Reactive dye removal by a novel biochar/ MgO nanocomposite

This research was aimed to synthesize a cost effective charcoal based nano-sorbent and evaluate its adsorption efficiency for the removal of reactive dye blue 221 (RB-221) from synthetic textile waste water. Charcoal was prepared by thermal decomposition of rice straw and a charcoal/MgO nanocomposite was prepared through modified co-precipitation method. The prepared adsorbent was analyzed through X-ray diffraction (XRD), Fourier transform infra-red spectroscopy (FT-IR) and Scanning Electron microscopy (SEM) imaging techniques for its morphology and characterization. XRD analysis showed the crystallite size ranging from 8 to 20 nm. The adsorption efficiency of the nanocomposite was tested through batch experiments. Effects of shaking speed, shaking time, adsorbent dose, pH, temperature and initial adsorbate concentration was studied and optimum conditions were recorded. Langmuir and Freundlich isotherms of adsorption revealed favorable and feasible adsorption of dye on to the charcoal and MgO nanocomposite. Endothermic and spontaneous adsorption was observed through thermodynamic parameters. Data obtained from adsorption studies best fitted pseudo first order kinetic model. The regression factor for this model was calculated to be R/sup 2/= 0.887. The results indicate feasible adsorption of RB-221 on nanocomposite of rice straw charcoal/MgO nanocomposite from aqueous solutions. (author)