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The sorption of thorium, protacintium and plutonium onto silica particles in the presence of a colloidal third phaseRoberts, Kimberly Ann 15 May 2009 (has links)
The fate of actinides in the environment is of interest for a several
reasons. In oceanic surface waters actinides such as thorium and protactinium,
and in particular their ratio, are used as tracers of processes such as boundary
scavenging and paleocirculation. Thorium is also used to estimate residence
times and particle and colloid fluxes from the euphotic zone, which is useful in
global carbon budgets used to assess effects of global warming. Terrestrially,
contaminated areas in need of remediation, such as former nuclear weapons
production facilities, remain as repositories for no longer needed actinide
stockpiles or waste by-products such as plutonium. All three of these actinides:
thorium, protactinium, and plutonium are known to be particle-reactive but the
extent to which they sorb to immobile particles and mobile colloids can vary
with environmental conditions. Understanding controls on adsorption is
important in understanding uses and any limitations of these radioactive tracers
caused by colloids.
Often laboratory studies to understand actinide behavior are conducted
at concentrations (micro- to millimolar), which are orders of magnitude higher than they are found in the environment (femto- to picomolar). Colloids, a size
class of particles operationally defined as 1 nm to 1 µm in size, are ubiquitous in
aquatic systems. The effect colloids have on actinide particle association, i.e.
competitive or enhancing, can have a profound influence on the ultimate
behavior of the actinide.
The overall aim of this study is to assess sorption of thorium,
protactinium and plutonium onto silica particles as a proxy for inorganic
particles found in surface or ocean waters. In addition to the binary system of
actinide/silica, the ternary system actinide/ organic colloid/ silica were also
carried out to determine the affect of the organic colloid has on particle
association. In particular, extracellular polymeric substances (EPS) extracted
from laboratory grown bacteria and phytoplankton cultures were utilized as
they too are ubiquitous in aquatic systems and have shown to strongly complex
actinide ions, with EPS involved in oceanic scavenging of Th, as well as
immobilization/mobilization of Pu in contaminated areas on land.
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Multi-Hydrid Sorptionsanlage zur kombinierten Heizung und KühlungWillers, Eike. January 2002 (has links)
Stuttgart, Univ., Diss., 2002.
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Sorption and transport of heterocyclic aromatic compounds in soilsBi, Erping, January 2006 (has links)
Tübingen, Univ., Diss., 2006.
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The Mechanics Involved in Removing Copper Ions Using Hydrochars, Activated Carbons, and ResinsHobson, John T 06 December 2019 (has links)
According to the World Health Organization around 785 million people do not have a good source for their drinking water. [1] The lack of clean water comes from a lack of access to proper water treatment methods, and the presence of heavy metals in rivers and coastal areas, due in a large part, to industrial run-off. Sorption techniques that use different materials including hydrochars, activated carbons, and resins can be used to clear heavy metals and organic compounds from water. Biomass is a cost effective supply due to its large abundance and when carbonized, yields chars that can be used as adsorbents. Hydrothermal carbonization (HTC) is the process where biomass is converted to hydrochar. In this work, hydrochars were compared to traditional adsorbents for the removal of copper ions in a copper nitrate solution. Incorporating acids such as acrylic acid and vinyl sulfonic acid into the HTC process was done to see how adding an acid affects the performance of the hydrochars ability to remove copper ions. These hydrochars were then activated with a base solution, which improved the hydrochar’s ability to remove copper ions. Lastly, FTIR and titration of sorption materials was done to understand how adsorption of copper ions is related to the material’s acid concentration. The results showed that hydrochars exhibit a strong intensity of carboxylic acids on their surface. In addition, activation helped to ionize the hydrochars’ acid sites to give the char a more negatively charged surface to adsorb the positively charged copper ions. Overall, activated hydrochars have adsorption capacities that are comparable to traditional adsorption materials and that there is promise in exploring these materials as adsorbents in wastewater treatment.
