Sonicated Carbon Nanotube Catalysts for Efficient Point-of-use Water Treatment.

Abstract

The rising demand for freshwater and increasing contamination of distributed water sources, such as stormwater and surface water, necessitate innovative point-of-use treatment technologies. Advanced oxidation processes (AOPs) using solid oxidants offer a promising approach for decentralized freshwater production but are often limited by nonselective radical reactions that degrade both pollutants and background water constituents. Here, sonicated carbon nanotubes (CNTs) that efficiently activate peroxymonosulfate are demonstrated, enabling selective contaminant degradation via dual nonradical pathways-singlet oxygen oxidation and direct electron transfer. Optimized sonication introduces catalytically active carbonyl (C═O) groups on CNT surfaces while preserving their graphitic structure, ensuring rapid electron transfer. This approach achieves 2,4-dichlorophenol removal, a common industrial and municipal pollutant, within 5 min at a record removal rate of 4.80 µmol g^-1 s^-1. Furthermore, scalable CNT catalyst synthesis and integration into flat membrane and hollow fiber filtration devices, ensuring long-term stability and efficient pollutant removal in natural river water, are demonstrated. By advancing selective CNT catalysts for AOPs, this work offers a scalable, sustainable solution for point-of-use freshwater production in real-world applications.