenmeier, Clark W.; Owen, Antionette T.; Kutnyakov, Igor V.; Orr, Robert D.; Felmy, Andrew R.

    2002-02-01

    Speciation calculations were done to determine whether organic complexants facilitate transport of radionuclides leached from waste buried in soils. EDTA readily mobilizes divalent transition metals and moderately impacts trivalent actinides. Picolinate readily mobilizes only Ni2+ and Co2+. These speciation predictions ignore the influence of soil adsorption and biodegradation that break apart the complexes. In adsorption studies, picolinate concentrations have to be >10-4 M to lower the adsorption of Ni and Co. For Sm(III), Th(IV), Np(V), U(VI), and Pu, the picolinate concentration must be >10-3 M before adsorption decreases. EDTA forms strong complexes with divalent transition metals and can stop adsorption of Ni and Co when EDTA solution concentrations are 10-5 M. EDTA complexes with Np(V), U(VI), and Pu are much weaker; EDTA concentrations would have to be >10-3 M to adversely effects non-transition metal/radionuclide adsorption. Most picolinate and ETDA-metal complexes appear to readily dissociate during interactions with soils. The enhanced migration of radionuclide-organic complexes may be limited to a few unique conditions. We recommend that mixtures of metal/radionuclides and EDTA should not be solidified or co-disposed with high pH materials such as cement. For weaker binding organic complexants, such as picolinate, citrate and oxalate, co-disposal of decontamination wastes and concrete should be acceptable.

  7. Adsorption Characteristics of Remazol Black B on Anoxic Sludge

    Institute of Scientific and Technical Information of China (English)

    HUANG Man-hong; CHEN Liang; CHEN Dong-hui; CHEN Chao-peng

    2009-01-01

    The adsorption characteristics of Remazol Black B on anoxic sludge were investigated. The parameters, such as initial pH, sulphate concentration, and temperature,affecting the dye adsorption were studied. The adsorption data were analyzed with three adsorption isotherm models,namely Langmuir, Freudlich, and linear partition. The results showed that adsorption of Remazol Black B on the sterilized sludge reached equilibrium in 4 h. It also indicated that pH had significant effect on anoxic sludge adsorption behavior. The adsorption capacity of anoxic sludge decreased with the increase of pH value and the maximum adsorption capacity of dyes occurred at pH = 3. The adsorptive capacities increased with the decrease of temperature and increase of sulphate concentration. Results also indicated that the adsorption equilibrium of Remazol Black B on anoxic sludge could be well fitted by Freundlich model.

  8. Cerium(III) molybdate nanoparticles: Synthesis, characterization and radionuclides adsorption studies

    Energy Technology Data Exchange (ETDEWEB)

    Yousefi, Taher, E-mail: Taher_yosefy@yahoo.com [NFCRS, Nuclear Science and Technology Institute, Kargher Ave, Tehran (Iran, Islamic Republic of); Tarbiat Moallem University, Mofatteh Ave, Tehran (Iran, Islamic Republic of); Khanchi, Ali Reza; Ahmadi, Seyed Javad [NFCRS, Nuclear Science and Technology Institute, Kargher Ave, Tehran (Iran, Islamic Republic of); Rofouei, Mohamad Kazem [Tarbiat Moallem University, Mofatteh Ave, Tehran (Iran, Islamic Republic of); Yavari, Ramin; Davarkhah, Reza; Myanji, Behzad [NFCRS, Nuclear Science and Technology Institute, Kargher Ave, Tehran (Iran, Islamic Republic of)

    2012-05-15

    Highlights: Black-Right-Pointing-Pointer A new inorganic nanoparticles with average size about 40 nm were synthesized by chemical method. Black-Right-Pointing-Pointer The morphology studies reveal existing nanowires among dense nanoparticles. Black-Right-Pointing-Pointer Investigation shows it has high stability in rough media and high affinity for Cs(I), U(VI), and Th(IV). Black-Right-Pointing-Pointer It was used for adsorption of radionuclides and removal of {sup 134}Cs from real sample. Black-Right-Pointing-Pointer These findings are important for evaluating human and environmental risk assessment. - Abstract: Cerium(III) molybdate nanostructure with average size about 40 nm was prepared by adding cerium(III) chloride and ammonium molybdate solutions under varying conditions. The product was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR), thermogravimetric analysis (TGA) and Brunauere Emmette Teller (BET) techniques. Ion exchange capacity of the sample for potassium ion and distribution coefficients (K{sub d}) for 23 metal ions were determined, the K{sub d} values for Tl(I), Pb(II), Th(IV), U(VI), and Cs(I) ions were found to be sufficiently high for their removal from various effluents. The adsorption behavior of the sample towards Cs(I){sub 134} species were studied. Finally, the binary separation of Dy(III)-U(VI), Sm(III)-Th(IV) and Cs(I)-Rb(I) and removal of Cs(I){sub 134} from the real sample were successfully achieved.

  9. Removal of Radionuclides from Waste Water at Fukushima Daiichi Nuclear Power Plant: Desalination and Adsorption Methods - 13126

    Energy Technology Data Exchange (ETDEWEB)

    Kani, Yuko; Kamosida, Mamoru; Watanabe, Daisuke [Hitachi Research Laboratory, Hitachi, Ltd., 7-2-1 Omika-cho, Hitachi, Ibaraki, 319-1221 (Japan); Asano, Takashi; Tamata, Shin [Hitachi Works, Hitachi-GE Nuclear Energy, Ltd. (Japan)

    2013-07-01

    Waste water containing high levels of radionuclides due to the Fukushima Daiichi Nuclear Power Plant accident, has been treated by the adsorption removal and reverse-osmosis (RO) desalination to allow water re-use for cooling the reactors. Radionuclides in the waste water are collected in the adsorbent medium and the RO concentrate (RO brine) in the water treatment system currently operated at the Fukushima Daiichi site. In this paper, we have studied the behavior of radionuclides in the presently applied RO desalination system and the removal of radionuclides in possible additional adsorption systems for the Fukushima Daiichi waste water treatment. Regarding the RO desalination system, decontamination factors (DFs) of the elements present in the waste water were obtained by lab-scale testing using an RO unit and simulated waste water with non-radioactive elements. The results of the lab-scale testing using representative elements showed that the DF for each element depended on its hydrated ionic radius: the larger the hydrated ionic radius of the element, the higher its DF is. Thus, the DF of each element in the waste water could be estimated based on its hydrated ionic radius. For the adsorption system to remove radionuclides more effectively, we studied adsorption behavior of typical elements, such as radioactive cesium and strontium, by various kinds of adsorbents using batch and column testing. We used batch testing to measure distribution coefficients (K{sub d}s) for cesium and strontium onto adsorbents under different brine concentrations that simulated waste water conditions at the Fukushima Daiichi site. For cesium adsorbents, K{sub d}s with different dependency on the brine concentration were observed based on the mechanism of cesium adsorption. As for strontium, K{sub d}s decreased as the brine concentration increased for any adsorbents which adsorbed strontium by intercalation and by ion exchange. The adsorbent titanium oxide had higher K{sub d}s and it

  10. Laboratory column experiments for radionuclide adsorption studies of the Culebra dolomite member of the Rustler Formation

    Energy Technology Data Exchange (ETDEWEB)

    Lucero, D.A.; Heath, C.E. [Sandia National Labs., Albuquerque, NM (United States); Brown, G.O. [Oklahoma State Univ., Stillwater, OK (United States). Biosystems and Agricultural Engineering Dept.

    1998-04-01

    Radionuclide transport experiments were carried out using intact cores obtained from the Culebra member of the Rustler Formation inside the Waste Isolation Pilot Plant, Air Intake Shaft. Twenty-seven separate tests are reported here and include experiments with {sup 3}H, {sup 22}Na, {sup 241}Am, {sup 239}Np, {sup 228}Th, {sup 232}U and {sup 241}Pu, and two brine types, AIS and ERDA 6. The {sup 3}H was bound as water and provides a measure of advection, dispersion, and water self-diffusion. The other tracers were injected as dissolved ions at concentrations below solubility limits, except for americium. The objective of the intact rock column flow experiments is to demonstrate and quantify transport retardation coefficients, (R) for the actinides Pu, Am, U, Th and Np, in intact core samples of the Culebra Dolomite. The measured R values are used to estimate partition coefficients, (kd) for the solute species. Those kd values may be compared to values obtained from empirical and mechanistic adsorption batch experiments, to provide predictions of actinide retardation in the Culebra. Three parameters that may influence actinide R values were varied in the experiments; core, brine and flow rate. Testing five separate core samples from four different core borings provided an indication of sample variability. While most testing was performed with Culebra brine, limited tests were carried out with a Salado brine to evaluate the effect of intrusion of those lower waters. Varying flow rate provided an indication of rate dependent solute interactions such as sorption kinetics.

  11. In vitro study of the adsorption characteristics of drugs.

    Science.gov (United States)

    Toyoguchi, Teiko; Ebihara, Mitsutaka; Ojima, Fumiyoshi; Hosoya, Jun; Nakagawa, Yoshito

    2005-05-01

    The adsorption characteristics of eight adsorbents, cholestyramine, colestimide, aluminum silicate, sucralfate, aluminum hydroxide, calcium polystyrene sulfonate, carbon sphere and medicinal carbon, on the drugs such as methotrexate, antidepressants, mizoribine and ciprofloxacin hydrochloride were investigated in vitro. Medicinal carbon showed an excellent adsorption of all the tested drugs while the carbon spheres showed a high but slow adsorption characteristic. Cholestyramine and colestimide showed a higher adsorption in methotrexate than the other adsorbents. Aluminum silicate and calcium polystyrene sulfonate showed higher adsorption in four antidepressants, clomipramine hydrochloride, imipramine hydrochloride, mianserin hydrochloride and trazodone hydrochloride. In mizoribine, there were no adsorbents that showed higher adsorption except for the medicinal carbon. In ciprofloxacin hydrochloride, aluminum preparations and calcium polystyrene sulfonate showed higher adsorption characteristics. It is suggested that several adsorbents are potentially useful treatments for drug overdoses, but that these adsorbents have the possibility of decreasing the effects of the co-administered medicines.

  12. Micellization and adsorption characteristics of CHAPS

    NARCIS (Netherlands)

    Giacomelli, CE; Vermeer, AWP; Norde, W

    2000-01-01

    The adsorption of CHAPS on hydrophobic latex particles was studied at 22 and 36 degrees C by determining the adsorbed amount and the enthalpy of adsorption. The adsorption process was compared to the micellization of the surfactant. Therefore, the critical micelle concentration (cmc) and the heat of

  13. Micellization and adsorption characteristics of CHAPS

    NARCIS (Netherlands)

    Giacomelli, CE; Vermeer, AWP; Norde, W

    2000-01-01

    The adsorption of CHAPS on hydrophobic latex particles was studied at 22 and 36 degrees C by determining the adsorbed amount and the enthalpy of adsorption. The adsorption process was compared to the micellization of the surfactant. Therefore, the critical micelle concentration (cmc) and the heat of

  14. Micellization and adsorption characteristics of CHAPS

    NARCIS (Netherlands)

    Giacomelli, C.E.; Norde, W.

    2000-01-01

    The adsorption of CHAPS on hydrophobic latex particles was studied at 22 and 36 C by determining the adsorbed amount and the enthalpy of adsorption. The adsorption process was compared to the micellization of the surfactant. Therefore, the critical micelle concentration (cmc) and the heat of micelli

  15. Characterization of ^{239,240}Pu Radionuclide Adsorption to Soil Particles and Mineral Dust Aerosols

    Science.gov (United States)

    Tatro, D. P.; Arimoto, R.; McMillan, N. J.; Barnes, M.

    2006-12-01

    The release of ^{239,240}Pu into the environment by nuclear weapons testing 50 years ago initiated the cyclic mobilization of Pu-contaminated soil particles via the resuspension of dust resulting in a widespread distribution of Pu and other radionuclides. It is unclear what enables the aeolian transport of Pu in the environment; plausible hypotheses of Pu binding to dust and soil particles include Pu adsorption to iron oxides/hydroxides, organic acids, or silicate minerals such as clays. To investigate the connections between surface soils, dust and radionuclides, samples of soil and/or dust were collected from the Project Gnome Site in Eddy County, NM, the Jemez Mountains near Los Alamos, NM, and two 50-year old attics and wind-blown dust in Big Spring, TX. This study tests the hypothesis that Pu is adsorbed onto Fe oxides and hydroxides that coat dust/soil particles. The samples are generally low in organic carbon (0.2 - 4.8%, except for the unburned Los Alamos sample at 9.4%), as measured by LOI (Loss On Ignition) at 360 °C. The citrate-bicarbonate-dithionite method (CDB) of Fe oxide removal, first proposed by Mehra and Jackson in 1960, was used to selectively extract Fe oxides from the samples while leaving silicate Fe intact. Chemical digestion of each sample creates two fractions, the extracted supernatant and a solid pellet residue. If the Pu were associated with Fe oxides, then Fe and Pu should both be selectively removed from the bulk sample during the CBD process, leaving the pellet depleted in Fe and Pu and the supernatant enriched. For Fe, this was confirmed by scanning electron microscope and petrographic analyses. Preliminary radiochemical analyses of Pu activity also verify this hypothesis. Pu activity is significantly lower in pellets than bulk samples (Pu activitypellet/Pu activitybulk average = 0.07, range 0.02-0.12); Pu activity in supernatants is significantly higher than in bulk samples (Pu activitysupernatant/Pu activitybulk average = 4

  16. [Adsorption dynamics and breakthrough characteristics based on the fluidization condition].

    Science.gov (United States)

    Wang, Jun; Wang, Yao; Huang, Xing; Yuan, Yi-Long; Chen, Rui-Hui; Zhou, Hang; Zhou, Dan-Dan

    2014-02-01

    Few studies on the adsorption dynamics and breakthrough characteristics based on the fluidization condition have been reported. In a fluidized bed adsorption reactor with phenol as the adsorbate and granular activated carbon as the adsorbent, the adsorption efficiency, adsorption dynamic characteristics, adsorption breakthrough curves and adsorption capacities were studied and compared with those of a fixed bed operated under the same conditions. The results showed that the adsorption efficiencies exceeded 93% in 5 min in both the fluidized conditions and fixed conditions at the superficial velocities of 8 mm x s(-1) and 13 mm x s(-1). Meanwhile, the above adsorption reactions fitted to Pseudo-second-order with linear correlation coefficients greater than 0.999. The adsorption capacity of fluidized conditions was 8.77 mg x g(-1) and 24.70 mg x g(-1) at the superficial velocities of 6 mm x s(-1) and 8 mm x s(-1). Generally, the fluidized bed reactor showed a higher adsorption efficiency and greater adsorption capacity than the fixed bed reactor.

  17. Adsorption characteristics of siloxanes in landfill gas by the adsorption equilibrium test

    Energy Technology Data Exchange (ETDEWEB)

    Nam, Sangchul; Namkoong, Wan [Department of Environmental Engineering, Konkuk University, Hwayang-Dong, Gwangjin-Gu, Seoul 143-701 (Korea, Republic of); Kang, Jeong-Hee; Park, Jin-Kyu [Department of Environmental Engineering, Anyang University, Anyang 5-Dong, Manan-Gu, Anyang-Si, Gyeonggi-Do 430-714 (Korea, Republic of); Lee, Namhoon, E-mail: nhlee@anyang.ac.kr [Department of Environmental Engineering, Anyang University, Anyang 5-Dong, Manan-Gu, Anyang-Si, Gyeonggi-Do 430-714 (Korea, Republic of)

    2013-10-15

    Highlights: • Equilibrium test was attempted to evaluate adsorption characteristics of siloxane. • L2 had higher removal efficiency in carbon compared to noncarbon adsorbents. • Total adsorption capacity of siloxane was 300 mg/g by coal activated carbon. • Adsorption characteristics rely on size of siloxane molecule and adsorbent pore. • Conversion of siloxane was caused by adsorption of noncarbon adsorbents. - Abstract: Due to the increase in energy cost by constantly high oil prices and the obligation to reduce greenhouse effect gases, landfill gas is frequently used as an alternative energy source for producing heat and electricity. Most of landfill gas utility facilities, however, are experiencing problems controlling siloxanes from landfill gas as their catalytic oxidizers are becoming fouled by silicon dioxide dust. To evaluate adsorption characteristics of siloxanes, an adsorption equilibrium test was conducted and parameters in the Freundlich and Langmuir isotherms were analyzed. Coconut activated carbon (CA1), coal activated carbon (CA2), impregnated activated carbon (CA3), silicagel (NCA1), and activated alumina (NCA2) were used for the adsorption of the mixed siloxane which contained hexamethyldisiloxane (L2), octamethylcyclotetrasiloxane (D4), and decamethylcyclopentasiloxane (D5). L2 had higher removal efficiency in noncarbon adsorbents compared to carbon adsorbents. The application of Langmuir and Freundlich adsorption isotherm demonstrated that coconut based CA1 and CA3 provided higher adsorption capacity on L2. And CA2 and NCA1 provided higher adsorption capacity on D4 and D5. Based on the experimental results, L2, D4, and D5 were converted by adsorption and desorption in noncarbon adsorbents. Adsorption affinity of siloxane is considered to be affect by the pore size distribution of the adsorbents and by the molecular size of each siloxane.

  18. Phosphorus isothermal adsorption characteristics of mulch of bioretention

    OpenAIRE

    Mei Ying; Yang Xiao-Hua; Jiang Rong; Di Chong-Li; Zhang Xue-Jun

    2012-01-01

    This study aims to identify mulch of bioretention which has high phosphorus sorption capacity. The phosphorus adsorption characteristics of five types of mulch of bioretention are studied by three isothermal adsorption experiments. Results show that the Langmuir eqution is suitable for describing absorption characteristics of five types of mulch. The positive values of Gibbs free energy for phosphorus indicate that the phosphorus biosorption by five mulches is a non-spontaneous process,...

  19. Adsorption characteristics of activated carbon hollow fibers

    OpenAIRE

    2009-01-01

    Carbon hollow fibers were prepared with regenerated cellulose or polysulfone hollow fibers by chemical activation using sodium phosphate dibasic followed by the carbonization process. The activation process increases the adsorption properties of fibers which is more prominent for active carbone fibers obtained from the cellulose precursor. Chemical activation with sodium phosphate dibasic produces an active carbon material with both mesopores and micropores.

  20. Adsorption characteristics of water vapor on ferroaluminophosphate for desalination cycle

    KAUST Repository

    Kim, Youngdeuk

    2014-07-01

    The adsorption characteristics of microporous ferroaluminophosphate adsorbent (FAM-Z01, Mitsubishi Plastics) are evaluated for possible application in adsorption desalination and cooling (AD) cycles. A particular interest is its water vapor uptake behavior at assorted adsorption temperatures and pressures whilst comparing them to the commercial silica gels of AD plants. The surface characteristics are first carried out using N2 gas adsorption followed by the water vapor uptake analysis for temperature ranging from 20°C to 80°C. We propose a hybrid isotherm model, composing of the Henry and the Sips isotherms, which can be integrated to satisfactorily fit the experimental data of water adsorption on the FAM-Z01. The hybrid model is selected to fit the unusual isotherm shapes, that is, a low adsorption in the initial section and followed by a rapid vapor uptake leading to a likely micropore volume filling by hydrogen bonding and cooperative interaction in micropores. It is shown that the equilibrium adsorption capacity of FAM-Z01 can be up to 5 folds higher than that of conventional silica gels. Owing to the quantum increase in the adsorbate uptake, the FAM-Z01 has the potential to significantly reduce the footprint of an existing AD plant for the same output capacity. © 2014 Elsevier B.V.

  1. Adsorption-Desorption Characteristics of Chlorimuron-Ethyl in Soils

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The adsorption-desorption characteristics of chlorimuron-ethyl in soils were investigated to provide the basic data for evaluating the safety in field and the risk to water resource. The adsorption-desorption experiment was conducted by the batch equilibration and HPLC techniques; furthermore, data were analyzed with 5 mathematic models to describe the characteristics and mechanism of adsorption-desorption and translocation of the herbicide in soils. The results showed that the adsorption-desorption isotherms of chlorimuron-ethyl fitted for the Freundlich model well, and the physical reaction presents the main contribution during the adsorption-desorption process. The adsorption values (Kads-f) of chlorimuron-ethyl in 8 types of soil ranged from 0.798 to 6.891. The isotherms of 2# (Jiangxi clay) and 3# (Jiangxi sand loam)soils belong to the S-type curve, while the isotherms of another 6 type soils belong to the L-type isotherm. The results of desorption indicated that the hysteresis phenomena appeared during the desorption process, and the hysteresis coefficients(H) of the herbicides in 8 soils varied from 0.259-0.980. Furthermore, Kads-f and desorption values (Kdes-f) increased with the OM (%) and the clay content increasing, while the values decreased with the soils pH increasing. The H values decreased with the OM and the clay content increasing, and increased with the soils pH increasing. It can be concluded that the low adsorption abilities of chlorimuron-ethyl in test soils and un-reversible adsorption existed in the process, which will induce the great translocation of the herbicide after application in field. It can be transported to ground or groundwater causing risk to environments. The physical and chemical properties of soils, including the OM, the clay content, and the pH of soil were the dominating factors during the adsorption-desorption.

  2. Phosphorus isothermal adsorption characteristics of mulch of bioretention

    Directory of Open Access Journals (Sweden)

    Mei Ying

    2012-01-01

    Full Text Available This study aims to identify mulch of bioretention which has high phosphorus sorption capacity. The phosphorus adsorption characteristics of five types of mulch of bioretention are studied by three isothermal adsorption experiments. Results show that the Langmuir eqution is suitable for describing absorption characteristics of five types of mulch. The positive values of Gibbs free energy for phosphorus indicate that the phosphorus biosorption by five mulches is a non-spontaneous process, and the values of mean sorption free energy of mulch are less than 8 kJ/mol, which proves that the adsorption process can be dominated by physical forces. The vermiculite is the better mulch of bioretention based on high phosphorus removal capacity.

  3. Correlation between coal characteristics and methane adsorption on China's coals

    Institute of Scientific and Technical Information of China (English)

    YU Hong-guan; YUAN Jian; SONG Ji-yong; LENG Shu-wei

    2007-01-01

    It is highly important to investigate relationship between coal characteristics and methane adsorption on coal in the fields of coalbed methane recovery. Based on data examination of coal quality indexes collected from the literatures, regression equations for Langmuir adsorption constants, VL or VL/PL, and coal quality indexes for selected coal samples were developed with multiple linear regression of SPSS software according to the degree of coal metamorphosis. The regression equations built were tested with data collected from some literatures, and the influences of coal quality indexes on CH4 adsorption on coals were studied with investigation of regression equations, and the reasons of low accuracy to Langmuir constants calculated with regression equation for a few coal samples were investigated. The results show that the regression equations can be employed to predict Langmuir constants for methane adsorption isotherms on coals obtained using volumetric gas adsorption experiments, which are conducted at 30 ℃ on a wet or dried coal samples with less than 30% ash content in coal. The influence of same coal quality index with various coal rank or influence of various coal quality indexes for same coal rank on CH4 adsorption is not consistent. The regression equations have different accuracy to different coal rank, in which the VL equations supply better prediction accuracy for anthracite and higher prediction error for lower metamorphosis coal, and the PL prediction error with VL and VL/PL equations is lower to bituminous coal and higher to anthracite.

  4. Adsorption and desorption characteristics of diphenylarsenicals in two contrasting soils

    Institute of Scientific and Technical Information of China (English)

    Anan Wang; Shixin Li; Ying Teng; Wuxin Liu; Longhua Wu; Haibo Zhang; Yujuan Huang

    2013-01-01

    Diphenylarsinic acid (DPAA) is formed during the leakage of aromatic arsenic chemical weapons in soils,is persistent in nature,and results in arsenic contamination in the field.The adsorption and desorption characteristics of DPAA were investigated in two typical Chinese soils,an Acrisol (a variable-charge soil) and a Phaeozem (a constant-charge soil).Their thermodynamics and some of the factors influencing them (i.e.,initial pH value,ionic strength and phosphate) were also evaluated using the batch method in order to understand the environmental fate of DPAA in soils.The results indicate that Acrisol had a stronger adsorption capacity for DPAA than Phaeozem.Soil DPAA adsorption was a spontaneous and endothermic process and the amount of DPAA adsorbed was affected significantly by variation in soil pH and phosphate.In contrast,soil organic matter and ionic strength had no significant effect on adsorption.This suggests that DPAA adsorption may be due to specific adsorption on soil mineral surfaces.Therefore,monitoring the fate of DPAA in soils is recommended in areas contaminated by leakage from chemical weapons.

  5. A Study of Adsorptive Characteristics of Australian Coals

    Science.gov (United States)

    Lan, Y. P.; Tsai, L. L.

    2012-04-01

    Ever since the Kyoto Protocol, controlling carbon dioxide emission and reducing its content in atmosphere are very important environmental issues up to today. One of the effective methods for permanent sequestration of anthropogenic CO2 is to inject CO2 into deep, unminable coal seams and recover coal bed methane at the same time. CO2-ECBM technology had been proved to be very promising to meet the needs of both environment and energy. Beside other external environment factors, capacity of CO2 adsorption and CH4 desorption are the most influencing factors in selection of sites for the geological storage of CO2. Therefore, the objective of this study is to understand the relationship between gas adsorption and CO2 sequestration, by various experiments for the characterization of Australian of coals. Generally speaking, coal seam gas comprises mostly of CH4, CO2, C2H6, and N2. However, some of the Australian coals were reported with significant amount of CO2 up to 90%, which might strongly affect their capacity of CO2 capture and storage (CCS). High to medium volatile bituminous coals from Sydney Basin and Bowen Basin, southeast Australia were selected in this study. Experiments include maceral composition and vitrinite reflectance measurements, petrographic analysis, Proximate analysis, Ultimate analysis, specific surface area analysis as well as CO2 and CH4 adsorption experiments were performed. Parameters for difference adsorption functions (Langmuir, BET, D-R and D-A) were then calculated to fit their adsorption isotherms the best fitting curve can then be found. Among these adsorption functions, Langmuir is the most basic and commonly used function theory. The results of all experiments were synthesized to discuss the relations among each other, so as to establish the relationship between gas adsorption and coal characteristics.

  6. Adsorption characteristics of methane on Maxsorb III by gravimetric method

    KAUST Repository

    Thu, Kyaw

    2014-11-01

    Adsorption characteristics of CH4 on the carbonaceous porous material is evaluated for possible application in adsorbed natural gas (ANG) system. Adsorption uptakes at assorted temperatures (25-80 °C) and pressures ranging from ambient to relatively high pressure i.e., 8.0 MPa are experimentally investigated. Surface characteristics such as pore surface area, micropore volume and pore size distribution of the adsorbent (Maxsorb III) are first evaluated using Classical Volumetric Method i.e., the manometric method with N2 gas adsorption at 77 K. The sorption measurements for methane, CH4 gas are carried out by thermogravimetric (TGA) method using magnetic suspension balance coupled with the automatic dosing system. The buoyancy measurements were first conducted using Helium gas as adsorbate. Buoyancy correction is applied to all sets of measured data and the specific uptake capacities (g/g of adsorbent) at various temperatures and pressures were calculated. The isotherm data were then fitted using Langmuir and Tòth isotherm models. It is observed that the data can be satisfactorily fitted using Tòth model with excellent fitting accuracy around 2.2% within the experimental range. The outcome of the present study especially the adsorption data at high pressures is applicable to accurate design and modeling of Adsorbed Natural Gas (ANG) systems. © 2014 Elsevier Ltd. All rights reserved.

  7. Surface pore tension and adsorption characteristics of polluted sediment

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Most natural sediment particles have numerous pores and a complex surface texture which facilitates their adsorption of contaminants. Particle surface structure,therefore,is an important instrumental factor in the transport of contaminants,especially in water environments. This paper reports on the results of adsorption-desorption experiments to analyze polluted sediment surface pore tension characteristics performed on samples from the bottom of Guanting Reservoir. In our analysis,the Frenkel-Halsey-Hill(FHH) equation is applied to calculate the fractal dimensions of particles to quantify the surface roughness and pore tension characteristics. The results show that the surface fractal dimensions of sediment particle surfaces normally measure from 2.6 to 2.85. The volume of pores smaller than 10 nm changes significantly after being contaminated with pollutants and the fractal dimension decreases because the pores adsorb the contaminants.

  8. Cerium(III) molybdate nanoparticles: Synthesis, characterization and radionuclides adsorption studies.

    Science.gov (United States)

    Yousefi, Taher; Khanchi, Ali Reza; Ahmadi, Seyed Javad; Rofouei, Mohamad Kazem; Yavari, Ramin; Davarkhah, Reza; Myanji, Behzad

    2012-05-15

    Cerium(III) molybdate nanostructure with average size about 40nm was prepared by adding cerium(III) chloride and ammonium molybdate solutions under varying conditions. The product was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR), thermogravimetric analysis (TGA) and Brunauere Emmette Teller (BET) techniques. Ion exchange capacity of the sample for potassium ion and distribution coefficients (K(d)) for 23 metal ions were determined, the K(d) values for Tl(I), Pb(II), Th(IV), U(VI), and Cs(I) ions were found to be sufficiently high for their removal from various effluents. The adsorption behavior of the sample towards Cs(I)(134) species were studied. Finally, the binary separation of Dy(III)-U(VI), Sm(III)-Th(IV) and Cs(I)-Rb(I) and removal of Cs(I)(134) from the real sample were successfully achieved.

  9. Scaling Dimensions of Nitrogen Adsorption Characteristics in Modulated Mesoporous Aluminophosphates

    Science.gov (United States)

    Petrakis; Pasxalidis; Theocharis; Hudson; Pomonis

    1997-01-01

    Mesoporous alumina-aluminophosphates (MAAP) of the general formula Al100PXM20 (M = Al, Fe, Cr, and Ni and X = 0, 4.5, 9, 18, 36, 72, and 144) were tested for their pore size distribution by nitrogen adsorption. The distribution of pore size can be modified by the addition of phosphorus. The scaling or fractal dimensions (DS) of the adsorption characteristics in the pores, calculated from the plots of the log of the corresponding cumulative BJH desorption pores surface area versus the log of the corresponding pore size, indicate that for low values of P/P0, the adsorption proceeds in a two-dimensional manner, independently of the pore size distribution (p.s.d.). However, at high P/P0 values and narrow p.s.d. DS >/= 3, while at wide p.s.d. DS > 3. At medium P/P0 values the DS values obtained were found as high as 10 for narrow pore size distribution and decrease as the p.s.d. becomes wide by the addition of phosphorus. These phenomena are related to the supercritical condensation of nitrogen in the pores of MAAP.

  10. Characteristics of rapeseed oil cake using nitrogen adsorption

    Science.gov (United States)

    Sokołowska, Z.; Bowanko, G.; Boguta, P.; Tys, J.; Skiba, K.

    2013-09-01

    Adsorption of nitrogen on the rapeseed oil cake and rapeseed oil cake with wheat meal extrudates was investigated. The results are presented as adsorption-desorption isotherms. The Brunauer-Emmet and Teller equation was used to analyse the experimental sorption data. To obtain estimates of the surface area and surface fractal dimension, the sorption isotherms were analyzed using the Brunauer-Emmet and Teller and Frenkel-Halsey-Hill equations. Mesopore analysis was carried out using the Dollimore and Heal method. The properties and surface characteristic of rapeseed oil cake extrudates are related to different basic properties of particular samples and duration of the extrusion process. Extrusion conditions lead to essential differences in particular products. For all kinds of rapeseed oil cakes the amount of adsorbed nitrogen was different, but for the rapeseed oil cake extrudates a large amount of adsorbed nitrogenwas observed. The average surface area of the rapeseed oil cake extrudates was about 6.5-7.0 m2 g-1, whereas it was equal to about 4.0-6.0 m2 g-1 for rapeseed oil cake with the wheat meal extrudates. In the case of non-extruded rapeseed oil cake and wheat meal, the dominant group included ca. 2 and 5 nmpores. The values of surface fractal dimension suggested that the surface of the extrudates was more homogenous than that of the raw material. Duration of the extrusion process to 80 s resulted in a decrease in the specific surface area, surface fractal dimension, and porosity of the extrudates.

  11. Use of radionuclides at small water purification plants and in industrial waste water treatment by radiation adsorption method

    Energy Technology Data Exchange (ETDEWEB)

    Brusentseva, S.A.; Egorov, G.F.; Shubin, V.N. [and others

    1993-12-31

    An irradiation technique for potable water treatment is described. Use of radionuclides as a source of radiation allows for the automation of the process. The treatment is considered to be effective in waste water treatment to remove phenols, pesticides, and other toxic compounds.

  12. Adsorption characteristics of brilliant green dye on kaolin.

    Science.gov (United States)

    Nandi, B K; Goswami, A; Purkait, M K

    2009-01-15

    Experimental investigations were carried out to adsorb toxic brilliant green dye from aqueous medium using kaolin as an adsorbent. Characterization of kaolin is done by measuring: (i) particle size distribution using particle size analyzer, (ii) BET surface area using BET surface analyzer, and (iii) structural analysis using X-ray diffractometer. The effects of initial dye concentration, contact time, kaolin dose, stirring speed, pH and temperature were studied for the adsorption of brilliant green in batch mode. Adsorption experiments indicate that the extent of adsorption is strongly dependent on pH of solution. Free energy of adsorption (DeltaG0), enthalpy (DeltaH0) and entropy (DeltaS0) changes are calculated to know the nature of adsorption. The calculated values of DeltaG0 at 299K and 323K indicate that the adsorption process is spontaneous. The estimated values of DeltaH0 and DeltaS0 both show the negative sign, which indicate that the adsorption process is exothermic and the dye molecules are organized on the kaolin surface in less randomly fashion than in solution. The adsorption kinetic has been described by first-order, pseudo-second-order and intra-particle-diffusion models. It was observed that the rate of dye adsorption follows pseudo-second-order model for the dye concentration range studied in the present case. Standard adsorption isotherms were used to fit the experimental equilibrium data. It was found that the adsorption of brilliant green on kaolin follows the Langmuir adsorption isotherm.

  13. [Adsorption characteristics of typical PPCPs onto river sediments and its influencing factors].

    Science.gov (United States)

    Wang, Kai; Li, Kan-Zhu; Zhou, Yi-Yuan; Liu, Zhen-Hong; Xue, Gang; Gao, Pin

    2015-03-01

    A batch equilibrium method was used to investigate the adsorption characteristics of ciprofloxacin (CIP), tetracycline (TC), sulfamethoxazole (SMX) and triclosan (TCS) onto Huangpu River sediments. Effects of adsorption time, initial concentration, solution pH and temperature on the adsorption process were studied. The results showed that the adsorption process of these PPCPs onto sediments was a two-step process: a rapid adsorption followed by a slow balance. The equilibrium time was about 4 h. The pH value had a significant effect on the adsorption of CIP, TC and TCS, whereas the effect on SMX adsorption was negligible. The kinetic results indicated that the adsorption processes followed the pseudo-second-order model, with adsorption rate in the range of 4.89 x 10(-3)-1.96 x 10(-2) kg x (min x mg)(-1). Adsorption isotherms were well described by the Freundlich and linear equations. As temperature increased, the amount of SMX and TC adsorbed increased, whereas CIP and TCS decreased. CIP, TC and TCS had a strong tendency to adsorb onto sediments, while the adsorption of SMX was unfavorable. When the initial concentration of PPCPs was 10 mg x L(-1), the equilibrium adsorption capacities of CIP, TC, SMX and TCS reached 702.8, 733.1, 54.7 and 695.0 mg x kg(-1), respectively.

  14. Characteristics of Phosphorous Adsorption and Desorption by Organo-Mineral Colloidal Complexes of Purple Paddy Soils

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The kinetic characteristics of P adsorption and desorption by organo-mineral colloidal complexes (OMC)were studied using acid, calcareous and neutral purple paddy soils taken from Chongqing and Sichuan, China.The results showed that the P adsorption capacity of the organo-mineral colloidal complexes differed with the soil types, being higher for the acid and calcareous purple soils than for the neutral purple soils. Partial removal of the organic matter increased the adsorption capacity of the colloidal complexes. A very significant positive correlation was found between the amounts of P desorbed from OMC and the P saturation degrees.The P adsorption reaction was quick at the early stage and slowed later. The raise of temperature increased P adsorption capacity and P adsorption rate of the colloidal complexes. The adsorption processes could be described by the Elovich equation.

  15. Adsorption Characteristics of Polyvinyl Alcohols in Solution on Expanded Graphite

    Directory of Open Access Journals (Sweden)

    Xiu-Yan Pang

    2012-01-01

    Full Text Available Expanded graphite (EG adsorbent was prepared with 50 mesh graphite as raw materials, potassium permanganate as oxidant, and vitriol as intercalation compound. Three kinds of polyvinyl alcohol (PVA with different degree of polymerization (DP in aqueous solution were used as adsorbates. We have studied the influence of initial PVA concentration, temperature and ionic strength on adsorption capacity. Langmuir constants and Gibbs free energy change (⊿G° were calculated according to experimental data respectively. Thermodynamic analysis indicates the equilibrium adsorbance of PVA on EG increase with the rise of SO42– concentration. Adsorption isotherms of PVA with different degree of polymerization are all types and we deduce PVA molecules lie flat on EG surface. Adsorption processes are all spontaneous. Kinetic studies show that the kinetic data can be described by pseudo second-order kinetic model. Second-order rate constants and the initial adsorption rate rise with the increasing of temperature and half-adsorption time decreases with the increasing of temperature. The adsorption activation energy of each PVA is less than 20 kJ•mol−1, physical adsorption is the major mode of the overall adsorption process.

  16. Adsorption Characteristics of H2 on Molecular Sieves 5A at 77 K

    Institute of Scientific and Technical Information of China (English)

    XIA; Ti-rui; YANG; Hong-guang; LIU; Wen-jun; LIU; Zhen-xing; ZHAO; Wei-wei; HAN; Zhi-bo

    2013-01-01

    With the aim of applying cryogenic molecular sieves bed(CMSB)to a tritium extraction system(TES)for ITER TBM,adsorption characteristics of H2 on a molecular sieve at 77 K was investigated by a volumetric method.The adsorption isotherms for H2 in a pressure range between about 1 and 103 Pa was shown in Fig.1,and alkaline treatment(CaA includes not only Na+but also Ca2+)improved the adsorption

  17. ADSORPTION CHARACTERISTICS OF SACFs FORA VARIETY OF DYES

    Institute of Scientific and Technical Information of China (English)

    ChenShuixia; LuYun; 等

    1998-01-01

    The isothermal adsorption of dyes on a variety of sisal based activated carbon fibers (SACFs),and the influence of pH and temperature on adsorption are discussed in this paper.The results indicate that the adsorption of methylene blue,crystal violet and Eriochrome blue black R on SACFs shows type I isotherms and can be described by the Langmuir equation or the Freudlich equation.The acidity of solution has greatly influence over the adsorption amounts of methylene blue,crystal violet and Eriochrome blue black R.As pHs of the solutions were adjusted to increase or decrease from the original acidity of the solution(4.7,4.1 and 4.0 for methylene blue,crystal violet and Eriochrome blue black R,respectively),the amounts of dyes adsorbed on SACFs increased.The adsorption temperature(in the range of 25-50℃) exerts little influence on the adsorption amount of methylene blue,crystal violet and fluorescein.For azo dyes (Eriochrome blue black R and Eriochrome black T),however,the adsorption amount increases slightly with the elevation of temperature.

  18. Adsorptive

    Directory of Open Access Journals (Sweden)

    Vinod Kumar Gupta

    2017-05-01

    Full Text Available This work explores the feasibility of natural fibers derived from Ficus carica plant as an alternative precursor for the preparation of activated carbon via microwave assisted H3PO4 activation. The properties of activated carbon were investigated by scanning electron microscope (SEM and Fourier transform spectroscopy (FTIR. The operational parameters, chemical impregnation ratio, microwave power and irradiation time on the carbon yield and adsorption capability were investigated. Adsorption performance of Cu(II and Ni(II onto activated carbon was investigated as a function of pH, contact time, initial metal ion concentration and temperature. The adsorption capacity of Cu(II and Ni(II onto the adsorbent was found to be 23.08 and 18.78 mg/g, respectively. Adsorption of metal ions followed second order kinetics with best fit for Fraundlich adsorption isotherm. The values of thermodynamic parameters such as enthalpy change (ΔH°, entropy change (ΔS° and free energy change (ΔG° were evaluated for the adsorption of both the metal ions. Adsorption of metal ions onto activated carbon was spontaneous and endothermic in nature. The results suggested that activated carbon developed from natural fibers successfully improved the metal ions adsorption capacity. On the basis of our findings, the adsorbent could be used as a detoxifying agent for better management of industrial effluents.

  19. [Characteristics of Adsorption Leaching and Influencing Factors of Dimethyl Phthalate in Purple Soil].

    Science.gov (United States)

    Wang, Qiang; Song, Jiao-yan; Zeng, Wei; Wang, Fa

    2016-02-15

    The typical soil-purple soil in Three Gorges Reservoir was the tested soil, the characteristics of adsorption leaching of dimethyl phthalate (DMP) in contaminated water by the soil, and the influencing factors in the process were conducted using soil column leaching experiment. The results showed that the parabolic equation was the best equation describing adsorption kinetics of DMP by soils. The concentration of DMP in the leaching solution had significant effect on the adsorption amounts of DMP. With the increasing concentration of DMP in the leaching solution, the adsorption capacities of DMP by purple soil increased linearly. The ionic strength and pH in leaching solution had significant effects on adsorption of DMP. On the whole, increasing of the ionic strength restrained the adsorption. The adsorption amounts at pH 5.0-7.0 were more than those under other pH condition. The addition of exogenous organic matter (OM) in purple soil increased the adsorption amount of DMP by purple soil. However, the adsorption amount was less than those with other addition amounts of exogenous OM when the addition of exogenous OM was too high (> or = 30 g x kg(-1)). The addition of surfactant sodium dodecylbenzene sulfonic acid (SDBS) in purple soil increased the adsorption amount of DMP by purple soil. The adsorption amount was maximal when the addition amount of SDBS was 50 mg x kg(-1). However, the adsorption amounts decreased with increasing addition amounts of SDBS although the adsorption amounts were still more than that of the control group, and the adsorption amount was almost equal to that of the control group when the addition amount of SDBS was 800 mg x kg(-1). Continuous leaching time affected the vertical distribution of DMP in the soil column. When the leaching time was shorter, the upper soil column adsorbed more DMP, while the DMP concentrations in upper and lower soil columns became similar with the extension of leaching time.

  20. ADSORPTION CHARACTERISTICS OF L-HISTIDINE ON ACTIVE CARBON

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Adsorption properties of L-histidine on active carbon were studied in the paper, which are affected by the main parameters, such as the quantity percent of active carbon, pH value of the solution, the time of adsorption equilibrium and adsorption temperature. The results indicate that adsorption equilibrium time of L-his on active carbon is about 80 minutes. With the increasing of the quantity percent of active carbon, the adsorbance of L-his decreases sharply, and increases lighter after that. When the quantity percent of active carbon is 10%, the adsorbance reaches the minimum.pH value of solution and extraction temperature have great affection on the adsorption. When the pH value is higher or lower than the pI of L-his, the adsorbance is small, even zero. It is proven that the experimental equilibrium data which are obtained under the conditions of 80 ℃and pH=1.0, are fitted with the Freundlich equation: q=2.5914c0.8097. The results can provide certain references in L-his adsorption process of industrial operation.

  1. Adsorption characteristics of Cu(II) and Pb(II) onto expanded perlite from aqueous solution.

    Science.gov (United States)

    Sari, Ahmet; Tuzen, Mustafa; Citak, Demirhan; Soylak, Mustafa

    2007-09-01

    The adsorption characteristics of Cu(II) and Pb(II) onto expanded perlite (EP) from aqueous solution were investigated with respect to the changes in pH of solution, adsorbent dosage, contact time and temperature of solution. For the adsorption of both metal ions, the Langmuir isotherm model fitted to equilibrium data better than the Freundlich isotherm model. Using the Langmuir model equation, the monolayer adsorption capacity of EP was found to be 8.62 and 13.39 mg/g for Cu(II) and Pb(II) ions, respectively. Dubinin-Radushkevich (D-R) isotherm model was also applied to the equilibrium data and the mean free energies of adsorption were found as 10.82 kJ/mol for Cu(II) and 9.12 kJ/mol for Pb(II) indicating that the adsorption of both metal ions onto EP was taken place by chemical ion-exchange. Thermodynamic functions, the change of free energy (DeltaG degrees ), enthalpy (DeltaH degrees ) and entropy (DeltaS degrees ) of adsorption were also calculated for each metal ions. These parameters showed that the adsorption of Cu(II) and Pb(II) ions onto EP was feasible, spontaneous and exothermic at 20-50 degrees C. Experimental data were also evaluated in terms of kinetic characteristics of adsorption and it was found that adsorption process for both metal ions followed well pseudo-second-order kinetics.

  2. Characteristics of simultaneous ammonium and phosphate adsorption from hydrolysis urine onto natural loess.

    Science.gov (United States)

    Jiang, Shanqing; Wang, Xiaochang; Yang, Shengjiong; Shi, Honglei

    2016-02-01

    Nutrient recovery from human urine is a promising pretreatment of domestic wastewater and provides a sustainable recyclability of N and P. In this study, batch experiments were conducted to identify the characteristics of natural loess (NL) for the adsorption and recovery of ammonium and phosphate from hydrolysis urine (HU). The adsorption mechanisms, the adsorption kinetics and isotherms, as well as the major influencing factors, such as pH and temperature, were investigated. Results revealed that adsorption of ammonium occurred by means of ion exchange and molecule adsorption with the ≡ Si-OH groups, while phosphate adsorption was based on the calcium phosphate precipitation reaction and formation of inner-sphere complexes with ≡ M-OH groups. The adsorption processes of ammonium and phosphate were well described by the pseudo-second-order kinetic model and the Freundlich isotherm model. Adsorption of phosphate was endothermic, while ammonium adsorption was exothermic. Furthermore, the maximum ammonium and phosphate adsorption capacities of NL was 23.24 mg N g(-1) and 4.01 mg P g(-1) at an initial pH of 9 and 10, respectively. Results demonstrated that nutrient-adsorbed NL used as compound fertilizer or conventional fertilizer superaddition was feasible for its high contents of N and P as well as its environmental friendliness.

  3. Atrazine adsorption removal with nylon6/polypyrrole core-shell nanofibers mat: possible mechanism and characteristics

    Science.gov (United States)

    Yang, Bi-Yi; Cao, Yang; Qi, Fei-Fei; Li, Xiao-Qing; Xu, Qian

    2015-05-01

    A functionalized nylon6/polypyrrole core-shell nanofibers mat (PA6/PPy NFM) was prepared via situ polymerization on nylon6 electrospun nanofibers mat (PA6 NFM) template and used as an adsorbent to remove atrazine from aqueous solutions. The core-shell structure of PA6/PPy NFM can be clearly proved under scanning electron microscope (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). The effects of initial solution pH and ionic strength, as well as the comparison of the adsorption capacity of functionalized (PA6/PPy NFM) and non-functionalized (PA6 NFM) adsorbent, were examined to reveal the possible adsorption mechanism. The results indicated that π-π interaction and electrostatic interaction should play a key role in the adsorption process. The kinetics and thermodynamics studies also further elucidated the detailed adsorption characteristics of atrazine removal by PA6/PPy NFM. The adsorption of atrazine could be well described by the pseudo-second-order equation. The adsorption equilibrium data was well fitted with the Freundlich isotherm model with a maximum adsorption capacity value of 14.8 mg/g. In addition, the increase of adsorption rate caused by a temperature increase could be felicitously explained by the endothermic reaction. The desorption results showed that the adsorption capacity remained almost unchanged after six adsorption/desorption cycles. These results suggest that PA6/PPy NFM could be employed as an efficient adsorbent for removing atrazine from contaminated water sources.

  4. The adsorption characteristics of osteopontin on hydroxyapatite and gold

    Energy Technology Data Exchange (ETDEWEB)

    Dolatshahi-Pirouz, A.; Kolman, N. [Interdisciplinary Nanoscience Center (iNANO), Aarhus University, 8000 Aarhus C (Denmark); Arpanaei, A. [Interdisciplinary Nanoscience Center (iNANO), Aarhus University, 8000 Aarhus C (Denmark); Department of Industrial and Environmental Biotechnology, National Institute of Genetic Engineering and Biotechnology, P.O. Box: 14965/161, Tehran (Iran, Islamic Republic of); Jensen, T. [Interdisciplinary Nanoscience Center (iNANO), Aarhus University, 8000 Aarhus C (Denmark); Orthopaedic Research Laboratory, Aarhus University Hospital, 8000 Aarhus C (Denmark); Foss, M., E-mail: foss@inano.au.dk [Interdisciplinary Nanoscience Center (iNANO), Aarhus University, 8000 Aarhus C (Denmark); Chevallier, J. [Department of Physics and Astronomy, Aarhus University, 8000 Aarhus C (Denmark); Kingshott, P. [Interdisciplinary Nanoscience Center (iNANO), Aarhus University, 8000 Aarhus C (Denmark); Baas, J.; Soballe, K. [Orthopaedic Research Laboratory, Aarhus University Hospital, 8000 Aarhus C (Denmark); Besenbacher, F. [Interdisciplinary Nanoscience Center (iNANO), Aarhus University, 8000 Aarhus C (Denmark); Department of Physics and Astronomy, Aarhus University, 8000 Aarhus C (Denmark)

    2011-04-08

    The adsorption of osteopontin on hydroxyapatite (HA) and reference gold (Au) surfaces was studied at different protein bulk concentrations over the temperature range 295-317 K, using quartz crystal microbalance with dissipation (QCM-D) and X-ray photoelectron spectroscopy (XPS). The QCM-D protein adsorption studies were complemented with polyclonal antibodies to examine the availability of protein sequences on the resulting protein layer. The QCM-D and XPS results show that the osteopontin surface mass uptake is larger on Au as compared to HA surfaces within the range of experimental conditions examined (protein bulk concentrations and temperature range), in accordance with the formation of a more compact protein film on Au. The specific antibody binding to the resulting adsorbed osteopontin layer as measured by QCM-D further confirms that the protein packing and conformational/orientational changes occurring during OPN adsorption on Au and HA are different, since fewer antibodies are observed to bind per OPN molecule on Au as compared to HA. The adsorption process on the respective surfaces was modeled using both the Langmuir and Hill adsorption isotherms, and from these isotherm curves, the Gibbs free energy, {Delta}G, of the osteopontin adsorption was determined. The estimated {Delta}G values indicate that the osteopontin molecules have a high affinity towards Au, while a lower affinity is observed between osteopontin and HA. By examining the changes in {Delta}G as a function of temperature, we additionally find that the osteopontin adsorption on HA and Au is endothermic and driven by an increase in entropy.

  5. Experimental research on dynamic operating characteristics of a novel silica gel-water adsorption chiller

    Institute of Scientific and Technical Information of China (English)

    WANG Dechang; WU Jingyi; WANG Ruzhu; DOU Weidong

    2007-01-01

    A novel silica gel-water adsorption chiller consisting of two adsorption/desorption chambers and an evaporator with one heat-pipe working chamber is experimentally studied.The dynamic operating characteristics of the chiller and the thermodynamic characteristics of the adsorber are obtained.The experimental results show that the dynamic operating characteristics of the chiller and the thermodynamic characteristics of the adsorber are satisfactory and that the cycle is a novel and effective adsorption cycle.A mass recovery process increases the cyclic adsorption capacity of the system and improves adaptability of the chiller to a lowgrade heat source.In addition,the experiment indicates that this novel chiller is highly suitable for an air conditioning system with a low dehumidification requirement or a system with a large cycle flowrate and an industrial cooling water system.

  6. Adsorption

    Directory of Open Access Journals (Sweden)

    Denis J.L. Guerra

    2016-09-01

    Full Text Available Nontronite is an important phyllosilicate with a high concentration of ferric iron in the octahedral layer. A new occurrence of Brazilian nontronite sample was used for the organofunctionalization process with 3-aminopropyltriethoxysilane. Due to the increment of basic centers attached to the pendant chains, the metal adsorption capability of the final chelating material, was found to be higher than its precursor. The ability of these materials to remove Pb2+, Mn2+, and Zn2+ from aqueous solutions was followed by a series of adsorption isotherms at room temperature and pH 6.0, in batch adsorption experiments in order to explain the adsorption mechanism. In order to evaluate the phyllosilicate samples as adsorbents in a dynamic system, a glass column was fulfilled with nontronite samples (1.5 g and it was fed with 2.1 mmol dm−3 divalent cations at pH 6.0. The energetic effects caused by metal cations adsorption were determined through calorimetric titrations. The effects of three divalent metals adsorption in the zero point of charge of each material were investigated.

  7. Site characteristics in metal organic frameworks for gas adsorption

    Science.gov (United States)

    Uzun, Alper; Keskin, Seda

    2014-02-01

    Metal organic frameworks (MOFs) are a new class of nanoporous materials that have many potential advantages over traditional nanoporous materials for several chemical technologies including gas adsorption, catalysis, membrane-based gas separation, sensing, and biomedical devices. Knowledge on the interaction of guest molecules with the MOF surface is required to design and develop these MOF-based processes. In this review, we examine the importance of identification of gas adsorption sites in MOFs using the current state-of-the-art in experiments and computational modeling. This review provides guidelines to design new MOFs with useful surface properties that exhibit desired performances, such as high gas storage capacity, and high gas selectivity.

  8. Characteristic Evaluation of Graphene Oxide for Bisphenol A Adsorption in Aqueous Solution

    Directory of Open Access Journals (Sweden)

    Thatchaphong Phatthanakittiphong

    2016-07-01

    Full Text Available This paper investigates the characteristics of graphene oxide (GO for Bisphenol A (BPA adsorption in water. Batch experiments on the influence of significant parameters were performed. While an improvement of the adsorption capacity of BPA was obtained by the increment of contact time and the initial BPA concentration, the increment of pH above 8, GO dosage, and temperature showed the reverse results. The thermodynamic study suggested that BPA adsorption on GO was an exothermic and spontaneous process. The kinetics was explained by the pseudo-second-order model which covers all steps of adsorption. The fit of the results with the Langmuir isotherm indicated the monolayer adsorption. At 298 K, the adsorption reached equilibrium within 30 min with the maximum adsorption capacity of 49.26 mg/g. The low BPA adsorption capacity of GO can be interpreted by the occurrence of oxygen-containing functional groups (OCFGs that are able to form hydrogen bonds with the surrounding OCFGs and water molecules. This effect inhibited the role of π–π interactions that are mainly responsible for the adsorption of BPA.

  9. Multifractal characteristics of Nitrogen adsorption isotherms from tropical soils

    Science.gov (United States)

    Vidal Vázquez, Eva; Paz Ferreiro, Jorge

    2010-05-01

    One of the primary methods used to characterize a wide range of porous materials, including soils, are gas adsorption isotherms. An adsorption isotherm is a function relating the amount of adsorbed gas or vapour to the respective equilibrium pressure, during pressure increase at constant temperature. Adsorption data allow easily estimates of specific surface area and also can provide a characterization of pore surface heterogeneity. Most of the properties and the reactivity of soil colloids are influenced by their specific surface area and by parameters describing the surface heterogeneity. For a restricted scale range, linearity between applied pressure and volume of adsorbate holds, which is the basis for current estimations of specific surface area. However, adsorption isotherms contain also non-linear segments of pressure versus volume so that evidence of multifractal scale has been demonstrated. The aim of this study was to analyze the multifractal behaviour of nitrogen adsorption isotherms from a set of tropical soils. Samples were collected form 54 horizons belonging to 19 soil profiles in the state of Minas Gerais, Brazil. The most frequent soil type was Oxisol, according to the Soil Survey Staff, equivalent to Latossolo in the Brazilian soil classification system. Nitrogen adsorption isotherms at standard 77 K were measured using a Thermo Finnigan Sorptomatic 1990 gas sorption analyzer (Thermo Scientific, Waltham, MA). From the raw data a distributions of mass along a support was obtained to perform multifractal analysis. The probability distribution was constructed by dividing the values of the measure in a given segment by the sum of the measure in the whole scale range. The box-counting method was employed to perform multifractal analysis. All the analyzed N2 adsorption isotherms behave like a multifractal system. The singularity spectra, f(α), showed asymmetric concave down parabolic shapes, with a greater tendency toward the left side, where moments

  10. Adsorption and desorption characteristics of lindane, carbofuran and methyl parathion on various Indian soils

    Energy Technology Data Exchange (ETDEWEB)

    Rama Krishna, K. [Department of Civil Engineering, Indian Institute of Technology Madras, Chennai 600036 (India)], E-mail: ramakrishnaiitm@gmail.com; Philip, Ligy [Department of Civil Engineering, Indian Institute of Technology Madras, Chennai 600036 (India)], E-mail: ligy@iitm.ac.in

    2008-12-30

    Adsorption and desorption characteristics of three insecticides on four Indian soils were studied. Insecticides used were representative of organochlorine, organophosphate, and carbomate groups. The order of adsorption of pesticides on soils was: lindane > methyl parathion > carbofuran. Compost soil had shown the maximum adsorption capacity. The order of adsorption capacity of various soils were: compost soil > clayey soil > red soil > sandy soil. Adsorption isotherms were better fitted to Freundlich model and K{sub f} values increased with increase in organic matter content of the soils. Thermodynamic parameters indicated favorable adsorption of all the three pesticides in four different soils. Adsorption was exothermic in nature. Distilled water desorbed 30-60% of adsorbed pesticides whereas; organic solvents were able to affect 50-80% of sorbed pesticides. Clay content and organic matter played a significant role in pesticide adsorption and desorption processes. Hysteresis effect was observed in red, clayey and compost soils. Hysteresis effect increased with increase in organic matter and clay content of the soils.

  11. [Characteristics of mitochondria and myocardium ultrastructure of rats following chronic incorporation of cesium radionuclides 137 Cs].

    Science.gov (United States)

    Gritsuk, A I; Matiukhina, T G; Koval', A N; Sergeenko, S M; Svergun, V T; Verner, A I; Gritsuk, N A

    2002-01-01

    Ultrastructure, tissue respiration and oxidative phosphorilation were studies in the myocardium of animals after chronic natural irradiation by 137Cs in quantities that can in reality threaten population of radionuclide-polluted regions. Decline in the respiratory activity of the myocardium and ultrastructural disorders can be attributed to the effects of ions of radioactive Cs which is also a potassium antagonist. A hypothesis has been put forward according to which cesium blocks potassium channels in mitochondria and thus changes the volume and configuration of internal mitochondrial membranes, and impacts the respiratory processes. In the opinion of the authors, these changes characterize the mitochondrial phase of apoptosis which, in the event of chronic exposure to radionuclides, is a compensatory-adaptive mechanism eliminating the least immutable subpopulation of cardiomyocites.

  12. Adsorption characteristics of bio-adsorbent on chromium(III) in industrial wastewater.

    Science.gov (United States)

    Lu, Zhufeng; Wang, Hongmei; Li, Jiayou; Yuan, Lixia; Zhu, Lianwen

    2015-01-01

    The removal of chromium(III) (Cr(III)) from industrial wastewater by various low-cost methods has been widely investigated. In this paper, a type of bio-adsorbent was prepared using rice straw modified by fermentation and simple chemical treatment. The aim is to detect the adsorption mechanism and characteristics on Cr(III) ions. The analysis shows that the bio-adsorbent possesses four modified characteristics for Cr(III) adsorption. The first one is the acquired physical adsorption involving concave and convex structures. The second one is the effects of the hydrogen bonding surface hydroxyl groups and the metal chromium ion with complexation. The third one is mainly caused by hydrophilic active groups that possess carboxyl and hydroxyl groups during microbial degradation to combine with ions. The final one is the bio-adsorbent had high adsorption for low concentration of Cr(III) ions. The highest removal of around 97.45% was obtained at pH 5.0, bio-adsorption dosage of 0.5 g L(-1), and initial Cr(III) concentration of 20 mg L(-1). The adsorption process followed the pseudo second-order model (R(2) > 0.99), while the isotherms were fitted to the Freundlich equation (68.1926 mg g(-1)), mainly by chemical adsorption. This study demonstrates the potential of using this biosorbent to remove Cr(III) from both synthetic and industrial wastewater.

  13. Adsorption

    Directory of Open Access Journals (Sweden)

    Sushmita Banerjee

    2017-05-01

    Full Text Available Application of saw dust for the removal of an anionic dye, tartrazine, from aqueous solutions has been investigated. The experiments were carried out in batch mode. Effect of the parameters such as pH, initial dye concentration and temperature on the removal of the dye was studied. Equilibrium was achieved in 70 min. Maximum adsorption of dye was achieved at pH 3. Removal percent was found to be dependent on the initial concentration of dye solution, and maximum removal was found to be 97% at 1 mg/L of tartrazine. The removal increases from 71% to 97% when the initial concentration of dye solution decreases from 15 mg/L to 1 mg/L. The equilibrium adsorption data were analyzed by Langmuir, Freundlich, Temkin and Dubinin–Radushkevich isotherm models. The (Langmuir adsorption capacity of the adsorbent is found to be 4.71 mg/g at 318 K. Kinetic modeling of the process of removal was carried out and the process of removal was found to follow a pseudo second order model and the value of rate constant for adsorption process was calculated as 2.7 × 10−3 g mg−1 min−1 at 318 K. The thermodynamic parameters such as change in free energy (ΔG°, enthalpy (ΔH° and entropy (ΔS° were determined and the negative values of ΔG° indicated that the process of removal was spontaneous at all values of temperatures. Further, the values of ΔH° indicated the endothermic nature of the process of removal.

  14. Adsorption characteristics of water vapor on honeycomb adsorbents

    Science.gov (United States)

    Wajima, Takaaki; Munakata, Kenzo; Takeishi, Toshiharu; Hara, Keisuke; Wada, Kouhei; Katekari, Kenichi; Inoue, Keita; Shinozaki, Yohei; Mochizuki, Kazuhiro; Tanaka, Masahiro; Uda, Tatsuhiko

    2011-10-01

    Recovery of tritium released into working areas in nuclear fusion plants is a key issue of safety. A large volume of air from tritium fuel cycle or vacuum vessel should be processed by air cleanup system (ACS). In ACS, tritium gas is oxidized by catalysts, and then tritiated water vapor is collected by adsorbents. This method can remove tritium effectively, whereas high throughput of air causes high-pressure drop in catalyst and adsorbent beds. In this study, the applicability of honeycomb-type adsorbents, which offers a useful advantage in terms of their low-pressure drop, to ACS was examined, in comparison with conventional pebble-type adsorbent. Honeycomb-type adsorbent causes far less pressure drop than pebble-type adsorbent beds. Adsorption capacity of water vapor on a honeycomb-type adsorbent is slightly lower than that on a pebble-type adsorbent, while adsorption rate of water vapor on honeycomb-type adsorbent is much higher than that of pebble-type adsorbent.

  15. Adsorption characteristics of copper, lead, zinc and cadmium ions by tourmaline

    Institute of Scientific and Technical Information of China (English)

    JIANG Kan; SUN Tie-heng; SUN Li-na; LI Hai-bo

    2006-01-01

    The adsorption characteristics of heavy metals: Cu(Ⅱ), Pb(Ⅱ), Zn(Ⅱ) and Cd(Ⅱ) ions on tourmaline were studied. Adsorption equilibrium was established. The adsorption isotherms of all the four metal ions followed well Langmuir equation. Tourmaline was found to remove heavy metal ions efficiently fiom aqueous solution with selectivity in the order of Pb(Ⅱ)>Cu(Ⅱ)>Cd(Ⅱ)>Zn(Ⅱ).The adsorption of metal ions by tourmaline increased with the initial concentration of metal ions increasing in the medium.Tourmaline could also increase pH value of metal solution. Themaximum heavy metal ions adsorbed by tourmaline was found to be 78.86, 154.08, 67.25, and 66.67 mg/g for Cu(Ⅱ), Pb(Ⅱ), Zn(Ⅱ) and Cd(Ⅱ), respectively. The temperature (25-55℃) had a small effect on the adsorption capacity of tourmaline. Competitive adsorption of Cu(Ⅱ), Pb(Ⅱ), Zn(Ⅱ) and Cd(Ⅱ) ions was also studied. The adsorption capacity of tourmaline for single metal decreased in the order of Pb>Cu>Zn>Cd and inhibition dominance observed in two metal systems was Pb>Cu, Pb>Zn, Pb>Cd, Cu>Zn, Cu>Cd, and Cd>Zn.

  16. Adsorption characteristics of bovine serum albumin onto alumina with a specific crystalline structure.

    Science.gov (United States)

    Kawashita, Masakazu; Hayashi, Junpei; Li, Zhixia; Miyazaki, Toshiki; Hashimoto, Masami; Hihara, Hiroki; Kanetaka, Hiroyasu

    2014-02-01

    Bone cement containing alumina particles with a specific crystalline structure exhibits the ability to bond with bone. These particles (AL-P) are mainly composed of delta-type alumina (δ-Al2O3). It is likely that some of the proteins present in the body environment are adsorbed onto the cement and influence the expression of its bioactivity. However, the effect that this adsorption of proteins has on the bone-bonding mechanism of bone cement has not yet been elucidated. In this study, we investigated the characteristics of the adsorption of bovine serum albumin (BSA) onto AL-P and compared them with those of its adsorption onto hydroxyapatite (HA), which also exhibits bone-bonding ability, as well as with those of adsorption onto alpha-type alumina (α-Al2O3), which does not bond with bone. The adsorption characteristics of BSA onto AL-P were very different from those onto α-Al2O3 but quite similar to those onto HA. It is speculated that BSA is adsorbed onto AL-P and HA by interionic interactions, while it is adsorbed onto α-Al2O3 by electrostatic attraction. The results suggest that the specific adsorption of albumin onto implant materials might play a role in the expression of the bone-bonding abilities of the materials.

  17. Adsorption and desorption characteristics of methamphetamine, 3,4-methylenedioxymethamphetamine, and pseudoephedrine in soils.

    Science.gov (United States)

    Pal, Raktim; Megharaj, Mallavarapu; Kirkbride, K Paul; Naidu, Ravi

    2015-06-01

    This work presents, for the first time, information on the adsorption-desorption characteristics of illicit drugs and precursors in soils and an estimation of their potential bioavailability. The experiment was conducted using a batch equilibrium technique for the parent drugs methamphetamine and 3,4-methylenedioxymethamphetamine (MDMA) and the precursor pseudoephedrine in three South Australian soils varying in physiochemical properties. The individual compounds exhibited different adsorption mechanisms in the test soils, and the results fitted better with the Freundlich isotherm model (r (2) ≥ 0.99). The maximum adsorption capacity was recorded for pseudoephedrine (2,000 μg g(-1)). However, pseudoephedrine recorded lower organic carbon normalized adsorption coefficient values (pseudoephedrine to be the most mobile compound in the soils under study, to have the highest availability for degradation of the three compounds, and to have the highest susceptibility to biotic degradation in test soils.

  18. Adsorption-desorption characteristics of phenol and reactive dyes from aqueous solution on mesoporous activated carbon prepared from waste tires.

    Science.gov (United States)

    Tanthapanichakoon, W; Ariyadejwanich, P; Japthong, P; Nakagawa, K; Mukai, S R; Tamon, H

    2005-04-01

    Liquid-phase adsorption-desorption characteristics and ethanol regeneration efficiency of an activated carbon prepared from waste tires and a commercial activated carbon were investigated. Water vapor adsorption experiments reveal that both activated carbons showed hydrophobic surface characteristics. Adsorption experiments reveal that the prepared activated carbon possessed comparable phenol adsorption capacity as the commercial one but clearly larger adsorption capacity of two reactive dyes, Black 5 and Red 31. It was ascertained that the prepared activated carbon exhibited less irreversible adsorption of phenol and the two dyes than its commercial counterpart. Moreover, ethanol regeneration efficiency of the prepared AC saturated with either dye was higher than that of the commercial AC. Because of its superior liquid-phase adsorption-desorption characteristics as well as higher ethanol regeneration efficiency, the prepared activated carbon is more suitable for wastewater treatment, especially for adsorbing similarly bulky adsorbates.

  19. Study on cyclic characteristics of the solar-powered adsorption cooling system

    Institute of Scientific and Technical Information of China (English)

    WU JingYi; LI Sheng; HU YanFei

    2009-01-01

    According to the typical variable heat source of solar energy and the unsteady adsorption process of adsorption chiller, the research of cyclic transient characteristics of the solar-powered adsorption cooling system is presented in this work. A mathematic model of the whole system including the model of adsorption chiller, which reveals the transient operation process of the solar-powered adsorption cooling system, is developed and verified by experimental data. On the basis of the simulated results, the transient characteristics and the overall performance of the system, not only in the traditional open cycle mode but also in closed cycle mode, are both analyzed theoretically. Furthermore, the influence of pa-rameters matching of components configuration and operation process on the cyclic characteristics of the system, such as the solar collector area, the water tank capacity and the chiller startup temperature, are discussed. The research in this work may play a very important role in optimizing the system cyclic process and improving the system adaptability especially under the condition of variable heat source.

  20. Study on cyclic characteristics of the solar-powered adsorption cooling system

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    According to the typical variable heat source of solar energy and the unsteady adsorption process of adsorption chiller,the research of cyclic transient characteristics of the solar-powered adsorption cooling system is presented in this work.A mathematic model of the whole system including the model of adsorption chiller,which reveals the transient operation process of the solar-powered adsorption cooling system,is developed and verified by experimental data.On the basis of the simulated results,the transient characteristics and the overall performance of the system,not only in the traditional open cycle mode but also in closed cycle mode,are both analyzed theoretically.Furthermore,the influence of parameters matching of components configuration and operation process on the cyclic characteristics of the system,such as the solar collector area,the water tank capacity and the chiller startup temperature,are discussed.The research in this work may play a very important role in optimizing the system cyclic process and improving the system adaptability especially under the condition of variable heat source.

  1. Adsorption characteristics of selected hydrophilic and hydrophobic micropollutants in water using activated carbon.

    Science.gov (United States)

    Nam, Seung-Woo; Choi, Dae-Jin; Kim, Seung-Kyu; Her, Namguk; Zoh, Kyung-Duk

    2014-04-15

    In this study, we investigated adsorption characteristics of nine selected micropollutants (six pharmaceuticals, two pesticides, and one endocrine disruptor) in water using an activated carbon. The effects of carbon dosage, contact time, pH, DOM (dissolved organic matter), and temperature on the adsorption removal of micropollutants were examined. Increasing carbon dosage and contact time enhanced the removal of micropollutants. Sorption coefficients of hydrophilic compounds (caffeine, acetaminophen, sulfamethoxazole, and sulfamethazine) fit a linear isotherm and hydrophobic compounds (naproxen, diclofenac, 2, 4-D, triclocarban, and atrazine) fit a Freundlich isotherm. The removal of hydrophobic pollutants and caffeine were independent of pH changes, but acetaminophen, sulfamethazine, and sulfamethoxazole were adsorbed by mainly electrostatic interaction with activated carbon and so were affected by pH. The decrease in adsorption removal in surface water samples was observed and this decrease was more significant for hydrophobic than hydrophilic compounds. The decline in the adsorption capacity in surface water samples is caused by the competitive inhibition of DOM with micropollutants onto activated carbon. Low temperature (5°C) also decreased the adsorption removal of micropollutants, and affected hydrophobic compounds more than hydrophilic compounds. The results obtained in this study can be applied to optimize the adsorption capacities of micropollutants using activated carbon in water treatment process.

  2. Adsorption characteristics of SO{sub 2}, NO by steam activated biomass chars

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Fei; Shu, Tong; Wang, Kuan; Lu, Ping [Nanjing Normal Univ. (China). School of Energy and Mechanical Engineering

    2013-07-01

    Wheat straw and rice husk collected from the suburb of Nanjing, China, were prepared to different kinds of steam activated biomass-based chars, and the adsorption characteristics of the biomass-based chars was carried out in a fixed bed reactor. The specific surface area and pore structure of different biomass chars were measured by nitrogen adsorption-desorption analysis instrument at 77K. The effects of biomass type, pyrolysis temperature, heating rate, activation temperature and concentration of SO{sub 2}, NO on the adsorption efficiency of SO{sub 2}, NO were analyzed. The results indicated that the steam activation has significant effects on the specific surface area, total pore volume and micro-morphology of biomass chars by improving the internal structure. The adsorption efficiency of SO{sub 2}, NO increased with the decreasing of SO{sub 2}, NO concentration in the experimental range. The optimal condition of char preparation (873K, fast pyrolysis) and steam activation (1,073K) was proposed based on the adsorption efficiency and adsorption volume of SO{sub 2}, NO. It builds a theoretical basis for industrial applications of biomass.

  3. A first-principles study of chlorine adsorption characteristics on -Cr2O3 nanostructures

    Indian Academy of Sciences (India)

    V Nagarajan; R Chandiramouli

    2015-10-01

    The structural stability, electronic and adsorption properties of chlorine on pristine, Zn, W and N-substituted -Cr2O3 nanostructures are successfully optimized and simulated with the help of density functional theory utilizing B3LYP/ LanL2DZ basis set. The structural stability of -Cr2O3 nanostructures are discussed in terms of formation energy. The electronic properties of pristine, Zn, W and N-substituted -Cr2O3 nanostructures are described with HOMO-LUMO gap, ionization potential and electron affinity. Dipole moment and point symmetry group of pristine, Zn, W and N-substituted -Cr2O3 nanostructures are reported. The adsorption characteristics of Cl2 on -Cr2O3 materials are investigated and the prominent adsorption sites of Cl2 on -Cr2O3 nanostructures are identified. The important parameters such as adsorbed energy, energy gap, average energy gap variation and Mulliken population analysis are used to find the favourable adsorption site of Cl2 on -Cr2O3 base material. The substitution of impurities such as Zn, W and N in -Cr2O3 nanostructures enhances the Cl2 adsorption characteristics in the mixed gas environment.

  4. Experimental comparison of adsorption characteristics of silica gel and zeolite in moist air

    Science.gov (United States)

    Xin, F.; Yuan, Z. X.; Wang, W. C.; Du, C. X.

    2016-05-01

    In this work, the macro adsorption characteristic of water vapor by the allochroic silica gel and the zeolite 5A and ZSM-5 were investigated experimentally. BET analysis method presented the difference of the porosity, the micro pore volume, and the specific surface area of the material. The dynamic and the equilibrium characteristics of the sample were measured thermo-gravimetrically in the moist air. In general, the ZSM-5 zeolite showed an inferior feature of the adsorption speed and the equilibrium concentration to the others. By comparison to the result of SAPO-34 zeolite in the open literature, the 5A zeolite showed some superiorities of the adsorption. The equilibrium concentration of the ZSM-5 zeolite was higher than that of the SAPO-34 calcined in the nitrogen, whereas it was lower than that calcined in the air. The adsorption isotherm was correlated and the relation of the isotherm to the microstructure of the material was discussed. With more mesopore volume involved, the zeolite presented an S-shaped isotherm in contrast to the exponential isotherm of the silica gel. In addition, the significance of the S-shaped isotherm for the application in adsorption heat pump has also been addressed.

  5. Experimental comparison of adsorption characteristics of silica gel and zeolite in moist air

    Science.gov (United States)

    Xin, F.; Yuan, Z. X.; Wang, W. C.; Du, C. X.

    2017-02-01

    In this work, the macro adsorption characteristic of water vapor by the allochroic silica gel and the zeolite 5A and ZSM-5 were investigated experimentally. BET analysis method presented the difference of the porosity, the micro pore volume, and the specific surface area of the material. The dynamic and the equilibrium characteristics of the sample were measured thermo-gravimetrically in the moist air. In general, the ZSM-5 zeolite showed an inferior feature of the adsorption speed and the equilibrium concentration to the others. By comparison to the result of SAPO-34 zeolite in the open literature, the 5A zeolite showed some superiorities of the adsorption. The equilibrium concentration of the ZSM-5 zeolite was higher than that of the SAPO-34 calcined in the nitrogen, whereas it was lower than that calcined in the air. The adsorption isotherm was correlated and the relation of the isotherm to the microstructure of the material was discussed. With more mesopore volume involved, the zeolite presented an S-shaped isotherm in contrast to the exponential isotherm of the silica gel. In addition, the significance of the S-shaped isotherm for the application in adsorption heat pump has also been addressed.

