We first obtained by impregnating the zeolite with salts U, W and V and examined the X-ray uranium catalyst SAPO-U, W, V based on natural zeolite Chankanayskogoe deposits for the oxidation of SO2 to SO3.
CCl4 （carbon tetrachloride） and n-C6H14 （n-hexane） sorption studies have been carried out on natural and dealuminated clinoptilolite-type zeolites. External surface area of the materials has been assessed using t...CCl4 （carbon tetrachloride） and n-C6H14 （n-hexane） sorption studies have been carried out on natural and dealuminated clinoptilolite-type zeolites. External surface area of the materials has been assessed using the αs-plots method. The high resolution αs-plots show that the isotherms are divided into four parts corresponding to adsorption in ultramicropores, intersections, supermicropores and external surface area, respectively. The mineralogies of natural zeolites are determined by X-ray analysis. N： low-pressure hysteresis loops, displayed by some substrata, are related to the micropore structure and to the ion-exchange treatment at which the natural precursors were subjected. The adsorption behavior of these substrata was examined in the range of relative pressures between 10^-5-1. Natural samples were used as reference materials to carry out the sorption analyses of the dealuminated samples. The effect of narrow micropore constrictions on the adsorption behavior of clinoptilolites was explored. The occurrence of a low-pressure hysteresis loop on the sorption isotherm of a modified sample is associated to the strong adsorption of the adsorbate molecules at the entrance of the necked-shape micropores, which interfere with the diffusion of the adsorbate molecules inside the porous structure.展开更多
The X-ray absorption fine structure(XAFS)technology has exhibited a very unique application in the study of sorption mechanism,chemical species and microstructures of radionuclides at the natural solid-water interface...The X-ray absorption fine structure(XAFS)technology has exhibited a very unique application in the study of sorption mechanism,chemical species and microstructures of radionuclides at the natural solid-water interfaces.In this review,the interaction mechanism of radionuclides with clay minerals and nanomaterials under different environmental conditions are summarized from the XAFS spectroscopy analysis.The coordination number and the bond distances of radionuclides,the oxidation-reduction reactions,the influence of humic substances and microorganisms on the species and structures of radionuclides at molecule level are reviewed and compared.This review is helpful to understand the interactions of radionuclides with oxides,natural clay minerals and nanomaterials,which is also crucial to evaluate the physicochemical behaviors of radionuclides in the natural environment.展开更多
文摘We first obtained by impregnating the zeolite with salts U, W and V and examined the X-ray uranium catalyst SAPO-U, W, V based on natural zeolite Chankanayskogoe deposits for the oxidation of SO2 to SO3.
文摘CCl4 （carbon tetrachloride） and n-C6H14 （n-hexane） sorption studies have been carried out on natural and dealuminated clinoptilolite-type zeolites. External surface area of the materials has been assessed using the αs-plots method. The high resolution αs-plots show that the isotherms are divided into four parts corresponding to adsorption in ultramicropores, intersections, supermicropores and external surface area, respectively. The mineralogies of natural zeolites are determined by X-ray analysis. N： low-pressure hysteresis loops, displayed by some substrata, are related to the micropore structure and to the ion-exchange treatment at which the natural precursors were subjected. The adsorption behavior of these substrata was examined in the range of relative pressures between 10^-5-1. Natural samples were used as reference materials to carry out the sorption analyses of the dealuminated samples. The effect of narrow micropore constrictions on the adsorption behavior of clinoptilolites was explored. The occurrence of a low-pressure hysteresis loop on the sorption isotherm of a modified sample is associated to the strong adsorption of the adsorbate molecules at the entrance of the necked-shape micropores, which interfere with the diffusion of the adsorbate molecules inside the porous structure.
基金supported from the National Natural Science Foundation of China(21225730,91326202,21577032)the Fundamental Research Funds for the Central Universities(JB2015001)+1 种基金the Priority Academic Program Development of Jiangsu Higher Education Institutionsthe Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions
文摘The X-ray absorption fine structure(XAFS)technology has exhibited a very unique application in the study of sorption mechanism,chemical species and microstructures of radionuclides at the natural solid-water interfaces.In this review,the interaction mechanism of radionuclides with clay minerals and nanomaterials under different environmental conditions are summarized from the XAFS spectroscopy analysis.The coordination number and the bond distances of radionuclides,the oxidation-reduction reactions,the influence of humic substances and microorganisms on the species and structures of radionuclides at molecule level are reviewed and compared.This review is helpful to understand the interactions of radionuclides with oxides,natural clay minerals and nanomaterials,which is also crucial to evaluate the physicochemical behaviors of radionuclides in the natural environment.
