Sustainable Heavy Metal Removal from Model Aqueous Solutions and Industrial Wastewater Using Softwood Sawdust as Eco-Friendly and Cost-Effective Biosorbent

With increasing global concerns about industrial wastewater treatment and the need for sustainable practices, this study explores the potential of softwood sawdust as an eco-friendly, cost-effective adsorbent for removing heavy metal ions, specifically zinc (Zn2+) and lead (Pb2+), from synthetic model solutions. Factors affecting adsorption include adsorbent particle size, pH, adsorbent dosage, and contact time. A remarkable removal efficiency of 98.2% for Zn2+ and 98.1% for Pb2+ under optimal adsorption conditions of −106 µm average particle size at 8 pH and 0.3 g of adsorbent dosage using 50 (mg/L) initial concentrations for 60 min at ambient temperature. Characterization of the adsorbent used by XRD, FTIR, SEM, and BET analysis confirmed the structural integrity and surface properties of wood sawdust. It is clear that there is a gradual decline in adsorption capacity over multiple reuse cycles due to the depletion of active functional groups. The results confirm wood sawdust’s effectiveness as a locally available, low-cost, and biodegradable option for treating wastewater, eliminating metal ions, supporting environmental conservation, and aligning with sustainability goals.