Bromine functionalized Fe/Cu bimetallic MOFs for accelerating Fe(III)/Fe(II) cycle and efficient degradation of phenol in Fenton-like system

Abstract

Fe–based metal–organic frameworks (Fe–MOFs) have been widely used in heterogeneous Fenton-like processes. However, the catalytic performance of Fe-MOFs is limited by the relatively slow Fe (III)/Fe (II) redox cycle. For Fe-MOFs, increasing the interfacial electron transfer and reducing the electron density of Fe-MOFs are expected to accelerate the reduction of Fe (III) and improve the catalytic performance. Here, by mixing Fe/Cu metal species and introducing bromine groups, we successfully prepared bromine-functionalized bimetallic MOFs–FeCu(BDC-Br), and we used it to effectively degrade phenol in a Fenton-like process. Compared with most other catalysts, FeCu(BDC-Br) achieved a higher phenol degradation kinetic rate of 0.106 min–1 at a low dose. Effects of pH, humic acid (HA) and coexisting ions on the degradation of phenol were examined. The FeCu(BDC-Br) /H2O2 system can remove phenol in the near neutral pH range of 4–6 and 0–50 mg/L HA range. Chloride ion, sulfate, or phosphate with a concentration of 100 mg/L showed an inhibitory effect on the catalytical performance of phenol degradation. This work provides insights for the preparation of Fe-MOFs Fenton-like catalyst in water/wastewater treatment.