Synthesis and application of mesoporous MCM-41 silica with rice husk

Rice husk (RH) is an organic agricultural waste material produced as a byproduct from the rice milling operations. Rice husk is widely used in many industrial applications due to its chemical stability, high mechanical strength, insolubility in water, and its local availability at almost no cost. Untreated and treated rice husks were used in the synthesis of new porous materials such as mesoporous carbons [1], MCM-22 zeolite [2]. Composites of rice husks with MCM-41 and MCM-48 were recently prepared under hydrothermal conditions [3].The plasmonic noble metals (typically gold and silver) have played an important role in the field of photo driven chemical conversion due to their surface plasmon resonance (SPR) [4]. Silver based photocatalysis has been widly investigated for the degradation of environmental pollutants in water fields. More recently, AgBr semiconductor with a direct band gap of 2.5 eV has been used in photocatalytic applications [5].In this study, composite of MCM-41 silica with rice husk (RH/MCM-41) synthesized under hydrothermal conditions and AgBr nanoparticles on RH/MCM-41 loaded. The photocatalytic activity of AgBr-RH/MCM-41 nanocomposite was investigated in Methyl Orange azo dye degradation as a model of pollutant. The prepared nanocomposite were characterized by X-ray diffraction (XRD), diffuse reflactance spectroscopy (DRS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results indicated that the dye solution became completely colourless after the reaction time (105 min) when we used AgBr-RH/MCM-41 as the photocatalyst.