Removal of Pollutants from Wastewater Using Aluminum Oxide Nanoparticles

The use of aluminum oxide nanoparticles (Al-NPs) in wastewater treatment has emerged as a promising approach due to their unique physicochemical properties, including a high surface area, strong adsorption capabilities, and effective adsorbent performance. This study investigates the use of Al-NPs for the removal of chemical oxygen demand (COD) from synthetic aqueous solutions. COD is one of the main indicators of water pollution and can be used to assess water quality. The characterization of Al-NPs was conducted using various techniques, including X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM), Energy Dispersive X-ray (EDX), and the Brunauer-Emmett-Teller (BET) technique. XRD analysis confirmed the successful synthesis of Al-NPs with a well-defined crystalline structure and desirable crystallite size. The data correlated with TEM findings, validating the nanoscale properties of the Al-NPs. The EDX spectrum showed prominent peaks corresponding to aluminum (Al) and oxygen (O), indicating the presence of Al and possibly Al₂O₃. A higher BET surface area typically correlates with improved pollutant adsorption performance, as more surface sites are available for interaction. Adsorption data were analyzed using the Freundlich isotherm model, which suggested a heterogeneous adsorption surface, and the pseudo-second-order kinetic model, indicating that the adsorption mechanism was predominantly chemisorption. These findings highlight the potential of Al-NPs as effective adsorbents for pollutant removal from wastewater, with implications for optimizing treatment processes in industrial and domestic applications. The maximum removal efficiencies (R%) for chemical oxygen demand (COD), phosphate (PO₄), and total suspended solids (TSS) were 97.04%, 42.62%, and 98.63%, respectively. The highest removal efficiency was achieved at an Al-NP dosage of 120 mg/L. These findings demonstrate that Al-NPs can be effectively used as coagulants in wastewater treatment.