Photocatalytic treatment of olive mill wastewater using biochar/TiO₂ under sunlight

Olive mill wastewater (OMW), characterized by a high load of recalcitrant organic pollutants, presents a significant environmental burden due to its phytotoxicity and resistance to conventional treatment methods. This study investigates the development and application of a novel biochar-supported titanium dioxide (biochar/TiO₂) photocatalyst for the solar-driven degradation of organic contaminants in OMW. The biochar was synthesized via pyrolysis of palm waste, offering a sustainable support material. The photocatalyst's performance was evaluated with varying TiO₂ contents to determine the optimal composition for maximum pollutant removal efficiency. A composite containing 10% TiO₂ exhibited the highest photocatalytic activity, achieving a 53% reduction in chemical oxygen demand (COD) within the first 10 min and reaching 64% after 240 min of solar exposure. The optimal catalyst loading was determined to be 100 mg, resulting in a 66% COD reduction, with peak efficiency observed at pH 4.5. The findings highlight the potential of the biochar/TiO₂ system as a cost-effective and environmentally sustainable approach for OMW treatment, with promising implications for broader industrial wastewater remediation applications.