  6. Host cell protein adsorption characteristics during protein A chromatography.

    Science.gov (United States)

    Tarrant, Richard D R; Velez-Suberbie, M Lourdes; Tait, Andrew S; Smales, C Mark; Bracewell, Daniel G

    2012-07-01

    Protein A chromatography is a critical and 'gold-standard' step in the purification of monoclonal antibody (mAb) products. Its ability to remove >98% of impurities in a single step alleviates the burden on subsequent process steps and facilitates the implementation of platform processes, with a minimal number of chromatographic steps. Here, we have evaluated four commercially available protein A chromatography matrices in terms of their ability to remove host cell proteins (HCPs), a complex group of process related impurities that must be removed to minimal levels. SELDI-TOF MS was used as a screening tool to generate an impurity profile fingerprint for each resin and indicated a number of residual impurities present following protein A chromatography, agreeing with HCP ELISA. Although many of these were observed for all matrices there was a significantly elevated level of impurity binding associated with the resin based on controlled pore glass under standard conditions. Use of null cell line supernatant with and without spiked purified mAb demonstrated the interaction of HCPs to be not only with the resin back-bone but also with the bound mAb. A null cell line column overload and sample enrichment method before 2D-PAGE was then used to determine individual components associated with resin back-bone adsorption. The methods shown allow for a critical analysis of HCP removal during protein A chromatography. Taken together they provide the necessary process understanding to allow process engineers to identify rational approaches for the removal of prominent HCPs.

  7. Radionuclide cystogram

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/article/003832.htm Radionuclide cystogram To use the sharing features on this page, please enable JavaScript. A radionuclide cystogram is a special imaging test called a nuclear ...

  8. Activated Carbon Adsorption Characteristics of Multi-component Volatile Organic compounds in a Fixed Bed Adsorption Bed

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Jong Hoon; Rhee, Young Woo [Chungnam National University, Daejeon (Korea, Republic of); Lee, Sihyun [Korea Institute of Energy Research, Daejeon (Korea, Republic of)

    2016-04-15

    This study aims to examine absorption characteristics of toluene, isopropyl alcohol (IPA), ethyl acetate (EA), and ternary-compounds, all of which are widely used in industrial processes, by means of four types of commercial activated carbon substances. It turned out that among the three types of volatile organic compounds, the breakthrough point of activated carbon and that of IPA, whose affinity was the lowest, were the lowest, and then that of EA and that of toluene in the order. With the breakthrough point of IPA, which was the shortest, as the standard, changes in the breakthrough points of unary-compounds, binary-compounds, and ternary-compounds were examined. As a result, it turned out that the larger the number of elements, the lower the breakthrough point. This resulted from competitive adsorption, that is, substitution of substances with a low level of affinity with those with a high level of affinity. Hence, the adsorption of toluene-IPA-EA and ternary-compounds require a design of the activated carbon bed based on the breakthrough of IPA, and in the design of activated carbon beds in actual industries as well, a substance whose level of affinity is the lowest needs to be the standard.

  9. Adsorption characteristics of hexavalent chromium on HCB/TiO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Li; Zhang, Yonggang, E-mail: 13502182420@163.com

    2014-10-15

    Graphical abstract: - Highlights: • Sol–gel method was adopted to prepare HCB/TiO{sub 2}. • Its adsorption performance of Cr(VI) was investigated. • The maximum adsorption capacity for Cr(VI) was at 27.33 mg g{sup −1} in an acidic medium. • The value is worth comparable with other low-cost adsorbents. - Abstract: Sol–gel method was adopted to prepare HCB/TiO{sub 2} and its adsorption ability of hexavalent chromium, Cr(VI), and removal from aqueous solution were investigated. The samples were characterized by Power X-ray diffraction (XRD) and a transmission electron microscope (TEM) which showed that the TiO{sub 2} was deposited on the surface of HCB. FTIR was used to identify the changes of the surface functional groups before and after adsorption. Potentiometric titration method was used to characterize the zero charge (pH{sub pzc}) characteristics of the surface of HCB/TiO{sub 2} which showed more acidic functional groups containing. Batch experiments showed that initial pH, absorbent dosage, contact time and initial concentration of Cr(VI) were important parameters for the Cr(VI) adsorption studies. The Freundlich isotherm model better reflected the experimental data better. Cr(VI) adsorption process followed the pseudo-second order kinetic model, which illustrated chemical adsorption. The thermodynamic parameters, such as Gibbs free energy (ΔG), changes in enthalpy change (ΔH) and changes in entropy change (ΔS) were also evaluated. Negative value of free energy occurred at temperature range of 25–45 °C, so Cr(VI) adsorption by HCB/TiO{sub 2} is spontaneous. Desorption results showed that the adsorption capacity could maintain 80% after five cycles. The maximum adsorption capacity for Cr(VI) was at 27.33 mg g{sup −1} in an acidic medium, of which the value is worth comparable with other low-cost adsorbents.

  10. Mercury oxidation and adsorption characteristics of potassium permanganate modified lignite semi-coke

    Institute of Scientific and Technical Information of China (English)

    Huawei Zhang; Jitao Chen; Peng Liang; Li Wang

    2012-01-01

    The adsorption characteristics of virgin and potassium permanganate modified lignite semi-coke (SC) for gaseous Hg0 were investigated in an attempt to produce more effective and lower price adsorbents for the control of elemental mercury emission.Brunauer-Emmett-Teller (BET) measurements,X-ray powder diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) were used to analyze the surface physical and chemical properties of SC,Mn-SC and Mn-H-SC before and after mercury adsorption.The results indicated that potassium permanganate modification had significant influence on the properties of semi-coke,such as the specific surface area,pore structure and surface chemical functional groups.The mercury adsorption efficiency of modified semi-coke was lower than that of SC at low temperature,but much higher at high temperature.Amorphous Mn7+,Mn6+ and Mn4+ on the surface of Mn-SC and Mn-H-SC were the active sites for oxidation and adsorption of gaseous Hg0,which oxidized the elemental mercury into Hg2+ and captured it.Thermal treatment reduced the average oxidation degree of Mnx+ on the surface of Mn-SC from 3.80 to 3.46.However,due to the formation of amorphous MnOx,the surface oxidation active sites for gaseous Hg0 increased,which gave Mn-H-SC higher mercury adsorption efficiency than that of Mn-SC at high temperature.

  11. Mercury oxidation and adsorption characteristics of potassium permanganate modified lignite semi-coke.

    Science.gov (United States)

    Zhang, Huawei; Chen, Jitao; Liang, Peng; Wang, Li

    2012-01-01

    The adsorption characteristics of virgin and potassium permanganate modified lignite semi-coke (SC) for gaseous Hg0 were investigated in an attempt to produce more effective and lower price adsorbents for the control of elemental mercury emission. Brunauer-Emmett-Teller (BET) measurements, X-ray powder diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) were used to analyze the surface physical and chemical properties of SC, Mn-SC and Mn-H-SC before and after mercury adsorption. The results indicated that potassium permanganate modification had significant influence on the properties of semi-coke, such as the specific surface area, pore structure and surface chemical functional groups. The mercury adsorption efficiency of modified semi-coke was lower than that of SC at low temperature, but much higher at high temperature. Amorphous Mn7+, Mn6+ and Mn4+ on the surface of Mn-SC and Mn-H-SC were the active sites for oxidation and adsorption of gaseous Hg0, which oxidized the elemental mercury into Hg2+ and captured it. Thermal treatment reduced the average oxidation degree of Mn(x+) on the surface of Mn-SC from 3.80 to 3.46. However, due to the formation of amorphous MnOx, the surface oxidation active sites for gaseous Hg0 increased, which gave Mn-H-SC higher mercury adsorption efficiency than that of Mn-SC at high temperature.

  12. Characteristics and mechanisms of nickel adsorption on biochars produced from wheat straw pellets and rice husk.

    Science.gov (United States)

    Shen, Zhengtao; Zhang, Yunhui; McMillan, Oliver; Jin, Fei; Al-Tabbaa, Abir

    2017-05-01

    The adsorption characteristics and mechanisms of Ni(2+) on four-standard biochars produced from wheat straw pellets (WSP550, WSP700) and rice husk (RH550, RH700) at 550 and 700 °C, respectively, were investigated. The kinetic results show that the adsorption of Ni(2+) on the biochars reached an equilibrium within 5 min. The increase of the solid to liquid ratio resulted in an increase of Ni(2+) removal percentage but a decrease of the adsorbed amount of Ni(2+) per weight unit of biochar. The Ni(2+) removal percentage increased with the increasing of initial solution pH values at the range of 2-4, was relatively constant at the pH range of 4-8, and significantly increased to ≥98% at pH 9 and stayed constantly at the pH range of 9-10. The calculated maximum adsorption capacities of Ni(2+) for the biochars follow the order of WSP700 > WSP550 > RH700 > RH550. Both cation exchange capacity and pH of biochar can be a good indicator of the maximum adsorption capacity for Ni(2+) showing a positively linear and exponential relationship, respectively. This study also suggests that a carefully controlled standardised production procedure can make it reliable to compare the adsorption capacities between different biochars and investigate the mechanisms involved.

  13. Adsorption characteristic of bensulfuron-methyl at variable added Pb2+ concentrations on paddy soils

    Institute of Scientific and Technical Information of China (English)

    WU Weihong; WANG Haizhen; XU Jianming; XIE Zhengmiao

    2009-01-01

    The combined pollution of heavy metal Pb2+ and bensulfuron-methyl (BSM), originating from chemical herbicides, in agro-ecological environments has become commonplace in southern China.The adsorption of BSM on three paddy soils in the presence of Pb2+ with different levels was examined by the batch equilibration and high-performance liquid chromatograph (HPLC) techniques.Results indicated that adsorption of BSM could accurately be described by a Freundlich isotherm equation with correlation constant (R) > 0.98, irrespective of the presence of spiked Pb2+.Of the various factors influencing BSM sorption, soil pH appeared to be the most influential.The constant Kf of Freundlich isotherm equation tended to increase with increasing Pb2+ concentration in soil which indicated that the spiked of Pb2+ in paddy soils would promote the sorption of BSM.The ΔGθ of BSM in three paddy soils was less than 40 kJ/mol in all treatments, indicating adsorption of BSM is mainly physical in nature.The elution of soil dissolved organic matter (DOM) enhanced the adsorption of BSM in paddy soils.We suggested that the mechanisms involved in the promotion effects of the spiked Pb2+ on adsorption of BSM might be the modified surface characteristics of paddy soil solids due to the soil acidification and the increase of soil organic matter concentration because of DOM binding.

  14. Adsorption-desorption characteristics of mercury in paddy soils of China.

    Science.gov (United States)

    Jing, Y D; He, Z L; Yang, X E

    2008-01-01

    Mercury (Hg) has received considerable attention because of its association with various human health problems. Adsorption-desorption behavior of Hg at contaminated levels in two paddy soils was investigated. The two representative soils for rice production in China, locally referred to as a yellowish red soil (YRS) and silty loam soil (SLS) and classified as Gleyi-Stagnic Anthrosols in FAO/UNESCO nomenclature, were respectively collected from Jiaxin County and Xiasha District of Hangzhou City, Zhejiang Province. The YRS adsorbed more Hg(2+) than the SLS. The characteristics of Hg adsorption could be described by the simple Langmuir adsorption equation (r2 = 0.999 and 0.999, P adsorption values (Xm) that were obtained from the simple Langmuir model were 111 and 213 mg Hg(2+) kg(-1) soil, respectively, for the SLS and YRS. Adsorption of Hg(2+) decreased soil pH by 0.75 unit for the SLS soil and 0.91 unit for the YRS soil at the highest loading. The distribution coefficient (kd) of Hg in the soil decreased exponentially with increasing Hg(2+) loading. After five successive desorptions with 0.01 mol L(-1) KCl solution (pH 5.4), 0 to 24.4% of the total adsorbed Hg(2+) in the SLS soil was desorbed and the corresponding value of the YRS soil was 0 to 14.4%, indicating that the SLS soil had a lower affinity for Hg(2+) than the YRS soil at the same Hg(2+) loading. Different mechanisms are likely involved in Hg(2+) adsorption-desorption at different levels of Hg(2+) loading and between the two soils.

  15. [Characteristics of orthophosphate adsorption on ferric-alum residuals (FARs) from drinking water treatment plant].

    Science.gov (United States)

    Wang, Chang-Hui; Pei, Yuan-Sheng

    2011-08-01

    Batch tests have been used to investigate the characteristics of orthophosphate adsorption on ferric-alum residuals (FARs) from drinking water treatment plant. ICP, SEM and XRD analyses confirm that the FARs enriched in Fe and Al elements and presented amorphism structure. Orthophosphate sorption by the FARs can be described by the pseudo-second-order kinetics equation. Fine adsorption effects of the FARs were found under lower pH values, particularly a 40.13% drop of the adsorptive capacity from pH 4.6 to pH 7.6. The FARs with grain sizes of 0.6-0.9 mm had the highest adsorption capacity of orthophosphate. Experimental data could be better fitted by the isotherm models of Langmuir (R2 = 0.9736) and Freundlich (R2 = 0.9916). The maximal adsorptive capacity reached 45.45 mg x g(-1) estimated from Langmuir isotherm model. Compared with other natural and industrial materials, FARs has relatively higher adsorption capacity. Under similar testing conditions, it was found that only about 10% orthophosphate could be desorbed from the FARs. Further study demonstrated that the mean energy of orthophosphate sorption on the FARs was 13.36 kJ x mol(-1) and the deltaH0 > 0, deltaS0 > 0 and deltaG0 < 0, which indicated that orthophosphate sorption on the FARs was a spontaneously endothermic chemical reaction. It can be therefore highly valued that the FARs may be applied to phosphate removal from wastewater and surface water.

  16. Investigation on the adsorption characteristics of anserine on the surface of colloidal silver nanoparticles.

    Science.gov (United States)

    Thomas, S; Maiti, N; Mukherjee, T; Kapoor, S

    2013-08-01

    The surface-enhanced Raman scattering (SERS) studies of anserine (beta-alanyl-N-methylhistidine) was carried out on colloidal silver nanoparticles to understand its adsorption characteristics. The experimentally observed Raman bands were assigned based on the results of DFT calculations. The studies suggest that the interaction of anserine is primarily through the carboxylate group with the imidazole ring in an upright position with respect to the silver surface. Concentration dependent SERS studies suggest a change in orientation at sub-monolayer concentration.

  17. Cosmogenic radionuclides

    CERN Document Server

    Beer, Jürg; Von Steiger, R

    2012-01-01

    Cosmogenic radionuclides are radioactive isotopes which are produced by natural processes and distributed within the Earth system. With a holistic view of the environment the authors show in this book how cosmogenic radionuclides can be used to trace and to reconstruct the history of a large variety of processes. They discuss the way in which cosmogenic radionuclides can assist in the quantification of complex processes in the present-day environment. This book aims to demonstrate to the reader the strength of analytic tools based on cosmogenic radionuclides, their contribution to almost any f

  18. An Investigation of Fractal Characteristics of Marine Shales in the Southern China from Nitrogen Adsorption Data

    Directory of Open Access Journals (Sweden)

    Jian Xiong

    2015-01-01

    Full Text Available We mainly focus on the Permian, Lower Cambrian, Lower Silurian, and Upper Ordovician Formation; the fractal dimensions of marine shales in southern China were calculated using the FHH fractal model based on the low-pressure nitrogen adsorption analysis. The results show that the marine shales in southern China have the dual fractal characteristics. The fractal dimension D1 at low relative pressure represents the pore surface fractal characteristics, whereas the fractal dimension D2 at higher relative pressure describes the pore structure fractal characteristics. The fractal dimensions D1 range from 2.0918 to 2.718 with a mean value of 2.4762, and the fractal dimensions D2 range from 2.5842 to 2.9399 with a mean value of 2.8015. There are positive relationships between fractal dimension D1 and specific surface area and total pore volume, whereas the fractal dimensions D2 have negative correlation with average pore size. The larger the value of the fractal dimension D1 is, the rougher the pore surface is, which could provide more adsorption sites, leading to higher adsorption capacity for gas. The larger the value of the fractal dimension D2 is, the more complicated the pore structure is, resulting in the lower flow capacity for gas.

  19. Adsorption Characteristics of Water and Silica Gel System for Desalination Cycle

    KAUST Repository

    Cevallos, Oscar R.

    2012-07-01

    An adsorbent suitable for adsorption desalination cycles is essentially characterized by a hydrophilic and porous structure with high surface area where water molecules are adsorbed via hydrogen bonding mechanism. Silica gel type A++ possesses the highest surface area and exhibits the highest equilibrium uptake from all the silica gels available in the market, therefore being suitable for water desalination cycles; where adsorbent’s adsorption characteristics and water vapor uptake capacity are key parameters in the compactness of the system; translated as feasibility of water desalination through adsorption technologies. The adsorption characteristics of water vapor onto silica gel type A++ over a temperature range of 30 oC to 60 oC are investigated in this research. This is done using water vapor adsorption analyzer utilizing a constant volume and variable pressure method, namely the Hydrosorb-1000 instrument by Quantachrome. The experimental uptake data is studied using numerous isotherm models, i. e. the Langmuir, Tóth, generalized Dubinin-Astakhov (D-A), Dubinin-Astakhov based on pore size distribution (PSD) and Dubinin-Serpinski (D-Se) isotherm for the whole pressure range, and for a pressure range below 10 kPa, proper for desalination cycles; isotherms type V of the International Union of Pure and Applied Chemistry (IUPAC) classification were exhibited. It is observed that the D-A based on PSD and the D-Se isotherm models describe the best fitting of the experimental uptake data for desalination cycles within a regression error of 2% and 6% respectively. All isotherm models, except the D-A based on PSD, have failed to describe the obtained experimental uptake data; an empirical isotherm model is proposed by observing the behavior of Tóth and D-A isotherm models. The new empirical model describes the water adsorption onto silica gel type A++ within a regression error of 3%. This will aid to describe the advantages of silica gel type A++ for the design of

  20. Adsorption Characteristics of Ion-Exchanged ZSM-5 Zeolites for CO(2)/N(2) Mixtures.

    Science.gov (United States)

    Katoh, Masahiro; Yoshikawa, Takushi; Tomonari, Takao; Katayama, Kazuyuki; Tomida, Tahei

    2000-06-01

    Adsorption characteristics of alkali metal ion-exchanged ZSM-5 zeolites, M-ZSM-5 (M=Li, Na, K, Rb, and Cs), for CO(2)/N(2) mixtures were investigated by a column method and IR study. It was shown that CO(2) was adsorbed from CO(2)/N(2) mixtures on M-ZSM-5 zeolites by two types of adsorbtion at temperatures below 333 K. One was a weak adsorption due to interaction with the wall of ZSM-5, and the other was a strong adsorption caused by interactions with the cation of ZSM-5. IR-spectra of gases adsorbed at various temperatures revealed that the CO(2) were strongly adsorbed on M-ZSM-5 in several ways, which seemed to be caused by different adsorption sites. At temperatures above 373 K, almost all CO(2) adsorbed were on cation sites, while N(2) coadsorbed with CO(2) was shown to interact with the wall of ZSM-5 under all experimental conditions. Copyright 2000 Academic Press.

  1. [Heavy metals contents and Hg adsorption characteristics of mosses in virgin forest of Gongga Mountain].

    Science.gov (United States)

    Liang, Peng; Yang, Yong-Kui; He, Lei; Wang, Ding-Yong

    2008-06-01

    Seven main moss species in the Hailuogou virgin forest of Gongga Mountain were sampled to determine their heavy metals (Hg, Cr, Cd, Ni, Pb, Cu, Mn, Zn and Fe) content, and two widely distributed species, Pleurozium schreberi (Brid.) Mitt. and Racomitrium laetum Besch., were selected to study their Hg adsorption characteristics. The results showed that the heavy metals contents in the mosses were lower than the background values in Europe and America, except that the Cd had a comparable value, which indicated that the atmosphere in study area was not polluted by heavy metals and good in quality. The Hg adsorption by P. schreberi and R. laetum was an initiative and rapid process, with the equilibrium reached in about two hours, and could be well fitted by Freundlich and Langmuir equations. Based on Langmuir equation, the maximum Hg adsorption capacities of P. schreberi and R. laetum were 15.24 and 8.19 mg x g(-1), respectively, suggesting that the two mosses had a good capacity of Hg adsorption, and could be used as the bio-monitors of atmospheric Hg pollution.

  2. CR-100 synthetic zeolite adsorption characteristics toward Northern Banat groundwater ammonia.

    Science.gov (United States)

    Tomić, Željko; Kukučka, Miroslav; Stojanović, Nikoleta Kukučka; Kukučka, Andrej; Jokić, Aleksandar

    2016-10-14

    The adsorption characteristics of synthetic zeolite CR-100 in a fixed-bed system using continuous flow of groundwater containing elevated ammonia concentration were examined. The possibilities for adsorbent mass calculation throughout mass transfer zone using novel mathematical approach as well as zeolite adsorption capacity at every sampling point in time or effluent volume were determined. The investigated adsorption process consisted of three clearly separated steps indicated to sorption kinetics. The first step was characterized by decrease and small changes in effluent ammonia concentration vs. experiment time and quantity of adsorbed ammonia per mass unit of zeolite. The consequences of this phenomenon were showed in the plots of the Freundlich and the Langmuir isotherm models through a better linear correlation according as graphical points contingent to the first step were not accounted. The Temkin and the Dubinin-Radushkevich isotherm models showed the opposite tendency with better fitting for overall measurements. According to the obtained isotherms parameter data, the investigated process was found to be multilayer physicochemical adsorption, and also that synthetic zeolite CR-100 is a promising material for removal of ammonia from Northern Banat groundwater with an ammonia removal efficiency of 90%.

  3. Effects of Surface Treatment of Activated Carbon on Its Surface and Cr(VI) Adsorption Characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Park, Soo Jin; Jang, Yu Sin [Advanced Materials Division., Korea Research Institute of Chimical Technology, Taejon (Korea)

    2001-04-01

    In this work, the effect of surface treatments on activated carbons (ACs) has been studied in the context of gas and liquid adsorption behaviors. The chemical solutions used in this experiment were 35% sodium hydroxide, and these were used for the acidic and basic treatments, respectively. The surface properties have been determined by pH, acid-base values, and FT-IR. The adsorption isotherms of Cr(VI) ion on activated carbons have been studied with the 5 mg/l concentration at ambient temperature. N{sub 2} adsorption isotherm characteristics, which include the specific surface area, micro pore volume, and microporosity, were determined by BET and Boer's-plot methods. In case of the acidic treatment of activated carbons, it was observed that the adsorption of Cr(VI) ion was more effective due to the increase acid value (or acidic functional group) of activated carbon surfaces. However, the basic treatment on activated carbons was caused no significant effects, probably due to the decreased specific surface area and total pore volume. 27 refs., 7 figs., 4 tabs.

  4. Analyzing adsorption characteristics of CO2, N2 and H2O in MCM-41 silica by molecular simulation

    Science.gov (United States)

    Chang, Shing-Cheng; Chien, Shih-Yao; Chen, Chieh-Li; Chen, Cha'o.-Kuang

    2015-03-01

    The adsorption characteristics of carbon dioxide, nitrogen and water molecules in MCM-41 mesoporous molecular sieve have been investigated by the molecular simulation. We evaluate the pressure-adsorption isotherms and adsorption density profiles under variant gas pressure, operating temperature and mesopore radius of MCM-41 by the grand canonical Monte Carlo simulation. According to the calculated adsorption energy distributions, the adsorption mechanisms of gas in MCM-41 are mainly divided into three types, namely "surface adsorption" on the pore wall, "multilayer adsorption" on the adsorbed gas molecules and "molecular self-aggregation" near the pore center. In addition, the adsorption characteristics of water molecules in MCM-41 are found to be quite different from those of carbon dioxide and nitrogen due to the hydrogen bonds effect. The results indicate that the MCM-41 is practicable in engineering application for the capture, storage, and re-use of water molecules, since it is temperature-sensitive and can achieve significant adsorption loadings within a small range of pressure values via the capillary condensation phenomena.

  5. Study on characteristics of CdS quantum dot-sensitized solar cells prepared by successive ionic layer adsorption and reaction with different adsorption times

    Science.gov (United States)

    Jeong, Myeong-Soo; Son, Min-Kyu; Kim, Soo-Kyoung; Park, Songyi; Prabakar, Kandasamy; Kim, Hee-Je

    2014-05-01

    Cadmium sulfide (CdS) quantum dots (QDs) were adsorbed on a titanium dioxide (TiO2) nanoporous film by successive ionic layer adsorption and reaction (SILAR) method with different adsorption times to study the influences of different SILAR adsorption times on CdS quantum dot-sensitized solar cells (QDSCs). The optical properties of CdS sensitized TiO2 films were studied by scanning electron microscopy and UV-Vis absorbance spectroscopy. The particle size of the CdS QDs was approximated using the effective mass approximation theory from the absorbance spectra. The photovoltaic characteristics of the CdS QDSCs were analyzed by I- V characteristics and electrochemical impedance spectroscopy under air mass 1.5 illumination. As a result, the particle size of the CdS QDs became larger and light harvesting was enhanced with increasing SILAR adsorption time. The maximum photovoltaic conversion efficiency of the CdS QDSCs (1.86%) was obtained at the SILAR adsorption time of 30 min with the highest short circuit current density and lowest charge transfer resistance.

  6. Mercury adsorption characteristics of HBr-modified fly ash in an entrained-flow reactor.

    Science.gov (United States)

    Zhang, Yongsheng; Zhao, Lilin; Guo, Ruitao; Song, Na; Wang, Jiawei; Cao, Yan; Orndorff, William; Pan, Wei-ping

    2015-07-01

    In this study, the mercury adsorption characteristics of HBr-modified fly ash in an entrained-flow reactor were investigated through thermal decomposition methods. The results show that the mercury adsorption performance of the HBr-modified fly ash was enhanced significantly. The mercury species adsorbed by unmodified fly ash were HgCl2, HgS and HgO. The mercury adsorbed by HBr-modified fly ash, in the entrained-flow reactor, existed in two forms, HgBr2 and HgO, and the HBr was the dominant factor promoting oxidation of elemental mercury in the entrained-flow reactor. In the current study, the concentration of HgBr2 and HgO in ash from the fine ash vessel was 4.6 times greater than for ash from the coarse ash vessel. The fine ash had better mercury adsorption performance than coarse ash, which is most likely due to the higher specific surface area and longer residence time.

  7. Electric and Adsorption Characteristics of Nanocrystalline V-(N, He Coatings

    Directory of Open Access Journals (Sweden)

    Alexey G. Guglya

    2009-01-01

    Full Text Available This paper studies the structure, temperature dependences of electric resistance, and adsorption properties of nanoporous three-component V-(N, He coatings. The coatings were produced using the technique of ion beam assisted deposition, in particular, deposition of vanadium onto a titanium substrate simultaneously bombarding it with N2+He ions of 30 keV. It is shown, in contrast to V-N composites that have negative TCR (temperature coefficient of resistance, that the V-(N, He coatings have negative TCR only in the temperature range of 250 to 350∘C. A specific surface of pores and adsorption characteristics of V-(N, He composites depend on preliminary treatment of a titanium surface. A coating deposited onto an untreated substrate has specific surface of 25.5 m2/g. The preliminary irradiation of titanium with N2+He beam up to a dose of 6 × 1017 ion/cm2 provides the increase in surface area up to 57.6 m2/g. The preliminary ion bombardment provides a considerable increase in hydrogen adsorption capacity of coatings. Especially, such impact is noticeable at the room temperature, when the amount of hydrogen absorbed by a coating that was applied onto a treated surface is more than three times of that absorbed by a coating that was deposited onto nonexposed titanium.

  8. Adsorption characteristics of activated carbon fibers (ACFs) for toluene: application in respiratory protection.

    Science.gov (United States)

    Balanay, Jo Anne G; Bartolucci, Alfred A; Lungu, Claudiu T

    2014-01-01

    Granular activated carbon (GAC) is currently the standard adsorbent in respirators against several gases and vapors because of its efficiency, low cost, and available technology. However, a drawback of GAC due to its granular form is its need for containment, adding weight and bulkiness to respirators. This makes respirators uncomfortable to wear, resulting in poor compliance in their use. Activated carbon fibers (ACF) are considered viable alternative adsorbent materials for developing thinner, light-weight, and efficient respirators because of their larger surface area, lighter weight, and fabric form. This study aims to determine the critical bed depth and adsorption capacity of different types of commercially available ACFs for toluene to understand how thin a respirator can be and the service life of the adsorbents, respectively. ACF in cloth (ACFC) and felt (ACFF) forms with three different surface areas per form were tested. Each ACF type was challenged with six concentrations of toluene (50, 100, 200, 300, 400, 500 ppm) at constant air temperature (23°C), relative humidity (50%), and airflow (16 LPM) at different adsorbent weights and bed depths. Breakthrough data were obtained for each adsorbent using gas chromatography with flame ionization detector. The ACFs' surface areas were measured by an automatic physisorption analyzer. The results showed that ACFC has a lower critical bed depth and higher adsorption capacity compared to ACFF with similar surface area for each toluene concentration. Among the ACF types, ACFC2000 (cloth with the highest measured surface area of 1614 ± 5 m(2)/g) has one of the lowest critical bed depths (ranging from 0.11-0.22 cm) and has the highest adsorption capacity (ranging from 595-878 mg/g). Based on these studied adsorption characteristics, it is concluded that ACF has great potential for application in respiratory protection against toluene, particularly the ACFC2000, which is the best candidate for developing thinner and

  9. Microorganisms and radionuclides in the environment

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, Yoshitomo [Central Research Inst. of Electric Power Industry, Abiko, Chiba (Japan)

    2002-11-01

    The influence of microorganisms on the behavior of radionuclides in the subsurface environment is one of the factors to be concerned with for the safety assessment of the geological disposal of radioactive waste. It is considered that the important microbiological aspects with respect to radionuclide behavior are biological adsorption, oxidation-reduction and complex formation between organic matter and radionuclides. These phenomena with respect to radionuclides, especially actinides, in the environment should be understood. A description of two studies, illustrating these points are presented. (author)

  10. Tailoring oxide properties: An impact on adsorption characteristics of molecules and metals

    Science.gov (United States)

    Honkala, Karoliina

    2014-12-01

    -metal interface and their effect on the adsorption characteristics of water and Au are summarized. Finally, more limited computational literature on transition metal (TM) doped CaO(100) and MgO(100) surfaces is presented. Again, Au is used as a probe species. Similar to metal-supported MgO films, Au binds more strongly than on undoped CaO(100) and becomes negatively charged. The discussion focuses on rationalization of Au adsorption with the help of Born-Haber cycle, which reveals that the so-called redox energy including the electron transfer from the dopant to the Au atom together with the simultaneous structural relaxation of lattice atoms is responsible for enhanced binding. In addition, adsorption energy dependence on the position and type of the dopant is summarized.

  11. Improving precursor adsorption characteristics in ATR-FTIR spectroscopy with a ZrO2 nanoparticle coating

    Science.gov (United States)

    Park, Jaeseo; Mun, Jihun; Shin, Jae-Soo; Kim, Jongho; Park, Hee Jung; Kang, Sang-Woo

    2017-02-01

    Nanoparticles were applied to a crystal surface to increase its precursor adsorption efficiency in an attenuated total reflection Fourier transform infrared (ATR-FTIR) spectrometer. Nanoparticles with varying dispersion stabilities were employed and the resulting precursor adsorption characteristics were assessed. The size of the nanoparticles was FTIR spectroscopy. Consequently, when ZrO2 nanoparticle solutions with the best dispersion stabilities (pH 3 and 11) were applied to the adsorption crystal surface, the measurement efficiency of ATR-FTIR spectroscopy improved by ˜200 and 300%, respectively.

  12. Adsorption characteristics of zinc ions on sodium dodecyl sulfate in process of micellar-enhanced ultrafiltration

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    To separate zinc ions from aqueous solution efficiently, micellar-enhanced ultrafiltration(MEUF) of hollow ultrafiltration membrane was used with sodium dodecyl sulfate(SDS) as surfactant. The formation of micellar and the adsorption mechanism were investigated, including the influence of the ratio of SDS to zinc ions on the micelle quantity, the micelle ratio, the gross adsorptive capacity, the rejection of zinc ions and the adsorption isotherm law. The results show that the rejection rate of zinc ions reaches 97% and the adsorption of zinc ions on SDS conforms to the Langmuir adsorption isotherm and the adsorption is a chemical adsorption process.

  13. Characteristics and Stability of Mercury Vapor Adsorption over Two Kinds of Modified Semicoke

    Directory of Open Access Journals (Sweden)

    Zhang Huawei

    2014-01-01

    Full Text Available In an attempt to produce effective and lower price gaseous Hg0 adsorbents, two methods of HCl and KMnO4/heat treatment were used respectively for the surface modification of liginite semicoke from inner Mongolia. The different effects of modification process on the surface physical and chemical properties were analyzed. The characteristics and stability of mercury vapor adsorption over two kinds of modified semicoke were investigated. The results indicated that modification process caused lower micropore quantity and volume capacity of semicoke; the C-Cl functional groups, C=O bond and delocalized electron π on the surface of Cl-SC, the amorphous higher valency Mnx+, and O=C–OH functional groups on the surface of Mn-H-SC were the active sites for oxidation and adsorption of gaseous Hg0. Modification process led to higher mercury removal efficiency of semicoke at 140°C and reduced the stability of adsorbed mercury of semicoke in simulated water circumstance simultaneously.

  14. Characteristics and stability of mercury vapor adsorption over two kinds of modified semicoke.

    Science.gov (United States)

    Huawei, Zhang; Xiuli, Liu; Li, Wang; Peng, Liang

    2014-01-01

    In an attempt to produce effective and lower price gaseous Hg(0) adsorbents, two methods of HCl and KMnO4/heat treatment were used respectively for the surface modification of liginite semicoke from inner Mongolia. The different effects of modification process on the surface physical and chemical properties were analyzed. The characteristics and stability of mercury vapor adsorption over two kinds of modified semicoke were investigated. The results indicated that modification process caused lower micropore quantity and volume capacity of semicoke; the C-Cl functional groups, C=O bond and delocalized electron π on the surface of Cl-SC, the amorphous higher valency Mn (x+) , and O=C-OH functional groups on the surface of Mn-H-SC were the active sites for oxidation and adsorption of gaseous Hg(0). Modification process led to higher mercury removal efficiency of semicoke at 140°C and reduced the stability of adsorbed mercury of semicoke in simulated water circumstance simultaneously.

  15. Influence of Pyrolysis Temperature on Rice Husk Char Characteristics and Its Tar Adsorption Capability

    Directory of Open Access Journals (Sweden)

    Anchan Paethanom

    2012-11-01

    Full Text Available A biomass waste, rice husk, was inspected by thermoanalytical investigation to evaluate its capability as an adsorbent medium for tar removal. The pyrolysis process has been applied to the rice husk material at different temperatures 600, 800 and 1000 °C with 20 °C/min heating rate, to investigate two topics: (1 influence of temperature on characterization of rice husk char and; (2 adsorption capability of rice husk char for tar removal. The results showed that subsequent to high temperature pyrolysis, rice husk char became a highly porous material, which was suitable as tar removal adsorbent with the ability to remove tar effectively. In addition, char characteristics and tar removal ability were significantly influenced by the pyrolysis temperature.

  16. [Adsorption Characteristics of Norfloxacin by Biochars Derived from Reed Straw and Municipal Sludge].

    Science.gov (United States)

    Zhang, Han-yu; Wang, Zhao-wei; Gao, Jun-hong; Zhu, Jun-min; Xie, Chao-ran; Xie, Xiao-yun

    2016-02-15

    Two types of biochars were prepared by pyrolyzing reed straw and municipal sludge at the temperature of 500 degrees C. The structure and properties of biochars were characterized by BET, scanning electron microscope (SEM), energy dispersive spectroscopy (EDS) and fourier transform infrared spectroscopy ( FTIR ). The effects of pH value, adsorption time, temperature and initial concentration of norfloxacin (NOR) on the adsorption behaviors were determined by single factor experiments, which were used to preliminarily discuss adsorption mechanism. The results showed that the adsorption of NOR onto biochars derived from reed straw and municipal sludge could reach 70% and 60% of the total adsorption within 12 h, respectively; the maximum adsorption capacities of the two biochars were 2.13 mg x g(-1) (biochar derived from reed straw) and 2.09 mg x g(-1) (biochar derived from municipal sludge). The quantities of both absorptions increased with the decreasing solution pH. The two adsorption kinetics of NOR onto biochars followed the pseudo second order kinetic equations, and adsorption isotherms fitted well with the Langmuir equations. Adsorption thermodynamics parameters such as Gibbs free energy (AG), enthalpy (AH) and entropy (AS) indicated that the two adsorptions were endothermic reactions. Infrared spectroscopy analysis indicated that oxygen-containing functional groups on biochars provided NOR molecules with adsorptive sites, which facilitated the formation of hydrogen bonds between NOR and the biochars.

  17. Characteristics of Nonafluorobutyl Methyl Ether (NFE) Adsorption onto Activated Carbon Fibers and Different-Size-Activated Carbon Particles.

    Science.gov (United States)

    Tanada; Kawasaki; Nakamura; Araki; Tachibana

    2000-08-15

    The characteristics of adsorption of 1,1,1,2,2,3,3,4,4-nonafluorobutyl methyl ether (NFE), a chlorofluorocarbon (CFC) replacement, onto six different activated carbon; preparations (three activated carbon fibers and three different-sized activated carbon particles) were investigated to evaluate the interaction between activated carbon surfaces and NFE. The amount of NFE adsorbed onto the three activated carbon fibers increased with increasing specific surface area and pore volume. The amount of NFE adsorbed onto the three different-sized-activated carbon particles increased with an increase in the particle diameter of the granular activated carbon. The differential heat of the NFE adsorption onto three activated carbon fibers depended on the porosity structure of the activated carbon fibers. The adsorption rate of NFE was also investigated in order to evaluate the efficiency of NFE recovery by the activated carbon surface. The Sameshima equation was used to obtain the isotherms of NFE adsorption onto the activated carbon fibers and different-sized-activated carbon particles. The rate constant k for NFE adsorption onto activated carbon fibers was larger for increased specific surface area and pore volume. The rate of NFE adsorption on activated carbons of three different particle sizes decreased with increasing particle diameter at a low initial pressure. The adsorption isotherms of NFE for the six activated carbons conformed to the Dubinin-Radushkevich equation; the constants BE(0) (the affinity between adsorbate and adsorbent) and W(0) (the adsorption capacity) were calculated. These results indicated that the interaction between the activated carbon and NFE was larger with the smaller specific surface area of the activated carbon fibers and with the smaller particle diameter of the different-sized-activated carbon particles. The degree of packing of NFE in the pores of the activated carbon fibers was greater than that in the pores of the granular activated

  18. Conditions and processes affecting radionuclide transport

    Science.gov (United States)

    Simmons, Ardyth M.; Neymark, Leonid A.

    2012-01-01

    Characteristics of host rocks, secondary minerals, and fluids would affect the transport of radionuclides from a previously proposed repository at Yucca Mountain, Nevada. Minerals in the Yucca Mountain tuffs that are important for retarding radionuclides include clinoptilolite and mordenite (zeolites), clay minerals, and iron and manganese oxides and hydroxides. Water compositions along flow paths beneath Yucca Mountain are controlled by dissolution reactions, silica and calcite precipitation, and ion-exchange reactions. Radionuclide concentrations along flow paths from a repository could be limited by (1) low waste-form dissolution rates, (2) low radionuclide solubility, and (3) radionuclide sorption onto geological media.

  19. Adsorption characteristics of nano-TiO2 onto zebrafish embryos and its impacts on egg hatching.

    Science.gov (United States)

    Shih, Yu-Jen; Su, Chia-Chi; Chen, Chiu-Wen; Dong, Cheng-Di; Liu, Wen-Sheng; Huang, C P

    2016-07-01

    The characteristics of nanoparticles (NPs) uptake may fundamentally alter physicochemical effects of engineered NPs on aquatic organisms, thereby yielding different ecotoxicology assessment results. The adsorption behavior of nano-TiO2 (P-25) on zebrafish embryos in Holtfreter's medium (pH 7.2, I ∼ 7.2 × 10(-2) M) and the presence of sodium alginate (100 mg/L) as dispersant was investigated. Zebrafish embryos (total 100) were exposed to nano-TiO2 at different concentrations (e.g., 0, 10, 20, 60, 120 mg/L) in batch-mode assay. The adsorption capacity of nano-TiO2 on fish eggs was determined by measuring the Ti concentration on the egg surface using ICP-OES analysis. Results showed that the adsorption capacity increased rapidly in the first hour, and then declined to reach equilibrium in 8 h. The adsorption characteristics was visualized as a three-step process of rapid initial layer formation, followed by break-up of aggregates and finally rearrangement of floc structures; the maximum adsorption capacity was the sum of an inner rigid layers of aggregates of 0.81-0.84 μg-TiO2/#-egg and an outer softly flocculated layers of 1.01 μg-TiO2/#-egg. The Gibbs free energy was 543.29-551.26 and 100.75 kJ/mol, respectively, for the inner-layer and the outer-layer aggregates. Adsorption capacity at 0.5-1.0 μg-TiO2/#-egg promoted egg hatching; but hatching was inhibited at higher adsorption capacity. Results clearly showed that the configuration of TiO2 aggregates could impact the hatching efficiency of zebrafish embryos.

  20. Moisture adsorption desorption characteristics of stainless steel tubing measured by ball surface acoustic wave trace moisture analyzer

    Science.gov (United States)

    Tsuji, Toshishiro; Akao, Shingo; Oizumi, Toru; Takeda, Nobuo; Tsukahara, Yusuke; Yamanaka, Kazushi

    2017-07-01

    A ball surface acoustic wave (SAW) trace moisture analyzer (TMA) was applied to measuring the adsorption and desorption (AD) characteristics of a stainless steel tube. For the first time, two-frequency measurement for precise temperature compensation was attempted at intervals of 3 s using a burst waveform undersampling circuit. We succeeded in measuring the variations of moisture transit time and dry-down dynamics caused by inner surface treatments such as bright annealing (BA), electropolishing (EP), and electrochemical buffing (ECB) using a sample-tube length of only 100 mm at a flow rate of 0.1 L/min. Net moisture adsorption was evaluated from the measured adsorption subtracted by the background adsorption. As a result, it was found that the adsorption on the ECB tube was smaller than those on EP and BA tubes by 1/3 and 1/4, respectively, at a baseline concentration of 13 ppbv. From these results, it was demonstrated that the ball SAW TMA could be used for measuring the AD characteristics of stainless steel tubes with various surface treatments.

  1. Development of experimental setup for study of adsorption characteristics of porous materials down to 4.2 K

    Science.gov (United States)

    Behera, Upendra; Kasthurirengan, Srinivasan; Krishnamoorthy, V.; Senthil Kumar, A.; Kuzhiveli, Biju T.; Gangradey, Ranjana

    2012-06-01

    The knowledge of adsorption characteristics of activated carbon (porous material) in the temperature range from 5 to 20 K is essential when used in cryosorption pumps for nuclear fusion applications. However, such experimental data are very scarce in the literature, especially below 77 K. So, an experimental system is designed and fabricated to measure the adsorption characteristics of porous materials under variable cryogenic temperatures (from 5 K to 100 K). This is based on the commercially available micropore-analyser coupled to a closed helium cycle two-stage Gifford McMahon (GM) Cryocooler, which allows the sample to be cooled to 4.2 K. The sample port is coupled to the Cryocooler through a heat switch, which isolates this port from the cold head of the Cryocooler. By this, the sample temperature can now be varied without affecting the Cryocooler. The setup enables adsorption studies in the pressure range from atmospheric down to 10-4 Pa. The paper describes the details of the experimental setup and presents the results of adsorption studies at 77 K for activated carbon with nitrogen as adsorbate. The system integration is now completed to enable adsorption studies at 4.2 K.

  2. Influence of Coal Particle Size on Coal Adsorption and Desorption Characteristics

    Science.gov (United States)

    Zhang, Lei; Aziz, Naj; Ren, Ting; Nemcik, Jan; Tu, Shihao

    2014-10-01

    Accurate testing coal isotherm can play a significant role in the areas of coal seam gas drainage, outburst control, CO2 geo-sequestration, coalbed methane (CBM) and enhanced coalbed methane recovery (ECBM) etc. The effect of particle size on the CO2 and CH4 sorption capacity of bituminous coal from Illawarra, Australia was investigated at 35°C and at pressure up to 4 MPa. A unique indirect gravimetric apparatus was used to measure the gas adsorption and desorption isotherms of coal of different particle sizes ranging from around 150 urn to 16 mm. Langmuir model was used to analysis the experimental results of all gases. Coal particle size was found to have an apparent effect on the coal ash content and helium density results. Coal with larger particle size had higher ash content and higher helium density. The sorption isotherm was found to be highly sensitive with helium density of coal which was determined in the procedure of testing the void volume of sample cell. Hence, coal particle size had a significant influence on the coal sorption characteristics including sorption capacity and desorption hysteresis for CO2 and CH4, especially calculated with dry basis of coal. In this study, the 150-212 um (150 um) coal samples achieved higher sorption capacity and followed by 2.36-3.35 mm (2.4 mm), 8-9.5 mm (8 mm) and 16-19 mm (16 mm) particle size samples. However, the differences between different coal particles were getting smaller when the sorption isotherms are calculated with dry ash free basis. Test with 150 um coal samples were also found to have relatively smaller desorption hysteresis compared with the other larger particle size samples. The different results including adsorption/desorption isotherm, Langmuir parameters and coal hysteresis were all analysed with the CO2 and CH4 gases.

  3. Adsorption characteristics of a cationic porphyrin on nanoclay at various pH.

    Science.gov (United States)

    Rice, Zachary; Bergkvist, Magnus

    2009-07-15

    Natural and synthetic porphyrin derivatives offer a range of applications including enzymatic catalysis, photosensitizers for light harvesting and chemical reactions, and molecular electronics. They exhibit unique optical spectra dominated by the presence of Soret and Q-band structures whose position and shape offer a straightforward method to characterize porphyrins in various surroundings. In many applications it is often beneficial to have porphyrins adsorbed onto a solid matrix. Applications of porphyrin-clay complexes extend to numerous biological applications including pharmaceutical drug delivery, cosmetics, and agricultural applications and thus a full understanding of porphyrin-clay surface interactions are essential. Here we investigated the adsorption behavior of meso-tetra(4-N,N,N-trimethylanilinium) porphine (TMAP) onto sodium containing, natural montmorillonite clay (Cloisite Na(+)) in characteristic biological buffers over a range of pHs (approximately 2-9). Spectroscopic analyses show a linear absorption response at acidic and basic pHs but a slight deviation at intermediate pHs. Absorption spectra for TMAP on clay showed distinct red shifts of the Soret and Q-bands compared to free TMAP for all buffer conditions indicating core pi-electron delocalization into the substituent rings. At intermediate pHs, a gradual transition between protonated/deprotonated states were seen, presumably due to higher H(+) concentration at the surface than in bulk. Results indicate TMAP adsorption to clay occurs in a monolayer fashion at low/high pH while slightly acidic/neutral pH possibly rearrange on the surface and/or form aggregates. AFM images of clay saturated with TMAP are reported and show single isolated clay sheets without aggregation, similar to clay without TMAP.

  4. Adsorption Characteristics of Pb(2+) onto Wine Lees-Derived Biochar.

    Science.gov (United States)

    Zhu, Qihong; Wu, Jun; Wang, Lilin; Yang, Gang; Zhang, Xiaohong

    2016-08-01

    Biochar has great advantages in soil amendment and polluted soil remediation. Herein, the pore and adsorption properties of wine lees-derived biochar were explored. Specifically, the adsorption isotherm and kinetics of Pb(2+) onto wine lees-derived biochar were examined. Experimental results revealed that wine lees-derived biochar featured large specific surface area and total pore volume, and high contents of -COOH and -OH on its surface. Adsorption of Pb(2+) onto wine lees-derived biochar proceeded via a multilayer adsorption mechanism, as described by the Freundlich adsorption model. Adsorption kinetics followed the Lagergren pseudo-second-order kinetics model; adsorption equilibrium was achieved within 30-60 min. Furthermore, the effect of solution pH on the adsorption of Pb(2+) was investigated. Within the studied pH range of 3-6, the adsorption capacity increased with increasing pH. Under established optimized conditions, wine lees-derived biochar achieved a Pb(2+) adsorption capacity of 79.12 mg/g.

  5. Adsorption characteristics of thorium on silica-based anion exchange resins

    Institute of Scientific and Technical Information of China (English)

    陈彦良; 赵龙; 韦悦周; 何林锋; 唐方东

    2015-01-01

    To isolate and separate thorium from nitric acid solutions, three silica-based anion exchange resins were synthesized. Batch experiments were carried out to investigate adsorption behavior of thorium in nitric acid solutions. Adsorption at different concentrations of nitric acid and thorium, influence of contact time and coex-isting metal ions, and effect of NO–3 were investigated in detail. It was found that at high HNO3 concentrations, the resins exhibited higher adsorption capacity and better affinity towards thorium. The adsorption kinetics could be described by the pseudo-second order model equation, while the adsorption isotherms were well cor-related by the Langmuir model. The maximum capacity towards thorium species on SiPyR-N4 was evaluated at 27–28 mg/g-resin. The thermodynamic parameters indicated the adsorption was an exothermic reaction. The presence of NO–3 was found to promote the retention of the thorium species.

  6. Adsorption capacities of activated carbons for geosmin and 2-methylisoborneol vary with activated carbon particle size: Effects of adsorbent and adsorbate characteristics.

    Science.gov (United States)

    Matsui, Yoshihiko; Nakao, Soichi; Sakamoto, Asuka; Taniguchi, Takuma; Pan, Long; Matsushita, Taku; Shirasaki, Nobutaka

    2015-11-15

    The adsorption capacities of nine activated carbons for geosmin and 2-methylisoborneol (MIB) were evaluated. For some carbons, adsorption capacity substantially increased when carbon particle diameter was decreased from a few tens of micrometers to a few micrometers, whereas for other carbons, the increase of adsorption capacity was small for MIB and moderate for geosmin. An increase of adsorption capacity was observed for other hydrophobic adsorbates besides geosmin and MIB, but not for hydrophilic adsorbates. The parameter values of a shell adsorption model describing the increase of adsorption capacity were negatively correlated with the oxygen content of the carbon among other characteristics. Low oxygen content indicated low hydrophilicity. The increase of adsorption capacity was related to the hydrophobic properties of both adsorbates and activated carbons. For adsorptive removal of hydrophobic micropollutants such as geosmin, it is therefore recommended that less-hydrophilic activated carbons, such as coconut-shell-based carbons, be microground to a particle diameter of a few micrometers to enhance their equilibrium adsorption capacity. In contrast, adsorption by hydrophilic carbons or adsorption of hydrophilic adsorbates occur in the inner pores, and therefore adsorption capacity is unchanged by particle size reduction.

  7. Studies on Thorium Adsorption Characteristics upon Activated Titanium Hydroxide Prepared from Rosetta Ilmenite Concentrate

    Energy Technology Data Exchange (ETDEWEB)

    Gado, M, E-mail: parq28@yahoo.com; Zaki, S [Nuclear Materials Authority, P. O. Box 530 El Maadi, Cairo (Egypt)

    2016-01-01

    The titanium hydroxide prepared from Rosetta ilmenite concentrate has been applied for Th (IV) adsorption from its acid aqueous solutions. The prepared hydroxide is first characterized by both Fourier transform infrared (FT-IR) spectrum and thermogravimetric analysis. The relevant factors affecting the adsorption process have been studied. The obtained equilibrium data fits well with the Langmuir isotherm rather than Freundlich isotherm, while the adsorption kinetic data follow the pseudo-second order model. The different thermodynamic parameters have also been calculated and indicate that the adsorption process is spontaneous.

  8. [Adsorption Characteristics of Nitrate and Phosphate from Aqueous Solution on Zirconium-Hexadecyltrimethylammonium Chloride Modified Activated Carbon].

    Science.gov (United States)

    Zheng, Wen-jing; Lin, Jian-wei; Zhan, Yan-hui; Wang, Hong

    2015-06-01

    A novel adsorbent material, i.e., zirconium-cationic surfactant modified activated carbon (ZrSMAC) was prepared by loading zirconium hydroxide and hexadecyltrimethylammonium chloride (CTAC) on activated carbon, and was used as an adsorbent for nitrate and phosphate removal from aqueous solution. The adsorption characteristics of nitrate and phosphate on ZrSMAC from aqueous solution were investigated in batch mode. Results showed that the ZrSMAC was effective for nitrate and phosphate removal from aqueous solution. The pseudo-second-order kinetic model fitted both the nitrate and phosphate kinetic experimental data well. The equilibrium isotherm data of nitrate adsorption onto the ZrSMAC were well fitted to the Langmuir, Dubinin-Radushkevich (D-R) and Freundlich isotherm models. The equilibrium isotherm data of phosphate adsorption onto the ZrSMAC could be described by the Langmuir and,D- R isotherm models. According to the Langmuir isotherm model, the maximum nitrate and phosphate adsorption capacities for the ZrSMAC were 7.58 mg x g(-1) and 10.9 mg x g(-1), respectively. High pH value was unfavorable for nitrate and phosphate adsorption onto the ZrSMAC. The presence of Cl-, HCO3- and SO4(2-) in solution reduced the nitrate and phosphate adsorption capacities for the ZrSMAC. The nitrate adsorption capacity for the ZrSMAC was reduced by the presence of coexisting phosphate in solution, and the phosphate adsorption capacity for the ZrSMAC was also reduced by the presence of coexisting nitrate in solution. About 90% of nitrate adsorbed on the ZrSMAC could be desorbed in 1 mol x L(-1) NaCl solution, and about 78% of phosphate adsorbed on the ZrSMAC could be desorbed in 1 mol x L(-1) NaOH solution. The adsorption mechanism of nitrate on the ZrSMAC included the anion exchange interactions and electrostatic attraction, and the adsorption mechanism of phosphate on the ZrSMAC included the ligand exchange interaction, electrostatic attraction and anion exchange interaction.

  9. Experimental study on the effects of sediment size and porosity on contaminant adsorption/desorption and interfacial diffusion characteristics

    Institute of Scientific and Technical Information of China (English)

    FAN Jing-yu; HE Xiao-yan; WANG Dao-zeng

    2013-01-01

    The joint effects of the sediment size and porosity on the contaminant adsorption/desorption and interracial diffusion characteristics were experimentally investigated.The adsorption of Phosphorus (P) on the natural and artificial sediment suspensions was measured with respect to the P adsorption isotherms and kinetics in the experiment.The obtained adsorption isotherms for different grain-sized sediment suspensions fit well with the Langmuir equation,dependent on the initial aqueous concentration and sediment content.The P kinetic adsorption behaviors for cohesive fine-grained and non-cohesive coarse-grained sediment suspensions clearly show the size-dependent feature.On the other hand,the P kinetic release feature of a porous sediment layer is affected by not only the direct desorption of the uppermost sediments,but also the diffusivity in the pore-water within the underlying sediment layer,characterized by the sediment size and porosity,respectively.Furthermore,the temporal contaminant release from the permeable sediment layer into the overlying water colunm increases with the increasing flow velocity,while this enhancement in mediating the interfacial diffusion flux is somewhat insignificant in an immediate release stage,largely due to the resistance of the diffusive boundary layer on the hydrodynamic disturbance.

  10. STUDY ON THE PROPERTIES OF DIFFERENT ACTIVATED CARBON FIBERS AND THEIR ADSORPTION CHARACTERISTICS FOR FORMALDEHYDE

    Institute of Scientific and Technical Information of China (English)

    H.Q. Rong; Z.Y. Ryu; J.T. Zheng

    2001-01-01

    Porous structure and surface chemistry of activated carbon fibers obtained by differ-ent precursors and activation methods were investigated. Adsorption isotherms werecharacterized by nitrogen adsorption at 77K over a relative pressure range from 10 6to 1. The regularization method according to Density Functional Theory (DFT) wasemployed to calculate the pore size distribution in the samples. Their specific surfaceareas were calculated by BET method, micropore volume and microporous specificsurface area calculated by t-plot method and MPD by Horvath-Kawazoe equation. Mi-cropore volume of rayon-based ACF was higher than that of other samples. The staticand dynamic adsorption capacity for formaldehyde on different ACFs was determined.The results show that steam activated Rayon-based A CFs had higher adsorption capac-ity than that of steam and KOH activated PAN-A CFs. Breakthrough curves illustratedthat Rayon-ACFs had longer breakthrough time, thus they possessed higher adsorp-tion capacity for formaldehyde than that of PAN-ACFs. The entire sample had smalladsorption capacity and short breakthrough time for water. Rayon-A CFs had exccl-lent adsorption selectivity for formaldehyde than PAN-ACFs. And the samples withhigh surface areas had relatively high adsorption capacity for formaldehyde. Elementaicontent of different A CFs were performed. Rayon-based A CFs contained more oxygenthan PAN-ACFs, which may be attributed to their excellent adsorption capacity forformaldehyde.

  11. Characteristics of an activated carbon monolith for a helium adsorption compressor

    NARCIS (Netherlands)

    Lozano-Castello, D.; Jorda-Beneyto, M.; Cazorla-Amoros, D.; Linares-Solano, A.; Burger, J.F.; Brake, ter H.J.M.; Holland, H.J.

    2010-01-01

    An activated carbon monolith (ACM) with a high helium adsorption/desorption capacity, high density, low pressure drop, low thermal expansion and good mechanical properties was prepared and applied successfully in a helium adsorption compressor as a part of a 4.5 K sorption cooler. The activated carb

  12. Isotherm, Kinetic and Thermodynamic Characteristics for Adsorption of Congo Red by Activated Carbon

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jong Jib [Kongju National University, Cheonan (Korea, Republic of)

    2015-02-15

    Batch experiment studies were carried out for adsorption of congo red using granular activated carbon with various parameters such as activated carbon dose, pH, initial dye concentration, temperature and contact time. Equilibrium experimental data are fitted to the Langmuir, Freundlich, Temkin and Dubin-Radushkevich isotherm equations. From Freundlich's separation factor (1/n) estimated, adsorption could be employed as effective treatment method for adsorption of congo red from aqueous solution. Base on Temkin constant (B) and Dubinin-Radushkevich constant (E), this adsorption process is physical adsorption. Adsorption kinetics has been tested using pseudo-first order and pseudo second order models. The results followed pseudo second order model with good correlation. Adsorption process of congo red on granular activated carbon was endothermic (ΔH=42.036 kJ/mol) and was accompanied by decrease in Gibbs free energy (ΔG=-2.414 to -4.596 kJ/mol) with increasing adsorption temperature.

  13. The surface characteristics of hyperbranched polyamide modified corncob and its adsorption property for Cr(VI)

    Science.gov (United States)

    Lin, Hai; Han, Shaoke; Dong, Yingbo; He, Yinhai

    2017-08-01

    A low-cost anion adsorbent for Cr(VI) effectively removing was synthesized by hyperbranched polyamide modified corncob (HPMC). Samples were characterized by Brunauer-Emmett-Teller (BET) surface area analysis, field-emission scanning electron microscopy (FE-SEM) with energy-dispersive X-ray spectroscopy, Fourier transform infrared (FTIR) and zeta potential analysis. Kinetics, isotherms and thermodynamics studies of HPMC for Cr(VI) adsorption were investigated in batch static experiments, in the temperature range of 25-45 °C, pH = 2.0. Results showed that the adsorption was rapid and stable, with the uptake capacity higher than 80% after 30 min. Adsorption behavior and rate-controlling mechanisms were analyzed using three kinetic models (pseudo-first order, pseudo-second order, intra-particle kinetic model). Kinetic studies showed that the adsorption of HPMC to Cr(VI) relied the pseudo-second-order model, and controlled both by the intra-particle diffusion and film diffusion. Equilibrium data was tested by Langmuir and Freundlich adsorption isotherm models. Langmuir model was more suitable to indicate a homogeneous distribution of active sites on HPMC and monolayer adsorption. The maximum adsorption capacity from the Langmuir model, qmax, was 131.6 mg/g at pH 2.0 and 45 °C for HPMC. Thermodynamic parameters revealed spontaneous and endothermic nature of the Cr(VI) adsorption onto HPMC.

  14. Ab initio Investigation of Adsorption Characteristics of Bisphosphonates on Hydroxyapatite (001) Surface

    CERN Document Server

    Ri, Mun-Hyok; Yu, Chol-Jun; Kim, Song-Un

    2016-01-01

    The structures of some bisphosphonates (clodronate, etidronate, pamidronate, alendronate, risedronate, zoledronate, minodronate) were obtained and analyzed, and their adsorption energies onto hydroxyapatite (001) surface were compared to find out ranking order of binding affinity, which shows that the adsorption energy is the largest for pamidronate, followed by alendronate, zoledronate, clodronate, ibandronate, the lowest for minodronate and etidronate.

  15. Adsorption characteristics of construction waste for heavy metals from urban stormwater runoff☆

    Institute of Scientific and Technical Information of China (English)

    Jianlong Wang; Pingping Zhang; Liqiong Yang; Tao Huang

    2015-01-01

    Stormwater runoff has become an important source of surface water pollution. Bioretention, a low impact devel-opment measure in urban stormwater management, has been proven to be effective in the removal of pol utants from stormwater runoff, with appropriate bioretention media. In this study, construction wastes were selected as bioretention media to remove heavy metals from stormwater runoff. Static and dynamic adsorption batch exper-iments were carried out to investigate the adsorption of heavy metals in simulated stormwater runoff system with construction wastes in different particle sizes. The experimental results show that the pseudo-second-order kinetic model characterizes the adsorption process and the adsorption equilibrium data are wel described by Freundlich isotherm model. The construction wastes used can remove heavy metals from stormwater runoff effectively, with their average removal rates al more than 90%. The particle size of construction wastes greatly influences the equilibrium time, rate and adsorption capacity for heavy metals.

  16. Characteristics of PAHs adsorption on inorganic particles and activated sludge in domestic wastewater treatment.

    Science.gov (United States)

    Liu, J J; Wang, X C; Fan, B

    2011-05-01

    The occurrence of polycyclic aromatic hydrocarbons (PAHs) in a domestic wastewater treatment plant (WWTP) was investigated in a 1 year period. In order to understand how PAHs were removed at different stages of the treatment process, adsorption experiments were conducted using quartz sand, kaolinite, and natural clay as inorganic adsorbents and activated sludge as organic adsorbent for adsorbing naphthalene, phenanthrene, and pyrene. As a result, the adsorption of PAHs by the inorganic adsorbents well followed the Langmuir isotherm while that by the activated sludge well followed the Freundlich isotherm. By bridging equilibrium partitioning coefficient with the parameters of adsorption isotherm, a set of mathematical models were developed. Under an assumption that in the primary settler PAHs removal was by adsorption onto inorganic particles and in the biological treatment unit it was by adsorption onto activated sludge, the model calculation results fairly reflected the practical condition in the WWTP.

  17. Zinc adsorption and desorption characteristics in root cell wall involving zinc hyperaccumulation in Sedum alfredii Hance.

    Science.gov (United States)

    Li, Ting-qiang; Yang, Xiao-e; Meng, Fan-hua; Lu, Ling-li

    2007-02-01

    Radiotracer techniques were employed to characterize (65)Zn adsorption and desorption in root-cell-wall of hyperaccumulating ecotype (HE) and non-hyperaccumulating ecotype (NHE) species of Sedum alfredii Hance. The results indicated that at the end of a 30 min short time radioisotope loading period, comparable amounts of (65)Zn were accumulated in the roots of the two ecotypes Sedum alfredii, whereas 2.1-fold more (65)Zn remains in NHE root after 45-min desorption. At the end of 60 min uptake period, no difference of (65)Zn accumulation was observed in undesorbed root-cell-wall of Sedum alfredii. However, 3.0-fold more (65)Zn accumulated in desorbed root-cell-wall of NHE. Zn(2+) binding in root-cell-wall preparations of NHE was greater than that in HE under high Zn(2+) concentration. All these results suggested that root-cell-wall of the two ecotypes Sedum alfredii had the same ability to adsorb Zn(2+), whereas the desorption characteristics were different, and with most of (65)Zn binding on root of HE being available for loading into the xylem, as a result, more (65)Zn was translocated to the shoot.

  18. Phosphate Adsorption and Surface Charge Characteristics and Their Relations to Mineralogy of Some Soils from outhern China

    Institute of Scientific and Technical Information of China (English)

    ZHANGMINGKUI; M.J.WILSON; 等

    1998-01-01

    The phosphate adsorption and srface charge characteristics of the tropical and subtropical soils derived from diferent parent materials in China were determined,and their relations to soil mineralogy were analysed.The results showed that all soil phosphate adsorption curves were well fitted by Freundlich equation and Langmuir equation.The maximum buffering capacity of P ranged from 66 to 9880 mg kg-1 ,with an increasing order of purple soil,skeletal soil,red soil.lateritic red soil,yellow soil and latosol;and the highest value was 149 times the lowest value,which indicated great differences among these soils in phosphate adsorption and supplying characteristics The pH0(zero point of charge) values obtained by salt titration-potential titration varied from 3.03 to 5.49,and the highest value was found in the laosol derived from basalt whereas the lowest value was found in the purple soil.The correlation analysis indicated the the mian minerals responible for hpospate adsorption in the soils were gibbsite,amophous iron oxide and kaolinite;and the pH0 was mainly controlled by kaolinite,gibbsited an oxides.

  19. Effects of textural and surface characteristics of microporous activated carbons on the methane adsorption capacity at high pressures

    Energy Technology Data Exchange (ETDEWEB)

    Bastos-Neto, M. [Grupo de Pesquisas em Separacoes por Adsorcao (GPSA), Departamento de Engenharia Quimica, Universidade Federal do Ceara, Campus Universitario do Pici, Bl 709 60455-760 Fortaleza, CE (Brazil); Canabrava, D.V. [Grupo de Pesquisas em Separacoes por Adsorcao (GPSA), Departamento de Engenharia Quimica, Universidade Federal do Ceara, Campus Universitario do Pici, Bl 709 60455-760 Fortaleza, CE (Brazil); Torres, A.E.B. [Grupo de Pesquisas em Separacoes por Adsorcao (GPSA), Departamento de Engenharia Quimica, Universidade Federal do Ceara, Campus Universitario do Pici, Bl 709 60455-760 Fortaleza, CE (Brazil); Rodriguez-Castellon, E. [Departamento de Quimica Inorganica, Cristalografia y Mineralogia (Unidad Asociada al ICP-CSIC), Facultad de Ciencias, Universidad de Malaga, 29071 Malaga (Spain); Jimenez-Lopez, A. [Departamento de Quimica Inorganica, Cristalografia y Mineralogia (Unidad Asociada al ICP-CSIC), Facultad de Ciencias, Universidad de Malaga, 29071 Malaga (Spain); Azevedo, D.C.S. [Grupo de Pesquisas em Separacoes por Adsorcao (GPSA), Departamento de Engenharia Quimica, Universidade Federal do Ceara, Campus Universitario do Pici, Bl 709 60455-760 Fortaleza, CE (Brazil)]. E-mail: diana@gpsa.ufc.br; Cavalcante, C.L. [Grupo de Pesquisas em Separacoes por Adsorcao (GPSA), Departamento de Engenharia Quimica, Universidade Federal do Ceara, Campus Universitario do Pici, Bl 709 60455-760 Fortaleza, CE (Brazil)

    2007-04-30

    The objective of this study is to relate textural and surface characteristics of selected microporous activated carbons to their methane storage capacity. In this work, a magnetic suspension balance (Rubotherm, Germany) was used to measure methane adsorption isotherms of several activated carbon samples. Textural characteristics were assessed by nitrogen adsorption on a regular surface area analyzer (Autosorb-MP, by Quantachrome, USA). N{sub 2} adsorption was analysed by conventional models (BET, DR, HK) and by Monte Carlo molecular simulations. Elemental and surface analyses were performed by X-ray photoelectronic spectroscopy (XPS) for the selected samples. A comparative analysis was then carried out with the purpose of defining some correlation among the variables under study. For the system under study, pore size distribution and micropore volume seem to be a determining factor as long as the solid surface is perfectly hydrophobic. It was concluded that the textural parameters per se do not unequivocally determine natural gas storage capacities. Surface chemistry and methane adsorption equilibria must be taken into account in the decision-making process of choosing an adsorbent for gas storage.

  20. Adsorption characteristics of an enteric virus-binding protein to norovirus, rotavirus and poliovirus

    Directory of Open Access Journals (Sweden)

    Imai Takahiro

    2011-12-01

    Full Text Available Abstract Background Water contamination with human enteric viruses has posed human health risks all over the world. Reasonable and facile methodologies for recovering and quantifying infectious enteric viruses in environmental samples are needed to address the issues of waterborne viral infectious diseases. In this study, a bacterial protein that has a binding capability with several enteric viruses is discovered, and its binding characteristics were investigated for utilizing it as a viral adsorbent in virus recovery and detection technologies. Results A gene of an enteric virus-binding protein (EVBP, derived from a monomer of a bacterial chaperon protein GroEL, was successfully acquired from a genomic DNA library of activated sludge microorganisms with nested PCR. Equilibrium dissociation constants between EVBP and norovirus-like particles (NoVLPs of genotypes GI.7 and GII.4, estimated with quartz crystal microbalance method, were 240 and 210 nM, respectively. These values of equilibrium dissociation constant imply that the binding affinity between EVBP and NoVLPs is 1 to 3-log weaker than that in general antigen-antibody interactions, but about 2-log stronger than that in weak specific interactions of proteins with cations and organic polymers. The adsorptions of EVBP to norovirus, group A rotavirus and poliovirus type 1 were found to be significant in enzyme-linked immunosorbent assay. Meanwhile, the binding of native GroEL tetradecamer to viral particles was weaker than that of EVBP, presumably because of a steric hindrance. The small molecule of EVBP could have an advantage in the access to the surface of viral particles with rugged structure. Conclusions EVBP that has a broad binding spectrum to enteric viruses was newly discovered. The broad binding characteristic of EVBP would allow us to utilize it as a novel adsorbent for detecting diverse enteric viruses in clinical and environmental samples.

  1. [Surface characteristics of alkali modified activated carbon and the adsorption capacity of methane].

    Science.gov (United States)

    Zhang, Meng-Zhu; Li, Lin; Liu, Jun-Xin; Sun, Yong-Jun; Li, Guo-Bin

    2013-01-01

    Coconut shell based activated carbon was modified by alkali with different concentrations. The surface structures of tested carbons were observed and analyzed by SEM and BET methods. Boehm's titration and SEM/EDS methods were applied to assay the functional groups and elements on the carbon surface. The adsorption of methane on tested carbons was investigated and adsorption behavior was described by the adsorption isotherms. Results showed that surface area and pore volume of modified carbon increased and surface oxygen groups decreased as the concentration of the alkali used increased, with no obvious change in pore size. When concentration of alkali was higher than 3.3 mol x L(-1), the specific surface area and pore volume of modified carbon was larger than that of original carbon. Methane adsorption capacity of alkali modified carbon increased 24%. Enlargement of surface area and pore volume, reduction of surface oxygen groups will benefit to enhance the methane adsorption ability on activated carbon. Adsorption behavior of methane followed the Langmuir isotherm and the adsorption coefficient was 163.7 m3 x mg(-1).

  2. Adsorption and desorption characteristics of crystal violet in bottom ash column

    Directory of Open Access Journals (Sweden)

    Puthiya Veetil Nidheesh

    2012-06-01

    Full Text Available This study described adsorption of Crystal Violet (CV by bottom ash in fixed-bed column mode. Equilibrium of adsorption was studied in batch mode for finding adsorption capacity of bottom ash. In fixed bed column adsorption, the effects of bed height, feed flow rate, and initial concentration were studied by assessing breakthrough curve. The slope of the breakthrough curve decreased with increasing bed height. The breakthrough time and exhaustion time were decreased with increasing influent CV concentration and flow rates. The effect of bed depth, flow rate and CV concentration on the adsorption column design parameters were analyzed. Bed depth service time (BDST model was applied for analysis of crystal violet adsorption in the column. The adsorption capacity of bottom ash was calculated at 10% breakthrough point for different flow rates and concentrations. Desorption studies reveals that recovery of CV from bottom ash was effective by using CH3COOH than H2SO4, NaOH, HCl and NaCl solutions.

  3. ADSORPTION AND DESORPTION CHARACTERISTICS OF CRYSTAL VIOLET IN BOTTOM ASH COLUMN

    Directory of Open Access Journals (Sweden)

    Puthiya Veetil Nidheesh

    2012-01-01

    Full Text Available This study described adsorption of Crystal Violet (CV by bottom ash in fixed-bed column mode. Equilibrium of adsorption was studied in batch mode for finding adsorption capacity of bottom ash. In fixed bed column adsorption, the effects of bed height, feed flow rate, and initial concentration were studied by assessing breakthrough curve. The slope of the breakthrough curve decreased with increasing bed height. The breakthrough time and exhaustion time were decreased with increasing influent CV concentration and flow rates. The effect of bed depth, flow rate and CV concentration on the adsorption column design parameters were analyzed. Bed depth service time (BDST model was applied for analysis of crystal violet adsorption in the column. The adsorption capacity of bottom ash was calculated at 10% breakthrough point for different flow rates and concentrations. Desorption studies reveals that recovery of CV from bottom ash was effective by using CH3COOH than H2SO4, NaOH, HCl and NaCl solutions.

  4. Adsorption characteristics of diclofenac and sulfamethoxazole to graphene oxide in aqueous solution.

    Science.gov (United States)

    Nam, Seung-Woo; Jung, Chanil; Li, Hang; Yu, Miao; Flora, Joseph R V; Boateng, Linkel K; Her, Namguk; Zoh, Kyung-Duk; Yoon, Yeomin

    2015-10-01

    The adsorptive properties of graphene oxide (GO) were characterized, and the binding energies of diclofenac (DCF) and sulfamethoxazole (SMX) on GO adsorption were predicted using molecular modeling. The adsorption behaviors of DCF and SMX were investigated in terms of GO dosage, contact time, and pH. Additionally, the effects of sonication on GO adsorption were examined. GO adsorption involves "oxygen-containing functional groups" (OCFGs) such as COOH, which exhibit negative charges over a wide range of pH values (pH 3-11). DCF (-18.8 kcal mol(-1)) had a more favorable binding energy on the GO surface than SMX (-15.9 kcal mol(-1)). Both DCF and SMX were removed from solution (adsorbed to GO), up to 35% and 12%, respectively, within 6h, and an increase in GO dosage enhanced the removal of DCF. Electrostatic repulsion occurred between dissociated DCF/SMX and the more negatively charged GO at basic pH (>pKa). The sonication of GO significantly improved the removal of DCF (75%) and SMX (30%) due to dispersion of exfoliated GO particles and the reduction of OCFGs on the GO surface. Both DCF and SMX in the adsorption isotherm were explained well by the Freundlich model. The results of this study can be used to maximize the adsorption capacities of micropollutants using GO in water treatment processes.

