Parametric optimization by Box–Behnken design for synthesis of magnetic chitosan-benzil/ZnO/Fe3O4 nanocomposite and textile dye removal

Abstract

In this research work, a new magnetic Schiff's base-chitosan-Benzil/zinc oxide/Fe3O4 nanocomposite (Cs-Bz/ZnO/Fe3O4) was developed to be a promising and recoverable adsorbent for Remazol Brilliant Blue R dye (RBBR) removal from the aquatic environment. Parametric optimization by Box–Behnken design was made to optimize the synthesis condition (loading ZnO nanoparticles into polymeric matrix of Cs) in addition to adsorption operation parameters (adsorbent dose, solution pH, temperature, and contact time). The obtained results show that the fast RBBR removal (98.8%) can be achieved by loading 25% ZnO nanoparticles into polymeric matrix of Cs (Cs-Bz/ZnO-25/Fe3O4), and at optimum adsorption operation parameters (adsorbent dosage of 0.04 g, solution of pH 4, temperature of 60 °C, and contact time of 10 min). At these optimum conditions, the maximum adsorption capacity was found to be 620.5 mg/g. The best isotherm and kinetic models were Freundlich model and pseudo-second-order kinetic model, respectively. The probable RBBR dye adsorption mechanism can be assigned to various types of physicochemical interactions (i.e; electrostatic, n-π, π-π interactions) in addition to hydrogen bonding and Yoshida H-bonding. The output of this research confirms that Cs-Bz/ZnO-25/Fe3O4 is a superior, recoverable, and environment friendly biohybrid nanocomposite adsorbent. The remarkable output of this research can open a window for other possible significant applications such as tenement of real waste water, removal of heavy metal ions, and reduction of chemical oxygen demand.