Kinetics and Thermodynamics Study of Thiosulfate Removal from Water by Calcined MgAl-CO_3 Layered Double Hydroxides

摘要

Layered double hydroxides (LDHs) are potential scavengers for anionic contaminants due to their "memory effect". Here we report the removal of thiosulfate anion from contaminated water by calcined MgAl-CO_3 LDH (CLDH). The results indicate that CLDH exhibits a good performance in adsorption of thiosulfate. We studied the kinetics and thermodynamics of adsorption of thiosulfate from water. The equilibrium isotherm showed that the uptake of thiosulfate anion well agrees with the Langmuir equation, the positive value of △H~θ demonstrates the endothermic feature of the adsorption, the pseudo-second order kinetics model can be used to describe the uptake process and the value of Ea was calculated to be 75.898 kJ/mol. Our results suggest that the process of thiosulfate uptaking was controlled by the reaction rate of thiosulfate with the CLDH rather than diffusion.