Use of rice husk as an effective sorbent for the removal of cerium ions from aqueous solution: Kinetic, equilibrium and thermodynamic studies

Abstract

In this research, the sportive removal of cerium ions (Ce (IV) from aqueous solution by rice husk (RH) has been studied in batch mode at ambient temperature. The effect of operational parameters such as contact time, amount of sorbent, initial concentration of metal ion and temperature on the percentage removal of Ce (IV) from aqueous solution was investigated. The Fourier transform infrared spectroscopy, scanning electron microscopy and energy dispersive X-ray analysis techniques were used to confirm the sorption of Ce (IV) onto RH. Kinetics models including pseudo-first-order, pseudo-second-order, Elovich, liquid film diffusion, modified Freundlich equation and Bangham equation were used to study the sorption kinetics. Results showed that the sorption data fitted-well to the pseudo-second-order kinetic model. Experimental data was also subjected to Linear and Nonlinear forms of Langmuir, Freundlich, and Dubinin-Radushkevivh isotherms and attained results exhibited that the sorption data fitted well to nonlinear and linear sorption isotherms. Thermodynamic study indicated that the sorption of Ce (IV) onto RH was an endothermic process and spontaneous in nature. Moreover, the recovery of Ce (IV) and regeneration of sorbent (RH) was carried out by employing various desorbing media.