Advances in chromium removal using biomass-derived activated carbon: A comprehensive review and bibliometric analysis

This review presents a comprehensive analysis and bibliometric evaluation of chromium (Cr) removal from aqueous solutions using biomass-derived activated carbon. A bibliometric analysis of 250 publications from 2000 to 2024 reveals increasing global research interest, with significant contributions from China, India, and the USA. Key themes identified include adsorption mechanisms, activated carbon modification, and biosorption techniques. Biomass-based adsorbents, such as corn cob, Ulva lactuca, and Eichhornia crassipes, demonstrate high adsorption capacities, ranging from 80 to 250 mg/g for hexavalent chromium (Cr(VI)), depending on preparation methods and operational conditions. The review highlights advanced preparation techniques, including chemical activation with KOH and H₃PO₄, which enhance surface area up to 1500 m² g⁻¹, significantly improving adsorption performance. Despite promising results, challenges persist in scaling up for industrial applications, inconsistent performance across biomass types, and the need for cost-effective regeneration methods. Incorporating nanotechnology, such as metal oxide nanoparticles, has improved removal efficiencies by up to 30%, broadening potential applications. This review provides critical insights into optimizing preparation methods, standardizing operational parameters, and bridging the gap between laboratory findings and real-world applications, underscoring biomass-derived activated carbon as a sustainable and effective solution for chromium-contaminated wastewater treatment.