Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education, College of Environment and Ecology, Chongqing University, Chongqing 400044, China; Department of Civil, Construction, and Environmental Engineering, North Carolina State University, Raleigh, NC 27695, USA.
Department of Civil, Construction, and Environmental Engineering, North Carolina State University, Raleigh, NC 27695, USA.
Environ Int. 2020 Dec;145:106115. doi: 10.1016/j.envint.2020.106115. Epub 2020 Sep 17.
The last two decades have seen a rise in the development of lanthanum (III)-containing materials (LM) for controlling phosphate in the aquatic environment. >70 papers have been published on this topic in the peer-reviewed literature, but mechanisms of phosphate removal by LM as well as potential environmental impacts of LM remain unclear. In this review, we summarize peer-reviewed scientific articles on the development and use of 80 different types of LM in terms of prospective benefits, potential ecological impacts, and research needs. We find that the main benefits of LM for phosphate removal are their ability to strongly bind phosphate under diverse environmental conditions (e.g., over a wide pH range, in the presence of diverse aqueous constituents). The maximum phosphate uptake capacity of LM correlates primarily with the La content of LM, whereas reaction kinetics are influenced by LM formulation and ambient environmental conditions (e.g., pH, presence of co-existing ions, ligands, organic matter). Increased La solubilization can occur under some environmental conditions, including at moderately acidic pH values (i.e., < 4.5-5.6), highly saline conditions, and in the presence of organic matter. At the same time, dissolved La will likely undergo hydrolysis, bind to organic matter, and combine with phosphate to precipitate rhabdophane (LaPO·HO), all of which reduce the bioavailability of La in aquatic environments. Overall, LM use presents a low risk of adverse effects in water with pH > 7 and moderate-to-high bicarbonate alkalinity, although caution should be applied when considering LM use in aquatic systems with acidic pH values and low bicarbonate alkalinity. Moving forward, we recommend additional research dedicated to understanding La release from LM under diverse environmental conditions as well as long-term exposures on ecological organisms, particularly primary producers and benthic organisms. Further, site-specific monitoring could be useful for evaluating potential impacts of LM on both biotic and abiotic systems post-application.
过去二十年见证了含镧（III）材料（LM）在控制水生环境中磷酸盐方面的发展。在同行评议文献中，已经有>70 篇关于这个主题的论文发表，但 LM 去除磷酸盐的机制以及 LM 的潜在环境影响仍不清楚。在这篇综述中，我们根据预期效益、潜在生态影响和研究需求，总结了 80 种不同类型 LM 的开发和使用的同行评议科学文章。我们发现，LM 去除磷酸盐的主要优点是它们能够在各种环境条件下（例如，在宽 pH 范围内，在存在各种水成分的情况下）强烈结合磷酸盐。LM 的最大磷酸盐吸收容量主要与 LM 中的镧含量相关，而反应动力学受 LM 配方和环境条件（例如，pH 值、共存离子、配体、有机物的存在）的影响。在某些环境条件下，例如在中等酸性条件（即 pH 值<4.5-5.6）、高盐条件和有机物存在的条件下，可能会发生镧的可溶性增加。同时，溶解的镧可能会发生水解，与有机物结合，并与磷酸盐结合形成磷灰石（LaPO·HO），所有这些都会降低水生环境中镧的生物利用度。总体而言，在 pH 值>7 和中等至高碳酸氢盐碱度的水中，LM 的使用带来的不良影响风险较低，尽管在考虑将 LM 用于 pH 值较低和碳酸氢盐碱度较低的水生系统时应谨慎行事。未来，我们建议进行更多研究，以了解 LM 在不同环境条件下的镧释放情况以及对生态生物的长期暴露情况，特别是对初级生产者和底栖生物的影响。此外，特定地点的监测可能有助于评估 LM 对生物和非生物系统的潜在影响。
Zotero 插件