Adsorption of Copper (II) from Real Textile Wastewater Using Natural and Waste Materials

Heavy metals are major toxic anthropogenic contaminants released into the environment mainly through wastewater discharges. Adsorption is one of the most effective and widely applied methods for their removal from aqueous systems. However, although activated carbon is commonly used, its high cost and limited regenerability motivate the search for cheaper and more environmentally friendly alternatives. In this study, selected natural and waste-derived materials were evaluated for Cu2+ removal from both model solutions and atypical textile wastewater. Coffee grounds, chestnut seeds, acorns, potato peels, eggshells, marine shells, and poultry bones were tested and compared with commercial activated carbon. Their structural and functional properties were characterised using specific surface area measurements, optical microscopy, SEM-EDS, and FTIR analyses. Two adsorption isotherm models (Langmuir and Freundlich) were used to analyse the experimental data for the selected adsorbents, and model parameters were determined by linear regression. Based on model solution tests, two materials showed the highest Cu2+ sorption potential: coarse poultry bones (97.0% at 24 h) and fine cockle shells (96.2% at 24 h). When applied to real textile wastewater, the bone-derived material achieved the highest Cu2+ removal efficiency (79.4%). Although this efficiency is lower than typical values obtained in laboratory solutions, it demonstrates the feasibility of waste-derived materials as low-cost adsorbents and suggests that further optimisation could further improve their performance.