He Ting, Sun Jie, Deng Liangwei, Ming Jialin, Hu Changwei
Key Laboratory of Green Chemistry and Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610064, China; Biogas Institute of Ministry of Agriculture and Rural Affairs, Chengdu 610041, China.
Biogas Institute of Ministry of Agriculture and Rural Affairs, Chengdu 610041, China; Inner Mongolia Key Laboratory of Fine Organic Synthesis, Inner Mongolia University, Hohhot 010021, China.
J Environ Sci (China). 2025 Jan;147:523-537. doi: 10.1016/j.jes.2023.12.013. Epub 2023 Dec 27.
Due to its high efficiency, Fe(II)-based catalytic oxidation has been one of the most popular types of technology for treating growing organic pollutants. A lot of chemical Fe sludge along with various refractory pollutants was concomitantly produced, which may cause secondary environmental problems without proper disposal. We here innovatively proposed an effective method of achieving zero Fe sludge, reusing Fe resources (Fe recovery = 100%) and advancing organics removal (final TOC removal > 70%) simultaneously, based on the in situ formation of magnetic Ca-Fe layered double hydroxide (FeO@CaFe-LDH) nano-material. Cations (Ca and Fe) concentration (≥ 30 mmol/L) and their molar ratio (Ca:Fe ≥ 1.75) were crucial to the success of the method. Extrinsic nano FeO was designed to be involved in the Fe(II)-catalytic wastewater treatment process, and was modified by oxidation intermediates/products (especially those with COO structure), which promoted the co-precipitation of Ca (originated from Ca(OH) added after oxidation process) and by-produced Fe cations on its surface to in situ generate core-shell FeO@CaFe-LDH. The oxidation products were further removed during FeO@CaFe-LDH material formation via intercalation and adsorption. This method was applicable to many kinds of organic wastewater, such as bisphenol A, methyl orange, humics, and biogas slurry. The prepared magnetic and hierarchical CaFe-LDH nanocomposite material showed comparable application performance to the recently reported CaFe-LDHs. This work provides a new strategy for efficiently enhancing the efficiency and economy of Fe(II)-catalyzed oxidative wastewater treatment by producing high value-added LDHs materials.
由于其高效率，基于Fe(II)的催化氧化一直是处理日益增多的有机污染物最受欢迎的技术类型之一。同时产生了大量化学铁污泥以及各种难降解污染物，如果处理不当，可能会导致二次环境问题。在此，我们创新性地提出了一种有效的方法，基于原位形成磁性Ca-Fe层状双氢氧化物（FeO@CaFe-LDH）纳米材料，同时实现零铁污泥产生、铁资源再利用（铁回收率 = 100%）并提高有机物去除率（最终总有机碳去除率 > 70%）。阳离子（Ca和Fe）浓度（≥ 30 mmol/L）及其摩尔比（Ca:Fe ≥ 1.75）对该方法的成功至关重要。外在的纳米FeO被设计参与Fe(II)催化的废水处理过程，并被氧化中间体/产物（特别是具有COO结构的那些）修饰，这促进了Ca（源自氧化过程后添加的Ca(OH)₂）和副产的Fe阳离子在其表面共沉淀，以原位生成核壳结构的FeO@CaFe-LDH。在FeO@CaFe-LDH材料形成过程中，氧化产物通过插层和吸附进一步被去除。该方法适用于多种有机废水，如双酚A、甲基橙、腐殖质和沼液。制备的磁性且具有分级结构的CaFe-LDH纳米复合材料表现出与最近报道的CaFe-LDHs相当的应用性能。这项工作通过生产高附加值的LDHs材料，为有效提高Fe(II)催化氧化废水处理的效率和经济性提供了一种新策略。
