Factors affecting the sorption behavior of Cs+ and Sr2+ using biosorbent material

Abstract

In this study, saw dust has been used as precursor for production of low cost activated carbon using potassium hydroxide (KOH) and steam activation technique. The activated carbon was used to remove Cs⁺ and Sr²⁺ ions from aqueous solutions by batch operation, and the extent of adsorption was investigated as a function of solution pH, temperature, shaking time, and initial concentration. The influence of interfering ions was also investigated. The removal of metal ions was pH dependent and the adsorption capacity reaches its maximum 43% and 61.5% at pH 5.0 and 6.0 for Cs⁺ and Sr²⁺ ions, respectively. Thermodynamic studies showed different behaviours where an endothermic, non-spontaneous process was shown for Cs⁺ while an exothermic, spontaneous process was obtained for Sr²⁺. The kinetic data of both ions was described well by pseudo-second order rate equation. The two equilibrium models (Langmuir and Freundlich) have been also applied. Desorption studies indicated that HCl was the most effective desorbing eluent. The investigated adsorbent showed good results towards cesium and strontium removal from aqueous media that could be a promising method due to its low-cost and good efficiency.