Affiliation: School of Chemical Engineering, Universiti Sains Malaysia, Engineering Campus, 14300 Nibong Tebal, Pulau Pinang, Malaysia.
Degussa P25 powder embedded and TiO2 immobilized on activated carbon (TiO2-P25/AC) was used for photocatalytic degradation of phenol. The effects of TiO2-P25 loading, solution pH and initial phenol concentration were investigated using response surface methodology (RSM) based on central composite design (CCD). By applying the quadratic regression analysis, the polynomial expression describing the process efficiency as simultaneous functions of the selected independent variables was developed. Accordingly, the optimum condition was found as follows: TiO2-P25 loading=2 layers, solution pH=5 and initial phenol concentration=25 mg/L. Degradation efficiency of phenol of at least 99.1% was obtained experimentally under such optimal conditions, which was highly agreed with that 98.9% estimated by the equations.