新型自支撑锑锡氧化物电极氧化降解阿特拉津性能研究OA北大核心CSTPCD

Objective Highly active and stable anodes are crucial for efficiently removing persistent organic pollutants such as atrazine(ATZ)using electro-oxidation technology.Sb-doped SnO2(ATO)materials exhibit high oxygen evolution potential,but commonly prepared planar ATO electrodes face removal rate and stability limitations due to slow mass transfer and large charge transfer impedance.This study proposes a compression-sin-tering method using fructose as a pore-forming reagent to prepare self-supporting 3-dimensional porous ATO(Fru-ATO)anodes for highly effi-cient and stable ATZ removal. Methods The Fru-ATO anode is initially prepared using fructose particles as the pore-forming reagent through compression and sintering.The effect of sintering temperature on the anode's structure and performance is investigated by characterizing the electrode morphology and crystallin-ity with scanning electron microscopy(SEM)and X-ray diffraction analyzer(XRD)and analyzing their electro-oxidation performance.Secondly,the optimization of initial solution pH,electrolyte concentration,and applied current density is conducted to achieve a better degradation rate of ATZ.Under optimized conditions,the performance of 1000-Fru-ATO in actual water and cycling tests is investigated.Finally,the reactive oxy-gen species generated on 1000-Fru-ATO are investigated through quenching experiments and in-situ electron paramagnetic resonance character-ization.In addition,intermediate products in the degradation process of ATZ and possible degradation pathways are proposed based on liquid chromatography-triple quadrupole mass spectrometry(UPLC-MS/MS). Results and Discussions With the increase in sintering temperature,the size of particles in the anode increases,the XRD peak becomes sharper and higher,the potential for oxygen evolution reaction gradually shifts positively,and the performance in catalyzing ATZ degradation improves.Based on the 1000-Fru-ATO anode,acidic and neutral initial solutions showed higher ATZ degradation rates,with the corresponding k for pH=6 reaching 0.071 min1.The concentration of Na2SO4 electrolyte exerts a volcano-like influence on the ATZ degradation rate,with the highest k of 0.071 min-1 in 0.1 mol/L.The ATZ degradation rate increases monotonically as the applied current density rises,while the lowest energy con-sumption is observed at 10 mA/cm2.Under the optimized condition of 0.1 mol/L Na2SO4 electrolyte solution at the initial solution pH and an ap-plied current density of 10 mA/cm2,the 1000-Fru-ATO anode degrades 90％of ATZ(20 mg/L)within 30 min and 99％within 60 min and main-tains good cycling stability in a ten-cycle test.With actual water from Xinlin Bay,Xiamen,the 1000-Fru-ATO anode still degrades 90.2％of ATZ(20 mg/L)within 60 min.In addition,the quenching experiment and in-situ electron paramagnetic resonance showed that singlet oxygen is the dominant reactive oxygen species for the rapid ATZ degradation on the 1000-Fru-ATO anode.In addition,17 intermediates of the ATZ de-gradation process are identified by UPLC-MS/MS,based on which three possible degradation pathways are proposed.Five reaction processes are mainly involved in ATZ degradation on the l000-Fru-ATO anode,including dealkylation,dechlorohydroxylation,alkyl hydroxylation,alkyl ox-idation,and hydroxylation.The electrode possesses a 3-dimensional porous structure that exposes more active sites and improves mass transfer ef-ficiency.As a result,the simultaneous enhancement of mass transfer and charge transfer and the suppressed oxygen evolution promotes the gener-ation of three reactive oxygen species,especially singlet oxygen,leading to the effective and rapid degradation of ATZ. Conclusions The results demonstrate the feasibility of the proposed method with fructose pore-forming reagent to prepare highly active and stable ATO anodes for efficiently and stably electro-oxidizing ATZ.This method can also be extended to other catalyst anode preparations and other persistent organic pollutant removals and would inspire more advances in preparing self-supported 3D porous electrodes with organic powder of small molecular weight as pore-forming reagents.