Synthesis of Porous Silica Particles for the Adsorption of Organic Dye in Aqueous Medium

Abstract

This study investigated the removal of the organic dye like methylene blue using porous particles in a batch adsorption process. Porous silica microparticles were synthesized with macropores or meso-macropores and used as adsorbent particles. The hierarchically porous structures with additional mesopores were found to be more effective adsorbent than simple macroporous particles. The size of the macropores affected the adsorption capacity of the porous particles, and smaller pore size resulted in a larger amount of organic dye being adsorbed on the particle surface, due to increased surface area. Silica microparticles with wrinkled surfaces were also tested, and their adsorption capacities were studied in relation to their morphologies. Unlike previous studies using mesoporous silica as adsorbents, in this study the methylene blue adsorption kinetics could be explained by the second to fourth order reaction, implying that faster removal of dye molecules is possible compared to photocatalytic reactions, with first order kinetics. The higher order kinetics can be advantageous, providing a faster removal rate, compared to the conventional photocatalytic removal of dyes and other adsorbents.