Process optimization for the preparation of thiamethoxam microspheres by response surface methodology

摘要

4A zeolite has reasonable adsorption and frame support properties thanks to its special pore structure and large surface area. This paper aims at improving the properties of microspheres by introducing zeolite as structural modifier. Therefore, the 4A zeolite/sodium alginate (SA)/Chitosan (CS) thiamethoxam microspheres (4A/SA/CS MCs) were hereby prepared and optimized through Response Surface Methodology. The Box-Behnken design was used to build the model and to analyze the effects of the concentration of sodium alginate, calcium chloride and 4A zeolite on the response value-loading efficiency. Furthermore, the fabricated 4A/SA/CS MCs were characterized by fourier transform infrared spectroscopy, scanning electron microscope, X-ray diffraction, differential scanning calorimetry. The performances of 4A/SA/CS TMCs such as the swelling rate, particle size, slow-release behaviors were systematically investigated. The phytotoxicity and insect activity of 4A/SA/CS MCs were also evaluated. The experimental results illustrated that the relationship between the response value and three independent variables were corresponded with the quadratic model. The properties of microspheres indicated that microspheres containing 4A zeolite had better LE and EE, displayed good sustained-release property and thermal stability, possessed persistent insecticidal activity as well as high biosafety.