Preparation and performance of hymexazol/lignin based amphoteric surfactant/bentonite slow-release formulation.

The use of slow-release formulation of pesticide is an effective strategy to reduce environmental pollution. In order to develop a slow-release formulation of low cost and with release regulation capability, and enhance the added value of lignin products, we used lignin-based amphoteric surfactant (dimethyl-butyl-sulfonated lignin ammonium chloride: DBSLAC) as modification agent to exchange the metal ions between the layer of sodium-based bentonite which was used as raw material, and prepared modified bentonite. Hymexazol was selected as the drug for release, and was loaded on modified bentonite. Hymexazol slow-release formulation was prepared by means of adsorption, its performance was studied, and its structure was characterized by FT-IR. The basal spacing of modified bentonite was analyzed with XRD. The results showed that with an increase of DBSLAC dosage, the adsorption capacity that modified bentonite adsorped hymexazol first increased and then decreased, and the optimum adsorption effect for acetaniprid was 1.2 CEC. Compared to the unmodified bentonite, the adsorption effect for hymexazol increased. The optimum adsorption conditions for hymexazol were L-1.2Bt dosage 0.02 g, adsorption time 8 h, mass concentration of acetaniprid 500 mg/L and pH 2. Under these conditions, the maximum adsorption capacity was 406 mg/g. The water soluble method indicated that potion proportion and temperature had certain effect on the accumulative release rate of L-1.2Bt.