Theoretical study and experimental verification of the DMPBP[5] adsorption-enhanced Bi2WO6 photocatalysis Fe3O4 self-Fenton system

In this study, a DMP5 polymer (DMPBP[5]) adsorption enhanced Bi2WO6 (BWO) photocatalysis Fe3O4 self-Fenton system (DMPBP[5]-BWO-Fe3O4) was proposed. The system includes the adsorption of pollutants and active substances by DMPBP[5] as the prerequisite and driving force for the reaction, a Bi-based photocatalyst as an in situ robust H2O2 generator, and decorated Fe3O4 (Fe2+/Fe3+) as the trigger and enhancer for H2O2 formation and transformation, which leads to a highly efficient and stable activity for persistent organic pollutants. Considering the photo-oxidation of RhB as a model reaction, this system exhibits 17–18 times higher photodegradation rate than that of the original BWO, which corresponds to a high catalytic activity of 98.3% (k = 14.2 × 10-3 min−1) within 180 min. The advantages of the system are mainly attributed to: (1) DMPBP[5] has a large specific surface area (1386 m2/g), which provides more adsorption sites for pollutants; (2) Further, through theoretical calculation, we found that the super-strong adsorption capacity of DMPBP[5] for RhB (−0.061 eV) was much higher than that of Fe3O4 (−0.0025 eV) and BWO (−0.0015 eV); (3) The production of H2O2 on DMPBP[5]-BWO-Fe3O4 is greatly increased, and the concentration of H2O2 can be accumulated to 5.506 μM within 120 min, which is about 90.3 times and 9.25 times higher than that of BWO and BWO-D7, respectively. The system presented here provides new insights into the efficient and environmentally friendly removal of refractory organic contaminants.