多酚物质催化Fe3O4/Fenton降解MB的研究

On the methylene blue degradation with Fe3O4/Fenton enhanced with the polyphenol organics

为了探究多酚物质在异相Fenton反应体系中的作用,以商用Fe3O4为催化剂,亚甲基蓝（Methylene Blue,MB）为目标污染物,研究了外加邻苯二酚（Catechol）和没食子酸（Gallic Acid,GA）对Fe3O4异相Fenton降解MB的影响。考察了多酚浓度、H2O2浓度、溶液初始p H值等因素对MB去除的影响,并探究了其降解机理。结果表明,在体系Fe3O4质量浓度为1.0 g/L、MB浓度为0.1 mmol/L、H2O2浓度为160 mmol/L、初始p H值为7.3的条件下,分别加入0.1 mmol/L的邻苯二酚和0.1 mmol/L的GA,MB的去除率由63%分别增加至79%和90%。多酚的加入不仅能够促进Fe3O4对MB的吸附,提高MB在催化剂表面的局部浓度,还能够增强Fe3O4对H2O2的催化分解能力,产生更多的羟基自由基（·OH）,从而促进了MB的去除,同时显著减少了H2O2的用量,提高了H2O2的利用效率。

In this paper,the author is inclined to make an investigation to determine the influence of the addition of catechol and gallic acid（GA）on the degradation efficiency of the methylene blue（short for MB）through a heterogeneous Fenton reaction with the commercial-purposed Fe3O4as a catalyst and methylene blue（MB）as the target pollutant.In proceeding with our study,it has been found that,when catechol and GA were added to the surfacce of Fe3O4/Fenton catechol and GA,the said system tends to get negatively charged.In such a case,the isoelectric points of the Fe3O4would be getting to 4.2,while the zeta potentials of Fe3O4due to the addition of catechol and GA may turn to be all negative within the p H value range of 2.0-9.0.What is more,with the increase of the negative charges due to the increase of the p H value,it can be found that the addition of Fe3O4/Fenton can promote the adsorptive power so as for them to be charged onto the surface of Fe3O4.And,then,it would be possible for the negatively charged Fe3O4to adsorb much more MB as a kind of cationic dye,which is in favor of enriching MB on the surface of Fe3O4.The results of the above investigation indicate that the removal efficiency of MB desorbed by Fe3O4can merely be of 7%.However,the removal efficiency of MB desorbed by Fe3O4can be promoted up to 17%and 52%with the respective addition of 0.1mmol/L catechol and 0.1 mmol/L GA.Besides,if the addition of 0.1 mmol/L catechol and 0.1 mmol/L GA can be respectively added to Fe3O41.0 g/L,MB 0.1 mmol/L,H2O2160 mmol/L,it would be possible for the MB removal efficiency to be enhanced from 63%to 79%and even 90%,correspondingly.Therefore,the yields of·OH with Fe3O4,with the help of a catalyst in addition of catechol or GA can be made much higher than that of the pure Fe3O4.Thus,the addition of catechol and GA can not only promote the adsorption of MB but also can enhance the catalytic ability of Fe3O4,so as to increase the yield of·OH.And,so,the H2O2utilization efficiency can also be heightened with the dosage of H2O2dramatically reduced.