Catalytic Performance of Layered Double Hydroxides Co-Mn-Al for Ozonation of Organic Pollutants in Water

The catalytic activity of layered double hydroxides containing Co, Mn, and Al for the ozonation of organic pollutants in water was investigated. The Co-Mn-Al layered double hydroxides were prepared by coprecipitation. Nitrobenzene was used as a model compound, and it was shown that the degradation and mineralization of nitrobenzene was increased by the presence of Co-Mn-Al layered double hydroxides as compared to ozonation alone. Both an indirect method of adding a scavenger (tert-butanol) of the hydroxyl radical chain reaction and direct electron spin resonance using 5,5-dimethyl-1-pyrroline-N-oxide as a spin trapping agent were used to investigate the generation of hydroxyl radicals in the ozonation by the Co-Mn-Al layered double hydroxides. The inhibiting effect of tert-butanol on the degradation of nitrobenzene and the detection of the stronger 5,5-dimethyl-1-pyrroline-N-oxide/hydroxyl radical adduct showed that the Co-Mn-Al layered double hydroxides catalyzed the generation of hydroxyl radicals.

摘要采用共沉淀法制备了 Co-Mn-Al 层状双氢氧化物, 并将其用于以硝基苯为目标污染物的催化臭氧降解反应中. 结果表明, Co-Mn-Al 层状双氢氧化物存在时, 硝基苯的降解和矿化效率较单独臭氧氧化系统显著提高. 采用加入羟基自由基捕获剂 (叔丁醇) 和电子顺磁共振检测 (5,5-二甲基-1-吡咯啉-N-氧化物为捕获剂) 的间接、直接方法, 探讨了 Co-Mn-Al 层状双氢氧化物是否强化了羟基自由基的生成. 结果表明, 加入叔丁醇降低了硝基苯的降解效率; 电子顺磁共振检出了更强的羟基自由基加成物生成信号. Co-Mn-Al 层状双氢氧化物的存在促进了羟基自由基的生成.

Graphical abstractCo-Mn-Al layer doubled hydroxides catalyzed ozone decomposition to hydroxyl radicals, which then degraded organic pollutants in water.Figure optionsDownload full-size imageDownload as PowerPoint slide