不同形貌二氧化锰活化过一硫酸盐降解水中罗丹明B的研究

多相活化过一硫酸盐(PMS)技术已经成为催化降解水中有机污染物的重要技术,活化PMS的过程不但可以产生硫酸根自由基,也可以产生羟基自由基。本研究通过水热合成方法合成了3种MnO_2,其中两种分别为棒状和线状的一维MnO_2纳米结构,还有一种无特定形貌的α-MnO_2。通过活化PMS降解水中的罗丹明B(Rh B),对比了3种催化剂的活性,发现线状MnO_2的催化活性最高。通过考察不同因素对线状MnO_2催化活性的影响,得出水中Rh B降解的最佳条件为:Rh B浓度10μg/g,PMS浓度0.5g/L,线状MnO_2浓度0.3g/L,温度35℃,pH=8。通过自由基消除试验探究了其活化PMS降解水中Rh B的机理,表明硫酸根自由基在降解水中有机污染物中起到了主要作用,详细阐述了PMS活化、硫酸根自由基产生和RhB降解的过程。

PREPARATION OF MANGANESE DIOXIDE CATALYST WITH DIFFERENT MORPHOLOGIES AND PERFORMANCE OF ACTIVATING PMS FOR Rh B DEGRADATION IN AQUEOUS SOLUTIONS

Heterogeneous activation of peroxymonosulfate (PMS) becomes an important technology for degradation of organic compounds in aqueous solutions by generating sulfate radicals and hydroxyl radicals. In this study, three types of MnO2 catalysts were synthesized: two 1D manganese dioxides，nanorods and nanowires, and one α-MnO2 without a specific appearance. The catalytic performance of three MnO2 catalysts for Rh B degradation in aqueous solutions through activated PMS was compared. The results indicated that the nanowire MnO2 has the highest activity. By investigating the influence of different factors on the catalytic activity of nanowire MnO2, the best conditions for the degradation of Rh B in water are as follows: 35℃，pH=8, Rh B concentration of 10μg/g, PMS 0.5 g/L and nanowire MnO2 0.3 g/L. By the experiments of eliminating radicals, the mechanism for Rh B degradation in aqueous solution through activating PMS was studied, indicating that the sulfate radical from PMS activation plays an important role in degradation of organic compounds. The activation of PMS, the generation of sulfate radical and the process of Rh B degradation are illustrated in detail.