Sustainable water treatment using agricultural residue Adsorbents: Evaluating Efficacy and life cycle impacts

Abstract

This study evaluated an agricultural residue-derived adsorbent (ARA), optimized at a pyrolysis temperature of 840 °C, for its adsorption efficiency, water treatment potential and environmental sustainability. The ARA featured a large surface area (520 m²/g), well-developed micro/mesopores, and functionalized surfaces, enabling rapid and effective removal of organic water contaminants through π–π electron donor–acceptor interactions. Its adsorption performance with a Q_max of 6.17 mg/g against humic acid, was comparable to that of widely used commercial activated carbons (ACs). Life cycle assessment, based on adsorption capacity as the functional unit, revealed ARA’s superior environmental profile with a 22 % less global warming potential compared to conventional coal-based AC. The ARA demonstrated carbon–neutral and eco-friendly properties across ten TRACI impact categories, which includes acidification, eutrophication, ecotoxicity, fossil fuel depletion and human health risks. Sensitivity analysis identified activation processes and electricity consumption as critical contributors to environmental impacts, emphasizing the importance of optimizing production processes and incorporating renewable energy sources. These findings highlight ARA’s potential as a sustainable, green alternative to fossil-fuel-derived adsorbents. Beyond its high adsorption performance, the material aligns with global efforts to reduce the environmental footprint of water treatment technologies, and the results of this study support a paradigm shift toward integrating operational efficiency and environmental sustainability into adsorbent design.