还原剂强化Fe(Ⅱ)活化过氧化物高级氧化体系研究进展

Research Progress in Reductant-enhanced Fe(Ⅱ) Activated Peroxide Advanced Oxidation Processes

Fe^(2+)活化过氧化物高级氧化体系因其能够产生高活性氧化剂、分解难生物降解有机物、提高废水可生化性,在环境污染治理领域得到广泛关注。但该体系中Fe^(3+)/Fe^(2+)循环速率较慢,制约了目标污染物降解效能的提升。在实际工程中,常通过同步投加铁还原剂强化该高级氧化体系中Fe^(3+)的还原过程,进而提升活性氧化剂的生成效率。常用的铁还原剂主要分为无机还原剂和有机还原剂两大类。无机还原剂包括羟胺、亚硫酸盐、零价金属和碳材料等,有机还原剂包括酚醌类、抗坏血酸和巯基化合物等。还原剂在强化Fe^(3+)/Fe^(2+)循环过程的同时,还有可能竞争消耗过氧化物和淬灭活性氧化剂,且部分还原剂具有生物毒性,不利于规模化应用。总结了各类铁还原剂强化Fe^(2+)活化过氧化物高级氧化体系降解目标污染物的效果、基本机理以及各还原剂的优缺点,为进一步研究开发新型高效环境友好型铁还原剂提供了参考和指导。

The Fe(II) activated peroxidants-based advanced oxidation processes(AOPs) have attracted much attention because they can produce highly reactive oxidants, which are able to degrade refractory organics and thus promote the biodegradability of wastewater. However, the slow rate of Fe(Ⅲ)/Fe(Ⅱ) cycle restricts the promotion of the decontamination efficiency of these AOPs. In practical application, reducing agents of Fe(Ⅲ) are often applied to accelerate the reduction of Fe(Ⅲ), which can improve contaminants degradation efficiency. The commonly used reducing agents of Fe(Ⅲ) can be classified to inorganic and organic species. The inorganic reducing agents include hydroxylamine, sulfite, zero valent metal, and carbon-based materials, while the organic reducing agents contain phenolics, quinone, ascorbic acid, and sulfhydryl compounds. However, reducing agents would also competitively consume peroxidants and reactive oxidants, and more importantly, some of them are toxic. In this work, the reducing mechanism was systematically elucidated, the effects of these reducing agents on improving decontamination efficiency were summarized, and the advantages and drawbacks of these reducing agents were analyzed, which could pave the way for developing novel environmental-friendly Fe(Ⅲ) reducing agents.