摘要：

用水热法和冷冻干燥法制备了MnFe₂O₄-rGO气凝胶催化剂，活化过一硫酸盐（PMS）产生强氧化性的硫酸根自由基（SO₄^·-）氧化降解酸性红B。用SEM、XRD、FTIR、拉曼光谱仪、N2吸脱附等温仪对该催化剂进行表征，考察催化剂投加量、PMS浓度、初始pH对酸性红B降解效果的影响。结果表明，当催化剂投加量为0.15 g/L、PMS浓度为0.6 mmol/L、pH为7时，反应30 min后酸性红B的降解率为91.5%；且pH适用范围广，pH在3~9时降解率均在82%以上。投加自由基捕获剂叔丁醇和甲醇，结果表明在MnFe₂O₄-rGO气凝胶/PMS体系中起氧化降解作用的主要活性物质是SO₄^·-。紫外可见光谱表明酸性红B分子中的萘环结构和偶氮键被氧化；TOC表征结果表明MnFe₂O₄-rGO气凝胶/PMS体系对酸性红B的矿化率为30.8%。

关键词: 石墨烯, 气凝胶, 铁酸锰, 过一硫酸盐

Abstract:

The MnFe₂O₄-rGO aerogel catalyst was synthesized by hydrothermal method and freeze-drying, which was applied to activate peroxymonosulfate(PMS) to produced strong oxidizing sulfate radical(SO₄^·-) for oxidative degradation of acid red B. SEM, XRD, FTIR, Raman spectrometer and N₂ adsorption desorption isotherm were used to characterize the catalyst. The effects of the dosage of MnFe₂O₄-rGO aerogel, PMS concentration and the initial pH on the degradation of acid red B were investigated. The results showed that the degradation rate of acid red B was 91.5% within 30 min with 0.15 g/L of MnFe₂O₄-rGO, pH=7 and 0.6 mmol/L PMS, and the degradation rate at pH=3-9 was above 82% means that the applicable pH range was wide. In addition, the main active species in the MnFe₂O₄-rGO aerogel/PMS system was identified as SO₄^·- by adding radical quencher such as methanol and tert-butanol. The change in the UV-visible spectrum during the degradation process indicated that the naphthalene ring and azo bond in the acid red B molecule were oxidized. The result of TOC showed that the MnFe₂O₄-rGO aerogel/PMS system had 30.8% of the mineralization rate of acid red B.

Key words: graphene, aerogel, manganese ferrite, peroxymonosulfate

中图分类号: 

• X703