  5. Adsorption characteristics of Orange II and Chrysophenine on sludge adsorbent and activated carbon fibers.

    Science.gov (United States)

    Hsiu-Mei, Chiang; Ting-Chien, Chen; San-De, Pan; Chiang, Hung-Lung

    2009-01-30

    Sludge adsorbent (SA) and commercial activated carbon fibers (ACFC and ACFT) were applied to Orange II and Chrysophenine (CH) adsorption (BET surface area: ACFC>ACFT>SA). ACFT was primarily in the micropore range, while SA was approximately 500 A (macropore) and 80 A (mesopore). The ACFC pore volume was high in both the mesopore and micropore regions. Measurement of the oxygen surface functional groups of the adsorbents using Boehm's titration method showed a similar distribution on the carbon fibers (mainly in the carbonyl group), while SA was mainly in the carboxyl, lactone and phenolic groups. The SA, ACFC and ACFT adsorption capacities of Orange II (30-80 mg/l) ranged from 83 to 270, 209-438, and 25-185 mg/g at temperatures ranging from 10 to 60 degrees C, respectively. CH concentration ranged from 30 to 80 mg/l, corresponding to SA and ACFC adsorption capacities of 39-191 and 48-374 mg/g over the defined temperature range, from 10 to 60 degrees C. CH adsorption on ACFT was low. The adsorption capacity of Orange II on ACFT was lower than on SA at 10 degrees C, but at higher temperatures the Orange II molecules were transported into the ACFT, producing an adsorption capacity similar to that of SA. Mass transfer increased with temperature, overcoming the adsorption energy barrier. Overall, SA and ACFC were more effective than ACFT.

  6. Surface characteristics of modified carbon nanotubes and its application in lead adsorption from aqueous solution

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Carbon nanotubes (CNT) were modified by nitric acid oxidation. Infrared spectroscopy (IR) demonstrated that hydroxyl (-OH) and carbonyl (-C== O) functional groups were introduced to the surface of modified CNT. Micrometrics ASAP 2000 measurement showed that the surface area of modified CNT was slightly increased. Furthermore, the Pb2+ adsorption behavior on the surface of modified CNT has been investigated. The results indicate that the modified CNT has an exceptional adsorption capability for Pb2+ removal. The adsorption isotherms are well described by the Langmuir equation under test temperatures and the kinetics level is three.

  7. Adsorption Characteristics of Macroporous Resin for Oil Removal from Desulphurization Wastewater on Board

    Science.gov (United States)

    Li, Tie; Chen, Chen; Jin, Qi; Zhao, Jiao; Tang, Xiaojia; Zhu, Yimin

    2017-01-01

    According to our previous results on the magnesium-based exhaust gas cleaning system (Mg-EGCS), PAHs and total oil content were the main factors affecting the COD in the wastewater. In this work, three kinds of adsorption materials were investigated and macroporous resin was selected for oil removal. The effects of the dosage of macroporous resin, adsorption time and the flow rate were studied, and thermodynamics equation was used to characterize the adsorption process. The results showed that macroporous resin is a good candidate for oil removal from desulphurization wastewater on board, and the COD after treatment can meet the discharge criteria set by the International Maritime Organization (IMO).

  8. [Preparation of porous ceramics based on waste ceramics and its Ni2+ adsorption characteristics].

    Science.gov (United States)

    Zhang, Yong-Li; Wang, Cheng-Zhi; Shi, Ce; Shang, Ling-Ling; Ma, Rui; Dong, Wan-Li

    2013-07-01

    The preparation conditions of porous ceramics were determined by SEM, XRD and FT-IR characterizations as well as the nickel removal ability of porous ceramics to be: the mass fraction w of sesbania powder doped was 4%, and the calcination temperature was 800 degrees C. SEM and pore structure characterization illustrated that calcination caused changes in the structure and morphology of waste ceramics. With the increase of calcination temperature, the specific surface area and pore volume decreased, while the aperture increased. EDS analyses showed that the main elements of both the original waste porcelain powder and the porous ceramics were Si, Al and O. The SEM, XRD and FT-IR characterization of porous ceramics illustrated that the structure of porous ceramics was stable before and after adsorption. The series of experiments of Ni2+ adsorption using these porous ceramics showed that when the dosage of porous ceramics was 10 g x L(-1), the adsorption time was 60 min, the pH value was 6.32, and the concentration of nickel-containing wastewater was below 100 mg x L(-1), the Ni2+ removal of wastewater reached 89.7%. Besides, the porous ceramics showed higher removal efficiency on nickel in the wastewater. The Ni(2+)-containing wastewater was processed by the porous ceramics prepared, and the adsorption dynamics and adsorption isotherms of Ni2+ in wastewater by porous ceramics were investigated. The research results showed that the Ni2+ adsorption process of porous ceramics was in accordance with the quasi second-order kinetic model (R2 = 0.999 9), with Q(e) of 9.09 mg x g(-1). The adsorption process can be described by the Freundlich equation and Langmuir equation, and when the temperature increased from 20 degrees C to 40 degrees C, the maximum adsorption capacity Q(m) increased from 14.49 mg x g(-1) to 15.38 mg x g(-1).

  9. Comparative Study of Textural Characteristics on Methane Adsorption for Carbon Spheres Produced by CO2 Activation

    Directory of Open Access Journals (Sweden)

    Wen Yang

    2014-01-01

    Full Text Available Resorcinol-formaldehyde resin polymer was used as raw material for preparation of carbon spheres. Samples were treated with CO2 flow at 850°C by varying activation times. The CO2 activation granted better pore development of pore structure. The experimental data of CH4 adsorption as a function of equilibrium pressure was fitted by Langmuir and Dubinin-Astakhov (D-A models. It was concluded that the high surface area and micropore volume of carbon spheres did unequivocally determine methane capacities. In addition, a thermodynamic study of the heat of adsorption of CH4 on the carbon spheres was carried out. Adsorption of CH4 on carbon spheres showed a decrease in the adsorption heat with CH4 occupancy, and the heat of adsorption fell from 20.51 to 12.50 kJ/mol at 298 K and then increased to a little higher values at a very high loading (>0.70, indicating that CH4/CH4 interactions within the adsorption layer became significant.

  10. Synthesis, Characterization and Hexavalent Chromium Adsorption Characteristics of Aluminum- and Sucrose-Incorporated Tobermorite

    Directory of Open Access Journals (Sweden)

    Zhiguang Zhao

    2017-05-01

    Full Text Available Tobermorites were synthesized from the lime-quartz slurries with incorporations of aluminum and sucrose under hydrothermal conditions, and then used for adsorption of Cr(VI. The chemical components, and structural and morphological properties of tobermorite were characterized by X-ray diffraction (XRD, thermogravimetric-differential scanning calorimetry (TG-DSC, Fourier transform infrared spectroscopy (FT-IR, nuclear magnetic resonance (NMR, scanning electron microscopy (SEM, X-ray photoelectron spectroscopic (XPS and N2 adsorption–desorption measurements. The formation and crystallinity of tobermorite could be largely enhanced by adding 2.3 wt.% aluminum hydroxide or 13.3 wt.% sucrose. Sucrose also played a significantly positive role in increasing the surface area. The adsorption performances for Cr(VI were tested using a batch method taking into account the effects of pH, the adsorption kinetics, and the adsorption isotherms. The adsorption capacities of the aluminum- and sucrose-incorporated tobermorites reached up to 31.65 mg/g and 28.92 mg/g, respectively. Thus, the synthesized tobermorites showed good adsorption properties for removal of Cr(VI, making this material a promising candidate for efficient bulk wastewater treatment.

  11. Effect of pyrolysis temperature on characteristics and aromatic contaminants adsorption behavior of magnetic biochar derived from pyrolysis oil distillation residue.

    Science.gov (United States)

    Li, Hao; Mahyoub, Samah Awadh Ali; Liao, Wenjie; Xia, Shuqian; Zhao, Hechuan; Guo, Mengya; Ma, Peisheng

    2017-01-01

    The magnetic biochars were easily fabricated by thermal pyrolysis of Fe(NO3)3 and distillation residue derived from rice straw pyrolysis oil at 400, 600 and 800°C. The effects of pyrolysis temperature on characteristics of magnetic biochars as well as adsorption capacity for aromatic contaminants (i.e., anisole, phenol and guaiacol) were investigated carefully. The degree of carbonization of magnetic biochars become higher as pyrolysis temperature increasing. The magnetic biochar reached the largest surface area and pore volume at the pyrolysis temperature of 600°C due to pores blocking in biochar during pyrolysis at 800°C. Based on batch adsorption experiments, the used adsorbent could be magnetically separated and the adsorption capacity of anisole on magnetic biochars was stronger than that of phenol and guaiacol. The properties of magnetic biochar, including surface area, pore volume, aromaticity, grapheme-like-structure and iron oxide (γ-Fe2O3) particles, showed pronounced effects on the adsorption performance of aromatic contaminants. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. New insight into adsorption characteristics and mechanisms of the biosorbent from waste activated sludge for heavy metals.

    Science.gov (United States)

    Zhou, Yun; Zhang, Zhiqiang; Zhang, Jiao; Xia, Siqing

    2016-07-01

    The adsorption characteristics and mechanisms of the biosorbent from waste activated sludge were investigated by adsorbing Pb(2+) and Zn(2+) in aqueous single-metal solutions. A pH value of the metal solutions at 6.0 was beneficial to the high adsorption quantity of the biosorbent. The optimal mass ratio of the biosorbent to metal ions was found to be 2. A higher adsorption quantity of the biosorbent was achieved by keeping the reaction temperature below 55°C. Response surface methodology was applied to optimize the biosorption processes, and the developed mathematical equations showed high determination coefficients (above 0.99 for both metal ions) and insignificant lack of fit (p=0.0838 and 0.0782 for Pb(2+) and Zn(2+), respectively). Atomic force microscopy analyses suggested that the metal elements were adsorbed onto the biosorbent surface via electrostatic interaction. X-ray photoelectron spectroscopy analyses indicated the presence of complexation (between -NH2, -CN and metal ions) and ion-exchange (between -COOH and metal ions). The adsorption mechanisms could be the combined action of electrostatic interaction, complexation and ion-exchange between functional groups and metal ions. Copyright © 2016. Published by Elsevier B.V.

  13. Effect of supercritical water treatment on porous structure, liquid-phase adsorption and regeneration characteristics of activated anthracite

    Energy Technology Data Exchange (ETDEWEB)

    Tanthapanichakoon, W.; Sittipraneed, S.; Japthong, P.; Charinpanitkul, T.; Boon-Amnuayvitaya, V.; Nakagawa, K.; Tamon, H. [National Nanotechnological Centre, Pathumthani (Thailand)

    2006-06-15

    Microporous activated anthracite was produced from waste anthracite powders by the conventional steam activation. The activated anthracite was also treated by supercritical water reaction (SWR) by using distilled water and hydrogen peroxide solution as a liquid medium for SWR treatment. It was found that SWR treatment can improve the mesoporosity of the activated anthracite though the micropore volume was reduced by the treatment. In liquid-phase adsorption and supercritical water regeneration studies, phenol and organic dye RED 31 were selected as the representative adsorbates. The adsorption and regeneration characteristics of activated anthracite were compared with those of a commercial activated carbon. The results indicate that the activated anthracite prepared showed comparable phenol adsorption capacity but significantly lower dye adsorption capacity than the commercial one. However, supercritical water regeneration efficiency was remarkably high. The first/second regeneration efficiencies of commercial activated carbon and activated anthracite exhausted with phenol were 55/55 and 65/65%, respectively, and in the case of RED 31, 78/79 and 338/317%, respectively, with losses of activated carbon less than 4% per regeneration. Because of little loss of activated carbon during successive regenerations, this SWR regeneration method was suitable for regenerating spent activated carbon or anthracite.

  14. Adsorption characteristics of acetone, chloroform and acetonitrile on sludge-derived adsorbent, commercial granular activated carbon and activated carbon fibers.

    Science.gov (United States)

    Tsai, Jiun-Horng; Chiang, Hsiu-Mei; Huang, Guan-Yinag; Chiang, Hung-Lung

    2008-06-15

    The adsorption characteristics of chloroform, acetone, and acetonitrile on commercial activated carbon (C1), two types of activated carbon fibers (F1 and F2), and sludge adsorbent (S1) was investigated. The chloroform influent concentration ranged from 90 to 7800 ppm and the acetone concentration from 80 to 6900 ppm; the sequence of the adsorption capacity of chloroform and acetone on adsorbents was F2>F1 approximately C1 approximately S1. The adsorption capacity of acetonitrile ranged from 4 to 100 mg/g, corresponding to the influent range from 43 to 2700 ppm for C1, S1, and F1. The acetonitrile adsorption capacity of F2 was approximately 20% higher than that of the other adsorbents at temperaturescarbon fibers is higher than that of the other adsorbents due to their smaller fiber diameter and higher surface area. The micropore diffusion coefficient of VOC on activated carbon and sludge adsorbent was approximately 10(-4) cm2 s(-1). The diffusion coefficient of VOC on carbon fibers ranged from 10(-8) to 10(-7) cm2 s(-1). The small carbon fiber pore size corresponds to a smaller diffusion coefficient.

  15. Greater-than-Class C low-level radioactive waste characterization: Estimated volumes, radionuclide activities, and other characteristics. Revision 1

    Energy Technology Data Exchange (ETDEWEB)

    1994-09-01

    The Department of Energy`s (DOE`s) planning for the disposal of greater-than-Class C low-level radioactive waste (GTCC LLW) requires characterization of the waste. This report estimates volumes, radionuclide activities, and waste forms of GTCC LLW to the year 2035. It groups the waste into four categories, representative of the type of generator or holder of the waste: Nuclear Utilities, Sealed Sources, DOE-Held, and Other Generator. GTCC LLW includes activated metals (activation hardware from reactor operation and decommissioning), process wastes (i.e., resins, filters, etc.), sealed sources, and other wastes routinely generated by users of radioactive material. Estimates reflect the possible effect that packaging and concentration averaging may have on the total volume of GTCC LLW. Possible GTCC mixed LLW is also addressed. Nuclear utilities will probably generate the largest future volume of GTCC LLW with 65--83% of the total volume. The other generators will generate 17--23% of the waste volume, while GTCC sealed sources are expected to contribute 1--12%. A legal review of DOE`s obligations indicates that the current DOE-Held wastes described in this report will not require management as GTCC LLW because of the contractual circumstances under which they were accepted for storage. This report concludes that the volume of GTCC LLW should not pose a significant management problem from a scientific or technical standpoint. The projected volume is small enough to indicate that a dedicated GTCC LLW disposal facility may not be justified. Instead, co-disposal with other waste types is being considered as an option.

  16. Activation of waste MDF sawdust charcoal and its reactive dye adsorption characteristics.

    Science.gov (United States)

    Gan, Q; Allen, S J; Matthews, R

    2004-01-01

    This paper reports an experimental investigation of converting waste medium density fibreboard (MDF) sawdust into chars and activated carbon using chemical activation and thermal carbonisation processes. The MDF sawdust generated during the production of architectural mouldings was characterised and found to have unique properties in terms of fine particle size and high particle density. It also has a high content of urea formaldehyde resin used as a binder in the manufacturing of MDF board. Direct thermal carbonisation and chemical activation of the sawdust by metal impregnation and acid (phosphoric acid) treatment prior to pyrolysis treatment were carried out. The surface morphology of the raw dust, its chars and activated carbon were examined using scanning electron microscopy (SEM). Adsorptive properties and total pore volume of the materials were also analysed using the BET nitrogen adsorption method. Liquid adsorption of a reactive dye (Levafix Brilliant red E-4BA) by the derived sawdust carbon was investigated in batch isothermal adsorption process and the results compared to adsorption on to a commercial activated carbon (Filtrasorb F400). The MDF sawdust carbon exhibited in general a very low adsorption capacity towards the reactive dye, and physical characterisation of the carbon revealed that the conventional chemical activation and thermal carbonisation process were ineffective in developing a microporous structure in the dust particles. The small size of the powdery dust, the high particle density, and the presence of the urea formaldehyde resin all contributed to the difficulty of developing a proper porous structure during the thermal and chemical activation process. Finally, activation of the dust material in a consolidated form (cylindrical pellet) only achieved very limited improvement in the dye adsorption capacity. This original study, reporting some unexpected outcomes, may serve as a stepping-stone for future investigations of recycle and

  17. Evaluation of iodide and iodate for adsorption-desorption characteristics and bioavailability in three types of soil.

    Science.gov (United States)

    Hong, Chunlai; Weng, Huanxin; Jilani, Ghulam; Yan, Ailan; Liu, Huiping; Xue, Zhiyong

    2012-05-01

    Adsorption-desorption of iodine in two forms, viz., iodide (I(-)) and iodate (IO (3) (-) ), in three types of soil were investigated. The soils were: red soil developed on Quaternary red earths (REQ)- clayey, kaolintic thermic plinthite Aquult, Inceptisol soil (IS) and alluvial soil (AS)-Fluvio-marine yellow loamy soil. The isothermal curves of iodine adsorption on soils were described by Langmuir and Freundlich equation, and the maximum adsorption values (y (m)) were obtained from the simple Langmuir model. As compared with the iodide, the iodate was adsorbed in higher amounts by the soils tested. Among three soils, the REQ soil adsorbed more iodine (I(-) and IO (3) (-) ) than the IS and AS. The distribution coefficient (K (d)) of iodine in the soils decreased exponentially with increasing iodine loading concentration. Desorption of iodine in soil was increased correspondingly with increasing adsorption values. The REQ soil had a greater affinity for iodine than the IS and AS at the same iodine loadings. In the pot experiment cultivated with pakchoi (Brassica chinensis L.) and added with two exogenous iodine sources, the iodide form was quickly taken up by pakchoi and caused more toxicity to the vegetable. The rate of iodine loss from soil was higher for iodide form as compared with the iodate. The iodine bioavailability was the highest but the persistence was the weakest in AS among the three soils tested, and the REQ soil showed just the opposite trend to that of the AS soil. This study is of theoretical importance to understand the relationship between iodine adsorption-desorption characteristics and their bioavailability in different soils and it also has practical implications for seeking effective alternatives of iodine biofortification to prevent iodine deficiency disorders.

  18. Activated carbons prepared from refuse derived fuel and their gold adsorption characteristics.

    Science.gov (United States)

    Buah, William K; Williams, Paul T

    2010-02-01

    Activated carbons produced from refuse derived fuel (RDF), which had been prepared from municipal solid waste have been characterized and evaluated for their potential for gold adsorption from gold chloride solution. Pyrolysis of the RDF produced a char, which was then activated via steam gasification to produce activated carbons. Steam gasification of the char at 900 degrees C for 3 h yielded 73 wt% activated carbon. The derived activated carbon had a surface area of 500 m2 g(-1) and a total pore volume of 0.19 cm3 g(-1). The gold adsorption capacity of the activated carbon was 32.1 mg Au g(-1) of carbon when contacted with an acidified gold chloride solution. The gold adsorption capacity was comparable to that of a commercial activated carbon tested under the same conditions and was well in the range of values of activated carbons used in the gold industry. Demineralization of the RDF activated carbon in a 5 M HCl solution resulted in enhancement of its textural properties but a reduction in the gold adsorption rate, indicating that the metal content of the RDF activated carbon influenced its gold adsorption rate.

  19. Studies of Adsorption Characteristics of Activated Carbons in between 4.5 to 10 K for Cryopump Applications

    Science.gov (United States)

    Krishnamoorthy, V.; Swarup Udgata, Satya; Shankar Tripathi, Vijai; Gangradey, Ranjana; Kasthurirengan, Srinivasan; Behera, Upendra

    2012-11-01

    Cryosorption pump is the only solution to pump helium, hydrogen and its isotopes in fusion devices. To design such pumps, knowledge of adsorption characteristics of activated carbons in the temperature range from 4.5 to 77 K is needed, but is very scarce in the open literature. Hence an experimental setup is designed and developed to measure adsorption characteristics of activated carbons down to 4.5 K. For this purpose, a commercial micropore analyzer operating down to 77K is coupled to a two-stage GM cryocooler, to enable cooling the sample temperature down to 4.5 K. A heat switch is mounted in between the second stage cold head and the sample chamber helps to vary the sample temperature from 4.5 K to 77K without affecting the performance of the cryocooler. The details of the experimental setup is presented elsewhere. We present here the experimental results of adsorption of different types of activated carbons in the temperature range 4.5K to 10 K using Helium gas as adsorbate. These results are evaluated in terms of surface area, pore sizes and their distributions. Also the effect of epoxy based adhesive used in bonding the activated carbons to the panels is evaluated. These results will be useful towards the selection of the right activated carbons for the development of cryosorption pumps.

  20. Thermodynamic characteristics of the adsorption of 1,3,4-oxadiazoles and 1,2,4,5-tetrazines from methanol and water-methanol solutions onto hypercrosslinked polystyrene

    Science.gov (United States)

    Saifutdinov, B. R.; Davankov, V. A.; Il'in, M. M.

    2017-03-01

    The thermodynamic characteristics of the adsorption of several 1,3,4-oxadiazoles and 1,2,4,5- tetrazines from methanol and water-methanol solutions onto neutral hypercrosslinked polystyrene with a degree of crosslinking of 150% are determined via high performance liquid chromatography. It is shown how the obtained characteristics depend on the molecular structure of adsorbed substances and the composition of the liquid phase in which adsorption occurs.

  1. Adsorption characteristics of PCBs to resins, whole cells, cell and tissue components, and biomolecules

    Energy Technology Data Exchange (ETDEWEB)

    Kelley, R.L.; Conrad, J.; Akin, C.

    1990-01-01

    Polychlorinated biphenyls (PCBs) have been designated hazardous chemicals by the US Environmental Protection Agency (EPA). Although PCBs and PCB-containing oils have not been in use since 1977, they persist in the environment. They are known to be absorbed by various aquatic organisms, birds, and mammals. The nature of these affinities is not known. In this study, the Institute of Gas Technology (IGT) compared the adsorption phenomenon of PCBs on commercial resins, whole bacterial cells, cell and tissue component, and various biomolecules. Adsorption and desorption of PCBs to biomolecules and resins in both aqueous and nonaqueous conditions were examined. 9 refs., 7 figs., 2 tabs.

  2. Osteopetrosis: Radiological & Radionuclide Imaging

    Science.gov (United States)

    Sit, Cherry; Agrawal, Kanhaiyalal; Fogelman, Ignac; Gnanasegaran, Gopinath

    2015-01-01

    Osteopetrosis is a rare inherited bone disease where bones harden and become abnormally dense. While the diagnosis is clinical, it also greatly relies on appearance of the skeleton radiographically. X-ray, radionuclide bone scintigraphy and magnetic resonance imaging have been reported to identify characteristics of osteopetrosis. We present an interesting case of a 59-year-old man with a history of bilateral hip fractures. He underwent 99mTc-methylene diphosphonate whole body scan supplemented with single-photon emission computed tomography/computed tomography of spine, which showed increased uptake in the humeri, tibiae and femora, which were in keeping with osteopetrosis. PMID:25589808

  3. Osteopetrosis: radiological & radionuclide imaging.

    Science.gov (United States)

    Sit, Cherry; Agrawal, Kanhaiyalal; Fogelman, Ignac; Gnanasegaran, Gopinath

    2015-01-01

    Osteopetrosis is a rare inherited bone disease where bones harden and become abnormally dense. While the diagnosis is clinical, it also greatly relies on appearance of the skeleton radiographically. X-ray, radionuclide bone scintigraphy and magnetic resonance imaging have been reported to identify characteristics of osteopetrosis. We present an interesting case of a 59-year-old man with a history of bilateral hip fractures. He underwent (99m)Tc-methylene diphosphonate whole body scan supplemented with single-photon emission computed tomography/computed tomography of spine, which showed increased uptake in the humeri, tibiae and femora, which were in keeping with osteopetrosis.

  4. ADSORPTION CHARACTERISTIC OF IRON ONTO POLY[EUGENOL-CO-(DIVINYL BENZENE] FROM AQUEOUS SOLUTION

    Directory of Open Access Journals (Sweden)

    Fitrilia Silvianti

    2017-09-01

    • Zou, X.; Pan, J.; Ou, H.; Wang, X.;Guan, W.; Li, C.; Yan, Y.; Duan, Y. Adsorptive removal of Cr(III and Fe(III from aqueous solution by chitosan/attapulgite composites: Equilibrium, thermodynamics and kinetics. Chem. Eng. J. 2011, 167: 112-121, DOI: 10.1016/j.cej.2010.12.009

  5. Synthesis and adsorption characteristics of an heterogenized manganese nanoadsorbent towards methyl orange.

    Science.gov (United States)

    Arshadi, M; Mehravar, M; Amiri, M J; Faraji, A R

    2015-02-15

    Heterogeneous Mn nanoparticles (5-30 nm diameter) is found to be a nanomaterial for the rapid removal of large quantities of toxic dye (methyl orange) from aqueous solution, with wide ranging potential applications. The synthesized materials were characterized with different methods such as FT-IR spectroscopy, CHN elemental analysis, BET, SEM, TEM, ICP-OES and EPR. The contact time to obtain equilibrium for maximum adsorption of methyl orange was 20 min. EPR of Mn ions evidenced that most of the covalently bond active sites of the nano-adsorbent are in the form of Mn(III) ions at the surface. The heterogeneous Mn(III)-Cl ions were found to be effective adsorbent for the removal of methyl orange from solution. The adsorption of methyl orange ions has been studied in terms of pseudo-first-order and pseudo-second-order kinetics, and the Freundlich, Langmuir and Langmuir-Freundlich isotherm models have also been applied to the equilibrium adsorption data. The adsorption process was spontaneous and endothermic in nature and followed pseudo-second-order kinetic model.

  6. Removal and adsorption characteristics of polyvinyl alcohol from aqueous solutions using electrocoagulation

    Energy Technology Data Exchange (ETDEWEB)

    Chou, Wei-Lung, E-mail: wlchou@sunrise.hk.edu.tw [Department of Safety, Health and Environmental Engineering, Hungkuang University, Sha-Lu, Taichung 433, Taiwan (China)

    2010-05-15

    The study was to investigate the performance of electrocoagulation (EC) for the efficient removal of polyvinyl alcohol (PVA) from aqueous solutions. Several parameters were evaluated to characterize the PVA removal efficiency, such as various electrode pairs, current densities, supporting electrolytes, temperatures, and initial electrolyte concentrations. The effects of the current density, supporting electrolyte, and temperature on the electrical energy consumption were also investigated. The experimental results indicate that a Fe/Al electrode pair is the optimum choice out of four different electrode pair combinations. The optimum current density, supporting electrolyte concentration, and temperature were found to be 5 mA cm{sup -2}, 0.008N NaCl, and 298 K, respectively. The PVA removal efficiency decreased with increasing in the initial concentrations. The kinetic studies indicated that the EC process was best described using pseudo-second-order kinetics. The experimental data were also compared to different adsorption isotherm models in order to describe the EC process. The adsorption of PVA was best fitted by the Langmuir adsorption isotherm model. Thermodynamic parameters such as the Gibbs free energy, enthalpy, and entropy indicated that the adsorption of PVA on metal hydroxides was feasible, spontaneous and endothermic in the temperature range of 288-318 K.

  7. Removal and adsorption characteristics of polyvinyl alcohol from aqueous solutions using electrocoagulation.

    Science.gov (United States)

    Chou, Wei-Lung

    2010-05-15

    The study was to investigate the performance of electrocoagulation (EC) for the efficient removal of polyvinyl alcohol (PVA) from aqueous solutions. Several parameters were evaluated to characterize the PVA removal efficiency, such as various electrode pairs, current densities, supporting electrolytes, temperatures, and initial electrolyte concentrations. The effects of the current density, supporting electrolyte, and temperature on the electrical energy consumption were also investigated. The experimental results indicate that a Fe/Al electrode pair is the optimum choice out of four different electrode pair combinations. The optimum current density, supporting electrolyte concentration, and temperature were found to be 5 mA cm(-2), 0.008 N NaCl, and 298 K, respectively. The PVA removal efficiency decreased with increasing in the initial concentrations. The kinetic studies indicated that the EC process was best described using pseudo-second-order kinetics. The experimental data were also compared to different adsorption isotherm models in order to describe the EC process. The adsorption of PVA was best fitted by the Langmuir adsorption isotherm model. Thermodynamic parameters such as the Gibbs free energy, enthalpy, and entropy indicated that the adsorption of PVA on metal hydroxides was feasible, spontaneous and endothermic in the temperature range of 288-318 K.

  8. Formation Mechanism of alpha-Fe2O3 Nanotubes via Electrospinning and Their Adsorption Characteristics of BSA and DNA.

    Science.gov (United States)

    Liu, Ruijiang; Wang, Peng; Tao, Yuting; Liu, Yifan; Shen, Xiangqian

    2016-02-01

    The alpha-Fe2O3 nanotubes with diameters of 400-700 nm have been prepared via the sol-gel assisted electrospinning and subsequent one-step heat treatment with ferric nitrate, ethanol and poly(vinyl pyrrolidone) as starting regents. The resultant alpha-Fe2O3 nanotubes were characterized by XRD, SEM, TEM, and VSM techniques. The hollow structure is mainly influenced by the water content in the gel precursor and the heating rate, and the hollow formation mechanism of alpha-Fe2O9 nanotubes is discussed. Adsorption of BSA onto the as-prepared alpha-Fe2O3 nanotubes exhibits a good capacity of 56.5 mg/g with the initial BSA concentration of 1.0 mg/mL, which demonstrates their feasibility in delivery of biomacromolecules. Subsequently, the adsorption characteristics of DNA onto the alpha-Fe2O3 nanotubes were investigated, and the adsorbance of DNA can achieve a maximum value of 4.19 microg/g when the initial DNA concentration is 50 microg/mL. The adsorption process of DNA onto alpha-Fe2O3 nanotubes can be described well by the pseudo-first-order kinetic model at room temperature according to the correlation coefficient R2 = 0.9978.

  9. Numerical Analysis on Adsorption Characteristics of Activated Carbon/Ethanol Pair in Finned Tube Type Adsorber

    Science.gov (United States)

    Makimoto, Naoya; Kariya, Keishi; Koyama, Shigeru

    The cycle performance of adsorption cooling system depends on the thermophysical properties of the adsorbent/refrigerant pair and configuration of the adsorber/desorber heat exchanger. In this study, a twodimensional analysis is carried out in order to clarify the performance of the finned tube type adsorber/desorber heat exchanger using a highly porous activated carbon powder (ACP)/ethanol pair. The simulation results show that the average cooling capacity per unit volume of adsorber/desorber heat exchanger and coefficient of performance (COP) can be improved by optimizing fin thickness, fin height, fin pitch and tube diameter. The performance of a single stage adsorption cooling system using ACP/ethanol pair is also compared with that of activated carbon fiber (ACF)/ethanol pair. It is found that the cooling capacities of each adsorbent/refrigerant pair increase with the decrease of adsorption/desorption time and the cooling capacity of ACP/ethanol pair is approximately 2.5 times as much as that of ACF/ethanol pair. It is also shown that COP of ACP/ethanol pair is superior to that of ACF/ethanol pair.

  10. 稻秸对Pb2+的吸附特性%Adsorption Characteristics of Pb2+on Rice Straw

    Institute of Scientific and Technical Information of China (English)

    杨军; 张玉龙; 杨丹; 刘鸣达

    2012-01-01

    To explore the adsorption characteristics of Pb2+ on rice straw, the effects of environmental factors including adsorption time, initial concentration of metal ions, rice straw dosage, initial pH and temperature on metal biosorption were studied. In addition, the relevant equilibrium , kinetics and thermodynamics were discussed. The results showed that the adsorption of Pb2+ on rice straw was a very fast process which could be expressed well by the pseudo-second-order equation. The removal rate of Pb2+ was up to 85.64% at 60 minutes. The adsorption isotherms were in good agreement with the Langmuir and Freundlich models, though the latter was better. The maximum adsorption capacity for Pb2+ reached 13. 67 mg/g using the Langmuir model. With the increase of rice straw dosage, the removal rate of Pb2+ increased. The pH had a prominent effect on the adsorption of Pb2+; the removal rate reached over 92% when the pH was between 4 and 6. Temperature had no significant effect on the adsorption of Pb2+ . Thennodynamic analysis showed that the adsorption process was spontaneous, exothermic and entropy increasing.%为探讨稻秸对废水中Pb2+的吸附特性,通过静态试验研究了吸附时间、离子浓度、吸附剂用量、初始pH和温度对稻秸吸附Pb2+的影响,并分析了其吸附动力学、等温吸附平衡及热力学特征.结果表明:稻秸吸附Pb2+的过程进行得很快,60 min时去除率达到85.64%,其吸附动力学过程以准二级动力学方程拟合效果最好;吸附等温线符合Langmuir和Freundlich等温吸附模型,其中以Freundlich模型为最优,与吸附强度有关的常数在2~10之间,吸附容易发生,而使用Langmuir模型拟合最大吸附量的理论值可达13.67 mg/g;随着稻秸投加量的增加,Pb2+的去除率逐渐增加,单位吸附量逐渐减小;溶液初始pH对稻秸吸附Pb2+的影响较大,pH在4~6时去除率可达92%以上;稻秸对Pb2+的吸附受温度影响较

  11. Fluidization characteristics of and protein adsorption on fluoride-modified porous zirconium oxide particles.

    Science.gov (United States)

    Griffith, C M; Morris, J; Robichaud, M; Annen, M J; McCormick, A V; Flickinger, M C

    1997-08-01

    Porous zirconia particles of specific gravity approximately 3.2 g/ml, mean particle sizes of approximately 50 microns, and terminal settling velocity of approximately 2.8 mm/s in water, were synthesized using an oil emulsion method from 1000 A colloids and were evaluated for their potential use in expanded bed protein adsorption. Expanded beds of particles were stable even for small volume, shallow beds (settled bed: 10 ml, height to diameter ratio fluidization velocities common to much larger particles (210 cm/h for a three-fold bed expansion). When the surface of these particles was modified by fluoride adsorption, the total bed capacity for bovine serum albumin (BSA) adsorption was 42 +/- 2 mg BSA/ml of settled bed volume at linear velocities of 109-210 cm/h. Residence time distribution studies of several solutes under non-binding conditions were performed to assess the degree of liquid mixing and channeling in the expanded bed as a function of fluidization velocity. Liquid mixing and channeling were also studied as a function of distributor design. With these very dense particles, the degree of channeling and mixing did not worsen with the degree of expansion. Elution of adsorbed BSA while the bed was expanded (by a step increase in ionic strength) was rapid resulting in a narrow peak at high fluidization velocities without resorting to settling of the bed. The dynamic binding capacity of BSA at 5% breakthrough (protein effluent concentration equal to 5% of the inlet concentration) was the same for a two-fold expanded bed as for a settled bed (22 +/- 2 mg BSA/ml of settled bed volume), though it decreased for higher bed expansions. BSA binding was reproducible following repeated cleaning of the adsorbent with 0.25 M sodium hydroxide.

  12. Production of a new adsorbent from Moroccan oil shale by chemical activation and its adsorption characteristics for U and Th bearing species

    Science.gov (United States)

    Khouya, E.; Fakhi, S.; Hannache, H.; Ichcho, S.; Pailler, R.; Naslain, R.; Abbe, J. C.

    2005-03-01

    New adsorbents were prepared from Moroccan oil shale of Tarfaya (layer R3) by chemical activation with sulphuric acid diluted at 80%. The influence of activation temperature, atmosphere gas, holding time in oven and weight ratio of sulphuric acid to precursor was investigated by determination of yield of adsorbents and adsorption capacity of methylene blue. The best adsorbent properties were found for a particular combination of the chosen parameters: temperature and time of activation respectively equal to 250° C and 2 hours, the gas vector being nitrogen (N{2}). The adsorption capacity for methylene blue and specific surface (SBET) of the new adsorbent were equal to 300 mg/g and 270 m2/g respectively. The batch mode experiment was used to explore the feasibility of this adsorbent for removal of radionuclides (U and Th) from aqueous solution. Applicability of the adsorbent was examined for synthetic solution prepared from hydrated uranyl nitrate (UO{2}(NO{3})2.6H{2}O) and hydrated thorium nitrate (Th(NO{3})4.5H{2}O). The parameters of adsorption for the two radioelements were determined by application of the Langmuir, Freundlich and Elovich models.

  13. Production of a new adsorbent from Moroccan oil shale by chemical activation and its adsorption characteristics for U and Th bearing species

    Energy Technology Data Exchange (ETDEWEB)

    Khouya, E.; Hannache, H.; Ichcho, S. [Faculte des Sciences Ben M' sik, Lab. des Materiaux Thermostructuraux, Casablanca (Morocco); Khouya, E.; Fakhi, S. [Faculte des Sciences Ben M' sik, Lab. de Radiochimie, Casablanca (Morocco); Pailler, R.; Naslain, R. [Bordeaux-1 Univ., Lab. des Composites Thermostructuraux, UMR 5801 CNRS-CEA-SNECMA, 33 (France); Abbe, J.C. [Ecole des Mines de Nantes, Lab. d' Analyse Subatech, 44 (France)

    2005-03-01

    New adsorbents were prepared from Moroccan oil shale of Tarfaya (layer R3) by chemical activation with sulphuric acid diluted at 80%. The influence of activation temperature, atmosphere gas, holding time in oven and weight ratio of sulphuric acid to precursor was investigated by determination of yield of adsorbents and adsorption capacity of methylene blue. The best adsorbent properties were found for a particular combination of the chosen parameters: temperature and time of activation respectively equal to 250 C and 2 hours, the gas vector being nitrogen (N{sub 2}). The adsorption capacity for methylene blue and specific surface (S{sub BET}) of the new adsorbent were equal to 300 mg/g and 270 m{sup 2}/g respectively. The batch mode experiment was used to explore the feasibility of this adsorbent for removal of radionuclides (U and Th) from aqueous solution. Applicability of the adsorbent was examined for synthetic solution prepared from hydrated uranyl nitrate (UO{sub 2}(NO{sub 3}){sub 2}.6H{sub 2}O) and hydrated thorium nitrate (Th(NO{sub 3}){sub 4}.5H{sub 2}O). The parameters of adsorption for the two radioelements were determined by application of the Langmuir, Freundlich and Elovich models. (authors)

  14. Factors affecting the distribution of natural and anthropogenic radionuclides in the coastal Burullus Lake.

    Science.gov (United States)

    El-Reefy, H I; Badran, H M; Sharshar, T; Hilal, M A; Elnimr, T

    2014-08-01

    In the present study, measurements of naturally occurring radioactive materials and (137)Cs activity in sediment were conducted for locations covering the entire Burullus Lake in order to gather information about radionuclides mobility and distribution. Low-background γ-spectrometry was employed to determine the activity concentrations of water and sediment samples. The activity concentrations of (226)Ra and (232)Th are close to uniform distribution in the lake environment. Among the different physical and chemical characteristics measured for water and sediment, only salinity and total organic matter content have the potential to affect the mobility of (137)Cs and (40)K. The results suggest that these two radionuclides are attached to different mobile particulates. Increasing salinity tends to strengthen the adsorption of (137)Cs and solubilization of (40)K in sediment. On the other hand, sediment with high organic matter content traps (137)Cs and (40)K associated particulates to bottom sediment.

  15. Rapeseed and Raspberry Seed Cakes as Inexpensive Raw Materials in the Production of Activated Carbon by Physical Activation: Effect of Activation Conditions on Textural and Phenol Adsorption Characteristics

    Directory of Open Access Journals (Sweden)

    Koen Smets

    2016-07-01

    Full Text Available The production of activated carbons (ACs from rapeseed cake and raspberry seed cake using slow pyrolysis followed by physical activation of the obtained solid residues is the topic of this study. The effect of activation temperature (850, 900 and 950 °C, activation time (30, 60, 90 and 120 min and agent (steam and CO2 on the textural characteristics of the ACs is investigated by N2 adsorption. In general, higher activation temperatures and longer activation times increase the BET specific surface area and the porosity of the ACs, regardless of the activation agent or raw material. Steam is more reactive than CO2 in terms of pore development, especially in the case of raspberry seed cake. The performance of the ACs in liquid adsorption is evaluated by batch phenol adsorption tests. Experimental data are best fitted by the Freundlich isotherm model. Based on total yield, textural characteristics and phenol adsorption, steam activation at 900 °C for 90 min and CO2 activation at 900 °C for 120 min are found as the best activation conditions. Raspberry seed cake turns out to be a better raw material than rapeseed cake. Moreover, AC from raspberry seed cake produced by steam activation at 900 °C for 90 min performs as well as commercial AC (Norit GAC 1240 in phenol adsorption. The adsorption kinetics of the selected ACs are best fitted by the pseudo-second-order model.

  16. Development of long-lived radionuclide partitioning technology

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Jae Hyung; Lee, Eil Hee; Kim, Kwang Wook; Yang, Han Beom; Chung, Dong Yong; Lim, Jae Kwan; Shin, Young Jun; Kim, Heung Ho; Kown, Sun Gil; Kim, Young Hwan; Hwang, Doo Seung

    1996-07-01

    This study has been focused on the development of unit processes for partitioning in the 1st stage, and experimentally carried out to examine the separation characteristics and operation conditions on the following unit processes. (1) Removal of a small amount of uranium by extraction with TBP, (2) Removal of Zr and Mo and destruction of nitric acid by uranium by denitration with formic acid, (3) Co-precipitation of Am, Np and RE oxalic acid, (4) Dissolution and destruction of oxalate by hydrogen peroxide, (5) Co-extraction of Am, Np and RE by nitric acid, (8) Back-extraction of Np by oxalic acid, (9) Adsorption and elution of Cs and Sr by zeolite, and (10) Advanced separation of radionuclide by electrochemical REDOX method. The results obtained from each unit process will be use as the basic materials for the establishment of optimal partitioning and design of process equipment. (author). 46 refs., 54 tabs., 222 figs.

  17. Development of long-lived radionuclide partitioning technology

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Jae Hyung; Lee, Eil Hee; Kim, Kwang Wook; Yang, Han Beom; Chung, Dong Yong; Lim, Jae Kwan; Shin, Young Jun; Kim, Heung Ho; Kown, Sun Gil; Kim, Young Hwan; Hwang, Doo Seung

    1996-07-01

    This study has been focused on the development of unit processes for partitioning in the 1st stage, and experimentally carried out to examine the separation characteristics and operation conditions on the following unit processes. (1) Removal of a small amount of uranium by extraction with TBP, (2) Removal of Zr and Mo and destruction of nitric acid by uranium by denitration with formic acid, (3) Co-precipitation of Am, Np and RE oxalic acid, (4) Dissolution and destruction of oxalate by hydrogen peroxide, (5) Co-extraction of Am, Np and RE by nitric acid, (8) Back-extraction of Np by oxalic acid, (9) Adsorption and elution of Cs and Sr by zeolite, and (10) Advanced separation of radionuclide by electrochemical REDOX method. The results obtained from each unit process will be use as the basic materials for the establishment of optimal partitioning and design of process equipment. (author). 46 refs., 54 tabs., 222 figs.

  18. Adsorption and Deactivation Characteristics of Cu/ZnO-Based Catalysts for Methanol Synthesis from Carbon Dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Natesakhawat, Sittichai; Ohodnicki, Paul R; Howard, Bret H; Lekse, Jonathan W; Baltrus, John P; Matranga, Christopher

    2013-07-09

    The adsorption and deactivation characteristics of coprecipitated Cu/ZnO-based catalysts were examined and correlated to their performance in methanol synthesis from CO₂ hydrogenation. The addition of Ga₂O₃ and Y₂O₃ promoters is shown to increase the Cu surface area and CO₂/H₂ adsorption capacities of the catalysts and enhance methanol synthesis activity. Infrared studies showed that CO₂ adsorbs spontaneously on these catalysts at room temperature as both monoand bi-dentate carbonate species. These weakly bound species desorb completely from the catalyst surface by 200 °C while other carbonate species persist up to 500 °C. Characterization using N₂O decomposition, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM) with energy-dispersive X-ray spectroscopy (EDX) analysis clearly indicated that Cu sintering is the main cause of catalyst deactivation. Ga and Y promotion improves the catalyst stability by suppressing the agglomeration of Cu and ZnO particles under pretreatment and reaction conditions.

  19. Adsorption characteristics of cadmium(II) onto functionalized poly(hydroxyethylmethacrylate)-grafted coconut coir pith.

    Science.gov (United States)

    Anirudhan, Thayyath Sreenivasan; Divya, Lekshmi; Rijith, Sreenivasan

    2010-07-01

    This study explored the feasibility of utilizing a novel adsorbent, poly(hydroxyethylmethacrylate)-grafted coconut coir pith with carboxyl functionality (PGCP-COOH) for the removal of cadmium(II) from water and wastewater. Maximum removal of 99.9% was observed for an initial concentration of 25 mg/L at pH 6.0 and adsorbent dose of 2.0 g/L. The first-order reversible kinetic model and Langmuir isotherm model were resulted in high correlation coefficients and described well the adsorption of Cd(II) onto PGCP-COOH. The complete removal of 22.4 mg/L Cd(II) from fertilizer industry wastewater was achieved by 2.0 g/L PGCP-COOH. The reusability of the PGCP-COOH for several cycles was demonstrated using 0.1 M HCl solution.

  20. Structural and elastic properties and stability characteristics of oxygenated carbon nanotubes under physical adsorption of polymers

    Energy Technology Data Exchange (ETDEWEB)

    Ansari, R., E-mail: r_ansari@guilan.ac.ir [Department of Mechanical Engineering, University of Guilan, P.O. Box 3756, Rasht (Iran, Islamic Republic of); Ajori, S. [Department of Mechanical Engineering, University of Guilan, P.O. Box 3756, Rasht (Iran, Islamic Republic of); Rouhi, S. [Department of Mechanical Engineering, Langroud Branch, Islamic Azad University, Langroud (Iran, Islamic Republic of)

    2015-03-30

    Highlights: • Buckling of functionalized CNTs under physical adsorption of polymer is studied. • Molecular dynamics simulations are employed for the study. • Values of the critical buckling load and critical strain are shown to increase. • Values of Young's modulus and their variations are dependent on adsorbed polymer type. - Abstract: The importance of covalent and non-covalent functionalization approaches for modification the properties of carbon nanotubes is being more widely recognized. To this end, elastic properties and buckling behavior of oxygenated CNT with atomic oxygen and hydroxyl under physical adsorption of PE (Polyethylene) and PEO (Poly (ethylene oxide)) are determined through employing the molecular dynamics (MD) simulations. The results demonstrate that non-covalent bonding of polymer on the surface of oxygenated CNT causes reductions in the variations of critical buckling load and critical strain compared to oxygenated CNTs. Critical buckling load and critical strain of oxygenated CNT/polymer are higher than those of oxygenated CNT. Also, it is demonstrated that critical buckling load and critical strain values in the case of oxygenated CNT/polymer are independent of polymer type unlike the value of Young's modulus. It is shown that variations of Young's modulus decrease as PE adsorbed on the surface of oxygenated CNT. Moreover, the presence of oxygen atom on PEO chain leads to bigger variations of Young's modulus with weight percentage of chemisorbed component, i.e. atomic oxygen and hydroxyl. It is also demonstrated that Young's modulus reduces more considerably in the presence of PEO chain compared to PE one.

  1. Hydrogeochemistry of Groundwater and Arsenic Adsorption Characteristics of Subsurface Sediments in an Alluvial Plain, SW Taiwan

    Directory of Open Access Journals (Sweden)

    Libing Liao

    2016-12-01

    Full Text Available Many studies were conducted to investigate arsenic mobilization in different alluvial plains worldwide. However, due to the unique endemic disease associated with arsenic (As contamination in Taiwan, a recent research was re-initiated to understand the transport behavior of arsenic in a localized alluvial plain. A comprehensive approach towards arsenic mobility, binding, and chemical speciation was applied to correlate groundwater hydrogeochemistry with parameters of the sediments that affected the As fate and transport. The groundwater belongs to a Na-Ca-HCO3 type with moderate reducing to oxidizing conditions (redox potential = −192 to 8 mV. Groundwater As concentration in the region ranged from 8.89 to 1131 μg/L with a mean of 343 ± 297 μg/L, while the As content in the core sediments varied from 0.80 to 22.8 mg/kg with a mean of 9.9 ± 6.2 mg/kg. A significant correlation was found between As and Fe, Mn, or organic matter, as well as other elements such as Ni, Cu, Zn, and Co in the core sediments. Sequential extraction analysis indicated that the organic matter and Fe/Mn oxyhydroxides were the major binding pools of As. Batch adsorption experiments showed that the sediments had slightly higher affinity for As(III than for As(V under near neutral pH conditions and the As adsorption capacity increased as the contents of Fe oxyhydroxides as well as the organic matter increased.

  2. Mathematical simulation of sediment and radionuclide transport in estuaries

    Energy Technology Data Exchange (ETDEWEB)

    Onishi, Y.; Trent, D.S.

    1982-11-01

    The finite element model LFESCOT (Flow, Energy, Salinity, Sediment and Contaminant Transport Model) was synthesized under this study to simulate radionuclide transport in estuaries to obtain accurate radionuclide distributions which are affected by these factors: time variance, three-dimensional flow, temperature, salinity, and sediments. Because sediment transport and radionuclide adsorption/desorption depend strongly on sizes or types of sediments, FLESCOT simulates sediment and a sediment-sorbed radionuclide for the total of three sediment-size fractions (or sediment types) of both cohesive and noncohesive sediments. It also calculates changes of estuarine bed conditions, including bed elevation changes due to sediment erosion/deposition, and three-dimensional distributions of three bed sediment sizes and sediment-sorbed radionuclides within the bed. Although the model was synthesized for radionuclide transport, it is general enough to also handle other contaminants such as heavy metals, pesticides, or toxic chemicals. The model was checked for its capability for flow, water surface elevation change, salinity, sediment and radionuclide transport under various simple conditions first, confirming the general validity of the model's computational schemes. These tests also revealed that FLESCOT can use large aspect ratios of computational cells, which are necessary in handling long estuarine study areas. After these simple tests, FLESCOT was applied to the Hudson River estuary between Chelsea and the mouth of the river to examine how well the model can predict radionuclide transport through simulating tidally influenced three-dimensional flow, salinity, sediment and radionuclide movements with their interactions.

  3. Evaluation of radon adsorption characteristics of a coconut shell-based activated charcoal system for radon and thoron removal applications.

    Science.gov (United States)

    Karunakara, N; Sudeep Kumara, K; Yashodhara, I; Sahoo, B K; Gaware, J J; Sapra, B K; Mayya, Y S

    2015-04-01

    Radon ((222)Rn), thoron ((220)Rn), and their decay products contribute a major fraction (more than 50%) of doses received from ionisation radiation in public domain indoor environments and occupation environments such as uranium mines, thorium plants, and underground facilities, and are recognised as important radiological hazardous materials, which need to be controlled. This paper presents studies on the removal of (222)Rn and (220)Rn from air using coconut shell-based granular activated charcoal cylindrical adsorber beds. Experiments were conducted to evaluate the (222)Rn and (220)Rn adsorption characteristics, and the mitigation efficiency of coconut-based activated charcoal available in India. The performance parameters evaluated include breakthrough time (τ) and adsorption coefficient (K), and degassing characteristics of the charcoal bed of varying dimensions at different flow rates. While the breakthrough for (222)Rn occurred depending on the dimension of the adsorber bed and flow rates, for (220)Rn, the breakthrough did not occur. The breakthrough curve exhibited a stretched S-shape response, instead of the theoretically predicted sharp step function. The experiments confirm that the breakthrough time individually satisfies the quadratic relationship with respect to the diameter of the bed, and the linear relationship with respect to the length, as predicted in the theory. The K value varied in the range of 2.3-4.12 m(3) kg(-1) with a mean value of 2.99 m(3) kg(-1). The K value was found to increase with the increase in flow rate. Heating the charcoal to ∼ 100 °C resulted in degassing of the adsorbed (222)Rn, and the K of the degassed charcoal and virgin charcoal were found to be similar with no deterioration in performance indicating the re-usability of the charcoal.

  4. Quantitative radionuclide angiocardiography

    Energy Technology Data Exchange (ETDEWEB)

    Scholz, P.M.; Rerych, S.K.; Moran, J.F.; Newman, G.E.; Douglas, J.M.; Sabiston, D.C. Jr.; Jones, R.H.

    1980-01-01

    This study introduces a new method for calculating actual left ventricular volumes and cardiac output from data recorded during a single transit of a radionuclide bolus through the heart, and describes in detail current radionuclide angiocardiography methodology. A group of 64 healthy adults with a wide age range were studied to define the normal range of hemodynamic parameters determined by the technique. Radionuclide angiocardiograms were performed in patients undergoing cardiac catherization to validate the measurements. In 33 patients studied by both techniques on the same day, a close correlation was documented for measurement of ejection fraction and end-diastolic volume. To validate the method of volumetric cardiac output calcuation, 33 simultaneous radionuclide and indocyanine green dye determinations of cardiac output were performed in 18 normal young adults. These independent comparisons of radionuclide measurements with two separate methods document that initial transit radionuclide angiocardiography accurately assesses left ventricular function.

  5. Characteristic and mercury adsorption of activated carbon produced by CO2 of chicken waste

    Institute of Scientific and Technical Information of China (English)

    HUANG Yaji; JIN Baosheng; ZHONG Zhaoping; ZHONG Wenqi; XIAO Rui

    2008-01-01

    Preparation of activated carbon from chicken waste is a promising way to produce a useful adsorbent for Hg removal.A three-stage activation process (drying at 200℃,pyrolysis in N2 atmosphere,followed by CO2 activation) was used for the production of activated samples.The effects of carbonization temperature (400-600 ℃),activation temperature (700-900 ℃),and activation time (1-2.5 h) on the physicochemieal properties (weight-loss and BET surface) of the prepared carbon were investigated.Adsorptive removal of mercury from real flue gas onto activated carbon has been studied.The activated carbon from chicken waste has the same mercury capacity as commercial activated carbon (Darco LH) (HgV:38.7% vs.53.5%,HgO:50.5% vs.68.8%),although its surface area is around 10 times smaller,89.5 m2/g vs.862 m2/g.The low cost activated carbon can be produced from chicken waste,and the procedure is suitable.

  6. National Low-Level Waste Management Program Radionuclide Report Series

    Energy Technology Data Exchange (ETDEWEB)

    Rudin, M.J.; Garcia, R.S.

    1992-02-01

    This volume serves as an introduction to the National Low-Level Radioactive Waste Management Program Radionuclide Report Series. This report includes discussions of radionuclides listed in Title 10 of the Code of Federal Regulations Part 61.55, Tables 1 and 2 (including alpha-emitting transuranics with half-lives greater than five years). Each report includes information regarding radiological and chemical characteristics of specific radionuclides. Information is also included discussing waste streams and waste forms that may contain each radionuclide, and radionuclide behavior in the environment and in the human body. Not all radionuclides commonly found at low-level radioactive waste sites are included in this report. The discussion in this volume explains the rationale of the radionuclide selection process.

  7. Characteristics of PAHs adsorption in sewage treatment%城市污水中多环芳烃的吸附去除特性研究

    Institute of Scientific and Technical Information of China (English)

    范波; 王晓昌; 刘俊建

    2011-01-01

    Through a series of adsorption experiments, and by using quartz, kaolin, and natural clay as inorganic adsorbents and laboratory-cultured activated sludge as organic adsorbent for adsorbing model polycyclic aromatic hydrocarbons (PAHs) of NAPT, PHEN and PYR, this paper is aimed to find the characteristics of PAHs adsorption in the sewage treatment and analyze its main influential factors. Besides, we have also been trying to describe the inorganic suspended solids in sewage treatment by using the inorganic adsorbents and the activated sludge as adsorbent and adding NaN3 to suppress the interference of biodegradation process. The results of our experiments show that the power of adsorption of PAHs with the above said three inorganic adsorbents, whose order of adsorption can be seen as follows : natural clay > kaolin > quartz. The adsorption isotherms of the above mentioned three inorganic adsorbents tends to well follow the Langmuir isotherm, indicating a single-layer adsorption nature. As for the activated sludge, its adsorption isotherm reveals a multi-molecular-level adsorption nature well following the Freundlich isotherm. Furthermore, we have also found that the adsorption capacity of the activated sludge for PAHs turns to be higher than that of the inorganic particles. Moreover, for all the absorbents with no exception , the adsorption capabilities are all closely related to the octanol/ water partition coefficient of the PAHs, which was found to be ordered as: PYR > PHEN > NAPT. In addition, we have also investigated the effects of temperature, pH, and the competitive adsorption properties between the different PAHs. The results of our investigation help us to conclude that the adsorption capacity of NAPT by kaolin turns to be falling with the temperature rising (10 ℃, 25 ℃, 30 ℃), an exothermic reaction feature, as it were named. However, while the adsorption process of activated sludge turns to be at odds, it reveals an endothermic reaction

  8. Cadmium-109 Radioisotope Adsorption onto Polypyrrole Coated Sawdust of Dryobalanops aromatic: Kinetics and Adsorption Isotherms Modelling

    Science.gov (United States)

    Olatunji, Michael Adekunle; Khandaker, Mayeen Uddin; Amin, Yusoff Mohd; Mahmud, Habibun Nabi Muhammad Ekramul

    2016-01-01

    A radiotracer study was conducted to investigate the removal characteristics of cadmium (109Cd) from aqueous solution by polypyrrole/ sawdust composite. Several factors such as solution pH, sorbent dosage, initial concentration, contact time, temperature and interfering metal ions were found to have influence on the adsorption process. The kinetics of adsorption was relatively fast, reaching equilibrium within 3 hours. A lowering of the solution pH reduced the removal efficiency from 99.3 to ~ 46.7% and an ambient temperature of 25°C was found to be optimum for maximum adsorption. The presence of sodium and potassium ions inhibited 109Cd removal from its aqueous solution. The experimental data for 109Cd adsorption showed a very good agreement with the Langmuir isotherm and a pseudo-first order kinetic model. The surface condition of the adsorbent before and after cadmium loading was investigated using BET, FESEM and FTIR. Considering the low cost of the precursor’s materials and the toxicity of 109Cd radioactive metal, polypyrrole synthesized on the sawdust of Dryobalanops aromatic could be used as an efficient adsorbent for the removal of 109Cd radioisotope from radionuclide-containing effluents. PMID:27706232

  9. Corrosion inhibition and adsorption characteristics of Tridax Procumbens L leaves extract on mild steel immersed in 1M HCl solution

    Directory of Open Access Journals (Sweden)

    Kenneth Kanayo ALANEME

    2016-12-01

    Full Text Available The corrosion inhibition and adsorption mechanism of Tridax procumbens Linn leaves extract on mild steel immersed in 1M HCl solution was investigated. Mass loss, corrosion rate and inhibition efficiency from gravimetric and potentiodynamic polarization measurements, atomic adsorption spectroscopy (AAS, Fourier transform infra red spectroscopy (FTIR, and scanning electron microscopy; were used for the analysis. The results show that within the selected range of concentration of the extract and corrosion test temperatures, the inhibition efficiency obtained was within the range of 81 and 96 %. The efficiency values were observed to increase with increase in the extract concentration but decreased slightly with increase in temperature. The inhibitor molecules were noted to be physically adsorbed on the mild steel surface with OH, NH, and CO groups confirmed as the active phytochemical constituents in the extract responsible for the adsorption. The adsorption process fitted perfectly with the Langmuir adsorption isotherm indicating that the extract was strongly adsorbed on the mild steel surface.

  10. Interaction Between Charge Characteristics and Cu2+ Adsorption-Desorption of Soils with Variable or Permanent Charge

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Charge characteristics and Cu2+ adsorption-desorption of soils with variable charge (latosol) and per-manent charge (brown soil) and the relationship between them were studied by means of back-titration andadsorption equilibrium respectively. The amount of variable negative charge was much less in variable-chargesoil than in permanent-charge soil and increased with the pH in the system, but the opposite trend occurredin the points of zero charge (PZCs). The amount of Cu2+ ions sorbed by permanent-charge soil was morethan that by variable-charge soil and increased with the increase of Cu2+ concentration within a certainrange in the equilibrium solution. The amount of Cu2+ ions desorbed with KCl from permanent-chargesoil was more than that from variable-charge soil, but the amount of Cu2+ ions desorbed with de-ionizedwater from permanent-charge soil was extremely low whereas there was still a certain amount of desorptionfrom variable-charge soil. The increase of PZC of soils with variable or permanent charge varied with theincrement of Cu2+ ions added. When the same amount of Cu2+ ions was added, the increments of PZC andvariable negative surface charge of permanent-charge soil were different from those of variable-charge soil.

  11. Radionuclides in US coals

    Energy Technology Data Exchange (ETDEWEB)

    Bisselle, C. A.; Brown, R. D.

    1984-03-01

    The current state of knowledge with respect to radionuclide concentrations in US coals is discussed. Emphasis is placed on the levels of uranium in coal (and lignite) which are considered to represent a concern resulting from coal combustion; areas of the US where such levels have been found; and possible origins of high radionuclide levels in coal. The report reviews relevant studies and presents new data derived from a computerized search of radionuclide content in about 4000 coal samples collected throughout the coterminous US. 103 references, 5 figures, 5 tables.

  12. Adsorption characteristics of sulfur powder by bamboo charcoal to restrain sulfur allergies.

    Science.gov (United States)

    Peng, Wanxi; Ge, Shengbo; Liu, Zhenling; Furuta, Yuzo

    2017-01-01

    Exposures to particulate matter with a diameter of 2.5 μm or less (PM2.5) may influence the risk of birth defects and make you allergic, which causes serious harm to human health. Bamboo charcoal can adsorb harmful substances,that was of benefitto people's health. In order to figure out the optimal adsorbtion condition and the intrinsic change of bamboo charcoal, five chemicals were adsorbed by bamboo charcoal and were analyzed by FT-IR. The optimal blast time was 80 min of Na2SO3, 100 min of Na2S2O8, 20 min of Na2SO4, 120 min of Fe2(SO4)3 and 60 min or 100 min of S. FT-IR spectra showed that bamboo charcoal had five characteristic peaks of S-S stretch, H2O stretch, O-H stretch, C 000000000000 000000000000 000000000000 111111111111 000000000000 111111111111 000000000000 000000000000 000000000000 O stretch or CC stretch, and NO2 stretch at 3850 cm(-1), 3740 cm(-1), 3430 cm(-1), 1630 cm(-1) and 1530 cm(-1), respectively. For Na2SO3, the peaks at 3850 cm(-1), 3740 cm(-1), 3430 cm(-1), 1630 cm(-1) and 1530 cm(-1) achieved the maximum at 20 min. For Na2S2O8, the peaks at 3850 cm(-1), 3740 cm(-1), 3430 cm(-1) and 1530 cm(-1) achieved the maximum at 40 min. For Na2SO4, the peaks at 3850 cm(-1), 3740 cm(-1) and 1530 cm(-1) achieved the maximum at 40 min. For Fe2(SO4)3, the peaks at 3850 cm(-1), 3740 cm(-1), 1630 cm(-1) and 1530 cm(-1) achieved the maximum at 120 min. For S, the peaks at 3850 cm(-1) and 3740 cm(-1) achieved the maximum at 40 min, the peaks at 1630 cm(-1) and 1530 cm(-1) achieved the maximum at 40 min. It proved that bamboo charcoal could remove sulfur powder from air to restrain sulfur allergies.

  13. An eco-friendly dyeing of woolen yarn by Terminalia chebula extract with evaluations of kinetic and adsorption characteristics

    Science.gov (United States)

    Shabbir, Mohd; Rather, Luqman Jameel; Shahid-ul-Islam; Bukhari, Mohd Nadeem; Shahid, Mohd; Ali Khan, Mohd; Mohammad, Faqeer

    2016-01-01

    In the present study Terminalia chebula was used as an eco-friendly natural colorant for sustainable textile coloration of woolen yarn with primary emphasis on thermodynamic and kinetic adsorption aspects of dyeing processes. Polyphenols and ellagitannins are the main coloring components of the dye extract. Assessment of the effect of pH on dye adsorption showed an increase in adsorption capacity with decreasing pH. Effect of temperature on dye adsorption showed 80 °C as optimum temperature for wool dyeing with T. chebula dye extract. Two kinetic equations, namely pseudo first-order and pseudo second-order equations, were employed to investigate the adsorption rates. Pseudo second-order model provided the best fit (R2 = 0.9908) to the experimental data. The equilibrium adsorption data were fitted by Freundlich and Langmuir isotherm models. The adsorption behavior accorded well (R2 = 0.9937) with Langmuir isotherm model. Variety of eco-friendly and sustainable shades were developed in combination with small amount of metallic mordants and assessed in terms of colorimetric (CIEL∗a∗b∗ and K/S) properties measured using spectrophotometer under D65 illuminant (10° standard observer). The fastness properties of dyed woolen yarn against light, washing, dry and wet rubbing were also evaluated. PMID:27222752

  14. An eco-friendly dyeing of woolen yarn by Terminalia chebula extract with evaluations of kinetic and adsorption characteristics.

    Science.gov (United States)

    Shabbir, Mohd; Rather, Luqman Jameel; Shahid-Ul-Islam; Bukhari, Mohd Nadeem; Shahid, Mohd; Ali Khan, Mohd; Mohammad, Faqeer

    2016-05-01

    In the present study Terminalia chebula was used as an eco-friendly natural colorant for sustainable textile coloration of woolen yarn with primary emphasis on thermodynamic and kinetic adsorption aspects of dyeing processes. Polyphenols and ellagitannins are the main coloring components of the dye extract. Assessment of the effect of pH on dye adsorption showed an increase in adsorption capacity with decreasing pH. Effect of temperature on dye adsorption showed 80 °C as optimum temperature for wool dyeing with T. chebula dye extract. Two kinetic equations, namely pseudo first-order and pseudo second-order equations, were employed to investigate the adsorption rates. Pseudo second-order model provided the best fit (R (2) = 0.9908) to the experimental data. The equilibrium adsorption data were fitted by Freundlich and Langmuir isotherm models. The adsorption behavior accorded well (R (2) = 0.9937) with Langmuir isotherm model. Variety of eco-friendly and sustainable shades were developed in combination with small amount of metallic mordants and assessed in terms of colorimetric (CIEL(∗) a (∗) b (∗) and K/S) properties measured using spectrophotometer under D65 illuminant (10° standard observer). The fastness properties of dyed woolen yarn against light, washing, dry and wet rubbing were also evaluated.

  15. Characteristics of DNA adsorption on different sizes red soil colloidal particles%不同粒径红壤胶体颗粒对DNA的吸附特性

    Institute of Scientific and Technical Information of China (English)

    廖敏; 谢晓梅; 方舒; 裘晓白; 陈娜; 徐雅倩; 姜春燕; 陈雪芳

    2013-01-01

    By using balance reaction method, this paper studied the adsorption characteristics and thermodynamic properties of DNA on four kinds of red soil colloids (organic matter-contained coarse clay, organic matter-removed coarse clay, organic matter-contained fine clay, and organic matter-removed fine clay).The DNA adsorption on the four red soil colloids was a process of fast reaction, and the adsorption isotherms were conformed to the Langmuir equation, with the corresponding correlation coefficient (r2) being 0.974, 0.991, 0.958, and 0.975 , respectively.The maximum adsorption amount of DNA on the colloidal particles followed the order of organic matter-contained fine clay > organic matter-removed fine clay > organic matter-contained coarse clay > organic matter-removed coarse clay, implying that the size and organic matter content of colloidal particles played an important role in DNA adsorption.Electrolyte concentration and type and adsorption system pH were the main factors affecting the DNA adsorption on the four soil colloids.Within a definite electrolyte concentration range ( NaCl < 60 mmol·L-1 and CaCl2 < 10 mmol·L-1) , the adsorption amount of DNA on the red soil colloids increased significantly with the increase of electrolyte concentration.As compared with sodium ion, calcium ion had a greater promotion effect on the DNA adsorption, but the effect decreased significantly with the increase of adsorption system pH.The DNA adsorption on the organic matter-contained red soil colloids was an endothermic reaction, while the DNA adsorption on the organic matter-removed red soil colloids was an exothermic reaction.The DNA adsorption on the red soil colloids was a process of entropy increase.%采用平衡法研究了含有机质粗粘粒、去有机质粗粘粒、含有机质细粘粒和去有机质细粘粒4种红壤胶粒对DNA的吸附特征及其热力学特性.结果表明:4种红壤胶粒对DNA的吸附是快反应过程,Langmuir

  16. Gas adsorption and high-emission current induced degradation of field emission characteristics in solution-processed ZnO nanoneedles

    Science.gov (United States)

    Dardona, Sameh; Peles, Amra; Wrobel, Gregory; Piech, Martin; Gao, Pu-Xian

    2010-12-01

    The effects of gas adsorption and high current on the field emission characteristics of ZnO nanoneedles grown directly from metal electrodes have been systematically investigated. Exposure of nanoneedles to H2, N2, or O2 gas degraded the field emission characteristics, with O2 having the strongest impact. Complete recovery of emission current following H2 and N2 treatment was accomplished by vacuum annealing at 450 °C. Meanwhile, changes induced by O2 adsorption were irreversible. First-principle calculations revealed electronic structure modifications through change of work function and charge density distribution upon gas exposure. It is suggested that the emission current degradation originates from shifts in the Fermi level caused by charge transfer from nanoneedle surface to gas adsorbates. Moreover, field emission degradation has been observed at high currents as a result of surface melting at the nanoneedles apex caused by resistive heating.

  17. Adsorption characteristics of arsenic from micro-polluted water by an innovative coal-based mesoporous activated carbon.

    Science.gov (United States)

    Li, Wei-Guang; Gong, Xu-Jin; Wang, Ke; Zhang, Xin-Ran; Fan, Wen-Biao

    2014-08-01

    An innovative coal-based mesoporous activated carbon (NCPAC) was prepared by re-agglomeration, oxidation and two-step activation using coal-blending as precursor. Adsorption capacities of As(III) and As(V) ions (contents (15.26%). The adsorption capacities of NCPAC for As(III) and As(V) were found to be strongly dependent on pH and contact time. The optimal pH value was 6. The equilibrium time was 60min for adsorption of As(III) and As(V) by NCPAC. The Langmuir model fitted the experimental data well for both As(III) (R(2)=0.9980) and As(V) (R(2)=0.9988). Maximum adsorption capacities of As(III) and As(V) (C0=0.50mg/L) by NCPAC were 1.491 and 1.760mg/g, respectively.

  18. Adsorption characteristics of UO(2)(2+) and Th(4+) ions from simulated radioactive solutions onto chitosan/clinoptilolite sorbents.

    Science.gov (United States)

    Humelnicu, Doina; Dinu, Maria Valentina; Drăgan, Ecaterina Stela

    2011-01-15

    Adsorption features of UO(2)(2+) and Th(4+) ions from simulated radioactive solutions onto a novel chitosan/clinoptilolite (CS/CPL) composite as beads have been investigated compared with chitosan cross-linked with epichlorohydrin. The effects of contact time, the initial metal ion concentration, sorbent mass and temperature on the adsorption capacity of the CS-based sorbents were investigated. The adsorption kinetics was well described by the pseudo-second order equation, and the adsorption isotherms were better fitted by the Sips model. The maximum experimental adsorption capacities were 328.32 mg Th(4+)/g composite, and 408.62 mg UO(2)(2+)/g composite. The overall adsorption tendency of CS/CPL composite toward UO(2)(2+) and Th(4+) radiocations in the presence of Cu(2+), Fe(2+) and Al(3+), under competitive conditions, followed the order: Cu(2+)>UO(2)(2+)>Fe(2+)>Al(3+), and Cu(2+)>Th(4+)>Fe(2+)>Al(3+), respectively. The negative values of Gibbs free energy of adsorption indicated the spontaneity of the adsorption of radioactive ions on both the CS/CPL composite and the cross-linked CS. The desorption level of UO(2)(2+) from the composite CS/CPL, by using 0.1M Na(2)CO(3), was around 92%, and that of Th(4+) ions, performed by 0.1M HCl, was around 85%, both values being higher than the desorption level of radiocations from the cross-linked CS, which were 89% and 83%, respectively.

  19. Study on Phosphorus Adsorption Characteristics of Different Substrates in Constructed Wetlands%不同人工湿地基质对磷的吸附特性研究

    Institute of Scientific and Technical Information of China (English)

    刘培; 赵业稼; 王香香; 嵇祎慧

    2012-01-01

    The characteristics of phosphorus adsorption by limestone, Zeolite, fly ash and cinder were studied. The results showed that: the Langmuir equation , could better describe the phosphorus adsorption by fly ash, zeolite and limestone; while the Fruendlich equation could better describe the phosphorus adsorption by cinder; the order of the phosphorus adsorption was as follows: cinder 〉 fly ash 〉 zeolit 〉 limestone.%以石灰石、沸石、粉煤灰和煤渣四种人工湿圭电基质为研究对象,研究了其对磷的吸附特性。结果表明:粉煤灰、沸石和石灰石对磷的吸附用Langmuir吸附等温方程描述较好;而煤渣对磷的吸附用Freundlich吸附等温方程描述较好;四种基质对磷吸附能力大小为:煤渣〉粉煤灰〉沸石〉石灰石。

  20. ACCUMULATION OF 134CS IN THE PEPPER DEPENDING ON SOIL CHARACTERISTICS AND METHODS FOR REDUCTION OF THE TRANSFER OF RADIONUCLIDES FROM THE SOIL INTO THE VEGETATION PRODUCTION

    Directory of Open Access Journals (Sweden)

    D STANEVA

    2007-04-01

    Full Text Available The particularities of the soil as sorbent, its complex composition and the differences in its properties impose the research of the accumulation of the The development of methods for reduction of the transfer of radionuclides from the soil into the vegetation production being of particular signifi cance for the implementation agricultural activities in conditions of radioactive pollution of the soil, the impact of potassium, calcium and EDTA or ethylenediaminetetraac etic acid over the accumulation of radio-caesium from the soil into the plants. As it is seen from the results presented, the input of potassium, calcium and EDTA in the Orthic Luvisols signifi cantly decreased the input of Сs-134 into the pepper plants.

  1. Sediment and radionuclide transport in rivers: radionuclide transport modeling for Cattaraugus and Buttermilk Creeks, New York

    Energy Technology Data Exchange (ETDEWEB)

    Onishi, Y.; Yabusaki, S.B.; Kincaid, C.T.; Skaggs, R.L.; Walters, W.H.

    1982-12-01

    SERATRA, a transient, two-dimensional (laterally-averaged) computer model of sediment-contaminant transport in rivers, satisfactorily resolved the distribution of sediment and radionuclide concentrations in the Cattaraugus Creek stream system in New York. By modeling the physical processes of advection, diffusion, erosion, deposition, and bed armoring, SERATRA routed three sediment size fractions, including cohesive soils, to simulate three dynamic flow events. In conjunction with the sediment transport, SERATRA computed radionuclide levels in dissolved, suspended sediment, and bed sediment forms for four radionuclides (/sup 137/Cs, /sup 90/Sr, /sup 239/ /sup 240/Pu, and /sup 3/H). By accounting for time-dependent sediment-radionuclide interaction in the water column and bed, SERATA is a physically explicit model of radionuclide fate and migration. Sediment and radionuclide concentrations calculated by SERATA in the Cattaraugus Creek stream system are in reasonable agreement with measured values. SERATRA is in the field performance phase of an extensive testing program designed to establish the utility of the model as a site assessment tool. The model handles not only radionuclides but other contaminants such as pesticides, heavy metals and other toxic chemicals. Now that the model has been applied to four field sites, including the latest study of the Cattaraugus Creek stream system, it is recommended that a final model be validated through comparison of predicted results with field data from a carefully controlled tracer test at a field site. It is also recommended that a detailed laboratory flume be tested to study cohesive sediment transport, deposition, and erosion characteristics. The lack of current understanding of these characteristics is one of the weakest areas hindering the accurate assessment of the migration of radionuclides sorbed by fine sediments of silt and clay.

