废旧电池资源化回收制备铁锰双金属催化剂及活化过硫酸盐的机理研究

The recycling of spent batteries is significant in economical point of view to resource and materials. In this proposal, Fe-Mn bimetallic catalysts will be fabricated from spent alkaline batteries and used to activate persulfate (PS) for the removal of refractory organic contaminants in water. The mechanism of heterogeneous activation of persulfate will be investigated. It includes the determination of reactive species (RS) generated in the Fe-Mn bimetallic catalysts/persulfate system, the transformation of Mn and Fe with different valent state during heterogeneous activation process and the role of surface hydroxyl groups on Fe-Mn bimetallic catalysts in the persulfate activation. In this system, nonradical processes may be contributed to the degradation of organic pollutant. Therefore, the generation of singlet oxygen and its contribution to the removal efficiency of organic pollutant will be examined. The direct electron transfer between Mn and target organics will also be explored. The degradation products of target contaminant will be identified and the corresponding degradation pathway will be proposed. The stability and reusability of Fe-Mn bimetallic catalysts will be evaluated by successive cycling experiments. The effects of other metal impurities in waste batteries on the removal of target pollutants will be investigated. The research of this project will not only provide ideas for the recycling of waste Zn-Mn alkaline batteries, but also give theoretical basis and guide for the control of refractory organic contaminants in water by heterogeneous activation of persulfate process using Fe-Mn bimetallic catalysts fabricated from waste batteries as catalyst.

废旧电池中含有丰富的金属资源，将废旧电池中的锰和铁等主要金属元素回收制备催化剂用于水中有机污染物的处理是废旧电池资源化的一种有效方式。本项目以废旧碱性电池为原料制备铁锰双金属催化剂，并用于活化过硫酸盐处理水中的难降解有机污染物。研究铁锰双金属催化剂/过硫酸盐体系中的活化机理，包括活化过程中产生的活性物质种类、Mn和Fe不同价态间的转化和不同pH条件下催化剂表面羟基官能团与过硫酸盐的结合方式及对过硫酸盐分解速率的影响。探究单线态氧及Mn与污染物间电子转移等非自由基过程对污染物的降解。分析目标污染物在自由基和非自由基过程产生的中间降解产物并确定降解路径。考察铁锰双金属催化剂的稳定性和废旧电池中的其他金属杂质对目标污染物去除率的影响。本项目的实施不仅能为废旧锌锰电池的资源化回收利用提供思路，且能为铁锰双金属催化剂活化过硫酸盐体系处理水中的难降解有机污染物的广泛应用提供理论支撑。

本项目以废旧锰锌碱性电池为原料制备锰铁双金属Mn2O3-Fe2O3催化剂，并用于活化过一硫酸盐(PMS)降解水中多种难降解有机污染物。研究了污染物对乙酰氨基酚在不同初始pH条件下的去除及其降解路径。重复实验表明Mn2O3-Fe2O3有相对良好的稳定性和可循环性。通过抑制剂实验，电子顺磁共振，和电化学测试，确定了Mn2O3-Fe2O3活化PMS的机理，污染物对乙酰氨基酚的氧化去除是通过从污染物到催化剂表面吸附的PMS的电子转移过程实现的。Mn2O3-Fe2O3活化PMS体系对不同的有机污染物呈现出选择性氧化能力。线性自由能关系分析结果显示，若污染物的氧化峰电位（Eop）大于0.91 V (Mn2O3-Fe2O3活化PMS体系的稳态开路电位)，则其较难被氧化降解；若污染物的Eop 小于0.91 V，则其容易被氧化降解，且该污染物的反应速率常数（k1）与Eop之间呈现较好的线性相关性。此Mn2O3-Fe2O3活化PMS体系提供了一种较新的、低成本的，且环境友好的体系，可以实现废旧电池资源的有效回收利用，并且有效去除有机污染物，也可以为非自由基电子转移过程、选择性氧化和LFER分析提供相关的研究思路。

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