铁酸锰-石墨烯气凝胶活化PMS降解酸性红B

Degradation of acid red B with peroxymonosulfate activated by MnFe_(2)O_(4)-rGO aerogel

用水热法和冷冻干燥法制备了MnFe_(2)O_(4)-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(SO_(4)^(·-))氧化降解酸性红B。用SEM、XRD、FTIR、拉曼光谱仪、N_(2)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MnFe_(2)O_(4)-rGO气凝胶/PMS体系中起氧化降解作用的主要活性物质是SO_(4)^(·-)。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MnFe_(2)O_(4)-rGO气凝胶/PMS体系对酸性红B的矿化率为30.8%。

The MnFe_(2)O_(4)-rGO aerogel catalyst was synthesized by hydrothermal method and freeze-drying,which was applied to activate peroxymonosulfate(PMS)to produced strong oxidizing sulfate radical(SO_(4)^(·-))for oxidative degradation of acid red B.SEM,XRD,FTIR,Raman spectrometer and N_(2) adsorption desorption isotherm were used to characterize the catalyst.The effects of the dosage of MnFe_(2)O_(4)-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 MnFe_(2)O_(4)-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 MnFe_(2)O_(4)-rGO aerogel/PMS system was identified as SO_(4)^(·-)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 MnFe_(2)O_(4)-rGO aerogel/PMS system had 30.8%of the mineralization rate of acid red B.