This work was conducted to determine the practicability of using a new adsorbent 4-ethyl thiosemicarbazide intercalated, organophilic calcined hydrotalcite （ETSC-OHTC） for the removal of uranium （U（Ⅵ））, and tho...This work was conducted to determine the practicability of using a new adsorbent 4-ethyl thiosemicarbazide intercalated, organophilic calcined hydrotalcite （ETSC-OHTC） for the removal of uranium （U（Ⅵ））, and thorium （Th（Ⅳ）） from water and wastewater. The FTIR analysis helped in realizing the involvement of nitrogen and sulphur atoms of ETSC in binding the metal ions through complex formation. Parameters like adsorbent dosage, solution pH, initial metal ions concentration, contact time and ionic strength, that influence adsorption phenomenon, were studied. The optimum pH for maximum adsorption of U（VI） and Th（IV） was found to be in the range 4.0-6.0. The contact time required for reaching equilibrium was 4 hr. The pseudo second-order kinetic model was the best fit to represent the kinetic data. Analysis of the equilibrium adsorption data using Langmuir, Freundlich and Sips models showed that the Freundlich model was well suited to describe the metal ions adsorption. The KF values were 25.43 and 29.11 mg/g for U（Ⅵ） and Th（Ⅳ）, respectively, at 30℃. The adsorbent can be regenerated effectively from U（Ⅵ） and Th（Ⅳ） loaded ones using 0.01 mol/L HC1. The new adsorbent was quite stable for many cycles, without much reduction in its adsorption capacity towards the metals.展开更多
A column chromatographic method has been developed for the separation and determination of cerium(Ⅲ) using poly[dibenzo-18-crown-6].The separation was carried out in L-valine medium.The adsorption of cerium(Ⅲ) was q...A column chromatographic method has been developed for the separation and determination of cerium(Ⅲ) using poly[dibenzo-18-crown-6].The separation was carried out in L-valine medium.The adsorption of cerium(Ⅲ) was quantitative from 1×10-1 to 1×10-4 mol/L L-valine.Amongst the various eluents,1.0-8.0 mol/L hydrochloric acid,1.0-8.0 mol/L hydrobromic acid,1.0-8.0 mol/L perchloric acid,1.0-2.0 mol/L sulfuric acid and 4.0-5.0 mol/L acetic acid,were found to be the efficient eluents for cerium(Ⅲ).The capacity of poly[dibenzo-18-crown-6] for cerium(Ⅲ) was(0.428±0.01) mmol/g.The method was applied to the separation of cerium(Ⅲ) from associated elements link uranium(Ⅵ) and thorium(Ⅳ).It was also applied for the determination of cerium(Ⅲ) in geological samples.The method is simple,rapid and selective with good reproducibility(approximately±2%).展开更多
文摘This work was conducted to determine the practicability of using a new adsorbent 4-ethyl thiosemicarbazide intercalated, organophilic calcined hydrotalcite （ETSC-OHTC） for the removal of uranium （U（Ⅵ））, and thorium （Th（Ⅳ）） from water and wastewater. The FTIR analysis helped in realizing the involvement of nitrogen and sulphur atoms of ETSC in binding the metal ions through complex formation. Parameters like adsorbent dosage, solution pH, initial metal ions concentration, contact time and ionic strength, that influence adsorption phenomenon, were studied. The optimum pH for maximum adsorption of U（VI） and Th（IV） was found to be in the range 4.0-6.0. The contact time required for reaching equilibrium was 4 hr. The pseudo second-order kinetic model was the best fit to represent the kinetic data. Analysis of the equilibrium adsorption data using Langmuir, Freundlich and Sips models showed that the Freundlich model was well suited to describe the metal ions adsorption. The KF values were 25.43 and 29.11 mg/g for U（Ⅵ） and Th（Ⅳ）, respectively, at 30℃. The adsorbent can be regenerated effectively from U（Ⅵ） and Th（Ⅳ） loaded ones using 0.01 mol/L HC1. The new adsorbent was quite stable for many cycles, without much reduction in its adsorption capacity towards the metals.
基金This work was supported by the University Grant Commission for awarding Junior Research Fellowship.
文摘A column chromatographic method has been developed for the separation and determination of cerium(Ⅲ) using poly[dibenzo-18-crown-6].The separation was carried out in L-valine medium.The adsorption of cerium(Ⅲ) was quantitative from 1×10-1 to 1×10-4 mol/L L-valine.Amongst the various eluents,1.0-8.0 mol/L hydrochloric acid,1.0-8.0 mol/L hydrobromic acid,1.0-8.0 mol/L perchloric acid,1.0-2.0 mol/L sulfuric acid and 4.0-5.0 mol/L acetic acid,were found to be the efficient eluents for cerium(Ⅲ).The capacity of poly[dibenzo-18-crown-6] for cerium(Ⅲ) was(0.428±0.01) mmol/g.The method was applied to the separation of cerium(Ⅲ) from associated elements link uranium(Ⅵ) and thorium(Ⅳ).It was also applied for the determination of cerium(Ⅲ) in geological samples.The method is simple,rapid and selective with good reproducibility(approximately±2%).
