Enhanced Peroxymonosulfate Activation by a Benzoquinone-Functionalized Carbon Nanotube Filter for Micropollutant Degradation

Abstract

The utilization of redox-active quinone-like compounds to activate peroxymonosulfate (PMS) has become a viable method for decontaminating polluted water. However, redox-active compounds must be added ex situ as oxidant activators, which leads to secondary pollution. Herein, we present a rationally designed new carbon nanotube nanohybrid filter that is modified with benzoquinone-containing diamine monomers (AQPDA) for the activation of PMS to achieve the efficient decomposition of micropollutants. The hybrid filtration system effectively avoids secondary contamination and eliminates the need for electricity, thus enhancing the viability and sustainability of the technology. Sulfamethoxazole (SMX) is used to assess the effectiveness of the system and to identify the key operational parameters. With optimized operational parameters for the system, 100% of the SMX can be removed within 40 min in recirculating flow mode. Experiments with radical quenching and electron paramagnetic resonance studies proved that nonradical routes were the dominant process for the destruction of SMX. Based on the experiments, working mechanisms and degradation pathways were proposed. Experimental results illustrated that the system could resist the interference of background substances in water such as inorganic anions and humic acid. This research offers a promising route for environmental remediation using quinone-loaded carbon nanotubes.