  2. Selected radionuclides important to low-level radioactive waste management

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-11-01

    The purpose of this document is to provide information to state representatives and developers of low level radioactive waste (LLW) management facilities about the radiological, chemical, and physical characteristics of selected radionuclides and their behavior in the environment. Extensive surveys of available literature provided information for this report. Certain radionuclides may contribute significantly to the dose estimated during a radiological performance assessment analysis of an LLW disposal facility. Among these are the radionuclides listed in Title 10 of the Code of Federal Regulations Part 61.55, Tables 1 and 2 (including alpha emitting transuranics with half-lives greater than 5 years). This report discusses these radionuclides and other radionuclides that may be significant during a radiological performance assessment analysis of an LLW disposal facility. This report not only includes essential information on each radionuclide, but also incorporates waste and disposal information on the radionuclide, and behavior of the radionuclide in the environment and in the human body. Radionuclides addressed in this document include technetium-99, carbon-14, iodine-129, tritium, cesium-137, strontium-90, nickel-59, plutonium-241, nickel-63, niobium-94, cobalt-60, curium -42, americium-241, uranium-238, and neptunium-237.

  3. Transuranic radionuclides dispersed into the aquatic environment, a bibliography

    Energy Technology Data Exchange (ETDEWEB)

    Noshkin, V.E.; Stoker, A.C.; Wong, Kai M. [and others

    1994-04-01

    The purpose of this project was to compile a bibliography of references containing environmental transuranic radionuclide data. Our intent was to identify those parameters affecting transuranic radionuclide transport that may be generic and those that may be dependent on chemical form and/or environmental conditions (i.e., site specific) in terrestrial, aquatic and atmospheric environments An understanding of the unique characteristics and similarities between source terms and environmental conditions relative to transuranic radionuclide transport and cycling will provide the ability to assess and predict the long term impact on man and the environment. An additional goal of our literature review, was to extract the ranges of environmental transuranic radionuclide data from the identified references for inclusion in a data base. Related to source term, these ranges of data can be used to calculate the dose to man from the radionuclides, and to perform uncertainty analyses on these dose assessments. On the basis of our reviews, we have arbitrarily outlined five general source terms. These are fallout, fuel cycle waste, accidents, disposal sites and resuspension. Resuspension of the transuranic radionuclides is a unique source term, in that the radionuclides can originate from any of the other source terms. If these transuranic radionuclides become resuspended into the air, they then become important as a source of inhaled radionuclides.

  4. Adsorption characteristics of trace levels of bromate in drinking water by modified bamboo-based activated carbons.

    Science.gov (United States)

    Chen, Ho-Wen; Chuang, Yen Hsun; Hsu, Cheng-Feng; Huang, Winn-Jung

    2017-09-19

    This study was undertaken to investigate the adsorption kinetics and isotherms of bromate (BrO3(-)) on bamboo charcoals that are activated with nitrogen and water vapor. Bamboo-based activated carbon (AC) was dipped in acid and oxidized in a mixture of potassium permanganate and sulfuric acid. Oxidation treatment considerably improved the physicochemical properties of AC, including purity, pore structure and surface nature, significantly enhancing BrO3(-) adsorption capacity. AC with many oxygenated groups and a high mesopore volume exhibited a particularly favorable tendency for BrO3(-) adsorption. Its adsorption of BrO3(-) is best fitted using Langmuir isotherm, and forms a monolayer. A kinetic investigation revealed that the adsorption of BrO3(-) by the ACs involved chemical sorption and was controlled by intra-particle diffusion. The competitive effects of natural organic matter (NOM) on AC were evaluated, and found to reduce the capacity of carbon to adsorb BrO3(-). Residual dissolved ozone reacted with AC, reducing its capacity to absorb BrO3(-). Proper dosing and staging of the ozonation processes can balance the ozone treatment efficiency, BrO3(-) formation, and the subsequent removal of BrO3(-).

  5. Adsorption characteristics of adsorbent resins and antioxidant capacity for enrichment of phenolics from two-phase olive waste.

    Science.gov (United States)

    Wang, Zhihong; Wang, Chengzhang; Yuan, Jiaojiao; Zhang, Changwei

    2017-01-01

    In this study, the adsorption properties of nine resins including polyamide resin (30-60), polyamide resin (60-100) AB-8, S-8, D-101, NKA-9, NKA-II, XDA-1 and XDA-4 for enrichment phenolics of the olive waste were investigated. XDA-1 and NKA-II were chosen for further study due to their outstanding adsorption and desorption capacity. XDA-1 and NKA-II had similar adsorption and desorption behaviors for phenolics of olive waste. The adsorption mechanism could be better explained by pseudo second-order kinetics model and Freundlich isotherm model, and the adsorption processes were spontaneously and exothermic. The experiment of gradient elution were carried out through treated XDA-1 resins column, the result indicated the total phenolics were mainly obtained from the 40% and 60% ethanol fraction. The order of antioxidant capacity by DPPH  , ABTS(+) radical and FRAP assay was similar with the content of phenolics from fraction elution. The compositions of phenolics from different elution fractions were determined by reversed phase-HPLC-DAD method. Gallic acid, hydroxytyrosol, tyrosol and ferulic acid were the major constituent in the fraction elute, and the content of hydroxytyrosol reached to the 41.69mg/g. The above results revealed the synergistic effects of the different phenolics contribute to the antioxidant capacity.

  6. Preparation and Characteristics of Activated Carbon from Wood Bark and Its Use for Adsorption of Cu (II

    Directory of Open Access Journals (Sweden)

    Jiahui ZHANG

    2014-12-01

    Full Text Available In this study, wood bark activated carbon (bark activated carbon, BAC were prepared by the method of steam activation at the activation temperature of 700 °C and 800 °C. The pore structures of BAC samples obtained were analysed via means of low temperature nitrogen adsorption. Iodine adsorption value and Cu (II ions adsorption capacity were also investigated. The results indicated that micropores and mesopores were abundant in BACs, which indicated a better adsorption effect in iodine and Cu (II ions adsorption capacities than wood bark carbon. The efficiency for the removal of Cu (II ions were carried out as a function of contact time. The optimal dosage of Cu (II ions by BAC700 and BAC800 samples is 5 g/L with an optimal time of 30 min. The kinetic studies of BACs revealed a better correlation with the Lagergren pseudo-second order model. DOI: http://dx.doi.org/10.5755/j01.ms.20.4.6400

  7. Adsorption characteristics of multiple microcystins and cylindrospermopsin on sediment: Implications for toxin monitoring and drinking water treatment.

    Science.gov (United States)

    Maghsoudi, Ehsan; Prévost, Michèle; Vo Duy, Sung; Sauvé, Sébastien; Dorner, Sarah

    2015-09-01

    Adsorption of mixtures of cyanotoxins onto sediment as a dominant mechanism in the elimination of cyanotoxins from the aqueous phase has not been extensively investigated. The aim of this study was to investigate adsorption and desorption behavior of six microcystins including microcystin (MC)-LR, RR, YR, LY, LW and LF and cylindrospermopsin (CYN) on natural sediment. Freundlich and Langmuir isotherms could be fitted for MC-LR, RR, YR and CYN. Sorption kinetics showed immediate rapid adsorption for all cyanotoxins: CYN, MCLW and MCLF were adsorbed 72.6%, 56.7% and 55.3% respectively within 2 h. Results of desorption experiments demonstrated that less than 9% of cyanotoxins desorbed from sediment within 96 h. Adsorption of cyanotoxins onto three fractionated sediments particles, clay-silt (<75 μm), find sand (75-315 μm) and coarse sand (315-2000 μm) demonstrated that adsorption capacity of coarse sand fraction for all the tested cyanotoxins was less than 4% of the clay-silt fraction. Results of this study revealed that there is a potential for cyanotoxins to accumulate in the sediments of lakes, as well as in drinking water treatment plants. Monitoring programs must consider cyanotoxins in the particulate phase to avoid largely underestimating toxin concentrations following their release from blooms.

  8. PATHWAY: a simulation model of radionuclide-transport through agricultural food chains

    Energy Technology Data Exchange (ETDEWEB)

    Kirchner, T.B.; Whicker, F.W.; Otis, M.D.

    1982-01-01

    PATHWAY simulates the transport of radionuclides from fallout through an agricultural ecosystem. The agro-ecosystem is subdivided into several land management units, each of which is used either for grazing animals, for growing hay, or for growing food crops. The model simulates the transport of radionuclides by both discrete events and continuous, time-dependent processes. The discrete events include tillage of soil, harvest and storage of crops,and deposition of fallout. The continuous processes include the transport of radionuclides due to resuspension, weathering, rain splash, percolation, leaching, adsorption and desorption of radionuclides in the soil, root uptake, foliar absorption, growth and senescence of vegetation, and the ingestion assimilation, and excretion of radionuclides by animals. Preliminary validation studies indicate that the model dynamics and simulated values of radionuclide concentrations in several agricultural products agree well with measured values when the model is driven with site specific data on deposition from world-wide fallout.

  9. An Investigation of the Adsorption Characteristics of 5'ATP and 5'AMP onto the Surface of Caso4 x 2H2O

    Science.gov (United States)

    Calderon, J.; Sweeney, M. A.

    1984-01-01

    A model has been proposed in which solid surfaces can act as a site for cataletic activity of condensation reactions for certain biomolecules. From this model, the adsorption characteristics of 5'ATP and 5'AMP onto the surface of CaSO4.2H2O was chosen for study. It has been proven that 5'ATP and 5'AMP do adsorb onto the surface of CaSO4. Studies were then made to determine the dependence of absorption versus time, concentration, ionic strength and pH. It was found that the adsorption of the nucleotides is highly pH dependent, primarily determined by the phosphate acid groups of the nucleic acid molecule. From this investigation, the data obtained is discussed in relation to the model for the prebiotic earth.

  10. Adsorption of di-2-pyridyl ketone salicyloylhydrazone on Amberlite XAD-2 and XAD-7 resins: characteristics and isotherms.

    Science.gov (United States)

    Freitas, P A M; Iha, K; Felinto, M C F C; Suárez-Iha, M E V

    2008-07-01

    The adsorption of DPKSH onto Amberlite XAD-2 (styrene resin) and XAD-7 (acrylic ester resin) has been investigated, at (25+/-1) degrees C and pH 4.7. The experimental equilibrium data were fitted to the Langmuir, Freundlich, and Dubinin-Radushkevich (D-R) models. These three models provide a very good fit for both resins and the respective constants KL, KF, and KDR were calculated. For the same DPKSH concentration interval, the minimum time of contact for adsorption maximum at XAD-7 was smaller than at XAD-2 and the maximum amount of DPKSH adsorbed per gram of XAD-2 is smaller than at XAD-7. The investigation indicates that the mean sorption energy (E) characterizes a physical adsorption and the surfaces of both resins are energetically heterogeneous. The constants obtained in these studied systems were correlated and compared with those obtained for the silica gel/DPKSH system.

  11. Distribution of radionuclides in bayer process

    Energy Technology Data Exchange (ETDEWEB)

    Cuccia, Valeria; Oliveira, Arno H. de [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Dept. de Engenharia Nuclear; Rocha, Zildete [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil). Servico de Quimica e Radioquimica], E-mail: rochaz@cdtn.br

    2007-07-01

    Natural occurring radionuclides are present in many natural resources. Human activities may enhance concentrations of radionuclides and/or enhance potential of exposure to naturally occurring radioactive material (NORM). The industrial residues containing radionuclides have been receiving a considerable global attention, because of the large amounts of NORM containing wastes and the potential long term risks of long-lived radionuclides. Included in this global concern, this work focuses on the characterization of radioactivity in bauxite and samples of intermediate phases of Bayer process for alumina production, including the end product - alumina - and its main residue - red mud. The analytical techniques used were gamma spectrometry (HPGe detector) and Neutron Activation Analysis. It was found that the bauxite is the major contributor to radioactivity in Bayer process. It has activities of 37+-12 Bq.kg{sup -1} for {sup 238}U and 154+-16 Bq.kg{sup -1} for {sup 232}Th. The intermediate phases and the end product do not carry significant activity, desirable characteristic from the health physics point of view. Sand and red mud carry most part of radionuclides, and the concentrations are higher in the red mud than in the sand. Thus, these solid residues present activities concentrations enhanced, when compared to bauxite. (author)

  12. Radionuclide therapy revisited

    Energy Technology Data Exchange (ETDEWEB)

    Hoefnagel, C.A. (Nederlands Kanker Inst., Amsterdam (Netherlands). Dept. of Nuclear Medicine)

    1991-06-01

    Apart from its use in endocrinology and rheumatology, therapeutic nuclear medicine is developing rapidly as an additional treatment modality in oncology. Many different specific tumour-seeking radiopharmaceuticals are being applied both for diagnostic scintigraphy and treatment, using multiple routes and mechanisms to target radionuclides at tumours. After a brief introduction of some basic principles of radionuclide targeting, the therapeutic radiopharmaceuticals available are reviewed according to the accumulation site in relation to the cell nucleus; the results of their current clinical use for therapy are also reviewed. The response observed to a number of these applications, the non-invasiveness of the procedure and the relative lack of toxicity and late effects in comparison with chemotherapy and external beam radiotherapy make radionuclide therapy an attractive and realistic alternative in the management of malignant disease, as well as in the treatment of a few benign disorders. (orig.).

  13. Radionuclides in house dust

    CERN Document Server

    Fry, F A; Green, N; Hammond, D J

    1985-01-01

    Discharges of radionuclides from the British Nuclear Fuel plc (BNFL) reprocessing plant at Sellafield in Cumbria have led to elevated concentrations radionuclides in the local environment. The major routes of exposure of the public are kept under review by the appropriate Government departments and monitoring is carried out both by the departments and by BNFL itself. Recently, there has been increasing public concern about general environmental contamination resulting from the discharges and, in particular, about possible exposure of members of the public by routes not previously investigated in detail. One such postulated route of exposure that has attracted the interest of the public, the press and Parliament arises from the presence of radionuclides within houses. In view of this obvious and widespread concern, the Board has undertaken a sampling programme in a few communities in Cumbria to assess the radiological significance of this source of exposure. From the results of our study, we conclude that, alt...

  14. Characteristic Features of Stone-Wales Defects in Single-Walled Carbon Nanotube; Adsorption, Dispersion, and Field Emission

    Directory of Open Access Journals (Sweden)

    Seungkwang Roh

    2010-01-01

    Full Text Available Adsorption behaviors of dodecanethiol (C12H25SH molecules are investigated on the surface of single-walled carbon nanotubes (SWCNTs with vibrational and X-ray photoelectron spectrometers. The active adsorption sites are proved as Stone-Wales (SW defects (5–7 ring defects. The SW defect-removed SWCNTs formed by reacting nanotubes with allyl acrylate molecules are compared with pristine SWCNTs in dispersion and field emission. The former shows higher dispersion and field emission than the latter.

  15. Targeted Radionuclide Therapy

    Directory of Open Access Journals (Sweden)

    David Cheng

    2011-10-01

    Full Text Available Targeted radiotherapy is an evolving and promising modality of cancer treatment. The killing of cancer cells is achieved with the use of biological vectors and appropriate radionuclides. Among the many advantages of this approach are its selectiveness in delivering the radiation to the target, relatively less severe and infrequent side effects, and the possibility of assessing the uptake by the tumor prior to the therapy. Several different radiopharmaceuticals are currently being used by various administration routes and targeting mechanisms. This article aims to briefly review the current status of targeted radiotherapy as well as to outline the advantages and disadvantages of radionuclides used for this purpose.

  16. Radionuclides in radiation-induced bystander effect; may it share in radionuclide therapy?

    Science.gov (United States)

    Widel, M

    2017-01-01

    For many years in radiobiology and radiotherapy predominated the conviction that cellular DNA is the main target for ionizing radiation, however, the view has changed in the past 20 years. Nowadays, it is assumed that not only directed (targeted) radiation effect, but also an indirect (non-targeted) effect may contribute to the result of radiation treatment. Non-targeted effect is relatively well recognized after external beam irradiation in vitro and in vivo, and comprises such phenomena like radiation-induced bystander effect (RIBE), genomic instability, adaptive response and abscopal (out of field) effect. These stress-induced and molecular signaling mediated phenomena appear in non-targeted cells as variety responses resembling that observed in directly hit cells. Bystander effects can be both detrimental and beneficial in dependence on dose, dose-rate, cell type, genetic status and experimental condition. Less is known about radionuclide-induced non-targeted effects in radionuclide therapy, although, based on characteristics of the radionuclide radiation, on experiments in vitro utilizing classical and 3-D cell cultures, and preclinical study on animals it seems obvious that exposure to radionuclide is accompanied by various bystander effects, mostly damaging, less often protective. This review summarizes existing data on radionuclide induced bystander effects comprising radionuclides emitting beta- and alpha-particles and Auger electrons used in tumor radiotherapy and diagnostics. So far, separation of the direct effect of radionuclide decay from crossfire and bystander effects in clinical targeted radionuclide therapy is impossible because of the lack of methods to assess whether, and to what extent bystander effect is involved in human organism. Considerations on this topic are also included.

  17. Distribution and migration of long lived radionuclides in the environment around the Chernobyl Nuclear Power Plant

    Energy Technology Data Exchange (ETDEWEB)

    Amano, Hikaru; Matsunaga, Takeshi; Ueno, Takashi; Nagao, Seiya; Yanase, Nobuyuki; Watanabe, Miki; Hanzawa, Yukiko [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1999-03-01

    Characteristics of the distribution and migration of long lived radionuclides in the environment around the Chernobyl Nuclear Power Plant (30 km exclusion zone) has been investigated. Research items are, (i) Distribution of long lived radionuclides in the surface environment, (ii) Speciation of long lived radionuclides in the surface environment, (iii) Characteristics of the migration in the surface environment, (iv) Characteristics of the uptake into the vegetables, (v) Prediction of future radioecological situation in the environment, respectively. (author)

  18. Improvement of the antifouling characteristics in a bioreactor of polypropylene microporous membrane by the adsorption of Tween 20

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Surface modification by physical adsorption of Tween 20 was accomplished on polypropylene microporous membranes (PPMMs). Attenuated total reflection-Fourier transform infrared spectroscopy (ATR/FT-IR) and scanning electron microscope (SEM) were used to characterize the chemical and morphological changes on the membrane surfaces. Water contact angles and relative pure water fluxes were measured. The data showed that the hydrophilic performance for the modified membranes increased with the increase in the adsorption amount of Tween 20 onto the surface or into the pores of polypropylene microporous membranes. To test the antifouling property of the membranes by the adsorption of Tween 20 in a membrane bioreactor (MBR), filtration for active sludge was performed using synthetic wastewater. With the help of the data of water fluxes and the FE-SEM photos of the modified PPMMs before or after operating in a MBR for about 12 d, the PPMMs with monolayer adsorption of Tween 20 showed higher remained flux and stronger antifouling ability than unmodified membrane and other modification membranes studied.

  19. Adsorption and desorption characteristics of DNA onto the surface of amino functional mesoporous silica with various particle morphologies.

    Science.gov (United States)

    Hikosaka, Ryouichi; Nagata, Fukue; Tomita, Masahiro; Kato, Katsuya

    2016-04-01

    Recently, deoxyribonucleic acid (DNA) adsorption on solid materials has been reported for applications such as genetic diagnosis of diseases, gene delivery, and biosensors. Mesoporous silica (MPS) is an excellent carrier because of its high surface area and large pore volume. Functionalization of the MPS surface can be controlled by silane coupling reagents, and the MPS particle morphology can be easily changed by the synthetic conditions. In this study, to evaluate the ability of DNA adsorption on MPS, the MPS surface was functionalized using four reagents, 3-aminopropyltriethoxysilane (-NH2), N-(2-aminoethyl)-3-aminopropyltriethoxysilane (-2ENH2), N-(6-aminohexyl)aminopropyltrimethoxysilane (-2HNH2), and (3-trimethoxysilylpropyl)diethylenetriamine (-3NH2), each having a different number of amino groups and alkyl chain lengths. Moreover, we prepared three types of MPSs with different particle morphologies: sheet-type structure (MPS sheet), spherical MPS (MCM-41s), and nonporous spherical silica. A high adsorption capacity was observed in MPS sheets with -2HNH2 (sheet-2HNH2) and -3NH2 (sheet-3NH2), as well as MCM-41s with -3NH2 (41s-3NH2). The adsorption and desorption rates of DNA on these three MPSs were then examined and the best results were obtained with 41s-3NH2. These results demonstrate that the amino functionalized MPS materials are useful DNA adsorbents.

  20. Uniform surface modification of diatomaceous earth with amorphous manganese oxide and its adsorption characteristics for lead ions

    Energy Technology Data Exchange (ETDEWEB)

    Li, Song; Li, Duanyang; Su, Fei; Ren, Yuping; Qin, Gaowu, E-mail: lis@atm.neu.edu.cn

    2014-10-30

    Graphical abstract: - Highlights: • A uniform MnO{sub 2} layer was anchored onto diatomite surface. • Kinetics and isotherms over MnO{sub 2} modified diatomite were studied. • The Pb(II) adsorption is based on ion-exchange mechanism. - Abstract: A novel method to produce composite sorbent material compromising porous diatomaceous earth (DE) and surface functionalized amorphous MnO{sub 2} is reported. Via a simple in situ redox reaction over the carbonized DE powders, a uniform layer of amorphous MnO{sub 2} was anchored onto the DE surface. The hybrid adsorbent was characterized by X-ray diffraction, scanning electron microscopy, and infrared spectroscopy. The batch method has been employed to investigate the effects of surface coating on adsorption performance of DE. According to the equilibrium studies, the adsorption capacity of DE for adsorbing lead ions after MnO{sub 2} modification increased more than six times. And the adsorption of Pb{sup 2+} on the MnO{sub 2} surface is based on ion-exchange mechanism. The developed strategy presents a novel opportunity to prepare composite adsorbent materials by integrating nanocrystals with porous matrix.

  1. Quantitative modeling of Cerenkov light production efficiency from medical radionuclides.

    Science.gov (United States)

    Beattie, Bradley J; Thorek, Daniel L J; Schmidtlein, Charles R; Pentlow, Keith S; Humm, John L; Hielscher, Andreas H

    2012-01-01

    There has been recent and growing interest in applying Cerenkov radiation (CR) for biological applications. Knowledge of the production efficiency and other characteristics of the CR produced by various radionuclides would help in accessing the feasibility of proposed applications and guide the choice of radionuclides. To generate this information we developed models of CR production efficiency based on the Frank-Tamm equation and models of CR distribution based on Monte-Carlo simulations of photon and β particle transport. All models were validated against direct measurements using multiple radionuclides and then applied to a number of radionuclides commonly used in biomedical applications. We show that two radionuclides, Ac-225 and In-111, which have been reported to produce CR in water, do not in fact produce CR directly. We also propose a simple means of using this information to calibrate high sensitivity luminescence imaging systems and show evidence suggesting that this calibration may be more accurate than methods in routine current use.

  2. Adsorption Characteristics of Copper in Water Solution onto Zeolite%沸石粉对溶液中铜的吸附性能研究

    Institute of Scientific and Technical Information of China (English)

    李见云; 郑宾国; 化全县; 刘军坛; 冉桂花

    2011-01-01

    沸石粉是广泛用来控制和修复重金属污染土壤的无机材料,为了探究沸石钝化重金属Cu2+的作用机理,笔者通过批次振荡试验研究了沸石粉吸附溶液中Cu2+的热力学和动力学过程.结果表明,等温吸附过程极显著遵循Langmuir和Freundlich方程,沸石粉中Cu2+的最大吸附容量为3.839 g/kg,为优惠型吸附.吸附动力学极显著符合Lagergren准二级、EloVich和双常数方程,为快速吸附过程,吸附速率主控步骤为液膜扩散.△G<0,△H>0,△S>0,表明沸石吸附溶液中Cu2+的过程为自发吸热熵推动反应.%Zeolite is an extensively used inorganic material for control and remediation of heavy metal contaminated soil.In order to explore the passivation mechanism of Cu2+ by zeolite, the batch experiments were conducted to investigate adsorption thermodynamics and kinetics characteristics of Cu2+ in water solution onto zeolite.Results showed adsorption equilibrium data were well significantly fitted by Langmuir and Freundlich isotherms, and the process belonged to favorable adsorption.The theoretical saturated capacity was 3.839 g/kg.Lagergren' s pseudo-second-order, Elovich and two-constant kinetic models were found to best represent the adsorption data, which was a rapid adsorption process.Kinetic analysis demonstrated the film liquid diffusion process was the essential rate-controlling step.Positive Δ H, Δ S and negative Δ G indicated the adsorption was spontaneous, endothermic and entropy driven.

  3. Influence of pyrolysis temperature on characteristics and heavy metal adsorptive performance of biochar derived from municipal sewage sludge.

    Science.gov (United States)

    Chen, Tan; Zhang, Yaxin; Wang, Hongtao; Lu, Wenjing; Zhou, Zeyu; Zhang, Yuancheng; Ren, Lulu

    2014-07-01

    To investigate systematically the influence of pyrolysis temperature on properties and heavy metal adsorption potential of municipal sludge biochar, biophysical dried sludge was pyrolyzed under temperature varying from 500°C to 900°C. The biochar yield decreased with the increase in pyrolysis temperature, while the ash content retained mostly, thus transforming the biochars into alkaline. The structure became porous as the temperature increased, and the concentrations of surface functional group elements remained low. Despite the comparatively high content of heavy metal in the biochar, the leaching toxicity of biochars was no more than 20% of the Chinese standard. In the batch experiments of cadmium(II) adsorption, the removal capacity of biochars improved under higher temperature, especially at 800°C and 900°C even one order of magnitude higher than that of the commercial activated carbon. For both energy recovery and heavy metal removal, the optimal pyrolysis temperature is 900°C.

  4. Growth of 2D sheets of a MOF on graphene surfaces to yield composites with novel gas adsorption characteristics.

    Science.gov (United States)

    Kumar, Ram; Jayaramulu, Kolleboyina; Maji, Tapas Kumar; Rao, C N R

    2014-05-28

    Homogeneous graphene-MOF composites based on a 2D pillared-bilayer MOF (Cd-PBM), {[Cd4(azpy)2(pyrdc)4(H2O)2]·9H2O}n (azpy = 4,4'-azopyridine, pyrdc = pyridine-2,3-dicarboxylate), have been synthesized, using both graphene oxide (GO) and benzoic acid functionalized graphene (BFG). The composites GO@Cd-PBM and BFG@Cd-PBM demonstrate growth of the 2D nano-sheets of MOF on the graphene surface. While the pristine MOF, Cd-PBM shows selective CO2 uptake with a single-step type-I adsorption profile, the composites show stepwise CO2 uptake with a large hysteresis. With H2O and MeOH, on the other hand, the composites show a single-step adsorption unlike the parent MOF.

  5. An electroanalytical approach for evaluation of biochar adsorption characteristics and its application for lead and cadmium determination.

    Science.gov (United States)

    Suguihiro, Talita Mayumi; de Oliveira, Paulo Roberto; de Rezende, Edivaltrys Inayve Pissinati; Mangrich, Antonio Sálvio; Marcolino, Luiz Humberto; Bergamini, Márcio F

    2013-09-01

    This work describes for first time the use of electroanalytical techniques for evaluation of adsorptive proprieties of biochar using it as electrode modifier and its application for preconcentration and determination of Lead(II) and Cadmium(II) under differential pulse adsorptive voltammetric conditions (DPAdSV). Samples of biochars were obtained from castor oil cake using a predefined set of experimental conditions varying the heating rate (V), final temperature (T) and warm-up period (P) and subsequently used for carbon paste modified electrode (CPME) preparation. The proposed method was applied for Lead(II) and Cadmium(II) determination in spiked simulated industrial effluents and the limit of detection obtained for both metals were adequated for determination of these evaluated ions taking into account the limits established by Brazilian legislation. For all samples analyzed, recoveries ranged from 95% to 104% were obtained and no significative interferences were observed for common cations in water samples.

  6. Adsorption characteristics of selected pharmaceuticals and an endocrine disrupting compound-Naproxen, carbamazepine and nonylphenol-on activated carbon.

    Science.gov (United States)

    Yu, Zirui; Peldszus, Sigrid; Huck, Peter M

    2008-06-01

    The adsorption of two representative pharmaceutically active compounds (PhACs) (naproxen and carbamazepine) and one endocrine disrupting compound (nonylphenol) were evaluated on two types of activated carbon. When determining their isotherms at environmentally relevant concentration levels, it was found that at this low concentration range (10-800 ng/L), removals of the target compounds were contrary to expectations based on their hydrophobicity. Nonylphenol (log K(ow) 5.8) was most poorly adsorbed, whereas carbamazepine (log K(ow) 2.45) was most adsorbable. Nonylphenol Freundlich isotherms at this very low concentration range had a much higher 1/n compared to isotherms at much higher concentrations. This indicates that extrapolation from an isotherm obtained at a high concentration range to predict the adsorption of nonylphenol at a concentration well below the range of the original isotherm, leads to a substantial overestimation of its removals. Comparison of isotherms for the target compounds to those for other conventional micropollutants suggested that naproxen and carbamazepine could be effectively removed by applying the same dosage utilized to remove odorous compounds (geosmin and MIB) at very low concentrations. The impact of competitive adsorption by background natural organic matter (NOM) on the adsorption of the target compounds was quantified by using the ideal adsorbed solution theory (IAST) in combination with the equivalent background compound (EBC) approach. The fulfilment of the requirements for applying the simplified IAST-EBC model, which leads to the conclusion that the percentage removal of the target compounds at a given carbon dosage is independent of the initial contaminant concentration, was confirmed for the situation examined in the paper. On this basis it is suggested that the estimated minimum carbon usage rates (CURs) to achieve 90% removal of these emerging contaminants would be valid at concentrations of less than 500 ng/L in

  7. Adsorption characteristics of graphene oxide as a solid adsorbent for aniline removal from aqueous solutions: Kinetics, thermodynamics and mechanism studies

    Directory of Open Access Journals (Sweden)

    Ali Fakhri

    2017-01-01

    Full Text Available The aim of this study is to investigate the possibility of graphene oxide (GO as an alternative adsorbent for aniline removal from aqueous solution. Adsorption properties of GO for aniline removal were regularly investigated, including pH effect, adsorbent dose, temperature, contact time and initial concentration. The adsorption amount of aniline decreased with increasing pH. The experimental data were evaluated by Langmuir, Freundlich, Temkin and Harkins–Jura models in order to describe the equilibrium isotherms. Equilibrium data fitted well to the Langmuir model. The kinetic parameters achieved at different concentrations were analyzed using a pseudo first-order, pseudo second-order kinetic equation and intra-particle diffusion model. The experimental data fitted very well the pseudo second-order kinetic model. Thermodynamic parameters (free energy change, enthalpy change, and entropy change announced that the removal of aniline from GO was endothermic and spontaneous. The study showed that GO could be used as an efficient adsorbent material for the adsorption of aniline from aqueous solution.

  8. EBS Radionuclide Transport Abstraction

    Energy Technology Data Exchange (ETDEWEB)

    J. Prouty

    2006-07-14

    The purpose of this report is to develop and analyze the engineered barrier system (EBS) radionuclide transport abstraction model, consistent with Level I and Level II model validation, as identified in Technical Work Plan for: Near-Field Environment and Transport: Engineered Barrier System: Radionuclide Transport Abstraction Model Report Integration (BSC 2005 [DIRS 173617]). The EBS radionuclide transport abstraction (or EBS RT Abstraction) is the conceptual model used in the total system performance assessment (TSPA) to determine the rate of radionuclide releases from the EBS to the unsaturated zone (UZ). The EBS RT Abstraction conceptual model consists of two main components: a flow model and a transport model. Both models are developed mathematically from first principles in order to show explicitly what assumptions, simplifications, and approximations are incorporated into the models used in the TSPA. The flow model defines the pathways for water flow in the EBS and specifies how the flow rate is computed in each pathway. Input to this model includes the seepage flux into a drift. The seepage flux is potentially split by the drip shield, with some (or all) of the flux being diverted by the drip shield and some passing through breaches in the drip shield that might result from corrosion or seismic damage. The flux through drip shield breaches is potentially split by the waste package, with some (or all) of the flux being diverted by the waste package and some passing through waste package breaches that might result from corrosion or seismic damage. Neither the drip shield nor the waste package survives an igneous intrusion, so the flux splitting submodel is not used in the igneous scenario class. The flow model is validated in an independent model validation technical review. The drip shield and waste package flux splitting algorithms are developed and validated using experimental data. The transport model considers advective transport and diffusive transport

  9. EBS Radionuclide Transport Abstraction

    Energy Technology Data Exchange (ETDEWEB)

    R. Schreiner

    2001-06-27

    The purpose of this work is to develop the Engineered Barrier System (EBS) radionuclide transport abstraction model, as directed by a written development plan (CRWMS M&O 1999a). This abstraction is the conceptual model that will be used to determine the rate of release of radionuclides from the EBS to the unsaturated zone (UZ) in the total system performance assessment-license application (TSPA-LA). In particular, this model will be used to quantify the time-dependent radionuclide releases from a failed waste package (WP) and their subsequent transport through the EBS to the emplacement drift wall/UZ interface. The development of this conceptual model will allow Performance Assessment Operations (PAO) and its Engineered Barrier Performance Department to provide a more detailed and complete EBS flow and transport abstraction. The results from this conceptual model will allow PA0 to address portions of the key technical issues (KTIs) presented in three NRC Issue Resolution Status Reports (IRSRs): (1) the Evolution of the Near-Field Environment (ENFE), Revision 2 (NRC 1999a), (2) the Container Life and Source Term (CLST), Revision 2 (NRC 1999b), and (3) the Thermal Effects on Flow (TEF), Revision 1 (NRC 1998). The conceptual model for flow and transport in the EBS will be referred to as the ''EBS RT Abstraction'' in this analysis/modeling report (AMR). The scope of this abstraction and report is limited to flow and transport processes. More specifically, this AMR does not discuss elements of the TSPA-SR and TSPA-LA that relate to the EBS but are discussed in other AMRs. These elements include corrosion processes, radionuclide solubility limits, waste form dissolution rates and concentrations of colloidal particles that are generally represented as boundary conditions or input parameters for the EBS RT Abstraction. In effect, this AMR provides the algorithms for transporting radionuclides using the flow geometry and radionuclide concentrations

  10. 红壤中低分子量有机酸的吸附特征%Adsorption Characteristics of Low Molecular Weight Organic Acids in Red Soil

    Institute of Scientific and Technical Information of China (English)

    喻艳红; 李清曼; 张桃林; 王兴祥

    2011-01-01

    应用平衡法研究了红壤对草酸、柠檬酸、酒石酸和苹果酸的吸附行为.结果表明:红壤对有机酸的吸附量随着有机酸平衡溶液浓度的增加而增加,有机酸种类不同,吸附量也不同.有机酸在红壤中的吸附行为均可以很好地用Langrnuir、Freundlich和Temkim方程描述,其中以Langmnuir方程的拟合效果最好.红壤对有机酸均具有较高的吸附率,在0.5~20mmol L-1初始浓度范嗣内,草酸、柠檬酸、酒石酸和苹果酸的吸附率最大分别可达89.2%、77.5%、67.4%和47.1%.红壤对柠檬酸、酒石酸和苹果酸的吸附率均随着有机酸初始浓度的增加先急剧下降(<5 mmol L-1),之后缓慢下降至趋于平稳;草酸的吸附率则随着初始浓度的增加而增加,在3 mmol L-1左右时达到最大,随后降低至趋于平稳.%This research investigated the adsorption behaviours of oxalic, citric, tartaric and malic acids in red soil by a batch equilibrium method. The results indicated that the adsorption amount increased with the increase of equilibrium concentration, and the adsorption amount was different with the different type of organic acids. The adsorption characteristics of oxalic, citric, tartaric and malic all could be well described by Langmuir, Freundlich and Temkim equations, and the Langmuir equation was the best one. The adsorption ratios of organic acids in red soil were all high. When the initial concentrations ranged from 0.5 to 20 mmol L-1, the maximum adsorption ratio of oxalic,citric, tartaric and malic acids could reach 89.2%, 77.5%, 67.4% and 47.1%, respectively. The adsorption ratios of citric, tartaric and malic acids in red soil all dramatically decreased with the increasing initial concentrations of organic acids (< 5 mmol L-1), and then decreased slowly to be steady with the further increase of initial concentrations. The adsorption ratio of oxalic acid increased first with the increase of its initial concentration and

  11. Radionuclide diagnosis of allograft rejection

    Energy Technology Data Exchange (ETDEWEB)

    George, E.A.

    1982-10-01

    Interaction with one or more anatomical and physiopathological characteristics of the rejecting renal allograft is suggested by those radioagents utilized specifically for the diagnosis of allograft rejection. Rejection, the most common cause of declining allograft function, is frequently mimicked clinically or masked by other immediate or long term post transplant complications. Understanding of the anatomical pathological features and kinetics of rejection and their modification by immunosuppressive maintenance and therapy are important for the proper clinical utilization of these radioagents. Furthermore, in selecting these radionuclides, one has to consider the comparative availability, preparatory and procedural simplicity, acquisition and display techniques and the possibility of timely report. The clinical utilities of radiofibrinogen, /sup 99m/Tc sulfur colloid and /sup 67/Ga in the diagnosis of allograft rejection have been evaluated to a variable extent in the past. The potential usefulness of the recently developed preparations of /sup 111/In labeled autologous leukocytes and platelets are presently under investigation.

  12. Radionuclide transfer. Radionuklid Transfer

    Energy Technology Data Exchange (ETDEWEB)

    Gerber, G.B.

    1993-01-01

    The research project described here had the aim to obtain further information on the transfer of nuclides during pregnancy and lactation. The tests were carried out in mini-pigs and rats receiving unchanging doses of radionuclides with the food. The following findings were revealed for the elements examined: Fe, Se, Cs and Zn were characterized by very high transfer levels in the mother, infant and foetus. A substantial uptake by the mother alone was observed for Co, Ag and Mn. The uptake by the foetus and infant here was 1 to 10 times lower. A preferential concentration in certain tissues was seen for Sr and Tc; the thyroid levels of Tc were about equally high in mothers and infants, while Sr showed less accumulation in the maternal bone. The lanthanide group of substances (Ce, Eu and Gd as well as Y and Ru) were only taken up to a very limited extent. The uptake of the examined radionuclides (Fe, Co, Ag, Ce) with the food ingested was found here to be ten times greater in rats as compared to mini-pigs. This showed that great caution must be observed, if the behaviour of radionuclides in man is extrapolated from relevant data obtained in rodents. (orig./MG)

  13. Experimental study on dynamic gas adsorption

    Institute of Scientific and Technical Information of China (English)

    Qin Yueping; Wang Yaru; Yang Xiaobin; Liu Wei; Luo Wei

    2012-01-01

    In order to predict the actual adsorption amount as gas adsorption reaches the equilibrium,this research designed a dynamic gas adsorption experiment under constant temperature and pressure,and also studied the isopiestic adsorption characteristics of coal samples with same quality but different sizes.Through the experiment,the study found the adsorption-time changing relationships under different pressures of four different size samples.After regression analysis,we obtained the functional relationship between adsorption and time.According to this,the research resulted in the actual adsorption amount when gas adsorption reaches the equilibrium.In addition,the current study obtained the relationship between adsorption and pressure as well as the effect of the coal size to the adsorption rate.These results have great theoretical and practical significance for the prediction of gas amount in coal seam and gas adsorption process.

  14. 凹土-氯化钙复合吸附剂的制冷性能%Adsorption Refrigeration Characteristic of Attapulgite Based Calcium Chloride Composite Adsorbents

    Institute of Scientific and Technical Information of China (English)

    万意; 李全国; 芮正球; 崔群; 陈海军; 王海燕; 姚虎卿

    2012-01-01

    采用凹凸棒粘土和氯化钙为主要原料,用溶解-混合法制备了复合吸附剂;采用正压重量法测量了复合吸附剂对氨的吸附等温线;并测定了吸附剂-氨工质对的制冷特性.结果表明:吸附温度30℃下,复合吸附剂对氨的平衡吸附量为1.1 kg/kg,与氯化钙对氨的平衡吸附量相当.在装填密度为600kg/m3,吸附温度为30℃、蒸发压力为0.25MPa、解吸温度为300℃条件下,对氨的吸附量达到0.89~0.92kg/kg,循环吸附量为0.55~0.58kg/kg,是纯氯化钙的1.7倍:复合吸附剂-氨工质对制冷量可达761.84kJ/kg,比氯化钙-氨工质对提高了70%.而且,复合吸附剂具有良好的吸附解吸稳定性能.%The composite absorbent is mainly consisted of attapulgite and CaCI2as the resources, which were prepared by the dissolution-mixed method, and the content of attapulgite in composite absorbent is 10%. Adsorption isotherms of ammonia on absorbents were determined by positive gravimetric method. Adsorption-desorption cycle performance and cooling characteristics of composite absorbent -ammonia working pairs was evaluated by self-made adsorption-desorption measuring device. Experimental results show that the equilibrium capacity of ammonia on the composite absorbent is up to l.lkg/kg at 30℃, which is equal to that of CaCl2. The conditions of loading density 600kg/m3, adsorption temperature 30℃, ammonia evaporation pressure 0.25 MPa, desorption temperature 300℃, adsorption capacity of ammonia in the composite absorbent and its cyclic adsorption capacity is 0.89-0.92 kg/kg and 0.55~0.58 kg/kg, respectively, which is 1.7 times than that of CaCl2-ammonia working pairs. The cooling capacity is up to 761.84kJ/kg, which is increased by 70% compared to CaCl2/ ammonia. What's more, composite absorbent has excellent adsorption and desorption stability.

  15. Correlations between Photovoltaic Characteristics, Adsorption Number, and Regeneration Kinetics in Dye-Sensitized Solar Cells Revealed by Scanning Photocurrent Microscopy.

    Science.gov (United States)

    Mitsui, Masaaki; Kawano, Yuya; Mori, Kyosuke; Wakabayashi, Naoto

    2015-06-30

    Newly developed simultaneous scanning photocurrent and luminescence microscopy was applied to ruthenium-based dye-sensitized solar cells (DSCs) comprising a cover glass photoanode with a 100 nm thick TiO2 layer. Using this, we have investigated the lateral variations of several parameters of these DSCs under short-circuit conditions. Simultaneous measurement of photocurrent and luminescence images for the same area of the DSC demonstrated submicrometric lateral resolution of our photocurrent microscopy, which is approximately 10 times better than the resolution of photocurrent microscopy used in past studies. The photovoltaic parameters, such as short-circuit current density, open-circuit voltage, and charge-collection efficiency, were thus evaluated for local (or submicrometric) regions of the DSCs. Furthermore, the photocurrent saturation behavior of the DSCs was examined as a function of the excitation rate and analyzed on the basis of a three-state kinetic model. This protocol allowed for quantification of the dye-adsorption number and dye-regeneration rate constant for any local area of the DSCs. Consequently, the correlations between the dye adsorption number, photovoltaic parameters, and regeneration rate constant, which are difficult to address through examination of the entire cell, were revealed by the "zoom-in" approach utilizing this high-resolution photocurrent microscopy.

  16. Adsorption characteristics of humic acid-immobilized amine modified polyacrylamide/bentonite composite for cationic dyes in aqueous solutions

    Institute of Scientific and Technical Information of China (English)

    T. S. Anirudhan; P. S. Suchithra

    2009-01-01

    Humic acid-immobilized amine modified polyacrylamide/bentonite composite (HA-Am-PAA-B) was prepared and used as an adsorbent for the adsorption of cationic dyes (Malachite Green (MG), Methylene Blue (MB) and Crystal Violet (CV)) from aqueous solutions. The polyacrylamide/bentonite composite (PAA-B) was prepared by intercalative polymerization of acrylamide with Na-bentonite in the presence of N,N'-methylenebisacrylamide as a crosslinking agent and hexamethylenediammine as propagater. PAA-B was subsequently treated with ethylenediammine to increase its loading capacity for HA. The surface characterizations of the adsorbent were investigated. The adsorbent behaved like a cation exchanger and more than 99.0% removal of dyes was detected at pH range 6.0-8.0. The capacity of HA-Am-PAA-B was found to decrease in the following order: MG > MB > CV. The kinetic and isotherm data were interpreted by pseudo-second order rate equation and Freundlich isotherm model, respectively. Experiments were carried out using binary solute systems to assess the competitive adsorption phenomenon. The experimental isotherm data for each binary solute combination of MG, MB and CV were analyzed using Sheindrof-Rebhun-Sheintuch (SRS) (multicomponent Freundlich type) equation.

  17. Adsorption Characteristics of Cooling Tube with Exhausted Heat%余热冷管吸附特性研究

    Institute of Scientific and Technical Information of China (English)

    李玲超

    2015-01-01

    The solid adsorption refrigeration principle, introduces a waste heat as a heat source to heat absorption refrigeration tube. Design and introduces a new type of heat pipe cooling test device, using the device during opera-tion of the heat pipe cold experimental study. The results show that:in the adsorption of ambient temperature 12℃, set the desorption temperature of 180℃, heat the cold pipe cooling capacity alone 31kJ, cooling pipe lowest tem-perature reached 3℃, after the heat exchanger air temperature can reach 700 degrees Celsius.%根据固体吸附式制冷原理, 介绍了一种以余热为热源的余热吸附制冷管. 设计了一种新型的余热冷管测试装置, 采用该装置对余热冷管的运行过程进行实验研究. 实验结果表明: 在吸附环境温度为12℃, 设定脱附温度为180℃时, 余热冷管单只制冷量为31kJ, 制冷管最低温度达到3℃, 换热后空气温度可达到7℃.

  18. National Low-Level Waste Management Program Radionuclide Report Series. Volume 1, Introduction

    Energy Technology Data Exchange (ETDEWEB)

    Rudin, M.J.; Garcia, R.S.

    1992-02-01

    This volume serves as an introduction to the National Low-Level Radioactive Waste Management Program Radionuclide Report Series. This report includes discussions of radionuclides listed in Title 10 of the Code of Federal Regulations Part 61.55, Tables 1 and 2 (including alpha-emitting transuranics with half-lives greater than five years). Each report includes information regarding radiological and chemical characteristics of specific radionuclides. Information is also included discussing waste streams and waste forms that may contain each radionuclide, and radionuclide behavior in the environment and in the human body. Not all radionuclides commonly found at low-level radioactive waste sites are included in this report. The discussion in this volume explains the rationale of the radionuclide selection process.

  19. Therapeutic radionuclides in nuclear medicine: current and future prospects.

    Science.gov (United States)

    Yeong, Chai-Hong; Cheng, Mu-hua; Ng, Kwan-Hoong

    2014-10-01

    The potential use of radionuclides in therapy has been recognized for many decades. A number of radionuclides, such as iodine-131 ((131)I), phosphorous-32 ((32)P), strontium-90 ((90)Sr), and yttrium-90 ((90)Y), have been used successfully for the treatment of many benign and malignant disorders. Recently, the rapid growth of this branch of nuclear medicine has been stimulated by the introduction of a number of new radionuclides and radiopharmaceuticals for the treatment of metastatic bone pain and neuroendocrine and other malignant or non-malignant tumours. Today, the field of radionuclide therapy is enjoying an exciting phase and is poised for greater growth and development in the coming years. For example, in Asia, the high prevalence of thyroid and liver diseases has prompted many novel developments and clinical trials using targeted radionuclide therapy. This paper reviews the characteristics and clinical applications of the commonly available therapeutic radionuclides, as well as the problems and issues involved in translating novel radionuclides into clinical therapies.

  20. EBS Radionuclide Transport Abstraction

    Energy Technology Data Exchange (ETDEWEB)

    J.D. Schreiber

    2005-08-25

    The purpose of this report is to develop and analyze the engineered barrier system (EBS) radionuclide transport abstraction model, consistent with Level I and Level II model validation, as identified in ''Technical Work Plan for: Near-Field Environment and Transport: Engineered Barrier System: Radionuclide Transport Abstraction Model Report Integration'' (BSC 2005 [DIRS 173617]). The EBS radionuclide transport abstraction (or EBS RT Abstraction) is the conceptual model used in the total system performance assessment for the license application (TSPA-LA) to determine the rate of radionuclide releases from the EBS to the unsaturated zone (UZ). The EBS RT Abstraction conceptual model consists of two main components: a flow model and a transport model. Both models are developed mathematically from first principles in order to show explicitly what assumptions, simplifications, and approximations are incorporated into the models used in the TSPA-LA. The flow model defines the pathways for water flow in the EBS and specifies how the flow rate is computed in each pathway. Input to this model includes the seepage flux into a drift. The seepage flux is potentially split by the drip shield, with some (or all) of the flux being diverted by the drip shield and some passing through breaches in the drip shield that might result from corrosion or seismic damage. The flux through drip shield breaches is potentially split by the waste package, with some (or all) of the flux being diverted by the waste package and some passing through waste package breaches that might result from corrosion or seismic damage. Neither the drip shield nor the waste package survives an igneous intrusion, so the flux splitting submodel is not used in the igneous scenario class. The flow model is validated in an independent model validation technical review. The drip shield and waste package flux splitting algorithms are developed and validated using experimental data. The transport

  1. Studies of adsorption characteristics of activated carbons down to 4.5 K for the development of cryosorption pumps for fusion systems

    Energy Technology Data Exchange (ETDEWEB)

    Kasthurirengan, S.; Behera, U.; Vivek, G. A. [Centre for Cryogenic Technology, Indian institute of Science, Bangalore 560012 (India); Krishnamoorthy, V.; Gangradey, R. [Cryopump Group, Institute for Plasma Research, Gandhinagar, Gujarat 382428 (India); Udgata, S. S.; Tripati, V. S. [I-Design Engineering Solutions Ltd., Ubale Nagar, Wagholi, Pune 412207 (India)

    2014-01-29

    Cryosorption pump is the only possible device to pump helium, hydrogen and its isotopes in fusion environment, such as high magnetic field and high plasma temperatures. Activated carbons are known to be the most suitable adsorbent in the development of cryosorption pumps. For this purpose, the data of adsorption characteristics of activated carbons in the temperature range 4.5 K to 77 K are needed, but are not available in the literature. For obtaining the above data, a commercial micro pore analyzer operating at 77 K has been integrated with a two stage GM cryocooler, which enables the cooling of the sample temperature down to 4.5 K. A heat switch mounted between the second stage cold head and the sample chamber helps to raise the sample chamber temperature to 77 K without affecting the performance of the cryocooler. The detailed description of this system is presented elsewhere. This paper presents the results of experimental studies of adsorption isotherms measured on different types of activated carbons in the form of granules, globules, flake knitted and non-woven types in the temperature range 4.5 K to 10 K using Helium gas as the adsorbate. The above results are analyzed to obtain the pore size distributions and surface areas of the activated carbons. The effect of adhesive used for bonding the activated carbons to the panels is also studied. These results will be useful to arrive at the right choice of activated carbon to be used for the development of cryosorption pumps.

  2. Studies of adsorption characteristics of activated carbons down to 4.5 K for the development of cryosorption pumps for fusion systems

    Science.gov (United States)

    Kasthurirengan, S.; Behera, U.; Vivek, G. A.; Krishnamoorthy, V.; Gangradey, R.; Udgata, S. S.; Tripati, V. S.

    2014-01-01

    Cryosorption pump is the only possible device to pump helium, hydrogen and its isotopes in fusion environment, such as high magnetic field and high plasma temperatures. Activated carbons are known to be the most suitable adsorbent in the development of cryosorption pumps. For this purpose, the data of adsorption characteristics of activated carbons in the temperature range 4.5 K to 77 K are needed, but are not available in the literature. For obtaining the above data, a commercial micro pore analyzer operating at 77 K has been integrated with a two stage GM cryocooler, which enables the cooling of the sample temperature down to 4.5 K. A heat switch mounted between the second stage cold head and the sample chamber helps to raise the sample chamber temperature to 77 K without affecting the performance of the cryocooler. The detailed description of this system is presented elsewhere. This paper presents the results of experimental studies of adsorption isotherms measured on different types of activated carbons in the form of granules, globules, flake knitted and non-woven types in the temperature range 4.5 K to 10 K using Helium gas as the adsorbate. The above results are analyzed to obtain the pore size distributions and surface areas of the activated carbons. The effect of adhesive used for bonding the activated carbons to the panels is also studied. These results will be useful to arrive at the right choice of activated carbon to be used for the development of cryosorption pumps.

  3. Water-soluble copper phthalocyanine for optimization of gas-sensor characteristics of tin dioxide upon adsorption of ammonia

    Science.gov (United States)

    Komolov, A. S.; Lazneva, E. F.; Gerasimova, N. B.; Zimina, M. V.; Si, P.; Panina, Yu. A.

    2015-12-01

    This paper presents the results of the investigation into the electrical conductivity of thin films based on tin dioxide (SnO2) nanoparticles, a film consisting of copper phthalocyanine-3,4',4″,4‴-tetrasulfonic acid tetrasodium salt (CuPc-4SO3Na) molecules, and a composite film based on a mixture of equal parts by volume of the two materials upon adsorption of ammonia. The adsorption experiments have been carried out in a vacuum at room temperature with an increase in the ammonia pressure to 3 × 103 Pa from the residual gas base pressure of 5 × 10-1 Pa. It has been found that, in the case of a single-component film based on SnO2 nanoparticles, an increase in the electrical conductivity reaches 100% and is not completely reversible at room temperature after evacuation of the gas. For the single-component CuPc-4SO3Na film and the composite CuPc-4SO3Na/SnO2 film, the electrical conductivities increase by a factor of 400 and 150, respectively. Upon evacuation of ammonia to the base pressure, the electrical conductivity decreases to the initial values for 1 s. The mechanism of the influence of adsorbed ammonia molecules on the electrical conductivity of the composite material under investigation has been discussed using the model of the formation of the composite sample, according to which the organic component is located in voids between the SnO2 nanoparticles.

  4. Adsorption characteristics of U(VI) on Fe(III)Cr(III) (oxy)hydroxides synthesized at different temperatures.

    Science.gov (United States)

    Ahn, Hyangsig; Jo, Ho Young; Lee, Young Jae; Kim, Geon-Young

    2016-07-01

    In this study, the adsorption behavior of U(VI) on (oxy)hydroxides synthesized at different temperatures (25 and 75 °C) was investigated. Four (oxy)hydroxides were synthesized by drying slurries of Fe(III) and Fe(III)Cr(III) (oxy)hydroxide in a vacuum desiccator (25 °C) or in an oven (75 °C). Batch adsorption tests were conducted using the (oxy)hydroxides thus synthesized and groundwater containing uranium ions. In general, the U(VI) removal fraction significantly increased with increasing pH from 3 to 5, remained constant with increasing pH from 5 to 9, and decreased at pH greater than 9, regardless of the type of (oxy)hydroxides and solid-to-liquid ratio. The effect of pH on the U(VI) removal fraction was more significant at a low solid-to-liquid ratio. The oven-dried Fe(III) (oxy)hydroxide exhibited a U(VI) removal fraction lower than that of the vacuum-dried one, whereas the oven-dried Fe(III)Cr(III) (oxy)hydroxide exhibited a U(VI) removal fraction higher than that exhibited by the vacuum-dried one. X-ray photoelectron spectroscopy (XPS) analysis results indicated that the difference in the U(VI) removal fraction is attributed to the dissolution and precipitation of the Fe(III) (oxy)hydroxide during oven drying and dehydration of the Fe(III)Cr(III) (oxy)hydroxide during oven drying.

  5. Adsorption Characteristics of Amphoteric Cellulose for Persistent Pollutants%两性纤维素对持久性污染物的吸附特征

    Institute of Scientific and Technical Information of China (English)

    施文健; 陈肖云; 张元璋; 秦琴

    2011-01-01

    The adsorption kinetic and thermodynamic characteristics of amphoteric cellulose for Pb2 +, cationic turquoise blue GB, acid red B and R salt were studied. The thermodynamic parameters(AH, AS, AG) for the four persistent pollutants are as follows: AH is 9.33 kJ/mol, 2.88 kJ/mol, 5.96 kJ/mol and 7.95 kJ/mol, respectively; △S is 76.8 J/mol-K, 63.4 J/mol-K, 71.2 J/mol-K and 76.1 J/mol-K, respectively. At298K, △G is -13.6kJ/ mol, -16.0 kJ/mol, - 15.3 kJ/mol and- 14.7 kJ/mol, respectively; adsorption activation energy is 23.8 kJ/ mol, 18.6 kJ/mol, 3.9 kJ/mol, 7.7 kJ/mol, respectively. The adsorption of amphoteric cellulose for contaminants follows the first-order kinetic equation and Langmuir adsorption equation, the increase of temperature is favorable to the adsorption. The adsorption process for metal ions, water-soluble aromatic cationic and aromatic anionic organic compounds is mainly achieved by the chemisorption.%研究两性纤维素对Pb2+、阳离子翠蓝GB、酸性红B和R盐四种持久性污染物吸附过程的动力学和热力学问题,对吸附机理进行探讨.实验结果表明,两性纤维素对上述四种化合物的吸附过程的热力学参数依次为:△H 9.33 kJ/mol、2.88 kJ/mol、5.96 kJ/mol、7.95 kJ/mol;△S 76.8 J/mol·K、63.4 J/mol·K、71.2 J/mol·K、76.1 J/mol·K;298K时,△G-13.6 kJ/mol、-16.0 kJ/mol、-15.3 kJ/mol、-14.7kJ/mol;吸附活化能Ea23.8 kJ/mol、18.6 kJ/mol、3.9kJ/mol、7.7kJ/mol;吸附过程可用一级吸附动力学方程来描述,升高温度有利于吸附的进行;吸附符合Langmuir等温式;两性纤维素对重金属、水溶性芳香族阳离子和阴离子有机化合物的吸附主要为化学吸附.

  6. National Low-Level Waste Management Program Radionuclide Report Series

    Energy Technology Data Exchange (ETDEWEB)

    J.P. Adams; M.L. Carboneau; W.E. Allred

    1999-02-01

    The National Low Level Waste Management Program at the Idaho National Engineering and Environmental Laboratory has published a report containing key information about selected radionuclides that are most likely to contribute significantly to the radiation exposures estimated from a performance assessment of a low-level radioactive waste (LLW) disposal facility. The information includes physical and chemical characteristics, production means, waste forms, behavior of the radionuclide in soils, plants, groundwater, and air, and biological effects in animals and humans. The radionuclides included in this study comprise all of the nuclides specifically listed in 10CFR61.55, Tables 1 and 2, 3 H, 14 C, 59 Ni, 60 Co, 63 Ni, 90 Sr, 94 Nb, 99 Tc, 129 I, 137 Cs, 241 Pu, and 242 Cm. Other key radionuclides addressed in the report include 237 Np, 238 U, 239 Pu, and 241 Am. This paper summarizes key information contained within this report.

  7. National Low-Level Waste Management Program Radionuclide Report Series

    Energy Technology Data Exchange (ETDEWEB)

    Adams, James Paul; Carboneau, Michael Leonard; Allred, William Edgar

    1999-03-01

    The National Low Level Waste Management Program at the Idaho National Engineering and Environmental Laboratory has published a report containing key information about selected radionuclides that are most likely to contribute significantly to the radiation exposures estimated from a performance assessment of a low-level radioactive waste (LLW) disposal facility. The information includes physical and chemical characteristics, production means, waste forms, behavior of the radionuclide in soils, plants, groundwater, and air, and biological effects in animals and humans. The radionuclides included in this study comprise all of the nuclides specifically listed in 10CFR61.55, Tables 1 and 2, 3 H, 14 C, 59 Ni, 60 Co, 63 Ni, 90 Sr, 94 Nb, 99 Tc, 129 I, 137 Cs, 241 Pu, and 242 Cm. Other key radionuclides addressed in the report include 237 Np, 238 U, 239 Pu, and 241 Am. This paper summarizes key information contained within this report.

  8. Models for transport and fate of carbon, nutrients and radionuclides in the aquatic ecosystem at Oeregrundsgrepen

    Energy Technology Data Exchange (ETDEWEB)

    Erichsen, Anders Christian; Moehlenberg, Flemming; Closter, Rikke Margrethe; Sandberg, Johannes (DHI, Hoersholm (Denmark))

    2010-06-15

    quasi-stationary equilibrium within the model area. The coupled ecosystem and radionuclide models were used to simulate present conditions, i.e. 2020 AD. Six radionuclides were modelled explicitly in addition to C-14. They represent a wide range of accumulation potentials and partition coefficients (K{sub d}, distribution of radionuclides between water, sediment and biota). The ecosystem and associated radionuclide model include a detailed sediment module where radionuclides can be bound by adsorption to the organic and inorganic fractions, be precipitated, be transported by resuspension and later deposited at larger depths. With the exception of radionuclides with very low particle affinity, such as Cl-35, the majority of radionuclides released in basins where they were introduced via groundwater flow remained in the sediments even after a simulation period of eight years. The spread of radionuclides with high partition coefficients for sediments from areas with groundwater flow takes place by sediment resuspension and subsequent transport and sedimentation. In the case of radionuclides with lower partition coefficients, release from the sediments to the water column followed by transport of dissolved radionuclides by currents plays a larger role. A significant result of the modelling was the quantification of the seasonal and spatial variation in radionuclide accumulation and in bioconcentration factors (BCFs) with spatial variation of BCFs often ranging 2 to 3 orders of magnitude. This variation was dominated by spatial differences in concentrations of radionuclides in water. In basins where radionuclides were introduced by groundwater flow, BCFs were typically 2-3 orders of magnitude lower than in deep basins without radionuclide release in the groundwater. In phytoplankton and grazers, bioconcentration factors (BCFs) scaled linearly to partition coefficients (Kd), underlining the fact that adsorption is an important process for radionuclide accumulation in the

  9. Radionuclides in nephrology

    Energy Technology Data Exchange (ETDEWEB)

    Lausanne, A.B.D.

    1987-01-01

    In 47 expert contributions, this volume provides a summary of the latest research on radionuclides in nephro-urology together with current and new clinical applications especially in renovascular hypertension, kidney transplantation, and metabolic and urological diseases. In addition, attention is given to aspects of basic renal physiology and function and possible applications of nuclear magnetic resonance and spectroscopy in nephro-urology. New testing procedures which promise to improve diagnosis, and new radiopharmaceuticals are described. The reports are divided into eight sections, the first of which features studies on the renin-angiotensin system, cisplatin, atrial natriuretic factor and determining plasma oxalate. Four papers describe a number of new radiopharmaceuticals which have the potential to replace hippuran. In the third section, radionuclide methods for the measurement of renal function parameters are discussed. The book then focuses on the potential role of captopril in the improved diagnosis of renovascular hypertension. Applications of nuclear magnetic resonance and spectroscopy are demonstrated in the diagnosis of acute pyelonephritis, kidney assessment after lithotripsy, kidney evaluation prior to transplantation, and in monitoring renal ischemia during hypotension.

  10. Radionuclide - Soil Organic Matter Interactions

    DEFF Research Database (Denmark)

    Carlsen, Lars

    1985-01-01

    Interactions between soil organic matter, i.e. humic and fulvic acids, and radionuclides of primary interest to shallow land burial of low activity solid waste have been reviewed and to some extent studied experimentally. The radionuclides considered in the present study comprise cesium, strontium...

  11. Characteristics of fly ashes from full-scale coal-fired power plants and their relationship to mercury adsorption

    Science.gov (United States)

    Lu, Y.; Rostam-Abadi, M.; Chang, R.; Richardson, C.; Paradis, J.

    2007-01-01

    Nine fly ash samples were collected from the particulate collection devices (baghouse or electrostatic precipitator) of four full-scale pulverized coal (PC) utility boilers burning eastern bituminous coals (EB-PC ashes) and three cyclone utility boilers burning either Powder River Basin (PRB) coals or PRB blends,(PRB-CYC ashes). As-received fly ash samples were mechanically sieved to obtain six size fractions. Unburned carbon (UBC) content, mercury content, and Brunauer-Emmett-Teller (BET)-N2 surface areas of as-received fly ashes and their size fractions were measured. In addition, UBC particles were examined by scanning electron microscopy, high-resolution transmission microscopy, and thermogravimetry to obtain information on their surface morphology, structure, and oxidation reactivity. It was found that the UBC particles contained amorphous carbon, ribbon-shaped graphitic carbon, and highly ordered graphite structures. The mercury contents of the UBCs (Hg/UBC, in ppm) in raw ash samples were comparable to those of the UBC-enriched samples, indicating that mercury was mainly adsorbed on the UBC in fly ash. The UBC content decreased with a decreasing particle size range for all nine ashes. There was no correlation between the mercury and UBC contents of different size fractions of as-received ashes. The mercury content of the UBCs in each size fraction, however, generally increased with a decreasing particle size for the nine ashes. The mercury contents and surface areas of the UBCs in the PRB-CYC ashes were about 8 and 3 times higher than UBCs in the EB-PC ashes, respectively. It appeared that both the particle size and surface area of UBC could contribute to mercury capture. The particle size of the UBC in PRB-CYC ash and thus the external mass transfer was found to be the major factor impacting the mercury adsorption. Both the particle size and surface reactivity of the UBC in EB-PC ash, which generally had a lower carbon oxidation reactivity than the PRB

  12. Radioactivity, radionuclides, radiation

    CERN Document Server

    Magill, Joseph

    2005-01-01

    RADIOACTIVITY – RADIONUCLIDES – RADIATION is suitable for a general audience interested in topical environmental and human health radiological issues such as radiation exposure in aircraft, food sterilisation, nuclear medicine, radon gas, radiation dispersion devices ("dirty bombs")… It leads the interested reader through the three Rs of nuclear science, to the forefront of research and developments in the field. The book is also suitable for students and professionals in the related disciplines of nuclear and radiochemistry, health physics, environmental sciences, nuclear and astrophysics. Recent developments in the areas of exotic decay modes (bound beta decay of ‘bare’ or fully ionized nuclei), laser transmutation, nuclear forensics, radiation hormesis and the LNT hypothesis are covered. Atomic mass data for over 3000 nuclides from the most recent (2003) evaluation are included.

  13. Moisture adsorption characteristics of ginger slices Características de adsorção de umidade de gengibre em fatias

    Directory of Open Access Journals (Sweden)

    Joseph Alakali

    2009-03-01

    Full Text Available The moisture adsorption characteristics of dried ginger slices was studied to determine the effect of storage conditions on moisture adsorption for the purpose of shelf life prediction, selection of appropriate packaging materials, evaluate the goodness-of-fit of sorption models, and determine the thermodynamics of moisture adsorption for application in drying. There was a highly significant effect (p As características da adsorção de umidade de amostras de gengibre secas foram estudadas para se determinar o efeito das condições de armazenamento com o propósito de se prever a vida de prateleira ou validade, a seleção de materiais apropriados para empacotamento, avaliar a bondade de ajuste dos modelos de sorção e determinar a termodinâmica da adsorção de umidade para aplicação em secagem. Houve um efeito significativo (p < 0,05 da atividade de água, da temperatura e do pré-tratamento sobre o teor de umidade de equilíbrio higroscópico das amostras de gengibre secas. Sob atividade de água constante (a w, o teor de umidade de equilíbrio higroscópico (CEM diminuiu com o aumento da temperatura. O teor de umidade de equilíbrio higroscópico de todas as amostras aumentou com o aumento da atividade de água, sob temperatura constante. A umidade de sorção das amostras de gengibre com casca foi maior do que a das amostras de gengibre sem casca enquanto que a das amostras de gengibre não escaldo com e sem casca foi maior do que a das amostras de gengibre escaldado com e sem casca. A equação de Henderson permite previsões mais exatas das isotermas com o menor valor de média quadrática percentual (%RMS e, portanto, descreve melhor os dados de adsorção dos modelos de Guggenheim Anderson De-Boer (GAB, Oswin e Halsey, nesta ordem. A umidade de monocamada, em geral, diminuiu com a temperatura em todas as amostras. O calor isostérico diminuiu quando o teor de umidade se aproximou do valor assimptótico ou o calor latente de

  14. Solubility limits on radionuclide dissolution

    Energy Technology Data Exchange (ETDEWEB)

    Kerrisk, J.F.

    1984-12-31

    This paper examines the effects of solubility in limiting dissolution rates of a number of important radionuclides from spent fuel and high-level waste. Two simple dissolution models were used for calculations that would be characteristics of a Yucca Mountain repository. A saturation-limited dissolution model, in which the water flowing through the repository is assumed to be saturated with each waste element, is very conservative in that it overestimates dissolution rates. A diffusion-limited dissolution model, in which element-dissolution rates are limited by diffusion of waste elements into water flowing past the waste, is more realistic, but it is subject to some uncertainty at this time. Dissolution rates of some elements (Pu, Am, Sn, Th, Zr, Sm) are always limited by solubility. Dissolution rates of other elements (Cs, Tc, Np, Sr, C, I) are never solubility limited; their release would be limited by dissolution of the bulk waste form. Still other elements (U, Cm, Ni, Ra) show solubility-limited dissolution under some conditions. 9 references, 3 tables.

  15. Geochemical factors affecting radionuclide transport through near and far fields at a Low-Level Waste Disposal Site

    Energy Technology Data Exchange (ETDEWEB)

    Kaplan, D.I.; Seme, R.J. [Pacific Northwest Lab., Richland, WA (United States); Piepkho, M.G. [Westinghouse Hanford Co., Richland, WA (United States)

    1995-03-01

    The concentration of low-level waste (LLW) contaminants in groundwater is determined by the amount of contaminant present in the solid waste, rate of release from the waste and surrounding barriers, and a number of geochemical processes including adsorption, desorption, diffusion, precipitation, and dissolution. To accurately predict radionuclide transport through the subsurface, it is essential that the important geochemical processes affecting radionuclide transport be identified and, perhaps more importantly, accurately quantified and described in a mathematically defensible manner.

  16. Radioanalysis of RE enrichment of ion adsorption type RE ores

    CERN Document Server

    Zhao Shu Quan; Hu He Ping; Li Fu Sheng; Chen Ying Min; LiuShiMing

    2002-01-01

    Objective: To analyze the radioactivity in Rare Earth (RE) enrichment of ion adsorption type RE ores. Methods: Using HPGe-gamma spectrometer to analyze the activity ratio of gamma radionuclides in kind of samples, using FJ-2603 low background alpha, beta measurement apparatus to measure their total alpha and total beta activities, and using X-ray fluorescence spectrometer to analyze contents of La sub 2 O sub 3 and Y sub 2 O sub 3 , respectively. Results: HPGe gamma spectroscopy and X-ray fluorescence spectroscopy are simple, convenient and non-destructive methods of analyzing radionuclides and La sub 2 O sub 3 , Y sub 2 O sub 3 in RE enrichment of ion adsorption type RE ores, respectively. Conclusion: The basic data were provided for radiation protection and treatment of gas, liquid and solid waste in RE production of ion adsorption type RE ores; method and experience were provided for studying ion adsorption type RE ores

  17. 生物质热解焦对模拟烟气中汞吸附特性的实验研究%Experimental Study of Mercury Adsorption Characteristics of Biomass-pyrolysis Chars in the Simulated Flue Gas

    Institute of Scientific and Technical Information of China (English)

    树童; 王秦超; 卢平

    2012-01-01

    Different kinds of biomass-pyrolysis chars were prepared from four kinds of biomass named mulberry twig (MT) , nut shell (NS) , wheat straw (WS) , and rice husk (RH) in a fixed-bed pyrolysis reactor. The specific surface areas and pore structure parameters were measured by a surface area analyzer. The mercury adsorption characteristics of the biomass-pyrolysis chars were carried out in a fixed-bed adsorption reactor. The effects of biomass type, pyrolysis temperature, adsorption temperature and initial mercury concentration on mercury adsorption characteristics were investigated. The results indicated that: ( 1 ) At the same conditions of pyrolysis and adsorption reaction, the adsorption char- acteristics of NS char were the best, MT char and WS chars were in middle, and RS char was the worst. (2) At the py- rolysis temperatures of 400℃- 600℃, biomass chars pyrolyzed at 600℃ showed the best adsorption characteristics, and biomass chars pyrolyzed at 400℃ performed the worst adsorption characteristics. ( 3 ) The unit mercury adsorption capacity of biomass-pyrolysis chars decreased with increasing the adsorption temperature significantly at the adsorption temperature of 60℃-120℃. (4) The unit adsorption capacity of biomass-pyrolysis chars decreased slightly with increasing initial mercury concentration at the initial mercury concentration of 13.5 μg/m3 - 38.1 μg/m3.%以桑树枝、核桃壳、麦秆和稻秆4种生物质为原料,利用固定床热解实验台制备不同的生物质热解焦,采用比表面积与孔隙度分析仪测量了生物质热解焦的比表面积及其孔隙结构参数.利用固定床吸附实验装置,研究了生物质种类、热解温度、吸附温度及汞初始浓度等因素对模拟烟气中汞吸附性能的影响.结果表明:(1)在相同的热解和吸附条件下,核桃壳热解焦的吸附效果最好,其次是桑树枝热解焦和麦秆热解焦,稻秆热

  18. An investigation of the adsorption characteristics of 5 prime ATP and 5 prime AMP onto the surface of CaSO sub 4 x 2H sub 2 O

    Science.gov (United States)

    Calderon, J.; Sweeney, M. A.

    1986-01-01

    A model has been proposed (Lahev and Chans, 1982) in which solid surfaces can act as a site for catalytic activity of condensation reactions for certain biomolecules. From this model, the adsorption characteristics of 5'ATP and 5'AMP onto the surface of CaSO4 2H2O was chosen for study. It has been proven that 5'ATP and 5'AMP do adsorb onto the surface of CaSO4. Studies were then made to determine the dependence of adsorption versus time, concentration, ionic strength and pH. It was found that the adsorption of the nucleotides is highly pH dependent, primarily determined by the phosphate acid groups of the nucleic acid molecule. From this investigation, the data obtained are discussed in relation to the model for the prebiotic earth.

  19. Anthropogenic radionuclides in the environment

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Q; Weng, J; Wang, J

    2007-11-15

    Studies of radionuclides in the environment have entered a new era with the renaissance of nuclear energy and associated fuel reprocessing, geological disposal of high-level nuclear wastes, and concerns about national security with respect to nuclear non-proliferation. This work presents an overview of anthropogenic radionuclide contamination in the environment, as well as the salient geochemical behavior of important radionuclides. We first discuss the following major anthropogenic sources and current development that contribute to the radionuclide contamination of the environment: (1) nuclear weapons program; (2) nuclear weapons testing; (3) nuclear power plants; (4) commercial fuel reprocessing; (5) geological repository of high-level nuclear wastes, and (6) nuclear accidents. Then, we summarize the geochemical behavior for radionuclides {sup 99}Tc, {sup 129}I, and {sup 237}Np, because of their complex geochemical behavior, long half-lives, and presumably high mobility in the environment. Biogeochemical cycling and environment risk assessment must take into account speciation of these redox-sensitive radionuclides.

