Novel CdS/MIL-88A heterojunction coupled with H2O2/air-nanobubbles for enhanced visible-light driven photocatalytic performance

Recently, nanobubble (NB) technology has gained much attention due to its special merits. The generation of reactive species enables it to address wastewater treatment and disinfection issues. In this research, for the first time, the combination of a heterojunction with NB and hydrogen peroxide (H2O2) for enhanced dye photodegradation was developed. Characteristics of CdS/MIL-88A photocatalyst were examined by XRD, SEM/EDX, TEM, FT-IR, UV–Vis-DRS, PL, and BET techniques. The influence of NB/H2O2 on photodegradation of direct blue 71 dye (DB 71) was systematically investigated by varying pH, H2O2 concentration, catalyst dosage, and DB 71 concentration. Results showed that DB 71 photodegradation was significantly improved by H2O2/NB assist due to high mass transfer and high generation rate of reactive species. About 99% of DB 71 (70 mg/L) were decomposed by CdS/MIL-88A/H2O2/NB system for 80 min of reaction time at ambient conditions. The DB 71 degradation process was best described by pseudo-1st-order kinetics model with R2 > 0.918 for all cases. CdS/MIL-88A photocatalyst was effectively recycled by using simple and environmental friendly process which permitted a DB 71 removal yield of over 78% after five regeneration cycles. The CdS/MIL-88A/H2O2/NB system generated both HO• and O2•- radicals responsible for degrading DB 71. © 2022