The use of TiO2 immobilized into grape marc-based activated carbon for RB-5 Azo dye photocatalytic degradation

Abstract

Titanium dioxide (TiO2) in the mineral form of Anatase has been used as a coating agent by impregnation on powdered grape marc-based activated carbon (GMAC) prepared previously by chemical activation. The prepared material (TiO2/GMAC) acting as a photocatalyst composite was investigated in the removal of reactive black 5 dye (RB5) from aqueous solutions. GMAC and the TiO2/GMAC were characterized by BET surface area, Scanning electron microscopy, DRX and IRTF. Enhancement of the rate of RB5 dye degradation by the composite photocatalyst GMAC/TiO2 compared to the GMAC was observed.Model equations, namely Langmuir, Freundlich and Redlich– Petersen isotherms were used to satisfactorily predict the adsorption of RB5 dye onto the prepared composite. Langmuir–Hinshelwood pseudo first order rate model was applied to the investigation of degradation kinetics. Synergistic effect of the combined material was observed on the surface and inside the pores. COD decrease and, sulfate and nitrate ions release confirm RB5 dye degradation. This novel approach of impregnation process gave the hybrid more homogeneity and stability to better adsorb large molecules such as dyes from industrial effluents. Keywords: Activated carbon, Anatase, Impregnation, Photocatalysis, RB-5 dye, Regeneration