Preparation and Properties of Pesticide/Cyclodextrin\nComplex Intercalated into ZnAl-Layered Double Hydroxide

Abstract

Inclusion\ncomplexes were formed by including the pesticide beta-cypermethrin\n(BC) in sulfonated hydroxyethyl-β-cyclodextrin (SHECD) and sulfobutyl\nether β-cyclodextrin (SBECD), and these complexes were then\nintercalated into the galleries of layered double hydroxides (LDHs)\nto synthesize BC/SHECD–LDH and BC/SBECD–LDH hybrids.\nThe hybrids were characterized by powder X-ray diffraction (XRD),\nFourier transform infrared (FT-IR) spectroscopy, thermogravimetry/differential\nthermal analysis (TGA/DTA), and scanning electron microscopy (SEM).\nThe results showed that BC/SHECD–LDH and BC/SBECD–LDH\nhad basal spacings of 1.64 and 2.12 nm, respectively, which were analyzed\non the basis of the structural properties of cyclodextrin (CD). The\ncombustion temperature of interlayer SHECD was increased by 140 °C\nthrough intercalation. Furthermore, the release behaviors of BC from\nBC/SHECD–LDH and BC/SBECD–LDH composites were investigated.\nThe release of BC from the hybrids was faster at pH 6.8 than at pH\n5.0, and the released amounts were higher at the former pH, in close\ncorrelation with the structural type of CD and the release media.\nThe BC release kinetic processes were well-fitted with pseudo-second-order\nand parabolic diffusion models. BC/SHECD–LDH could potentially\nbe applied for pesticide formulation.