Degradation of 2,4-dichlorophenol by carboxymethylcellulose stabilized Fe/Ni activating persulfate system: The DFT calculation and mechanistic insights

2,4-dichlorophenol (2,4-DCP) was degraded by synthesizing a novel carboxymethyl cellulose (CMC) stabilized Fe/Ni nanocomposite and activating persulfate (PS), meaning Fe/Ni-CMC-PS system. The feasibility of the degradation of 2,4-DCP in Fe/Ni-CMC system was determined by the comparison of blank, PS, nZVI, nZVI-PS, Fe/ Ni-CMC and Fe/Ni-CMC-PS systems, respectively. The consequences of different influencing factors showed that the degradation efficiency reached the optimum value of 95.62% when pH was 5.5, Fe/Ni-CMC dose was 0.8 g/L, Fe/Ni ratio was 0.10 (Wt (Fe):Wt (Ni) = 9:1) and PS concentration was 2 mM. At the same time, the inhibition effect of natural organic matter (humic acid) and inorganic anions on the activity of iron-based materials was studied. The quenching experiments showed that SO4.- radical and .OH radical were mainly produced in the reaction system of Fe/Ni-CMC-PS, and SO4.- radical was the primary free radical to degrade 2,4-DCP. Based on the consequences of DFT calculation and experimental analysis, the possible mechanisms of degrading 2,4-DCP by Fe/Ni-CMC-PS was proposed, which provided a novel idea for the actual practice of iron-based materials in the treatment of environmental water pollution.