  20. Analysis of shale adsorption characteristics and adsorption abnormal cause under high pressure%高压下页岩吸附特性及吸附异常原因分析

    Institute of Scientific and Technical Information of China (English)

    刘小磊; 吴财芳; 夏大平

    2014-01-01

    从分子学角度出发,探讨了页岩吸附量随压力变化趋势可能的内在原因。并结合模拟实验数据,分析了页岩在吸附后期出现吸附异常现象的原因。研究认为,甲烷分子在页岩表面的吸附与分子间引斥力的相互作用密切相关。在吸附初期,页岩表面能相对较大,甲烷分子和页岩表面分子间作用力以吸引力为主且逐渐增大,页岩吸附量随压力升高而增大且增加较快;在吸附中期,页岩表面能减小,甲烷分子和页岩表面分子间作用力由吸引力向排斥力转变,页岩吸附量随压力升高增加变缓达到最大值,此时吸附速率与解吸速率动态平衡;在吸附后期的超高压下,页岩表面能趋于零,甲烷分子和页岩表面分子间作用力以排斥力为主且增加较快,页岩吸附量随压力的升高而降低,甚至出现负值。页岩吸附异常的原因主要有两点:一是页岩具有相对低的吸附量,而且甲烷分子直径大于氦气,致使实验所用自由体积值偏大,造成计算结果“负吸附”;二是高压下页岩中甲烷处于超临界吸附且具有较大的分子间斥力。%In view of molecular ,the possible internal cause of shale adsorption trend with pressure change was discussed .And according to simulation data ,the causes of shale adsorption abnormal in the late adsorption were analyzed .Results show that methane molecules adsorbed on the surface of the shale is closed related to the interaction of gravitation and repulsion between molecules .Early in the adsorption ,shale surface energy is relatively large ,the intermolecular force between methane molecules and shale surface molecules is gradually increasing gravitation ,which leads shale adsorption to increasing rapidly with pressure increasing .In the middle of adsorption ,shale surface energy decreases ,the intermolecular force between methane molecules and shale surface molecules transforms

  1. Characterization of radionuclide-chelating agent complexes found in low-level radioactive decontamination waste. Literature review

    Energy Technology Data Exchange (ETDEWEB)

    Serne, R.J.; Felmy, A.R.; Cantrell, K.J.; Krupka, K.M.; Campbell, J.A.; Bolton, H. Jr.; Fredrickson, J.K. [Pacific Northwest National Lab., Richland, WA (United States)

    1996-03-01

    The US Nuclear Regulatory Commission is responsible for regulating the safe land disposal of low-level radioactive wastes that may contain organic chelating agents. Such agents include ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentaacetic acid (DTPA), picolinic acid, oxalic acid, and citric acid, and can form radionuclide-chelate complexes that may enhance the migration of radionuclides from disposal sites. Data from the available literature indicate that chelates can leach from solidified decontamination wastes in moderate concentration (1--100 ppm) and can potentially complex certain radionuclides in the leachates. In general it appears that both EDTA and DTPA have the potential to mobilize radionuclides from waste disposal sites because such chelates can leach in moderate concentration, form strong radionuclide-chelate complexes, and can be recalcitrant to biodegradation. It also appears that oxalic acid and citric acid will not greatly enhance the mobility of radionuclides from waste disposal sites because these chelates do not appear to leach in high concentration, tend to form relatively weak radionuclide-chelate complexes, and can be readily biodegraded. In the case of picolinic acid, insufficient data are available on adsorption, complexation of key radionuclides (such as the actinides), and biodegradation to make definitive predictions, although the available data indicate that picolinic acid can chelate certain radionuclides in the leachates.

  2. Model for radionuclide transport in running waters

    Energy Technology Data Exchange (ETDEWEB)

    Jonsson, Karin; Elert, Mark [Kemakta Konsult AB, Stockholm (Sweden)

    2005-11-15

    , however, the approximation of equilibrium chemistry is assumed to be sufficient for order of magnitude predictions when a constant inflow of radionuclides is considered. A first sensitivity analysis of the model is performed in which different model parameters have been varied. At the time for the model development, almost no detailed site-specific information about e.g. channel geometry or sediment characteristics were available. Simulations were therefore performed for a hypothetical case, where the ranges of possible parameter values was based on literature information, generalizations from other stream systems and some site-specific information such as large-scale information of the morphology at the present sites. For order of magnitude predictions of the concentration or amount of radionuclides in the different parts of the stream ecosystem, a yearly mean value of the water flow was assumed to be sufficient. Therefore, the further sensitivity analyses were performed for constant flow conditions. The sensitivity analyses indicated that the main retention along the stream is due to uptake within the sediment. Initially, the uptake will cause a retardation of the solute transport. The sediment capacity is however limited and after saturation, the outflow of radionuclides in the longitudinal direction will be completely determined by the inflow to the system. The time for reaching this equilibrium and the equilibrium concentration in the sediment varies however with different conditions and radionuclides, e.g. due to sorption characteristics, sedimentation velocity and advective velocity within the sediment. The degree of variation caused by different factors is, however, different. In the simulations performed in this study, the time for reaching equilibrium ranges from less than a year to a couple of hundred years. For predictions of the dose to humans, the accumulated amount in the sediment should also be considered and not only the concentration in the stream water

  3. Radionuclide salivary gland imaging

    Energy Technology Data Exchange (ETDEWEB)

    Mishkin, F.S.

    1981-10-01

    Salivary gland imaging with 99mTc as pertechnetate provides functional information concerning trapping and excretion of the parotid and submandibular glands. Anatomic information gained often adds little to clinical evaluation. On the other hand, functional information may detect subclinical involvement, which correlates well with biopsy of the minor labial salivary glands. Salivary gland abnormalities in systemic disease such as sarcoidosis, rheumatoid arthritis, lupus erythematosus, and other collagenvascular disorders may be detected before they result in the clinical manifestaions of Sjoegren's syndrome. Such glands, after initially demonstrating increased trapping in the acute phase, tend to have decreased trapping and failure to discharge pertechnetate in response to an appropriate physiologic stimulus. Increased uptake of gallium-67 citrate often accompanies these findings. Inflammatory parotitis can be suspected when increased perfusion is evident on radionuclide angiography with any agent. The ability of the salivary gland image to detect and categorize mass lesions, which result in focal areas of diminished activity such as tumors, cysts, and most other masses, is disappointing, while its ability to detect and categorize Warthin's tumor, which concentrates pertechnetate, is much more valuable, although not specific.

  4. Adsorption of gaseous hydrocarbons on activated carbon: characteristic kinetic curve. [Includes effect of surface migration on kinetics

    Energy Technology Data Exchange (ETDEWEB)

    Costa, E.; Calleja, G.; Domingo, F.

    1985-06-01

    The internal diffusion coefficients, D /sub i/ , of pure methane, ethane and ethylene as well as some of their binary and ternary mixtures, have been calculated at 20/sup 0/C for solid particles of a commercial activated carbon. It has been observed that the contribution of the surface migration mechanism to the global mass transfer process inside the adsorbent particles can be as much as 70-80%. Values for the surface migration coefficient D /sub s/ have also been calculated from the relation D /sub i/ = D /sub g/ + KD /sub s/ , where K is a dimensionless mean slope factor. Values found for both coefficients are of the same order of magnitude as those reported in the literature for similar systems. All the values for the internal diffusion coefficients of these pure components and their mixtures fit into a single correlation curve, the characteristic kinetic curve of the adsorbent.

  5. Pore Structure Characteristics of Activated Carbon Fibers Derived from Poplar Bark Liquefaction and Their Use for Adsorption of Cu(II

    Directory of Open Access Journals (Sweden)

    Jiahui Zhang

    2014-11-01

    Full Text Available In this work, wood bark was liquefied to prepare activated carbon fibers, which were obtained through melt-spinning, stabilization, carbonizing, and stream activation. The effects of varying activation temperature on the pore structure and the adsorption capacity of the liquefied wood bark activated carbon fibers (LWBACFs were studied using analysis of nitrogen adsorption-desorption isotherms and static adsorption of copper (II ions from aqueous solution. The results indicated that higher specific surface area was obtained as the activation temperature increased. The specific surface area reached a maximum of 1962 m2/g with an average pore diameter of approximately 2 nm. Carbonization at 200 °C played an important role in the formation of pore structure. The adsorption of copper by LWBACFs was high, with a peak of 15 mg/g. All parameters showed that LWBACFs performed well in the adsorption of micropores.

  6. Waste Isolation Safety Assessment Program. Task 4. Third Contractor Information Meeting. [Adsorption-desorption on geological media

    Energy Technology Data Exchange (ETDEWEB)

    1980-06-01

    The study subject of this meeting was the adsorption and desorption of radionuclides on geologic media under repository conditions. This volume contans eight papers. Separate abstracts were prepared for all eight papers. (DLC)

  7. National Low-Level Waste Management Program Radionuclide Report Series

    Energy Technology Data Exchange (ETDEWEB)

    Rudin, M.J.; Garcia, R.S.

    1992-02-01

    This report, Volume 3 of the National Low-Level Radioactive Waste Management Program Radionuclide Report Series, discusses the radiological and chemical characteristics of carbon-14. The report also discusses waste streams that contain carbon-14, waste forms that contain carbon-14, and carbon-14 behavior in the environment and in the human body.

  8. National Low-Level Waste Management Program Radionuclide Report Series

    Energy Technology Data Exchange (ETDEWEB)

    Rudin, M.J.; Stanton, C.; Patterson, R.G.; Garcia, R.S.

    1992-02-01

    This report, Volume 2 of the National Low-Level Radioactive Waste Management Program Radionuclide Report Series, discusses radiological and chemical characteristics of technetium-99. This report also includes discussions about waste streams in which technetium-99 can be found, waste forms that contain technetium-99, and technetium-99's behavior in the environment and in the human body.

  9. National Low-Level Waste Management Program Radionuclide Report Series

    Energy Technology Data Exchange (ETDEWEB)

    Rudin, M.J.; Garcia, R.S.

    1992-02-01

    This report, Volume 4 of the National Low-Level Radioactive Waste Management Program Radionuclide Report Series, discusses radiological and chemical characteristics about iodine-129. This report also includes discussions about waste streams that contain iodine-129, waste forms that contain iodine-129, and iodine-129's behavior in the environment, as well as in the human body.

  10. Radionuclides in groundwater flow system understanding

    Science.gov (United States)

    Erőss, Anita; Csondor, Katalin; Horváth, Ákos; Mádl-Szőnyi, Judit; Surbeck, Heinz

    2017-04-01

    Using radionuclides is a novel approach to characterize fluids of groundwater flow systems and understand their mixing. Particularly, in regional discharge areas, where different order flow systems convey waters with different temperature, composition and redox-state to the discharge zone. Radium and uranium are redox-sensitive parameters, which causes fractionation along groundwater flow paths. Discharging waters of regional flow systems are characterized by elevated total dissolved solid content (TDS), temperature and by reducing conditions, and therefore with negligible uranium content, whereas local flow systems have lower TDS and temperature and represent oxidizing environments, and therefore their radium content is low. Due to the short transit time, radon may appear in local systems' discharge, where its source is the soil zone. However, our studies revealed the importance of FeOOH precipitates as local radon sources throughout the adsorption of radium transported by the thermal waters of regional flow systems. These precipitates can form either by direct oxidizing of thermal waters at discharge, or by mixing of waters with different redox state. Therefore elevated radon content often occurs in regional discharge areas as well. This study compares the results of geochemical studies in three thermal karst areas in Hungary, focusing on radionuclides as natural tracers. In the Buda Thermal Karst, the waters of the distinct discharge areas are characterized by different temperature and chemical composition. In the central discharge area both lukewarm (20-35°C, 770-980 mg/l TDS) and thermal waters (40-65°C, 800-1350 mg/l TDS), in the South only thermal water discharge (33-43°C, 1450-1700 mg/l TDS) occur. Radionuclides helped to identify mixing of fluids and to infer the temperature and chemical composition of the end members for the central discharge area. For the southern discharge zone mixing components could not be identified, which suggests different cave

  11. The Surface Adsorption Characteristics of Kapok Fiber%木棉纤维表面吸附特性

    Institute of Scientific and Technical Information of China (English)

    孙向玲; 徐广标; 王府梅

    2011-01-01

    利用OCA15EC光学接触角测量仪测试了不同特性液体(如色拉油、废油、机油)在木棉纤维上的静态接触角和动态接触角,研究表明:木棉纤维是一种优良的疏水亲油性纤维,对水的静态接触角为135.89°,对各种油液的静态接触角均小于60°,水在木棉纤维表面能够形成完整的液滴接触角并不随时间变化,而不同油液在木棉纤维表面瞬间铺展,尽管因油液不同铺展速度略有差异,但总体规律类似.木棉纤维对各种液体的吸附特性主要取决于纤维表面蜡质和木棉纤维的大中腔结构,同时也与测试液体特性密切相关.%The static and dynamic contact angle of kapok fibers with different kinds of liquids such as vegetable oil, used oil and engine oil is investigated using OCA15EC contact angle measuring device. It is found that, kapok fiber is an excellent oleophylic and hydrophobic fiber with the contact angle of kapok fiber to water is 139. 55°, but it is less than 60°to various kinds of oil. The contact angle of kapok to water is the constant with the time flies. All the oil liquids on the kapok fibers have the quick spread rates, and the spread curves are similar though the spread rates varied with the viscosity and surface tension of the liquids. The static and dynamic contact angles are determined by the fiber morphological structure, chemical composition, surface free energy of kapok fiber, also related with the characteristics of different liquids.

  12. Characteristics of equilibrium, kinetics studies for adsorption of Hg(II), Cu(II), and Ni(II) ions by thiourea-modified magnetic chitosan microspheres.

    Science.gov (United States)

    Zhou, Limin; Wang, Yiping; Liu, Zhirong; Huang, Qunwu

    2009-01-30

    Magnetic chitosan microspheres were prepared and chemically modified with thiourea (TMCS) for adsorption of metal ions. TMCS obtained were investigated by means of X-ray diffraction (XRD), IR, magnetic properties and thermogravimetric analysis (TGA). The adsorption properties of TMCS toward Hg(2+), Cu(2+), and Ni(2+) ions were evaluated. Various factors affecting the uptake behavior such as contact time, temperature, pH and initial concentration of the metal ions were investigated. The kinetics was evaluated utilizing the pseudo-first-order, pseudo-second-order, and the intra-particle diffusion models. The equilibrium data were analyzed using the Langmuir, Freundlich, and Tempkin isotherm models. The adsorption kinetics followed the mechanism of the pseudo-second-order equation for all systems studied, evidencing chemical sorption as the rate-limiting step of adsorption mechanism and not involving a mass transfer in solution. The best interpretation for the equilibrium data was given by Langmuir isotherm, and the maximum adsorption capacities were 625.2, 66.7, and 15.3mg/g for Hg(2+), Cu(2+), and Ni(2+) ions, respectively. TMCS displayed higher adsorption capacity for Hg(2+) in all pH ranges studied. The adsorption capacity of the metal ions decreased with increasing temperature. The metal ion-loaded TMCS with were regenerated with an efficiency of greater than 88% using 0.01-0.1M ethylendiamine tetraacetic acid (EDTA).

  13. Effect of copper stress on growth characteristics and fermentation properties of Saccharomyces cerevisiae and the pathway of copper adsorption during wine fermentation.

    Science.gov (United States)

    Sun, Xiangyu; Liu, Lingling; Zhao, Yu; Ma, Tingting; Zhao, Fang; Huang, Weidong; Zhan, Jicheng

    2016-02-01

    The effect of copper stress on the fermentation performance of Saccharomyces cerevisiae and its copper adsorption pathway during alcoholic fermentation were investigated in this study. At the limits imposed by the regulations of the European Union and South African (⩽ 20 mg/l), copper had no effect on the cell growth of S. cerevisiae, but its fermentation performance was inhibited to a certain extent. Therefore, the regulated limit should be further reduced (⩽ 12.8 mg/l). Under 9.6-19.2 mg/l copper stress, S. cerevisiae could absorb copper; the copper removal ratio and the unit strain adsorption were 60-81% and 2.72-9.65 mg/g, respectively. S. cerevisiae has a non-biological adsorption of copper, but compared with biological (living yeast) adsorption, the non-biological adsorption was very low. The copper adsorption way of S. cerevisiae was primarily via biological (living yeast) adsorption, which was a two-step process.

  14. 改性玉米芯吸附溶液中 U()Ⅵ的热力学特征%Adsorption thermodynamic characteristics of U(Ⅵ) on modified corncob in aqueous solution

    Institute of Scientific and Technical Information of China (English)

    李小燕; 刘义保; 花明; 李金轩; 高柏

    2013-01-01

    The corncob modified by KMnO4 in microwave was used for the adsorption of U(Ⅵ) ions from aqueous solution, and the thermodynamic characteristics on the adsorption were discussed. The results show that the adsorption capacity of the modified corncob increases with increasing temperature. Langmuir and Freundlich isotherms were used to fit the adsorption equilibrium data, and it is found that the adsorption process follows preferably the Langmuir isotherm adsorption model, which indicates that the adsorption mainly occurs in active region on the surface of modified corncob and belongs to the monolayer adsorption. The thermodynamic parameters, such as Gibbs free energy ΔG, enthalpy ΔH and entropy ΔS changes for the adsorption of U(Ⅵ) were calculated and discussed. When the concentration of U(Ⅵ) is below 80 mg/L, the Gibbs free energies of adsorption at all temperatures are negative and decrease with increasing temperature, which indicates that the adsorption process is spontaneous and the higher the temperature is, the greater the degree of spontaneous is. The entropy change ΔS and enthalpy change ΔH are positive, so the adsorption process is a heat absorption, the higher the temperature is, the more beneficial to adsorption is.%  以微波辅助 KMnO4改性玉米芯为吸附剂来吸附溶液中的 U(Ⅵ),探讨改性玉米芯吸附溶液中 U(Ⅵ)的热力学特征。结果表明:随着温度的升高,改性玉米芯对 U(Ⅵ)的吸附量增大。Langmuir 模型能更好地反映吸附过程特征,说明吸附主要发生在改性玉米芯表面的活性区域,属于单分子层吸附。吸附热力学参数ΔG、ΔH 和ΔS的计算结果表明,所有温度下ΔG 在 U(Ⅵ)初始浓度≤80 mg/L 时均为负值,且温度越高ΔG 值越负,表明改性玉米芯对 U(Ⅵ)的吸附过程是一个自发的过程,且温度越高,自发程度越大。焓变ΔH 和熵变ΔS 都为正值,说明吸附过程吸热,温度越高,越有利于吸附的进行。

  15. Radionuclide Retention in Concrete Wasteforms

    Energy Technology Data Exchange (ETDEWEB)

    Wellman, Dawn M.; Jansik, Danielle P.; Golovich, Elizabeth C.; Cordova, Elsa A.

    2012-09-24

    Assessing long-term performance of Category 3 waste cement grouts for radionuclide encasement requires knowledge of the radionuclide-cement interactions and mechanisms of retention (i.e., sorption or precipitation); the mechanism of contaminant release; the significance of contaminant release pathways; how wasteform performance is affected by the full range of environmental conditions within the disposal facility; the process of wasteform aging under conditions that are representative of processes occurring in response to changing environmental conditions within the disposal facility; the effect of wasteform aging on chemical, physical, and radiological properties; and the associated impact on contaminant release. This knowledge will enable accurate prediction of radionuclide fate when the wasteforms come in contact with groundwater. Data collected throughout the course of this work will be used to quantify the efficacy of concrete wasteforms, similar to those used in the disposal of LLW and MLLW, for the immobilization of key radionuclides (i.e., uranium, technetium, and iodine). Data collected will also be used to quantify the physical and chemical properties of the concrete affecting radionuclide retention.

  16. Effect of the ionic strength of a mobile phase on the chromatographic retention and thermodynamic characteristics of the adsorption of enantiomers of α-phenylcarboxylic acids on a chiral adsorbent with grafted antibiotic eremomycin

    Science.gov (United States)

    Reshetova, E. N.

    2017-01-01

    The effect the ionic strength of an aqueous ethanol mobile phase containing buffer salt has the on retention and thermodynamics of adsorption of optical isomers of some α-phenylcarboxylic acids on chiral adsorbent Nautilus-E with grafted antibiotic eremomycin is investigated. It is shown that ion exchange processes participate in the adsorption of enantiomers of α-phenylcarboxylic acids. It is established that electrostatic interactions contribute to the retention of enantiomers of α-phenylcarboxylic acids and affect selectivity only slightly. The dependences of retention characteristics, selectivity, and thermodynamic parameters on the concentration of the buffer salt in the eluent are determined. A statistical analysis of enthalpy-entropy compensation is performed, and the compensation effect is shown to be true. It is found that the points corresponding to the investigated adsorbates are distributed over the compensation dependence according to the spatial structural characteristics of molecules.

  17. Quantitative modeling of Cerenkov light production efficiency from medical radionuclides.

    Directory of Open Access Journals (Sweden)

    Bradley J Beattie

    Full Text Available There has been recent and growing interest in applying Cerenkov radiation (CR for biological applications. Knowledge of the production efficiency and other characteristics of the CR produced by various radionuclides would help in accessing the feasibility of proposed applications and guide the choice of radionuclides. To generate this information we developed models of CR production efficiency based on the Frank-Tamm equation and models of CR distribution based on Monte-Carlo simulations of photon and β particle transport. All models were validated against direct measurements using multiple radionuclides and then applied to a number of radionuclides commonly used in biomedical applications. We show that two radionuclides, Ac-225 and In-111, which have been reported to produce CR in water, do not in fact produce CR directly. We also propose a simple means of using this information to calibrate high sensitivity luminescence imaging systems and show evidence suggesting that this calibration may be more accurate than methods in routine current use.

  18. 100 years of radionuclide metrology.

    Science.gov (United States)

    Judge, S M; Arnold, D; Chauvenet, B; Collé, R; De Felice, P; García-Toraño, E; Wätjen, U

    2014-05-01

    The discipline of radionuclide metrology at national standards institutes started in 1913 with the certification by Curie, Rutherford and Meyer of the first primary standards of radium. In early years, radium was a valuable commodity and the aim of the standards was largely to facilitate trade. The focus later changed to providing standards for the new wide range of radionuclides, so that radioactivity could be used for healthcare and industrial applications while minimising the risk to patients, workers and the environment. National measurement institutes responded to the changing demands by developing new techniques for realising primary standards of radioactivity. Looking ahead, there are likely to be demands for standards for new radionuclides used in nuclear medicine, an expansion of the scope of the field into quantitative imaging to facilitate accurate patient dosimetry for nuclear medicine, and an increasing need for accurate standards for radioactive waste management and nuclear forensics.

  19. Adsorption characteristics of rebaudioside A and stevioside on cross-linked poly(styrene-co-divinylbenzene) macroporous resins functionalized with chloromethyl, amino and phenylboronic acid groups.

    Science.gov (United States)

    Ye, Fayin; Yang, Ruijin; Hua, Xiao; Zhao, Guohua

    2014-09-15

    The adsorptive separation of each steviol glycoside from aqueous solutions by polymeric adsorbents has attracted a lot of interest in recent years. The adsorption properties of chloromethylated cross-linked poly(styrene-co-divinylbenzene) macroporous resins, functionalised with chloromethyl, amino and phenylboronic acid groups, towards rebaudioside A and stevioside were studied. The results revealed that the resins with amino and phenylboronic acid groups preferred to adsorb stevioside rather than rebaudioside A, and their adsorption kinetics fitted a pseudo-second-order model. Isothermal equilibrium curves of rebaudioside A and stevioside showed a good fitness with the Langmuir and Freundlich models. The adsorption of rebaudioside A and stevioside onto resins was a spontaneous and exothermic process as indicated by the negative values in free energy and enthalpy. Results from the resin-packed column demonstrated that an effluent rich in rebaudioside A (purity 98%) was obtained prior to the breakthrough point of stevioside.

  20. Influence of pyrolysis temperature on characteristics and phosphate adsorption capability of biochar derived from waste-marine macroalgae (Undaria pinnatifida roots).

    Science.gov (United States)

    Jung, Kyung-Won; Kim, Kipal; Jeong, Tae-Un; Ahn, Kyu-Hong

    2016-01-01

    The collected roots of Undaria pinnatifida, the main waste in farming sites, accounting for 40-60% of annual production, was pyrolyzed under temperature ranging from 200 to 800°C to evaluate the influence of pyrolysis temperature on biochar properties and phosphate adsorption capacity. It was confirmed that an increase in the pyrolysis temperature led to a decrease of the yield of biochar, while ash content remained almost due to carbonization followed by mineralization. Elemental analysis results indicated an increase in aromaticity and decreased polarity at a high pyrolysis temperature. When the pyrolysis temperature was increased up to 400°C, the phosphate adsorption capacity was enhanced, while a further increase in the pyrolysis temperature lowered the adsorption capacity due to blocked pores in the biochar during pyrolysis. Finally, a pot experiment revealed that biochar derived from waste-marine macroalgae is a potent and eco-friendly alternative material for fertilizer after phosphate adsorption.

  1. National low-level waste management program radionuclide report series, Volume 15: Uranium-238

    Energy Technology Data Exchange (ETDEWEB)

    Adams, J.P.

    1995-09-01

    This report, Volume 15 of the National Low-Level Waste Management Program Radionuclide Report Series, discusses the radiological and chemical characteristics of uranium-238 ({sup 238}U). The purpose of the National Low-Level Waste Management Program Radionuclide Report Series is to provide information to state representatives and developers of low-level radioactive waste disposal facilities about the radiological, chemical, and physical characteristics of selected radionuclides and their behavior in the waste disposal facility environment. This report also includes discussions about waste types and forms in which {sup 238}U can be found, and {sup 238}U behavior in the environment and in the human body.

  2. Adsorption characteristics of UO{sub 2}{sup 2+} and Th{sup 4+} ions from simulated radioactive solutions onto chitosan/clinoptilolite sorbents

    Energy Technology Data Exchange (ETDEWEB)

    Humelnicu, Doina, E-mail: doinah@uaic.ro [' Al. I. Cuza' University of Iasi, Faculty of Chemistry, Bd. 11 Carol I, 700506 Iasi (Romania); Dinu, Maria Valentina, E-mail: vdinu@icmpp.ro [' Petru Poni' Institute of Macromolecular Chemistry, Aleea Grigore Ghica Voda 41A, 700487 Iasi (Romania); Dragan, Ecaterina Stela, E-mail: sdragan@icmpp.ro [' Petru Poni' Institute of Macromolecular Chemistry, Aleea Grigore Ghica Voda 41A, 700487 Iasi (Romania)

    2011-01-15

    Adsorption features of UO{sub 2}{sup 2+} and Th{sup 4+} ions from simulated radioactive solutions onto a novel chitosan/clinoptilolite (CS/CPL) composite as beads have been investigated compared with chitosan cross-linked with epichlorohydrin. The effects of contact time, the initial metal ion concentration, sorbent mass and temperature on the adsorption capacity of the CS-based sorbents were investigated. The adsorption kinetics was well described by the pseudo-second order equation, and the adsorption isotherms were better fitted by the Sips model. The maximum experimental adsorption capacities were 328.32 mg Th{sup 4+}/g composite, and 408.62 mg UO{sub 2}{sup 2+}/g composite. The overall adsorption tendency of CS/CPL composite toward UO{sub 2}{sup 2+} and Th{sup 4+} radiocations in the presence of Cu{sup 2+}, Fe{sup 2+} and Al{sup 3+}, under competitive conditions, followed the order: Cu{sup 2+} > UO{sub 2}{sup 2+} > Fe{sup 2+} > Al{sup 3+}, and Cu{sup 2+} > Th{sup 4+} > Fe{sup 2+} > Al{sup 3+}, respectively. The negative values of Gibbs free energy of adsorption indicated the spontaneity of the adsorption of radioactive ions on both the CS/CPL composite and the cross-linked CS. The desorption level of UO{sub 2}{sup 2+} from the composite CS/CPL, by using 0.1 M Na{sub 2}CO{sub 3}, was around 92%, and that of Th{sup 4+} ions, performed by 0.1 M HCl, was around 85%, both values being higher than the desorption level of radiocations from the cross-linked CS, which were 89% and 83%, respectively.

  3. Efficient and rapid adsorption characteristics of templating modified guar gum and silica nanocomposite toward removal of toxic reactive blue and Congo red dyes.

    Science.gov (United States)

    Pal, Sagar; Patra, Abhay Shankar; Ghorai, Soumitra; Sarkar, Amit Kumar; Mahato, Vivekananda; Sarkar, Supriyo; Singh, R P

    2015-09-01

    The present study highlights the potentiality of sol-gel synthesized guar gum-graft-poly (acrylamide)/silica (g-GG/SiO2) hybrid nanocomposite toward the rapid removal of toxic reactive blue 4 (RB) and Congo red (CR) dyes from aqueous solution. Various physicochemical characterizations support the feasibility of the functionalized guar gum matrix as efficient template for the formation of homogeneous nanoscale silica particles. The composite demonstrates rapid and superior adsorption efficiency of RB (Qmax: 579.01 mg g(-1) within 40 min) and CR (Qmax: 233.24 mg g(-1) within 30 min) dyes from aqueous environment. Here, the pH driven adsorption process depends strongly on the ionic strength of the salt solution. The adsorption kinetics data predicts that pseudo second-order (surface adsorption) and intraparticle diffusion take place simultaneously. The adsorption equilibrium is in good agreement with the Langmuir isotherm, while the thermodynamics study confirms spontaneous nature of the adsorption process. Desorption study predicts the excellent regenerative efficacy of nanocomposite.

  4. SrCl2-NH3化学吸附式制冷工质对吸附特性的研究%STUDY ON THE ADSORPTION CHARACTERISTICS OF SrCl2-NH3 CHEMISORPTION REFRIGERATION WORKING PAIR

    Institute of Scientific and Technical Information of China (English)

    陈砺; 谭盈科

    2001-01-01

    A study on the adsorption characteristics of the chemisorptionrefrigeration working pair using SrCl2 as adsorbent and NH3 as refrigerant was performed.The adsorption isotherms were obtained,the adsorpt i on isotherm equations were fit and the chemisorption mechanisms were discussed.T he results showed that SrCl2-NH3 is an excellent working pair in its larg e adsorption refrigeration capacity per unit weight of adsorbent and suitable fo r solar energy and low grade waste heat.%对以SrCl2为吸附剂、NH3为致冷剂所组成的化学吸附式制冷工质对的吸附性能进行了研究,得到了吸附等温线、回归出吸附等温方程并对化学吸附过程机理进行了探讨。研究结果表明,SrCl2-NH3工质对的吸附制冷量大,适宜太阳能或低品位余热驱动,是性能优良的工质对。

  5. Radionuclide Sensors for Subsurface Water Monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Timothy DeVol

    2006-06-30

    Contamination of the subsurface by radionuclides is a persistent and vexing problem for the Department of Energy. These radionuclides must be measured in field studies and monitoed in the long term when they cannot be removed. However, no radionuclide sensors existed for groundwater monitoring prior to this team's research under the EMSP program Detection of a and b decays from radionuclides in water is difficult due to their short ranges in condensed media.

  6. Study on transfer behavior of radionuclides from soil to plants

    Energy Technology Data Exchange (ETDEWEB)

    Morita, Shigemitsu; Watanabe, Hitoshi; Katagiri, Hiromi; Shinohara, Kunihiko [Environmental Protection Section, Environment and Safety Division, Japan Nuclear Cycle Development Institute, Tokai, Ibaraki (Japan)

    1999-03-01

    Technetium-99 (Tc-99), Iodine-129 (I-129) and Neptunium-237 (Np-237) are important radionuclides for environmental assessment around nuclear fuel cycle facilities, because they have long half-lives and relatively high mobilities in the environment. Therefore, we have studied on the determination method, distribution and behavior of such long-lived radionuclides in surface soil environment. A new analytical technique using Inductively Coupled Plasma Mass Spectrometry (ICP-MS) and Microwave Induced Plasma Mass Spectrometry (MIP-MS) were applied to the determination of long-lived radionuclides in environmental samples. The sensitivity of ICP-MS method was 10 to 100,000 times higher, and the counting time was 100 to 100,000 times shorter than the conventional radioanalytical methods. The depth profiles showed that more than 90% of Tc-99, I-129, Np-237 and Pu-239, 240 were retained in the surface layer, up to 10 cm in depth, which contained much amount of organic materials. The result suggests that the content of organic materials in soil is related to adsorption of these nuclides on soil. (author)

  7. DISCHARGES OF NATURAL RADIONUCLIDES INTO THE ENVIRONMENT DUE TO FUNCTIONING OF THE ENTERPRISES OF NON-NUCLEAR INDUSTRIES

    Directory of Open Access Journals (Sweden)

    E. P. Lisachenko

    2012-01-01

    Full Text Available In the present overview we analyze the literary data concerning discharges of natural radionuclides into the environment due to functioning of the enterprises of non-nuclear industries. We consider their quantitative characteristics of discharges, the peculiarities of the formation of radionuclide composition of discharges from various industrial branches, the information about the population exposure doses due to these discharges, as well as the possibilities of standardization of the industrial discharges of natural radionuclides

  8. Adsorption characteristics of quinoline on activated carbon fiber%活性碳纤维对水中喹啉的吸附性能

    Institute of Scientific and Technical Information of China (English)

    张培; 张小平; 方益民; 兰永辉

    2013-01-01

    The static adsorption of quinoline on activated carbon fiber (ACF) was studied. The factors effecting adsorption efficiency and behaviors such as time, quinoline does, temperature, pH and organic compound were investigated. The results show that quinoline adsorption capacity on ACF was up to 210 mg/g at higher concentration and adsorption efficiency decreased with an increase of temperature. It was found that ACF had good adsorption properties when pH<7. The presence of organic substances inhibits the sorption efficiency. The adsorption isotherms conform to Langmuir adsorption isotherm and the adsorption process fits a pseudo-second-order model. The sorption parameters Δ/f° and ΔG° were both negative, so the adsorption is spontaneous and exothermic. Scientific basis is offered for environment function material ACF using in industrial production. Based on the experimental results, dynamic adsorption experiment and treatment of coke plant wastewater is necessary. In addition, the problem of the respect such as high cost and desorption regeneration of ACF remain to be further studied.%采用活性碳纤维(activated carbon fiber,ACF)静态吸附模拟废水中的喹啉,考察了吸附时间、喹啉初始浓度、温度、pH值、有机物等对吸附速率与吸附行为的影响.结果表明,ACF对喹啉的吸附速率快,30 min内基本达到平衡,初始浓度较高时,最终吸附容量较大,达210 mg/g,低温和pH值小于7时,吸附效果较好,苯酚与喹啉产生竞争吸附,配水中的吸附行为能较好的符合Langmuir等温方程,吸附动力学符合准二级动力学模型,热力学参数△H0、△G0为负值,表明该吸附是一个自发的放热过程.本研究为环境功能材料ACF应用于工业化生产提供了理论依据,有必要在此基础上进行动态吸附实验以及实际焦化废水的吸附处理实验,同时ACF成本高及脱附再生等方面问题还有待进一步深入研究.

  9. Theoretical insight of adsorption cooling

    KAUST Repository

    Chakraborty, Anutosh

    2011-06-03

    This letter proposes and presents a thermodynamic formulation to calculate the energetic performances of an adsorption cooler as a function of pore widths and volumes of solid adsorbents. The simulated results in terms of the coefficient of performance are validated with experimental data. It is found from the present analysis that the performance of an adsorption cooling device is influenced mainly by the physical characteristics of solid adsorbents, and the characteristics energy between the adsorbent-adsorbate systems. The present study confirms that there exists a special type of silicagel having optimal physical characteristics that allows us to obtain the best performance.

  10. Modeling radionuclide migration from underground nuclear explosions

    Energy Technology Data Exchange (ETDEWEB)

    Harp, Dylan Robert [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Stauffer, Philip H. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Viswanathan, Hari S. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Karra, Satish [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Pandey, Sachin [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); O' Malley, Daniel [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Anderson, Dale [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-03-06

    The travel time of radionuclide gases to the ground surface in fracture rock depends on many complex factors. Numerical simulators are the most complete repositories of knowledge of the complex processes governing radionuclide gas migration to the ground surface allowing us to verify conceptualizations of physical processes against observations and forecast radionuclide gas travel times to the ground surface and isotopic ratios

  11. Transuranic radionuclides dispersed into the environment at accident sites, a bibliography

    Energy Technology Data Exchange (ETDEWEB)

    Stoker, A.C.; Noshkin, V.E.; Wong, K.M. [and others

    1994-07-01

    The purpose of this project was to compile a bibliography of references containing environmental transuranic radionuclide data. The authors intent was to identify those parameters affecting transuranic radionuclide transport that may be generic and those that may be dependent on chemical form and/or environmental conditions. An understanding of the unique characteristics and similarities between source terms and environmental conditions relative to transuranic radionuclide transport and cycling will provide the ability to assess and predict the long term impact on man and the environment. An additional goal of the literature review, was to extract the ranges of environmental transuranic radionuclide data from the identified references for inclusion in a data base. Related to source term, these ranges of data can be used to calculate the dose to man from the radionuclides, and to perform uncertainty analyses on these dose assessments.

  12. Chemistry and analysis of radionuclides

    CERN Document Server

    Lehto, Jukka

    2010-01-01

    Written by chemists for chemists, this is a comprehensive guide to the important radionuclides as well as techniques for their separation and analysis. It introduces readers to the important laboratory techniques and methodologies in the field, providing practical instructions on how to handle nuclear waste and radioactivity in the environment.

  13. Tumor Immunotargeting Using Innovative Radionuclides

    Directory of Open Access Journals (Sweden)

    Françoise Kraeber-Bodéré

    2015-02-01

    Full Text Available This paper reviews some aspects and recent developments in the use of antibodies to target radionuclides for tumor imaging and therapy. While radiolabeled antibodies have been considered for many years in this context, only a few have reached the level of routine clinical use. However, alternative radionuclides, with more appropriate physical properties, such as lutetium-177 or copper-67, as well as alpha-emitting radionuclides, including astatine-211, bismuth-213, actinium-225, and others are currently reviving hopes in cancer treatments, both in hematological diseases and solid tumors. At the same time, PET imaging, with short-lived radionuclides, such as gallium-68, fluorine-18 or copper-64, or long half-life ones, particularly iodine-124 and zirconium-89 now offers new perspectives in immuno-specific phenotype tumor imaging. New antibody analogues and pretargeting strategies have also considerably improved the performances of tumor immunotargeting and completely renewed the interest in these approaches for imaging and therapy by providing theranostics, companion diagnostics and news tools to make personalized medicine a reality.

  14. Radionuclide Diagnosis of Pulmonary Embolism

    DEFF Research Database (Denmark)

    Hess, Søren; Madsen, Poul Henning

    2016-01-01

    Diagnostic imaging plays an integral role in the diagnostic workup of suspected pulmonary embolism, and several modalities have been employed over the years. In recent years, the choice has been narrowed to either computer tomographic or radionuclide based methods, i.e. computer tomographic angio...

  15. The impact of oceanic circulation and phase transfer on the dispersion of radionuclides released from the Fukushima Dai-ichi Nuclear Power Plant

    Directory of Open Access Journals (Sweden)

    Y. Choi

    2013-07-01

    Full Text Available The mechanism behind the dispersion of radionuclides released from the Fukushima Dai-ichi Nuclear Power Plant on March 2011 is investigated using a numerical model. This model is a Lagrangian particle tracking–ocean circulation coupled model that is capable of solving the movement and migration of radionuclides between seawater, particulates, and bottom sediments. Model simulations show the radionuclides dispersing rapidly into the interior of the North Pacific once they enter a meso-scale eddy. However, some radionuclides also remain near the coast, with spatial distribution depending strongly on the oceanic circulation during the first month after the release. Major adsorption to bottom sediments occurs during this first month and many of these radionuclides remain on the sea floor once they are adsorbed. Model results suggest that weak offshore advection during the first month will increase the adsorption of radionuclides to bottom sediments and decelerate the dispersion to the open ocean. If vertical mixing is weak, however, fewer radionuclides reach the sea floor and adsorb to bottom sediments. More radionuclides will then quickly disperse to the open ocean.

  16. Experimental Study on Adsorption Characteristics of SO2 and NO Using Biomass-pyrolysis Chars%生物质热解焦吸附模拟烟气中SO2和NO的实验研究

    Institute of Scientific and Technical Information of China (English)

    卢平; 陆飞; 树童; 王秦超

    2012-01-01

    以麦秆、稻秆、棉花秆、玉米秆和稻壳等5种生物质原料为对象,在热解温度Tp=673~1 073 K范围内,采用快速热解和慢速热解方式制备了生物质焦,利用固定床吸附反应装置研究了焦粒粒径、热解温度、热解速率、烟气组成、吸附反应温度和生物质种类等因素对生物质焦吸附模拟烟气中SO2、NO的影响.结果表明:生物质焦对SO2的吸附效率和吸附量随着生物质焦粒径的减小而增加,但其增加趋势逐步减小.随着热解温度升高,生物质焦对SO2的吸附效率和吸附量均呈现先上升后下降的趋势.快速热解生物质焦对SO2和NO的单独吸附效率和吸附量均高于慢速热解焦.生物质焦对SO2和NO的吸附效率和吸附量均随着吸附反应温度的升高而下降.生物质焦对SO2吸附能力显著优于吸附NO的能力,模拟烟气中SO2组分对NO吸附具有显著促进作用.SO2和NO同时吸附时,WS-RP873型生物质焦对SO2的吸附量较单独吸附时减少了22.3%,但其对NO吸附量却提高了112%.在Tp=873 K快速热解条件下,各种生物质焦对SO2吸附量顺序为麦秆焦>玉米秆焦>稻秆焦>稻壳焦>棉花秆焦,对NO吸附量顺序为麦秆焦>稻秆焦>玉米秆焦>稻壳焦>棉花秆焦.%Biomass-pyrolysis chars were prepared under rapid pyrolysis and slow pyrolysis at pyrolysis temperature (Tp) of 673-1073 K from five kinds of biomass named wheat straw, rice straw, cotton stalk, maize stalk and rice husk. The effects of biomass char particle size, pyrolysis temperature, pyrolysis rate, composition of the simulated flue gas, adsorption reaction temperature, and biomass type on adsorption characteristics of SO2 and NO by using biomass-pyrolysis chars were carried out experimentally in a fixed-bed reactor. The results indicate that adsorption efficiency and adsorption capacity of SO2 over biomass-pyrolysis chars increase with decreasing the particle size of biomass chars

  17. 天然沸石对雨水中氨氮的吸附性能%Characteristics of Rain Ammonium Adsorption by Natural Clinoptilolite

    Institute of Scientific and Technical Information of China (English)

    何茂强; 王维平; 朱中竹

    2012-01-01

    Selecting two types of natural clinoptilolite with diameters of 1 -1.5 mm and 2 - 4 mm separately as experimental material, we conduct NH4+ -N adsorption isotherms experiment and adsorption kinetics experiment to explore the regularity of zeolite adsorption NH4+-N. The experimental results show that the process of NH4+-N adsorption by natural zeolite is fitted to Freundlich adsorption i-sotherm.The maximum of NH/-N adsorption by thin and thick zeolite are 5.83 mg/g and 18.375 mg/g (zeolite) ,respectively,which prove that fine zeolite' s adsorption of NH/ -N in rain is more effective than thick zeolite's. NH4+ -N adsorption of thick natural clinoptilolite corresponds to the first-order kinetics equation. The constant of reaction rate is 0.214 23 h-1 and the adsorption rate constant is 0.022 212g·m-2 · h-1.%以粒径为1 -1.5 mm和2~4mm的细、粗两种天然料发沸石为实验材料,进行氨氮吸附等温线实验和吸附动力学实验,探讨沸石对雨水中氨氮的吸附规律.结果表明,实验沸石对NH+4的吸附等温线符合Frundlich公式,且细沸石和粗沸石对氨氮吸附量的极限值分别为5.83 mg/g和18.375 mg/g;细沸石比粗沸石有更好的吸附效果;粗沸石对氨氮的吸附反应为一级反应,吸附速率常数为0.022 212g·m-2·h-1.

  18. Research on the assessment technology of the radionuclide inventory for the radioactive waste disposal(I)

    Energy Technology Data Exchange (ETDEWEB)

    Lee, K. J.; Hong, D. S.; Hwang, G. H.; Shin, J. J.; Yuk, D. S. [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of)

    2002-03-15

    Characteristics and states of management of low and intermediate level radioactive waste in site : state of management for each type of wastes, characteristics of low and intermediate level solid radioactive waste, stage of management of low and intermediate level solid radioactive waste. Survey of state of management and characteristics of low and intermediate level radioactive waste disposal facility in foreign countries : state of management of disposal facilities, classification criteria and target radionuclides for assessment in foreign disposal facilities. Survey of the assessment methods of the radionuclides inventory and establishing the direction of requirement : assessment methods of the radionuclides inventory, analysis of radionuclides assay system in KORI site, establishment the direction of requirement in the assessment methods.

  19. Sequential Extraction of Natural Surface Coatings: Comparison with Single Stage Extraction and Its Application in Investigating Adsorption Characteristics of Surface Coating Components for Metals

    Institute of Scientific and Technical Information of China (English)

    HUA Xiu-yi; LIU Xiao-xue; DONG De-ming; LI Ming; LI Yao-rui

    2012-01-01

    Multistage sequential extraction with different sequences was applied to extracting natural surface coatings(NSCs),and the results were compared with those by single stage extraction technique.The optimal sequential extraction scheme with the best performance was selected and incorporated into the method of selective extraction followed by adsorption and statistic analyses to study the adsorption parameters of Fe oxides,Mn oxides and organic matters in NSCs for Pb and Cd,to validate the applicability of the sequential extraction scheme.The Langmuir adsorption parameters of each component of surface coating estimated according to the adsorption data of single stage extraction of NSCs were all similar to those of sequential extraction of NSCs,and the maximum difference between the metal adsorption abilities of the components estimated via the two extraction techniques was only about 20%,indicating that either extraction techniques could be used.The optimal sequential extraction scheme obtained was first extracted with NH2OH·HCl,then with Na2S2O4,and finally with oxalic acid.

  20. Colloid-Associated Radionuclide Concentration Limits: ANL

    Energy Technology Data Exchange (ETDEWEB)

    C. Mertz

    2000-12-21

    The purpose and scope of this report is to describe the analysis of available colloidal data from waste form corrosion tests at Argonne National Laboratory (ANL) to extract characteristics of these colloids that can be used in modeling their contribution to the source term for sparingly soluble radioelements (e.g., Pu). Specifically, the focus is on developing a useful description of the following waste form colloid characteristics: (1) composition, (2) size distribution, and (3) quantification of the rate of waste form colloid generation. The composition and size distribution information are intended to support analysis of the potential transport of the sparingly soluble radionuclides associated with the waste form colloids. The rate of colloid generation is intended to support analysis of the waste form colloid-associated radionuclide concentrations. In addressing the above characteristics, available data are interpreted to address mechanisms controlling colloid formation and stability. This report was developed in accordance with the ''Technical Work Plan for Waste Form Degradation Process Model Report for SR'' (CRWMS M&O 2000). Because the end objective is to support the source term modeling we have organized the conclusions into two categories: (1) data analysis conclusions and (2) recommendations for colloid source term modeling. The second category is included to facilitate use of the conclusions from the data analysis in the abstraction of a colloid source term model. The data analyses and conclusions that are presented in this report are based on small-scale laboratory tests conducted on a limited number of waste glass compositions and spent fuel types.

  1. 天然和CPB改性沸石对Hg2+的吸附特征%Adsorption characteristic of mercury (Ⅱ) on natural and CPB modified zeolite

    Institute of Scientific and Technical Information of China (English)

    黄慧; 郝硕硕; 朱家亮; 申源源; 王志刚; 陈宏

    2013-01-01

    The adsorption of mercury ions on the natural zeolite and CPB modified zeolite was investigated by conducting a series of batch adsorption experiments. The adsorption kinetics, adsorption equilibrium, thermo-dynamic behavior and mechanism were discussed. Results showed that the equilibrium data of the two kinds of zeolites were well fitted with Langmuir equation. CPB modified zeolite can significantly improve the adsorption of Hg2+ . The adsorption rate of Hg2+ increased from 67.5% to 98.9% , and the adsorption capacity increased from 0. 521 mg/g to 3. 07 mg/g under the experimental conditions. Using Pseudo-first-order kinetics, Pseudo-second-order kinetics, Intraparticle diffusion and Elovich equation to simulate the process of dynamic respectively. The kinetic data correlated well with the Pseudo-second-order kinetic model, and the Intraparticle diffusion did have effect on the adsorption. Dynamics fitting, D-R equation fitting and thermodynamics research integrated suggested that both chemical and physical adsorption were existed in the adsorption of Hg + on two kinds of zeolites. The negative change in free energy ( △G0) , enthalpy ( △H0 ) and entropy ( △S0) indicated that the adsorption was spontaneous and exothermic. Low temperature made the adsorption easier.%通过静态实验研究溴代十六烷基吡啶(CPB)改性沸石和天然沸石对废水中Hg2+的吸附特性,探讨了吸附动力学、吸附平衡和吸附热力学机制.研究表明:Langmuir方程能较好地描述2种沸石对Hg2+的吸附,CPB改性沸石对Hg2+的吸附率得到显著提高.实验条件下,改性沸石对Hg2+的吸附率从67.5%提高到98.9%,吸附容量从0.521 mg/g提高到3.07 mg/g.利用准一级动力学方程、假二级动力学方程、颗粒内扩散模型和Elovich方程分别对动力学过程进行拟合,发现2种沸石对Hg2+的吸附均满足假二级动力学方程,且离子的颗粒内扩散对整个吸附过程有影响.动力学拟合、D-R方程

  2. 天然斜发沸石对水中氨氮的吸附研究%Characteristic Ammonia-Nitrogen Adsorption on Natural Clinoptilolite Zeolite

    Institute of Scientific and Technical Information of China (English)

    田震; 李奕怀; 沈娇雯; 许中平; 邴乃慈

    2013-01-01

      研究了天然斜发沸石对废水中氨氮的吸附行为,比较了pH值、温度、氨氮浓度等条件对吸附性能的影响。对沸石的吸附等温线用Langmuir和Freundlich模型分析拟合表明,其吸附等温线更符合Langmuir模型;不同pH环境和不同温度下氨氮的吸附量比较表明,适宜的pH值和较低的温度有利于沸石具有较高的吸附量,在温度低于30℃、pH在4~8的范围内,沸石的吸附性量可达2 mg·g-1以上。%The ammonin-nitrogen adsorption on natural clinoptilolite zeolite was investigated, and the adsorption properties at different condition were compared. The adsorption isothermal curve was analyzed according to the Langmuir and Freundlich models. The result showed that the ammonia-nitrogen adsorption on natural clinoptilolite is more suitable to the Langmuir model. The results at different pH value and different temperature indicated that they also have significant influence on the adsorption amount of the zeolite, when the pH value is between 4~8, the adsorption capacity is higher than 2 mg·g-1.

  3. Adsorption characteristics of ammonium exchange by zeolite and the optimal application in the tertiary treatment of coking wastewater using response surface methodology.

    Science.gov (United States)

    Zhao, Cui; Zheng, Zhongyuan; Zhang, Jing; Wen, Donghui; Tang, Xiaoyan

    2013-01-01

    Natural zeolite is a favorable NH(4)(+)-ion exchanger in the tertiary wastewater treatment. In this study, a natural Chinese zeolite was anatomized using the mercury injection method, X-ray diffraction, and scanning electron micrographs. The kinetic process of ammonium adsorption onto the zeolite was best described by the pseudo second order model; the adsorption equilibrium data fitted better to the Freundlich isotherm; and the exchange between ammonium and alkali/alkaline earth cations was in the order of Na(+) > Ca(2+) > K(+) > Mg(2+). Finally, the zeolite powder was applied for the tertiary treatment of coking wastewater, which still contained high concentration of ammonium after the secondary treatment by a sequencing batch reactor. The Box-Behnken design was used to design the experimental protocol, and the response surface methodology (RSM) was used for the optimization of adsorption factors. The RSM analysis showed the optimal adsorption factors as particle size, 0.03 mm; initial dosage of zeolite powder, 50.0 g/L; and contact time, 24 h. The highest ammonium removal rate was 75.0% predicted by the RMS. Considering settleability of the zeolite powder, the particle size of 0.25 mm was recommended in practice with a little loss of the ammonium removal: 70.9% as the RMS predicted.

  4. Radionuclide synovectomy - essentials for rheumatologists.

    Science.gov (United States)

    Chojnowski, Marek M; Felis-Giemza, Anna; Kobylecka, Małgorzata

    2016-01-01

    Radionuclide synovectomy is a minimally invasive method of treating persistent joint inflammation. It involves intra-articular injection of radioactive colloids which induce necrosis and fibrosis of hypertrophic synovial membrane. The most common indication for radiosynovectomy is rheumatoid arthritis, although patients with seronegative spondyloarthropathies, unclassified arthritis, haemophilic arthropathy and other less common arthropathies can also benefit from this method. Radiosynovectomy is safe, well tolerated and efficacious. About 70-80% of patients respond well to the therapy. However, the therapeutic effects are considerably worse in patients with co-existent osteoarthritis and advanced joint degeneration. Despite its advantages, radionuclide synovectomy is not performed as often as it could be, so greater knowledge and understanding of this method are needed. The authors present the most important facts about radiosynovectomy that may help rheumatologists in their daily clinical practice.

  5. Radionuclide behavior at underground environment

    Energy Technology Data Exchange (ETDEWEB)

    Hahn, Phil Soo; Park, Chung Kyun; Keum, Dong Kwon; Cho, Young Hwan; Kang, Moon Ja; Baik, Min Hoon; Hahn, Kyung Won; Chun, Kwan Sik; Park, Hyun Soo

    2000-03-01

    This study of radionuclide behavior at underground environment has been carried out as a part of the study of high-level waste disposal technology development. Therefore, the main objectives of this project are constructing a data-base and producing data for the safety assessment of a high-level radioactive waste, and verification of the objectivity of the assessment through characterization of the geochemical processes and experimental validation of the radionuclide migration. The various results from the this project can be applicable to the preliminary safety and performance assessments of the established disposal concept for a future high-level radioactive waste repository. Providing required data and technical basis for assessment methodologies could be a direct application of the results. In a long-term view, the results can also be utilized as a technical background for the establishment of government policy for high-level radioactive waste disposal.

  6. 洱海表层沉积物吸附磷特征%Phosphate Adsorption Characteristics on the Surface Sediments of Erhai Lake

    Institute of Scientific and Technical Information of China (English)

    何宗健; 刘文斌; 王圣瑞; 焦立新; 赵海超

    2011-01-01

    Adsorption kinetics and isotherms of phosphate on the surface sediments from Erhai Lake were determined through batch experiments, and the effect of total organic matter (TOM) and total calcium content in the sediments on the phosphate adsorption parameters were discussed. The results indicated that; 1) The process of phosphate adsorption kinetics of the surface sediments from Erhai Lake was divided into the rapid adsorption stage and the slow adsorption stage, which mainly occurred in the first 0. 5 h and from 0.5-5 h, respectively. The phosphate adsorption of all the sediments reached equilibrium within 5 h. 2) Qmax( The phosphate maximum adsorption capacity, 904.60-1420. 34 mg/kg) and MBC (maximum buffer capacity, 477. 33-2300. 95 L/kg) of the sediments in different sites of the west bank were significantly higher than those in the east bank, although EPC0 ( adsorption-desorption equilibrium concentrations, 0.015-0. 068 mg/L) in different sites showed the opposite trend. 3) The total calcium and total organic matter contents of the sediments were significantly positively correlated with Qmax and Vmax (maximum adsorption rate) , but were significantly negatively correlated with EPC0. 4) The phosphate adsorption parameters Qmax and Vmax of the surfacesediments from Erhai Lake were significantly higher, while EPC0 was lower, than the corresponding parameters of the shallow lakes in the middle and lower reaches of the Yangtze River catchment. Therefore, the high contents of total calcium and total organic matter in the sediments might account for high risk, but low amount of phosphate release in the sediments of Erhai Lake.%试验研究了洱海表层沉积物吸附礴动力学与等温吸附过程,探讨了总有机质与总钙对沉积物吸附磷参数的影响.结果表明:①洱海表层沉积物对磷的吸附动力学过程均可分为2个阶段,即快速吸附阶段和慢速吸附阶段.快速吸附阶段主要发生在0~0.5 h内,而慢

  7. [Radionuclide diagnosis of kidney calculi].

    Science.gov (United States)

    Vlakhov, N; Penkova, D

    1986-09-01

    Radionuclide investigations were conducted in 322 patients with nephrolithiasis. Unilateral calculosis was established in 46.3% of the patients, bilateral calculosis in 50.6%. The nature of changes on renograms, scintigrams and in clearance values was shown to depend on the localization of concrements, their size and the presence of concomitant infection. A conclusion has been made as to the usefulness of the methods with relation to operative treatment, especially in a bilateral localization of a pathological renal process.

  8. Chernobyl radionuclide distribution and migration.

    Science.gov (United States)

    Izrael, Yury A

    2007-11-01

    The accident at Unit No. 4 of the Chernobyl Nuclear Power Plant on 26 April 1986 presented severe challenges in radiation protection. Early activity measurements defined the contaminated areas in order to determine what persons should be evacuated on the basis of the exposure limit at that time of 100 mSv (10 rem) for accidents. The immediate definition of these areas was accomplished with specially equipped aircraft capable of measuring external gamma-exposure rate and radionuclide spectra. Over time, maps of 137Cs contamination (the most important long-lived radionuclide) have become more and more sophisticated and have been used for further determinations of the control of the consequences of the accident. About 70% of the total release of 137Cs was deposited in Belarus, the Russian Federation, and Ukraine; but there was also widespread deposition throughout the countries of Western Europe. Two atlases of contamination throughout Europe were prepared, and the Russian atlas included data on other radionuclides and on external gamma-exposure rates. The radiocesiums behaved as volatile radionuclides because of the volatility of cesium. In contrast to the typical pattern after nuclear weapons tests, 90Sr behaved only as a refractory element, as its volatile precursors krypton and rubidium had already decayed within the reactor. Nearly all of the refractory elements (strontium, plutonium, etc.) released by the accident were confined to the 30-km zone around the reactor. A proposal is made to develop a more complete atlas of 137Cs deposition from the accident that would include the entire Northern Hemisphere. Water was not an important vector of exposure to human beings following the accident.

  9. Potential Application Of Radionuclide Scaling Factors To High Level Waste Characterization

    Energy Technology Data Exchange (ETDEWEB)

    Reboul, S. H. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2013-09-30

    Production sources, radiological properties, relative solubilities in waste, and laboratory analysis techniques for the forty-five radionuclides identified in Hanford's Waste Treatment and Immobilization Plant (WTP) Feed Acceptance Data Quality Objectives (DQO) document are addressed in this report. Based on Savannah River Site (SRS) experience and waste characteristics, thirteen of the radionuclides are judged to be candidates for potential scaling in High Level Waste (HLW) based on the concentrations of other radionuclides as determined through laboratory measurements. The thirteen radionuclides conducive to potential scaling are: Ni-59, Zr-93, Nb-93m, Cd-113m, Sn-121m, Sn-126, Cs-135, Sm-151, Ra-226, Ra-228, Ac-227, Pa-231, and Th-229. The ability to scale radionuclides is useful from two primary perspectives: 1) it provides a means of checking the radionuclide concentrations that have been determined by laboratory analysis; and 2) it provides a means of estimating radionuclide concentrations in the absence of a laboratory analysis technique or when a complex laboratory analysis technique fails. Along with the rationale for identifying and applying the potential scaling factors, this report also provides examples of using the scaling factors to estimate concentrations of radionuclides in current SRS waste and into the future. Also included in the report are examples of independent laboratory analysis techniques that can be used to check results of key radionuclide analyses. Effective utilization of radionuclide scaling factors requires understanding of the applicable production sources and the chemistry of the waste. As such, the potential scaling approaches identified in this report should be assessed from the perspective of the Hanford waste before reaching a decision regarding WTP applicability.

  10. Transport and fate of radionuclides in aquatic environments--the use of ecosystem modelling for exposure assessments of nuclear facilities.

    Science.gov (United States)

    Kumblad, L; Kautsky, U; Naeslund, B

    2006-01-01

    In safety assessments of nuclear facilities, a wide range of radioactive isotopes and their potential hazard to a large assortment of organisms and ecosystem types over long time scales need to be considered. Models used for these purposes have typically employed approaches based on generic reference organisms, stylised environments and transfer functions for biological uptake exclusively based on bioconcentration factors (BCFs). These models are of non-mechanistic nature and involve no understanding of uptake and transport processes in the environment, which is a severe limitation when assessing real ecosystems. In this paper, ecosystem models are suggested as a method to include site-specific data and to facilitate the modelling of dynamic systems. An aquatic ecosystem model for the environmental transport of radionuclides is presented and discussed. With this model, driven and constrained by site-specific carbon dynamics and three radionuclide specific mechanisms: (i) radionuclide uptake by plants, (ii) excretion by animals, and (iii) adsorption to organic surfaces, it was possible to estimate the radionuclide concentrations in all components of the modelled ecosystem with only two radionuclide specific input parameters (BCF for plants and Kd). The importance of radionuclide specific mechanisms for the exposure to organisms was examined, and probabilistic and sensitivity analyses to assess the uncertainties related to ecosystem input parameters were performed. Verification of the model suggests that this model produces analogous results to empirically derived data for more than 20 different radionuclides.

  11. Radionuclide behavior in the environment

    Energy Technology Data Exchange (ETDEWEB)

    Tveten, U. (Institutt for Energiteknikk, Kjeller (Norway))

    1991-09-01

    The purpose of this report is to document the results of the following task: Review for quality and consistency the available data on measurements of initial ground contamination of Chernobyl radionuclides in various parts of Norway and subsequent concentrations of these radionuclides in various environmental media as functions of time. Utilize the data obtained to verify the existing models, or to improve them, for describing radionuclide behavior in the environment. Some of the processes standard were: migration into soil; weathering; resuspension; food-chain contamination; and loss or reconcentration by run-off. The task performed within this contract has been to use post-Chernobyl data from Norway to verify or find areas for possible improvement in the chronic exposure pathway models utilized in MACCS. Work has consisted mainly of collecting and evaluating post-Chernobyl information from Norway or other countries when relevant; but has also included experimental work performed specifically for the current task. In most connections the data available show the models and data in MACCS to be appropriate. A few areas where the data indicate that the MACCS approach is faulty or inadequate are, however, pointed out in the report. These should be examined carefully, and appropriate modifications should eventually be made. 14 refs., 12 figs., 22 tabs.

  12. 给水处理厂废弃铁铝泥对正磷酸盐的吸附特征%Characteristics of Orthophosphate Adsorption on Ferric-alum Residuals (FARs) from Drinking Water Treatment Plant

    Institute of Scientific and Technical Information of China (English)

    王昌辉; 裴元生

    2011-01-01

    以给水处理厂废弃铁铝泥(ferric-alum residuals,FARs)为载体,探究了FARs对正磷酸盐的吸附特征.ICP、SEM和XRD测试结果表明,FARs富含铁铝元素且为无定形结构.批量平衡实验法证实,FARs对正磷酸盐的吸附较符合伪二级动力学模型.在酸性环境条件下,磷的吸附效果最好,当pH值从4.6升至7.6时,磷的吸附量下降了40.13%,粒径为0.6~0.9 mm的FARs对磷的吸附量最大.Freundlich和Langmuir方程均能较好描述FARs对磷的等温吸附过程,相关系数分别为0%Batch tests have been used to investigate the characteristics of orthophosphate adsorption on ferric-alum residuals(FARs) from drinking water treatment plant.ICP,SEM and XRD analyses confirm that the FARs enriched in Fe and Al elements and presented amorphism structure.Orthophosphate sorption by the FARs can be described by the pseudo-second-order kinetics equation.Fine adsorption effects of the FARs were found under lower pH values,particularly a 40.13% drop of the adsorptive capacity from pH 4.6 to pH 7.6.The FARs with grain sizes of 0.6-0.9 mm had the highest adsorption capacity of orthophosphate.Experimental data could be better fitted by the isotherm models of Langmuir(R2=0.973 6) and Freundlich(R2=0.991 6).The maximal adsorptive capacity reached 45.45 mg·g-1 estimated from Langmuir isotherm model.Compared with other natural and industrial materials,FARs has relatively higher adsorption capacity.Under similar testing conditions,it was found that only about 10% orthophosphate could be desorbed from the FARs.Further study demonstrated that the mean energy of orthophosphate sorption on the FARs was 13.36 kJ·mol-1 and the ΔH00,ΔS00 and ΔG00,which indicated that orthophosphate sorption on the FARs was a spontaneously endothermic chemical reaction.It can be therefore highly valued that the FARs may be applied to phosphate removal from wastewater and surface water.

  13. Adsorption Rate Models for Multicomponent Adsorption Systems

    Institute of Scientific and Technical Information of China (English)

    姚春才

    2004-01-01

    Three adsorption rate models are derived for multicomponent adsorption systems under either pore diffusion or surface diffusion control. The linear driving force (LDF) model is obtained by assuming a parabolic intraparticle concentration profile. Models I and Ⅱ are obtained from the parabolic concentration layer approximation. Examples are presented to demonstrate the usage and accuracy of these models. It is shown that Model I is suitable for batch adsorption calculations and Model Ⅱ provides a good approximation in fixed-bed adsorption processes while the LDF model should not be used in batch adsorption and may be considered acceptable in fixed-bed adsorption where the parameter Ti is relatively large.

  14. 沉积物不同有机矿质复合体对磷的吸附特征影响%Effect of organo-mineral complexes on adsorption characteristic of phosphorus on sediment

    Institute of Scientific and Technical Information of China (English)

    王而力; 王嗣淇; 江明选

    2013-01-01

    采用平衡吸附法研究了西辽河沉积物不同有机矿质复合体对磷的吸附特征影响.结果表明,去除腐殖质后的沉积物对磷的吸附能力大大降低,其饱和吸附量(Γm)和吸附分配系数(k)分别只能达到原样的35.62%和9.93%,有机矿质复合体是影响磷在沉积物上吸附特征的主要因素;沉积物中的钙键有机矿质复合体对磷具有孔隙填充方式的吸附,其碳标化饱和吸附量为1157.05mg/kg,相当于原样的1.27倍;沉积物中的铁铝键有机矿质复合体在对磷吸附中发挥重要作用,其碳标化饱和吸附量可达1736.82mg/kg相当于原样的1.88倍.其吸附机制除孔隙填充方式外,还存在配位吸附;考查沉积物对磷的吸附能力不但要考虑腐殖质的含量,更要考虑腐殖质的复合形态,它也是影响沉积物对磷吸附特征的重要因素.以原样为基准,钙键有机矿质复合体、铁铝键有机矿质复合体携载的吸附态磷可分别按1.27和1.88倍进行估算.%Effect of organo-mineral complexes on adsorption characteristic of phosphorus on sediment was investigated by batch experiments of equilibrium adsorption. Results indicated that the sorption capacity on the sediment reduced dramatically after humus was removed, Normalized sorption capacity and partition coefficient only accounted for 35.62% and 9.93% of original sample, and organo-mineral complexes was a main factor in phosphorus sorption on sediment.The normalized carbon sorption capacity of Ca-bound humus was 1157.05mg/kg, which was 1.27 times of original sample, and adsorption mechanism was micro-hole function filling. The normalized carbon sorption capacity of Fe/Al-bound humus was 1736.82mg/kg, which was 1.88times of original sample, It plays an important role in phosphorus adsorption, and adsorption mechanism may be coordination adsorption apart from micro-hole function filling. Taking into account the adsorption capacity was not only organic matter

  15. Adsorption and wetting.

    NARCIS (Netherlands)

    Schlangen, L.J.M.

    1995-01-01

    Adsorption and wetting are related phenomena. In order to improve knowledge of both and their relations, experiments, thermodynamics and a theoretical interpretation have been connected, starring n-alkanes.Starting from the Gibbs adsorption equation thermodynamic relations between vapour adsorption

  16. Novel diagnostic and therapeutic radionuclides for the development of innovative radiopharmaceuticals

    CERN Multimedia

    We propose the exploration of novel radionuclides with diagnostic or therapeutic properties from ISOLDE. Access to such unique isotopes will enable the fundamental research in radiopharmaceutical science towards superior treatment, e.g. in nuclear oncology. The systematic investigation of the biological response to the different characteristics of the decay radiation will be performed for a better understanding of therapeutic effects. The development of alternative diagnostic tools will be applied for the management and optimization of radionuclide therapy.

  17. The Static Research on Adsorption Characteristics and Removal Efficiency of COD by Different Zeolite Substrates in Biogas Slurry%不同沸石材料对沼液中 COD 静态吸附去除的研究

    Institute of Scientific and Technical Information of China (English)

    邢赜; 陈玉成; 熊佰炼; 陈瑶; 常琛

    2013-01-01

    The COD was high in concentric biogas slurry which contained plenty of organic nutrients .To search for excel-lent COD adsorption substrates ,both the thermo-dynamics adsorption-desorption characteristics of COD by five common substrates (Natural zeolite(TRF),microwave-sodium chloride modified zeolite(WLF),cetylpyridinium Bromize modified zeolite(CPBF),micro-sized zeolite(WF)and submicro-sized zeolite(YWF)synthesized from coal fly ash) were illustra-ted in laboratory .The results indicated that CPBF had higher adsorption capacities and velocities of COD and lower COD desorption efficiencie than other zeolite substrates which means it could be excellent COD adsorption substrate .%集中型沼液由于含有较丰富的有机营养成分, COD 负荷较高。为了寻找高效 COD 吸附基质,以天然斜发沸石( TRF )、微波与氯化钠联合改性沸石( WLF )、CPB 改性沸石( CPBF )、微米级( WF )以及亚微米级( YWF )两种粉煤灰合成沸石为研究对象,对沼液COD 的热力学吸附解吸进行研究。结果表明,与其他4种沸石材料相比, CPBF 具有更高的 COD 吸附量和吸附速率以及更低的解吸率,因此具有较大的沼液 COD 吸附优势,是优良的吸附材料。

  18. Microbial Transformations of Actinides and Other Radionuclides

    Energy Technology Data Exchange (ETDEWEB)

    Francis,A.J.; Dodge, C. J.

    2009-01-07

    Microorganisms can affect the stability and mobility of the actinides and other radionuclides released from nuclear fuel cycle and from nuclear fuel reprocessing plants. Under appropriate conditions, microorganisms can alter the chemical speciation, solubility and sorption properties and thus could increase or decrease the concentrations of radionuclides in solution in the environment and the bioavailability. Dissolution or immobilization of radionuclides is brought about by direct enzymatic action or indirect non-enzymatic action of microorganisms. Although the physical, chemical, and geochemical processes affecting dissolution, precipitation, and mobilization of radionuclides have been extensively investigated, we have only limited information on the effects of microbial processes and biochemical mechanisms which affect the stability and mobility of radionuclides. The mechanisms of microbial transformations of the major and minor actinides U, Pu, Cm, Am, Np, the fission products and other radionuclides such as Ra, Tc, I, Cs, Sr, under aerobic and anaerobic conditions in the presence of electron donors and acceptors are reviewed.

  19. Targeted Radionuclide Therapy of Human Tumors

    Directory of Open Access Journals (Sweden)

    Sergey V. Gudkov

    2015-12-01

    Full Text Available Targeted radionuclide therapy is one of the most intensively developing directions of nuclear medicine. Unlike conventional external beam therapy, the targeted radionuclide therapy causes less collateral damage to normal tissues and allows targeted drug delivery to a clinically diagnosed neoplastic malformations, as well as metastasized cells and cellular clusters, thus providing systemic therapy of cancer. The methods of targeted radionuclide therapy are based on the use of molecular carriers of radionuclides with high affinity to antigens on the surface of tumor cells. The potential of targeted radionuclide therapy has markedly grown nowadays due to the expanded knowledge base in cancer biology, bioengineering, and radiochemistry. In this review, progress in the radionuclide therapy of hematological malignancies and approaches for treatment of solid tumors is addressed.

  20. Water-quality characteristics, including sodium-adsorption ratios, for four sites in the Powder River drainage basin, Wyoming and Montana, water years 2001-2004

    Science.gov (United States)

    Clark, Melanie L.; Mason, Jon P.

    2006-01-01

    The U.S. Geological Survey, in cooperation with the Wyoming Department of Environmental Quality, monitors streams throughout the Powder River structural basin in Wyoming and parts of Montana for potential effects of coalbed natural gas development. Specific conductance and sodium-adsorption ratios may be larger in coalbed waters than in stream waters that may receive the discharge waters. Therefore, continuous water-quality instruments for specific conductance were installed and discrete water-quality samples were collected to characterize water quality during water years 2001-2004 at four sites in the Powder River drainage basin: Powder River at Sussex, Wyoming; Crazy Woman Creek near Arvada, Wyoming; Clear Creek near Arvada, Wyoming; and Powder River at Moorhead, Montana. During water years 2001-2004, the median specific conductance of 2,270 microsiemens per centimeter at 25 degrees Celsius (?S/cm) in discrete samples from the Powder River at Sussex, Wyoming, was larger than the median specific conductance of 1,930 ?S/cm in discrete samples collected downstream from the Powder River at Moorhead, Montana. The median specific conductance was smallest in discrete samples from Clear Creek (1,180 ?S/cm), which has a dilution effect on the specific conductance for the Powder River at Moorhead, Montana. The daily mean specific conductance from continuous water-quality instruments during the irrigation season showed the same spatial pattern as specific conductance values for the discrete samples. Dissolved sodium, sodium-adsorption ratios, and dissolved solids generally showed the same spatial pattern as specific conductance. The largest median sodium concentration (274 milligrams per liter) and the largest range of sodium-adsorption ratios (3.7 to 21) were measured in discrete samples from the Powder River at Sussex, Wyoming. Median concentrations of sodium and sodium-adsorption ratios were substantially smaller in Crazy Woman Creek and Clear Creek, which tend to

  1. MIRD radionuclide data and decay schemes

    CERN Document Server

    Eckerman, Keith F

    2007-01-01

    For all physicians, scientists, and physicists working in the nuclear medicine field, the MIRD: Radionuclide Data and Decay Schemes updated edition is an essential sourcebook for radiation dosimetry and understanding the properties of radionuclides. Includes CD Table of Contents Decay schemes listed by atomic number Radioactive decay processes Serial decay schemes Decay schemes and decay tables This essential reference for nuclear medicine physicians, scientists and physicists also includes a CD with tabulations of the radionuclide data necessary for dosimetry calculations.

  2. Trace Metals in Groundwater & Vadose Zone Calcite: In Situ Containment & Stabilization of Stronthium-90 & Other Divalent Metals & Radionuclides at Arid West DOE

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Robert W

    2003-06-01

    Radionuclide and metal contaminants such as strontium-90 are present beneath U.S. Department of Energy (DOE) lands in both the groundwater (e.g., 100-N area at Hanford, WA) and vadose zone (e.g., Idaho Nuclear Technology and Engineering Center at the Idaho National Engineering and Environmental Laboratory). In situ containment and stabilization of these contaminants is a cost-effective treatment strategy. However, implementing in situ containment and stabilization approaches requires definition of the mechanisms that control contaminant sequestration. We are investigating the in situ immobilization of radionuclides or contaminant metals (e.g., strontium-90) by their facilitated co-precipitation with calcium carbonate in groundwater and vadose zone systems. Our facilitated approach, shown schematically in Figure 1, relies upon the hydrolysis of introduced urea to cause the acceleration of calcium carbonate precipitation (and trace metal co-precipitation) by increasing pH and alkalinity. Subsurface urea hydrolysis is catalyzed by the urease enzyme, which may be either introduced with the urea or produced in situ by ubiquitous subsurface urea hydrolyzing microorganisms. Because the precipitation process tends to be irreversible and many western aquifers are saturated with respect to calcite, the co-precipitated metals and radionuclides will be effectively removed from the aqueous phase over the long-term. Another advantage of the ureolysis approach is that the ammonium ions produced by the reaction can exchange with radionuclides sorbed to subsurface minerals, thereby enhancing the availability of the radionuclides for recapture in a more stable solid phase (co-precipitation rather than adsorption). Our specific research objectives include: * Elucidation of the mechanisms and rates for the release of sorbed trace metals and their subsequent sequestration by co-precipitation in calcite induced by urea hydrolysis. * Evaluation at the field scale of the influence of

  3. Adsorption characteristics, recognition properties, and preliminary application of nordihydroguaiaretic acid molecularly imprinted polymers prepared by sol-gel surface imprinting technology

    Science.gov (United States)

    Liao, Sen; Zhang, Wen; Long, Wei; Hou, Dan; Yang, Xuechun; Tan, Ni

    2016-02-01

    In this paper, a new core-shell composite of nordihydroguaiaretic acid (NDGA) molecularly imprinted polymers layer-coated silica gel (MIP@SiO2) was prepared through sol-gel technique and applied as a material for extraction of NDGA from Ephedra. It was synthesized using NDGA as the template molecule, γ-aminopropyltriethoxysilane (APTS) and methyltriethoxysilane (MTEOS) as the functional monomers, tetraethyl orthosilicate (TEOS) as the cross-linker and ethanol as the porogenic solvent in the surface of silica. The non-imprinted polymers layer-coated silica gel (NIP@SiO2) were prepared with the same procedure, but with the absence of template molecule. In addition, the optimum adsorption affinity occurred when the molar ratio of NDGA:APTS:MTEOS:TEOS was 1:6:2:80. The prepared MIP@SiO2 and NIP@SiO2 were analyzed by scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and Fourier transform-infrared spectroscopy (FT-IR). Their affinity properties to NDGA were evaluated through dynamic adsorption, static adsorption, and selective recognition experiments, and the results showed the saturated adsorption capacity of MIP@SiO2 could reach to 5.90 mg g-1, which was two times more than that of NIP@SiO2. High performance liquid chromatography (HPLC) was used to evaluate the extraction of NDGA from the medicinal plant ephedra by the above prepared materials, and the results indicated that the MIP@SiO2 had potential application in separation of the natural active component NDGA from medicinal plants.

