Study on Enhancing Adsorption Efficiency in Best Available Techniques for Arsenic Reduction in Water

The Integrated Environmental Management System promotes the treatment of emissions, wastewater, and waste using Best Available Techniques (BAT), accounting for environmental, economic, and technical factors. Heavy metals in wastewater, including arsenic, a highly toxic and carcinogenic substance, have raised significant global water quality concerns. Adsorption technology for arsenic removal is favored due to low installation and operational costs and its stability across water quality variations. While magnesium oxide-based adsorbents are actively researched, conventional methods often require surfactants, making large-scale production costly. This study developed a porous, layered magnesium oxide adsorbent by calcining a precursor of magnesium ions and ethylene glycol. The adsorbent showed strong affinity for pentavalent arsenic ions, and structural and adsorption mechanisms were analyzed. SEM analysis revealed surface characteristics, and BET analysis showed a specific surface area of 34.98 m²/g. Kinetic experiments (0-12 hours) applied pseudo-first and pseudo-second-order models, and adsorption isotherms, tested for initial concentrations of 10-1000 mg/L, were fitted to Langmuir and Freundlich models with a qmax of 817.8 mg/g. Results indicated that the pseudo-second-order (R²=0.881) and Freundlich models (R²=0.968) best fit the data, suggesting physical, multilayer adsorption. Higher initial pH improved performance, and FT-IR and XPS analysis compared the adsorbent before and after adsorption.