Silica-based adsorbent material with grape bagasse encapsulated by the sol-gel method for the adsorption of Basic Blue 41 dye

Grape bagasse is an agro-industrial solid waste produced in large quantities representing an environmental issue for wineries. An organic-inorganic hybrid material was obtained by the acid catalyzed sol-gel route in the presence of grape bagasse for application as dye adsorbent. Analysis by FT-IR has shown the main bands related to cellulose, hemicellulose and lignin of the grape bagasse structure and the peaks related to the silica fingerprint region. Zeta potential measurements demonstrated that the hybrid material based on grape bagasse is anionic in a wide range of pH value (2.0-12.0) that favors the adsorption of cationic contaminants. XRD pattern shown amorphous structure that is adequate for adsorption of large molecules as dyes. Then, the effect of pH (3.0-12.0), adsorbent concentration (0.5-5.0 g L-1), and the kinetic of Basic Blue 41 (cationic azo-dye) adsorption onto the hybrid material based on grape bagasse were investigated at various temperatures. The optimal conditions for the dye adsorption were established at pH 6.0 and adsorbent concentration of 5.0 g L-1. The kinetic data were best fitted to the pseudo-second order kinetic model. The maximum monolayer adsorption capacity achieved was 268.1 mg g(-1) at 313K.