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Influences on the sorption affinity of soil organic matter for non-ionic organic pollutants.Ahangar, Ahmad G. January 2009 (has links)
Sorption of non-ionic organic compounds to organic matter is usually characterized as a partitioning interaction, which is quantified by K [subscript]oc, the organic-C normalized partitioning coefficient. However K [subscript]oc for any single compound varies considerably between soils, often by a factor of 3-10. This study addresses some of the potential causes of this variability. Forty-four soil cores were collected from a 2 ha paddock. Ten of these cores were selected for sorption measurements. The chemical composition of the soil organic matter (SOM) was determined using ¹³C NMR analysis. It was found that K [subscript]oc for diuron was positively correlated with aryl C (r² = 0.59) and negatively correlated with O-alkyl C (r² = 0.84). There were no such correlations for phenanthrene K [subscript]oc. A second set of experiments was carried out to investigate the effects of SOM– mineral interactions on the sorption properties of a selection of the soils. It was found that HF-treatment increased K [subscript]oc for both phenanthrene and diuron. The HF treatment removes mineral matter leaving the organic phase unaffected by the treatment. The increase in K [subscript]oc on HF-treatment soils provides strong evidence that interactions between organic matter and soil minerals block organic matter sorption sites. Furthermore, following HF-treatment, there was a positive correlation between K [subscript]oc for phenanthrene and aryl C and carbonyl C and a negative correlation with O-alkyl C. This suggests that the non-constancy of the relationship between organic matter chemistry and K [subscript]oc, for whole soils in the case of phenanthrene, may be a consequence of variability of the effect of organic matter-mineral interactions on K [subscript]oc. The influence of lipids on the sorption of diuron and phenanthrene to soils was also investigated. Lipids are known to cover the surfaces of organic matter in soil. K [subscript]oc for diuron and phenanthrene were consistently higher for the lipid-extracted soils than for the whole soils (average of 31% for diuron and 29% for phenanthrene), indicating that lipids block sorption sites on the organic matter. Sorption experiments on one pair of HF-treated soils indicated that the blocking effects of minerals and lipids are independent, because lipid extraction and HF-treatment combined increased K [subscript]oc by more than either treatment alone. In the last experiment, the effect of solvent conditioning on the sorption of diuron and phenanthrene was investigated. The K [subscript]oc values for compounds were consistently higher for solvent-treated whole soil and lipid-extracted soil than corresponding soils before solvent treatment. Solid-state ¹³C NMR spectra of the solvent-treated soils indicated that there were no significant changes in the chemical structure of SOM caused by solvent treatment. Solvent treatment changes the physical conformation of the SOM, increasing its sorption affinity. The key findings from the research are: • Variations in sorption affinity for diuron are related to differences in the soil organic matter chemistry. • SOM-mineral interactions can have a substantial influence on K [subscript]oc for non- ionic compounds. • Lipids may block the active sorption sites on the SOM thereby diminishing sorption overall. • Solvent conditioning can change the physical conformation of SOM and lead to enhancement sorption of diuron and phenanthrene. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1372068 / Thesis (Ph.D.) - University of Adelaide, School of Earth and Environmental Sciences, 2009
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Influences on the sorption affinity of soil organic matter for non-ionic organic pollutants.Ahangar, Ahmad G. January 2009 (has links)
Sorption of non-ionic organic compounds to organic matter is usually characterized as a partitioning interaction, which is quantified by K [subscript]oc, the organic-C normalized partitioning coefficient. However K [subscript]oc for any single compound varies considerably between soils, often by a factor of 3-10. This study addresses some of the potential causes of this variability. Forty-four soil cores were collected from a 2 ha paddock. Ten of these cores were selected for sorption measurements. The chemical composition of the soil organic matter (SOM) was determined using ¹³C NMR analysis. It was found that K [subscript]oc for diuron was positively correlated with aryl C (r² = 0.59) and negatively correlated with O-alkyl C (r² = 0.84). There were no such correlations for phenanthrene K [subscript]oc. A second set of experiments was carried out to investigate the effects of SOM– mineral interactions on the sorption properties of a selection of the soils. It was found that HF-treatment increased K [subscript]oc for both phenanthrene and diuron. The HF treatment removes mineral matter leaving the organic phase unaffected by the treatment. The increase in K [subscript]oc on HF-treatment soils provides strong evidence that interactions between organic matter and soil minerals block organic matter sorption sites. Furthermore, following HF-treatment, there was a positive correlation between K [subscript]oc for phenanthrene and aryl C and carbonyl C and a negative correlation with O-alkyl C. This suggests that the non-constancy of the relationship between organic matter chemistry and K [subscript]oc, for whole soils in the case of phenanthrene, may be a consequence of variability of the effect of organic matter-mineral interactions on K [subscript]oc. The influence of lipids on the sorption of diuron and phenanthrene to soils was also investigated. Lipids are known to cover the surfaces of organic matter in soil. K [subscript]oc for diuron and phenanthrene were consistently higher for the lipid-extracted soils than for the whole soils (average of 31% for diuron and 29% for phenanthrene), indicating that lipids block sorption sites on the organic matter. Sorption experiments on one pair of HF-treated soils indicated that the blocking effects of minerals and lipids are independent, because lipid extraction and HF-treatment combined increased K [subscript]oc by more than either treatment alone. In the last experiment, the effect of solvent conditioning on the sorption of diuron and phenanthrene was investigated. The K [subscript]oc values for compounds were consistently higher for solvent-treated whole soil and lipid-extracted soil than corresponding soils before solvent treatment. Solid-state ¹³C NMR spectra of the solvent-treated soils indicated that there were no significant changes in the chemical structure of SOM caused by solvent treatment. Solvent treatment changes the physical conformation of the SOM, increasing its sorption affinity. The key findings from the research are: • Variations in sorption affinity for diuron are related to differences in the soil organic matter chemistry. • SOM-mineral interactions can have a substantial influence on K [subscript]oc for non- ionic compounds. • Lipids may block the active sorption sites on the SOM thereby diminishing sorption overall. • Solvent conditioning can change the physical conformation of SOM and lead to enhancement sorption of diuron and phenanthrene. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1372068 / Thesis (Ph.D.) - University of Adelaide, School of Earth and Environmental Sciences, 2009
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Influences on the sorption affinity of soil organic matter for non-ionic organic pollutants.Ahangar, Ahmad G. January 2009 (has links)
Sorption of non-ionic organic compounds to organic matter is usually characterized as a partitioning interaction, which is quantified by K [subscript]oc, the organic-C normalized partitioning coefficient. However K [subscript]oc for any single compound varies considerably between soils, often by a factor of 3-10. This study addresses some of the potential causes of this variability. Forty-four soil cores were collected from a 2 ha paddock. Ten of these cores were selected for sorption measurements. The chemical composition of the soil organic matter (SOM) was determined using ¹³C NMR analysis. It was found that K [subscript]oc for diuron was positively correlated with aryl C (r² = 0.59) and negatively correlated with O-alkyl C (r² = 0.84). There were no such correlations for phenanthrene K [subscript]oc. A second set of experiments was carried out to investigate the effects of SOM– mineral interactions on the sorption properties of a selection of the soils. It was found that HF-treatment increased K [subscript]oc for both phenanthrene and diuron. The HF treatment removes mineral matter leaving the organic phase unaffected by the treatment. The increase in K [subscript]oc on HF-treatment soils provides strong evidence that interactions between organic matter and soil minerals block organic matter sorption sites. Furthermore, following HF-treatment, there was a positive correlation between K [subscript]oc for phenanthrene and aryl C and carbonyl C and a negative correlation with O-alkyl C. This suggests that the non-constancy of the relationship between organic matter chemistry and K [subscript]oc, for whole soils in the case of phenanthrene, may be a consequence of variability of the effect of organic matter-mineral interactions on K [subscript]oc. The influence of lipids on the sorption of diuron and phenanthrene to soils was also investigated. Lipids are known to cover the surfaces of organic matter in soil. K [subscript]oc for diuron and phenanthrene were consistently higher for the lipid-extracted soils than for the whole soils (average of 31% for diuron and 29% for phenanthrene), indicating that lipids block sorption sites on the organic matter. Sorption experiments on one pair of HF-treated soils indicated that the blocking effects of minerals and lipids are independent, because lipid extraction and HF-treatment combined increased K [subscript]oc by more than either treatment alone. In the last experiment, the effect of solvent conditioning on the sorption of diuron and phenanthrene was investigated. The K [subscript]oc values for compounds were consistently higher for solvent-treated whole soil and lipid-extracted soil than corresponding soils before solvent treatment. Solid-state ¹³C NMR spectra of the solvent-treated soils indicated that there were no significant changes in the chemical structure of SOM caused by solvent treatment. Solvent treatment changes the physical conformation of the SOM, increasing its sorption affinity. The key findings from the research are: • Variations in sorption affinity for diuron are related to differences in the soil organic matter chemistry. • SOM-mineral interactions can have a substantial influence on K [subscript]oc for non- ionic compounds. • Lipids may block the active sorption sites on the SOM thereby diminishing sorption overall. • Solvent conditioning can change the physical conformation of SOM and lead to enhancement sorption of diuron and phenanthrene. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1372068 / Thesis (Ph.D.) - University of Adelaide, School of Earth and Environmental Sciences, 2009
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Influences on the sorption affinity of soil organic matter for non-ionic organic pollutants.Ahangar, Ahmad G. January 2009 (has links)
