Intensification for the Degradation of Paraphenylenediamine using Hydrodynamic Cavitation Coupled with Advanced Oxidation Processes

Abstract

Paraphenylenediamine (PPD) was used as a pollutant in this study and it was degraded in hydrodynamic cavitation (HC) reactor with an orifice plate and venturi as a cavity generating device, as well as in an ultrasonic cavitation (UC) reactor. The Advance oxidation method (AOP) was used to increase the rate of degradation in this procedure. In AOPs, Hydrogen peroxide and TiO2 as an oxidant and photocatalyst coupled with UV light were used to degrade PPD. To intensify the degradation of PPD, a photocatalyst (TiO2) was synthesised using the sol-gel method and later combined with H2O2 in an HC reactor. The doses of 100 mg/L to 400 mg/L for H2O2 and TiO2 were considered. The highest 71.6% degradation was found at H2O2 of 200 mg/L, more doses than 200 mg/L given almost the same degradation. Using a TiO2 in combination with the optimal H2O2 dose (200 mg/L) and UV light boosted degradation by 77.6%. In HC-O. (HC with orifice). The results showed that HC-O had resulted in the maximum degradation when compared to HC-V (HC with venturi) and UC reactors with and without TiO2 and H2O2. With H2O2 alone, 71.6% degradation was achieved, whereas 52.4 and 55.3% degradation was achieved in HC-V and UC, respectively. At an initial 10 ppm PPD concentration, pH 5, operating temperature (35oC), and H2O2 (200 mg/L), 77.6%, 56.1%, and 67% degradation is achieved in the HC-O, HC-V, and UC reactors with TiO2 (300 mg/L, UV). Hence, AOP is successful with hydrodynamic cavitation reactor for the intensification of PPD under controlled conditions.