Modification of Rice straw via Polyelectrolyte Layer-by-Layer Assembly for high performance Dye adsorption

Dyes released from industrial textile processing constitute major problems into the environment. Rice straw is one of agricultural plant wastes in Egypt affects the public health. In the present work, layer by layer self-assembly of Polydiallyldimethylammonium chloride (PDADMAC)/ poly lignin sulphonat (PLS) was designed on the surface of rice straw (RS) in the presence and absence of nano-SiO 2. Removal of anionic dyes from aqueous solutions by the modified rice straw (MRS) was investigated. The adsorption experiments were carried out as function of MRS dosage, contact time and dye type. The results showed that the presence of nano-SiO 2 between the multilayers decreases the resistance of the boundary layer surrounding the adsorbent and increased markedly the efficiency of color removal by accelerating the adsorption process. Zeta potential indicates the existence of positive-charge functional groups in the framework of MRS. The amount of adsorbed dyes was greatly influenced by molecular structure of the dyes. The highest color removal percentage was approximately 95%, provided strong evidence of the potential of MRS for the technological applications of anionic dyes removal from aqueous solutions.