Temperature Dependence Of Sorption Research Articles

Sorption of PAHs to microplastic and their bioavailability and toxicity to marine copepods under co-exposure conditions

Organic chemical pollutants associated with microplastic (MP) may represent an alternative exposure route for these chemicals to marine biota. However, the bioavailability of MP-sorbed organic pollutants under conditions where co-exposure occurs from the same compounds dissolved in the water phase has rarely been studied experimentally, especially where pollutant concentrations in the two phases are well characterized. Importantly, higher concentrations of organic pollutants on ingested MP may be less bioavailable to aquatic organisms than the same chemicals present in dissolved form in the surrounding water. In the current study, the sorption kinetics of two model polycyclic aromatic hydrocarbons (PAHs; fluoranthene and phenanthrene) to MP particles in natural seawater at 10 and 20 °C were studied and the bioavailability of MP-sorbed PAHs to marine copepods investigated. Polyethylene (PE) and polystyrene (PS) microbeads with mean diameters ranging from 10 to 200 μm were used to identify the role of MP polymer type and size on sorption mechanisms. Additionally, temperature dependence of sorption was investigated. Results indicated that adsorption dominated at lower temperatures and for smaller MP (10 μm), while absorption was the prevailing process for larger MP (100 μm). Monolayer sorption dominated at lower PAH concentrations, while multilayer sorption dominated at higher concentrations. PE particles representing ingestible (10 μm) and non-ingestible (100 μm) MP for the marine copepod species Acartia tonsa and Calanus finmarchicus were used to investigate the availability and toxicity of MP-sorbed PAHs. Studies were conducted under co-exposure conditions where the PAHs were also present in the dissolved phase (Cfree), thereby representing more environmentally relevant exposure scenarios. Cfree reduction through MP sorption was reflected in a corresponding reduction of lethality and bioaccumulation, with no difference observed between ingestible and non-ingestible MP. This indicates that only free dissolved PAHs are significantly bioavailable to copepods under co-exposure conditions with MP-sorbed PAHs.

Chemical compatibility of PU/PAN interpenetrating polymer network membrane with substituted aromatic solvents

Polyethylene glycol (PEG)-based polyurethane/polyacrylonitrile (PU/PAN, 50/50) semi-interpenetrating polymer network (SIPN) membrane has been studied from sorption/desorption cycles and diffusion behaviour with substituted aromatic probe molecules at 20, 40 and 60 °C. Sorption/desorption cycles have been repeated to evaluate polymer–solvent interaction. Organic solvents taken up or given out by IPN are measured periodically till equilibrium. Using these data, sorption ( S), diffusion ( D) and permeation ( P) coefficients have been calculated from Fick's equation. Sorption data is correlated with solubility parameter of solvents and polymer. It was found that solvents of comparable solubility parameter with IPN interact more and thus there is an increase in sorption. Molecular mass between cross-link has been calculated using Flory Rehner equation. The cross-link density and degree of cross-linking of the membrane is calculated. From the temperature dependence of sorption and diffusion coefficients, the Arrhenius activation parameters like activation energy for diffusion ( E D ) and permeation ( E P ) processes have been calculated. Furthermore, the sorption results have been interpreted in terms of thermodynamic parameters such as change in enthalpy (Δ H) and entropy (Δ S). Concentration profiles of penetrants at different penetration depths in the polymer sample at different time intervals have also been calculated theoretically from a solution of Fick's equation under appropriate initial boundary conditions.

Np(V)O2+sorption on hydroxyapatite-effect of calcium and phosphate anions

The sorption of NpO2+from aqueous solution on hydroxyapatite was studied as a function of the amount of sorbent, initial NpO2+concentration, ionic strength and pcH. The hydroxyapatite was characterized by SEM, EDS, XRD, FT-IR and ICP-MS measurements. At ionic strengths of 0.10 to 5.00 M NaClO4, the sorption increased with increased pcH to a maximum between pcH 8−8.5, then decreased as the pcH increased.The kinetics of NpO2+sorption on hydroxyapatite followed Lagergren first order kinetics. The temperature dependence of sorption was small in the range of 273−283 K, but increased more sharply at higher temperatures of 298−333 K. The heat of sorption of NpO2+was endothermic and the free energy values were exothermic indicating large, positive entropy. The activation energy for the sorption process was calculated to be 29.52±1.2 kJ/mole. The effect of calcium and phosphate on NpO2+sorption was studied as a function of concentration and pcH.

