Removal of the residual xanthate from flotation plant tailings using modified bentonite

Al-Be was found superior to H-Be in terms of adsorption performance and under optimum conditions (adsorbent dosage: 7500 mg/L; xanthate concentration: 2000 mg/L; pH = 12.2; time = 45 min) and more than 99% of the residual xanthate was removed. The kinetics data were best described by pseudo-second order model for the both adsorbents. The adsorption equilibrium isotherms were fitted by Freundlich, Langmuir, and Temkin models. The isotherm data were best-fitted to the Langmuir model, indicating monolayer adsorption of the xanthate on homogenous surfaces of the both adsorbents. The thermodynamics studies indicated that the adsorption was spontaneous, exothermic with the reducing entropy. The adsorption tests on the real samples taken from the tailing stream of a copper flotation plant (Qaleh-Zari in Iran) proved that both adsorbents are capable of removing more than 90% of the residual xanthate.