Sorption of non-ionic organic compounds to organic matter is usually characterized as a partitioning interaction, which is quantified by K [subscript]oc, the organic-C normalized partitioning coefficient. However K [subscript]oc for any single compound varies considerably between soils, often by a factor of 3-10. This study addresses some of the potential causes of this variability. Forty-four soil cores were collected from a 2 ha paddock. Ten of these cores were selected for sorption measurements. The chemical composition of the soil organic matter (SOM) was determined using ¹³C NMR analysis. It was found that K [subscript]oc for diuron was positively correlated with aryl C (r² = 0.59) and negatively correlated with O-alkyl C (r² = 0.84). There were no such correlations for phenanthrene K [subscript]oc. A second set of experiments was carried out to investigate the effects of SOM– mineral interactions on the sorption properties of a selection of the soils. It was found that HF-treatment increased K [subscript]oc for both phenanthrene and diuron. The HF treatment removes mineral matter leaving the organic phase unaffected by the treatment. The increase in K [subscript]oc on HF-treatment soils provides strong evidence that interactions between organic matter and soil minerals block organic matter sorption sites. Furthermore, following HF-treatment, there was a positive correlation between K [subscript]oc for phenanthrene and aryl C and carbonyl C and a negative correlation with O-alkyl C. This suggests that the non-constancy of the relationship between organic matter chemistry and K [subscript]oc, for whole soils in the case of phenanthrene, may be a consequence of variability of the effect of organic matter-mineral interactions on K [subscript]oc. The influence of lipids on the sorption of diuron and phenanthrene to soils was also investigated. Lipids are known to cover the surfaces of organic matter in soil. K [subscript]oc for diuron and phenanthrene were consistently higher for the lipid-extracted soils than for the whole soils (average of 31% for diuron and 29% for phenanthrene), indicating that lipids block sorption sites on the organic matter. Sorption experiments on one pair of HF-treated soils indicated that the blocking effects of minerals and lipids are independent, because lipid extraction and HF-treatment combined increased K [subscript]oc by more than either treatment alone. In the last experiment, the effect of solvent conditioning on the sorption of diuron and phenanthrene was investigated. The K [subscript]oc values for compounds were consistently higher for solvent-treated whole soil and lipid-extracted soil than corresponding soils before solvent treatment. Solid-state ¹³C NMR spectra of the solvent-treated soils indicated that there were no significant changes in the chemical structure of SOM caused by solvent treatment. Solvent treatment changes the physical conformation of the SOM, increasing its sorption affinity. The key findings from the research are: • Variations in sorption affinity for diuron are related to differences in the soil organic matter chemistry. • SOM-mineral interactions can have a substantial influence on K [subscript]oc for non- ionic compounds. • Lipids may block the active sorption sites on the SOM thereby diminishing sorption overall. • Solvent conditioning can change the physical conformation of SOM and lead to enhancement sorption of diuron and phenanthrene. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1372068 / Thesis (Ph.D.) - University of Adelaide, School of Earth and Environmental Sciences, 2009
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Some sorption and salt occlusion properties of silicalite-1Flynn, Tracey Karen January 1987 (has links)
No description available.
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The influence of temperature on the fate and transport of phthlates in indoor environmentsBi, Chenyang 11 September 2014 (has links)
Phthalate esters are extensively used as plasticizers in building materials and consumer products, but are associated with serious health concerns. They are ubiquitous indoors, redistributing from their original source to all interior surfaces, including airborne particles, dust, and skin. The main objective of the research is to investigate the influence of temperature on the fate and transport of phthalates in indoor environments. In this study, the concentrations of benzyl butyl phthalate (BBzP) and di-2-ethylhexyl phthalate (DEHP) in indoor air, settled dust, and on different interior surfaces including mirror, glass, plate, cloth and wood were measured periodically in a test house. The measurements were conducted at temperatures of 21°C and 30°C, respectively. In addition, sorption kinetics was also monitored at the temperature of 21°C. The air concentrations of BBzP and DEHP at 21°C range from 141 ng/m₃ to 210 ng/m₃ and 66 ng/ m₃ to 100 ng/ m₃, respectively. For impervious surfaces such as dish plates, the surface concentrations reached steady-state concentrations in less than 24 hours, to the level between 2 and 8 [mu]g/m₂ for both BBzP and DEHP. In contrast, the time to reach steady state was much longer for porous surfaces such as hardwood (>1 week) and dust (> months). With the temperature increase to 30°C, the gas phase concentrations of BBzP and DEHP increased by about five times, and the surface concentrations on various surfaces also increased correspondingly. This investigation suggests that temperature has an important influence on the fate and transport of phthalates in indoor environments. / text
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