The effect of zeolite addition and freeze-drying method on alginat beads for controlled release fertilizer

Abstract

The effect of zeolite on alginate beads for fabrication of Controlled Release Fertilizer (CRF) and using freeze drying method during manufacturing have been studied. CRF fabrication was done by mixing of alginate, zeolite and liquid NPK fertilizer followed by dipping into CaCl2 solution. The effect of zeolite was determined by the release of Nitrogen (N), Phosphorus (P) and Potassium (K) from A/Z/NPK and A/NPK bead. The CRF preparation using freeze-drying methods for A/NPK beads was also compared with air-drying method. The CRF products were characterized by using FTIR and SEM. Analysis of N, P and K was done by Kjeldahl method, UV-Vis and AAS. Swelling test (SR) of the beads and chemical reaction kinetics were investigated. The result showed that A/Z/NPK composite beads could be used as Controlled Release of NPK fertilizer and showed better capability than beads of A/NPK. The freeze-drying during beads formation showed better performance than air-drying method. The addition of zeolite and freeze-drying method is effective to enhance the swelling ratio of A/NPK. The chemical reaction kinetics model representing of A/Z/NPK, A/NPK beads using air and freeze-drying is Korsmeyer-Peppas model.