Highly efficient adsorption of eosin yellow dye from aqueous solutions using polymer-based nanocomposite developed from cross-linked chitosan-citrate and Co2O3 nanoparticles

Abstract

The utilization of polymer-based nanocomposites offers a particularly interesting method for removing organic dyes from waterways. This study aimed to efficient removal of eosin yellow (EOY) dye from aqueous solutions using polymer-based nanocomposite (hereinafter, CHA-CIT/Co2O3 NPs) prepared from crosslinked chitosan-citrate (CHA-CIT) and Co2O3 nanoparticles (Co2O3 NPs). The CHA-CIT/Co2O3 NPs adsorbent was investigated by several approaches like XRD, BET analysis, FTIR spectroscopy, FESEM-EDX, and pHpzc analysis, to get a thorough understanding of its structural and chemical characteristics. Box-Behnken design (BBD) was adopted to systematically optimize crucial adsorption parameters, including CHA-CIT/Co2O3 NPs dose (0.01–0.07 g), starting solution pH (4–10), and contact duration (10–40 min). The CHA-CIT/Co2O3 NPs nanocomposite's BET surface area was found to be 19.85 m2/g. The mean pore diameter was determined to be 4.3 nm, and the total pore volume was measured to be 0.0213 cm3/g. The average crystallite size of 23.22 nm is indicative of the CHA-CIT/Co2O3 NPs nanocomposite's mainly polycrystalline characteristics. The kinetic investigations showed an agreement with the pseudo-first-order model, while the equilibrium results agreed well with the Freundlich isotherm model, suggesting the presence of multilayer adsorption behavior. The adsorption capacity of CHA-CIT/Co2O3 NPs for EOY was found to be 650.03 mg/g at a temperature of 25 °C, highlighting its exceptional adsorption ability. The work introduces a novel and efficient chitosan nanocomposite as a potential adsorbent for the high-performance removal of organic dyes from water-based solutions.