The untreated bentonite (UB), acid treated bentonite (ATB) and magnetite impregnated bentonite (MIB) has been examined as adsorbents for the removal of Brilliant green (BG) dye from aqueous medium. The batch adsorption experiments were conducted at different pH, contact time, adsorbent dosage, dye concentration and temperature. The adsorption of BG was dependent on pH of the solutions and the optimized pH value for their adsorption is 8. The adsorption data were fitted to Freundlich and Langmuir adsorption models, which were best fitted to Langmuir isotherm model. The monolayer adsorption capacity of UB, ATB and MIB was 689.6, 785, 877 mg/g, respectively. The kinetic study was analyzed by pseudo first, second and intraparticle diffusion models. It was found that adsorption of BG onto all three adsorbents followed pseudo second order kinetic model. The prepared adsorbents were also characterized by scanning electron microscopy (SEM), energy dispersive X-rays (EDX) and XRD.

Mohammad Ishaq, Siraj Sultan, Imtiaz Ahmad, and Khalid Saeed