Sorption and desorption of radiocobalt on montmorillonite - Effects of pH, ionic strength and fulvic acid

School of Chemical Engineering, Shandong University of Technology, 255049 Zibo, Shandong, PR China.
Applied Radiation and Isotopes (Impact Factor: 1.23). 04/2008; 66(3):288-94. DOI: 10.1016/j.apradiso.2007.07.031
Source: PubMed


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.

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    • "It is physiologically active in the human body only in a definite form, but high consumption of Co causes general poisoning, as well as cardiomyopathy and other diseases (Tomakov et al., 1994). A 60 Co isotope can migrate in the circulation zones of natural surface and subterranean waters, which can come into contact with radioactive waste and land-buried nuclear fuel waste (Chen and Lu, 2008). That is why Co influence on living organisms and biota has been studied intensively in recent years. "

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    • ") satisfy the criteria outlined earlier (Cremers et al., 1988; Avery, 1996; Matishov et al., 1999; Real et al., 2002; Galabov et al., 2003; Khan, 2003; Caron and Mankarios, 2004; Payne et al., 2004; Shinonaga et al., 2005; Whicker and Ibrahim, 2006; Chen and Lu, 2008). Although both radionuclides have previously been used as sediment tracers (e.g. "
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