The Controlled-release Phosphorus Fertilizer with Silica from Rice Husk

Abstract

The current study was conducted with objectives to study the adsorption process of silica from rice husk, to study the phosphorus content before and after its adsorption in silica, to prepare the phosphorus fertilizer pellets, and to study the release of phosphorus of the prepared fertilizers. The product is used as a controlled-release fertilizer. The rice husk after calcined at 900 °C for 6 h. got 12% of the silica, which qualified as absorbent material by the XRD and FT-IR techniques. The porous silica has phosphorus contents at 15.20 g/kg; 1.52% in the raw material. After soaking with 20 ppm P2O5, the phosphorus was increased to 38.13 g/kg (3.81%). The phosphorous content of the sample was over the organic fertilizer standard. The pellet fertilizers from silica were prepared by compressing the mixture of silica and binder, which can be maintained as the fertilizer granules for up to 30 days in distilled water. The phosphorus in fertilizer powder released up to 79.35% in 648 h while tablets released 48.72% at the same time. The powder phosphorus fertilizer was found to be a standardized controlled-release fertilizer while the pallet fertilizer can be considered an excellent fertilizer as it has high phosphorus content and slow-release capability. It indicates that the mesoporous silica from the rice husk is one of the alternative components to prepare the controlled-release fertilizer.