Uptake of Metal Ions on Humic Acids

The kinetics, the sorption capacities, pH and temperature dependence of sorption of humic acids (HAs) of Turkish brown coals with respect to Zn(II), Cu(II), Ni(II), Co(II) and Pb(II) ions were investigated, and the roles of the carboxylic and phenolic groups in the adsorption of metals ion on HAs were searched in this work. These metal ions are able to form complex compounds with carboxylic and phenolic groups of HAs. Adsorption equilibrium was achieved in between 50 and 60 min for all studied cations. HAs extracted from different brown coals have been characterized by chemical and physical methods. The chemical properties of HAs showed differences depending on the source from which they were obtained. The sorption of metals on the surface of HAs depends strongly on the pH, and sorption decreases with decreasing pH. Maximum removal of metal ions was demonstrated at pH values of 4.1–5.0. The Langmuir adsorption isotherm was used to describe observed sorption phenomena. The Δ G 0 became negative as the temperature increased, and so the equilibrium constant decreased slightly. The investigation proved that the HAs are suitable materials for the studied heavy metal ion removal from aqueous solution and could be considered as potential material for purification of effluent polluted with toxic metal ions.

Chemical Compatibility Testing of Linear Low Desnity Polyethylene Geomembrane

Chemical compatibility testing of linear low density polyethylene geomembrane (LLDPE) has been studied from a measurement of sorption/ desorption and diffusion for 14 organic liquids at 25, 50 and 70°C. Sorption results are obtained by a gravimetric method and diffusion coefficients have been calculated from Fick's equation for the initial linear data points of the time-dependent sorption/desorption curves. Permeability coefficients have been calculated from the diffusion and sorption values. Swelling was studied by measuring the increase in thickness, diameter and thereby calculating the volume dilation of the geomembrane. From the temperature dependence of sorption and diffusion coefficients, the Arrhenius activation parameters have been calculated. Liquid concentration profiles have also been calculated theoretically from a solution of the Fick's equation under appropriate initial and boundary conditions. Results of this study are discussed to find the possible application of the LLDPE for a specific hazardous site involving exposure to the chosen liquids.

Molecular migration of low sorbing organic liquids into polymeric geomembranes

Laboratory test results of sorption/desorption for tetrahydrofuran, tetralin, 1,4-dioxan, methyl acetate, ethyl acetate and butyl acetate into high density polyethylene, linear low density polyethylene, very low density polyethylene and polypropylene geomembranes at 25, 50 and 70 °C are presented. Partition coefficients are calculated from the measured increase in the mass of geomembranes immersed in the liquid of interest, from the initial value until the mass becomes constant. From the initial linear portions of the sorption curves, the diffusion coefficients of liquids into the geomembranes are calculated using the Fick equation. From a temperature dependence of sorption, diffusion and permeation coefficients, the Arrhenius parameters are calculated for each of these processes. Results of the preliminary findings reported here might be useful in the applications of geomembranes in containment facilities. © 1999 Society of Chemical Industry

Sorption/desorption, diffusion, and swelling characteristics of geomembranes in the presence of halo-organic liquids

Sorption/desorption results of halogen-containing liquids into high-density polyethylene, linear low-density polyethylene, very low-density polyethylene, and polypropylene geomembranes are presented at 25, 50, and 70°C. Sorption results are obtained by a gravimetric method, and diffusion coefficients have been calculated by using Fick's equation from the initial linear portions of the sorption/desorption curves. Swelling of the geomembranes was studied from a measurement of the increase in volume, thickness, and diameter. From a temperature dependence of sorption and diffusion coefficients, the Arrhenius parameters have been calculated. Liquid concentration profiles have been computed using Fick's equation for the appropriate initial and boundary conditions. The results of this study may have relevance in selecting the suitable geomembrane for a specific application in hazardous waste chemical ponds and other similar situations.

Sorption/desorption, diffusion, permeation and swelling of high density polyethylene geomembrane in the presence of hazardous organic liquids

The laboratory findings on sorption and desorption of 14 organic liquids into high density polyethylene (HDPE) geomembranes are presented at 25, 50 and 70°C. The values of diffusion and permeation coefficients have been calculated using these data. Swelling of the HDPE geomembrane was studied by monitoring its increase in thickness and diameter and thereby calculating the increase in volume. From a temperature dependence of sorption, diffusion and permeation coefficients, the Arrhenius parameters have been calculated. From the sorption data, the concentration profiles of liquids inside the HDPE by solving Fick's diffusion equation under the appropriate initial and boundary conditions. Results of this research may have relevance in the application of HDPE geomembrane in the hazardous waste environment containing the solvents used in this research.

