Sol-gel derived xanthan gum/silica nanocomposite-a highly efficient cationic dyes adsorbent in aqueous system

A sol-gel synthesis of nanocomposite adsorbent materials by dehydroxylation condensation of tetraethoxysilane (TEOS) in the presence of xanthan gum (XG) using base catalyst and ethanol as co-solvent is discussed. The synthesized nanocomposite material was evaluated for their ability to adsorb cationic dyes-methylene blue (MB) and bismarck brown Y (BB) from an aqueous solution. The XG/SiO₂ nanocomposite shows the ordered macro- and meso-porous structures and also exhibited large surface area, excellent chemical/mechanical stability and high binding capability for MB and BB dyes. Different parameters such as pH, adsorbent dose and initial concentration were studied. The adsorption behaviour of the nanocomposite was investigated by performing both kinetics and equilibrium studies under batch conditions. The maximum adsorption capacity (Q_max) of the nanocomposite for MB and BB was found to be significantly high (432.90mgg^-1 and 448.43mgg^-1, respectively). The time taken for the removal of 99.4% of MB and 87.2% of BB from 100mgL^-1 of dye solutions is only 35min. Thus, the proposed XG/SiO₂ nanocomposite is a very promising adsorbent for the fast and efficient removal of dye from aqueous solutions.