Sorption and desorption of radiocobalt on montmorillonite--effects of pH, ionic strength and fulvic acid.
Humic substances and clay minerals have been studied extensively in radioactive waste management. In our research, the sorption and desorption of radiocobalt on montmorillonite in the presence and absence of fulvic acid as a function of pH and ionic strength were investigated under ambient conditions by using batch techniques. The results indicate that the sorption of cobalt is strongly dependent on pH values and independent of ionic strength. Surface complexation rather than cation exchange is considered as the main mechanism of cobalt sorption to montmorillonite. The presence of fulvic acid enhances cobalt sorption obviously at pH values<8. The desorption behavior changes of surface-sorbed cobalt from montmorillonite were studied by decreasing pH values and the solution cobalt concentrations independently. The results indicated that the sorption of cobalt on montmorillonite is irreversible.
Chen
Lei
L
School of Chemical Engineering, Shandong University of Technology, 255049 Zibo, Shandong, PR China. chenlei761205@sina.com
Lu
Songsheng
S
D000327:Adsorption; D001546:Bentonite / Q000737:chemistry*; D001578:Benzopyrans / Q000737:chemistry*; D003037:Cobalt Radioisotopes / Q000737:chemistry*; D006812:Humic Substances; D006863:Hydrogen-Ion Concentration; D009994:Osmolar Concentration; D011850:Radioactive Waste; D017550:Spectroscopy, Fourier Transform Infrared; D014875:Water Pollutants, Radioactive / Q000737:chemistry*; D014961:X-Ray Diffraction
D001578:Benzopyrans; D003037:Cobalt Radioisotopes; D006812:Humic Substances; D011850:Radioactive Waste; D014875:Water Pollutants, Radioactive; D001546:Bentonite; C005023:fulvic acid