Sequential photo-Fenton and sono-photo-Fenton degradation studies of Reactive Black 5 (RB5)

Sequential treatment studies have been done using photo-Fenton and sono-photo-Fenton, and compared with individual processes to analyze possible favorable effects of combined systems for the degradation of Reactive Black 5 (RB5). The coupled system enhances the degradation as compared to the ultrasound or UV–light irradiation processes along with the reduction in treatment time. Batch runs were carried out to investigate the process operational conditions: pH, H2O2 dosage, Fe2+ dosage, and RB5 concentration; to obtain the results at best possible operating conditions render advanced oxidation processe (AOP) competitive with other processes; and to ensure the rapid and complete transformation of the toxic organic compounds to benign chemicals. Degradation observed was 69% under Fenton and 93% under photo-Fenton with experimentally optimized conditions i.e. pH 4, Fe2+ concentration 0.050 gL−1 and H2O2 0.150 gL−1 after 20 min. Sono-photo-Fenton treatment enhances the degradation up to 98% with experimentally optimized parameters within 12 min of reaction.