Efficient degradation of tetracycline with N-rGO/CuO catalysts under high salinity condition via persulfate activation dominated by non-radical pathways

The degradation of organic pollutants under high-salt conditions is significant for the resource utilization and environmental remediation. In this work, nitrogen-doped graphene supported copper oxide (N-rGO/CuO, NGC) was synthesized to activate persulfate (PS) for tetracycline (TC) degradation. The TC removal rate reached 97% within 90 min and the catalyst showed high resistance to saline ions. Dual catalytic effects of N and Cu sites on NGC significantly improved the PS activation and the TC oxidation by dominated non-radical reactions involving 1O2 and electron transfer. The dopped N provided more active sites for PS activation and promoted the generation of 1O2. Besides, the CuO loaded on nitrogen-doped graphene enhanced the adsorption of PS and reinforced the oxidative degradation of TC by accelerating electron transfer. Moreover, the successful COD removal from real high salinity wastewater demonstrated that PS activation on NGC is a promising method for treating organic pollutants under high-salt environment.