Integrating 2D nanomaterials with organic acid–mediated rock phosphate solubilization for enhanced phosphorus availability: a review

Abstract

Phosphorus (P) is an essential but often limiting macronutrient in agriculture due to the poor solubility of naturally occurring rock phosphate (RP). Organic acids released by plant roots or phosphate-solubilizing microorganisms can enhance RP dissolution; however, their effectiveness is restricted by rapid degradation, soil buffering, and strong adsorption to mineral surfaces. A key limitation arises from the strong adsorption of organic acids onto the soil matrix, particularly in soils rich in 2 : 1 clays and exchangeable calcium, where anions such as citrate become bound to clay surfaces or form Ca–organic-anion complexes instead of dissolving phosphate minerals. This adsorption paradoxically increases phosphate fixation rather than reducing it. To overcome these constraints, two-dimensional (2D) nanomaterials such as graphene oxide (GO), MoS₂, and layered double hydroxides (LDHs) have emerged as potential carriers for both organic acids and phosphate. Their high surface area, tunable functionality, and strong binding affinity enable controlled acid release, sustained proton activity, and reduced P fixation at the RP interface. This review synthesizes recent advances in 2D material-assisted organic acid solubilization of RP and highlights future directions toward hybrid nano-bio systems particularly the integration of biochar-2D material composites as a promising next-generation platform for sustainable phosphorus management in agriculture. This review provides a comprehensive synthesis of molecular mechanisms, highlights emerging nano-enabled smart fertilizer strategies, and identifies key future research directions to bridge laboratory insights and field-scale applications. The work presents a novel interdisciplinary framework for improving P accessibility through hybrid nano-bio interventions.