Dynamics of Controlled Release of Potassium Nitrate from a Highly Swelling Binary Biopolymeric Blend of Alginate and Pectin

Novel polymeric sodium alginate (Na‐Alg) beads have been prepared by crosslinking Na‐Alginate–pectin blend using CaCl₂ as a crosslinking agent to form biopolymeric beads. A series of beads of varying composition were prepared by varying the amounts of sodium alginate, pectin and CaCl₂ in the feed mixture. These beads were loaded with KNO₃ taking as a model agrochemical and used for release of KNO₃. The prepared unloaded and loaded sodium alginate and pectin beads were characterized by FTIR spectral and Scanning Electron Microscopy (SEM) techniques to investigate the molecular structure and morphology of beads, respectively. The swelling experiments were performed for different compositions of beads and at varying pH and temperature of the aqueous media. The release of KNO₃ was investigated for 8 days in 25 ml of distilled water as a release medium. The release experiments were performed under static and varying experimental conditions and the release data obtained conductometrically were fitted to Ficks equation to evaluate diffusion coefficients of released potassium nitrate. The release results were further analyzed by Ficks power law equation, and the possible mechanisms of KNO₃ release were explored at different experimental conditions.

Keywords:

• calcium alginate
• pectin
• swelling
• potassium nitrate
• release

Acknowledgement

The authors acknowledge the Indian Institute of Technology, Mumbai, India for their kind assistance in carrying out FTIR and SEM analysis of unloaded and KNO₃ loaded biopolymeric beads.