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Chitosan-clinoptilolite composite was prepared and tested for removing radiocobalt from aqueous solution. The composite was characterized with Fourier transform infrared spectroscopy, X-ray diffraction analysis and scanning electron microscopy coupled with energy dispersive X-ray analysis. The sorption of Co(II) on chitosan-clinoptilolite composite was pH-dependent and ionic strength-independent. The kinetic sorption was fitted well by a pseudo-second-order rate equation. The thermodynamic parameters (Δ H, Δ S, Δ G) revealed that the sorption of Co(II) on chitosan-clinoptilolite composite was spontaneous and endothermic. The study showed that chitosan-clinoptilolite composite had excellent potential for the treatment of wastewater containing radiocobalt. [ABSTRACT FROM AUTHOR]

A synthetic zeolite, commercially available as permutite was tested for removing radiocobalt from aqueous solutions by sorption. The sorption process was studied as a function of contact time, pH, ionic strength and solid content by batch technique. The results revealed that the process is dependent on the pH and ionic strength under ambient conditions. The kinetic sorption was fitted well by a pseudo-second-order rate equation. The thermodynamic parameters (Δ H, Δ S, Δ G) suggested that sorption behavior of Co(II) is a spontaneous and endothermic process. The study shows that permutite has excellent potential for disposal of wastewaters containing radiocobalt. [ABSTRACT FROM AUTHOR]

In this study, the removal of radionuclide Co(II) from wastewater by Ca-rectorite was studied as a function of various environmental parameters such as contact time, pH, ionic strength, coexisting electrolyte ions, humic substances (HS) and temperature under ambient conditions. The results indicated that the sorption of Co(II) on Ca-rectorite was strongly dependent on pH and ionic strength. The Langmuir and Freundlich models were used to simulate the sorption isotherms of Co(II) at three different temperatures of 298.15, 318.15 and 338.15 K. The thermodynamic parameters ( $$ \Updelta H^{0} ,\,\Updelta S^{0} $$ and $$ \Updelta G^{0} $$) calculated from the temperature-dependent sorption isotherms indicated that the sorption process of Co(II) on Ca-rectorite was spontaneous and endothermic. At low pH, the sorption of Co(II) was dominated by outer-sphere surface complexation and ion exchange with Ca/H on Ca-rectorite surfaces, whereas inner-sphere surface complexation was the main sorption mechanism at high pH. From the experimental results, it is possible to conclude that Ca-rectorite has good potentialities for cost-effective disposal of radiocobalt bearing wastewaters. [ABSTRACT FROM AUTHOR]