Removal of cobalt, strontium and cesium from radioactive laundry wastewater by ammonium molybdophosphate-polyacrylonitrile (AMP-PAN)

Applicability of ammonium molybdophosphate-polyacrylonitrile (AMP-PAN) on the adsorptive removal of Co, Sr and Cs in the radioactive laundry wastewater generated from nuclear power plants was investigated. Single- and bi-solute competitive adsorptions of Co2+, Sr2+ and Cs+ onto AMP-PAN were investigated. The influencing factors such as co-existing metal ion and surfactants were investigated. Adsorption of Co2+, Sr2+ and Cs+ onto AMP-PAN occurs via both physical adsorption due to weak van der Waals forces and ion exchange of ammonium molybdophosphate. The results of adsorption model analyses showed that AMP-PAN has high selectivity for Cs+. The maximum adsorption capacities were 0.16, 0.18 and 0.61 mmol/g for Co2+, Sr2+ and Cs+, respectively. In bi-solute competitive adsorptions, adsorption of one metal ion was suppressed by the presence of competing metal ion. Alkali metal (Na+) inhibits adsorption of Cs+ and the presence of Ca2+ ion decreased the adsorption of Co2+ onto AMP-PAN. Adsorption behaviors of Co2+, Sr2+ and Cs+ onto AMP-PAN in the presence of surfactants were quiet different. The presence of cationic (OTMA and HDTMA) and anionic surfactants (SDBS and SOBS) decreased adsorption of Co2+, Sr2+ and Cs+ onto AMP-PAN, but that of non-ionic surfactants (Tween 80 and Triton X-100) did not. (C) 2010 Elsevier B.V. All rights reserved.