Advances in adsorbent materials for heavy metals remediation: a roadmap for sustainability

The pervasive presence of heavy metal contaminants in the environment has become a pressing ecological and public health concern due to their toxicity, persistence, and bioaccumulative behavior. Heavy metals, primarily introduced through anthropogenic activities, disrupt natural ecosystems and threaten human health. This review examines recent advancements in adsorbent materials for heavy metal remediation with an emphasis on sustainability, commercial viability, and enhanced performance metrics. Emerging classes of adsorbents, such as biochar, two-dimensional (2D) materials, agricultural waste-derived adsorbents, and metal-organic frameworks (MOFs), have been highlighted for their high removal efficiencies (> 90% removal efficiency in several studies), reusability, and cost-effectiveness. This review also explores innovative synthesis strategies, including green methods and nanostructuring, which enable the fine-tuning of adsorbent properties for practical, real-world applications. In addition, value-added pathways for spent adsorbents, such as their reuse in energy production and construction materials, are discussed. By incorporating lifecycle assessment, performance benchmarking, and scalability considerations, this review provides a comprehensive framework for the development of next-generation adsorbents that are scientifically robust, economically feasible, and aligned with global sustainability and circular economy objectives.