High-density dispersion of CuNx sites for H2O2 activation toward enhanced Photo-Fenton performance in antibiotic contaminant degradation

In this study, a copper-based catalyst (CuCN) with CuNx active sites highly dispersed in a porous carbon nitride matrix was synthesized and applied to a heterogeneous photo-assisted Photo-Fenton (PF) system to degrade tetracycline (TET). The results showed that the CuCN/PF system degraded up to 93.6% of TET within 60 min for ultrapure water matrix under the best experimental conditions, and more than 70% of TET for both river and lake water matrix. Toxicological tests suggested that the environmental risk caused by TET can be effectively inhibited by the CuCN/PF system. The good visible-light response and charge transport abilities of CuCN catalyst were identified in photoelectrochemical experiments. Free radical scavenging experiments and electron paramagnetic resonance (EPR) spectroscopy indicated that the active species in the degradation process were·OH, h+,·O2- and 1O2. Density functional theory (DFT) calculations revealed the positive effect of CuNx sites in CuCN on the formation of hydroxyl radicals by activating H2O2. This work will provide a new insight for the development of high-efficiency heterogeneous catalysts in wastewater environmental remediation. [Display omitted] •Copper-based catalysts were designed for heterogeneous photo-assisted Photo-Fenton processes.•CuNx can effectively avoid the loss of catalytic active components.•CuCN/PF system can achieve efficient removal of persistent pollutants.•This research provides approach for applying nitrogen-rich materials in wastewater treatment.