Fe-Cu铁内电解处理甲基橙的谱学表征

Abstract

应用紫外-可见光谱(uV-VIS)、质谱(MS)和电子顺磁共振(EPr)对甲基橙印染废水在fE-Cu铁内电解中的变化进行跟踪表征.研究结果表明,PH=3时,甲基橙在fE-Cu(质量比1∶1)和fE-Cu-Mn(质量比1∶1∶0.05)铁内电解体系中随着反应时间的增加在400—600nM区域uV-VIS吸收峰面积逐渐减少;fE-Cu-Mn(质量比1∶1∶0.05)吸收峰迅速蓝移至350—550nM区域,且吸收峰面积也逐渐减少.MS正负离子模式测得甲基橙准分子离子峰强度逐渐减小,但相应还检测到由于甲基橙分子断裂引起的逐渐变多的诸如芳香类和苯环裂解后共轭二烯物质的碎片信息.EPr检测到fE3+、fE2+的信号略有增加,在fE-Cu-Mn(质量比1∶1∶0.05)中Mn2+的6条超精细结构谱峰由弱转强.这些研究表明,在fE-Cu铁内电解中甲基橙降解的原因之一是氧化还原反应破坏发色基团,即偶氮双键的消失,引起甲基橙溶液脱色;另一原因是在微电场中,甲基橙分子断裂为更小质荷比的分子离子碎片而引起甲基橙脱色降解,这些研究结果为探索甲基橙溶液在铁内电解中脱色、降解机理提供有力的理论依据.

The change of methyl orange in Fe-Cu iron internal electrolyzer was examined by UVVi S,MS and EPR.The results showed that UV-Vi S absorption peak in the range of 400—600 nm decreased with the increase of the reaction time in Fe-Cu( mass ratio 1 ∶ 1) and Fe-Cu-Mn( mass ratio 1 ∶ 1 ∶ 0.05) iron internal electrolyzer when the solution p H was 3.Positive and negative ion mode MS displayed that the quasi-molecular or ion peaks of methyl orange gradually decreased,but the fragments produced by the degradation of methyl orange were detected.EPR signals assigned to Fe2 +and Fe3 +increased slightly and the six fine peaks assigned to Mn2 +changed from weak to strong signal.These results indicated that one of the degradation routes of methyl orange is that the azo double bond was destroyed by oxidation-reduction reaction in Fe-Cu iron internal electrolyzer,which results in the decoloration of methyl orange.Another route was that in weak electric field,methyl orange was broken down to smaller fragments with lesser m / z.It is helpful to explore the efficiency of catalytic degradation and the degradation mechanism in the decoloration of methylorange in iron internal electrolyzer.