  4. Influence of the Surface and Structural Characteristics of Activated Carbons on Adsorptive Removal of Halo-Olefinic Impurities from 1,1,1,3,3-Pentafluoropropane

    Institute of Scientific and Technical Information of China (English)

    Bo Zhang; Chuang Zhang; Mingquan Wei

    2014-01-01

    abstract Halo-olefinic impurities in 1,1,1,3,3-pentafluoropropane (HFC-245fa) product used as blowing agents, etc. could damage the human body and must be removed. Activated carbon was treated by HCl, HNO3 and NaOH, respec-tively. The adsorptive performance of unmodified and modified activated carbons for the removal of a low con-tent of 1-chloro-3,3,3-trifluoro-1-propene (HCFC-1233zd), 1,3,3,3-tetrafluoro-1-propene (HFC-1234ze), 1-chloro-1,3,3,3-tetrafluoro-1-propene (HFC-1224zb) and 2-chloro-1,3,3,3-tetrafluoro-1-propene (HFC-1224xe) halo-olefins in the 1,1,1,3,3-pentafluoropropane (HFC-245fa) product was investigated. These halo-olefinic im-purities could be substantially removed from the HFC-245fa product via the adsorption over activated carbon when the adsorption temperature was under 333 K, which can be attributed to theπ-πdispersion interactions between the halo-olefins and carbon graphite layer. The basic surface groups of activated carbon could catalyze the decomposition of HFC-245fa to form HFC-1234ze. However, the significant increase in the amount of surface acidic groups of activated carbon led to a distinct decrease of adsorption capacity due to the reduction in the mi-cropore volume of adsorbent and a decrease in the strength of theπ-πdispersive interactions between halo-olefin molecules and carbon basal. The breakthrough time of halo-olefinic impurities on activated carbon in-creased with the increase of molecular mass and the decrease of molecular symmetry.

  5. A comparative study of size-controlled worm-like amylopectin nanoparticles and spherical amylose nanoparticles: Their characteristics and the adsorption properties of polyphenols.

    Science.gov (United States)

    Qiu, Chao; Qin, Yang; Zhang, Shuangling; Xiong, Liu; Sun, Qingjie

    2016-12-15

    Polyphenols are known to have potent antioxidant capacity and other health-beneficial bioactivities. However, extremely low absorption rate of polyphenols restricts their bioactivity in vivo. Development of biopolymer nanoparticle carrier is a promising solution. For the first time, we have successfully prepared worm-like amylopectin nanoparticles (APNPs) and spherical amylose nanoparticles (AMNPs) using fractionated amylose and amylopectin from potato starch. Additionally, adsorption kinetics and adsorption isotherms of three polyphenols (procyanidins, epicatechins and catechins) on AMNPs and APNPs were investigated. We found that procyanidins, epicatechins, and catechins could bind to AMNPs at levels of up to 1.2, 1.5, and 1.4g/g, respectively, while the APNPs demonstrated higher adsorption amounts of 1.4, 4.3, and 2.2g/g, respectively. Furthermore, the particle size of polyphenol-loaded nanoparticles was not significantly changed. The results suggested that APNPs and AMNPs can be applied as an effective nanocarrier by delivering active compounds for nutraceutical and pharmaceutical industries.

  6. Introduction to radiobiology of targeted radionuclide therapy

    Directory of Open Access Journals (Sweden)

    Jean-Pierre ePOUGET

    2015-03-01

    Full Text Available During the last decades, new radionuclide-based targeted therapies have emerged as efficient tools for cancer treatment. Targeted radionuclide therapies (TRT are based on a multidisciplinary approach that involves the cooperation of specialists in several research fields. Among them, radiobiologists investigate the biological effects of ionizing radiation, specifically the molecular and cellular mechanisms involved in the radiation response. Most of the knowledge about radiation effects concerns external beam radiation therapy (EBRT and radiobiology has then strongly contributed to the development of this therapeutic approach. Similarly, radiobiology and dosimetry are also assumed to be ways for improving TRT, in particular in the therapy of solid tumors which are radioresistant. However, extrapolation of EBRT radiobiology to TRT is not straightforward. Indeed, the specific physical characteristics of TRT (heterogeneous and mixed irradiation, protracted exposure and low absorbed dose rate differ from those of conventional EBRT (homogeneous irradiation, short exposure and high absorbed dose rate, and consequently the response of irradiated tissues might be different. Therefore, specific TRT radiobiology needs to be explored. Determining dose-effect correlation is also a prerequisite for rigorous preclinical radiobiology studies because dosimetry provides the necessary referential to all TRT situations. It is required too for developing patient-tailored TRT in the clinic in order to estimate the best dose for tumor control, while protecting the healthy tissues, thereby improving therapeutic efficacy. Finally, it will allow to determine the relative contribution of targeted effects (assumed to be dose-related and non-targeted effects (assumed to be non-dose-related of ionizing radiation. However, conversely to EBRT where it is routinely used, dosimetry is still challenging in TRT. Therefore, it constitutes with radiobiology, one of the main

  7. 多种环境因子交互作用对沉积物吸附阿特拉津的影响%Characteristics of Atrazine Adsorption onto Surficial Sediments Influenced by Interaction of Various Environmental Factors

    Institute of Scientific and Technical Information of China (English)

    李鱼; 王志增; 王檬; 王倩

    2013-01-01

    采用自行研制的模拟自然水环境吸附解吸系统实验装置,运用24完全析因实验设计,研究4种环境因子(pH、离子强度、曝气强度和温度)共同作用对沉积物吸附阿特拉津的影响规律,并利用固定效应模型估算各环境因子主效应和高阶交互效应对沉积物吸附阿特拉津的贡献.结果表明:4种环境因子主效应对沉积物吸附阿特拉津的影响均较大(显著性水平0.05),其中曝气强度与离子强度促进沉积物吸附阿特拉津,温度与pH抑制沉积物吸附阿特拉津;4种环境因子的二阶交互效应对沉积物吸附阿特拉津的影响也较大(显著性水平0.05),效应估计值依次为温度×pH值=-73.53,曝气强度×pH值=-59.03,温度×离子强度=33.19,pH值×离子强度=27.55;在三阶交互作用中,仅有曝气强度×温度×pH值可促进沉积物吸附阿特拉津(显著性水平0.05).%In order to fully reveal the migration and transformation of the pesticide atrazine in natural water bodies we studied the characteristics of atrazine adsorption on the sediments influenced by a variety of environmental factors (such as pH, ionic strength, aeration rate, and temperature) via the simulation by means of self-designed natural water environment adsorption/desorption system experimental device based on 24 full factorial experimental design, and then employed the fixed effect model to analyze the contribution from the mathematical quantitative perspective about the main effects of various environmental factors and higher-order interaction effects to adsorption of atrazine on the sediments. It was found that the main effects of the four selected environmental factors (pH, ionic strength, aeration rate, and temperature) all have a significant impact (significance level of 0. 05) to atrazine adsorption on the sediments, in which the aeration rate and the ionic strength significantly promote atrazine adsorption on sediments, while the temperature and p

  8. 镁铝二元水滑石焙烧产物对酸性紫90染料的吸附性能%Adsorption Characteristics of Calcined Layered Double Hydroxides over Acid Violet 90

    Institute of Scientific and Technical Information of China (English)

    薛继龙; 倪哲明; 郑立; 王巧巧; 胥倩; 阮璐璐; 祝海涛

    2011-01-01

    研究了镁铝比为3:1的二元水滑石(1ayered double hydroxides)焙烧产物(MgAI-LDO,layered double oxide)对弱酸性染料酸性紫90(C40H27CrN8Na2O10S2,AV90)的吸附性能.X射线衍射和Fourier变换红外光谱的结果显示:由于水滑石的"结构记忆效应",在富水条件下,MgAl-LDO会吸附部分AV90阴离子进入水滑石层间,从而恢复为层状结构的MgAl-LDHs.研究结果表明:MgAl-LDO对AV90具有良好的去除效果,在298K,pH=9.7条件下,MgAI-LDO对AV90去除率高达99.7%,吸附容量为999.78mg/g.MgAl-LOO对AV90的吸附过程同时符合Langmuir和Freundlich等温吸附方程.并且是一个自发、放热的过程.动力学研究表明:该吸附动力学符合准二级动力学模型.吸附实验结果同时表明:MgAI-LDO吸附性能优于活性炭和二氧化硅等传统吸附剂,经三次回收利用的MgAl-LDO对AV90仍具有良好的吸附性能.%The adsorption characteristics of calcined layered double hydroxides with a Mg to AI mole ratio of 3:1 (MgAI-LDO, layered double oxide) were investigated to remove a weak acid dye acid violet 90(C40H27CrN8Na2O10S2, AV90). In the light of“memory effect”, MgAI-LDO is able to recover their original layered structure in an aquatic environment, after adsorption part of AV90 and CO32-(come from air) intercalated into interlayer of MgAI-LDHs, its structure was confirmed by X-ray diffraction and Fourier transform infrared spectra. The results of adsorption experiments indicate that the MgAI-LDO has a significant ability to remove AV90(500 mg·L-1) from the solution. The maximum equilibrium capacity Qe and removal rate η of AV90 are 999.78 mg/g and 99.7%,respectively. Adsorption isotherms show that the adsorption process is consistent with both Langmuir and Freundlich equations which is also spontaneous and exothermic. The kinetic model has been evaluated to fit the experimental data, and it is found that the pseudo-second-order best describes the adsorption kinetics of Mg

  9. 新疆阜康矿区煤层孔隙结构特征的氮吸附实验研究%Nitrogen adsorption experimental study on pore structure characteristics of coal seams in Xinjiang Fukang mining area

    Institute of Scientific and Technical Information of China (English)

    林海飞; 程博; 李树刚; 曾强; 张雪涛; 成连华

    2015-01-01

    为研究新疆阜康矿区主采煤层吸附孔孔隙结构特征,选取该矿区四个典型煤样,基于低温氮吸附实验绘制了煤样的吸附解吸等温线,得到煤的孔隙直径,采用BET模型和BJH模型计算了孔隙比表面积和体积等参数,分析了煤样孔隙比表面积及体积分布规律.结果表明:新疆阜康矿区煤的吸附解吸等温线回滞环很小,吸附孔以一段开口的均匀圆筒形孔为主.煤样吸附孔发育程度差别明显,导致各煤层对瓦斯吸附储存能力有所不同.各煤样孔径分布较为均衡,比表面积以过渡孔占比最大,其次为微孔及中孔;过渡孔和中孔的孔隙体积占比较大,微孔较小.煤样孔隙体积分布规律基本一致,比表面积在过渡孔和中孔范围内分布规律相同,微孔范围内分布差异较大.%To study the adsorption pore structure characteristics of main coal seam in Xinjiang Fukang mining area,four typical coal samples were selected in this mining area. Based on the experimental re-sults of low temperature nitrogen adsorption,the adsorption and desorption isotherms of coal samples were drawn,and the pore diameter is obtained. Using the BET theory and BJH theory,pore specific surface area and volume of coal samples are calculated. The distributions of pore specific surface and volume of coal samples were analyzed. The experimental results show that the adsorption and desorption isotherms of coal in Fukang mining area have very small hysteresis loop ,and most of the pores are cylin-drical with one end open. The difference of adsorption pore development degree of coal sample is obvi-ous,which causes different storage capacity of gas adsorption of coal seam. The average pore sizes of each coal sample are approximately the same. The specific surface area of transition pores accounted for the largest surface area of adsorption pore ,followed by micropore and mesopore;the volume of transition pore and mesopore accounted for the largest

  10. Models for transport and fate of carbon, nutrients and radionuclides in the aquatic ecosystem at Oeregrundsgrepen

    Energy Technology Data Exchange (ETDEWEB)

    Erichsen, Anders Christian; Moehlenberg, Flemming; Closter, Rikke Margrethe; Sandberg, Johannes (DHI, Hoersholm (Denmark))

    2010-06-15

    quasi-stationary equilibrium within the model area. The coupled ecosystem and radionuclide models were used to simulate present conditions, i.e. 2020 AD. Six radionuclides were modelled explicitly in addition to C-14. They represent a wide range of accumulation potentials and partition coefficients (K{sub d}, distribution of radionuclides between water, sediment and biota). The ecosystem and associated radionuclide model include a detailed sediment module where radionuclides can be bound by adsorption to the organic and inorganic fractions, be precipitated, be transported by resuspension and later deposited at larger depths. With the exception of radionuclides with very low particle affinity, such as Cl-35, the majority of radionuclides released in basins where they were introduced via groundwater flow remained in the sediments even after a simulation period of eight years. The spread of radionuclides with high partition coefficients for sediments from areas with groundwater flow takes place by sediment resuspension and subsequent transport and sedimentation. In the case of radionuclides with lower partition coefficients, release from the sediments to the water column followed by transport of dissolved radionuclides by currents plays a larger role. A significant result of the modelling was the quantification of the seasonal and spatial variation in radionuclide accumulation and in bioconcentration factors (BCFs) with spatial variation of BCFs often ranging 2 to 3 orders of magnitude. This variation was dominated by spatial differences in concentrations of radionuclides in water. In basins where radionuclides were introduced by groundwater flow, BCFs were typically 2-3 orders of magnitude lower than in deep basins without radionuclide release in the groundwater. In phytoplankton and grazers, bioconcentration factors (BCFs) scaled linearly to partition coefficients (Kd), underlining the fact that adsorption is an important process for radionuclide accumulation in the

  11. Adsorption dynamics and rejection characteristics of phthalic acid esters in DK nanofiltration membrane%DK型纳滤膜对水中微量邻苯二甲酸酯的吸附及截留特性

    Institute of Scientific and Technical Information of China (English)

    金叶; 吴礼光; 张林

    2014-01-01

    The-removal-of-trace-phthalic-acid-esters-(PAEs)-in-water-used-DK-nanofiltration-membrane-has-been-investigated.-The-adsorption-behavior-of-dimethyl-phthalate-(DMP),dieth-yl-phthalate-(DEP),di-n-butyl-phthalate-(DNBP)-and-di-iso-butyl-phthalate-(DIBP)-were-ana-lyzed.-Influence-of-Mw-and-logKow-of-PAEs-on-the-equilibrium-adsorption-capacity-and-rejection-characteristics-of-DK-nanofiltration-membrane-was-also-explored.-It-was-found-that-adsorption-isotherms-of-PAEs-in-DK-nanofiltration-membrane-fit-the-Freundlich-adsorption-equation-well.-The-rejection-characteristics-of-PAEs-involved-the-retention-of-adsorption-and-the-retention-of-membrane-pore-before-adsorption-reaches-saturation.-After-adsorption-reaches-saturation,the-re-jection-mechanisms-of-PAEs-could-be-described-by-pore-model,and-rejection-rate-(R)-of-DMP,-DEP,DNBP-and-DIBP-were-55%,78%,96%and-96.8%(0.5-MPa,30℃,PAEs’concen-trations-are-300μg/L),respectively.-The-results-indicated-that-the-trace-DNBP,DIBP-in-water-could-been-rejected-very-effectively-by-DK-nanofiltration-membrane.%邻苯二甲酸酯(PAEs)是一类典型的环境激素,对人体健康具有较大的危害。本文采用DK型纳滤膜去除水中微量邻苯二甲酸酯,分析了水中微量邻苯二甲酸二甲酯(DMP)、邻苯二甲酸二乙酯(DEP)、邻苯二甲酸正二丁酯(DNBP)和邻苯二甲酸异二丁酯(DIBP)等在DK型纳滤膜表面的吸附行为,考察了4种邻苯二甲酸酯的辛醇/水分配系数(logKow)和相对分子质量(Mw)对其在DK型纳滤膜表面的吸附和膜的截留特性的影响。结果表明Freundlich吸附方程能较好地描述4种邻苯二甲酸酯在DK型纳滤膜表面的动态吸附行为;DK型纳滤膜对水中微量邻苯二甲酸酯的截留特性表现为膜面吸附作用和膜孔筛分效应,吸附平衡后的截留机理取决于膜孔的筛分效应,DK型纳滤膜对DMP、DEP、DNBP、DIBP的截留率分别为55%、78%、96%和96.8%(0.5 MPa,30

  12. Influence of fracture networks on radionuclide transport from solidified waste forms

    Energy Technology Data Exchange (ETDEWEB)

    Seetharam, S.C., E-mail: suresh.seetharam@sckcen.be [Performance Assessments Unit, Institute for Environment, Health and Safety, Belgian Nuclear Research Centre (SCK CEN), Boeretang 200, B-2400 Mol (Belgium); Perko, J.; Jacques, D. [Performance Assessments Unit, Institute for Environment, Health and Safety, Belgian Nuclear Research Centre (SCK CEN), Boeretang 200, B-2400 Mol (Belgium); Mallants, D. [CSIRO Land and Water, Waite Road – Gate 4, Glen Osmond, SA 5064 (Australia)

    2014-04-01

    Highlights: • Magnitude of peak radionuclide fluxes is less sensitive to the fracture network geometry. • Time of peak radionuclide fluxes is sensitive to the fracture networks. • Uniform flow model mimics a limiting case of a porous medium with large number of fine fractures. • Effect of fracture width on radionuclide flux depends on the ratio of fracture to matrix conductivity. • Effect of increased dispersivity in fractured media does not always result in a lower peak flux for specific fracture networks due to higher concentrations adjacent to the fracture plane. - Abstract: Analysis of the effect of fractures in porous media on fluid flow and mass transport is of great interest in many fields including geotechnical, petroleum, hydrogeology and waste management. This paper presents sensitivity analyses examining the effect of various hypothetical fracture networks on the performance of a planned near surface disposal facility in terms of radionuclide transport behaviour. As it is impossible to predict the initiation and evolution of fracture networks and their characteristics in concrete structures over time scales of interest, several fracture networks have been postulated to test the sensitivity of radionuclide release from a disposal facility. Fluid flow through concrete matrix and fracture networks are modelled via Darcy's law. A single species radionuclide transport equation is employed for both matrix and fracture networks, which include the processes advection, diffusion, dispersion, sorption/desorption and radioactive decay. The sensitivity study evaluates variations in fracture network configuration and fracture width together with different sorption/desorption characteristics of radionuclides in a cement matrix, radioactive decay constants and matrix dispersivity. The effect of the fractures is illustrated via radionuclide breakthrough curves, magnitude and time of peak mass flux, cumulative mass flux and concentration profiles. For the

  13. Distribution Characteristics of Radionuclides in Soils Around Tailings Dump Sites of a Uranium Mining Field in South China%南方某铀尾矿区周边农田土壤中放射性核素的分布特征

    Institute of Scientific and Technical Information of China (English)

    姚高扬; 华恩祥; 高柏; 汪勇; 占凌之; 蒋经乾

    2015-01-01

    Uranium mining and beneficiation produces large amounts of tailings, which have become the main sources of radioactive contamination in the soil surrounding the tailings dump sites, directly or indirectly affecting human health. An investigation was performed of the soils around a uranium tailings dump site of a uranium mining field in South China, to explore distribution characteristics of radionuclides ( 238 U,226 Ra,232 Th and 40 K ) in paddy soil. Results show that the content of 238 U peaked at 40 cm in depth of a soil profile at Sampling Site No. 2, and the highest content of 238 U, 226 Ra, 232 Th and 40 K was found in the topsoil at all the other sampling sites. Moreover, within the 0-100 cm soil layer, the con-tents of radionuclides declined with soil depth gradually and the declining trend was the most obvious in the topsoil layer. The uneven distribution of radionuclides in the soil might be attributed to a variety of factors, such as human disturbance, local precipitation, soil pH, soil particle size, and horizontal distance from the dump site. Comprehensive evaluation of the radionuclides (238U, 226Ra, 232Th and 40K) in the paddy soil around the dump site was performed using the method of Nemerow′s pollution index ( NPI) as against the background values of the radionuclides in the soil of Jiangxi Province, in-dicating that the radioactive contamination in the paddy soil surrounding the uranium tailings dump site is at the hazardous level with NPI reaching 53. 45.%选取南方某铀尾矿库区周边土壤为研究对象,研究稻田土壤中放射性核素( 238 U、226 Ra、232 Th和40 K)的分布特征. 结果表明,2号点位238 U含量在土壤40 cm深处达到最大值,其余各采样点238 U、226 Ra、232 Th和40 K含量均在土壤表层达最高. 土壤0~1m深范围内,随深度增加放射性核素含量呈递减趋势,且在表层土壤下降速率更大.土壤中放射性核素含量分布不均匀可能受人为因素、当地降水量、

  14. THE ADSORPTION BEHAVIORS OF TOLUENE ON HYPERCROSSLINKED RESINS

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Investigation of the adsorption characteristics of toluene on two hypercrosslinked resins. The static and the kinetic adsorption were studied. The equilibrium adsorption date was fitted to freundlich adsorption isotherm models to evaluate the model parameters. The enthalpy, free energy, entropy are indicative of an exothermic, a spontaneous and disorter decreasing process. Experimental results show that the two adsorbents are better than the Amberlite XAD-4 for removingthe toluene in aqueous solutions.

  15. OPTIMAL BETA-RAY SHIELDING THICKNESSES FOR DIFFERENT THERAPEUTIC RADIONUCLIDES AND SHIELDING MATERIALS.

    Science.gov (United States)

    Cho, Yong In; Kim, Ja Mee; Kim, Jung Hoon

    2016-04-06

    To better understand the distribution of deposited energy of beta and gamma rays according to changes in shielding materials and thicknesses when radionuclides are used for therapeutic nuclear medicine, a simulation was conducted. The results showed that due to the physical characteristics of each therapeutic radionuclide, the thicknesses of shielding materials at which beta-ray shielding takes place varied. Additional analysis of the shielding of gamma ray was conducted for radionuclides that emit both beta and gamma rays simultaneously with results showing shielding effects proportional to the atomic number and density of the shielding materials. Also, analysis of bremsstrahlung emission after beta-ray interactions in the simulation revealed that the occurrence of bremsstrahlung was relatively lower than theoretically calculated and varied depending on different radionuclides.

  16. An SAR-compliant radionuclide inventory management system for a DOE research and development laboratory

    Energy Technology Data Exchange (ETDEWEB)

    O' Kula, K.R.; Lux, C.R.; Clements, J.A.

    2000-07-01

    The US Department of Energy Complex contains many laboratories that require inventory management and control of large stores of radionuclides. While the overall quantities of radionuclides are bounded by Authorization-Basis (AB) documents, the spatial distribution may change rapidly according to facility experimentation and storage limits. Thus, the consequences of postulated accident events may be difficult to quantify as the location of radiological species becomes uncertain. Furthermore, a situation of this nature may be compounded by management of fissile materials in the same laboratory. Although radionuclide inventory management, fissile material control, and compliance with AB limits may be handled individually, a systematic and consistent approach would be to integrate all three functions. A system with these characteristics, an upgraded Radionuclide Inventory and Administrative Control (RI-AC) System, has been implemented for the Savannah River Technology Center (SRTC) located on the Savannah River Site (SRS), and is summarized in this paper.

  17. 有机改性膨润土对铬的吸附特性研究%Study on adsorption characteristic of chromium by organic modified bentonite

    Institute of Scientific and Technical Information of China (English)

    曹福; 刘瑾

    2011-01-01

    Bentonite is modified by anionic surfactants cetyltrimethylammonium bromide in this paper. Organic bentonite is prepared through microwave dry process, and adsorption experiment of Cr( Ⅵ) in wastewater is carried out with the modified bentonite obtained. The results show that the bentonite modified by 5% mass concentration CTMAB solution has the best adsorption ability. The removal ratio of Cr( Ⅵ) can reach greater than 98% under the following condition; the dosage of modified bentonite is 1. 5 g/L, the value of pH is 4, the adsorption time is 30 mins. The organic-modified bentonite' absorption on the Cr (Ⅵ) -containing wastewater conforms to the Freundlich absorption isothermal equation.%利用阳离子表面活性剂十六烷基三甲基溴化铵(CTMAB)对膨润土进行活化改性,用微波干法制备有机膨润土,并用制备的改性膨润土对含Cr(Ⅵ)模拟废水进行吸附实验.结果表明,用5%的CTMAB溶液改性后的膨润土去除Cr(Ⅵ)效果较好,当改性膨润土用量为1.5g/L、pH值为4、搅拌30 min时,有机膨润土对含Cr(Ⅵ)废水的去除率超过98%;有机改性膨润土对含Cr (Ⅵ)废水的吸附符合Freundlich等温吸附方程.

  18. Radionuclide scintigraphy of the scrotum

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jun Hyung; Park, Young Hee; Lee, Soon Jin; Lee, Sun Wha; Ko, Young Tae; Kim, Soon Yong [Kyung Hee University College of Medicine, Seoul (Korea, Republic of)

    1984-12-15

    Radionuclide scrotal scintigraphy with {sup 99m}Tc-pertechnetate is an easy, well established, useful and readily available technique for evaluation of acute scrotum. We studied 41 cases of radionuclide scrotal scintigraphy and the results were as follows: 1. The over all diagnostic accuracy of scrotal scintigraphy was 93% (38/41 cases). 2. Scrotal scintigraphy was very useful and accurate in differential diagnosis of epididymo-orchitis and testticular torsion in patient with acute scrotal pain and swelling, while there was some limitation in differential diagnosis of hematoma from acute epididymo-orchitis or torsion. 3. Scintigraphy of epididymo-orchitis showed increased perfusion and radioactivity in the epididymis and/or testis and its diagnosis accuracy was 90% (19/21 cases). 4. Acute testicular torsion showed normal flow in perfusion and cold defect occupying affected testis in static image, while missed torsion showed slightly increased flow in perfusion image and cold defect surrounded by an uniform rim of hyperactivity (halo sign). Diagnostic accuracy of testicular torsion was 86% (6/7 cases)

  19. Study on characteristics of elemental mercury adsorption by bamboo charcoal%竹炭脱除单质汞的特性研究

    Institute of Scientific and Technical Information of China (English)

    谭增强; 邱建荣; 苏胜; 向军

    2012-01-01

    为了寻求廉价、高效的脱汞吸附剂,总结了竹炭的来源、制备方法、竹炭(BC)的性质以及竹炭的应用现状,并将其应用在燃煤大气污染物汞的脱除上.在小型燃煤烟气汞脱除实验台上和模拟烟气气氛下研究了低温下BC对汞吸附性能的影响因素.实验结果表明:BC对汞有较强的吸附能力,BC粒径减小增大了BC表面积和孔容,这有利于物理吸附脱汞;吸附剂质量与流量比值(W/F)的增加延长了汞与BC的接触时间,非常利于汞的吸附脱除;BC的脱汞效率随汞浓度的增大而降低;BC对汞的吸附脱除存在着最佳反应温度,实验发现60℃为最佳脱除温度;氧气会促进单质汞的氧化,从而进一步提高BC脱除汞的能力.%The purpose of the present study was to develop cost-effective carbon-based sorbent using commercial bamboo charcoal (BC) which was produced from renewable bamboo precursor. The source, preparation methods, properties and application status of bamboo charcoal were summarized. The adsorptive potential of BC for elemental mercury was investigated through a parametric study conducted with a bench-scale bed. The effect of temperature, W/F, initial concentration and oxygen on mercury removal were analyzed. The results show that BC has strong adsorption capacity for mercury. The decrease of particle size of BC increases its BET surface area and pore volume, which can enhance its physisorption ability for elemental mercury. The increase of W/F prolongs the residence time of elemental mercury, thus improves the removal efficiency of elemental mercury. The increase of concentration of inlet mercury decreases the removal efficiency of elemental mercury. There is a best reaction temperature for the adsorption of mercury, and 60 ℃ is found to be the optimal reaction temperature. The presence of oxygen can oxidize elemental mercury and further increase the adsorption ability for

  20. Adsorption characteristics, recognition properties, and preliminary application of nordihydroguaiaretic acid molecularly imprinted polymers prepared by sol–gel surface imprinting technology

    Energy Technology Data Exchange (ETDEWEB)

    Liao, Sen; Zhang, Wen; Long, Wei; Hou, Dan; Yang, Xuechun; Tan, Ni, E-mail: tannii@21cn.com

    2016-02-28

    Graphical abstract: - Highlights: • Nordihydroguaiaretic acid imprinted polymer with imprinting factor 2.12 was prepared for the first time through hydrogen bonding and hydrophobic interaction between the template molecules and the bifunctional monomers. • The obtained surface molecularly imprinting polymers exhibited high affinity and selectivity to the template molecules. • The prepared surface molecularly imprinted polymers were used in separation the natural active component nordihydroguaiaretic acid from medicinal plants. - Abstract: In this paper, a new core-shell composite of nordihydroguaiaretic acid (NDGA) molecularly imprinted polymers layer-coated silica gel (MIP@SiO{sub 2}) was prepared through sol–gel technique and applied as a material for extraction of NDGA from Ephedra. It was synthesized using NDGA as the template molecule, γ-aminopropyltriethoxysilane (APTS) and methyltriethoxysilane (MTEOS) as the functional monomers, tetraethyl orthosilicate (TEOS) as the cross-linker and ethanol as the porogenic solvent in the surface of silica. The non-imprinted polymers layer-coated silica gel (NIP@SiO{sub 2}) were prepared with the same procedure, but with the absence of template molecule. In addition, the optimum adsorption affinity occurred when the molar ratio of NDGA:APTS:MTEOS:TEOS was 1:6:2:80. The prepared MIP@SiO{sub 2} and NIP@SiO{sub 2} were analyzed by scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and Fourier transform-infrared spectroscopy (FT-IR). Their affinity properties to NDGA were evaluated through dynamic adsorption, static adsorption, and selective recognition experiments, and the results showed the saturated adsorption capacity of MIP@SiO{sub 2} could reach to 5.90 mg g{sup −1}, which was two times more than that of NIP@SiO{sub 2}. High performance liquid chromatography (HPLC) was used to evaluate the extraction of NDGA from the medicinal plant ephedra by the above prepared materials, and the results

  1. Entrapment of Radionuclides in Nanoparticle Compositions

    DEFF Research Database (Denmark)

    2012-01-01

    such as radionuclides,for example 61Cu and 64Cu copper isotopes. The invention further relates to a novel method for loading delivery systems, such as liposome compositions, with metal entities such as radionuclides, and the use of liposomes for targeted diagnosis and treatment of a target site, such as cancerous...

  2. 不同沸石材料对沼液中磷素静态吸附去除%Static adsorption characteristics and removal efficiency of phosphate in biogas slurry by different zeolite substrates

    Institute of Scientific and Technical Information of China (English)

    邢赜; 陈玉成; 熊佰炼; 孙晓东; 孙晓静

    2013-01-01

    The phosphate content was high in concentric biogas slurry which would cause secondary pollution if improperly disposed. To search for excellent phosphate adsorption substrates, both the thermo-dynamics adsorption-desorption characteristics of phosphate by five common substrates (natural zeolite (TRF) , microwave-sodium chloride modified zeolite ( WLF ) , cetylpyridinium bromize modified zeolite ( CPBF ) , micro-sized zeolite (WF)and submicro-sized zeolite ( YWF) synthesized from coal fly ash) and influence factors such as temperature , dosing quantity, pH which could affect the adsorption of phosphate in biogas slurry were illustrated in laboratory. The results indicated that phosphate removal efficiencies of biogas slurry had reached at 24. 24% , 22.45% ,28.56% ,48.63% ,40.22% by TRF, WLF, CPBF, YWF, WF, respectively with dosing quantity as 10 g/100 mL. In the range of 15~35℃,temperature rising was beneficial for adsorption of phosphate in biogas slurry by zeolite substrates except for CPBF. The variation of adsorption of phosphate in biogas slurry by WF and YWF was larger than that of the other zeolite substrates when pH value ranged from 3.5 to 10. 5. Both WF and YWF had higher adsorption capacities and velocities of phosphorus and lower phosphorus desorption efficiencies than other zeolite substrates which means they could be excellent phosphate adsorption substrates.%集中型沼液磷含量较高,处理不当极易造成二次污染.为了寻找高效磷吸附基质,以天然斜发沸石(TRF)、微波与氯化钠联合改性沸石(WLF)、CPB改性沸石(CPBF)、微米级(WF)及亚微米级(YWF)2种粉煤灰合成沸石为研究对象,对磷的热力学吸附解吸以及动力学进行研究,并对影响沼液中磷吸附的温度,沸石投加量、pH等因素进行探讨.结果表明,在投加量为10 g/100 mL时,TRF、WLF、CPBF、YWF、WF 5种沸石材料对实际沼液磷去除率分别达到24.24%、22.45% 、28.56%、48.63%、40.22%;在15

  3. 天然斜发沸石对氨氮的快速吸附特性研究%Study on Quick Adsorption Characteristics of Ammonia on Natural Clinoptilolite

    Institute of Scientific and Technical Information of China (English)

    李元志; 沈志强; 周岳溪; 周继红; 刘佳

    2014-01-01

    The characteristics of ammonia nitrogen adsorption on the clinoptilolite was studied by static shaking table experiment , and the effect of clinoptilolite dosage and metal cations on quick adsorption of ammonium on the clinoptilolite investigated .The results indicated that the adsorption of ammonia nitrogen on clinoptilolite was fitted well with the Langmuir isotherm , and the maximum adsorption capacity was 12.903 mg/g.The removal rate increased with the decrease of the clinoptilolite size , and the adsorption process followed the pseudo-second-order kinetics model.Ammonium cations were exchanged with Na + primarily, and then Ca2+.With the increase of ammonia nitrogen concentration and the extension of absorption time , the ratio of Na +to removed NH 4+decreased , and vice versa of Ca 2+to removed NH 4+.Clinoptilolite dosage was proportional to the ammonia nitrogen removal rate and the total metal cations released to water .With increasing dosage of the clinoptilolite , the ratio of Na +to removed NH4+increased from 1.222 to 1.383.The inhibitory effect of clinoptilolite adsorption of ammonia nitrogen was in the order of K+>Ca2+>Na +>Mg2+, when the adsorption solution was added with four cations respectively .%通过静态摇床试验研究了天然斜发沸石对氨氮的吸附特性,以及沸石投加量和外加金属阳离子对其快速吸附氨氮特性的影响。结果表明,沸石对氨氮的等温吸附过程更符合Langmuir吸附模型,其最大吸附量为12.903 mg/g;沸石粒径减小,有利于沸石对氨氮的交换吸附,不同粒径沸石对氨氮的吸附均符合准二级动力学过程;斜发沸石中与氨氮进行离子交换的阳离子主要为Na+,其次为Ca2+,随着吸附氨氮浓度的升高或吸附时间的延长,Na+与NH4+吸附去除量的比值呈下降趋势,而Ca2+的比值呈上升趋势。沸石投加量与氨氮去除率和沸石释放至水中的总金属阳离子浓度成正比,

  4. Colloidal activated carbon for in-situ groundwater remediation--Transport characteristics and adsorption of organic compounds in water-saturated sediment columns.

    Science.gov (United States)

    Georgi, Anett; Schierz, Ariette; Mackenzie, Katrin; Kopinke, Frank-Dieter

    2015-08-01

    Colloidal activated carbon can be considered as a versatile adsorbent and carrier material for in-situ groundwater remediation. In analogy to other nanoremediation approaches, activated carbon colloids (ACC) can be injected into the subsurface as aqueous suspensions. Deposition of ACC on the sediment creates a sorption barrier against further spreading of hydrophobic pollutants. This study deals with the optimization of ACC and their suspensions with a focus on suspension stability, ACC mobility in saturated porous media and sorption efficiency towards organic contaminants. ACC with an appropriate particle size range (d50=0.8μm) were obtained from a commercial powdered activated carbon product by means of wet-grinding. Among the various methods tested for stabilization of ACC suspensions, addition of humic acid (HA) and carboxymethyl cellulose (CMC) showed the best results. Due to electrosteric stabilization by adsorption of CMC, suspensions remained stable even at high ACC concentrations (11gL(-1)) and conditions typical of very hard water (5mM divalent cations). Furthermore, CMC-stabilized ACC showed high mobility in a water-saturated sandy sediment column (filter coefficient λ=0.2m(-1)). Such mobility is a pre-requisite for in-situ installation of sorption or reaction barriers by simple injection-well or direct-push application of ACC suspensions. Column experiments with organic model compounds proved the efficacy of ACC deposits on sediment for contaminant adsorption and retardation under flow-through conditions.

  5. Effect of annealing on the spectral and optical characteristics of nano ZnO: Evaluation of adsorption of toxic metal ions from industrial waste water.

    Science.gov (United States)

    Radhakrishnan, Asha; Rejani, P; Shanavas Khan, J; Beena, B

    2016-11-01

    The present work accentuates an unexploited and environmentally benign method of synthesizing ZnO nanomaterials using Sugar cane juice. The synthesized nanomaterials were characterized by XRD, SEM, TEM, BET, EDS and FTIR. UV-visible and photoluminescence studies were also carried out to understand the absorption properties of synthesized nanomaterial. From the adsorption studies, it would be clear that synthesized ZnO should be used as an effective adsorbent for Pb(ll) and Cd(ll) removal. The kinetic data followed the pseudo-second-order model. The equilibrium attained at 120min and isotherm follows the order Sips>Langmuir>Freundlich. The adsorption-desorption studies conducted over 6 cycles illustrate the viability and repeated use of the adsorbent for the removal of Pb(ll)and Cd(ll) from aqueous solutions. The practical efficiency and usefulness of the adsorbent was tested using real industrial wastewater also. Cytotoxicity result shows that, ZnO was biocompatible at lower concentrations, and it was used as an ecofriendly nanoadsorbent for industrial and environmental applications. Copyright © 2016 Elsevier Inc. All rights reserved.

  6. SALTSTONE AND RADIONUCLIDE INTERACTIONS: RADIONUCLIDE SORPTION AND DESORPTION, AND SALTSTONE REDUCTION CAPACITY

    Energy Technology Data Exchange (ETDEWEB)

    Kaplan, D; Kimberly Roberts, K; Steven Serkiz, S; Matthew Siegfried, M

    2008-10-30

    The overall objective of this study was to measure a number of key input parameters quantifying geochemical processes in the subsurface environment of the Savannah River Site's (SRS's) Saltstone Facility. For the first time, sorption (K{sub d}) values of numerous radionuclides were measured with Saltstone and Vault 2 concrete. Particular attention was directed at understanding how Tc adsorbs and desorbs from these cementitious materials with the intent to demonstrate that desorption occurs at a much slower rate than adsorption, thus permitting the use of kinetic terms instead of (or along with) the steady state K{sub d} term. Another very important parameter measured was the reduction capacity of these materials. This parameter is used to estimate the duration that the Saltstone facility remains in a reduced chemical state, a condition that maintains several otherwise mobile radionuclides in an immobile form. Key findings of this study follow. K{sub d} values for Am, Cd, Ce, Co, Cs, Hg, I, Np, Pa, Pu, Se, Sn, Tc, U, and Y for Saltstone and Vault 2 concrete were measured under oxidized and reduced conditions. Precipitation of several of the higher valence state radionuclides was observed. There was little evidence that the Vault 2 and Saltstone K{sub d} values differed from previous SRS K{sub d} values measured with reducing grout (Kaplan and Coates 2007). These values also supported a previous finding that K{sub d} values of slag-containing cementitious materials, tend to be greater for cations and about the same for anions, than regular cementitious materials without slag. Based on these new findings, it was suggested that all previous reducing concrete K{sub d} values be used in future PAs, except Np(V) and Pu(IV) K{sub d} values, which should be increased, and I values, which should be slightly decreased in all three stages of concrete aging. The reduction capacity of Saltstone, consisting of 23 wt-% blast furnace slag, was 821.8 microequivalents per

  7. Influence of high and low rank coal wettability and methane adsorption/desorption characteristics%高、低阶煤润湿性对甲烷吸附/解吸的影响

    Institute of Scientific and Technical Information of China (English)

    李沛; 马东民; 张辉; 李卫波; 杨甫

    2016-01-01

    In order to study the influence of different ranks of coal wettability on the adsorption/desorption of coalbed methane(CBM), Sihe No.3 coal and Dafosi No.4coal samples were collected, which were used to perform the contact angle measurements and adsorption/desorption experiments, and analyzed the thermal characteristics of the isosteric adsorption heat through thermodynamic calculation. The results show that the water-wettability of Dafosi No.4 coal is far better than Sihe No.3 coal resulting from Dafosi No.4 coal is low metamorphic (CY) coal and the number of oxy-gen containing functional groups such as carboxyl group, hydroxyl group and so on. Meanwhile, Dafosi No. four coal has the hydrophilic property of the material component and the advantage of the development of the pore and crack. The coal moisture content is influenced by the wettability of coal, and which indirectly influences the adsorp-tion/desorption characteristics of CBM. The relationships among wettability, moisture content, desorption rate and recovery efficiency from Dafosi No. 4 coal and Sihe No.3 coal is complicated, which is restricted by the critical water content and there is a critical point of temperature. By comparing the isosteric adsorption heat, found that the hydro-philic property of coal is not conducive to the adsorption of CBM. CBM adsorption heat release is much less than de-sorption heat absorption, there is the significant desorption hysteresis, and it decreased with increasing adsorp-tion/desorption capacity and low rank coal’s weakening trend gets more obvious.%为研究不同煤阶煤体润湿性对煤层气吸附/解吸的影响,采集寺河煤矿3号煤与大佛寺煤矿4号煤样品进行接触角测量及吸附/解吸实验,通过热力学计算分析等量吸附热特征。结果表明,大佛寺4号煤水润湿性远好于寺河3号煤,原因在于大佛寺4号煤为低变质长焰煤,其所含羧基、羟基等含氧官能团数量较多,同时具有物

  8. Modification of Natural Zeolites and their Ammonia Adsorption Characteristics%沸石的改性及其对氨氮吸附特征

    Institute of Scientific and Technical Information of China (English)

    王萌; 房春生; 颜昌宙; 魏群山; 王灶生

    2012-01-01

    为研究不同改性方法及其组合顺序对天然沸石吸附NH4+效率的影响及其吸附特征,选择盐、高温、酸3种改性方法进行不同组合.结果显示,改性组合顺序对天然沸石的吸附性能影响较明显,最佳改性组合顺序为“盐+酸+高温”,其改性后的沸石在初始ρ( NH4+)为15、30和50 mg/L下对NH4+的去除率分别为87%、92%和94%.采用Langmuir和Freundlich 2种方程来拟合“盐+酸+高温”改性后沸石的吸附行为,表明其更符合Langmuir模型,R2为0.998 5,其最大吸附量(qmax)为8.23 mg/g,并且其吸附过程符合一级动力学方程,R2为0.998 1.扫描电子显微镜(SEM)和比表面积(BET)分析结果表明,沸石经最优组合改性后表面形态明显变化,比表面积增大.%In order to investigate the impact of different modification methods and the combination of those methods on clinoptilolite adsorption of ammonia in aqueous solutions,three modification methods - salt,calcination and acid - were chosen,and they were combined in different orders. The results showed that the combination sequences clearly affected the adsorption performance of the modified zeolites. The optimal modification sequence was salt first,acid second and calcination last. With the optimal modified zeolites,the removal rates reached 87% ,92% and 94% in 15,30 and 50 mg/L ammonium solutions,respectively. The Langmuir and Freundlich equations were used to fit the adsorption behaviors of the zeolites modified by the optimal combination sequence. The results demonstrated that the Langmuir equation was better to fit the experimental data,and its maximum adsorption capacity was 8. 23 mg/g with a regression coefficient (R2) of 0. 9985. The adsorption kinetic result was fitted to the first-order equation,of which the regression coefficient (R2) reached 0. 9981. Further investigation by SEM (scanning electron microscope) and BET (brunauer,emmett and teller) showed that the zeolites modified by the

  9. Dynamic adsorption and desorption characteristics of D208 macroporous resin to heparin sodium%D208大孔径树脂对肝素钠动态吸附与解吸特性研究

    Institute of Scientific and Technical Information of China (English)

    葛庆丰; 周雷; 于海; 王捷; 汪志君

    2011-01-01

    Based on preliminary tests, D208 macroporous resin was optimized to extract heparin sodium. Dynamic adsorption and desorption characteristics of D208 macroporous resin for heparin sodium was studied to determine the best process condition for getting most heparin sodium. The results indicated that the best adsorption effect could be obtained at 2 mL · min-1 of adsorption flow rate, 6 mg · mL-1 of sample content and pH 8. 5 condition, and the optimum desorption condition was 5 bed volume 3 mol · L-1 sodium chloride solution as elution solveni, and 1 mL · min-1 of desorption flow rate, and the best desorption effect was achieved.%在前期试验基础上,以优选出的D208大孔径树脂提取、分离肝素钠,通过对D208大孔径树脂不同条件下动态吸附与解吸特性的研究,确定D208大孔径树脂提取、分离肝素钠的最佳工艺条件.结果表明:吸附流速为2 mL· min-1,上样浓度为6 mg·mL-1,上样溶液pH值为8.5,树脂对肝素钠的吸附效果最佳.用5倍柱床体积3 mol·L-1氯化钠溶液为洗脱液,洗脱速度为1 mL· min-1,洗脱效果最佳.

  10. Radionuclide imaging of spinal infections

    Energy Technology Data Exchange (ETDEWEB)

    Gemmel, Filip [Ghent Maria-Middelares, General Hospital, Division of Nuclear Medicine, Ghent (Belgium); Medical Center Leeuwarden (MCL), Division of Nuclear Medicine, Henri Dunantweg 2, Postbus 888, Leeuwarden (Netherlands); Dumarey, Nicolas [Universite Libre de Bruxelles, Hopital Erasme, Division of Nuclear Medicine, Brussels (Belgium); Palestro, Christopher J. [Long Island Jewish Medical Center, Division of Nuclear Medicine, Long Island, NY (United States)

    2006-10-15

    The diagnosis of spinal infection, with or without implants, has been a challenge for physicians for many years. Spinal infections are now being recognised more frequently, owing to aging of the population and the increasing use of spinal-fusion surgery. The diagnosis in many cases is delayed, and this may result in permanent neurological damage or even death. Laboratory evidence of infection is variable. Conventional radiography and radionuclide bone imaging lack both sensitivity and specificity. Neither in vitro labelled leucocyte scintigraphy nor {sup 99m}Tc-anti-granulocyte antibody scintigraphy is especially useful, because of the frequency with which spinal infection presents as a non-specific photopenic area on these tests. Sequential bone/gallium imaging and {sup 67}Ga-SPECT are currently the radionuclide procedures of choice for spinal osteomyelitis, but these tests lack specificity, suffer from poor spatial resolution and require several days to complete. [{sup 18}F]Fluoro-2-deoxy-D-glucose (FDG) PET is a promising technique for diagnosing spinal infection, and has several potential advantages over conventional radionuclide tests. The study is sensitive and is completed in a single session, and image quality is superior to that obtained with single-photon emitting tracers. The specificity of FDG-PET may also be superior to that of conventional tracers because degenerative bone disease and fractures usually do not produce intense FDG uptake; moreover, spinal implants do not affect FDG imaging. However, FDG-PET images have to be read with caution in patients with instrumented spinal-fusion surgery since non-specific accumulation of FDG around the fusion material is not uncommon. In the future, PET-CT will likely provide more precise localisation of abnormalities. FDG-PET may prove to be useful for monitoring response to treatment in patients with spinal osteomyelitis. Other tracers for diagnosing spinal osteomyelitis are also under investigation, including

  11. Tritium Specific Adsorption Simulation Utilizing the OSPREY Model

    Energy Technology Data Exchange (ETDEWEB)

    Veronica Rutledge; Lawrence Tavlarides; Ronghong Lin; Austin Ladshaw

    2013-09-01

    During the processing of used nuclear fuel, volatile radionuclides will be discharged to the atmosphere if no recovery processes are in place to limit their release. The volatile radionuclides of concern are 3H, 14C, 85Kr, and 129I. Methods are being developed, via adsorption and absorption unit operations, to capture these radionuclides. It is necessary to model these unit operations to aid in the evaluation of technologies and in the future development of an advanced used nuclear fuel processing plant. A collaboration between Fuel Cycle Research and Development Offgas Sigma Team member INL and a NEUP grant including ORNL, Syracuse University, and Georgia Institute of Technology has been formed to develop off gas models and support off gas research. This report is discusses the development of a tritium specific adsorption model. Using the OSPREY model and integrating it with a fundamental level isotherm model developed under and experimental data provided by the NEUP grant, the tritium specific adsorption model was developed.

  12. Does sediment resuspension by storms affect the fate of polychlorobiphenyls (PCBs) in the benthic food chain? Interactions between changes in POM characteristics, adsorption and absorption by the mussel Mytilus galloprovincialis

    Science.gov (United States)

    Charles, François; Lopez-Legentil, Susanna; Grémare, Antoine; Michel Amouroux, Jean; Desmalades, Martin; Vétion, Gilles; Escoubeyrou, Karine

    2005-12-01

    Environmental parameters and gross sedimentation rates (GSR) were monitored at a fixed site located in the Bay of Banyuls-sur-Mer (NW Mediterranean), between March 1997 and April 1998, together with the main biochemical characteristics of both sedimenting and sedimented particulate organic matter (POM). Three storms which occurred during this time period resulted in natural sediment resuspension. This is indicated by the corresponding increase in GSR and a decrease in the enzymatically hydrolysable amino acids/totally hydrolysable amino acids ratio (EHAA/THAA), within the sedimenting POM. Only the strongest storm resulted in (1) a transitory increase in fine-grained particles, (2) concomitant increases in organic carbon, carbohydrates, lipids and THAA, and (3) a decrease in the EHAA/THAA ratio in surficial sediments. For most of the assayed parameters, the values recorded after the December 1997 storm corresponded to extremes for the whole period under study. This emphasises the role of storms in controlling the characteristics of sedimented and sedimenting POM. Ten sediment types, with contrasting biochemical characteristics, were selected for experiments; these were based on the results of the monitoring survey and were used during adsorption and absorption experiments involving 14C tetrachlorobiphenyl (TCB). Adsorption rates differed significantly between the sediment types, but did not correlate with any of the assayed biochemical parameters. Absorption efficiency by the mussel Mytilus galloprovincialis also differed between the sediment types; it correlated positively with all the assayed biochemical parameters, except lipids. Comparison between the magnitudes of the increase in GSR, together with the decrease in absorption efficiency during resuspension events, suggests that resuspension tends to enhance the transfer of organic pollutants in the benthic food chain.

  13. Radionuclide Diagnosis of Pulmonary Embolism.

    Science.gov (United States)

    Hess, Søren; Madsen, Poul Henning

    2017-01-01

    Diagnostic imaging plays an integral role in the diagnostic workup of suspected pulmonary embolism, and several modalities have been employed over the years. In recent years, the choice has been narrowed to either computer tomographic or radionuclide based methods, i.e. computer tomographic angiography (CTA) and ventilation-perfusion scintigraphy (V/Q-scan). Both methods display advantages and shortcomings, and while we provide some insights into CTA and alternative methods, the paper's main focus is a review of the V/Q-scan. We discuss basic considerations, interpretation criteria, clinical value, and controversies of conventional planar lung scintigraphy as well as the more contemporary 3-dimensional imaging technique of single photon emission tomography (SPECT) with or without CT.

  14. Radionuclides in surface and groundwater

    Science.gov (United States)

    Campbell, Kate M.

    2009-01-01

    Unique among all the contaminants that adversely affect surface and water quality, radioactive compounds pose a double threat from both toxicity and damaging radiation. The extreme energy potential of many of these materials makes them both useful and toxic. The unique properties of radioactive materials make them invaluable for medical, weapons, and energy applications. However, mining, production, use, and disposal of these compounds provide potential pathways for their release into the environment, posing a risk to both humans and wildlife. This chapter discusses the sources, uses, and regulation of radioactive compounds in the United States, biogeochemical processes that control mobility in the environment, examples of radionuclide contamination, and current work related to contaminated site remediation.

  15. Airborne remote sensing of estuarine intertidal radionuclide concentrations

    Energy Technology Data Exchange (ETDEWEB)

    Rainey, M.P

    1999-08-01

    The ability to map industrial discharges through remote sensing provides a powerful tool in environmental monitoring. Radionuclide effluents have been discharged, under authorization, into the Irish Sea from BNFL (British Nuclear Fuels Pic.) sites at Sellafield and Springfields since 1952. The quantitative mapping of this anthropogenic radioactivity in estuarine intertidal zones is crucial for absolute interpretations of radionuclide transport. The spatial resolutions of traditional approaches e.g. point sampling and airborne gamma surveys are insufficient to support geomorphic interpretations of the fate of radionuclides in estuaries. The research presented in this thesis develops the use of airborne remote sensing to derive high-resolution synoptic data on the distribution of anthropogenic radionuclides in the intertidal areas of the Ribble Estuary, Lancashire, UK. From multidate surface sediment samples a significant relationship was identified between the Sellafield-derived {sup 137}Cs and {sup 241}Am and clay content (r{sup 2} = 0.93 and 0.84 respectively). Detailed in situ, and laboratory, reflectance (0.4-2.5{mu}m) experiments demonstrated that significant relationships exist between Airborne Thematic Mapper (ATM) simulated reflectance and intertidal sediment grain-size. The spectral influence of moisture on the reflectance characteristics of the intertidal area is also evident. This had substantial implications for the timing of airborne image acquisition. Low-tide Daedalus ATM imagery (Natural Environmental Research Council) was collected of the Ribble Estuary on May 30th 1997. Preprocessing and linear unmixing of the imagery allowed accurate sub-pixel determinations of sediment clay content distributions (r{sup 2} = 0.81). Subsequently, the established relationships between {sup 137}Cs and {sup 241}Am and sediment grain-size enabled the radionuclide activity distributions across the entire intertidal area (92 km{sup 2}) to be mapped at a geomorphic scale

  16. Illicit Trafficking of Natural Radionuclides

    Science.gov (United States)

    Friedrich, Steinhäusler; Lyudmila, Zaitseva

    2008-08-01

    Natural radionuclides have been subject to trafficking worldwide, involving natural uranium ore (U 238), processed uranium (yellow cake), low enriched uranium (20% U 235), radium (Ra 226), polonium (Po 210), and natural thorium ore (Th 232). An important prerequisite to successful illicit trafficking activities is access to a suitable logistical infrastructure enabling an undercover shipment of radioactive materials and, in case of trafficking natural uranium or thorium ore, capable of transporting large volumes of material. Covert en route diversion of an authorised uranium transport, together with covert diversion of uranium concentrate from an operating or closed uranium mines or mills, are subject of case studies. Such cases, involving Israel, Iran, Pakistan and Libya, have been analyzed in terms of international actors involved and methods deployed. Using international incident data contained in the Database on Nuclear Smuggling, Theft and Orphan Radiation Sources (DSTO) and international experience gained from the fight against drug trafficking, a generic Trafficking Pathway Model (TPM) is developed for trafficking of natural radionuclides. The TPM covers the complete trafficking cycle, ranging from material diversion, covert material transport, material concealment, and all associated operational procedures. The model subdivides the trafficking cycle into five phases: (1) Material diversion by insider(s) or initiation by outsider(s); (2) Covert transport; (3) Material brokerage; (4) Material sale; (5) Material delivery. An Action Plan is recommended, addressing the strengthening of the national infrastructure for material protection and accounting, development of higher standards of good governance, and needs for improving the control system deployed by customs, border guards and security forces.

  17. Targeted Radionuclide Therapy of Melanoma.

    Science.gov (United States)

    Norain, Abdullah; Dadachova, Ekaterina

    2016-05-01

    An estimated 60,000 individuals in the United States and 132,000 worldwide are yearly diagnosed with melanoma. Until recently, treatment options for patients with stages III-IV metastatic disease were limited and offered marginal, if any, improvement in overall survival. The situation changed with the introduction of B-RAF inhibitors and anti-cytotoxic T-lymphocyte antigen 4 and anti-programmed cell death protein 1 immunotherapies into the clinical practice. With only some patients responding well to the immune therapies and with very serious side effects and high costs of immunotherapy, there is still room for other approaches for the treatment of metastatic melanoma. Targeted radionuclide therapy of melanoma could be divided into the domains of radioimmunotherapy (RIT), radiolabeled peptides, and radiolabeled small molecules. RIT of melanoma is currently experiencing a renaissance with the clinical trials of alpha-emitter (213)Bi-labeled and beta-emitter (188)Rhenium-labeled monoclonal antibodies in patients with metastatic melanoma producing encouraging results. The investigation of the mechanism of efficacy of melanoma RIT points at killing of melanoma stem cells by RIT and involvement of immune system such as complement-dependent cytotoxicity. The domain of radiolabeled peptides for targeted melanoma therapy has been preclinical so far, with work concentrated on radiolabeled peptide analogues of melanocyte-stimulating hormone receptor and on melanin-binding peptides. The field of radiolabeled small molecule produced radioiodinated benzamides that cross the cellular membrane and bind to the intracellular melanin. The recent clinical trial demonstrated measurable antitumor effects and no acute or midterm toxicities. We are hopeful that the targeted radionuclide therapy of metastatic melanoma would become a clinical reality as a stand-alone therapy or in combination with the immunotherapies such as anti-PD1 programmed cell death protein 1 monoclonal antibodies

  18. Analysis Method for Permeability Characteristics of Gas-filled Coal Based on Considering Adsorption Effect%基于考虑吸附作用影响的含瓦斯煤渗透特性分析方法

    Institute of Scientific and Technical Information of China (English)

    张志刚; 胡千庭

    2015-01-01

    基于前期的实验研究成果,得出考虑吸附作用影响的瓦斯渗流方程,在此基础上,建立了钻孔稳定流动状态下的瓦斯渗流模型,并采用数学物理的方法推导出钻孔单向稳定流状态下的解析解,获得了基于考虑吸附作用影响的含瓦斯煤渗透特性分析方法,为研究钻孔瓦斯涌出规律提供了技术支撑。%A gas seepage equation with considering the adsorption effect was obtained according to the earlier experimental results, on this basis a gas seepage model under stable hole flow state was established, the analytical solution under the condition of the hole unidirectional stable flow was derived by the method of mathematical physics, and based on considering the adsorption effect, the analysis method for the permeability characteristics of gas-filled coal was obtained, all of these provided technical support for the research on gas emission law of boreholes.

  19. Adsorption Characteristics of Activated Carbon Derived from Pyrolytic Tire Char for Malachite Green%废轮胎活性炭对孔雀石绿的吸附性能研究

    Institute of Scientific and Technical Information of China (English)

    李丽; 张强年; 刘双喜; 朱坦

    2012-01-01

    Activated carbon produced from pyrolytic tire char in an industrial scale was investigated its potential ability to adsorb Malachite Green (MG) by a batch method.The effect of operation parameters,such as contact time,pH,adsorbent dosage,initial concentration,temperature,ionic strength and metal ion on the adsorption were investigated to provide more information about the adsorption characteristics of the activated pyrolytic tire char (APTC).It has shown that APTC is a potential adsorbent for MG removal.The results show that higher initial MG solution,higher initial solution pH (pH>7.0) and higher temperature are fit for the adsorption,while higher ionic strength and the presence of metal ions are unfavorable for the adsorption process.%以工业规模的废轮胎热解炭黑为原料,经过水蒸汽活化制备废轮胎活性炭,采用间歇实验法考察了废轮胎活性炭对三苯甲烷类染料孔雀石绿的吸附性能.系统考察了操作因素如接触时间、溶液pH、吸附剂用量、孔雀石绿初始浓度、离子强度、重金属离子以及温度等对吸附过程以及吸附性能的影响.结果表明,废轮胎活性炭是孔雀石绿的有效吸附剂,其吸附容量高于文献报道的相关吸附剂.吸附过程在240 min内达到平衡,与相关吸附剂的平衡时间一致;孔雀石绿初始浓度高、较高的初始溶液pH值以及升高吸附温度有利于废轮胎活性炭对孔雀石绿的吸附;而较高的溶液离子强度以及重金属离子的存在不利于孔雀石绿的吸附.

  20. Radionuclides: Accumulation and Transport in Plants.

    Science.gov (United States)

    Gupta, D K; Chatterjee, S; Datta, S; Voronina, A V; Walther, C

    Application of radioactive elements or radionuclides for anthropogenic use is a widespread phenomenon nowadays. Radionuclides undergo radioactive decays releasing ionizing radiation like gamma ray(s) and/or alpha or beta particles that can displace electrons in the living matter (like in DNA) and disturb its function. Radionuclides are highly hazardous pollutants of considerable impact on the environment, food chain and human health. Cleaning up of the contaminated environment through plants is a promising technology where the rhizosphere may play an important role. Plants belonging to the families of Brassicaceae, Papilionaceae, Caryophyllaceae, Poaceae, and Asteraceae are most important in this respect and offer the largest potential for heavy metal phytoremediation. Plants like Lactuca sativa L., Silybum marianum Gaertn., Centaurea cyanus L., Carthamus tinctorius L., Helianthus annuus and H. tuberosus are also important plants for heavy metal phytoremediation. However, transfer factors (TF) of radionuclide from soil/water to plant ([Radionuclide]plant/[Radionuclide]soil) vary widely in different plants. Rhizosphere, rhizobacteria and varied metal transporters like NRAMP, ZIP families CDF, ATPases (HMAs) family like P1B-ATPases, are involved in the radio-phytoremediation processes. This review will discuss recent advancements and potential application of plants for radionuclide removal from the environment.

  1. Modeling the adsorption of mixed gases based on pure gas adsorption properties

    Science.gov (United States)

    Tzabar, N.; Holland, H. J.; Vermeer, C. H.; ter Brake, H. J. M.

    2015-12-01

    Sorption-based Joule-Thomson (JT) cryocoolers usually operate with pure gases. A sorption-based compressor has many benefits; however, it is limited by the pressure ratios it can provide. Using a mixed-refrigerant (MR) instead of a pure refrigerant in JT cryocoolers allows working at much lower pressure ratios. Therefore, it is attractive using MRs in sorption- based cryocoolers in order to reduce one of its main limitations. The adsorption of mixed gases is usually investigated under steady-state conditions, mainly for storage and separation processes. However, the process in a sorption compressor goes through various temperatures, pressures and adsorption concentrations; therefore, it differs from the common mixed gases adsorption applications. In order to simulate the sorption process in a compressor a numerical analysis for mixed gases is developed, based on pure gas adsorption characteristics. The pure gas adsorption properties have been measured for four gases (nitrogen, methane, ethane, and propane) with Norit-RB2 activated carbon. A single adsorption model is desired to describe the adsorption of all four gases. This model is further developed to a mixed-gas adsorption model. In future work more adsorbents will be tested using these four gases and the adsorption model will be verified against experimental results of mixed-gas adsorption measurements.

  2. 磁性海泡石表面零电荷点和吸附Cd~(2+)的特性%Surface point of zero charge of magnetic sepiolite and adsorption characteristics of cadmium

    Institute of Scientific and Technical Information of China (English)

    王未平; 戴友芝; 贾明畅; 李小娜; 杜婷

    2012-01-01

    Surface point of zero charge of magnetic sepiolite and adso sepiolite were studied through inert electrolyte titration and static rption characteristics of Cd2~ onto magnetic adsorption experiment. Results showed that the point of zero charge pHpzo increased from 8.0 to 8.5 after magnetically modified. The high pH value of adsorption system contributed to adsorption of heavy metal cation Cd2~ onto magnetic sepiolite. When the pH value was above 3, the adsorbed amount of Cd2+ and the removal rate of Cd2 ~ for magnetic sepiolite increased and tended to be stable with the pH increasing. The maximum adsorption capacity was 16.10 mg.g-lCd2+ for magnetic sepiolite, which is about 3.9 times of sepiolite. The removal rate of Cd2~ was 98% for magnetic sepiolite, which is about 2.2 times of sepiolite. The adsorbed amount of Cd2~ onto magnetic sepiolite has a great relevance with ionic strength, decreasing with increasing of ionic strength. The adsorbed amount increased with reaction temperature. Langm onto magnetic sepiolite with a good fitness. importance role in adsorption mechanism of uir isotherm model was applied to describe the adsorption of Cd2~ Surface complexation and surface precipitation played the most Cd2+ onto magnetic sepiolite.%采用惰性电解质滴定法和静态吸附实验,研究了磁性海泡石表面零电荷点和吸附Cd2+特性.实验结果表明,海泡石经过磁改性后所对应的pHpzc值由8.0升高到8.5,吸附体系pH的提高,有利于对重金属阳离子Cd2+的吸附.在pH值大于3时,磁性海泡石对Cd2+吸附量和去除率随pH值的升高而增大且趋于稳定,其吸附量为16.10 mg.g-1,约为海泡石的3.9倍,去除率为98%,约为海泡石的2.2倍.磁性海泡石对Cd2+的吸附量与离子强度有较大的相关性,随离子强度的增加而减小;对Cd2+的吸附量随反应温度的升高而增加,吸附等温式符合Langmuir方程.吸附机理以表面配合吸附和表面沉淀为主.

  3. 重庆市不同功能区苔藓植物重金属含量及吸附特性研究%Heavy Metal Contents of Bryophytes and Their Adsorption Characteristics in Different Functional Zones of Chongqing

    Institute of Scientific and Technical Information of China (English)

    李进猛; 王定勇; 陈益; 刘超; 张迪男; 魏琴

    2012-01-01

    Bryophytes species in different functional zones of Chongqing were sampled to determine their heavy metal (Cu, Zn and Cd) contents, and several widely distributed species were selected to study their heavy metal adsorption characteristics. The results showed that the heavy metal contents in the bryophytes were different in different urban functional zones. The Cu, Zn and Cd contents in the industry zones were 2-3 times as high as in nature reserves. Marchantia was shown to have a very strong enrichment capacity for heavy metal ions (Cd>Zn>Cu). A significant positive correlation existed in the contents of heavy metals in Bryophytes (p><0.01). Heavy metal adsorption by the Bryophytes species studied could be well fitted by Freundlich and Temkin equations. Based on Langmuir equation, the maximum heavy metal ad sorptions were calculated. The results showed that Leucobryum had greater adsorptive capacity (4. 71 mg/ g) for Cu than other bryophytes, Marchantia had the greatest adsorptive capacity for Zn (4. 13 mg/g) and Brotherella had the greatest adsorptive capacity for Cd (4. 39 mg/g) , suggesting that Bryophytes in different functional zones of Chongqing had a good capacity of heavy metal adsorption and could be used for atmospheric heavy metal pollution monitoring.%采集了重庆不同城市功能区的主要苔藓类型,分析了其重金属(Cu,Zn和Cd)含量,并选择几种分布较广苔藓进行重金属等温吸附试验.结果表明,重庆城区苔藓中Cu,Zn和Cd三种重金属含量因所处城市功能区的不同而不同,工业园区苔藓中重金属的含量是自然保护区的2~3倍.地钱属苔藓对三种重金属的都具有较强的富集能力.对Cd的富集能力最强,其次是Zn和Cu.Cu,Zn和Cd在苔藓植物体内的含量都具有显著的正相关关系(P<0.01).几种苔藓植物对三种金属离子的等温吸附可以很好的用Freundlich和Temkin方程进行拟合.由Langmuir 方程计算苔藓植物对重金属的最大吸附量,

  4. Paving the way to personalized medicine. Production of some theragnostic radionuclides at Brookhaven National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Srivastava, S.C. [Brookhaven National Lab., Upton, NY (United States). Medical Dept.

    2011-07-01

    This paper introduces a relatively novel paradigm that involves specific individual radionuclides or radionuclide pairs that have emissions that allow pre-therapy low-dose imaging plus higher-dose therapy in the same patient. We have made an attempt to sort out and organize a number of such theragnostic radionuclides and radionuclide pairs that may potentially bring us closer to the age-long dream of personalized medicine for performing tailored low-dose molecular imaging (SPECT/CT or PET/CT) to provide the necessary pre-therapy information on biodistribution, dosimetry, the limiting or critical organ or tissue, and the maximum tolerated dose (MTD), etc. If the imaging results then warrant it, it would be possible to perform higher-dose targeted molecular therapy in the same patient with the same radiopharmaceutical. A major problem that remains yet to be fully resolved is the lack of availability, in sufficient quantities, of a majority of the best candidate theragnostic radionuclides in a no-carrier-added (NCA) form. A brief description of the recently developed new or modified methods at BNL for the production of four theragnostic radionuclides, whose nuclear, physical, and chemical characteristics seem to show great promise for personalized cancer therapy are described.

  5. Paving the way to personalized medicine: production of some theragnostic radionuclides at Brookhaven National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Srivastava S. C.

    2011-06-06

    This paper introduces a relatively novel paradigm that involves specific individual radionuclides or radionuclide pairs that have emissions that allow pre-therapy low-dose imaging plus higher-dose therapy in the same patient. We have made an attempt to sort out and organize a number of such theragnostic radionuclides and radionuclide pairs that may potentially bring us closer to the age-long dream of personalized medicine for performing tailored low-dose molecular imaging (SPECT/CT or PET/CT) to provide the necessary pre-therapy information on biodistribution, dosimetry, the limiting or critical organ or tissue, and the maximum tolerated dose (MTD), etc. If the imaging results then warrant it, it would be possible to perform higher-dose targeted molecular therapy in the same patient with the same radiopharmaceutical. A major problem that remains yet to be fully resolved is the lack of availability, in sufficient quantities, of a majority of the best candidate theragnostic radionuclides in a no-carrier-added (NCA) form. A brief description of the recently developed new or modified methods at BNL for the production of four theragnostic radionuclides, whose nuclear, physical, and chemical characteristics seem to show great promise for personalized cancer therapy are described.

  6. TRANSPORT OF RADIONUCLIDES ALONG MARINE FOODCHAIN

    Institute of Scientific and Technical Information of China (English)

    吴国斌; 余君岳; 等

    1995-01-01

    A compartment model is employed to calculate the radionuclide concentrations in the ocean currents for a nuclear accient scenario where the long-lived 137 Cs is totally discharged into the sea.The radionuclide concentrations in both the waters of Daya Bay and the adjacent south China Sea are considered.Using the concentration factors for the marine organisms:fish,crustacea and mollusca,their radionuclide concentrations are also estimated.In this way,the whole body radiation doses received by an individual due to ingestion of marine organisms from the Daya Bay and the South China Sea are calculated.

  7. 2008 LANL radionuclide air emissions report

    Energy Technology Data Exchange (ETDEWEB)

    Fuehne, David P.

    2009-06-01

    The emissions of radionuclides from Department of Energy Facilities such as Los Alamos National Laboratory (LANL) are regulated by the Amendments to the Clean Air Act of 1990, National Emissions Standards for Hazardous Air Pollutants (40 CFR 61 Subpart H). These regulations established an annual dose limit of 10 mrem to the maximally exposed member of the public attributable to emissions of radionuclides. This document describes the emissions of radionuclides from LANL and the dose calculations resulting from these emissions for calendar year 2008. This report meets the reporting requirements established in the regulations.

  8. 2009 LANL radionuclide air emissions report

    Energy Technology Data Exchange (ETDEWEB)

    Fuehne, David P.

    2010-06-01

    The emissions of radionuclides from Department of Energy Facilities such as Los Alamos National Laboratory (LANL) are regulated by the Amendments to the Clean Air Act of 1990, National Emissions Standards for Hazardous Air Pollutants (40 CFR 61 Subpart H). These regulations established an annual dose limit of 10 mrem to the maximally exposed member of the public attributable to emissions of radionuclides. This document describes the emissions of radionuclides from LANL and the dose calculations resulting from these emissions for calendar year 2009. This report meets the reporting requirements established in the regulations.

  9. 2010 LANL radionuclide air emissions report /

    Energy Technology Data Exchange (ETDEWEB)

    Fuehne, David P.

    2011-06-01

    The emissions of radionuclides from Department of Energy Facilities such as Los Alamos National Laboratory (LANL) are regulated by the Amendments to the Clean Air Act of 1990, National Emissions Standards for Hazardous Air Pollutants (40 CFR 61 Subpart H). These regulations established an annual dose limit of 10 mrem to the maximally exposed member of the public attributable to emissions of radionuclides. This document describes the emissions of radionuclides from LANL and the dose calculations resulting from these emissions for calendar year 2010. This report meets the reporting requirements established in the regulations.

