In this research, carbon nanotube (CNT) was employed to activate peroxydisulfate (PDS) for the degradation of 2,4-dichlorphenol (DCP). The rate of DCP degradation increased with the increasing PDS dose, DCP dose, CNT loading and solution pH. There are three possible mechanisms for DCP removal in this system, including free radical oxidation, surface-bound radical oxidation and non-radical oxidation. The results of radical scavenging experiments and electron paramagnetic resonance (EPR) tests indicated that free radicals oxidation could be ruled out and surface reactions including surface-bound radicals and non-radical oxidation were responsible for DCP degradation. Examination of CNT surface using X-ray photoelectron spectroscopy (XPS) after the experiments showed that CNT surface was chlorinated, which could result from the attack of chlorine-containing organic radical generated from the oxidation of DCP by surface-bound radicals. CNT surface sites contributing to surface-bound radical oxidation were inactivated and lost their catalytic ability after the reaction. The sites that contributed to non-radical oxidation which was responsible for 24% DCP degradation remained intact after the reaction and maintained their functionality for three rounds of experiments.

Degradation of 2,4-dichlorophenol by CNT-activated peroxydisulfate: Radical vs. non-radical mechanisms

2019 Fall National Meeting

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