Comparative study for the removal of methylene blue via adsorption and photocatalytic degradation

Abstract

Physically and chemically activated carbons were prepared from date pits and olive stones. Titania and WO x -TiO 2/MCM-41 were prepared as photoactive catalysts. Surface characterizations were investigated from ash content, pH, base neutralization capacities and FT-IR techniques. The textural characteristics, namely specific surface area ( S BET ) and pore texture, were determined from low temperature adsorption of N 2 at 77 K. The decolorization of aqueous solution of methylene blue was performed by means of two alternative methods. Steam-activated carbons own higher surface area compared with ZnCl 2-activated carbons, and the micropore surface area represents the major contribution of the total area. Steam-activated carbons were the most efficient decolorizing adsorbents owing to its higher surface area, total pore volume and the basic nature of the surface. The calculated values of Δ G 0 , Δ H 0 and Δ S 0 indicate the spontaneous behavior of adsorption. The photocatalytic degradation is more convenient method in decolorizing of methylene blue compared with the adsorption process onto activated carbons.