  10. The enrichment behavior of natural radionuclides in pulverized oil shale-fired power plants.

    Science.gov (United States)

    Vaasma, Taavi; Kiisk, Madis; Meriste, Tõnis; Tkaczyk, Alan Henry

    2014-12-01

    The oil shale industry is the largest producer of NORM (Naturally Occurring Radioactive Material) waste in Estonia. Approximately 11-12 million tons of oil shale containing various amounts of natural radionuclides is burned annually in the Narva oil shale-fired power plants, which accounts for approximately 90% of Estonian electricity production. The radionuclide behavior characteristics change during the fuel combustion process, which redistributes the radionuclides between different ash fractions. Out of 24 operational boilers in the power plants, four use circulating fluidized bed (CFB) technology and twenty use pulverized fuel (PF) technology. Over the past decade, the PF boilers have been renovated, with the main objective to increase the efficiency of the filter systems. Between 2009 and 2012, electrostatic precipitators (ESP) in four PF energy blocks were replaced with novel integrated desulphurization technology (NID) for the efficient removal of fly ash and SO2 from flue gases. Using gamma spectrometry, activity concentrations and enrichment factors for the (238)U ((238)U, (226)Ra, (210)Pb) and (232)Th ((232)Th, (228)Ra) family radionuclides as well as (40)K were measured and analyzed in different PF boiler ash fractions. The radionuclide activity concentrations in the ash samples increased from the furnace toward the back end of the flue gas duct. The highest values in different PF boiler ash fractions were in the last field of the ESP and in the NID ash, where radionuclide enrichment factors were up to 4.2 and 3.3, respectively. The acquired and analyzed data on radionuclide activity concentrations in different PF boiler ashes (operating with an ESP and a NID system) compared to CFB boiler ashes provides an indication that changes in the fuel (oil shale) composition and boiler working parameters, as well as technological enhancements in Estonian oil shale fired power plants, have had a combined effect on the distribution patterns of natural radionuclides

  11. 沙土不同有机矿质复合体对磷的吸附特征影响%Effect of different organo-mineral complexes on adsorption characteristic of phosphorus on sandy soil

    Institute of Scientific and Technical Information of China (English)

    王而力; 王嗣淇; 王道涵

    2013-01-01

    采用平衡吸附法研究了沙土不同有机矿质复合体对磷的吸附特征影响.结果表明,去除腐殖质后的沙土对磷的吸附能力大大降低,其饱和吸附量Qm和吸附分配系数K分别只能达到原样的38.41%和7.42%,说明有机矿质复合体是影响磷在沙土上吸附特征的主要因素;钙键有机矿质复合体的碳标化饱和吸附量为388.35 mg·kg-1,相当于原样的1.51倍,在其所形成的有机矿质复合体中存在着孔隙填充方式的磷吸附;铁铝键有机矿质复合体在对磷吸附中发挥着重要作用,其碳标化饱和吸附量可达500.23 mg·kg-1,相当于原样的1.93倍,其吸附机制除孔隙填充方式外,还存在铁铝氧化物及水化氧化物对磷的配位吸附.因此,考查土壤对磷的吸附能力时不仅要考虑腐殖质的含量,更要考虑腐殖质的复合形态,它也是影响土壤对磷吸附特征的重要因素.以原样的磷饱和吸附量为基准,钙键有机矿质复合体和铁铝键有机矿质复合体携载的吸附态磷可分别按原样的1.51和1.93倍进行估算.%Effect of different organo-mineral complexes on adsorption characteristic of phosphorus on sandy soil was investigated by batch experiments of equilibrium adsorption. Results indicated that the sorption capacity on the sandy soil reduced dramatically after humus was removed. Normalized sorption capacity and partition coefficient only accounted for38.41% and 7.42% of original sample, respectively, and organo-mineral complex was a main factor in phosphorus sorption on sandy soil. Normalized carbon sorption capacity of Ca-bound complex was 388. 35mg·kg-1, which was about 1. 51 times the original sample. The sorption mechanism of phosphorus on Ca-bound complex was micro-hole function filling. In addition, Fe/Al-bound complex played an important role in phosphorus adsorption. Normalized carbon sorption capacity of Fe/Al-bound complex was 500.23 mg·kg-1 , which was about 1.93 times the

  12. Scale-Dependent Fracture-Matrix Interactions and Their Impact on Radionuclide Transport: Development of efficient particle-tracking methods

    Energy Technology Data Exchange (ETDEWEB)

    Rajaram, Harihar [University of Colorado, Boulder; Brutz, Michael [University of Colorado, Boulder; Klein, Dylan R [University of Colorado, Boulder; Mallikamas, Wasin [University of Colorado, Boulder

    2014-09-18

    Matrix Diffusion and Adsorption within a rock matrix are important mechanisms for retarding transport of radionuclides in fractured rock. Due to computational limitations and difficulties in characterizing complex subsurface systems, diffusive exchange between a fracture network and surrounding rock matrix is often modeled using simplified conceptual representations. There is significant uncertainty in “effective” parameters used in these models, such as the “effective matrix diffusivity”. Often, these parameters are estimated by fitting sparse breakthrough data, and estimated values fall outside meaningful ranges, because simplified interpretive models do not consider complex three-dimensional flow. There is limited understanding of the relationship between the effective parameters and rock mass characteristics including network structure and matrix properties. There is also evidence for an apparent scale-dependence in “effective matrix diffusion” coefficients. These observations raise questions on whether fracture-matrix interaction parameters estimated from small-scale tracer tests can be used for predicting radionuclide fate and transport at the scale of DOE field sites. High-resolution three-dimensional Discrete-Fracture-Network-Matrix (DFNM) models based on well-defined local scale transport equations can help to address some of these questions. Due to tremendous advances in computational technology over the last 10 years, DFNM modeling in relatively large domains is now feasible. The overarching objective of our research is to use DFNM modeling to improve fundamental understanding of how effective parameters in conceptual models are related to fracture network structure and matrix properties. An advanced three-dimensional DFNM model is being developed, which combines upscaled particle-tracking algorithms for fracture-matrix interaction and a parallel fracture-network flow simulator. The particle-tracking algorithms allow complexity in flow fields

  13. Adsorption of Pb(Ⅱ) on Sediment of the Dianshan Lake:Adsorption Models and Kinetics

    Institute of Scientific and Technical Information of China (English)

    黄莉桦; 孙为民

    2004-01-01

    The adsorption characteristics of Pb on sediments of the Dianshan Lake in Shanghai was studied. The results show that (1)the relationship between the amount q of apparent equilibrium adsorption and the equilibrium concentration C conforms to the Freundlich isothermal adsorption equation; (2) the adsorption and desorption of Pb on sediments are not reversible, that is, adsorption/desorption of Pb exhibits hysteresis; (3) Pb adsorption behavior is initially fast, followed by a slow reaction, and the slow reaction conforms to a reversible first-order reaction; (4) by deducing the Pb adsorption kinetics, four kinetics parameters n, k1, k2, qmax independent of C could be worked out; (5) the equilibrium parameter (K) and the free energy change (ΔG) could also be determined,and the negative values of free energy change (ΔG) indicate the spontaneous nature of the adsorption.

  14. Stability characteristics and structural properties of single- and double-walled boron-nitride nanotubes under physical adsorption of Flavin mononucleotide (FMN) in aqueous environment using molecular dynamics simulations

    Energy Technology Data Exchange (ETDEWEB)

    Ansari, R., E-mail: r_ansari@guilan.ac.ir; Ajori, S., E-mail: Shahram_ajori1366@yahoo.com; Ameri, A.

    2016-03-15

    Graphical abstract: Structural properties and stability characteristics of single- and double-walled boron-nitride nanotubes functionalized with Flavin mononucleotide (FMN) in aqueous environment are investigated employing molecular dynamics simulations. - Highlights: • Structural and buckling analysis of boron-nitride nanotubes under physical adsorption of Flavin mononucleotide (FMN). • Gyration radius increases linearly as the weight percentage of FMN increases. • Presence of water molecules results in more expansion of FMN around BNNTs. • Critical buckling force of functionalized BNNTs is higher than that of pure BNNTs. • The critical strain of functionalized BNNTs is found to be lower than that of pure ones. - Abstract: The non-cytotoxic properties of Boron-nitride nanotubes (BNNTs) and the ability of stable interaction with biomolecules make them so promising for biological applications. In this research, molecular dynamics (MD) simulations are performed to investigate the structural properties and stability characteristics of single- and double-walled BNNTs under physical adsorption of Flavin mononucleotide (FMN) in vacuum and aqueous environments. According to the simulation results, gyration radius increases by rising the weight percentage of FMN. Also, the results demonstrate that critical buckling force of functionalized BNNTs increases in vacuum. Moreover, it is observed that by increasing the weight percentage of FMN, critical force of functionalized BNNTs rises. By contrast, critical strain reduces by functionalization of BNNTs in vacuum. Considering the aqueous environment, it is observed that gyration radius and critical buckling force of functionalized BNNTs increase more considerably than those of functionalized BNNTs in vacuum, whereas the critical strains approximately remain unchanged.

  15. Natural radionuclides in meadow and pasture land in the Nordic countries

    Energy Technology Data Exchange (ETDEWEB)

    Rosen, K.; Gutierrez Villanueva, J.-L.; Sundell-Bergman, S. [Swedish Univ. of Agricultural Sciences (SLU) (Sweden)] [and others

    2012-06-15

    The amount of natural radionuclides in the environment differs between the Nordic countries as shown by previous investigations and also by this study. Agricultural areas of high natural background are predominantly found in Sweden, Southern Finland and Norway while low background areas are typical for Iceland and Denmark. Thus, this study offers possibilities for studying behaviour of natural radionuclides under different conditions such as the influence of different soil types as well as the husbandry. Furthermore the areas also enable studying environmental behaviour of radium and other natural radionuclides under seemingly steady state conditions. However, migration and accumulation of natural radionuclides in cultivated soil is complex involving various processes. Thus, a long term goal of this study was to identify the implications of some of these processes by determining the soil to plant transfer for pasture land under the different conditions that prevail in the Nordic countries. The potential health hazards due to chronic ingestion of low concentrations of naturally occurring radionuclides are fairly unknown but the results of this study may provide valuable background information for assessing these radiation risks. The aim of this project has been to gain knowledge on the status of natural radionuclides in meadow and pasture land and in grassland plants in different Nordic countries and on the transfer of these radionuclides from soil/water to man via the milk/food chain (soil- meadow/pasture grass -cow-milk). Limited data are available on the mobility and the transfer of naturally occurring radionuclides in the ecosystems of the agricultural land. In addition, information concerning the concentrations in meat and dairy products is of interest for assessing exposures of humans to natural radionuclides. Soil characteristics are known to have significant impact on the mobility and uptake of natural radionuclides. Therefore, the uptake in relation to

  16. ADSORPTION OF DYES ON ACTIVATED CARBON FIBERS

    Institute of Scientific and Technical Information of China (English)

    ChenShuixia; WuChangqing; 等

    1998-01-01

    The adsorption behavior of dyes on a variety of sisal based activated carbon fibers (SACF) has been studied in this paper. The results show that this kind of ACF has excellent adsorption capacities for some organic (dye) molecules.SACF can remove nearly all methylene blue,crystal violet,bromophenol blue and Eriochrome blue black R from water after static adsorption for 24h. at 30℃. The adsorption amounts can reach more than 400mg/g when adding 50 mg SACF into 50 ml dye solution.Under the same conditions,the adsorption amounts of xylenol orange fluorescein and Eriochrome black T wree lower.On the other hand,the adsorption amounts change along with the characteristics of adsorbents.The SACFs activated above 840℃,which have higher specific surface areas and wider pore radii,have higher adsorption amounts for the dyes.The researching results also show that the adsorption rates of dyes onto SACFs decrease by the order of methylene blue,Eriochrome blue black R and crystal violet.

  17. Adsorption of ferrous ions onto montmorillonites

    Energy Technology Data Exchange (ETDEWEB)

    Qin, Dawei, E-mail: qdw109@163.com [Qilu University of Technology, Jinan, 250353, Shandong (China); Niu, Xia [Qilu University of Technology, Jinan, 250353, Shandong (China); Qiao, Min; Liu, Gang; Li, Hongxin; Meng, Zhenxiao [Shandong SiBang pharmaceutical co., LTD, Jinan, Shandong, 250200 (China)

    2015-04-01

    Highlights: • Adsorption study of ferrous ions on montmorillonites. • Using ascorbic acid as antioxidants in adsorption process. • Fe (II)-MMT had good affinity for phosphate. - Abstract: The adsorption of Fe (II) onto montmorillonites was investigated through initial concentration, contact time, pH and temperature. During the whole adsorption process, the ascorbic acid (Vitamin C) was added as a kind of antioxidant, at the same time, deionized water (after boiling) and nitrogen protection were also used to avoid oxidation. The Fe{sup 2+}/Fe{sub total} ratio of the iron exists in the Fe-montmorillonites was found more than 95%. Two kinetic models, including pseudo-first-order and pseudo-second-order model, were used to analyze the adsorption process of Fe (II) on montmorillonites. The results of our study showed that adsorption process fitted with pseudo-second-order well. Adsorption isotherms showed that Langmuir model was better than Freundlich model. The thermodynamic parameters ΔG{sup 0} and ΔH{sup 0} were 3.696 kJ/mol and 6.689 kJ/mol (we just gave the values at 298 K), respectively. The positive values at different temperatures showed that the adsorption process was non-spontaneous and endothermic. The characteristics of materials were determined by X-ray diffraction (XRD), Fourier transform infrared (FT-IR), Surface area and porosity analyzer, Thermogravimetric analysis (TGA), Differential scanning calorimeter (DSC) and Zeta potential distribution.

  18. Preparation and Gas Adsorption of Porous Materials from Molecular Precursors

    DEFF Research Database (Denmark)

    Hu, Xinming

    ABSTRACT This thesis deals with the synthesis of porous materials and their applications in gas adsorption. The thesis consists of eight chapters as follows: The first two chapters provide a brief introduction to porous materials and gas adsorption. Chapter 1 gives an overview of construction...... and characteristics of various porous materials, including activated carbons, zeolites, metal-organic frameworks (MOFs), covalent organic frameworks (COFs), and organic porous polymers (POPs). Chapter 2 briefly introduces gas adsorption theory, such as physical and chemical adsorption, adsorption isotherms...

  19. MODELLING OF KINETICS OF FLUORINE ADSORPTION ONTO MODIFIED DIATOMITE

    Directory of Open Access Journals (Sweden)

    VEACESLAV ZELENTSOV

    2017-03-01

    Full Text Available The paper presents kinetics modelling of adsorption of fluorine onto modified diatomite, its fundamental characteristics and mathematical derivations. Three models of defluoridation kinetics were used to fit the experimental results on adsorption fluorine onto diatomite: the pseudo-first order model Lagergren, the pseudo-second order model G. McKay and H.S. Ho and intraparticle diffusion model of W.J. Weber and J.C. Morris. Kinetics studies revealed that the adsorption of fluorine followed second-order rate model, complimented by intraparticle diffusion kinetics. The adsorption mechanism of fluorine involved three stages – external surface adsorption, intraparticle diffusion and the stage of equilibrium.

  20. Radiation safety requirements for radionuclide laboratories

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-07-01

    The guide lays down the requirements for laboratories and storage rooms in which radioactive substances are used or stored as unsealed sources. In addition, some general instructions concerning work in radionuclide laboratories are set out.

  1. Long lived gamma emitting radionuclides in incense.

    Science.gov (United States)

    Alrefae, Tareq

    2013-10-01

    A study of long-lived gamma emitters in incense was performed. The incense samples originated from seven different countries, and the investigated radionuclides were Ra, Ra, and K. Gamma spectroscopy revealed the presence of all three investigated radionuclides in all samples. Interestingly, the activity concentrations revealed a clear bimodal distribution that distinguished samples that were natural incense from others that were processed incense. The activity concentrations in the latter group were found to be one order of magnitude greater than in the former group. Consequently, the estimated annual effective dose from the latter group was one order of magnitude higher than that of the former group. Nonetheless, the doses from both groups were found to be some three orders of magnitude less than the average worldwide exposure to inhaled natural radionuclides. This finding suggests the radiological safety of incense for the investigated radionuclides.

  2. Radionuclide imaging of musculoskeletal infection

    Directory of Open Access Journals (Sweden)

    Christopher J. Palestro

    2007-09-01

    Full Text Available Radionuclide imaging studies are routinely used to evaluate patients suspected of having musculoskeletal infection. Three-phase bone imaging is readily available, relatively inexpensive, and very accurate in the setting of otherwise normal bone. Labeled leukocyte imaging should be used in cases of "complicating osteomyelitis" such as prosthetic joint infection. This test also is useful in clinically unsuspected diabetic pedal osteomyelitis as well as in the neuropathic joint. It is often necessary, however, to perform complementary bone marrow imaging, to maximize the accuracy of labeled leukocyte imaging. In contrast to other regions in the skeleton, labeled leukocyte imaging is not useful for diagnosing spinal osteomyelitis. At the moment, gallium is the preferred radionuclide procedure for this condition and is a useful adjunct to magnetic resonance imaging. FDG-PET likely will play an important role in the evaluation of musculoskeletal infection, especially spinal osteomyelitis, and may replace gallium imaging for this purpose.Estudos através de imagens com o uso de radionuclídeos são rotineiramente usadas para avaliar pacientes suspeitos de terem infecção músculo-esquelética. A imagem óssea em tridimensional é facilmente avaliável, relativamente de baixo custo, e muito precisa na localização de alterações ósseas. Imagem com leucócito marcado poderia ser usada nos casos de "osteomielite com complicações" tais como infecção prostética articular. Esse teste também é útil na não suspeita clinica de osteomielite associada ao pé diabético tanto quanto nas junções neuropáticas. É sempre necessário, por outro lado, realizar imagem complementar da medula óssea para aumentar a precisão da imagem com leucócito marcado. Em contraste com outras regiões no esqueleto, imagem com leucócito marcado não é útil para diagnosticar osteomielite da coluna vertebral. Até agora, o gálio é o radionuclídeo preferido para

  3. 49 CFR 173.433 - Requirements for determining basic radionuclide values, and for the listing of radionuclides on...

    Science.gov (United States)

    2010-10-01

    ... radionuclide values, and for the listing of radionuclides on shipping papers and labels. (a) For individual radionuclides listed in the table in § 173.435 and § 173.436: (1) A1 and A2 values are given in the table in... values, and for the listing of radionuclides on shipping papers and labels. 173.433 Section...

  4. Livermore Accelerator Source for Radionuclide Science (LASRS)

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Scott [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Bleuel, Darren [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Johnson, Micah [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Rusnak, Brian [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Soltz, Ron [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Tonchev, Anton [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-05-05

    The Livermore Accelerator Source for Radionuclide Science (LASRS) will generate intense photon and neutron beams to address important gaps in the study of radionuclide science that directly impact Stockpile Stewardship, Nuclear Forensics, and Nuclear Material Detection. The co-location of MeV-scale neutral and photon sources with radiochemical analytics provides a unique facility to meet current and future challenges in nuclear security and nuclear science.

  5. Adsorption affinity of anions on metal oxyhydroxides

    Science.gov (United States)

    Pechenyuk, S. I.; Semushina, Yu. P.; Kuz'mich, L. F.

    2013-03-01

    The dependences of anion (phosphate, carbonate, sulfate, chromate, oxalate, tartrate, and citrate) adsorption affinity anions from geometric characteristics, acid-base properties, and complex forming ability are generalized. It is shown that adsorption depends on the nature of both the anions and the ionic medium and adsorbent. It is established that anions are generally grouped into the following series of adsorption affinity reduction: PO{4/3-}, CO{3/2-} > C2O{4/2-}, C(OH)(CH2)2(COO){3/3-}, (CHOH)2(COO){2/2-} > CrO{4/2-} ≫ SO{4/2-}.

  6. Migration of radionuclides through a river system

    Energy Technology Data Exchange (ETDEWEB)

    Matsunaga, Takeshi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1999-03-01

    Migration behavior of several atmospherically-derived radionuclides in a river watershed was studied. A main interest was in their relocation from the ground soil of the watershed to a downstream region through a river. Studied radionuclides are: {sup 137}Cs generated by weapon tests in the atmosphere; {sup 210}Pb and {sup 7}Be of naturally occurring radionuclides; {sup 137}Cs, {sup 90}Sr, {sup 239,240}Pu and {sup 241}Am released by the Chernobyl nuclear power plant accident. Dominance of the form in suspended solid in river water (particulate form) was qualified for the radionuclides in the Kuji river watershed. An importance of discharge in flooding was also confirmed. A historical budget analysis for weapon test derived {sup 137}Cs was presented for the Hi-i river watershed and its accompanied lake sediment (Lake Shinji). The work afforded a scheme of a fate of {sup 137}Cs after falling on the ground soil and on the lake surface. Several controlling factors, which can influence on the chemical form of radionuclides discharged to a river, were also investigated in the vicinity of the Chernobyl nuclear power plant. A special attention was paid on the association of the radionuclides with dissolved species in water. Preferential association of Pu and Am isotopes to a large molecular size of dissolved matrices, probably of humic substances, was suggested. (author)

  7. Vertical distribution of natural radionuclides in soils

    Directory of Open Access Journals (Sweden)

    Lozano J. C.

    2012-04-01

    Full Text Available Low-level alpha spectrometry techniques using semiconductor detectors (PIPS and liquid scintillation counters (LKB Quantulus 1220™ were used in order to determine the activity concentration of 238U, 232Th, 234U, 230Th, 226Ra, and 210Pb in soil samples. The soils were collected from an old disused uranium mine located in southwest Spain. The soils were selected with different levels of influence from the installation, in such a way that they had different levels of radioactive contamination. The vertical profiles in the soils (down to 40 cm depth were studied in order to evaluate the vertical distribution of the natural radionuclides. The possible contamination of subsurface waters depends strongly on vertical migration, and the transfer to plants (herbs, shrubs, and trees also will depend on the distribution of the radionuclides in the root zone. The study of the activity ratios between radionuclides belonging to the same series allowed us to assess the differing behaviour of the radionuclides involved. The vertical profiles for these radionuclides were different at each sampling point, showing the local impact of the installation. However, the profiles per point were similar for the long-lived radionuclides of the 238TJ series (238U, 234U, 230Th, and 226Ra. Also, a major disequilibrium was observed between 210Pb and 226Ra in the surface layer, due to 222Rn emanation and subsequent surface deposition of 210Pb.

  8. Radionuclide Air Emissions Report for 2012

    Energy Technology Data Exchange (ETDEWEB)

    Wahl, Linnea [Ernest Orlando Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)

    2013-05-01

    Berkeley Lab operates facilities where radionuclides are produced, handled, store d, and potentially emitted . These facilities are subject to the EPA radioactive air emission regulations in 40 CFR 61, Subpart H (EPA 1989a). Radionuclides may be emitted from stacks or vents on buildings where radionuclide production or use is authorized or they may be emitted as diffuse sources. In 2012, all Berkeley Lab sources were minor sources of radionuclides (sources resulting in a potential dose of less than 0.1 mrem/yr [0.001 mSv/yr]) . These minor sources include d about 140 stack sources and no diffuse sources . T here were no unplanned airborne radionuclide emissions from Berkeley Lab operations . Emissions from minor sources were measured by sampling or monitoring or were calculated based on quantities used, received for use, or produced during the year. Using measured and calculated emissions, and building- specific and common parameters, Laboratory personnel applied the EPA -approved computer code s, CAP88-PC and COMPLY , to calculate doses to the maximally exposed individual (MEI) at any offsite point where there is a residence, school, business, or office. Because radionuclides are used at three noncontiguous locations (the main site, Berkeley West Bio center, and Joint BioEnergy Institute), three different MEIs were identified.

  9. 大孔树脂对桑黄多糖提取液中色素的吸附与解吸特性研究%Adsorption and desorption characteristics of macroporous resins to pigments of Phellinus linteus polysaccharide extraction

    Institute of Scientific and Technical Information of China (English)

    秦俊哲; 程伟; 杜军国

    2013-01-01

    In order to select a kind of resin which is better on purification of polysaccharide extracted from the fruiting bodies of Phellinus Igniarius. Compared the effects of DA201 and other 5 kinds of macroporous resins in the proessing of decolorization and removal effects of liquid protein. On static adsorption and desorption experiments, select the DA201 resin for static adsorption kinetics and desorption characteristics, investigated the resin saturated adsorption, decolorization rate, protein removing rate and total sugar retention rate. The results show: DA201 resin showed a good effects of deproteinization and decolorization, and total sugar retention rate was high. For the specific polysaccharide extraction, flow rate at 1. 0 mL/min, DA201 resin column to make protein and pigment adsorption reached saturation, need continuous sampling 10 multiple column volume (BV) at least, distilled water and 50% ethanol elution desorption effects was suitable. DA201 resin was suitable for the decolorization of polysaccharide,In order to make full use of DA201 resin adsorption properties, the string column method can be considered in industrial production.%为了选择对桑黄多糖提取液纯化效果较好的树脂,比较了DA201等5种大孔吸附树脂对桑黄多糖提取液的脱色和除蛋白质效果.对5种树脂进行静态吸附与解吸试验,选择DA201树脂研究静态吸附动力学曲线及其解吸特性,考察树脂的饱和吸附量、脱色率、蛋白质脱除率及总糖的保留率.DA201树脂对桑黄多糖提取液中的蛋白质和色素的吸附较多,表明其脱蛋白和脱色效果较好,且多糖的回收率较高.对于特定的多糖提取液,流速1.0 mL/min,过DA201树脂柱要使蛋白质和色素达到吸附饱和,需要连续进样10多个柱床体积(BV),蒸馏水和50%乙醇洗脱解吸效果均较好.DA201树脂较适于桑黄多糖提取液的初步纯化,为了充分发挥DA201树脂的吸附性能,工业生产上可考虑采用串柱法.

  10. NO adsorption studies on silicene nanosheet: DFT investigation

    Energy Technology Data Exchange (ETDEWEB)

    Chandiramouli, R., E-mail: rcmoulii@gmail.com [School of Electrical & Electronics Engineering, SASTRA University, Tirumalaisamudram, Thanjavur 613 401 (India); Srivastava, Anurag [Advanced Materials Research Group, Computational Nanoscience & Technology Laboratory, ABV-Indian Institute of Information Technology & Management Gwalior (M.P.), Gwalior 474 015 (India); Nagarajan, V. [School of Electrical & Electronics Engineering, SASTRA University, Tirumalaisamudram, Thanjavur 613 401 (India)

    2015-10-01

    Graphical abstract: - Highlights: • The adsorption characteristics of NO on silicene nanosheets are studied using density functional theory. • The NO adsorption characteristics are studied in pristine, Al and P substituted silicene nanosheet. • NO adsorption properties depend on adsorbed energy, HOMO-LUMO gap and Mulliken charge transfer. • The substitution of P atoms in silicene nanosheet enhances the NO adsorption properties. - Abstract: The electronic properties, structural stability and nitric oxide (NO) adsorption characteristics on pristine, Al and P substituted silicene nanosheet are studied using density functional theory with B3LYP/LanL2DZ basis set. The structural stability of silicene nanostructure is discussed in terms of formation energy. The formation energy, dipole moment, point symmetry, ionization potential and electron affinity of silicene nanosheet are reported. The adsorption characteristics of NO on silicene nanosheet are explored in terms of adsorption energy, energy gap and Mulliken charge transfer. The favorable adsorption site of NO on silicene nanosheet is identified and reported. From the observations, it is inferred that the adsorption characteristics of NO are prominent on pristine and P substituted silicene nanosheet.

  11. 铀矿γ能谱测井多核素定量特征能量选择最优化计算——基于特定尺寸LaBr3(Ce)单晶的钻孔γ谱探测%Optimization Calculating on Characteristic Energy Selecting for Determining Multi -radionuclide Content in Gamma- ray Spectra- log for Uranium Mine-Detecting Gamma Spectra in Borehole Based on Specified Size LaBr3 (Ce) Crystal

    Institute of Scientific and Technical Information of China (English)

    吴永鹏; 汤彬; 程建平

    2012-01-01

    Gamma - ray spectra - log technology for uranium mine using a new LaBr3 (Ce) detector can determine contents of multi - radionuclide including uranium. In order to select the best characteristic energy in detecting effect for a target multi -radionuclide, whether a given small size Φ1.5" x2" LaBr3(Ce) crystal can get a higher relative count rate for detecting characteristic energy gamma photons is an important performance parameter. Moreover, it must be taken into account that characteristic energy peaks may overlap and be affected by Compton scattering spectra. The present work establishes a mathematical formula for calculating relative count rate for a given characteristic energy and a mathematical model for numerical modeling characteristic peak detecting efficiency in accordance with practical borehole detecting conditions, and calculates the detecting efficiency and the parameter which is related to relative count rate for candidate characteristic energies. The optimal energies are selected for determining contents of the radionuclide from uranium group, radium group and thorium series under the given detecting condition by comparing the calculating results and combining with gamma spectrum measured from borehole.%采用新型LaBr3 (Ce)探测器的铀矿γ能谱测井可实现天然产状下对铀等多核素的直接定量.为了选择探测效果最优的特征能量,选定的Φ1.5 ×2英寸LaBr3 (Ce)单晶对备选特征能量光子的探测能否获得较高的相对计数率是一个重要指标.此外,还要考虑是否存在重峰情况及受康普顿散射谱的影响程度.基于此,建立计算相对计数率的数学模型以及与实际钻孔探测条件一致的峰探测效率数值模拟计算模型,计算备选各特征能量的峰探测效率,进而求出可表征各分支相对计数率的指标,通过比较并结合实测仪器谱,分别选出了在该探测条件下对铀组、镭组和钍系核素定量分析最合适的特征能量.

  12. A model of accumulation of radionuclides in biosphere originating from groundwater contamination

    Energy Technology Data Exchange (ETDEWEB)

    Gaerdenaes, Annemieke [Swedish Univ. of Agricultural Sciences, Uppsala (Sweden). Dept. of Soil Sciences; Jansson, Per-Erik; Karlberg, Louise [Royal Inst. of Technology, Stockholm (Sweden). Dept. Land and Water Resources

    2006-03-15

    The objective of this study is to introduce a module in CoupModel describing the transport and accumulation in the biosphere of a radionuclide originating from a ground water contamination. Two model approaches describing the plant uptake of a radionuclide were included, namely passive and active uptake. Passive uptake means in this study that the root uptake rate of a radionuclide is governed by water uptake. Normal mechanism for the passive water uptake is the convective flux of water from the soil to the plant. An example of element taken up passively is Ca. Active plant uptake is in this model defined as the root uptake rate of a radionuclide that is governed by carbon assimilation i.e. photosynthesis and plant growth. The actively taken up element can for example be an element essential to plant, but not available in high enough concentration by passive uptake alone, like the major nutrients N and P or an element that very well resembles a plant nutrient, like Cs resembles K. Active uptake of trace element may occur alone or in addition to passive uptake. Normal mechanism for the active uptake is molecular diffusion from the soil solution to the roots or via any other organism living in symbiosis with the roots like the mycorrhiza. Also a model approach describing adsorption was introduced. CoupModel dynamically couples and simulates the flows of water, heat, carbon and nitrogen in the soil/plant/atmosphere system. Any number of plants may be defined and are divided into roots, leaves, stem and grain. The soil is considered in one vertical profile that may be represented into a maximum of 100 layers. The model is the windows-successor and integrated version of the DOS-models SOIL and SOILN, which have been widely used on different ecosystems and climate regions during 25 years time period. To this soil/plant/atmosphere model were introduced a module describing accumulation of a radionuclide in the biosphere originating from groundwater contamination. The

  13. National Low-Level Waste Management Program Radionuclide Report Series, Volume 17: Plutonium-239

    Energy Technology Data Exchange (ETDEWEB)

    J. P. Adams; M. L. Carboneau

    1999-03-01

    This report, Volume 17 of the National Low-Level Waste Management Program Radionuclide Report Series, discusses the radiological and chemical characteristics of plutonium-239 (Pu-239). This report also discusses waste types and forms in which Pu-239 can be found, waste and disposal information on Pu-239, and Pu-239 behavior in the environment and in the human body.

  14. National Low-Level Waste Management Program radionuclide report series. Volume 13, Curium-242

    Energy Technology Data Exchange (ETDEWEB)

    Adams, J.P.

    1995-08-01

    This report, Volume 13 of the National Low-Level Waste Management Program Radionuclide Report Series, discusses the radiological and chemical characteristics of curium-242 ({sup 242}Cm). This report also includes discussions about waste types and forms in which {sup 242}Cm can be found and {sup 242}Cm behavior in the environment and in the human body.

  15. National Low-Level Waste Management Program Radionuclide Report Series. Volume 3, Carbon-14

    Energy Technology Data Exchange (ETDEWEB)

    Rudin, M.J.; Garcia, R.S.

    1992-02-01

    This report, Volume 3 of the National Low-Level Radioactive Waste Management Program Radionuclide Report Series, discusses the radiological and chemical characteristics of carbon-14. The report also discusses waste streams that contain carbon-14, waste forms that contain carbon-14, and carbon-14 behavior in the environment and in the human body.

  16. National Low-Level Waste Management Program Radionuclide Report Series. Volume 2, Technetium-99

    Energy Technology Data Exchange (ETDEWEB)

    Rudin, M.J.; Stanton, C.; Patterson, R.G.; Garcia, R.S.

    1992-02-01

    This report, Volume 2 of the National Low-Level Radioactive Waste Management Program Radionuclide Report Series, discusses radiological and chemical characteristics of technetium-99. This report also includes discussions about waste streams in which technetium-99 can be found, waste forms that contain technetium-99, and technetium-99`s behavior in the environment and in the human body.

  17. National Low-Level Waste Management Program Radionuclide Report Series. Volume 4, Iodine-129

    Energy Technology Data Exchange (ETDEWEB)

    Rudin, M.J.; Garcia, R.S.

    1992-02-01

    This report, Volume 4 of the National Low-Level Radioactive Waste Management Program Radionuclide Report Series, discusses radiological and chemical characteristics about iodine-129. This report also includes discussions about waste streams that contain iodine-129, waste forms that contain iodine-129, and iodine-129`s behavior in the environment, as well as in the human body.

  18. National low-level waste management program radionuclide report series, Volume 14: Americium-241

    Energy Technology Data Exchange (ETDEWEB)

    Winberg, M.R.; Garcia, R.S.

    1995-09-01

    This report, Volume 14 of the National Low-Level Waste Management Program Radionuclide Report Series, discusses the radiological and chemical characteristics of americium-241 ({sup 241}Am). This report also includes discussions about waste types and forms in which {sup 241}Am can be found and {sup 241}Am behavior in the environment and in the human body.

  19. Effects of humic acid on adsorption of actinide elements on rocks and others

    Energy Technology Data Exchange (ETDEWEB)

    Ohashi, Masakazu; Sato, Seichi; Ohashi, Hiroshi [Hokkaido Univ., Sapporo (Japan). Faculty of Engineering; Sakamoto, Yoshiaki; Nagao, Seiya; Onuki, Toshihiko; Senoo, Muneaki

    1996-01-01

    Since the transfer rates of radionuclides are reduced by their adsorption to rocks and soils, it is essential to elucidate the adsorption process for safety assessment of their geological disposal. In this study, adsorption of Np(V) to goethite, one of the widely distributed minerals was investigated as functions of pH and humic acid concentration. The surface charge density of goethite was determined and the zero charge point was 6.2 for synthesized and 6.4 for natural goethite. Since the point for humic acid was 4.5, adsorption sites for humic acid were reduced as the increase of negative charge density above pH6, resulting in a decrease in its adsorption rate. Np(V) adsorption to goethite was raised by the presence of humic acid in the range of 0-10ppm because the surface charge on the rock was shifted to negative by the adsorption of humic acid, resulting in easy adsorption of NpO{sub 2}{sup +}, which is stable in the condition below pH 9.5. On the other hand, humic acid adsorption was saturated at a concentration higher than 50 ppm, but its content in the solution would increase. Thus, it was thought that Np(V)-humic acid complex becomes more stable, resulting in the decrease in Np(V) adsorption rate. (M.N.)

  20. Preparation of Radiopharmaceuticals Labeled with Metal Radionuclides

    Energy Technology Data Exchange (ETDEWEB)

    Welch, M.J.

    2012-02-16

    The overall goal of this project was to develop methods for the production of metal-based radionuclides, to develop metal-based radiopharmaceuticals and in a limited number of cases, to translate these agents to the clinical situation. Initial work concentrated on the application of the radionuclides of Cu, Cu-60, Cu-61 and Cu-64, as well as application of Ga-68 radiopharmaceuticals. Initially Cu-64 was produced at the Missouri University Research Reactor and experiments carried out at Washington University. A limited number of studies were carried out utilizing Cu-62, a generator produced radionuclide produced by Mallinckrodt Inc. (now Covidien). In these studies, copper-62-labeled pyruvaldehyde Bis(N{sup 4}-methylthiosemicarbazonato)-copper(II) was studied as an agent for cerebral myocardial perfusion. A remote system for the production of this radiopharmaceutical was developed and a limited number of patient studies carried out with this agent. Various other copper radiopharmaceuticals were investigated, these included copper labeled blood imaging agents as well as Cu-64 labeled antibodies. Cu-64 labeled antibodies targeting colon cancer were translated to the human situation. Cu-64 was also used to label peptides (Cu-64 octriatide) and this is one of the first applications of a peptide radiolabeled with a positron emitting metal radionuclide. Investigations were then pursued on the preparation of the copper radionuclides on a small biomedical cyclotron. A system for the production of high specific activity Cu-64 was developed and initially the Cu-64 was utilized to study the hypoxic imaging agent Cu-64 ATSM. Utilizing the same target system, other positron emitting metal radionuclides were produced, these were Y-86 and Ga-66. Radiopharmaceuticals were labeled utilizing both of these radionuclides. Many studies were carried out in animal models on the uptake of Cu-ATSM in hypoxic tissue. The hypothesis is that Cu-ATSM retention in vivo is dependent upon the

  1. Cryogenic Adsorption of Nitrogen and Carbon Dioxide in Activated Carbon

    Science.gov (United States)

    Shen, Fuzhi; Liu, Huiming; Xu, Dong; Zhang, Hengcheng; Lu, Junfeng; Li, Laifeng

    2017-09-01

    Activated carbon have been used for a long time at low temperature for cryogenic applications. The knowledge of adsorption characteristics of activated carbon at cryogenic temperature is essential for some specific applications. However, such experimental data are very scare in the literature. In order to measure the adsorption characteristics of activated carbon under variable cryogenic temperatures, an adsorption measurement device was presented. The experiment system is based on the commercially available PCT-pro adsorption analyzer coupled to a two-stage Gifford McMahon refrigerator, which allows the sample to be cooled to 4.2K. Cryogenic environment can be maintained steadily without the cryogenic liquid through the cryocooler and temperature can be controlled precisely between 5K and 300K by the temperature controller. Adsorption measurements were performed in activated carbon for carbon dioxide and nitrogen and the adsorption isotherm were obtained.

  2. Radionuclide Mobility at the Nevada Test Site

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Q; Smith, D; Rose, T; Glascoe, L; Steefel, C; Zavarin, M

    2003-11-13

    Underground nuclear tests conducted at the Nevada Test Site (NTS) are characterized by abundant fission product and actinide source terms. Included are {sup 99}Tc and other soluble radionuclides ({sup 3}H, {sup 14}C, {sup 36}Cl, {sup 85}Kr, and {sup 129}I), which are presumably mobile in groundwater and potentially toxic to down-gradient receptors. NTS provides the Office of Civilian Radioactive Waste Management (OCRWM) with an analog of the release of these radionuclides from a nuclear waste repository in the absence of engineered barriers. The investigation described in this report synthesizes a substantial body of data collected on the identity and distribution of soluble radionuclides at field scales over distances of hundreds of meters, for durations up to 40 years, and under hydrogeologic conditions very similar to the proposed geological repository at Yucca Mountain. This body of data is complemented by laboratory transport studies and a synthesis of recent modeling investigations from the NTS, with an emphasis on the ongoing Yucca Mountain Program (YMP) efforts. Overall, understanding the controls of radionuclide mobility associated with these nuclear tests will provide insight into the repository's future performance as well as bounds and calibrations for the numerical predictions of long-term radionuclide releases and migration.

  3. Radionuclide Retention in Concrete Waste Forms

    Energy Technology Data Exchange (ETDEWEB)

    Mattigod, Shas V.; Bovaird, Chase C.; Wellman, Dawn M.; Wood, Marcus I.

    2010-09-30

    Assessing long-term performance of Category 3 waste cement grouts for radionuclide encasement requires knowledge of the radionuclide-cement interactions and mechanisms of retention (i.e., sorption or precipitation); the mechanism of contaminant release; the significance of contaminant release pathways; how waste form performance is affected by the full range of environmental conditions within the disposal facility; the process of waste form aging under conditions that are representative of processes occurring in response to changing environmental conditions within the disposal facility; the effect of waste form aging on chemical, physical, and radiological properties; and the associated impact on contaminant release. This knowledge will enable accurate prediction of radionuclide fate when the waste forms come in contact with groundwater. The information presented in the report provides data that 1) quantify radionuclide retention within concrete waste form materials similar to those used to encapsulate waste in the Low-Level Waste Burial Grounds (LLBG); 2) measure the effect of concrete waste form properties likely to influence radionuclide migration; and 3) quantify the stability of uranium-bearing solid phases of limited solubility in concrete.

  4. Radionuclide Retention in Concrete Wasteforms - FY13

    Energy Technology Data Exchange (ETDEWEB)

    Snyder, Michelle MV; Golovich, Elizabeth C.; Wellman, Dawn M.; Crum, Jarrod V.; Lapierre, Robert; Dage, Denomy C.; Parker, Kent E.; Cordova, Elsa A.

    2013-10-15

    Assessing long-term performance of Category 3 waste cement grouts for radionuclide encasement requires knowledge of the radionuclide-cement interactions and mechanisms of retention (i.e., sorption or precipitation); the mechanism of contaminant release; the significance of contaminant release pathways; how wasteform performance is affected by the full range of environmental conditions within the disposal facility; the process of wasteform aging under conditions that are representative of processes occurring in response to changing environmental conditions within the disposal facility; the effect of wasteform aging on chemical, physical, and radiological properties; and the associated impact on contaminant release. This knowledge will enable accurate prediction of radionuclide fate when the wasteforms come in contact with groundwater. Data collected throughout the course of this work will be used to quantify the efficacy of concrete wasteforms, similar to those used in the disposal of low-level waste and mixed low-level waste, for the immobilization of key radionuclides (i.e., uranium, technetium, and iodine). Data collected will also be used to quantify the physical and chemical properties of the concrete affecting radionuclide retention.

  5. Accumulation of radionuclides by lichen symbionts

    Energy Technology Data Exchange (ETDEWEB)

    Nifontova, M.G.; Kulikov, N.V. (AN SSSR, Sverdlovsk. Inst. Ehkologii Rastenij i Zhivotnykh)

    1983-01-01

    The aim of investigation is the quantitative estimation of ability and role of separate symbionts in the accumulation of radionuclides. As investigation volumes, durably cultivated green lichen alga Trebouxia erici and lichen fungi extracted from Cladonia rangiferina, Parmelia caperata and Acarospora fuscata are used. The accumulation of radioactive isotopes with fungi and seaweeds is estimated according to accumulation coefficients (AC) which are the ratio of radiation concentration in plants and agarized medium. Radionuclide content (/sup 90/Sr and /sup 137/Cs) is determined radiometrically. A special series of experiments is done to investigate radionuclide accumulation dependences with lichen seaweed and fungi on light conditions. It is shown that both symbionts of lichen-seaweed and fungus take part in the accumulation of radionuclide from outer medium (atmospheric fall-out and soil). However fungus component constituting the base of structural organization of thallus provides the greater part of radionuclides accumulated by the plant. Along with this the violation of viability of seaweed symbionts particularly in the case of light deficiency brings about the reduction of /sup 137/Cs sorption by seaweeds and tells on the total content of radiocesium in plant thallus.

  6. Radionuclides and heavy metals in Borovac, Southern Serbia.

    Science.gov (United States)

    Popovic, Dragana; Todorovic, Dragana; Frontasyeva, Marina; Ajtic, Jelena; Tasic, Mirjana; Rajsic, Slavica

    2008-09-01

    , honey, and water in Southern Serbia (Bujanovac) gave no evidence of the DU contamination of the environment 5 years after the military actions in 1999. Activities of radionuclides in soils were within the range of the values obtained in the other parts of the country and within the global average. The ratio of uranium isotopes confirmed the natural origin of uranium. In general, concentrations of heavy metals in the samples of soils, plant leaves, mosses, and lichen are found to be less or in the lower range of values found in other parts of the country, in spite of the differences in plant and moss species or soil characteristics. Possible sources of heavy metal contamination were identified as a power coal plant in the vicinity of the sampling sites and wood and waste burning processes. The collected data should provide a base for the health risk assessments on animals and humans in the near future. It should be emphasized that the sampling was carried out 5 years after the military action and that the number of samples was limited; therefore, the conclusions should be accepted only as observed tendencies and a detailed study should be recommended in the future.

  7. Interfacial adsorption of insulin - Conformational changes and reversibility of adsorption

    NARCIS (Netherlands)

    Mollmann, SH; Jorgensen, L; Bukrinsky, JT; Elofsson, U; Norde, W; Frokjaer, S

    2006-01-01

    The adsorption of human insulin to Teflon particles was studied with respect to conformational changes and the reversibility of adsorption was examined by total internal reflection fluorescence (TIRF). Adsorption isotherms for the adsorption of human insulin indicated high affinity adsorption, even

  8. Interfacial adsorption of insulin. Conformational changes and reversibility of adsorption

    NARCIS (Netherlands)

    Mollmann, S.H.; Bukrinsky, J.T.; Elofsson, U.; Norde, W.; Frokjaer, S.

    2006-01-01

    The adsorption of human insulin to Teflon particles was studied with respect to conformational changes and the reversibility of adsorption was examined by total internal reflection fluorescence (TIRF). Adsorption isotherms for the adsorption of human insulin indicated high affinity adsorption, even

  9. Workshop on development of radionuclide getters for the Yucca Mountain waste repository: proceedings.

    Energy Technology Data Exchange (ETDEWEB)

    Moore, Robert Charles; Lukens, Wayne W. (Lawrence Berkeley National Laboratory)

    2006-03-01

    The proposed Yucca Mountain repository, located in southern Nevada, is to be the first facility for permanent disposal of spent reactor fuel and high-level radioactive waste in the United States. Total Systems Performance Assessment (TSPA) analysis has indicated that among the major radionuclides contributing to dose are technetium, iodine, and neptunium, all of which are highly mobile in the environment. Containment of these radionuclides within the repository is a priority for the Yucca Mountain Project (YMP). These proceedings review current research and technology efforts for sequestration of the radionuclides with a focus on technetium, iodine, and neptunium. This workshop also covered issues concerning the Yucca Mountain environment and getter characteristics required for potential placement into the repository.

  10. Radionuclide contents in suspended sediments in relation to flood types in the lower Rhone River

    Energy Technology Data Exchange (ETDEWEB)

    Zebracki, Mathilde; Eyrolle-Boyer, Frederique; Antonelli, Christelle; Boullier, Vincent [IRSN / PRP-ENV, SESURE / LERCM, 13115 Saint-Paul-lez-Durance (France); De Vismes-Ott, Anne; Cagnat, Xavier [STEME / LMRE, 91400 Orsay (France)

    2013-07-01

    The aim of this work was to study the influence of watershed heterogeneity on the radionuclide contents of suspended particulate matter (SPM) in a large Mediterranean river. As the Rhone River catchment is characterized by a high climatic and geological heterogeneity, floods can be distinguished according to their geographic origins. Long-term time series of particles associated with radionuclides acquired in the framework of radiological surveillance provide a relevant dataset to investigate the variability of radionuclide contents. The SPM exported during Mediterranean floods differ from other floods as they display higher {sup 238}U and {sup 232}Th contents and the lowest activity ratio {sup 137}Cs/{sup (239+240)}Pu; these properties could be related to bedrock type and erosion process characteristics and/or to source term differentiation. (authors)

  11. Radionuclides incorporation in activated natural nanotubes; Incorporacao de radionuclideos em nanotubos naturais ativados

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Jose Parra

    2016-11-01

    Natural palygorskite nanotubes show suitable physical and chemical properties and characteristics to be use as potential nanosorbent and immobilization matrix for the concentration and solidification of radionuclides present in nuclear wastes. In the development process of materials with sorption properties for the incorporation and subsequent immobilization of radionuclides, the most important steps are related with the generation of active sites simultaneously to the increase of the specific surface area and suitable heat treatment to producing the structural folding. This study evaluated the determining parameters and conditions for the activation process of the natural palygorskite nanotubes aiming at the sorption of radionuclides in the nanotubes structure and subsequent evaluation of the parameters involve in the structural folding by heat treatments. The optimized results about the maximum sorption capacity of nickel in activated natural nanotubes show that these structures are apt and suitable for incorporation of radionuclides similar to nickel. By this study is verified that the optimization of the acid activation process is fundamental to improve the sorption capacities for specifics radionuclides by activated natural nanotubes. Acid activation condition optimized maintaining structural integrity was able to remove around 33.3 wt.% of magnesium cations, equivalent to 6.30·10{sup -4} g·mol{sup -1}, increasing in 42.8% the specific surface area and incorporating the same molar concentration of nickel present in the liquid radioactive waste at 80 min. (author)

  12. Cyclotron production of cesium radionuclides as analogues for francium-221 biodistribution

    Science.gov (United States)

    Finn, R.; McDevitt, M.; Sheh, Y.; Lom, C.; Qiao, J.; Cai, S.; Burnazi, E.; Nacca, A.; Pillarsetty, N.; Jaggi, J.; Scheinberg, D.

    2005-12-01

    In our clinical investigations focussing on improved therapeutic treatment of specific tumors we have concentrated on a targeted therapy approach utilizing designed radiolabeled monoclonal antibodies as the cytotoxic reagent. The physical characteristics of the alpha particle emitting radionuclide bismuth-213 including the short half-life of 45.6 min, has shown promise for the treatment of specific cancers such as leukemias and lymphomas or micrometastatic carcinomas. In an effort to increase the cytocidal effect of the HuM195, a humanized monoclonal antibody carrier to the CD33 antigen expressed on leukemia cells, our focus is directed toward an "internal" nano-generator composed of Ac-225 radionuclide, the parent of the bismuth-213. The actinium-225 radionuclide decays through several short-lived, alpha emitting daughters including francium-221, astatine-217 and bismuth-213. In order to study the biodistribution and the pharmacokinetics of the individual daughter nuclide, francium-221, the cyclotron production and separation of cesium radionuclides, specifically cesium-132, from a natural xenon gas target was undertaken. The choice of cesium as an analogue for francium was predicated upon both elements being in Group 1A alkali metals and cesium radionuclide possesses a sufficient half-life to allow biodistribution studies to be performed. The preliminary experimental results of this investigation are presented.

  13. Sequential extraction as a tool for mobility studies of radionuclides and metals in soils and sediments

    Energy Technology Data Exchange (ETDEWEB)

    Skipperud, Lindis; Salbu, Brit [Norwegian Univ. of Life Sciences, Aas (Norway). Dept. of Environmental Sciences (IMV)

    2015-06-01

    To assess the long term environmental impact of radioactive contamination of ecosystems, information on source terms including radionuclide speciation, mobility and biological uptake is of high importance. The speciation of radionuclides deposited or occurring naturally depends on source term and release scenario characteristics, transport and dispersion mechanisms and ecosystem properties. If mobile species are present, ecosystem transfer is relatively fast, whereas the ecosystem transfer is delayed if radionuclides are present as particles or incorporated in mineral lattices. This paper discusses cases showing important factors influencing the mobility of different radionuclides and metals. As examples can be given: - the difference between {sup 137}Cs and {sup 90}Sr from Chernobyl fallout and stable Cs and Sr in the soil showing that the fallout has not reached a steady state and therefore shows different mobility properties, thus the time since contamination is important. - the presence of organic matter affect the mobility of plutonium in soils and sediments even though the source term is the same. - physical properties (i.e. pH, OM, clay content, grain sice etc.) is important to interpret mobility data between similar sites. - the influence of industrial activity on radionuclides and metals shows that any man-made activity might change the mobility.

  14. Tl-208, Pb-212, Bi-212, Ra-226 and Ac-228 adsorption onto polyhydroxyethylmethacrylate-bentonite composite

    Energy Technology Data Exchange (ETDEWEB)

    Akkaya, Recep [Cumhuriyet University, Chemistry Department, 58140 Sivas (Turkey); Ulusoy, Ulvi, E-mail: ulusoy@cumhuriyet.edu.tr [Cumhuriyet University, Chemistry Department, 58140 Sivas (Turkey)

    2012-02-01

    The adsorption of naturally occurring radionuclides ({sup 208}Tl{sup +}, {sup 212}Pb{sup 2+}, {sup 226}Ra{sup 2+}, {sup 212}Bi{sup 3+} and {sup 228}Ac{sup 3+}) onto Polyhydroxyethylmethacrylate-bentonite (PHEMA-B) composite was investigated. Experimentally obtained isotherms were evaluated with reference to Langmuir, Freundlich and Dubinin-Radushkevich (DR) models. The adsorption isotherms were L type of Giles classification proving that PHEMA-B had a high affinity adsorbent for the studied radionuclides. The Langmuir adsorption capacities (X{sub L}) were in the order of {sup 226}Ra (2.8 MBq kg{sup -1})>{sup 212}Bi (0.4 MBq kg{sup -1})>{sup 212}Pb (0.3 MBq kg{sup -1})>{sup 228}Ac and {sup 208}Tl (0.2 MBq kg{sup -1}). The adsorption process was physical via complex formation after proton exchanger for which the adsorption energies obtained from DR model was evidence. The enthalpy and entropy changes were positive and the negative free enthalpy change was proof for the spontaneity of adsorption. The reusability tests for PHEMA-B for five uses demonstrated that the adsorbent could be reused after complete recovery of the loaded radionuclide ions by 1 M HCl. The chemical structure of the composite did not change after the reuses and storage foregoing.

  15. Tl-208, Pb-212, Bi-212, Ra-226 and Ac-228 adsorption onto polyhydroxyethylmethacrylate-bentonite composite

    Science.gov (United States)

    Akkaya, Recep; Ulusoy, Ulvi

    2012-02-01

    The adsorption of naturally occurring radionuclides ( 208Tl +, 212Pb 2+, 226Ra 2+, 212Bi 3+ and 228Ac 3+) onto Polyhydroxyethylmethacrylate-bentonite (PHEMA-B) composite was investigated. Experimentally obtained isotherms were evaluated with reference to Langmuir, Freundlich and Dubinin-Radushkevich (DR) models. The adsorption isotherms were L type of Giles classification proving that PHEMA-B had a high affinity adsorbent for the studied radionuclides. The Langmuir adsorption capacities ( XL) were in the order of 226Ra (2.8 MBq kg -1)> 212Bi (0.4 MBq kg -1)> 212Pb (0.3 MBq kg -1)> 228Ac and 208Tl (0.2 MBq kg -1). The adsorption process was physical via complex formation after proton exchanger for which the adsorption energies obtained from DR model was evidence. The enthalpy and entropy changes were positive and the negative free enthalpy change was proof for the spontaneity of adsorption. The reusability tests for PHEMA-B for five uses demonstrated that the adsorbent could be reused after complete recovery of the loaded radionuclide ions by 1 M HCl. The chemical structure of the composite did not change after the reuses and storage foregoing.

  16. Task 3: PNNL Visit by JAEA Researchers to Participate in TODAM Code Applications to Fukushima Rivers and to Evaluate the Feasibility of Adaptation of FLESCOT Code to Simulate Radionuclide Transport in the Pacific Ocean Coastal Water Around Fukushima

    Energy Technology Data Exchange (ETDEWEB)

    Onishi, Yasuo

    2013-03-29

    Four JAEA researchers visited PNNL for two weeks in February, 2013 to learn the PNNL-developed, unsteady, one-dimensional, river model, TODAM and the PNNL-developed, time-dependent, three dimensional, coastal water model, FLESCOT. These codes predict sediment and contaminant concentrations by accounting sediment-radionuclide interactions, e.g., adsorption/desorption and transport-deposition-resuspension of sediment-sorbed radionuclides. The objective of the river and coastal water modeling is to simulate • 134Cs and 137Cs migration in Fukushima rivers and the coastal water, and • their accumulation in the river and ocean bed along the Fukushima coast. Forecasting the future cesium behavior in the river and coastal water under various scenarios would enable JAEA to assess the effectiveness of various on-land remediation activities and if required, possible river and coastal water clean-up operations to reduce the contamination of the river and coastal water, agricultural products, fish and other aquatic biota. PNNL presented the following during the JAEA visit to PNNL: • TODAM and FLESCOT’s theories and mathematical formulations • TODAM and FLESCOT model structures • Past TODAM and FLESCOT applications • Demonstrating these two codes' capabilities by applying them to simple hypothetical river and coastal water cases. • Initial application of TODAM to the Ukedo River in Fukushima and JAEA researchers' participation in its modeling. PNNL also presented the relevant topics relevant to Fukushima environmental assessment and remediation, including • PNNL molecular modeling and EMSL computer facilities • Cesium adsorption/desorption characteristics • Experiences of connecting molecular science research results to macro model applications to the environment • EMSL tour • Hanford Site road tour. PNNL and JAEA also developed future course of actions for joint research projects on the Fukushima environmental and remediation assessments.

  17. Peptide receptor radionuclide therapy of neuroendocrine tumours.

    Science.gov (United States)

    Brabander, Tessa; Teunissen, Jaap J M; Van Eijck, Casper H J; Franssen, Gaston J H; Feelders, Richard A; de Herder, Wouter W; Kwekkeboom, Dik J

    2016-01-01

    In the past decades, the number of neuroendocrine tumours that are detected is increasing. A relative new and promising therapy for patients with metastasised or inoperable disease is peptide receptor radionuclide therapy (PRRT). This therapy involves an infusion of somatostatin analogues linked to radionuclides like Yttrium-90 or Lutetium-177. Objective response rates are reported in 15-35%. Response rates may vary between type of tumour and radionuclide. Besides the objective response rate, overall survival and progression free survival increase significantly. Also, the quality of life improves as well. Serious side-affects are rare. PRRT is usually well tolerated, also in patients with extensive metastasised disease. Recent studies combined PRRT with other types of therapies. Unfortunately no randomised trials comparing these strategies are available. In the future, more research is needed to evaluate the best therapy combinations or sequence of therapies.

  18. Therapeutic radionuclides: Making the right choice

    Energy Technology Data Exchange (ETDEWEB)

    Srivastava, S.C.

    1996-08-01

    Recently, there has been a resurgence of interest in nuclear medicine therapeutic procedures. Using unsealed sources for therapy is not a new concept; it has been around since the beginnings of nuclear medicine. Treatment of thyroid disorders with radioiodine is a classic example. The availability of radionuclides with suitable therapeutic properties for specific applications, as well as methods for their selective targeting to diseased tissue have, however, remained the main obstacles for therapy to assume a more widespread role in nuclear medicine. Nonetheless, a number of new techniques that have recently emerged, (e.g., tumor therapy with radiolabeled monoclonal antibodies, treatment of metastatic bone pain, etc.) appear to have provided a substantial impetus to research on production of new therapeutic radionuclides. Although there are a number of new therapeutic approaches requiring specific radionuclides, only selected broad areas will be used as examples in this article.

  19. 2014 LANL Radionuclide Air Emissions Report

    Energy Technology Data Exchange (ETDEWEB)

    Fuehne, David Patrick [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-07-21

    This report describes the emissions of airborne radionuclides from operations at Los Alamos National Laboratory (LANL) for calendar year 2014, and the resulting off-site dose from these emissions. This document fulfills the requirements established by the National Emissions Standards for Hazardous Air Pollutants in 40 CFR 61, Subpart H – Emissions of Radionuclides other than Radon from Department of Energy Facilities, commonly referred to as the Radionuclide NESHAP or Rad-NESHAP. Compliance with this regulation and preparation of this document is the responsibility of LANL’s RadNESHAP compliance program, which is part of the Environmental Protection Division. The information in this report is required under the Clean Air Act and is being submitted to the U.S. Environmental Protection Agency (EPA) Region 6.

  20. External accumulation of radionuclide in hepatic hydrothorax

    Energy Technology Data Exchange (ETDEWEB)

    Albin, R.J.; Johnston, G.S.

    1989-05-01

    Hepatic hydrothorax is a complication in approximately 5% of patients with cirrhosis. Ascites is almost always present and helps to suggest the correct diagnosis. However, when ascites is absent, radionuclide imaging has proven to be helpful in establishing that the pleural effusion originated from ascitic fluid. When pleural fluid is rapidly removed, such as by thoracostomy tube drainage, the radioisotope may accumulate outside the thorax and produce a negative scan of the chest. When the radionuclide scan is nondiagnostic and the pleural space is being rapidly drained, the pleural fluid collecting system should always be imaged before rejecting a diagnosis of hepatic hydrothorax.

  1. Radionuclide Therapies in Molecular Imaging and Precision Medicine.

    Science.gov (United States)

    Kendi, A Tuba; Moncayo, Valeria M; Nye, Jonathon A; Galt, James R; Halkar, Raghuveer; Schuster, David M

    2017-01-01

    This article reviews recent advances and applications of radionuclide therapy. Individualized precision medicine, new treatments, and the evolving role of radionuclide therapy are discussed. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. Migration of radionuclides in geologic media: Fundamental research needs

    Energy Technology Data Exchange (ETDEWEB)

    Reed, D.T. (Argonne National Lab., IL (USA)); Zachara, J.M.; Wildung, R.E. (Pacific Northwest Lab., Richland, WA (USA)); Wobber, F.J. (USDOE, Washington, DC (USA))

    1990-01-01

    An assessment of the fundamental research needs in understanding and predicting the migration of radionuclides in the subsurface is provided. Emphasis is on the following three technical areas: (1) aqueous speciation of radionuclides, (2) the interaction of radionuclides with substrates, and (3) intermediate-scale interaction studies. This research relates to important issues associated with environmental restoration and remediation of DOE sites contaminated with mixed radionuclide-organic wastes. 64 refs., 1 fig., 1 tab.

  3. Radiopharmaceuticals and other compounds labelled with short-lived radionuclides

    CERN Document Server

    Welch, Michael J

    2013-01-01

    Radiopharmaceuticals and Other Compounds Labelled with Short-Lived Radionuclides covers through both review and contributed articles the potential applications and developments in labeling with short-lived radionuclides whose use is restricted to institutions with accelerators. The book discusses the current and potential use of generator-produced radionuclides as well as other short-lived radionuclides, and the problems of quality control of such labeled compounds. The book is useful to nuclear medicine physicians.

  4. Activity measurement of /sup 33/P and /sup 32/P radionuclide mixture

    Energy Technology Data Exchange (ETDEWEB)

    Hanker, I.; Kansky, Z.

    1984-04-01

    The possibilities are briefly summed up of measuring mixtures of /sup 33/P and /sup 32/P with special regard to the method of simultaneous determination of both radionuclides in a liquid scintillator. This method was experimentally tested for special detection sensitivity and intended special applications in plant physiology and biochemistry using a dioxane scintillator (SLD-31, Spolana Neratovice, CSSR) and a Packard Tri-Carb 300 C, USA. The method gave erroneous results. The main cause of the errors in measurements of the /sup 33/P and /sup 32/P mixture in the SLD-31 was the adsorption of radionuclides on the inner wall of glass tubes. This phenomenon is not accompanied by changes in the quenching index. However, the effectiveness of measurement dropped and the relative contribution of the spectra of the two radionuclides changed with the time following sample preparation. The said effects were removed by adding 0.4% silicon dioxide (Cab-O-Sil M5, Serva) to the liquid scintillator.

  5. In-Package Sorption Controls Over Radionuclide Export from the Proposed Repository at Yucca Mtn

    Science.gov (United States)

    brady, p v

    2001-12-01

    Performance assessment calculations done to assess the long-term effectiveness of the proposed high level radioactive waste repository at Yucca Mtn. Nevada tend to ignore sorption of radionuclides onto degradation products (primarily oxides of iron and, to a lesser extent, copper) that are expected to accumulate inside of breached waste packages. While conservative with respect to human health impacts, ignoring sorption onto iron hydroxides neglects one of the more effective obstacles to radionuclide transport in natural environments. A series of one-dimensional transport calculations done using the reaction-path transport codes PHREEQC and Langmuir, measured adsorption and desorption isotherms for Pu, Np, and Tc, and a series of model in-package flow paths allow assessment of reversible and irreversible sorption controls over radionuclide sorption fronts that are predicted to form inside and in the immediate vicinity of breached WP's. Natural analogue evidences (e.g. bomb pulse Pu profiles and chemical potential gradients at the natural reactor at Oklo) provide partial validation

  6. Surface complexation modeling of the effects of phosphate on uranium(VI) adsorption

    Energy Technology Data Exchange (ETDEWEB)

    Romero-Gonzalez, M.R.; Cheng, T.; Barnett, M.O. [Auburn Univ., AL (United States). Dept. of Civil Engeneering; Roden, E.E. [Wisconsin Univ., Madison, WI (United States). Dept. of Geology and Geophysics

    2007-07-01

    Previous published data for the adsorption of U(VI) and/or phosphate onto amorphous Fe(III) oxides (hydrous ferric oxide, HFO) and crystalline Fe(III) oxides (goethite) was examined. These data were then used to test the ability of a commonly-used surface complexation model (SCM) to describe the adsorption of U(VI) and phosphate onto pure amorphous and crystalline Fe(III) oxides and synthetic goethite-coated sand, a surrogate for a natural Fe(III)-coated material, using the component additivity (CA) approach. Our modeling results show that this model was able to describe U(VI) adsorption onto both amorphous and crystalline Fe(III) oxides and also goethite-coated sand quite well in the absence of phosphate. However, because phosphate adsorption exhibits a stronger dependence on Fe(III) oxide type than U(VI) adsorption, we could not use this model to consistently describe phosphate adsorption onto both amorphous and crystalline Fe(III) oxides and goethite-coated sand. However, the effects of phosphate on U(VI) adsorption could be incorporated into the model to describe U(VI) adsorption to both amorphous and crystalline Fe(III) oxides and goethite-coated sand, at least for an initial approximation. These results illustrate both the potential and limitations of using surface complexation models developed from pure systems to describe metal/radionuclide adsorption under more complex conditions. (orig.)

  7. 21 CFR 892.5650 - Manual radionuclide applicator system.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Manual radionuclide applicator system. 892.5650... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Therapeutic Devices § 892.5650 Manual radionuclide applicator system. (a) Identification. A manual radionuclide applicator system is a manually operated...

  8. Plant uptake of radionuclides and rhizosphere factors

    Energy Technology Data Exchange (ETDEWEB)

    Arie, Tsutomu; Gouthu, S.; Ambe, Shizuko; Yamaguchi, Isamu [Institute of Physical and Chemical Research, Wako, Saitama (Japan); Hirata, Hiroaki

    1999-03-01

    Influence of soil factors such as nuclide availability, pH, organic carbon, cation exchange capacity (CEC), exchangeable cations (Ca{sup 2+}, Mg{sup 2+}, and K{sup +}), phosphate absorption coefficient (PAC), physical composition of soil (coarse sand, fine sand, silt, and clay), soil texture, and rhizosphere microbes on uptake of radionuclides by plants are studied. (author)

  9. Radionuclide tumor therapy with ultrasound contrast microbubbles

    NARCIS (Netherlands)

    Wamel, van Annemieke; Bouakaz, Ayache; Bernard, Bert; Cate, ten Folkert; Jong, de Nico

    2004-01-01

    Radionuclides have shown to be effective in tumour therapy. However, the side effects determine the maximum deliverable dose. Recently, it has been demonstrated that cells can be permeabilised through sonoporation using ultrasound and contrast microbubbles. The use of sonoporation in treatment of tu

  10. Chapter 7: Primary standardization in radionuclide metrology

    Energy Technology Data Exchange (ETDEWEB)

    Delgado, Jose Ubiratan

    2014-07-01

    The chapter 7 presents: Primary methods for radionuclide standardization; 4πβ-γ Coincidence counting method; Anticoincidence; Counting π Method; Defined Solid Angle Counting Method; Liquid scintillator counting method (CIEMAT/NIST); Sum-peak Method and LNMRI Absolute Standardization.

  11. Radionuclide Geomicrobiology of the Deep Biosphere

    DEFF Research Database (Denmark)

    Anderson, Craig; Johnsson, Anna; Moll, Henry

    2011-01-01

    species (i.e., Shewanella putrefaciens and Desulfovibrio aespoeensis) with Cm, Pm, and Pu were investigated in vitro and the results were found to agree with literature data. Siderophores are capable of binding actinides strongly and need to be considered in terms of radionuclide mobility...

  12. RADIONUCLIDE TRANSPORT MODELS UNDER AMBIENT CONDITIONS

    Energy Technology Data Exchange (ETDEWEB)

    S. Magnuson

    2004-11-01

    The purpose of this model report is to document the unsaturated zone (UZ) radionuclide transport model, which evaluates, by means of three-dimensional numerical models, the transport of radioactive solutes and colloids in the UZ, under ambient conditions, from the repository horizon to the water table at Yucca Mountain, Nevada.

  13. Radionuclide imaging of bone marrow disorders

    NARCIS (Netherlands)

    Agool, Ali; Glaudemans, Andor W. J. M.; Boersma, Hendrikus H.; Dierckx, Rudi A. J. O.; Vellenga, Edo; Slart, Riemer H. J. A.

    2011-01-01

    Noninvasive imaging techniques have been used in the past for visualization the functional activity of the bone marrow compartment. Imaging with radiolabelled compounds may allow different bone marrow disorders to be distinguished. These imaging techniques, almost all of which use radionuclide-label

  14. Structure sensitivity in adsorption

    DEFF Research Database (Denmark)

    Hammer, Bjørk; Nielsen, Ole Holm; Nørskov, Jens Kehlet

    1997-01-01

    The structure sensitivity of CO adsorption on different flat, stepped, kinked and reconstructed Pt surfaces is studied using large-scale density-functional calculations. We find an extremely strong structure sensitivity in the adsorption energy with variations up to 1 eV (or 100%) from one...

  15. A Simple Adsorption Experiment

    Science.gov (United States)

    Guirado, Gonzalo; Ayllon, Jose A.

    2011-01-01

    The study of adsorption phenomenon is one of the most relevant and traditional physical chemistry experiments performed by chemistry undergraduate students in laboratory courses. In this article, we describe an easy, inexpensive, and straightforward way to experimentally determine adsorption isotherms using pieces of filter paper as the adsorbent…

  16. Scientific Analysis Cover Sheet for Radionuclide Screening

    Energy Technology Data Exchange (ETDEWEB)

    G. Ragan

    2002-08-09

    The waste forms under consideration for disposal in the proposed repository at Yucca Mountain contain scores of radionuclides (Attachments V and VI). It would be impractical and highly inefficient to model all of these radionuclides in a total system performance assessment (TSPA). Thus, the purpose of this radionuclide screening analysis is to remove from further consideration (screen out) radionuclides that are unlikely to significantly contribute to radiation dose to the public from the proposed nuclear waste repository at Yucca Mountain. The remaining nuclides (those screened in) are recommended for consideration in TSPA modeling for license application. This analysis also covers radionuclides that are not screened in based on dose, but need to be included in TSPA modeling for other reasons. For example, U.S. Environmental Protection Agency (EPA) and U.S. Nuclear Regulatory Commission (NRC) regulations require consideration of the combined activity of Ra-226 and Ra-228 in groundwater (40 CFR 197.30, 10 CFR 63.331). Also, Cm-245, Pu-241, and U-235 decay indirectly to potentially important radionuclides, and are not identified by the screening analysis as important. The radionuclide screening analysis separately considers two different postclosure time periods: the 10,000-y regulatory period for the proposed repository at Yucca Mountain and the period after 10,000 y up to 1 million y after emplacement. The incremental effect of extending the screening for the regulatory period to 20,000 y is also addressed. Four release scenarios are considered: (1) the nominal scenario, which entails long-term degradation of disposal containers and waste forms, (2) a human-intrusion scenario, (3) an intrusive igneous event, and (4) an eruptive igneous event. Because the first three scenarios require groundwater transport, they are called groundwater scenarios below. The screening analysis considers the following waste forms: spent boiling water reactor (BWR) fuel, spent

  17. Phosphorus solubilizing bacteria growth and effects on soil phosphorus adsorption-desorption characteristics in reclaimed soils%磷细菌在复垦土壤上生长规律及对磷解析特性的影响

    Institute of Scientific and Technical Information of China (English)

    李娜; 乔志伟; 洪坚平; 谢英荷; 张铁全

    2015-01-01

    ecological environment in subsidence areas. Phosphorus (P) solubilizing bacteria in soil, an important role in P cycling, can convert insoluble phosphate into available P. Application of P solubilizing bacteria is an effective bio-measure in improvement of reclaimed soil. However, the effects of P solubilizing bacteria on P adsorption-desorption in reclaimed soil have been less concerned. In this study, reclamation soil samples were collected in mining-driven subsidence areas and laboratory incubation experiments conducted via application of P solubilizing bacteria and other different fertilizers (glucose, G; urine, U; organic fertilizer, M) on reclaimed soils. The soil available P, organic P contents and P adsorption-desorption characteristics were investigated after different times of incubation. The objectives of the study were to determine the P solubilizing bacteria effects on soil P nutrient and provide reference for rapid fertility of reclaimed soils. Seven treatments were conducted — control (no bacteria and fertilizers, CK); P solubilizing bacteria only (B); organic fertilizer only (M); P solubilizing bacteria and glucose (BG); P solubilizing bacteria and urine (BU); P solubilizing bacteria, glucose and urine (BGU); and P solubilizing bacteria, glucose, urine and organic fertilizer (BGUM). The amount of P solubilizing bacteria in one pot with 500 g soil was 5 mL P solubilizing bacteria fermented liquid (with P·solubilizing bacteria 1.2×108 CFU·mL-1). The results showed that the amount of P solubilizing bacteria in soil initially increased and then decreased during the incubation period. Under BGUM treatment, the amount of P solubilizing bacteria decreased from 1.0×106 CFU·g-1 at the start of the experiment to 3.3×104 CFU·g-1 after 60 days of cultivation, which was 300, 367, 1 650 and 3 300 times of those of BGU, BG, BU and B treatments, respectively. Soil available P contents of M, B and BGUM treatments were 172.27 mg·kg-1, 3.00 mg·kg-1 and188.9 mg·kg-1

  18. RADIONUCLIDES DISTRIBUTION NEAR FORMER URANIUM MINING

    Directory of Open Access Journals (Sweden)

    D. A. Zaredinov

    2016-01-01

    Full Text Available The paper shows, that radionuclides from the stony rocks of uranium mines can be leached by atmospheric precipitations. In acid conditions, a degree of leaching is greater.Goal. The aim of this investigation was to study the distribution of radionuclides in uranium minings and their impact on the environmental contamination.Materials and methods. The study was carried out in two stages. In the first stage, a blade of rock was mixed with distilled water in proportions of 0,3 kg of gravel and 1 liter of water. After thirty days of soaking, water was sent to the gamma-spectrometric analysis to Canberra’s spectrometer (USA with a high-purity germanium detector. In the second stage, we carried out the similar experiment with water, wich was acidified to pH = 3. Contamination levels of areas near the in-situ leaching mine were determined. Intervention levels were used to estimate risk and possible water consumption by the population. Estimations were carried out taking into account the combined presence of several radionuclides in the water.Results. The results of these studies have shown that the distribution of radionuclides from the source of the contamination is about 360 meters during the 30 y period. The stream, along which samples of soil were collected and studied, was formed by the miner waters that flow along small ruts towards a village, thereby increasing the likelihood of water use by the public.Conclusions. The uranium mines are the source of radioactive contamination. Radionuclides are distributed due to the erosion of rocks and leached out of the stony rock by precipitations. The extent of leaching is significantly increased in an acidic environment, which takes place near the in-situ leaching mines.

  19. 2006 LANL Radionuclide Air Emissions Report

    Energy Technology Data Exchange (ETDEWEB)

    David P. Fuehne

    2007-06-30

    This report describes the impacts from emissions of radionuclides at Los Alamos National Laboratory (LANL) for calendar year 2006. This report fulfills the requirements established by the Radionuclide National Emissions Standards for Hazardous Air Pollutants (Rad-NESHAP). This report is prepared by LANL's Rad-NESHAP compliance team, part of the Environmental Protection Division. The information in this report is required under the Clean Air Act and is being reported to the U.S. Environmental Protection Agency (EPA). The highest effective dose equivalent (EDE) to an off-site member of the public was calculated using procedures specified by the EPA and described in this report. LANL's EDE was 0.47 mrem for 2006. The annual limit established by the EPA is 10 mrem per year. During calendar year 2006, LANL continuously monitored radionuclide emissions at 28 release points, or stacks. The Laboratory estimates emissions from an additional 58 release points using radionuclide usage source terms. Also, LANL uses a network of air samplers around the Laboratory perimeter to monitor ambient airborne levels of radionuclides. To provide data for dispersion modeling and dose assessment, LANL maintains and operates meteorological monitoring systems. From these measurement systems, a comprehensive evaluation is conducted to calculate the EDE for the Laboratory. The EDE is evaluated as any member of the public at any off-site location where there is a residence, school, business, or office. In 2006, this location was the Los Alamos Airport Terminal. The majority of this dose is due to ambient air sampling of plutonium emitted from 2006 clean-up activities at an environmental restoration site (73-002-99; ash pile). Doses reported to the EPA for the past 10 years are shown in Table E1.

  20. Insights into Local Sediment Radionuclide Absorption and Retention in the island of Puerto Rico

    Science.gov (United States)

    Ithier-Guzman, W.; Pyrtle, A. J.

    2005-12-01

    Anthropogenic radionuclides have been introduced to Puerto Rico, a United States (US) Commonwealth, via two major sources: global atmospheric fallout and local US government-sponsored tropical ecosystem experiments, prototype nuclear reactor testing and military artillery exercises. In October 2003 a preliminary investigation was initiated to examine the distribution and behavior of anthropogenic radionuclides in the Caribbean National Forest, Vieques and Rincon. During this investigation, sediment, vegetation and water samples were collected and analyzed. Analytical results of sediment samples indicate the presence of anthropogenic radionuclides at all three sample locations. Surface and downcore 137Cs distributions, as well as particle size characteristics of sediments collected from Vieques and Rincon are presented below. Results indicate that surface 137Cs activities at the Vieques sampling sites range from below detection limits to 0.01 Bq/g. Particle concentrations vary at each location. The average concentration of clay size particles are slightly higher at Kiani Lagoon (6 % clay) than at Mosquito Bay (2 % clay). It is anticipated that outcomes from this on-going investigation will include an increased understanding of radionuclide concentrations, distributions and behaviors, with respect to local aquatic geochemistry, dominant transport processes and ecological characteristics.

