Removal of crystal violet from wastewater by activated carbons prepared from rice husk

Adsorption onto activated carbons is a potent method for the treatment of dye-bearing effluents because it offers various advantages. In this study, activated carbons, prepared by a new technique from low-cost rice husk by sulfuric acid and zinc chloride activation, were used as the adsorbent for the removal of crystal violet, a basic dye, from aqueous solutions. The effects of various experimental parameters, such as adsorbent dosage and size, initial dye concentration, pH, contact time, and temperature, were investigated in batch mode. The kinetic data were well fitted to the Lagergren, pseudo-second-order, and intraparticle diffusion models. It was found that intraparticle diffusion plays a significant role in the adsorption mechanism. The isothermal data could be well described by the Langmuir and Freundlich equations. The maximum uptakes of crystal violet by sulfuric acid activated (RHS) and zinc chloride activated (RHZ) rice husk carbon were found to be 64.875 and 61.575 mg/g of adsorbent, respectively. The results indicate that RHS and RHZ could be employed as low-cost alternatives to commercial activated carbon in wastewater treatment for the removal of basic dyes.