加剧的全球水资源短缺和更严格的水指令正在导致再生水使用的增加,需要开发新的具有成本效益的高级水处理方法,为人口提供安全的水。在这个意义上,过乙酸(PAA,CH3C(O)OOH)是一种环境友好的消毒剂,有可能在不久的将来挑战大型污水处理厂中氯的主导地位。PAA可以作为H2O2的替代氧化剂进行Fenton反应,最近证明,在中性pH值和阴离子存在下,它比H2O2更有效地降解新兴污染物。PAA通过均相和非均相铁基材料活化产生-除了HO•和FeO2-更有选择性的CH3C(O)O•和CH3C(O)OO•自由基,被典型的HO·猝灭剂稍微清除(例如,碳酸氢盐),将PAA的用途扩展到复杂的水基质。这反映在过去几年中铁-PAA出版物的指数级进展中。尽管最近发表了一些关于PAA一般性质和在水处理中的用途的评论,铁基材料对PAA活化的研究和环境应用没有说明,尽管取得了可喜的进展。鉴于这些陈述,在这里,我们对铁基PAA活化系统的类型进行了全面审查,并分析了迄今为止采用的各种铁化合物(例如,亚铁和三价铁盐,高铁酸盐(VI),尖晶石铁氧体),使用外部铁还原/螯合剂(例如,吡啶甲酸,l-半胱氨酸,硼)和紫外可见光照射系统,分析每个案例所涉及的机制。铁与PAA活化的比较还讨论了其他过渡金属(特别是钴)。这项工作旨在提供对基于Fe/PAA的过程的透彻了解,促进对其优点和局限性的有用见解,被忽视的问题,和前景,导致其普及和专有技术的增加。
The exacerbated global water scarcity and stricter water directives are leading to an increment in the recycled water use, requiring the development of new cost-effective advanced water treatments to provide safe water to the population. In this sense, peracetic acid (PAA, CH3C(O)OOH) is an environmentally friendly disinfectant with the potential to challenge the dominance of chlorine in large wastewater treatment plants in the near future. PAA can be used as an alternative oxidant to H2O2 to carry out the Fenton reaction, and it has recently been proven as more effective than H2O2 towards emerging pollutants degradation at circumneutral pH values and in the presence of anions. PAA activation by homogeneous and heterogeneous iron-based materials generates - besides HO• and FeO2+ - more selective CH3C(O)O• and CH3C(O)OO• radicals, slightly scavenged by typical HO• quenchers (e.g., bicarbonates), which extends PAA use to complex water matrices. This is reflected in an exponential progress of iron-PAA publications during the last few years. Although some reviews of PAA general properties and uses in water treatment were recently published, there is no account on the research and environmental applications of PAA activation by Fe-based materials, in spite of its gratifying progress. In view of these statements, here we provide a holistic
review of the types of iron-based PAA activation systems and analyse the diverse iron compounds employed to date (e.g., ferrous and ferric salts, ferrate(VI), spinel ferrites), the use of external ferric reducing/chelating agents (e.g., picolinic acid, l-cysteine, boron) and of UV-visible irradiation systems, analysing the mechanisms involved in each case. Comparison of PAA activation by iron vs. other transition metals (particularly cobalt) is also discussed. This work aims at providing a thorough understanding of the Fe/PAA-based processes, facilitating useful insights into its advantages and limitations, overlooked issues, and prospects, leading to its popularisation and know-how increment.