  1. Microscopic theory of hysteretic hydrogen adsorption in nanoporous materials.

    Science.gov (United States)

    Kang, Joongoo; Wei, Su-Huai; Kim, Yong-Hyun

    2010-02-10

    Understanding gas adsorption confined in nanoscale pores is a fundamental issue with broad applications in catalysis and gas storage. Recently, hysteretic H(2) adsorption was observed in several nanoporous metal-organic frameworks (MOFs). Here, using first-principles calculations and simulated adsorption/desorption isotherms, we present a microscopic theory of the enhanced adsorption hysteresis of H(2) molecules using the MOF Co(1,4-benzenedipyrazolate) [Co(BDP)] as a model system. Using activated H(2) diffusion along the small-pore channels as a dominant equilibration process, we demonstrate that the system shows hysteretic H(2) adsorption under changes of external pressure. For a small increase of temperature, the pressure width of the hysteresis, as well as the adsorption/desorption pressure, dramatically increases. The sensitivity of gas adsorption to temperature changes is explained by the simple thermodynamics of the gas reservoir. Detailed analysis of transient adsorption dynamics reveals that the hysteretic H(2) adsorption is an intrinsic adsorption characteristic in the diffusion-controlled small-pore systems.

  2. [Treatment of organic waste gas by adsorption rotor].

    Science.gov (United States)

    Zhu, Run-Ye; Zheng, Liang-Wei; Mao, Yu-Bo; Wang, Jia-De

    2013-12-01

    The adsorption rotor is applicable to treating organic waste gases with low concentration and high air volume. The performance of adsorption rotor for purifying organic waste gases was investigated in this paper. Toluene was selected as the simulative gaseous pollutant and the adsorption rotor was packed with honeycomb modified 13X molecular sieves (M-13X). Experimental results of the fixed adsorption and the rotor adsorption were analyzed and compared. The results indicated that some information on the fixed adsorption was useful for the rotor adsorption. Integrating the characteristics of the adsorbents, waste gases and the structures of the rotor adsorption, the formulas on optimal rotor speed and cycle removal efficiency of the adsorption rotor were deduced, based on the mass and heat balances of the adsorbing process. The numerical results were in good agreement with the experimental data, which meant that the formulas on optimal rotor speed and cycle removal efficiency could be effectively applied in design and operation of the adsorption rotor.

  3. Experimental study on gas permeability by adsorption under 3D-stress

    Institute of Scientific and Technical Information of China (English)

    LONG Qing-ming; WEN Guang-cai; ZOU Yin-hui; ZHAO Xu-sheng

    2009-01-01

    Using self-developed gas-seepage experimental installation, under the same effective stress conditions, coal permeability experiments on different adsorption charac-teristics of gases, different temperatures and different gas adsorption contents were per-formed, and the influence law of adsorption on coal permeability was studied. At the same time, experimental analogy showed clearly that gas drawing plucks the permeability varia-tion law. The results show that adsorption has a major impact on coal permeability. The greater the adsorption, the more the gas adsorption capacity and the coal permeability becomes smaller. Permeability becomes smaller along with confining of pressure and temperature, and this is in accord with local practice results.

  4. Research progress of novel adsorption processes in water purification:A review

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    As an effective, efficient, and economic approach for water purification, adsorbents and adsorption processes have been widely studied and applied in different aspects for a long time. In the recent years, a lot of novel adsorption processes have been developed for enhancing the efficiency of removing the organic and inorganic contaminants from water. This article reviews some new adsorbents and advanced adsorption methods that specialize in their compositions, structures, functions, and characteristics used in water treatment. The review emphasizes adsorption/catalytic oxidation process, adsorption/catalytic reduction process, adsorption coupled with redox process, biomimetic sorbent and its sorption behaviors of POPs, and modified adsorbents and their water purification efficiency.

  5. Radioactivity and the environment: technical approaches to understand the role of arbuscular mycorrhizal plants in radionuclide bioaccumulation

    Directory of Open Access Journals (Sweden)

    Helena S. Davies

    2015-07-01

    Full Text Available Phytoaccumulation of radionuclides is of significant interest with regards to monitoring radionuclide build-up in food chains, developing methods for environmental bioremediation and for ecological management. There are many gaps in our understanding of the characteristics and mechanisms of plant radionuclide accumulation, including the importance of symbiotically-associated arbuscular mycorrhizal (AM fungi. We first briefly review the evidence that demonstrates the ability of AM fungi to enhance the translocation of 238U into plant root tissues, and how fungal association may prevent further mobilization into shoot tissues. We then focus on approaches that should further advance our knowledge of AM fungi-plant radionuclide accumulation. Current research has mostly used artificial cultivation methods and we consider how more ecologically-relevant analysis might be performed. The use of synchrotron-based X-ray fluorescence imaging and absorption spectroscopy techniques to understand the mechanisms of radionuclide transfer from soil to plant via AM fungi is evaluated. Without such further knowledge, the behavior and mobilization of radionuclides cannot be accurately modelled and the potential risks cannot be accurately predicted.

  6. Development of a portable equipment for identification of radionuclides; Desenvolvimento de um equipamento portatil para identificacao de radionuclideos

    Energy Technology Data Exchange (ETDEWEB)

    Farias, Marcos Santana; Carvalho, Paulo Victor R. de, E-mail: msantana@ien.gov.br [Instituto de Engenharia Nuclear (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil). Div. de Engenharia Nuclear; Nedjah, Nadia, E-mail: nadia@eng.uerj.br [Universidade do Estado do Rio de Janeiro (UERJ), Rio de Janeiro, RJ (Brazil). Dept. de Engenharia Eletronica e Telecomunicacoes; Mourelle, Luiza de Macedo, E-mail: ldmm@eng.uerj.br [Universidade do Estado do Rio de Janeiro (UERJ), Rio de Janeiro, RJ (Brazil). Dept. de Engenharia de Sistemas e Computacao

    2014-07-01

    The rapid and automatic identification of radionuclides present in a radioactive sample detected in the field, is information that helps in decision making. In areas of high traffic of people and materials, such as ports and airports as well as at major events, radiation monitoring, together with the identification of the radionuclide, it is advisable within protective standards to the public. The correct identification of radionuclides depends on the ability to determine whether specific peaks energy sources are present in the spectrum of gamma radiation sources. Radionuclides can be identified by these energy characteristics in the sense that the energy value associated with these peaks in the spectrum corresponds to the radiation sources present in the sample. There are many methods that can be used for automatic identification of radionuclides. Most of them are based on software algorithms for the detection of peaks in the energy spectrum. Processing time of these tasks can be very long for applications requiring quick responses, as in equipment portable. A dedicated digital hardware offers better performance for tasks with high processing demand like this. This work shows the development of a handle Portable radionuclides based on a digital hardware solution using a FPGA (Field Programmable Gate Array) for implementing a clustering algorithm for the detection of energy peaks. (author)

  7. Adsorption of CO2 and H2O on supported amine sorbents

    NARCIS (Netherlands)

    Veneman, R.; Zhao, W.; Li, Z.; Cai, N.; Brilman, D.W.F.

    2014-01-01

    In this work we have evaluated the H2O and CO2 adsorption characteristics of Lewatit VP OC 1065 in view of the potential application of solid sorbents in post combustion CO2 capture. Here we present single component adsorption isotherms for H2O and CO2 as well as co-adsorption experiments. It was co

  8. Gas-phase formaldehyde adsorption isotherm studies on activated carbon: correlations of adsorption capacity to surface functional group density.

    Science.gov (United States)

    Carter, Ellison M; Katz, Lynn E; Speitel, Gerald E; Ramirez, David

    2011-08-01

    Formaldehyde (HCHO) adsorption isotherms were developed for the first time on three activated carbons representing one activated carbon fiber (ACF) cloth, one all-purpose granular activated carbon (GAC), and one GAC commercially promoted for gas-phase HCHO removal. The three activated carbons were evaluated for HCHO removal in the low-ppm(v) range and for water vapor adsorption from relative pressures of 0.1-0.9 at 26 °C where, according to the IUPAC isotherm classification system, the adsorption isotherms observed exhibited Type V behavior. A Type V adsorption isotherm model recently proposed by Qi and LeVan (Q-L) was selected to model the observed adsorption behavior because it reduces to a finite, nonzero limit at low partial pressures and it describes the entire range of adsorption considered in this study. The Q-L model was applied to a polar organic adsorbate to fit HCHO adsorption isotherms for the three activated carbons. The physical and chemical characteristics of the activated carbon surfaces were characterized using nitrogen adsorption isotherms, X-ray photoelectron spectroscopy (XPS), and Boehm titrations. At low concentrations, HCHO adsorption capacity was most strongly related to the density of basic surface functional groups (SFGs), while water vapor adsorption was most strongly influenced by the density of acidic SFGs.

  9. Uptake by plants of radionuclides from FUSRAP waste materials

    Energy Technology Data Exchange (ETDEWEB)

    Knight, M.J.

    1983-04-01

    Radionuclides from FUSRAP wastes potentially may be taken up by plants during remedial action activities and permanent near-surface burial of contaminated materials. In order to better understand the propensity of radionuclides to accumulate in plant tissue, soil and plant factors influencing the uptake and accumulation of radionuclides by plants are reviewed. In addition, data describing the uptake of the principal radionuclides present in FUSRAP wastes (uranium-238, thorium-230, radium-226, lead-210, and polonium-210) are summarized. All five radionuclides can accumulate in plant root tissue to some extent, and there is potential for the translocation and accumulation of these radionuclides in plant shoot tissue. Of these five radionuclides, radium-226 appears to have the greatest potential for translocation and accumulation in plant shoot tissue. 28 references, 1 figure, 3 tables.

  10. Application of activated carbon derived from scrap tires for adsorption of Rhodamine B.

    Science.gov (United States)

    Li, Li; Liu, Shuangxi; Zhu, Tan

    2010-01-01

    Activated carbon derived from solid hazardous waste scrap tires was evaluated as a potential adsorbent for cationic dye removal. The adsorption process with respect to operating parameters was investigated to evaluate the adsorption characteristics of the activated pyrolytic tire char (APTC) for Rhodamine B (RhB). Systematic research including equilibrium, kinetics and thermodynamic studies was performed. The results showed that APTC was a potential adsorbent for RhB with a higher adsorption capacity than most adsorbents. Solution pH and temperature exert significant influence while ionic strength showed little effect on the adsorption process. The adsorption equilibrium data obey Langmuir isotherm and the kinetic data were well described by the pseudo second-order kinetic model. The adsorption process followed intra-particle diffusion model with more than one process affecting the adsorption process. Thermodynamic study confirmed that the adsorption was a physisorption process with spontaneous, endothermic and random characteristics.

  11. Competitive Protein Adsorption - Multilayer Adsorption and Surface Induced Protein Aggregation

    DEFF Research Database (Denmark)

    Holmberg, Maria; Hou, Xiaolin

    2009-01-01

    In this study, competitive adsorption of albumin and IgG (immunoglobulin G) from human serum solutions and protein mixtures onto polymer surfaces is studied by means of radioactive labeling. By using two different radiolabels (125I and 131I), albumin and IgG adsorption to polymer surfaces...... is monitored simultaneously and the influence from the presence of other human serum proteins on albumin and IgG adsorption, as well as their mutual influence during adsorption processes, is investigated. Exploring protein adsorption by combining analysis of competitive adsorption from complex solutions...... of high concentration with investigation of single protein adsorption and interdependent adsorption between two specific proteins enables us to map protein adsorption sequences during competitive protein adsorption. Our study shows that proteins can adsorb in a multilayer fashion onto the polymer surfaces...

  12. Removal and Recovery of Some From Simulated Nuclear Waste Radionuclides Using Amberlite XAD-16-Pyridylazo Resorcinol (AXAD-PR) Composite

    Science.gov (United States)

    Akçağlar, Sevil

    2016-04-01

    In this study, Amberlite XAD-16-Pyridylazo resorcinol composite (AXAD-PR) were developed under laboratory conditions to detect the removals and recoveries of U(IV) and Am(III) from simulated nuclear wastes by adsorption and desorption processes. The effects of contacting time (5, 15, 25 and 200 min), of AXAD-PR concentrations (5, 25, 50 and 100 mg/l), of temperatures (15, 30 and 45°C), increasing U(IV) and Am(III) concentrations (1, 5, 10, 15, 20, 30 and 40) and pH levels (acidic, basic and neutral conditions) on the removals and recoveries of U(IV) and Am(III) radionuclides were investigated. The data obtained showed that the maximum adsorption yields of U(IV) and Am(III) were found to be 96% and 95%, respectively, after 25 min using 25 mg/l AXAD-PR at 30°C at an acidic pH of 5. The adsorption kinetic of radionuclides to AXAD-PR isotherm was in accordance with Langmuir. The AXAD-PR can be reused and can be used again. The regeneration of the composite is possible and can be attained a desorption efficiency of 99% using 0.4 M HNO3 acid solution from 25 mg/l prepared AXAD-PR.

  13. Identifying large chondrites using cosmogenic radionuclides

    Energy Technology Data Exchange (ETDEWEB)

    Welten, K.C. [Space Sciences Laboratory, University of California, Berkeley, CA 94720-7450 (United States); Caffee, M.W., E-mail: mcaffee@purdue.ed [PRIME Laboratory, Purdue University, West Lafayette, IN 47907 (United States); Hillegonds, D.J. [Center for Accelerator Mass Spectrometry, Lawrence Livermore National Laboratory, Livermore, CA 94550 (United States); Masarik, J. [Department of Nuclear Physics, Comenius University, Bratislava (Slovakia); Nishiizumi, K. [Space Sciences Laboratory, University of California, Berkeley, CA 94720-7450 (United States)

    2010-04-15

    We measured the concentrations of the cosmogenic radionuclides {sup 10}Be, {sup 26}Al, {sup 36}Cl and {sup 41}Ca in the metal and stone fractions of three large chondrite showers to determine their pre-atmospheric size. Large chondrites are characterized by substantial contributions of neutron-capture {sup 41}Ca in the stone fraction (up to approx2 dpm/gCa), low radionuclide concentrations in the metal fraction and high {sup 10}Be(stone)/{sup 10}Be(metal) ratios. Based on the measured concentrations in comparison with calculated cosmogenic nuclide depth profiles, using a semi-empirical and a purely physical model, we conclude that these objects had pre-atmospheric radii ranging from approx80 cm to >3 m. We conclude that the semi-empirical model is more reliable for spallogenic production rates in large objects, while the purely physical model is more reliable for neutron-capture products.

  14. Tracing Noble Gas Radionuclides in the Environment

    CERN Document Server

    Collon, P; Lu, Z T

    2004-01-01

    Trace analysis of radionuclides is an essential and versatile tool in modern science and technology. Due to their ideal geophysical and geochemical properties, long-lived noble gas radionuclides, in particular, 39Ar (t1/2 = 269 yr), 81Kr (t1/2 = 2.3x10^5 yr) and 85Kr (t1/2 = 10.8 yr), have long been recognized to have a wide range of important applications in Earth sciences. In recent years, significant progress has been made in the development of practical analytical methods, and has led to applications of these isotopes in the hydrosphere (tracing the flow of groundwater and ocean water). In this article, we introduce the applications of these isotopes and review three leading analytical methods: Low-Level Counting (LLC), Accelerator Mass Spectrometry (AMS) and Atom Trap Trace Analysis (ATTA).

  15. Radionuclide synovectomy – essentials for rheumatologists

    Directory of Open Access Journals (Sweden)

    Marek M. Chojnowski

    2016-07-01

    Full Text Available Radionuclide synovectomy is a minimally invasive method of treating persistent joint inflammation. It involves intra-articular injection of radioactive colloids which induce necrosis and fibrosis of hypertrophic synovial membrane. The most common indication for radiosynovectomy is rheumatoid arthritis, although patients with seronegative spondyloarthropathies, unclassified arthritis, haemophilic arthropathy and other less common arthropathies can also benefit from this method. Radiosynovectomy is safe, well tolerated and efficacious. About 70–80% of patients respond well to the therapy. However, the therapeutic effects are considerably worse in patients with co-existent osteoarthritis and advanced joint degeneration. Despite its advantages, radionuclide synovectomy is not performed as often as it could be, so greater knowledge and understanding of this method are needed. The authors present the most important facts about radiosynovectomy that may help rheumatologists in their daily clinical practice.

  16. Radionuclide transport in the Yenisei River

    CERN Document Server

    Vakulovsky, S M; Kabanov, A I

    2012-01-01

    Data characterizing the pollution of the Yenisei River (water and bottom sediment) by radionuclide resulting from the use of the river water for cooling industrial reactors in the Mining-Chemical Complex are presented. Studies have been made of the contamination of the river during the period when reactors with direct flow cooling were used and after these were shut down. Distinctive features of the migration of radionuclide in the Yenisei are noted, in particular, their distribution between the solid and liquid phases. The amounts of 137Cs, 65Zn, 60Co, 54Mn, and 152Eu in the channel are determined from the effluent discharge site to Dudinka port. The rate of continuous self removal of 137Cs is estimated to be 0.19 1/year, corresponding to a half purification time of 3.6 years for a 600 km long segment of the river bed.

  17. Radionuclide synovectomy – essentials for rheumatologists

    Science.gov (United States)

    Felis-Giemza, Anna; Kobylecka, Małgorzata

    2016-01-01

    Radionuclide synovectomy is a minimally invasive method of treating persistent joint inflammation. It involves intra-articular injection of radioactive colloids which induce necrosis and fibrosis of hypertrophic synovial membrane. The most common indication for radiosynovectomy is rheumatoid arthritis, although patients with seronegative spondyloarthropathies, unclassified arthritis, haemophilic arthropathy and other less common arthropathies can also benefit from this method. Radiosynovectomy is safe, well tolerated and efficacious. About 70–80% of patients respond well to the therapy. However, the therapeutic effects are considerably worse in patients with co-existent osteoarthritis and advanced joint degeneration. Despite its advantages, radionuclide synovectomy is not performed as often as it could be, so greater knowledge and understanding of this method are needed. The authors present the most important facts about radiosynovectomy that may help rheumatologists in their daily clinical practice. PMID:27504020

  18. Decline of radionuclides in Columbia River biota

    Energy Technology Data Exchange (ETDEWEB)

    Cushing, C.E.; Watson, D.G.; Scott, A.J.; Gurtisen, J.M.

    1980-03-01

    In January 1971, the last of nine plutonium production reactors using direct discharge of once-through cooling waters into the Columbia River was closed. Sampling was initiated at three stations on the Columbia River to document the decline of the radionuclide body burdens in the biota of the Columbia River ecosystem. The data show that in a river-reservoir complex, the measurable body burden of fission-produced radionuclides decreased to essentially undetectable levels within 18 to 24 mo after cessation of discharge of once-through cooling water into the river. On the basis of data from the free-flowing station, we believe that this decrease would be even more rapid in an unimpounded river.

  19. Radionuclides accumulation in milk and its products

    Energy Technology Data Exchange (ETDEWEB)

    Marmuleva, N.I.; Barinov, E.Y.; Petukhov, V.L. [Novosibirsk State Agrarian University (Russian Federation)

    2003-05-01

    The problem of radioactive pollution is extremely urgent in Russia in connection with presence of territories polluted by radionuclides on places of nuclear tests, in zones around the enterprises on production, processing and storage of radioactive materials, and also in areas of emergency pollution (Barakhtin, 2001). The aim of our investigation was a determination of the levels of the main radioactive elements - {sup 137}Cs and {sup 90}Sr in diary products. 363 samples of milk, dry milk, butter, cheese and yogurt from Novosibirsk region were examined. {sup 137}Cs level was 3.7 to 9.2 times higher than {sup 90}Sr one in milk, cheese and yogurt. At the same time the level of these radio-nuclides in butter was identical (8.03 Bk/kg). (authors)

  20. Improving cancer treatment with cyclotron produced radionuclides

    Energy Technology Data Exchange (ETDEWEB)

    Larson, S.M. Finn, R.D.

    1992-08-04

    This report describes the author's continuing long term goal of promoting nuclear medicine applications by improving the scientific basis for tumor diagnosis treatment and treatment follow-up based on the use of cyclotron produced radiotracers in oncology. The program has 3 interactive components: Radiochemistry /Cyclotron; Pharmacology; and Immunology. An essential strategy is as follows: novel radionuclides and radiotracers developed in the Radiochemistry/Cyclotron section under the DOE grant during the 1989--1992 grant period, will be employed in the Pharmacology and Immunology sections of the DOE grant during the 1992--1995 grant period. The development of novel radionuclides and tracers is of course useful in and of itself, but their utility is greatly enhanced by the interaction with the immunology and pharmacology components of the program.

  1. Cadastral valuation of lands polluted with radionuclides

    Science.gov (United States)

    Makarov, O. A.; Tsvetnov, E. V.; Shcheglov, A. I.; Romashkina, A. D.; Ermiyaev, Ya. R.

    2016-11-01

    The major method to correct the cadastral value of land for contamination with radionuclides is to reduce it by the sum of expenses necessary for land remediation and for special measures ensuring the obtaining of agricultural and forestry products satisfying safety norms. Lands contaminated with radionuclides and used in agriculture and forestry are often removed from the system of land taxation. In this case, their cadastral value becomes an excessive element of the state cadaster of real estate. An approach toward cadastral valuation of such lands suggested by the authors assumes the creation of a system of compensation payments as the main source of financing of land rehabilitation and soil conservation measures. An original system of calculation of such payments has been tested for radioactively contaminated lands in Plavsk district of Tula oblast. It is argued that compensation payments for radioactively contaminated agrocenoses should be higher than those for natural cenoses.

  2. Radionuclide methods of tumor diagnosis in ophthalmology

    Energy Technology Data Exchange (ETDEWEB)

    Dubinskaya, L.R. (Nauchno-Issledovatel' skij Inst. Glaznykh boleznej (USSR))

    1982-08-01

    The radionuclide methods used in opthalmology for diagnosis of eyes and orbit tumors are described: radiophosphorus indication, method of gamma-topography, method of external radiometry, method of blood circulation study in organ of vision. Diagnostic value was determined of such radiopharmaceuticals as /sup 32/P-phosphate, /sup 67/Ga-citrate, /sup 131/I-Ralbumin, /sup 197/Hg-neohydrine, /sup 125/I-fluorescein, /sup 75/Se-methionine, sup(99m)Tc-pertechnete and others. The conclusion was drawn that the considered radionuclides and radiopharmaceuticals were not perfect indicators for diagnosis of different tumors of organ of vision. Simultaneous using of several radiopharmaceuticals with the aim of increasing information content of described methods is recommended.

  3. Radionuclide evaluation of renal artery dilatation

    Energy Technology Data Exchange (ETDEWEB)

    Born, M.L.; Gerlock, A.J. Jr.; Goncharenko, V.; Hollifield, J.W.; MacDonell, R.C. Jr.

    1981-01-01

    Radionuclide studies were used in three patients to evaluate renal perfusion and function within 24 hours following transluminal dilatation. In one patient, technetium-99 m pertechnetate showed good renal perfusion one and 12 hours after a post-dilatation arteriogram had shown a renal artery intimal defect. Improved clearance of iodine-131 ortho-iodohippurate from the blood demonstrated an increase in renal function 18 hours following dilatation of a stenosis at a renal allograft anastomosis in the second patient, while technetium-99 m-labeled DTPA showed an improved total glomerular filtration rate 24 hours after dilatation of a saphenous vein bypass graft in the third patient. It was concluded that renal radionuclide studies are of benefit in evaluating patients in the immediate post-dilatation period.

  4. Hybrid adsorptive membrane reactor

    Science.gov (United States)

    Tsotsis, Theodore T. (Inventor); Sahimi, Muhammad (Inventor); Fayyaz-Najafi, Babak (Inventor); Harale, Aadesh (Inventor); Park, Byoung-Gi (Inventor); Liu, Paul K. T. (Inventor)

    2011-01-01

    A hybrid adsorbent-membrane reactor in which the chemical reaction, membrane separation, and product adsorption are coupled. Also disclosed are a dual-reactor apparatus and a process using the reactor or the apparatus.

  5. Hybrid adsorptive membrane reactor

    Science.gov (United States)

    Tsotsis, Theodore T.; Sahimi, Muhammad; Fayyaz-Najafi, Babak; Harale, Aadesh; Park, Byoung-Gi; Liu, Paul K. T.

    2011-03-01

    A hybrid adsorbent-membrane reactor in which the chemical reaction, membrane separation, and product adsorption are coupled. Also disclosed are a dual-reactor apparatus and a process using the reactor or the apparatus.

  6. Radionuclide release calculations for SAR-08

    Energy Technology Data Exchange (ETDEWEB)

    Thomson, Gavin; Miller, Alex; Smith, Graham; Jackson, Duncan (Enviros Consulting Ltd, Wolverhampton (United Kingdom))

    2008-04-15

    Following a review by the Swedish regulatory authorities of the post-closure safety assessment of the SFR 1 disposal facility for low and intermediate waste (L/ILW), SAFE, the SKB has prepared an updated assessment called SAR-08. This report describes the radionuclide release calculations that have been undertaken as part of SAR-08. The information, assumptions and data used in the calculations are reported and the results are presented. The calculations address issues raised in the regulatory review, but also take account of new information including revised inventory data. The scenarios considered include the main case of expected behaviour of the system, with variants; low probability releases, and so-called residual scenarios. Apart from these scenario uncertainties, data uncertainties have been examined using a probabilistic approach. Calculations have been made using the AMBER software. This allows all the component features of the assessment model to be included in one place. AMBER has been previously used to reproduce results the corresponding calculations in the SAFE assessment. It is also used in demonstration of the IAEA's near surface disposal assessment methodology ISAM and has been subject to very substantial verification tests and has been used in verifying other assessment codes. Results are presented as a function of time for the release of radionuclides from the near field, and then from the far field into the biosphere. Radiological impacts of the releases are reported elsewhere. Consideration is given to each radionuclide and to each component part of the repository. The releases from the entire repository are also presented. The peak releases rates are, for most scenarios, due to organic C-14. Other radionuclides which contribute to peak release rates include inorganic C-14, Ni-59 and Ni-63. (author)

  7. Radionuclide Air Emission Report for 2008

    Energy Technology Data Exchange (ETDEWEB)

    Wahl, Linnea

    2009-05-21

    Berkeley Lab operates facilities where radionuclides are handled and stored. These facilities are subject to the U.S. Environmental Protection Agency (EPA) radioactive air emission regulations in Code of Federal Regulations (CFR) Title 40, Part 61, Subpart H (EPA 1989). Radionuclides may be emitted from stacks or vents on buildings where radionuclide production or use is authorized or they may be emitted as diffuse sources. In 2008, all Berkeley Lab sources were minor sources of radionuclides (sources resulting in a potential dose of less than 0.1 mrem/yr [0.001 mSv/yr]). These minor sources include more than 100 stack sources and one source of diffuse emissions. There were no unplanned emissions from the Berkeley Lab site. Emissions from minor sources (stacks and diffuse emissions) either were measured by sampling or monitoring or were calculated based on quantities used, received for use, or produced during the year. Using measured and calculated emissions, and building-specific and common parameters, Laboratory personnel applied the EPA-approved computer code, CAP88-PC, to calculate the effective dose equivalent to the maximally exposed individual (MEI). The effective dose equivalent from all sources at Berkeley Lab in 2008 is 5.2 x 10{sup -3} mrem/yr (5.2 x 10{sup -5} mSv/yr) to the MEI, well below the 10 mrem/yr (0.1 mSv/yr) dose standard. The location of the MEI is at the University of California (UC) Lawrence Hall of Science, a public science museum about 1500 ft (460 m) east of Berkeley Lab's Building 56. The estimated collective effective dose equivalent to persons living within 50 mi (80 km) of Berkeley Lab is 1.1 x 10{sup -1} person-rem (1.1 x 10{sup -3} person-Sv) attributable to the Lab's airborne emissions in 2008.

  8. Loading technique for preparing radionuclide containing nanoparticles

    DEFF Research Database (Denmark)

    2011-01-01

    Source: US2012213698A The present invention relates to a novel composition and method for loading delivery systems such as liposome compositions with radionuclides useful in targeted diagnostic and/or therapy of target site, such as cancerous tissue and, in general, pathological conditions associ...... of positron emission tomography (PET) imaging technique. One specific aspect of the invention is directed to a method of producing nanoparticles with desired targeting properties for diagnostic and/or radio-therapeutic applications....

  9. Radionuclide Air Emission Report for 2009

    Energy Technology Data Exchange (ETDEWEB)

    Wahl, Linnea

    2010-06-01

    Berkeley Lab operates facilities where radionuclides are handled and stored. These facilities are subject to the EPA radioactive air emission regulations in 40CFR61, Subpart H (EPA 1989). Radionuclides may be emitted from stacks or vents on buildings where radionuclide production or use is authorized or they may be emitted as diffuse sources. In 2009, all Berkeley Lab sources were minor sources of radionuclides (sources resulting in a potential dose of less than 0.1 mrem/yr [0.001 mSv/yr]). These minor sources included more than 100 stack sources and one source of diffuse emissions. There were no unplanned emissions from the Berkeley Lab site. Emissions from minor sources (stacks and diffuse emissions) either were measured by sampling or monitoring or were calculated based on quantities used, received for use, or produced during the year. Using measured and calculated emissions, and building-specific and common parameters, Laboratory personnel applied the EPA-approved computer code, CAP88-PC, to calculate the effective dose equivalent to the maximally exposed individual (MEI). The effective dose equivalent from all sources at Berkeley Lab in 2009 is 7.0 x 10{sup -3} mrem/yr (7.0 x 10{sup -5} mSv/yr) to the MEI, well below the 10 mrem/yr (0.1 mSv/yr) dose standard. The location of the MEI is at the University of California (UC) Lawrence Hall of Science, a public science museum about 1500 ft (460 m) east of Berkeley Lab's Building 56. The estimated collective effective dose equivalent to persons living within 50 mi (80 km) of Berkeley Lab is 1.5 x 10{sup -1} person-rem (1.5 x 10{sup -3} person-Sv) attributable to the Lab's airborne emissions in 2009.

  10. Adsorption properties of CdS-CdTe system semiconductors

    Science.gov (United States)

    Kirovskaya, I. A.; Nor, P. E.

    2013-12-01

    The adsorption of carbon(II) oxide and ammonia on nanofilms of solid solutions and binary compounds of the CdS-CdTe system is studied by means of piezoquartz microweighing, FTIR IR, and measuring electroconductivity. Allowing for the conditions and composition of semiconductor systems, we determine the mechanisms and principles of adsorption processes by analyzing the α p = f( T), α T = f( p), and α T = f( t) experimental dependences; IR spectra; the thermodynamic and kinetic characteristics of adsorption; the acid-base, electrophysical, and other characteristics of adsorbents; the electron nature of adsorbate molecules; and the obtained acid-base characteristics: the composition and adsorption characteristics and composition state diagrams. Previous statements on the nature and retention of local active centers responsible for adsorption and catalytic processes upon changes in their habitus and composition (as components of systems of the AIIIBV-AIIBVI and AIIBVI-AIIBVI types) on the surface of diamond-like semiconductors are confirmed. Specific features of the behavior of (CdS) x (CdTe)1 - x solid solutions are identified in addition to general features with binary compounds (CdS, CdTe), as is demonstrated by the presence of critical points on acid-base characteristics-composition and adsorption characteristics-composition diagrams. On the basis of these diagrams, the most active adsorbents (with respect to CO and NH3) used in designing highly sensitive and selective sensors are identified.

  11. Concrete Property and Radionuclide Migration Tests

    Energy Technology Data Exchange (ETDEWEB)

    Wellman, Dawn M.; Mattigod, Shas V.; Powers, Laura; Parker, Kent E.; Clayton, Libby N.; Wood, Marcus I.

    2008-10-01

    The Waste Management Project provides safe, compliant, and cost-effective waste management services for the Hanford Site and the DOE Complex. Part of theses services includes safe disposal of LLW and MLLW at the Hanford Low-Level Waste Burial Grounds (LLBG) in accordance with the requirements listed in DOE Order 435.1, Radioactive Waste Management. To partially satisfy these requirements, a Performance Assessment (PA) analyses were completed and approved. DOE Order 435.1 also requires that continuing data collection be conducted to enhance confidence in the critical assumptions used in these analyses to characterize the operational features of the disposal facility that are relied upon to satisfy the performance objectives identified in the Order. One critical assumption is that concrete will frequently be used as waste form or container material to control and minimize the release of radionuclide constituents in waste into the surrounding environment. Data was collected to (1) quantify radionuclide migration through concrete materials similar to those used to encapsulate waste in the LLBG, (2) measure the properties of the concrete materials, especially those likely to influence radionuclide migration, and (3) quantify the stability of U-bearing solid phases of limited solubility in concrete.

  12. Radionuclide content of Las Vegas wash sediments

    Energy Technology Data Exchange (ETDEWEB)

    Rudin, M.J.; Meyers, A.M.; Johnson, W.H. [Univ. of Nevada, Las Vegas, NV (United States)

    1996-06-01

    The Las Vegas Wash is an excavated waterway channel which drains all surface water and effluent discharge from sewage-treatment facilities from the greater Las Vegas Metropolitan Area to Lake Mead. Runoff and erosion processes are expected to transport man-made radioactivity that was deposited over the past several decades in the Las Vegas Valley. Additionally, radionuclides disposed of via the city`s sanitary system are expected to accumulate in the Wash sediments. Fine and coarse sediment samples were collected at 100 m intervals and analyzed to determine the distribution of alpha- and gamma-emitting radionuclides in the lower 5,500 in of the Las Vegas Wash. Results indicate little accumulation of long-lived fission products in upstream Wash sediments. However, trace amounts of fission products measured in downstream sediments suggest the resuspension and transport of radioactive particulate matter within the Wash. Levels of naturally-occurring radionuclides found in Wash sediments were found to be consistent with levels typically found in southeast Nevada soils.

  13. Fungi and ionizing radiation from radionuclides.

    Science.gov (United States)

    Dighton, John; Tugay, Tatyana; Zhdanova, Nelli

    2008-04-01

    Radionuclides in the environment are one of the major concerns to human health and ecotoxicology. The explosion at the Chernobyl nuclear power plant renewed interest in the role played by fungi in mediating radionuclide movement in ecosystems. As a result of these studies, our knowledge of the importance of fungi, especially in their mycorrhizal habit, in long-term accumulation of radionuclides, transfer up the food chain and regulation of accumulation by their host plants was increased. Micro-fungi have been found to be highly resilient to exposure to ionizing radiation, with fungi having been isolated from within and around the Chernobyl plant. Radioresistance of some fungal species has been linked to the presence of melanin, which has been shown to have emerging properties of acting as an energy transporter for metabolism and has been implicated in enhancing hyphal growth and directed growth of sensitized hyphae towards sources of radiation. Using this recently acquired knowledge, we may be in a better position to suggest the use of fungi in bioremediation of radioactively contaminated sites and cleanup of industrial effluent.

  14. 草鱼鱼鳞对对苯二酚的吸附特性及其机理%Adsorption Characteristics and Mechanism of Grass Carp Scales towards Hydroquinone

    Institute of Scientific and Technical Information of China (English)

    熊进; 汪海波; 欧其语; 李彦; 刘良忠; 张寒俊

    2011-01-01

    In the present study,grass carp scales were used to remove hydroquinone from aqueous solutions under different experimental conditions.The effects of pH,adsorbent dose,adsorption time,adsorption temperature and initial hydroquinone concentration on adsorption efficiency were systematically investigated to explore the optimal conditions for the removal of hydroquinone.Meanwhile,its adsorption mechanism was also elucidated.The results showed that the adsorbent grass scrap scales revealed good adsorption capacity towards hydroquinone and the optimal adsorption conditions were pH 7,25 ℃ adsorption temperature,0.5 g/L adsorbent dose,100 mg/L initial hydroquinone concentration and 8 h adsorption time.Under the optimal adsorption conditions,the adsorption amount of hydroquinone was 76.71 mg/g.Further,kinetic and thermodynamic analyses indicated that the adsorption of hydroquinone by grass carp scales was mostly a physical adsorption process,which was a multilayer adsorption and fitted well with a pseudo-second order kinetic model.Moreover,the Freundlich isotherm model could well describe the isothermal adsorption of hydroquinone onto grass carp scales.%以草鱼鱼鳞为原料制备生物吸附剂,通过静态吸附实验研究其对水溶液中对苯二酚的吸附性能,系统地考察pH值、吸附剂用量、对苯二酚初始质量浓度、吸附时间、吸附温度对鱼鳞吸附效果的影响,并通过吸附动力学和热力学分析,探讨鱼鳞吸附对苯二酚的吸附机理。结果表明,鱼鳞吸附剂对对苯二酚具良好的吸附效果,其最佳吸附条件为:当温度为25℃、吸附剂用量0.5g/L、对苯二酚溶液初始质量浓度为100mg/L、溶液体系pH7、吸附时间8h时,鱼鳞吸附剂的吸附容量可达到76.71mg/g。吸附热力学和动力学分析表明,鱼鳞对对苯二酚的吸附是以物理吸附为主的多层吸附,准二级动力学模型可以较好地反映这种吸附动力学行为,Freundlich等温吸附方程

  15. Adsorption Characteristics of 2,4-Dimethyphenol by Using Zeolite in Aqueous Phase%沸石分子筛对水中2,4-二甲基苯酚的吸附特性研究

    Institute of Scientific and Technical Information of China (English)

    魏健; 孔明昊; 宋永会; Jean-Stéphane PIC; 范冬琪

    2015-01-01

    以沸石分子筛为吸附剂,采用批次试验,研究静态吸附对水中2,4-二甲基苯酚(2,4-DMP)的吸附去除效果,比较了3种不同类型的沸石分子筛对2,4-DMP的吸附性能,选择其中吸附性能最好的沸石分子筛FAU-Y为吸附剂,分别考察了溶液初始pH、吸附剂投加量对吸附效果的影响,并对吸附动力学和吸附等温线进行了分析。结果表明,FAU-Y对2,4-DMP具有较大的吸附量,在2,4-DMP初始浓度为250 mg∕L,溶液初始pH为5.2,吸附剂投加量为5.0 g∕L时,室温条件下反应24 h可以达到吸附平衡状态,饱和吸附容量为48.22 mg∕g;初始pH为2.0~9.3时,对FAU-Y吸附2,4-DMP没有明显影响;吸附动力学和吸附等温线分析结果表明,二级动力学能更好地描述FAU-Y对2,4-DMP的吸附,Langmuir-Freundlich吸附等温线对吸附平衡数据的拟合优于Langmuir吸附等温线和Freundlich吸附等温线。%The adsorption removal of 2,4-dimethyphenol (2,4-DMP) in aqueous phase was investigated by using zeolite in a batch statistic adsorption system .The 2,4-DMP adsorption capabilities of three different zeolites were compared , and FAU-Y zeolite was chosen as the adsorbent for its best adsorption capabilities .The effects of initial pH and adsorbent dosage on 2 ,4-DMP adsorption were investigated respectively , and the adsorption kinetics and isotherms analyzed.The results showed that FAU-Y zeolite had high adsorption ability for 2, 4-DMP.The equilibrium of the adsorption process was established in about 24 h under the conditions of initial 2, 4-DMP concentration 250 mg∕L, initial pH 5.2, FAU-Y zeolite dosage 5.0 g∕L and temperature 20 ℃, with a saturated adsorption capability of 48.22 mg∕g.The initial pH from 2.0 to 9.3 had no significant influence on 2,4-DMP adsorption removal .The comparison of adsorption kinetic models showed that the adsorption process was

  16. Uses of alpha particles, especially in nuclear reaction studies and medical radionuclide production

    Energy Technology Data Exchange (ETDEWEB)

    Qaim, Syed M.; Spahn, Ingo; Scholten, Bernhard; Neumaier, Bernd [Forschungszentrum Juelich GmbH (Germany). Inst. fuer Neurowissenschaften und Medizin (INM), Nuklearchemie (INM-5)

    2016-11-01

    Alpha particles exhibit three important characteristics: scattering, ionisation and activation. This article briefly discusses those properties and outlines their major applications. Among others, α-particles are used in elemental analysis, investigation and improvement of materials properties, nuclear reaction studies and medical radionuclide production. The latter two topics, dealing with activation of target materials, are treated in some detail in this paper. Measurements of excitation functions of α-particle induced reactions shed some light on their reaction mechanisms, and studies of isomeric cross sections reveal the probability of population of high-spin nuclear levels. Regarding medical radionuclides, an overview is presented of the isotopes commonly produced using α-particle beams. Consideration is also given to some routes which could be potentially useful for production of a few other radionuclides. The significance of α-particle induced reactions to produce a few high-spin isomeric states, decaying by emission of low-energy conversion or Auger electrons, which are of interest in localized internal radiotherapy, is outlined. The α-particle beam, thus broadens the scope of nuclear chemistry research related to development of non-standard positron emitters and therapeutic radionuclides.

  17. Bioavailability of anthropogenic radionuclides in mussels along the french mediterranean coast

    Energy Technology Data Exchange (ETDEWEB)

    Thebault, H.; Arnaud, M.; Charmasson, S.; Andral, B.; Dimeglio, Y.; Barker, E. [Institut de Radioprotection et de Surete Nucleaire. IFREMER, Laboratoire d' Etudes Radioecologiques Continentales et de la Mediterranee, 83 - La Seyne-sur-Mer (France)

    2004-07-01

    Within the framework of the Water Management Master-plan, a bio-indicator network (RINBIO) was deployed all along the French Mediterranean coast (1,800 km), using man-made cages containing mussels (Mytilus galloprovincialis) to assess contamination by heavy metals, persistent organic products and radionuclides. The caging technique compensated for the scarcity of natural shellfish stocks in significant parts of the coast and enable comparison between sites regardless of their physicochemical and trophic characteristics. Among the 103 stations of the entire program, 40 were selected for the measurement of anthropogenic radionuclides by high-efficiency gamma-spectrometry. Biometrics parameters of the each mussel samples, including 'condition index' as an indicator of soft part growth, will be correlated with radionuclides activities, allowing to correct raw data from differences in bioaccumulation between the various sites in relation to their trophic levels. A comprehensive picture of the distribution of radionuclides at a such a large spatial scale will be provided and the contribution of the Rhone river input, so far the main source for the coastal zone, will be investigated. (author)

  18. Horizontal and vertical characterization of radionuclides and minerals in river sediments.

    Science.gov (United States)

    Ramasamy, V; Suresh, G; Meenakshisundaram, V; Ponnusamy, V

    2011-01-01

    The natural radionuclide ((238)U, (232)Th and (40)K) contents and mineral characteristics have been analyzed for the different depth sediment samples of Ponnaiyar River with an aim of evaluating the radiation hazard and its relation to specific minerals. To know the complete radiological characteristics, the radiological indices have been calculated and compared with recommended values. In an FTIR study, the extinction coefficient and crystallinity index is calculated to find the relative distribution of major minerals and the crystallinity of quartz, respectively. Both horizontal and vertical distributions of radionuclides and major minerals are studied. Multivariate statistical analyses (cluster and factor) were carried out to determine the relationship between the radioactivity and the minerals. Statistical analyses suggest that the kaolinite is the major mineral to increase the level of radioactivity in the river sediments. Copyright © 2010 Elsevier Ltd. All rights reserved.

  19. National Low-Level Waste Management Program radionuclide report series. Volume 2, Niobium-94

    Energy Technology Data Exchange (ETDEWEB)

    Adams, J.P.; Carboneau, M.L.

    1995-04-01

    The Purpose of the National Low-Level Waste Management Program Radionuclide Report Series is to provide information to, state representatives and developers of low-level radioactive waste disposal facilities about the radiological chemical, and physical characteristics of selected radionuclides and their behavior in the low-level radioactive waste disposal facility environment. Extensive surveys of available literature provided information used to produce this series of reports and an introductory report. This report is Volume 11 of the series. It outlines the basic radiological, chemical, and physical characteristics of niobium-94, waste types and forms that contain it, and its behavior in environmental media such as soils, plants, groundwater, air, animals and the human body.

  20. Modeling adsorption: Investigating adsorbate and adsorbent properties

    Science.gov (United States)

    Webster, Charles Edwin

    1999-12-01

    Surface catalyzed reactions play a major role in current chemical production technology. Currently, 90% of all chemicals are produced by heterogeneously catalyzed reactions. Most of these catalyzed reactions involve adsorption, concentrating the substrate(s) (the adsorbate) on the surface of the solid (the adsorbent). Pore volumes, accessible surface areas, and the thermodynamics of adsorption are essential in the understanding of solid surface characteristics fundamental to catalyst and adsorbent screening and selection. Molecular properties such as molecular volumes and projected molecular areas are needed in order to convert moles adsorbed to surface volumes and areas. Generally, these molecular properties have been estimated from bulk properties, but many assumptions are required. As a result, different literature values are employed for these essential molecular properties. Calculated molar volumes and excluded molecular areas are determined and tabulated for a variety of molecules. Molecular dimensions of molecules are important in the understanding of molecular exclusion as well as size and shape selectivity, diffusion, and adsorbent selection. Molecular dimensions can also be used in the determination of the effective catalytic pore size of a catalyst. Adsorption isotherms, on zeolites, (crystalline mineral oxides) and amorphous solids, can be analyzed with the Multiple Equilibrium Analysis (MEA) description of adsorption. The MEA produces equilibrium constants (Ki), capacities (ni), and thermodynamic parameters (enthalpies, ΔHi, and entropies, ΔSi) of adsorption for each process. Pore volumes and accessible surface areas are calculated from the process capacities. Adsorption isotherms can also be predicted for existing and new adsorbate-adsorbent systems with the MEA. The results show that MEA has the potential of becoming a standard characterization method for microporous solids that will lead to an increased understanding of their behavior in gas

  1. Production, separation and speciation of no-carrier-added Hg radionuclides using greener methodologies

    Energy Technology Data Exchange (ETDEWEB)

    Mandal, S.; Nayak, D. [Chemical Sciences Div., Saba Inst. of Nuclear Physics, Kolkata (India)

    2010-07-01

    Species dependent studies of no-carrier-added (nca) mercury were carried out using radioanalytical technique coupled with two greener analytical methodologies. The adsorption of nca {sup 195mg}Hg and {sup 197m}Hg radionuclides on chitosan biopolymer and cloud point extraction (CPE) was studied to develop environmentally sustainable speciation methodologies at ultra trace level. Species information was obtained by comparing the adsorption profile of nca radiomercury on chitosan biopolymer with the software code CHEAQS PRO. Results obtained from the adsorption study were validated by CPE technique using non ionic surfactant and mixed micelle. Both the experiments established that nca Hg existed as Hg(II). The experimental results support the presence of HgCl{sub 2} species over the pH range 2-4, whereas Hg(OH){sub 2} is the main species over the pH range 6-8. Chitosan biopolymer and mixed micelle [Triton-X-114 and cetyltrimethylammonium bromide (CTAB)] constitute an efficient reagent for the preconcentration of ultra trace level mercury. (orig.)

  2. Adsorption characteristics of sulfide onto the activated sludge of municipal wastewater treatment plants. OUYAN G%城市污水处理厂污泥对水中硫化物的吸附特性

    Institute of Scientific and Technical Information of China (English)

    欧阳云; 席劲瑛; 王智超; 胡洪营

    2014-01-01

    为研究城市污水厂污泥对水中硫化物的吸附特性,从3座城市污水处理厂采集回流污泥,考察了硫化物浓度、温度、pH值和其他离子对污泥吸附硫化物的影响.结果表明,污水厂回流污泥对硫化物的吸附等温线可以用 Langmuir 方程很好地描述,其最大硫化物吸附量为15~27mg/g-干污泥.在温度为5~35℃条件下,吸附量随温度上升而增加,表明该吸附为吸热过程.pH值在2~7范围内,pH值对污泥吸附硫化物的影响不大,当pH值低于2时,污泥对硫化物的吸附量随pH降低显著减小.硫化物可能以离子形式被污泥吸附,该过程为化学吸附过程.水中存在0~25mg/L Cl-或0~12mg/L SO2-4不影响污泥对硫化物的吸附量.%In this study, activated sludge samples were collected from 3municipal wastewater treatment plants (WWTP) and the performance and impacting factors of sulfides adsorption onto the activated sludge were investigated. The impacting factors include sulfides concentration, temperature, pH and other anions. Adsorption isotherm of sulfide onto the activated sludge can be well described by Langmuir equation. The maximum sulfide adsorption capacity was 15~27mg/g-dry sludge. At the temperatures ranging from 5to 35℃, adsorption capacity increased by the rise in temperature and this implies the sulfides adsorption was an endothermic process. The pH value had little effect on the adsorption capacity from 2to 7. But the sulfides adsorption capacity decreased significantly when pH was lower than 2. Sulfides were adsorbed by activated sludge as anions (HS- and S2-) and it was a chemical adsorption process. Cl- ranging from 0 to 25mg/LorSO2- 4 ranging from 0 to 12mg/L did not affect the sulfides adsorption capacity.

  3. Adsorption Characteristics of 2-MIB Onto Powdered Activated Carbons in the Reservoir Type Source Water%PAC对水库型水源水中嗅味物质2-MIB的吸附特性

    Institute of Scientific and Technical Information of China (English)

    宋武昌; 李星; 潘章斌; 杨艳玲; 孙韶华; 贾瑞宝

    2015-01-01

    为解决水库型水源水中季节性藻致嗅味物质的应急处理问题,研究了不同水质条件下粉末活性炭( PAC)对水中嗅味物质二甲基异崁醇(2-MIB)的吸附动力学模型和吸附热力学模型,考察了2类水库型水源水中有机物对吸附作用的影响。结果表明:在试验浓度范围内,纯水、原水A和原水B中PAC对2-MIB的吸附过程符合准二级反应动力学模型,吸附等温线符合修正的Freundlich方程,且吸附速率和吸附容量依次降低;原水A、B中PAC对2-MIB的吸附能力显著降低,但原水B中2-MIB在活性炭表面的吸附势能比原水A中的强,这可能主要是由原水中分子质量<500 u的小分子有机物引起的微孔吸附竞争及其极性造成的。%In order to solve the problem of seasonal pollution of reservoir water by taste and odor caused by algae, the adsorption kinetics and isothermal adsorption modeling of 2-methylisoborneol (2-MIB) by powdered activated carbons ( PAC) in different water quality were studied, and the adsorption effects of organic matter in two kinds of reservoir water were investigated. Results showed that, in the range of test concentration, the adsorption processes followed pseudo-second-order kinetics equation and the modified Freundlich equation in pure water, raw water A and B, and the adsorption rate and adsorption capacity reduced in turn. The adsorption capacity decreased significantly in raw water A and B, but the adsorption potential energies of 2-MIB on activated carbon in raw water B was stronger than that of raw water A, due to the micropore competitive adsorption and polarity caused by the reservoir water of small organic molecules with relative molecular weight of <500 u.

  4. Adsorption of gases on carbon molecular sieves

    Energy Technology Data Exchange (ETDEWEB)

    Vyas, S.N.; Patwardhan, S.R.; Vijayalakshmi, S. (Indian Inst. of Technology, Bombay (India). Dept. of Chemical Engineering); Ganesh, K.S. (Hindustan Petroleum Corp. Ltd., Bombay (India))

    1994-12-01

    Adsorption on carbon molecular sieves (CMS) prepared by coke deposition has become an interesting area of adsorption due to its microporous nature and favorable separation factor on size and shape selectivity basis for many gaseous systems. In the present work CMS was synthesized from coconut shell through three major steps, namely, carbonization, activation, and coke deposition by hydrocarbon cracking. The crushed, washed, and sieved granules of coconut shell (particle size 2--3 mm) were pretreated with sodium silicate solution and oven-dried at 150 C to create the inorganic sites necessary for coke deposition. Carbonization and activation of the dried granules were carried out at 800 C, for 30 min each. The activated char thus produced was subjected to hydrocarbon cracking at 600 C for periods varying from 30 to 180 min. The product samples were characterized in terms of adsorption isotherm, kinetic adsorption curve, surface area, pore volume, pore size distribution, and characteristic energy for adsorption by using O[sub 2], N[sub 2], C[sub 2]H[sub 2], CO[sub 2], C[sub 3]H[sub 6], and CH[sub 4].

  5. Advanced adsorption cooling cum desalination cycle: A thermodynamic framework

    KAUST Repository

    Chakraborty, Anutosh

    2011-01-01

    We have developed a thermodynamic framework to calculate adsorption cooling cum desalination cycle performances as a function of pore widths and pore volumes of highly porous adsorbents, which are formulated from the rigor of thermodynamic property surfaces of adsorbent-adsorbate system and the adsorption interaction potential between them. Employing the proposed formulations, the coefficient of performance (COP) and overall performance ratio (OPR) of adsorption cycle are computed for various pore widths of solid adsorbents. These results are compared with experimental data for verifying the proposed thermodynamic formulations. It is found from the present analysis that the COP and OPR of adsorption cooling cum desalination cycle is influenced by (i) the physical characteristics of adsorbents, (ii) characteristics energy and (iii) the surface-structural heterogeneity factor of adsorbent-water system. The present study confirms that there exists a special type of adsorbents having optimal physical characteristics that allows us to obtain the best performance.

  6. Methods of increasing the performance of radionuclide generators used in nuclear medicine: daughter nuclide build-up optimisation, elution-purification-concentration integration, and effective control of radionuclidic purity.

    Science.gov (United States)

    Le, Van So; Do, Zoe Phuc-Hien; Le, Minh Khoi; Le, Vicki; Le, Natalie Nha-Truc

    2014-06-10

    Methods of increasing the performance of radionuclide generators used in nuclear medicine radiotherapy and SPECT/PET imaging were developed and detailed for 99Mo/99mTc and 68Ge/68Ga radionuclide generators as the cases. Optimisation methods of the daughter nuclide build-up versus stand-by time and/or specific activity using mean progress functions were developed for increasing the performance of radionuclide generators. As a result of this optimisation, the separation of the daughter nuclide from its parent one should be performed at a defined optimal time to avoid the deterioration in specific activity of the daughter nuclide and wasting stand-by time of the generator, while the daughter nuclide yield is maintained to a reasonably high extent. A new characteristic parameter of the formation-decay kinetics of parent/daughter nuclide system was found and effectively used in the practice of the generator production and utilisation. A method of "early elution schedule" was also developed for increasing the daughter nuclide production yield and specific radioactivity, thus saving the cost of the generator and improving the quality of the daughter radionuclide solution. These newly developed optimisation methods in combination with an integrated elution-purification-concentration system of radionuclide generators recently developed is the most suitable way to operate the generator effectively on the basis of economic use and improvement of purposely suitable quality and specific activity of the produced daughter radionuclides. All these features benefit the economic use of the generator, the improved quality of labelling/scan, and the lowered cost of nuclear medicine procedure. Besides, a new method of quality control protocol set-up for post-delivery test of radionuclidic purity has been developed based on the relationship between gamma ray spectrometric detection limit, required limit of impure radionuclide activity and its measurement certainty with respect to

  7. B,P单掺杂和共掺杂石墨烯对O,O2,OH和OOH吸附特性的密度泛函研究∗%Density functional study on the adsorption characteristics of O, O2, OH, and OOH of B-, P-doped, and B, P co dop ed graphenes

    Institute of Scientific and Technical Information of China (English)

    孙建平; 周科良; 梁晓东

    2016-01-01

    Over past years, the excessive use of fossil fuel has posed serious problems such as greenhouse effect and envi-ronmental pollution, which threaten human life. Regarded as an ideal substitution for traditional internal combustion engine, low temperature proton exchange membrane fuel cell (PEMFC) converts chemical energy through electrode reaction directly into electrical energy with high efficiency and low pollution. However, the main problem behind the industrialization of PEMFC, is that oxygen reduction reaction (ORR) occurring on the cathode needs precious metal platinum (Pt) as catalyst, which has a limited reserve and is costly. Owing to high activity and stability, the graphenes doped with non-metal B and P, have proven to be excellent alternatives to Pt experimentally. However, the relevant theoretical work is scarce. Adsorptions of the ORR intermediates, i.e., O, O2, OH, and OOH, of doped graphenes are essential for the cathode reaction, which also bring some difficulties to the next step reaction. Therefore, in this paper, based on density functional theory, the adsorption characteristics of O, O2, OH, and OOH of B-doped, P-doped and B, P-codoped graphenes are studied using first-principles calculation code VASP first. By analyzing the adsorption energies, bond lengths, densities of states and charge transfers, the influences of the different dopants on the intermediates are evaluated. Then, the ORR steps are discussed, and the free energy change of each step is further given. The results show that for B-doped and P-doped graphenes, the adsorption energies of various intermediates exhibit similar linear relationships. The adsorption energy of OOH of P-doped graphene (3.26 eV) is much larger than that in B-doped grapheme (0.73 eV). The large adsorption energy of P-doped graphene is beneficial to the fracture reaction of O—O bond in OOH, while the small adsorption energy of B-doped graphene can promote the reaction of OH converting into water. Owing to the

  8. Remediation of radionuclide pollutants through biosorption - an overview

    Energy Technology Data Exchange (ETDEWEB)

    Das, Nilanjana [Environmental Biotechnology Division, School of Biosciences and Technology, VIT University, Vellore (India)

    2012-01-15

    The development of nuclear science and technology has led to the increase of nuclear wastes containing radionuclides to be released and disposed in the environment. Pollution caused by radionuclides is a serious problem throughout the world. To solve the problem, substantial research efforts have been directed worldwide to adopt sustainable technologies for the treatment of radionuclide containing wastes. Biosorption represents a technological innovation as well as a cost effective excellent remediation technology for cleaning up radionuclides from aqueous environment. A variety of biomaterials viz. algae, fungi, bacteria, plant biomass, etc. have been reported for radionuclide remediation with encouraging results. This paper reviews the achievements and current status of radionuclide remediation through biosorption which will provide insights into this research frontier. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  9. Modeling the Hydrogeochemical Transport of Radionuclides through Engineered Barriers System in the Proposed LLW Disposal Site of Taiwan - 12082

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Wen-Sheng [Hydrotech Research Institute, National Taiwan University, Taipei, Taiwan (China); Liu, Chen-Wuing; Tsao, Jui-Hsuan [Department of Bioenvironmental Systems Engineering, National Taiwan University, Taipei, Taiwan (China); Li, Ming-Hsu [Institute of Hydrological and Oceanic Sciences, National Central University, Jhongli, Taiwan (China)

    2012-07-01

    A proposed site for final disposal of low-level radioactive waste located in Daren Township of Taitung County along the southeastern coast has been on the selected list in Taiwan. The geology of the Daren site consists of argillite and meta-sedimentary rocks. A mined cavern design with a tunnel system of 500 m below the surface is proposed. Concrete is used as the main confinement material for the engineered barrier. To investigate the hydrogeochemical transport of radionuclides through engineered barriers system, HYDROGEOCHEM5.0 model was applied to simulate the complex chemical interactions among radionuclides, the cement minerals of the concrete, groundwater flow, and transport in the proposed site. The simulation results showed that the engineered barriers system with the side ditch efficiently drained the ground water and lowered the concentration of the concrete degradation induced species (e.g., hydrogen ion, sulfate, and chloride). The velocity of groundwater observed at side ditch gradually decreased with time due to the fouling of pore space by the mineral formation of ettringite and thaumasite. The short half-life of Co-60, Sr-90 and Cs-137 significantly reduced the concentrations, whereas the long half-life of I-129(1.57x10{sup 7} years) and Am-241(432 years) remain stable concentrations at the interface of waste canister and concrete barrier after 300 years. The mineral saturation index (SI) was much less than zero due to the low aqueous concentration of radionuclide, so that the precipitation formation of Co-60, Sr-90, I-129, Cs-137 and Am-241 related minerals were not found. The effect of adsorption/desorption (i.e., surface complexation model) could be a crucial geochemical mechanism for the modeling of liquid-solid phase behavior of radionuclide in geochemically dynamic environments. Moreover, the development of advanced numerical models that are coupled with hydrogeochemical transport and dose assessment of radionuclide is required in the future

  10. Influence of speciation on the radionuclide uptake of plants; Einfluss der Speziation auf die Radionuklidaufnahme von Pflanzen

    Energy Technology Data Exchange (ETDEWEB)

    Tawussi, Frank

    2017-01-25

    The bioavailability for plants and uptake of radionuclides depend on various factors. The knowledge of the chemical and physical processes serves as basis for the transfer to different plant parts and finally for the estimation of the ingestion dose after consumption by man. Within the scope of the present work, the uptake of radionuclides was investigated in pea plants (Pisum sativum), paprika plants (Capsicum annuum) and potato plants (Solanum tuberosum) at low concentration (10{sup -5} to 10{sup -7} mol l{sup -1} for uranium and 10{sup -7} to 10{sup -9} mol l{sup -1} for plutonium) in hydroponic solution. Particular attention was paid to the speciation of radionuclides within the solution which was measured by time-resolved laser-induced fluorescence spectroscopy (TRLFS), capillary electrophoresis coupled to inductively-coupled-plasma mass-spectrometry (CE-ICP-MS), and theoretically calculated by the speciation code PHREEQC. The speciation, the solubility and therefore the plant availability of radionuclides mainly depend on the pH value and the redox potential of the solution. These parameters were monitored regularly. During the contamination period, the redox potential did not chance significantly. In contrast, the pH value showed characteristic changes depending on plants species. Especially in case of potato plants, the dissolved radionuclide fraction correlated with the changes of the pH value. In the plant roots, high amounts of radionuclides (10% to 50% of the added total quantity) were measured. Besides the uptake in the roots, the radionuclides can also adsorb to the exterior root surface. The transfer factor, which describes the Pu uptake ratio from the nutrient solution into the plant parts (dry mass), showed for the potato tubers values between 0.03 and 0.80 (Bq kg{sup -1}/ Bq l{sup -1}), depending on the initial Pu concentration. In addition of the complexing agent EDTA in solution (10{sup -4} mol l{sup -1}), the plutonium uptake increases up to 58

  11. Effect of Yellow Soil Components on Adsorption and Desorption Characteristics of Fluorine in Mountain Regions of Western Sichuan%川西山地黄壤组分对氟的吸附-解吸特征研究

    Institute of Scientific and Technical Information of China (English)

    夏丽; 夏建国

    2011-01-01

    以川西山地黄壤为例,采用选择溶解和模拟试验方法,研究黄壤各组分对F-的吸附与解吸特性。结果表明:黄壤各组分对F-的吸附可分为快速和慢速两个阶段,去除土壤相关组分后,平衡时间缩短,平均吸附速率变大,最大吸附量显著下降。随着初始浓度增大,吸附量呈增加趋势,吸附平衡液pH值上升。与未去除组分相比,经处理的样品对F-的吸附量均有一定程度的降低,其降低量由小到大的顺序为去无定形氧化铁/铝〉去有机质〉去游离氧化铁/铝。Langmuir、Freundlich、Temkin方程均可较好的拟合样品对F-的吸附,以Langm%The yellow soil collected from the Mountain Regions of Western Sichuan was used to investigate effect of yellow soil components on adsorption and desorption of F-by using selective dissolution and simulation methods.The results showed that adsorption rate by yellow soil components was composed of rapid and slow periods.The equilibrium time was shortened,average absorption rate was elevated and the max adsorption quantity was decreased significantly after removal of soil related components.The quantity of adsorption,the pH-value of equilibrium liquid increased with the increase of initial concentration.The samples of F-adsorption capacity was reduced after removal of components.The decrease of the larger order is: removing amorphous oxide iron/ aluminum removing O.Mremoving free oxide iron/ aluminum.The trial data of F-adsorption on samples of soil were better conform to Langmuir,Freundlich and Temkin equations,but the Langmuir equation was the best.The F-adsorbed by yellow soil could be mostly desorbed by 0.02 mol L-1 KCl solution.The specific adsorption capability to buffer was decreased with the increase of desorption rate after removal of soil components.The order is: removing free oxide iron/ aluminum removing O.Mremoving amorphous oxide iron/ aluminum original soil,which indicated the importance of soil

  12. Preparation of cucurbit [6] uril anchored silica gel and its adsorption characteristics of sulfamonomethoxine%固载化瓜环的制备及其对磺胺间甲氧嘧啶的吸附性能研究

    Institute of Scientific and Technical Information of China (English)

    靳涛; 陈德强; 刘云; 董元华; 乔洪涛; 陈晓流

    2013-01-01

    在微波无极灯下将烯氧基瓜环固载到巯基硅胶(MSG)上,制得固载化瓜环(ACB[6]-SG).通过红外光谱表征固载产物,并研究固载化瓜环对磺胺间甲氧嘧啶(SMM)的吸附性能.结果表明,SMM在固载化瓜环上的吸附基本在2 min内即可达到平衡;Henry方程和Freundlich方程均能较好地拟合SMM在固载化瓜环和巯基硅胶上的等温吸附曲线,但是SMM在固载化瓜环上的吸附主要是在瓜环中的分配,而SMM在巯基硅胶上的吸附则主要是多分子层的表面吸附作用;SMM在固载化瓜环上的平衡吸附量远大于在巯基硅胶上的平衡吸附量;SMM在两者上的吸附过程是一个放热过程,温度越低吸附效果越好.%Cucurbit [ 6 ] uril anchored silica gel ( ACB [ 6 ] -SG) was produced by anchoring perallyloxy-cucurbit [ 6 ] uril onto 3-mercaptopropyl-functionalized silica gel (MSG) under a microwave electrodeless lamp and was characterized by infrared spectrum analysis. The adsorption behaviors of sulfamonomethoxine (SMM) on ACB[6]-SG and MSG were studied. The results showed that the adsorption of SMM on ACB[6]-SG reached equilibrium in 2 min. The adsorption of SMM on ACB[6]-SG and MSG could be well described by both the Henry model and the Freundlich model. However, the adsorption of SMM on ACB[6]-SG was mainly partition processes of SMM in the cucurbit[6 ] uril, whereas the adsorption of SMM on MSG occurred mainly on the multilayer molecular surface of ACB[6]-SG. Furthermore, the adsorption amount of SMM on ACB[6]-SG at equilibrium was much higher than that on MSG. The adsorption of SMM on both ACB[6]-SG and MSG was an exothermic process, in which the lower the temperature was, the higher the adsorption efficiency.

  13. Activated Carbon Adsorption Properties of the Residual Matters in Textile Dyeing and Printing Secondary Effluent

    Institute of Scientific and Technical Information of China (English)

    TIAN Qing; LI Fang; LIU Fang; YANG Bo; CHEN Ji-hua

    2008-01-01

    The research employed the adsorption isotherm measurement, the batch kinetic adsorption and the rapid small-scale carbon column test (RSSCT) to find out the characteristics and main impacting factors of granular activated carbon (GAC) adsorption, in treating the textile dyeing-printing/polyester alkali de-weighting secondary effluent (TSE). The adsorption affinities and capacities for the organics surrogated by CODCr, color and UV254 (UV absorbency at λ= 254 nm) predicted by isotherm, small-scale-fixed bed were discussed. Adsorption rates for CODCr, color and UV254 are much different and carbon particle size dependent. The color adsorption rate and capacity should be taken as the main consideration factors in designing bio-activated carbon filter(BACF). The breakthrough of GAC adsorption column is mainly influenced by the low MW readily adsorbable organics in TSE. UVm is a good adsorption breakthrough indicator. The study provides References for BACFs' design and operation control in textile secondary effluent (TSE) tertiary treatment.

  14. Preparation of Adsorbent with Magnesium Sulfate and Straw Pulp Black Liquor and Its Phenol Adsorption Properties

    Institute of Scientific and Technical Information of China (English)

    GUO Lugang; WANG Haizeng

    2009-01-01

    A magnesia adsorbent was prepared from straw pulp black liquor and magnesium sulfate for the first time, and its adsorption of phenol from aqueous solution was examined. The characteristics of the adsorbent were tested through chemical analysis,surface analysis, X-ray diffraction and FT-IR spectroscopy. The effects of various factors, such as dose, adsorption time and adsorption temperature, on phenol adsorption behavior were studied. The results show that the adsorption processes can be fitted to the isotherm Langmuir model very well. It was found that the adsorption process was strongly influenced by temperature and the optimal temperature for phenol removal was 40 ℃. The optimum adsorption time was 10 min, and desorption would happen afterwards. Between the models of Langmuir and Freundlich, the adsorption process of phenol onto magnesia fitted the Langmuir equation better.

  15. Washout of particle-bound radionuclides for characterised rain and snow events on Mt. Zugspitze, Germany

    Energy Technology Data Exchange (ETDEWEB)

    Huerkamp, K.; Bernauer, F.; Tschiersch, J. [Helmholtz Zentrum Muenchen (Germany)

    2014-07-01

    Washout of radionuclides by precipitation is regarded to be an efficient deposition process depending on various parameters. Precipitation in the form of snow is suspected to be most efficient in scavenging of aerosol particles. Accidental releases of radionuclides, as seen in the recent nuclear accident of Fukushima-Daiichi in March 2011, have had serious impacts on the terrestrial environment, especially in the mountainous regions where major precipitation has fallen as snow. Supposing that wet deposition depends strongly on the type and characteristics of the precipitation event we present field experiments on the quantification of wet deposition of radionuclides by snow and rain events. The experiments took place in the free atmosphere at the Environmental Research Station Schneefernerhaus on Mt. Zugspitze, Germany (2,650 m a.s.l.). Snowfall event characterisation by meteorological and snow micro-physical parameters was carried out using a 2D video disdrometer combined with a precipitation gauge. Washout of aerosol particles in the size range from 10{sup -2} μm to 10 μm was quantified operating an electrical low pressure cascade impactor ELPI+. Trace analysis was performed by ultra-low level gamma spectrometry (HPGe detectors) of cosmogenic {sup 7}Be, of terrigenic {sup 210}Pb (radon decay product) and of {sup 137}Cs from resuspended fallout of the Chernobyl accident in precipitation and bulk aerosol samples. Dependencies of washout efficiencies of the radionuclides on precipitation rates and snow parameters will be presented. The results shall help to improve radionuclide transport models used in modern decision support systems for emergency management (e.g. ARTM, RODOS), which do not include snow parameters so far. Proposal is made how to incorporate such parameters in future. Document available in abstract form only. (authors)

  16. Recent developments in assessment of long-term radionuclide behavior in the geosphere-biosphere subsystem.

    Science.gov (United States)

    Smith, G M; Smith, K L; Kowe, R; Pérez-Sánchez, D; Thorne, M; Thiry, Y; Read, D; Molinero, J

    2014-05-01

    Decisions on permitting, controlling and monitoring releases of radioactivity into the environment rely on a great variety of factors. Important among these is the prospective assessment of radionuclide behavior in the environment, including migration and accumulation among and within specific environmental media, and the resulting environmental and human health impacts. Models and techniques to undertake such assessments have been developed over several decades based on knowledge of the ecosystems involved, as well as monitoring of previous radionuclide releases to the environment, laboratory experiments and other related research. This paper presents developments in the assessment of radiation doses and related research for some of the key radionuclides identified as of potential significance in the context of releases to the biosphere from disposal facilities for solid radioactive waste. Since releases to the biosphere from disposal facilities involve transfers from the geosphere to the biosphere, an important aspect is the combined effects of surface hydrology, near-surface hydrogeology and chemical gradients on speciation and radionuclide mobility in the zone in which the geosphere and biosphere overlap (herein described as the geosphere-biosphere subsystem). In turn, these aspects of the environment can be modified as a result of environmental change over the thousands of years that have to be considered in radioactive waste disposal safety assessments. Building on the experience from improved understanding of the behavior of the key radionuclides, this paper proceeds to describe development of a generic methodology for representing the processes and environmental changes that are characteristic of the interface between the geosphere and the biosphere. The information that is provided and the methodology that is described are based on international collaborative work implemented through the BIOPROTA forum, www.bioprota.org.

  17. Alternative radionuclides for using in oil exploratory tools - PIG TAG

    Energy Technology Data Exchange (ETDEWEB)

    Pereira Junior, Robson da Costa; Estrada, Julio Jose da Silva, E-mail: jestrada@ime.eb.br [Instituto Militar de Engenharia (IME), Rio de Janeiro, RJ (Brazil); Delgado, Jose Ubiratan; Pinho, Adaugoberto Soares de; Oliveira, Estela Maria de, E-mail: delgado@ird.gov.br, E-mail: soares@ird.gov.br, E-mail: estela@ird.gov.br [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de janeiro, RJ (Brazil)

    2011-07-01

    The ionizing radiations are present from prospecting to production of oil or gas, using a variety of techniques with radioactive sources. The radioactive tracer (pip tag) is a technique in which is placed a mark in different depths of the well that is being profiled. This marker is done generally with gamma emitter {sup 60}Co which activity until 74 kBq (2 {mu}Ci). The purpose of this marker is to identify places of interest of investigations or where will be blast the rock that has been identified as potential hydrocarbon deposits. Currently, these radioactive markers are obtained in the international market in the form of metallic solid sources. However, there are some difficulties in the importation of material, ranging from the permission by the regulatory organization (CNEN) to the customs costs, through the attendance criteria set out in international and national standards related to the transport of radioactive material. These import processes, therefore, involve high costs and delays in having the products. This work aims to develop a methodology that makes possible the preparation of alternative radioactive sources in the country in order to supply the growing demand for this market in a shorter time and with less cost. For this purpose, are being evaluated not only the appropriate support for the markers as well as the possibility of replacement {sup 60}Co by other radionuclides that can perform the same functional properly. This replacement will be based on technical parameters such as energy, half-life, and activity and emission intensity, according to the characteristics of each radionuclide to be evaluated. The production of radioactive markers will be made at the National Laboratory for Metrology of Ionizing Radiation of the Institute of Radioprotection and Dosimetry (IRD), while the field tests had been performed in an industry located in the region of Macae-RJ, which is specialized in marking and profiling of wells oil in deep waters. (author)

  18. Adsorption of Fluoride Ion by Inorganic Cerium Based Adsorbent

    Institute of Scientific and Technical Information of China (English)

    Jiao Zhongzhi(焦中志); Chen Zhonglin; Yang Min; Zhang Yu; Li Guibai

    2004-01-01

    Excess of fluoride in drinking water is harmful to human health, the concentration of F- ions must be maintained in the range of 0.5 to 1.5 mg/L. An inorganic cerium based adsorbent (CTA) is developed on the basis of research of adsorption of fluoride on cerium oxide hydrate. Some adsorption of fluoride by CTA adsorbent experiments were carried out, and results showed that CTA adsorbent has a quick adsorption speed and a large adsorption capacity. Adsorption follows Freundlich isotherm, and low pH value helps fluoride removal. Some physical-chemical characteristics of CTA adsorbent were experimented, fluoride removal mechanism was explored, and results showed that hydroxyl group of CTA adsorbent played an important role in the fluoride removal.

  19. Preparation and Gas Adsorption of Porous Materials from Molecular Precursors

    DEFF Research Database (Denmark)

    Hu, Xinming

    ABSTRACT This thesis deals with the synthesis of porous materials and their applications in gas adsorption. The thesis consists of eight chapters as follows: The first two chapters provide a brief introduction to porous materials and gas adsorption. Chapter 1 gives an overview of construction...... and characteristics of various porous materials, including activated carbons, zeolites, metal-organic frameworks (MOFs), covalent organic frameworks (COFs), and organic porous polymers (POPs). Chapter 2 briefly introduces gas adsorption theory, such as physical and chemical adsorption, adsorption isotherms...... rise to significant red-shift of absorption/emission and reduction of fluorescence lifetime and quantum yield Transition-metal-catalyzed and organolithium-mediated reactions provide polymers with only macroporous interparticle voids and thus very low surface areas (4−51 m2 g−1). Attempts have been also...

  20. Adsorption-Desorption Characteristics of Inorganic Mercury and Methyl Mercury in Soils%无机汞和甲基汞在土壤中的吸附-解吸特性研究

    Institute of Scientific and Technical Information of China (English)

    陈宁; 陈艳; 田超; 司友斌

    2013-01-01

    Adsorption-desorption of inorganic mercury (HgCl2) and Methyl mercury (MeHg) in four different soils and the effects of pH on the adsorption were studied using batch equilibration techniques.The results showed that the adsorption-desorption isotherms of HgCl2 and MeHg in soils were fitted by the Freundlich empirical equation(r>0.98).The adsorption coefficients Kf of HgC