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Adsorption of phosphate by halloysite (7Å) nanotubes (HNTs)

Gray-Wannell, N.; Holliman, P.J.; Greenwell, H.C.; Delbos, E.; Hillier, S.

Adsorption of phosphate by halloysite (7Å) nanotubes (HNTs) Thumbnail


N. Gray-Wannell

P.J. Holliman

E. Delbos

S. Hillier


The adsorption and retention of phosphates in soil systems is of wide environmental importance, and understanding the surface chemistry of halloysite (a common soil clay mineral) is also of prime importance in many emerging technological applications of halloysite nanotubes (HNTs). The adsorption of phosphate anions on tubular halloysite (7 Å) has been studied to gain a greater understanding of the mechanism and kinetics of adsorption on the surface of HNTs. Two well-characterized tubular halloysites with differing morphologies have been studied: one polygonal prismatic and one cylindrical, where the cylindrical form has a greater surface area and shorter tube length. Greater phosphate adsorption of up to 42 μmol g–1 is observed on the cylindrical halloysite when compared to the polygonal prismatic sample, where adsorption reached a maximum of just 15 μmol g–1 compared to a value for platy kaolinite (KGa-2) of 8 μmol g–1. Phosphate adsorption shows strong pH dependence, and the differences in phosphate sorption between the prismatic and cylindrical morphologies suggest that phosphate absorption does not occur at the same pH-dependent alumina edge sites and that the lumen may have a greater influence on uptake for the cylindrical form


Gray-Wannell, N., Holliman, P., Greenwell, H., Delbos, E., & Hillier, S. (2020). Adsorption of phosphate by halloysite (7Å) nanotubes (HNTs). Clay Minerals, 55(2), 184-193.

Journal Article Type Article
Acceptance Date Jul 30, 2020
Online Publication Date Aug 6, 2020
Publication Date 2020-06
Deposit Date Jul 30, 2020
Publicly Available Date Oct 6, 2020
Journal Clay Minerals
Print ISSN 0009-8558
Electronic ISSN 1471-8030
Publisher Mineralogical Society
Peer Reviewed Peer Reviewed
Volume 55
Issue 2
Pages 184-193


Published Journal Article (558 Kb)

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Copyright Statement
&copy; The Author(s), 2020. Published by Cambridge University Press on behalf of The Mineralogical Society of Great Britain and Ireland. This is an Open Access article, distributed under<br /> the terms of the Creative Commons Attribution licence (, which permits unrestricted re-use, distribution, and reproduction in any medium, provided the original work is properly cited.

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