Chemical compatibility testing of geomembranes – sorption/desorption, diffusion, permeation and swelling phenomena

The laboratory test results of 14 organic liquids (widely varying in nature) for high density polyethylene, linear low density polyethylene, very low density polyethylene and polypropylene geomembranes are presented at 25, 50 and 70°C. The partition coefficients have been calculated by monitoring the increase in mass of geomembrane immersed in the fluid of interest from its initial value until the mass of geomembrane becomes constant. From such data, diffusion and permeation coefficients have been calculated using Fick’s equation from the initial linear portions of the sorption curves. Swelling of the geomembranes has also been studied from a measurement of an increase in volume, thickness and diameter. From a temperature dependence of sorption, diffusion and permeation coefficients, the Arrhenius parameters have been calculated.

Chemical compatibility study of geomembranes—sorption/desorption, diffusion and swelling phenomena

Sorption/desorption results of n-alkanes into high density polyethylene, linear low density polyethylene, very low density polyethylene and polypropylene geomembranes are presented at 25, 50 and 70°C. Sorption results are obtained by a gravimetric method and diffusion coefficients have been calculated by using Fick's equation from the initial linear portions of the sorption/desorption curves. Swelling of the geomembranes was studied from a measurement of the increase in volume, thickness and diameter. From a temperature dependence of sorption and diffusion coefficients, the Arrhenius parameters have been calculated. Liquid concentration profiles have been computed using Fick's equation for the appropriate initial and boundary conditions. The results of this study may have relevance in selecting the suitable geomembrane for a specific application in hazardous waste chemical ponds and other similar situations.

Chemical Resistivity of Very Low Density Polyethylene Geomembranes - Sorption/Desorption, Diffusion and Swelling

The chemical resistivity testing of very low density polyethylene (VLDPE) geomembranes is important in view of their applications in hazardous waste sites. We present here some useful experimental data on the sorption, desorption, diffusion and swelling of VLDPE with 14 organic liquids at 25, 50 and 70°C. Sorption results were obtained by a gravimetric method, and diffusion coefficients have been calculated using Fick's equation from the initial linear portions of the sorption/desorption curves. Swelling was studied by the measurement of increases in volume, thickness and diameter of the VLDPE geomembrane. The Arrhenius activation parameters have been calculated from the temperature dependence of sorption and diffusion coefficients. Liquid concentration profiles were also calculated from Fick's equation under appropriate initial and boundary conditions. The results of this study may be useful for the application of VLDPE geomembranes in hazardous waste chemical ponds.

Chemical Resistivity of Very Low Density Polyethylene Geomembranes - Sorption/Desorption, Diffusion and Swelling

The chemical resistivity testing of very low density polyethylene (VLDPE) geomembranes is important in view of their applications in hazardous waste sites. We present here some useful experimental data on the sorption, desorption, diffusion and swelling of VLDPE with 14 organic liquids at 25, 50 and 70°C. Sorption results were obtained by a gravimetric method, and diffusion coefficients have been calculated using Fick's equation from the initial linear portions of the sorption/desorption curves. Swelling was studied by the measurement of increases in volume, thickness and diameter of the VLDPE geomembrane. The Arrhenius activation parameters have been calculated from the temperature dependence of sorption and diffusion coefficients. Liquid concentration profiles were also calculated from Fick's equation under appropriate initial and boundary conditions. The results of this study may be useful for the application of VLDPE geomembranes in hazardous waste chemical ponds.

An assessment of chemical compatibility of bromobutyl rubber, chlorosulfonated polyethylene and epichlorohydrin membranes in the presence of some hazardous organic liquids

The present study addresses the currently available polymeric materials which are possibly used as liner materials in waste chemical ponds against hazardous organic liquids. To assess the chemical compatibility, bromobutyl rubber (BIIR), chlorosulfonated polyethylene and epichlorohydrin (ECO) are selected for exposure to chloroalkanes and non-chlorinated liquids. These solvents come under the category of hazardous liquids and protection from their contamination to ground water and other aquatics is an important hygienic requirement. One of the possible means of studying the chemical compatibility of the liner membranes against such liquids is to investigate their transport characteristics into the membrane matrices. Thus, results of sorption and diffusion of the above-mentioned systems in the temperature interval 25–60 °C are presented using the sorption gravimetric technique. These results are analyzed by using the Fickian equation. The dependence of transport coefficients on the size and shape of the liquid molecules is discussed. Transport results are greatly influenced by the type of the polymer-solvent interactions in addition to the size of the liquid molecules. The Arrhenius activation parameters are estimated from a temperature dependence of sorption, diffusion and permeation coefficients. Enthalpy and entropy of sorption for the polymer-solvent systems have also been studied. Computed parameters and experimental results are used to discuss the transport mechanism in terms of the type and nature of the polymer membranes and the solvent molecules. Volume dilation of the polymers in the presence of the chosen liquid media has been measured. BIIR and ECO membranes appeared to be reactive toward tetrahydrofuran at 60 °C.

