Advances in the preparation of activated carbon derived from agricultural waste as a sustainable solution for wastewater treatment: A comprehensive review

The main reason of the increasing of hazardous pollutants in aquatic ecosystems, which pose risk to human health and environment, are urbanization and industrialization. Currently, adsorption is widely used, cost effective and environmentally friendly technique for wastewater treatment. Pollutant removal and waste management can be effectively addressed by converting agricultural waste into activated biochar/activated carbon (AC), which serves as sustainable adsorbent for wastewater treatment. Numerous studies are reported on high adsorption capacity activated carbon derived from agricultural waste; however, the evaluation and comparison of these capacities are complicated by difference in precursor dosage, activation techniques, surface modification techniques, structural stability and lifecycle outcomes. In this review, the preparation methods are thoroughly discussed including physical, chemical, microwave assisted, hydrothermal and other advanced modification approaches. Additionally, the review explores the effect of lignocellulosic content on pore formation and surface chemistry. The adsorption behavior of single and multi-pollutant systems is also discussed, highlighting the challenge associated with emerging pollutants such as hydrophilic drugs and short-chain per- and polyfluoroalkyl substances (PFAS). The particular focus is given on elements which impact regeneration of adsorbent, such as attrition loss, mechanical integrity, leeching effects. The review included the application and usage of AI/ML models as emerging and underutilized tool in AC preparation is also discussed. The study summaries the UN Sustainable Development Goals (SDGs) can met by generating AC through effective waste management and pollutant removal. By incorporating preparation of AC, durability concerns, and Lifecycle perspectives, this review attempts to promote the design of scalable adsorbent for wastewater treatment derived from agricultural waste.