Sb(V) removal from copper electrorefining electrolyte: Comparative study by different sorbents

Removal of Sb(V) from copper electrolyte by different sorbents such as activated carbon, bentonite, kaolin, resin, zeolite and white sand was investigated. Adsorption capacity of Sb(V) removal from copper electrolyte was as follows: white sand < anionic resin < zeolite < kaolin < activated carbon < bentonite. Bentonite was characterized using FTIR, XRF, XRD, SEM and BET methods. The results show specific surface area of 95 m2/g and particles size of 175 nm for bentonite. The optimum conditions for the maximum removal of Sb are contact time 10 min, 4 g bentonite and temperature of 40 °C. The adsorption of Sb(V) on bentonite is followed by pseudo-second-order kinetic (R2=0.996 and k=9×10−5 g/(mg·min)). Thermodynamic results reveal that the adsorption of Sb(V) onto bentonite from copper electrolyte is endothermic and spontaneous process (ΔGΘ=-4806 kJ/(mol·K). The adsorption data fit both the Freundlich and Langmuir isotherm models. Bentonite has the maximum adsorption capacity of 10000 mg/g for adsorption of Sb(V) in copper electrolyte. The adsorption of Zn, Co, Cu and Bi that present in the copper electrolyte is very low and insignificant.