Synthesis of Nano-Fe@NdFeB/AC magnetic catalytic particle electrodes and application in the degradation of 2,4,6-trichlorophenol by electro-assisted peroxydisulfate process

Abstract

ABSTRACT The coupling of electrolysis and the peroxydisulfate (PDS) activation was selected in this study to degrade solution-phase 2,4,6-trichlorophenol (TCP). To enhance the PDS activation efficiency and catalytic recycling ratio, a novel magnetic activator, nano iron coated on neodymium iron boron/activated carbon nanocomposite (Nano-Fe@NdFeB/AC), was synthesized and utilized as catalytic particle electrodes. To increase the mass transfer ability, a novel magnetic internal circulation electrolytic reactor (MICE) was established. The results indicated that globular Fe, with sizes ranging from 25 nm to 300 nm, is present on the surface of the catalyst. This catalyst has sufficient magnetism to be separated by the magnetic separation method and its specific saturation magnetization and residual magnetization were 1.48 and 0.26 emu/g, respectively. At the optimal condition of [pH]0 = 9.0, [Na2S2O8]0 = 2.0 mmol/L, [Nano-Fe@NdFeB/AC]0 = 5.0 g/L and I = 50 mA, the TOC percentage of removal could reach 84% after 30 min of reaction. The TCP mineralization follows pseudo-first-order kinetics. The intermediate products of 2,6-dichloro-2,5-cyclohexadiene-1,4-dione, Tetrachloro-hydroquinone, and 2,3,5,6-tetrachloro-p-benzoquinone were found during the reaction. TCP mineralization was confirmed to have a hybrid mechanism involving reductive dechlorination with Fe, •OH addition oxidation and electron capture by SO•4 −. This study provides a new method for the treatment of degradation-resistant pollutants.