Phosphate sorption by three potential filter materials as assessed by isothermal titration calorimetry
Phosphorus eutrophication of lakes and streams, coming from drained farmlands, is a serious problem in areas with intensive agriculture. Installation of phosphate (P) sorbing filters at drain outlets may be a solution. The aim of this study was to improve the understanding of reactions involved in P...
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Published in | Journal of environmental management Vol. 143; pp. 26 - 33 |
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Main Authors | , , , |
Format | Journal Article |
Language | English |
Published |
Kidlington
Elsevier Ltd
01.10.2014
Elsevier Academic Press Ltd |
Subjects | |
Online Access | Get full text |
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Summary: | Phosphorus eutrophication of lakes and streams, coming from drained farmlands, is a serious problem in areas with intensive agriculture. Installation of phosphate (P) sorbing filters at drain outlets may be a solution. The aim of this study was to improve the understanding of reactions involved in P sorption by three commercial P sorbing materials, i.e. Ca/Mg oxide-based Filtralite-P, Fe oxide-based CFH-12 and Limestone in two particle sizes (2–1 mm and 1–0.5 mm), by means of isothermal titration calorimetry (ITC), sorption isotherms, sequential extractions and SEM-EDS. The results indicate that P retention by CFH is due to surface complexation by rapid formation of strong Fe–P bonds. In contrast, retention of P by Filtralite-P and Limestone strongly depends on pH and time and is interpreted due to formation of calcium phosphate precipitate(s). Consequently, CFH can unambiguously be recommended as P retention filter material in drain outlets, whereas the use of Filtralite-P and Limestone has certain (serious) limitations. Thus, Filtralite-P has high capacity to retain P but only at alkaline pH (pH ≥ 10) and P retention by Limestone requires long-time contact and a high ratio between sorbent and sorbate.
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•The Fe oxide-based CFH is a highly efficient phosphate sorbent.•CFH rapidly forms strong Fe–P bonds on Fe oxide surfaces.•P retention by Limestone is slow and requires high sorbent:sorbate ratio.•P retention by Filtralite-P strongly depends on pH with high sorption at pH ≥ 10 but no sorption at pH ≤ 8. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0301-4797 1095-8630 |
DOI: | 10.1016/j.jenvman.2014.04.010 |