MOFs-derived Cu/Carbon membrane as bi-functional catalyst: Improving catalytic activity in detection and degradation of PFOA via regulation of reactive Cu species

Developing bi-functional materials to simultaneously detect and degrade persistent pollutant perfluorooctanoic acid (PFOA) is of significant importance for environmental and human health. In this study, a copper-based mimic enzyme colorimetric detecting sensor coupling with solar photo-electro-Fenton degradation (SPEF) system was built based on Cu/carbon nanofiber (CNF-Cu/C) membrane. Self-supporting flexible CNF-Cu/C membrane was successfully prepared by solvothermal method with further secondary seed growth and in-situ thermal reduction. Based on calcination temperature regulation, the obtained CNF-Cu/C membrane derived from MOFs/polyacrylonitrile (HKUST/PAN) membrane was characterized by 3D carbon fiber network dispersed with porous carbon skeleton embedded copper species, which exhibited good dispersibility, cycling stability and excellent electrical conductivity. With excellent peroxidase-like activity, CNF-Cu/C can rapidly detect PFOA based on the inhibition of color reaction of tetramethylbenzidine (TMB) with detection limit of 0.133 μM. Furthermore, CNF-Cu/C also exhibited outstanding optical properties and oxygen redox reaction (ORR) activity, and the removal efficiency of PFOA in Cu-SPEF system reached 98.22 % within 180 min under optimal conditions. Based on the results of free radical quenching experiment, EPR experiment and HPLC-MS experiments, the degradation mechanism and degradation path of PFOA by SPEF system were further speculated.