Process Optimization Potassium Nanofertilizer Production via Ionotropic Pre-gelation using Alginate-Chitosan Carrier

Abstract

Potassium nanofertilizer synthesis by incorporating potassium in alginate-chitosan carrier via ionotropic pre-gelation was optimized to maximize potassium content and develop controlled release fertilizer. Utilizing two-level factorial design, potassium to alginate ratio, calcium chloride to alginate ratio, and pre-gelation time were determined significant. Central Composite Design for optimization was utilized to generate a Response Surface model relating the factors to the response for numerical optimization. Optimum process conditions for maximum potassium content were (1) 1.5:1 (w/w) potassium to alginate ratio, (2) 6.5:117.5 (v/v) calcium chloride to alginate ratio, and (3) 40 minutes pre-gelation time. The potassium content of the fertilizer formulated at optimum condition was successfully verified to contain 29.75 %K(w/w). Characterization showed that potassium was successfully incorporated in the alginatechitosan carrier as shown by the SEM surface images. DLS result showed two peaks at particle sizes near 594.1 nm and 102.8 nm indicating that potassium nanofertilizer was successfully synthesized. Potassium nanofertilizer may be a controlled release fertilizer since only 14.6 %K was released after 24 hours in Britton-Robinson buffer solution. Preliminary costing shows higher cost of production based on raw materials, but it may be offset in the long run by longer availability of nutrient and low fertilizer application rate.