Removal performance and mechanism of humic acid by persulfate activated with ultraviolet light combined with magnetic ion exchange resin
Humic acid(HA)in water was removed by activating persulfate with ultraviolet light combined with magnetic ion exchange resin.The removal efficiency of HA,the environmental factors affecting the removal of HA,the generation mechanism of active oxidizing species and the removal mechanism of HA in the ultraviolet light/persulfate/magnetic ion exchange resin(UV/PMS/MIEX)system were explored.The UV/PMS/MIEX synergistic system had a significant removal efficiency for HA in water,and the removal efficiency reached 91.71％after 120 minutes of reaction.The increase in resin dosage and temperature promoted HA removal,and increasing the concentration of persulfate could improve the removal efficiency of HA to a certain extent,but the effect of solution pH on the removal of HA was not obvious.In this system,the removal of HA was mainly through oxidation,and the adsorption effect WAs not significant.The iron oxides on the surface of the resin,the oxygen-containing functional groups and the addition of ultraviolet rays could effectively activate persulfate to produce various active oxidizing species such as·OH,SO4·-,O2·-,and 1O2.In this system,HA fractions were degraded by the radical and non-radical pathways,and the activation mainly occurs through the radical pathway.Based on the characterization of N2 adsorption-desorption isotherms,Fourier transform infrared spectroscopy,X-ray diffraction spectroscopy,and X-ray photoelectron spectroscopy before and after the reaction,it can be found that the magnetic ion exchange resin exhibits good reusability and stability,and can effectively adsorb and remove various by-products in the system.This study provides a new method for HA removal in water,and the constructed oxidation system shows a good application prospect.
ultraviolet lightpersulfatemagnetic ion exchange resinhumic acidadvanced oxidation
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