OIL REMOVAL FROM WASTEWATER USING BIOMASS-DERIVED ACTIVATED CARBON-A SYSTEMATIC REVIEW OF SYNTHESIS, PERFORMANCE, AND MECHANISMS

Abstract

Oil-contaminated wastewater poses serious environmental and health risks, creating a need for sustainable and effective treatment technologies. This systematic review evaluates the performance of biomass-derived activated carbon for oil and organic contaminant removal, focusing on synthesis, adsorption mechanisms, regeneration, and scale-up. Following the PRISMA framework, 1,240 Scopus records were screened, and 64 studies published between 2023 and 2025 were included. The reviewed literature shows that biomass-derived activated carbon can achieve removal efficiencies above 90% under controlled laboratory conditions. Chemical activation using KOH, H₃PO₄, or ZnCl₂ generally produces high surface area and well-developed porosity. However, adsorption performance is also influenced by pore-size distribution, surface chemistry, hydrophobicity, pH, adsorbent dosage, contaminant concentration, and contact time. Adsorption commonly follows pseudo-second-order kinetics and the Langmuir isotherm, involving pore filling, van der Waals forces, hydrophobic interactions, electrostatic attraction, hydrogen bonding, π–π interactions, and chemisorption. Major limitations include reduced performance in real wastewater, capacity loss during regeneration, and limited pilot-scale evidence. Future research should prioritize continuous-flow validation, low-energy regeneration, techno-economic assessment, and life-cycle analysis.

Keywords: biomass-derived activated carbon, oily wastewater, oil removal, adsorption, regeneration, industrial scale-up.