Photo-degradation of butyl parahydroxybenzoate by using TiO2-supported catalyst.

The present work evaluates the potential of the photocatalysis (PC) process for the degradation of butylparaben (BPB). Relatively high treatment efficiency was achieved by comparison to photochemical process. Prior to photocatalytic degradation, adsorption (AD) of BPB occurred on the titanium dioxide (TiO2)-supported catalyst. AD was described by Langmuir isotherm (KL = 0.085 L g(-1), qm = 4.77 mg g(-1)). The influence of angle of inclination of the reactor, pH, recirculation flow rate and initial concentration of BPB were investigated. The PC process applied under optimal operating conditions (recirculation flow rate of 0.15 L min(-1), angle of inclination of 15°, pH = 7 and 5 mg L(-1) of BPB) is able to oxidize 84.9-96.6% of BPB and to ensure around 38.7% of mineralization. The Langmuir-Hinshelwood kinetic model described well the photocatalytic oxidation of BPB (k = 7.02 mg L(-1) h(-1), K = 0.364 L mg(-1)).