Papers by Konstantin Volchek
This paper is an overview of pressure-driven membrane processes, both conventional and innovative... more This paper is an overview of pressure-driven membrane processes, both conventional and innovative, that can be used for the removal of arsenic from aqueous streams, such as potable water or effluents. Those processes employ semi-permeable membranes to separate arsenic species from non-hazardous components of the water. Applications of "established" processes, including reverse osmosis, nanofiltration, ultrafiltration, and microfiltration are discussed. However, the main focus of this publication is on a group of new hybrid processes that combine membrane filtration with the enlargement of arsenic-bearing species. This enlargement can be achieved using various mechanisms such as coagulation, adsorption, or ion exchange. The processes are compared in terms of their ability to meet water quality criteria, their technical feasibility, and their overall impact on the environment. The paper reviews results of bench-scale and pilot-scale studies and discusses feasibility of furth...
Journal of Hazardous Materials, 2010
A series of experiments were performed to quantify the adsorption of cesium on ceiling tiles as a... more A series of experiments were performed to quantify the adsorption of cesium on ceiling tiles as a representative of urban construction materials. Adsorption was carried out from solutions to mimic wet environmental conditions. Non-radioactive cesium chloride was used as a surrogate of the radioactive (137)Cs. The experiments were performed in the range of initial cesium concentrations of 0.114-23.9 mg L(-1) at room temperature (21°C) around three weeks. Solution samples were taken after set periods of time and analyzed by inductively coupled plasma mass spectrometry (ICP-MS). The quantity of adsorbed Cs was calculated by mass balance as a function of time. Two kinetic and three equilibrium models were employed to interpret the test results. Determination of kinetic parameters for adsorption was carried out using the first-order reaction model and the intra-particle diffusion model. Adsorption equilibrium was studied using Langmuir, Freundlich and three-parameter Langmuir-Freundlich adsorption isotherm models. A satisfactory correlation between the experimental and the predicted values was observed.
ABSTRACT The effectiveness of decontamination after a chemical, biological or radiological terror... more ABSTRACT The effectiveness of decontamination after a chemical, biological or radiological terrorist attack is determined by the cleanup technologies that are employed. This Chapter describes what is expected from the science community to develop adequate, reliable and economic decontamination methods and equipment. The needs for improved detection methods and adequate personal protection are also discussed.
Journal of Water Chemistry and Technology
A mathematical model is proposed of the phenomenon of the concentration of inorganic ions of low ... more A mathematical model is proposed of the phenomenon of the concentration of inorganic ions of low molecular weight compounds in the transmembrane region. This phenomenon is associated with the appearance of a strong electric field in the diffusional layer, due to the phenomenon of the concentration polarization of the high molecular weight polyelectrolyte that does not pass through the membrane in the case of its high relative concentration. We propose formulas for calculating thelogorithm of the concentration coefficient as a linear function of the filtration rate (pressure).
Metal removal processes based on solid phase extraction or leaching were analyzed. Two aspects we... more Metal removal processes based on solid phase extraction or leaching were analyzed. Two aspects were described: intensification capability of the leaching process combined with membrane separation methods and rinsewaters purification by membranes
Water Science & Technology, 2011
The paper focuses on the evaluation of membrane filtration for the treatment of liquid radioactiv... more The paper focuses on the evaluation of membrane filtration for the treatment of liquid radioactive streams generated in area decontamination operations. In this work, semi-permeable membranes were demonstrated to be effective reducing the volume of wastewater containing cesium and cobalt by two orders of a magnitude. The efficiency of membrane separation was enhanced by employing additives that enlarged the size of target radionuclide species and improved their rejection by the membranes. This was achieved by chelation with synthetic water-soluble polymers and by adsorption on micro particles of adsorbent coupled with micelle formation. The effect of wastewater composition and that of the radionuclide-binding additives on the volume reduction was investigated. Membrane treatment is expected to help simplify further processing and decrease disposal costs.
Journal of hazardous materials, Jan 30, 2011
The adsorption of cesium on cement mortar from aqueous solutions was studied in series of bench-s... more The adsorption of cesium on cement mortar from aqueous solutions was studied in series of bench-scale tests. The effects of cesium concentration, temperature and contact time on process kinetics and equilibrium were evaluated. Experiments were carried out in a range of initial cesium concentrations from 0.0103 to 10.88 mg L(-1) and temperatures from 278 to 313 K using coupons of cement mortar immersed in the solutions. Non-radioactive cesium chloride was used as a surrogate of the radioactive (137)Cs. Solution samples were taken after set periods of time and analyzed by inductively coupled plasma mass spectroscopy. Depending on the initial cesium concentration, its equilibrium concentration in solution ranged from 0.0069 to 8.837 mg L(-1) while the respective surface concentration on coupons varied from 0.0395 to 22.34 μg cm(-2). Equilibrium test results correlated well with the Freundlich isotherm model for the entire test duration. Test results revealed that an increase in tempera...
