Ionic chitosan/silica nanocomposite as efficient adsorbent for organic dyes.

A new adsorbent from chitosan and anionic silica was prepared by ionic interaction followed by sol-gel process. The obtained nanocomposite was characterized by different techniques: FTIR, XRD, SEM/EDX, TGA, and TEM. The results showed that silica precursor interacts with chitosan and deposits as regular spherical nanoparticles. The methylene blue (MB) adsorption by chitosan/silica nanocomposite achieved the adsorption equilibrium within 60 min. The adsorption method is fitted to the pseudo-second-order kinetic model and the Langmuir adsorption model with a maximum adsorption capacity of 847.5 mg/g at slight alkaline solution. Chitosan/silica composite displayed high regeneration capability and recovery of MB up to five cycles without the loss of the adsorption efficiency. The current study showed that as-prepared chitosan/silica nanocomposite is an appropriate material for the adsorption of organic pollutants from wastewater.