CLOSED-LOOP METAL RECOVERY: TRANSLATING ADVANCED BIOSORPTION INTO RESOURCE CIRCULARITY

The increasing discharge of metal-contaminated effluents from industrial, mining, electroplating, battery, and electronic sectors has created serious environmental challenges while accelerating the depletion of natural metal resources. Advanced biosorption has emerged as a sustainable and cost-effective technology for the removal and recovery of metals from wastewater using biological materials such as algae, fungi, bacteria, agricultural residues, and engineered biocomposites. This study reviews recent advances in closed-loop metal recovery systems that integrate biosorption with resource circularity and circular economy principles. Key biosorption mechanisms, including ion exchange, chelation, complexation, and electrostatic interactions, are discussed along with strategies for biosorbent regeneration and high-purity metal recovery. Applications in industrial wastewater treatment, acid mine drainage, e-waste leachates, and spent battery recycling demonstrate the potential of biosorption-driven systems for waste valorization and sustainable metal management. Despite challenges related to scale-up, selectivity, and process optimization, advanced biosorption technologies offer a promising pathway toward environmentally friendly metal recovery and resource-efficient industrial development.