A flow-circulation reactor for simultaneous photocatalytic degradation of ammonia and phenol using N-doped ZnO beads

Abstract In this study, a novel continuous flow-circulation photocatalytic reactor was acquired for treatment of synthetic wastewater containing a binary mixture of ammonia and phenol. Performance of the photo-reactor was examined using synthesized N-Doped ZnO Beads (N-ZnB) within the existence of Hydrogen peroxide (H2O2) and UV irradiation. The Beads of catalyst were synthesized using modified sol–gel method. A protocol was followed for the characterization of N-ZnB catalyst by performing some common analytical methods such as SEM, EDS, Raman and DRS. N-Doping narrows in band gap energy as calculated from DRS the band gab energy reduced from 3.2 eV to 3.16 eV and reduces electron – hole pair recombination and accordingly improves the efficiency of ammonia and phenol photo-degradation. The optimum photo-degradation conditions were detected by examining the effect of operational parameters as the flow rate, pH, catalyst dosage, H2O2 concentration and initial concentration for both ammonia and phenol. At optimum conditions, N-ZnB catalyst achieved 98.3% and 95.8% degradation for both ammonia and phenol, respectively, after 2 hr of UV irradiation. Also, the reusing ability and strength of N-ZnB was investigated. The developed beads could be used as an effective catalyst for the degradation of binary mixture of ammonia and phenol from wastewater.