Unveiling the Role of Polysulfide Matrices in Phosphate Diffusion for Controlled Release Fertilizers

Abstract

Phosphate rock and struvite (ST) dispersion in a polysulfide (PS) matrix offers a sustainable alternative for phosphorous (P) fertilization, as it can favor P dissolution and control its release, while also being a sulfur fertilizer. Herein, we discuss the PS permeability mechanism as well as the chemical and structural factors that affect P diffusion from PS composites. SEM and contact angle showed that P particles increased PS porosity and hydrophilicity, which favors P release. Within 7 days in soil, Fe-oxide papers revealed that the Pdiffusion diameter was only 0.3 cm for ST against up to 2.3 cm from the PS composite. In 28 days, available P in soil from the apatite increased from 6 to up to 79 mg/dm 3 due to its dispersion in PS. In the adapted Ussing Chamber permeability test, PS displayed higher affinity toward anion permeability and a negligible cation diffusion, which might contribute to the gradual P release and higher availability in soil.

A Comprehensive Exploration of Polysulfides, From Synthesis Techniques to Diverse Applications and Future Frontiers

“…The release of fertilizer is controlled by the composition of nutrients and the size of the composite particles. Using sulfur polymer as a fertilizer component introduces many advantages, like sulfur, a nutrient, and polymer sources such as sulfates. − Figure shows the released sulfate amount for specific cultivation time and pH. These sulfur-based commercial fertilizers were synthesized from the inverse vulcanization process through soybean oil.…”