An assessment of chemical compatibility of bromobutyl rubber, chlorosulfonated polyethylene and epichlorohydrin membranes in the presence of some hazardous organic liquids

The present study addresses the currently available polymeric materials which are possibly used as liner materials in waste chemical ponds against hazardous organic liquids. To assess the chemical compatibility, bromobutyl rubber (BIIR), chlorosulfonated polyethylene and epichlorohydrin (ECO) are selected for exposure to chloroalkanes and non-chlorinated liquids. These solvents come under the category of hazardous liquids and protection from their contamination to ground water and other aquatics is an important hygienic requirement. One of the possible means of studying the chemical compatibility of the liner membranes against such liquids is to investigate their transport characteristics into the membrane matrices. Thus, results of sorption and diffusion of the above-mentioned systems in the temperature interval 25–60 °C are presented using the sorption gravimetric technique. These results are analyzed by using the Fickian equation. The dependence of transport coefficients on the size and shape of the liquid molecules is discussed. Transport results are greatly influenced by the type of the polymer-solvent interactions in addition to the size of the liquid molecules. The Arrhenius activation parameters are estimated from a temperature dependence of sorption, diffusion and permeation coefficients. Enthalpy and entropy of sorption for the polymer-solvent systems have also been studied. Computed parameters and experimental results are used to discuss the transport mechanism in terms of the type and nature of the polymer membranes and the solvent molecules. Volume dilation of the polymers in the presence of the chosen liquid media has been measured. BIIR and ECO membranes appeared to be reactive toward tetrahydrofuran at 60 °C.

Diffusion and sorption of organic liquids through polymer membranes. VIII. Elastomers versus monocyclic aromatic liquids

AbstractSorption and diffusion of five monocyclic aromatic liquids—three halogenated benzenes, nitrobenzene, and aniline—with five engineering polymers—ethylene propylene diene ter‐polymer, nitrile butadiene rubber, styrene butadiene rubber, natural rubber, and neoprene—have been investigated in the temperature interval of 25–60°C. Solvent diffusivity into polymer membranes was determined from the immersion/weight gain experiments. Permeability coefficients were also calculated from the diffusion and sorption data. A temperature dependence of sorption and transport was also investigated to estimate the activation parameters. The experimental results and computed quantities were used to study the type of transport mechanism and the nature of polymer‐solvent interactions.

Diffusion and Sorption of Organic Liquids Through Polymer Membranes. IX. Bromobutyl Rubber, Chlorosulfonated Polyethylene, and Epichlorohydrin Versus Substituted Monocyclic Aromatic Liquids

Abstract Sorption and diffusion of four monocyclic aromatic liquids—namely, chlorobenzene, o-dichlorobenzene, bromobenzene, and nitrobenzene into bromobutyl rubber, chlorosulfonated polyethylene, and epichlorohydrin—have been investigated in the temperature interval of 25–60°C by using a gravimetric technique. The transport results have been analyzed by using the Fickian model of diffusion. The dependence of transport coefficients on the size and shape of the penetrant molecules has been discussed. Transport coefficients have not shown any systematic variation with the penetrant size, but the results are greatly influenced by the polymer-solvent interactions. The Arrhenius activation parameters have been estimated from a temperature dependence of sorption, diffusion, and permeation coefficients. The first-order kinetic rate constants have been obtained from the time-dependent sorption data. Enthalpy and entropy of sorption for the polymer-solvent systems have been studied. The molar mass between network c...

Sorption of144Ce(III) and147Pm(III) on hydrated iron sesquioxide

The sorption of144Ce(III) and of147Pm(III) on hydrated iron sesquioxide suspension and the sorption of144Ce(III) on hydrated iron sesquioxide in a laboratory column were studied. The dependence of the sorption on pH and time, the sorption isotherm, the temperature-dependence of sorption, and the effects of ionic strength on sorption and desorption were determined under static conditions. The maximum sorptions of144Ce(III) and147Pm(III) were reached at pH=7.4 (Kd=8.9·105) and pH=9.1 (Kd=6.2·105), respectively.