聚多巴胺/聚乙烯亚胺复合非织造布/Fe^2+活化过硫酸盐催化氧化酸性红B的效果分析

Effect analysis of catalytic oxidation of acid red B by polydopamine/polyethyleneimine nonwoven/Fe^2+activated persulfate

以聚丙烯(PP)非织造布为基体,采用多巴胺聚乙烯亚胺共沉积法制备了聚多巴胺/聚乙烯亚胺复合非织造布(PDA/PEI@PP),研究了PDA/PEI@PP在Fe^2+活化过硫酸盐(PS)降解酸性红B(ARB)的中的性能和反应机理。通过SEM对材料结构进行了表征,考察了不同体系(PS、PDA/PEI@PP/PS、Fe^2+/PS和PDA/PEI@PP/Fe^2+/PS)中ARB的降解效果,通过电子自旋共振波谱(ESR)和傅里叶红外光谱(FT-IR)分析了PDA/PEI@PP活化PS及自由基生成的机理,此外,考察了PDA/PEI@PP对Fe^3+的还原作用。结果表明:PDA/PEI@PP非织造材料具有贯穿的孔道结构,利于PDA/PEI@PP表面官能团对PS的活化;PDA/PEI@PP对Fe^2+/PS体系的催化氧化具有促进作用,当Fe^2+初始浓度为0.5 mmol·L^−1时,90 min内对ARB的降解率为98%,反应速率常数为0.040 min^−1;在不添加Fe^2+的情况下,PDA/PEI@PP可直接活化PS产生自由基降解ARB,降解率为56%;PDA/PEI@PP表面的邻苯二酚基团与邻醌基反应生成半醌,从而活化PS产生硫酸根自由基(SO4^-)和羟基自由基(·OH);同时PDA/PEI@PP表面的邻苯二酚基团也对Fe^3+具有还原作用,生成Fe^2+持续活化PS。因此,PDA/PEI@PP对于Fe^2+活化PS的促进作用主要是通过PDA/PEI@PP对PS协同活化和对Fe^3+的还原作用来实现的。本研究为进一步提高Fe^2+活化PS氧化降解染料废水的效率提供了一种较好的解决方案。

In this study,polypropylene(PP)nonwoven was taken as matrix,the co-deposition method of dopamine and polyethyleneimine was used to prepare the polydopamine/polyethyleneimine-functionalized polypropylene nonwoven(PDA/PEI@PP).The performance and mechanism of PDA/PEI@PP on Fe^2+activated persulfate(PS)and degrading acid red B(ARB)were studied.SEM was used to characterize the PDA/PEI@PP material.The ARB degradation effects in different systems of PS,PDA/PEI@PP/PS,Fe^2+/PS and PDA/PEI@PP/Fe^2+/PS were also studied.Electron spin-resonance spectroscopy(ESR)and Fourier transform infrared(FT-IR)were used to identify the mechanism of PDA/PEI@PP activated PS and radicals formation.In addition,the reduction of Fe^3+by PDA/PEI@PP was investigated.The results showed that the throughout pore structure was presented in PDA/PEI@PP nonwoven material,which facilitated PS activation by the surface functional groups of PDA/PEI@PP.PDA/PEI@PP could promote the catalytic oxidation of Fe^2+/PS system,the degradation rate of ARB could reach 98%within 90 min when the initial content of Fe^2+was 0.5 mmol·L^−1,and the reaction rate constant was 0.040 min^−1.Without the addition of Fe^2+,PDA/PEI@PP could directly activate PS,produce radicals for ARB degradation with a rate of 56%.On the surface of PDA/PEI@PP,the catechol groups reacted with o-quinone groups to produce semiquinone,which could activate PS and produce sulfate radical(SO4^-)and hydroxyl radical(·OH).At the same time,the catechol groups on the surface of PDA/PEI@PP also could reduce the Fe3+to Fe2+,which could sustainably activate PS.Therefore,the promoting effects of PDA/PEI@PP on Fe^2+activated PS are mainly due to the synergetic activation of PS and Fe^3+reduction by PDA/PEI@PP.The study provides a better solution for further improving the efficiency of oxidation degradation of dye wastewater by Fe^2+activated PS.