Preprint Article Version 1 Preserved in Portico This version is not peer-reviewed

The Binding of Phosphorus Species at Goethite: A Joint Experimental and Theoretical Study

Version 1 : Received: 4 February 2021 / Approved: 8 February 2021 / Online: 8 February 2021 (07:43:53 CET)

How to cite: Ganta, P.B.; Morshedizad, M.; Kühn, O.; Leinweber, P.; Ahmed, A.A. The Binding of Phosphorus Species at Goethite: A Joint Experimental and Theoretical Study. Preprints 2021, 2021020171 (doi: 10.20944/preprints202102.0171.v1). Ganta, P.B.; Morshedizad, M.; Kühn, O.; Leinweber, P.; Ahmed, A.A. The Binding of Phosphorus Species at Goethite: A Joint Experimental and Theoretical Study. Preprints 2021, 2021020171 (doi: 10.20944/preprints202102.0171.v1).

Abstract

Knowledge of the interaction between inorganic and organic phosphates with soil minerals is vital for improving the soil P fertility. To achieve an in-depth understanding we combined adsorption experiments and hybrid ab initio molecular dynamics simulations to analyze the adsorption of common phosphates, i.e. orthophosphate (OP), glycerolphosphate (GP) and inositolhexaphosphate (IHP), onto the 100 surface plane of goethite. Experimental adsorption data per mol P-molecule basis fitted to the Freundlich model show the adsorption strength increases in the order GP < OP < IHP, and IHP adsorption being saturated faster followed by GP and OP. Modeling results show that OP and GP form stable monodentate (M) and binuclear bidentate (B) motifs with B being more stable than M, whereas IHP forms stable M and 3M motifs. Interfacial water plays an important role through hydrogen bonds and proton transfers with OP/GP/IHP and goethite. It also controls the binding motifs of phosphates with goethite. Combining both experimental and modeling results, we propose that the B motif dominates for OP, whereas GP forms M and IHP forms a combination of M and 3M motifs. The joint approach plausibly explains why IHP is the predominant organically bound P form in soil. This study could be considered as a preliminary step for further studies for understanding the mechanisms of how microbes and plants overcome the strong IHP–mineral binding to implement the phosphate groups into their metabolism.

Subject Areas

P–fertility, orthophosphate, glycerolphosphate, inositolhexaphosphate, goethite, adsorption, surface complexation, MD simulations, QMMM

Comments (0)

We encourage comments and feedback from a broad range of readers. See criteria for comments and our diversity statement.

Leave a public comment
Send a private comment to the author(s)
Views 0
Downloads 0
Comments 0
Metrics 0


×
Alerts
Notify me about updates to this article or when a peer-reviewed version is published.
We use cookies on our website to ensure you get the best experience.
Read more about our cookies here.