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Wang H.,Xian University of Science and Technology | Wang H.,Huzhou Teachers College | Wu T.,Huzhou Teachers College | Chen J.,Huzhou Environmental Protection Monitoring Center | And 3 more authors.
Journal of Radioanalytical and Nuclear Chemistry | Year: 2014

The sorption behavior of Se(IV) on Fe- and Al-modified bentonite is studied through batch experiments. In order to introduce active centers for Se(IV) sorption, bentonite was modified with iron, iron oxocations and aluminum oxocations at 400, 600 and 800 °C. It was found that calcined temperature had great effect on the sorption with above 80 % sorption at 400 °C, whereas with only 5 % sorption at 800 °C. The sorption capacities for Se(IV) were 112.5 mg/g by FeOH-B, 60.1 mg/g by AlOH-B and 71.9 mg/g by Fe-B, respectively. The pH-dependent and ionic strength-independent Se(IV) sorption on these modified bentonites demonstrated that the sorption mechanism of Se(IV) was inner-sphere surface complexation at low pH values. © 2014 Akadémiai Kiadó, Budapest, Hungary. Source


Wang H.,Xian University of Science and Technology | Wang H.,Huzhou Teachers College | Wu T.,Huzhou Teachers College | Chen J.,Huzhou Environmental Protection Monitoring Center | And 4 more authors.
Journal of Radioanalytical and Nuclear Chemistry | Year: 2014

Humic acid is ubiquitous in soils and water. It affects the migration of radionuclides by complexation or redox reactions. The effect of humic acid on the diffusion of ReO4 - in GMZ bentonite was investigated at dry density from 1,300 to 1,800 kg/m3. The effective diffusion coefficient De and rock capacity factor α were measured by through-diffusion method. The De decreased from 5.5 to 0.59 × 10-11 m2/s and α decreased from 0.2 to 0.12 with the dry density increasing from 1,300 to 1,800 kg/m3. The retardation factor R in GMZ bentonite at three dry densities was obtained, which were less than one. Archie's law was used to describe the relationship between accessible porosity εacc and De. An empirical parameter n (n = 2.2 ± 0.2) was obtained for Re diffusion in GMZ bentonite in the presence of humic acid. © 2014 Akadémiai Kiadó, Budapest, Hungary. Source


Wang H.,University of Science and Technology of China | Wang H.,Huzhou Teachers College | Wu T.,Huzhou Teachers College | Chen J.,Huzhou Environmental Protection Monitoring Center | And 4 more authors.
Journal of Radioanalytical and Nuclear Chemistry | Year: 2015

Humic acid is ubiquitous in soils and water. It affects the migration of radionuclides by complexation or redox reactions. The effect of humic acid on the diffusion of ReO4 − in GMZ bentonite was investigated at dry density from 1,300 to 1,800 kg/m3. The effective diffusion coefficient De and rock capacity factor α were measured by through-diffusion method. The De decreased from 5.5 to 0.59 × 10−11 m2/s and α decreased from 0.2 to 0.12 with the dry density increasing from 1,300 to 1,800 kg/m3. The retardation factor R in GMZ bentonite at three dry densities was obtained, which were less than one. Archie’s law was used to describe the relationship between accessible porosity εacc and De. An empirical parameter n (n = 2.2 ± 0.2) was obtained for Re diffusion in GMZ bentonite in the presence of humic acid. © 2014, Akadémiai Kiadó, Budapest, Hungary. Source


Wang H.,University of Science and Technology of China | Wang H.,Huzhou Teachers College | Wu T.,Huzhou Teachers College | Chen J.,Huzhou Environmental Protection Monitoring Center | And 3 more authors.
Journal of Radioanalytical and Nuclear Chemistry | Year: 2015

The sorption behavior of Se(IV) on Fe- and Al-modified bentonite is studied through batch experiments. In order to introduce active centers for Se(IV) sorption, bentonite was modified with iron, iron oxocations and aluminum oxocations at 400, 600 and 800 °C. It was found that calcined temperature had great effect on the sorption with above 80 % sorption at 400 °C, whereas with only 5 % sorption at 800 °C. The sorption capacities for Se(IV) were 112.5 mg/g by FeOH-B, 60.1 mg/g by AlOH-B and 71.9 mg/g by Fe-B, respectively. The pH-dependent and ionic strength-independent Se(IV) sorption on these modified bentonites demonstrated that the sorption mechanism of Se(IV) was inner-sphere surface complexation at low pH values. © 2014, Akadémiai Kiadó, Budapest, Hungary. Source

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