Synthesis of a novel chitosan-TiO2 nanocomposite as an efficient adsorbent for the removal of methylene blue cationic dye from wastewater

Abstract

This study investigates the efficacy of chitosan-TiO2 nanocomposites (CS-TiO2) as an efficient adsorbent for removing Methylene blue (MB) cationic dye from wastewater. The synthesis of chitosan-TiO2 nanocomposites (CS-TiO2) involved the co-polymerization and crosslinking of Chitosan biopolymer (CS) with titanium dioxide (TiO2). The CS-TiO2 nanocomposites involved their structure, morphology, and characteristics through the utilization of several analytical methods such as FTIR, XRD, SEM, TEM, TGA, UV-visible, DLS, and XPS. The removal of MB dye examined in different concentrations of chitosan exhibits an increase as the pH of the solution increases; the maximum value was attained at pH 6 and 120 minutes of contact time. The optimal dosage of CS-TiO2 nanocomposites for adsorbing methylene blue (MB) was found to be between 0.10 mg/L and 0.20 mg/L. The experimental data was evaluated using the thermodynamic process, Dubinin-Radushkevich, Langmuir, and Freundlich isotherm models. The data were examined using various kinetic models and found to be consistent with pseudo-first order, pseudo-second order, and Intraparticle diffusion kinetics models. Desorption and reuse after adsorption of MB onto CS-TiO2 nanocomposite was investigated using different desorbing agents like NH4OH/NH4Cl or NaOH. These results indicate that CS-TiO2 nanocomposite is a highly effective and cost-effective adsorbent for removing MB dyes from contaminated water.