Emerging lanthanum (III)-containing materials for phosphate removal from water: A review towards future developments

Yue Zhi, Chuhui Zhang, Rune Hjorth, Anders Baun, Owen W Duckworth, Douglas F Call, Detlef R U Knappe, Jacob L Jones, Khara Grieger*

*Corresponding author for this work

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Abstract

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 (LaPO4·H2O), 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.

Original languageEnglish
Article number106115
JournalEnvironment International
Volume145
Number of pages11
ISSN0160-4120
DOIs
Publication statusPublished - 2020

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Copyright © 2020 The Author(s). Published by Elsevier Ltd.. All rights reserved.

Cite this

Zhi, Y., Zhang, C., Hjorth, R., Baun, A., Duckworth, O. W., Call, D. F., Knappe, D. R. U., Jones, J. L., & Grieger, K. (2020). Emerging lanthanum (III)-containing materials for phosphate removal from water: A review towards future developments. Environment International, 145, [106115]. https://doi.org/10.1016/j.envint.2020.106115