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生物炭作为一种廉价易得的材料,在土壤修复等各方面的功能已引起广泛关注,但其催化作用却鲜有研究。首次对生物炭(biochar-BC)催化过硫酸盐(Na2S2O8-PS)使偶氮染料金橙Ⅱ(AO7)脱色的可行性进行研究,对影响催化体系脱色效率的因素(包括pH、生物炭质量浓度和PS/AO7摩尔比)进行探讨,同时研究了生物炭的重复利用效果及前后性质变化。结果表明:PS/BC体系明显比单独的PS体系脱色效果好;两个反应体系都遵循一级反应动力学;PS/BC体系反应的最适pH接近中性;生物炭质量浓度越大,脱色效果越好;PS/AO7摩尔比越大,脱色效果越好,但是催化效果却没有相应的改善;生物炭重复利用后对AO7仍然有脱色效果;BC的孔大多位于层状结构表面,且为小孔,重复使用后,表面孔会堵塞;除了灰分和氧元素外,其他元素(C、N、H、S)含量都有一定程度的减小;BC表面官能团种类很多,主要有C=O、C=C、C-O、C-H,芳香族C=C和C-H以及-OH官能团;BC重复使用后-OH峰会消失。综上述,生物炭可以催化过硫酸盐对偶氮染料AO7进行脱色,原理是BC表面的-OH官能团与PS反应生成硫酸根自由基去除AO7。
Biochar, as a cheap and readily available material, has drawn much attention in the fields of soil remediation and other functions, but its catalysis has rarely been studied. The feasibility of biochar-BC catalyzed decolorization of the azo dye Au7 (AO7) by persulfate (Na2S2O8-PS) was studied. The factors affecting the decolorization efficiency of the catalytic system, including pH, Concentration and PS / AO7 molar ratio) were discussed, while the effect of biochar reuse and changes in the nature before and after. The results showed that: PS / BC system significantly better than the PS system decolorization effect; both reaction systems follow the first-order reaction kinetics; PS / BC system reaction is almost neutral pH; the greater the concentration of biochar mass, The better the effect is; the larger the molar ratio of PS / AO7 is, the better the decolorization effect is, but the catalytic effect is not improved correspondingly; after the reuse of biochar, the AO7 still has the decoloring effect; the pores of BC are mostly located on the surface of the layered structure Small pores, surface pores will be blocked after repeated use. The contents of other elements (C, N, H, S) except for ash and oxygen are reduced to a certain degree. There are many kinds of functional groups on BC surface, mainly C = O , C = C, CO, CH, aromatic C = C and CH, and -OH functional groups; the disappearance of the -OH peak after repeated use of BC. In summary, biochar catalyzes the decolorization of the azo dye AO7 by persulfate. The principle is that the -OH functional group on the BC surface reacts with PS to form sulfate radical to remove AO7.