石墨烯负载铁锰氧化物活化过一硫酸盐降解金橙G

利用水热法制备了rG-MnFe_2O_4活化剂,通过TEM、XRD、FT-IR、Raman等手段对活化剂进行了系统表征,通过其对偶氮染料OG的降解实验评价了rG-MnFe_2O_4活化PMS的效果,同时考察了PMS浓度、rG-MnFe_2O_4投加量、初始pH、Cl~-浓度对OG降解效果的影响.结果表明,当rG-MnFe_2O_4投加量为0.3 g·L-1,n(PMS)∶n(OG)=40∶1时,rG-MnFe_2O_4活化PMS的效果显著,反应27 min时,OG降解率为100%,并且随PMS浓度、rG-MnFe_2O_4投加量的提高,OG降解效率明显增加.初始pH对OG降解有较大影响,pH=5.00时效果最好.Cl~-对活化降解OG具有促进作用,Cl-浓度越高,OG降解得越快.r G-MnFe_2O_4在重复使用5次时仍具有较好活化性能.通过紫外可见光谱和气相色谱-质谱(GC/MS)对OG降解过程进行分析,表明OG分子中的萘环结构和偶氮键均被破坏,并检测出主要降解产物有对硝基苯酚和邻苯二甲酸;且rG-MnFe_2O_4/PMS降解体系对染料OG具有一定的矿化率.

Degradation of OG with Peroxymonosulfate Activated by a MnFe2O4-graphene Hybrid

The rG-MnFe₂O₄ was synthesized by hydrothermal method and characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and Raman spectra. The rG-MnFe₂O₄ was used to activate peroxymonosulfate (PMS) to decolorize azo dyes, e.g., Orange G, and the effect of PMS dosage, rG-MnFe₂O₄ loadings, initial pH, and the concentration of Cl^- were investigated. The results indicated that the degradation rate of OG was 100% within 27 min with 0.3 g ·L^-1 of rG-MnFe₂O₄ and at a 40:1 of PMS:OG molar ratio. The decolorization efficiency of OG increased with increasing PMS concentration and increasing rG-MnFe₂O₄ dosage. The initial pH had a significant effect on OG degradation, and pH 5.00 was most favorable for its decolorization. In addition, the addition of Cl^- accelerated the decolorization of OG, and the decolorization rate increased with increasing concentration of Cl^-. The rG-MnFe₂O₄ also exhibited an excellent reusability, and its activation of PMS was still observed after five rounds of tests. From the analysis of UV-vis spectra and gas chromatography-mass spectrometry (GC/MS), the naphthalene ring and azo band were found to be destroyed, with p-nitrophenol and phthalic acid as the main degradation products. Finally, a TOC analysis indicated that a certain degree of OG mineralization was obtained in the rG-MnFe₂O₄/PMS system.