ABSTRACT The effectiveness of decontamination after a chemical, biological or radiological terror... more ABSTRACT The effectiveness of decontamination after a chemical, biological or radiological terrorist attack is determined by the cleanup technologies that are employed. This Chapter describes what is expected from the science community to develop adequate, reliable and economic decontamination methods and equipment. The needs for improved detection methods and adequate personal protection are also discussed.
ABSTRACT Cited By (since 1996):7, Export Date: 23 September 2013, Source: Scopus
Russian Journal of Applied Chemistry
Journal of Water Chemistry and Technology
We show that it is possible to selectively extract scandium from multicomponent solutions by ultr... more We show that it is possible to selectively extract scandium from multicomponent solutions by ultrafiltration in combination with complexation. The conditions for scandium binding are chosen, and regeneration of polymer complexation is studied. A diagram depicting the ultrafiltration concentration of scandium from mineralizaed groundwaters is presented.
Export Date: 23 September 2013, Source: Scopus
Cited By (since 1996):1, Export Date: 23 September 2013, Source: Scopus
The removal of arsenic, from aqueous liquids by adsorption on alumina, is facilitated by selectin... more The removal of arsenic, from aqueous liquids by adsorption on alumina, is facilitated by selecting the alumina adsorbent to have a particle size below about 200 micrometers, forming a slurry of the alumina and aqueous liquid and agitating the slurry. It has been found that alumina can be selected to have a particle size sufficiently small, or preferably a combination of both particle size sufficiently small and pore size and number sufficiently large, to achieve 50 ppb or less arsenic within about 2 hours treatment. The alumina with adsorbed arsenic is separated from the slurry by steps preferably comprising microfiltration. A precipitation pretreatment can be combined with the slurry treatment e.g. to handle more concentrated solutions.
Advances in Environmental Research
A process has been developed to remove arsenic from contaminated water and wastewater. The effect... more A process has been developed to remove arsenic from contaminated water and wastewater. The effect of initial and operating pH on the uptake of arsenic by two types of activated alumina was investigated in this work. Arsenic concentrations of less than 0.05mg/L were obtained within ten minutes from solutions with initial arsenic levels of greater than 40 mg/L. Lower residual arsenic concentrations were achieved when a constant pH was maintained throughout the experiments. The optimum pH for arsenic emoval was betweenn 2 and 5, with pH 3 resulting in better arsenic removal. The effect of the presence of sulfate on arsenic uptake by alumina was studied. The prsence of sulfate at concentrations higher than 100 mg/L significantly inhibited arsenic adsorption.
The removal of arsenic, from aqueous liquids by adsorption on alumina, is facilitated by selectin... more The removal of arsenic, from aqueous liquids by adsorption on alumina, is facilitated by selecting the alumina adsorbent to have a particle size below about 200 micrometres, forming a slurry of the alumina and aqueous liquid and agitating the slurry. It has been found that alumina can be selected to have a particle size sufficiently small, or preferably a combination of both particle size sufficiently small and pore size and number sufficiently large, to achieve 50 ppb or less arsenic within about 2 hours treatment. The alumina with adsorbed arsenic is separated from the slurry by steps preferably comprising microfiltration. A precipitation pretreatment can be combined with the slurry treatment e.g. to handle more concentrated solutions.
The present invention relates to a process and apparatus to effectively and efficiently remove me... more The present invention relates to a process and apparatus to effectively and efficiently remove metals from contaminated soil wherein a reactor and membrane extraction unit are utilized. The use of the subject system provides improved metal removal from soil over a batch process.
This study focused on the selection and evaluation of sequestering agents which could be used to ... more This study focused on the selection and evaluation of sequestering agents which could be used to improve the radiological decontamination of a commercial chemical/ biological decontamination and blast suppression formulation. More specifically, the work was performed to develop decontamination foam which would be effective for the removal of radioactive contaminants, including cesium, strontium and cobalt from a variety of common urban surface materials. These surfaces might become contaminated as a result of a terrorist attack (e.g. “dirty bomb”) or a radiological accident. Several sequestering agents were selected for this study including polycarboxylic acids, ammonium salts and ferrocyanides. Initially, liquid-phase tests were conducted to determine the relative binding efficiencies of the identified agents towards targeted contaminants. Based on results of these tests, surface decontamination experiments were then conducted using coupons of urban materials spiked with the target...
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Papers by Konstantin Volchek