Influence of parameters on the photocatalytic degradation of phenolic contaminants in wastewater using TiO₂/UV system

The photocatalytic degradation of phenol in aqueous suspension using commercial TiO₂ powder (Degussa P-25) irradiated with UV light was investigated. Photodegradation was compared using a photocatalyst (TiO ₂ alone), direct photolysis (UV alone) and TiO₂/UV in a single batch reactor with mercury lamp irradiation. The study focused on the influence of various operating parameters on phenol treatment efficiency, including catalyst dosage, initial concentration of phenol, temperature, pH and change in pH were systematically investigated. The highest phenol degradation rate was obtained at pH 9.0, temperature 60°C and catalyst dose of 2 μg L^-1 with higher mineralization efficiency (in terms of TOC reduction). Experimental results showed that under optimized conditions the phenol removal efficiency was 98% and 100% for the TiO₂/UV and TiO₂/UV/H₂O₂ system, respectively. No significant effect on addition of chloride and metal ions was observed. Photodegradation of phenol followed first-order kinetics. To test whether the phenol removal was possible for wastewater using a TiO₂/UV system, the degradation study was conducted with the real obtained wastewater. The removal of phenol from obtained wastewater and the synthetic wastewater containing phenol was comparable. The TiO₂/UV system developed here is expected to be useful for the treatment of wastewater containing phenol.