Fan Yuanyuan, Sun Shanshan, He Shengbing
School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China.
School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China; Shanghai Engineering Research Center of Landscape Water Environment, Shanghai 200031, China.
Water Res. 2023 May 15;235:119837. doi: 10.1016/j.watres.2023.119837. Epub 2023 Mar 6.
Ecological restoration of wetland plants has emerged as an environmentally-friendly and less carbon footprint method for treating secondary effluent wastewater. Root iron plaque (IP) is located at the important ecological niches in constructed wetlands (CWs) ecosystem and is the critical micro-zone for pollutants migration and transformation. Root IP can affect the chemical behaviors and bioavailability of key elements (C, N, P) since its formation/dissolution is a dynamic equilibrium process jointly influenced by rhizosphere habitats. However, as an efficient approach to further explore the mechanism of pollutant removal in CWs, the dynamic formation of root IP and its function have not been fully studied, especially in substrate-enhanced CWs. This article concentrates on the biogeochemical processes between Fe cycling involved in root IP with carbon turnover, nitrogen transformation, and phosphorus availability in CWs rhizosphere. As IP has the potential to enhance pollutant removal by being regulated and managed, we summarized the critical factors affecting the IP formation from the perspective of wetland design and operation, as well as emphasizing the heterogeneity of rhizosphere redox and the role of key microbes in nutrient cycling. Subsequently, interactions between redox-controlled root IP and biogeochemical elements (C, N, P) are emphatically discussed. Additionally, the effects of IP on emerging contaminants and heavy metals in CWs rhizosphere are assessed. Finally, major challenges and outlooks for future research in regards to root IP are proposed. It is expected that this review can provide a new perspective for the efficient removal of target pollutants in CWs.
湿地植物的生态修复已成为一种环保且碳足迹较小的处理二级出水废水的方法。根际铁膜（IP）位于人工湿地（CWs）生态系统的重要生态位，是污染物迁移和转化的关键微区。根际IP的形成/溶解是一个受根际生境共同影响的动态平衡过程，因此它会影响关键元素（碳、氮、磷）的化学行为和生物有效性。然而，作为进一步探究人工湿地污染物去除机制的有效方法，根际IP的动态形成及其功能尚未得到充分研究，尤其是在基质强化人工湿地中。本文重点关注人工湿地根际中根际IP的铁循环与碳周转、氮转化和磷有效性之间的生物地球化学过程。由于IP有通过调控和管理来增强污染物去除的潜力，我们从湿地设计和运行的角度总结了影响IP形成的关键因素，并强调了根际氧化还原的异质性以及关键微生物在养分循环中的作用。随后，着重讨论了氧化还原控制的根际IP与生物地球化学元素（碳、氮、磷）之间的相互作用。此外，还评估了IP对人工湿地根际新兴污染物和重金属的影响。最后，提出了关于根际IP未来研究的主要挑战和展望。期望本综述能为人工湿地高效去除目标污染物提供新的视角。
