Fe3O4@Graphite电极中性条件下电Fenton降解有机污染物

DEGRADATION OF ORGANIC POLLUTANT BY Fe_3O_4@GRAPHITE ELECTRODE IN NEUTRAL ELECTRO-FENTON SYSTEM

制备了Fe3O4复合石墨电极(Fe3O4@graphite),通过循环伏安测定,对自制电极的电化学特性进行了表征.在外加电压无隔膜反应池中,基于Fe3O4@graphite为阴极,铂网为阳极,在pH7.0中性条件下,探讨了降解有机染料罗丹明B(Rhodamine B,RhB)及无色小分子2,4-二氯苯酚(2,4-dichlorophenol,DCP)的电Fenton反应特性,结果表明,对1.0×10-5mol.l-1RhB在外加电压6 V和支持电解质Na2SO410 g.l-1条件下,电Fenton反应120 min,RhB降解率达100%.采用过氧化物酶催化反应吸光光度法和苯甲酸荧光分析法跟踪测定RhB降解反应过程中H2O2和羟基自由基(.OH)的变化,表明RhB降解过程涉及.OH历程.采用红外光谱分析和TOC测定RhB降解过程中深度氧化变化,表明电Fenton反应条件下,RhB反应过程中其分子结构被破坏,生成羧酸或者胺类小分子化合物,同时180 min矿化率达59.2%,对2,4-DCP而言,240 min降解率为98.6%,14h矿化率为86.8%.

In this study,Fe3O4 and graphite were combined with Poly（tetrafluorothylene）（PTEF） and used as a composite electrode.Cyclic voltammetry（CV） experiment was performed to probe the electrochemical characteristics of the Fe3O4@Graphite electrode.In the undivided reaction pool,the degradation reaction of organic dye Rhodamine B（Rhodamine B,RhB） and 2,4-dichlorophenol（2,4-DCP） was studied in the neutral pH electro-Fenton system,using Fe3O4 @ graphite as the cathode and platinum net as the anode.It was found that 100% degradation of 1.0×10^-5 mol·l^-1 RhB was achieved in 120 min with applied voltage of 6 V and supporting electrolyte of 10 g·l^-1 Na2SO4,pH 7.0 Horseradish peroxidase（POD） and benzoic acid fluorescence analysis method were used to detect the concentration of hydrogen peroxide（H2O2） and hydroxyl radicals（·OH）,respectively.The results showed that electro-catalytic degradation of RhB involved to ·OH radical mechanism.Infrared spectrum（IR） and total organic carbon（TOC） measurements were used in the process of deep degradation of RhB,and the results indicated that the molecular structure of RhB was disrupted and converted into carbonyl compounds and amines.Meanwhile,the mineralization rate reached 59.2% in 180 min.The degradation and mineralization rates of 2,4-DCP were 98.6% in 240 min and 86.8% in 14 hours,respectively.