PHOTODEGRADATION OF PHENOLIC COMPOUNDS IN TREATED POME USING Mn-MODIFIED DEFECTIVE TiO2 PHOTOCATALYST UNDER VISIBLE LIGHT IRRADIATION

The presence of phenolic compounds in treated palm oil mill effluent (TPOME) is a major human health and environmental concern. The present research aimed to develop an optimized visible-light-driven TiO2 based photocatalytic system for the removal of phenolic compounds from TPOME. Visible-light responsive defective TiO2 was synthesized via glycerol-mediated precipitation method followed by calcination at 300
and 400°C for 1 h. The defective TiO2 was further modified with manganese (Mn) via wet impregnation method. The photocatalytic process was optimized via central composite design (CCD) in response surface methodology (RSM). It was demonstrated that tuning the band structure of TiO2 by inducing Ti3+ defect states play an important role in boasting visible light absorption, promote efficient charge carriers’ separation and suppressing electron-hole pair recombination. Consequently, the improved optical and electronic properties of the defective TiO2 (T2) prepared in 1.163 mol/L glycerol
and calcined at 300°C have led to 48.17% phenolic compounds removal from TPOME which was 2.6-fold higher than P25 (18%).