Synergistic Combination of Graphitic Carbon Nitride and Peroxymonosulfate for Efficient Photocatalytic Destruction of Emerging Contaminants under Simulated Solar Irradiation

Abstract

The prevalence of micropollutants (MPs) and antibiotic resistance in various aquatic environments has raised increasing concerns for public health and ecological security. Conventional wastewater treatment processes exhibit a relatively limited removal efficiency to these contaminants. Although photocatalytic processes are proposed as an effective solution, very few studies have investigated the simultaneous removal of chemical and biological contaminants. To develop a "onestop" photocatalytic process, this study combined urea-based graphitic carbon nitride (g-C 3 N 4 ) with peroxymonosulfate (PMS) and evaluated its performance in the simultaneous removal of multiple MPs, antibioticresistant bacteria (ARB), and antibiotic resistance genes (ARGs) at environmentally relevant concentrations. The system removed 87% of MPs (10 μg/L each) and achieved 6.5-log ARB reduction within a 5 min treatment. In addition, the concentrations of extracellular ARGs (e-tetA and e-bla TEM-1 ) were rapidly decreased, with 4.8-log and 6.7-log reductions after a 30 min treatment, respectively. Atomic force microscopy images showed that the naked plasmid DNA was destructed. Radical quenching and electron paramagnetic resonance experiments further confirmed that both radical and nonradical pathways are involved in ARB inactivation in a g-C 3 N 4 /PMS photocatalytic system. Collectively, the g-C 3 N 4 /PMS photocatalytic system can efficiently achieve simultaneous removal of MPs and ARB as well as ARG destruction, therefore being a promising "one-stop" decontamination solution. KEYWORDS: graphitic carbon nitride (g-C 3 N 4 ), photocatalysis, micropollutants (MPs), antibiotic-resistant bacteria (ARB), antibiotic resistance genes (ARGs), peroxymonosulfate (PMS)