An encapsulant system was prepared via crosslinking of chitosan using citric acid as a crosslinker. FTIR spectroscopy, particle size and zeta potential analyses confirmed successful crosslinking, appropriate particle size and colloidal stability. Encapsulation capability of the said material was investigated using fluorescence spectroscopy. The effect of pH on the crosslinked chitosan particles was also conducted.

A coated nitrogen-phosphorus-potassium (NPK) fertilizer was prepared via crosslinking chitosan and alginate using citric acid. Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), particle size analysis, and zeta potential measurement showed the successful crosslinking, appropriate size, and colloidal stability of the coated NPK fertilizer. The encapsulation capability of the crosslinked chitosan/alginate (Chi/Alg) was studied using fluorescence spectroscopy and NPK analysis. The release behavior studies under various pH conditions showed that Chi/Alg NPK conformed to the standards of controlled release fertilizer with a maximum release rate of 40% for 30 days. The investigation of the release mechanism using Korsemeyer-Peppas mathematical model showed that the release of nutrients is governed by both coating material relaxation and diffusion process.

A carboxymethylcellulose-based encapsulant system for the controlled release of nitrogen-phosphorus-potassium (NPK) fertilizer was synthesized using alginate as a stabilizer, and citric acid as a crosslinking agent. Fourier-transform infrared (FT-IR) spectroscopy, particle size analysis, zeta potential measurement, and scanning electron microscopy showed successful crosslinking, sufficient particle size and colloidal stability, as well as the topography of the formed particles. Fluorescence spectroscopy confirmed successful encapsulation of a model system, 8-anilino-1-napthalenesulfonic acid. Release behavior studies under various pH conditions showed that CMC/Alg NPK conformed to the standards of controlled release fertilizer with a maximum release rate of 50% over the span of 30 days.