Removal of strontium from simulated low-level radioactive wastewater by nanofiltration

The performance of different nanofiltration (NF) membranes for the treatment of strontium-containing radioactive wastewater was investigated. The effects of the initial strontium concentration, solution pH and complexation phenomena on strontium removal were described. For all the three membranes, the strontium rejection increased with decreasing initial strontium concentration. Meanwhile, the strontium rejection was minimum at the membrane isoelectric point (pH 5) primarily due to decreased co-ion electrostatic repulsion. In the presence of a complexing agent (polyacrylic acid or ethylenediamine tetraacetic acid disodium salt), the strontium rejection was generally higher than those obtained without a complexing agent for NF 270 and XN 45. Membrane cleaning experiments were also conducted to recover the performance of the membranes, which exhibited degradation during long-time filtration. The performance of the membranes after cleaning was close to that of the virgin membranes, especially for XN 45, whose recovery percentage was nearly 100%.

The Effect of Glucose on Saccharomyces cerevisiae Cell Biosorption of Strontium under Simulation Culture Conditions

The effect of glucose on Saccharomyces cerevisiae cell biosorption of strontium under simulation culture conditions was studied in this research. The results showed that the glucose adding did not abviously increase the biosorption efficiency in 30-150 min and after 8 h. The glucose adding might stimulate the S.cerevisiae cell biosorption of strontium ions in 4-8 h for high initial strontium concentration. The results indicated that the glucose adding only stimulated S.cerevisiae cell biosorption of strontium at certain biosorption time and the biosorption process first was a physical adsorption followed bioaccumulation according to interface process and cell growth cycle under simulation culture conditions.