Adsorption of Eriochrome Black T from Wastewater Using Activated Carbons Sourced from Agricultural Residues: An In-Depth Review

Synthetic dyes like Eriochrome Black T (EBT) continue to challenge wastewater treatment due to their persistence and toxicity, affecting biodiversity and human health. This expanded review delves into the adsorption of EBT using activated carbons (ACs) and biochars from diverse agricultural residues, incorporating over 50 studies up to 2025. New additions include adsorbents from pepper stalks, jujube cores, pithecellobium seeds, spartium junceum, pinecone powders, poultry feathers, brinjal stalks, ipomoea batatas, dacryodes edulis seeds, and gasified woodchips, alongside established sources like rice hulls and hemp waste. Preparation methods emphasize chemical activation (e.g., H₃PO₄, ZnCl₂) and pyrolysis, yielding surface areas of 200–2500 m²/g and capacities from 4.23 to 369 mg/g. Langmuir isotherms and pseudo-second-order kinetics dominate, with thermodynamics indicating spontaneous, often endothermic processes. Enhanced regeneration (80–95% over 5–7 cycles) and column performance highlight practicality. Interactive visualizations and editable tables facilitate analysis, while discussions on mechanisms, optimization, and scalability address gaps. This work advocates for agro-residue valorization in sustainable remediation, fostering circular economies in dye-laden industries.