Simultaneous Removal of Cu(II), Cd(II), and Industrial Dye onto a Composite Chitosan Biosorbent

The application of sustainable materials for wastewater treatment can provide a better water quality, by eliminating toxic metals and also organic contaminants. In this study, we demonstrate a simple method to synthesize chitosan/diatomaceous earth composed (CSDE) as an adsorbent for simultaneous adsorption of Amido Black 10B (AB10B), Cd(II), and Cu(II) ions from aqueous solution. The synthesis is based on a surface physical modification of diatomaceous earth by chitosan as a binder. The effects of adsorbent dosage, initial ions concentration, contact time, and pH on the AB10B, Cd(II), and Cu(II) adsorption rate were investigated. Fourier transform infrared spectroscopy confirmed the successful preparation of the CSDE. Under optimal conditions, the adsorption isotherm of AB10B, Cd(II), and Cu(II) onto CSDE fitted the Langmuir model and the adsorption kinetics was well-correlated with the pseudo-second-order model. The CSDE composite exhibited excellent adsorption capacity toward AB10B, Cd(II), and Cu(II) in both single and multicomponent system with removal capacity of 132.8 mg/g—single; 115.3 mg/g—multicomponent (pH 2), 108 mg/g—single; 96.9 mg/g—multicomponent (pH 7), and 97 mg/g—single; 88.27 mg/g—multicomponent (pH 7), respectively, suggesting selective binding capacity and high adsorption efficiency of CSDE composite. The prepared adsorbent could be reused at least ten consecutive adsorption–desorption cycles with marginal decrease in the total adsorption capacity of both metals and AB10B. The prepared adsorbents showed a significant potential for AB10B, Cd(II), and Cu(II) ions recovery in industrial applications.