Synthesized and accumulated by a vast variety of bacteria and planktons, polyphosphates (polyP) constitute a significant portion of phosphorus (P) in dissolved phase, sinking particulates and sediments in aquatic environment, making it a key player in global P cycling. Despite its environmental significance, little is known about its transport and fate. This work investigated the mineral adsorption, enzymatic hydrolysis and transformation of linear polyP with different chain lengths. The adsorption of these polyP onto iron and aluminum oxide minerals was studied by quartz crystal microbalance with dissipation (QCM-D) and 31P solid state nuclear magnetic resonance spectroscopy (NMR). Results suggested that polyP were irreversibly adsorbed with a “side-on” configuration on the minerals, and the adsorption amount was dependent on chain length and pH. The polyP can be catalytically hydrolyzed by alkaline phosphatase, and most likely through the terminals, as supported by 31P liquid NMR. In the presence of Ca2+, calcium phosphate precipitate formed and was identified to be amorphous, as suggested by X-ray diffraction and scanning electron microscopy with X-ray microanalysis. Effects of mineral sorption and solution chemistry on polyphosphate transformation are being conducted and will be characterized by P K-edge X-ray absorption spectroscopy. Results from this study provide a mechanistic understanding of reactions governing the mobility and transformation of polyp in aquatic environment, therefore, improves our understanding of the P cycle.

Sorption, degradation and transformation of polyphosphates: Implications for understanding the biogeochemical cycling of polyphosphate

251st National Meeting (2016)

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