Chitosan-Based Adsorption for Heavy Metal Removal in Electroplating Wastewater: A Sustainable and Cost-Effective Approach

Abstract

Electroplating wastewater contains significant concentrations of toxic heavy metals including copper (Cu), zinc (Zn), nickel (Ni), and iron (Fe), which pose severe environmental and public health risks when discharged without adequate treatment. Conventional treatment technologies such as chemical precipitation, membrane filtration, ion exchange, and electrochemical methods, while effective, are often associated with high operational costs, secondary pollution, and excessive energy consumption. Chitosan, a biopolymer derived from the deacetylation of chitin found abundantly in crustacean shells, has emerged as a promising, sustainable, and cost-effective adsorbent for heavy metal removal from aqueous solutions. This review comprehensively examines the application of chitosan-based adsorbents for the removal of Cu(II), Zn(II), Ni(II), and Fe(II/III) from electroplating wastewater. The production process of chitosan from arthropod and mollusc sources was discussed, along with detailed characterization techniques including Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), Scanning Electron Microscopy with Energy Dispersive X-ray Spectroscopy (SEM-EDS), Thermogravimetric Analysis (TGA), X-ray Fluorescence (XRF), and textural property analysis. The adsorption mechanisms, including complexation, electrostatic attraction, and ion exchange, are critically evaluated. Furthermore, the influence of environmental factors such as pH, temperature, contact time, adsorbent dosage, and initial metal concentration on chitosan adsorption performance is assessed.