Interactions of organic phosphorus with soil minerals and the associated environmental impacts: A review

Abstract

As an important part of the soil phosphorus (P) pool, organic P (OP) is widely found in terrestrial and aquatic environments (e.g., soils and sediments). The interfacial behavior of OP on natural minerals affects the transport, transformation, and bioavailability of P in the environment. This paper reviews the processes involving adsorption-desorption, dissolution-precipitation, and enzymatic/mineral-mediated hydrolysis of OP at the mineral-water interface, and their subsequent effects on OP speciation and mineral colloidal stability/reactivity. The sorption mechanisms of OP on natural minerals mainly include surface complexation and precipitation, which are controlled by factors such as mineral identity and crystallinity, the relative molecular weight of OP, reaction pH, ionic strength, temperature, and co-existing ligands or ions. The desorption amount and rate of OP from minerals are determined by the mineral identity, desorbent type, pre-sorption time, OP species, reaction pH, number of desorption cycles, and redox status. The interactions between OP and minerals affect the sorption of co-existing metal ions and the stability of the minerals. The effect of minerals on the enzymatic hydrolysis of OP sorbed on mineral surfaces depends on the mineral identity and OP species. Some minerals also exhibit catalytic activity to promote the cleavage of C–O–P bonds and OP hydrolysis. We provide an overview of state-of-the-art techniques currently applied in environmental OP research. The main challenges and future research directions are also summarized to further explore OP interactions with natural minerals in complex environmental settings.