Mechanochemical modification of kaolin surfaces for immobilization and delivery of pesticides in alginate-chitosan composite beads
The surface modification with poly(methyl hydrosiloxane) (PMHS) using a grinding method as a pesticide carrier had been successfully achieved. The characteristics of the modified kaolin were represented by Fourier transform infrared, X-Ray diffraction, BET specific surface area measurements, laser particle size analysis, transmission electron microscopy and contact angle measurement. Subsequently, immobilization of acetamiprid onto clay’s surface was carried out by means of freeze-drying technology. And the drug-loaded clays were encapsulated in alginate-chitosan composite beads by extrusion into calcium chloride solution. The composite beads showed regularly spherical shapes and uniform sizes with diameters of 1.44 ± 0.24–1.75 ± 0.19 mm. The immobilization and release of acetamiprid were carried out to examine the effect of the modified kaolin on the properties of the composite bead. The results showed that the intensive force of superfine pulverization during the grinding process was effective to increase the specific surface areas of the modified kaolin with particle size reduction. The modified kaolins as promising carrier materials had improved the drug loading rate and encapsulation efficiency from 4.15 and 42.01 % for alginate-chitosan composite beads to 6.02 and 82.95 %, which were higher than 4.33 and 54.29 % for SA-CS-kaolin composite beads, respectively. The controlled-release formulation containing the modified kaolin had shown slow and sustained release properties to promote the efficient use of organic pesticide to reduce pollution effect on the environment.
危险品化学品经营许可证（带存储）