Controlled release formulation of zinc hydroxide nitrate intercalated with sodium dodecylsulphate and bispyribac anions: A novel herbicide nanocomposite for paddy cultivation

Abstract

Bispyribac (BP) anions have been successfully intercalated in the interlayer region of zinc hydroxide nitrate (ZHN) in the presence of sodium dodecylsulphate (SDS) surfactant. The physicochemical properties of the intercalation compound ZHN–SDS–BP have been characterised herein with different instrumental techniques. The intercalation of BP and SDS is clearly reflected in the PXRD analysis, based on the appearance of symmetrical, sharp and intense intercalation peaks at lower 2θ with a basal spacing of 28.2–28.6 Å. The thermal studies show that the ZHN–SDS–BP nanocomposite has better thermal stability than the pristine BP. The intercalation of BP leads to significant changes in the surface area, porosity, and morphology. Nitrogen adsorption–desorption isotherms reveal that both ZHN–SDS and ZHN–SDS–BP are of Type IV. The release and kinetic studies were also carried out on the ZHN–SDS–BP, in aqueous solution of Na3PO4, Na2SO4 and NaCl as the release media. The releases of BP in both aqueous solutions of Na3PO4 and NaCl were found to follow the pseudo second order kinetic model, whereas the releases of BP in the aqueous solution of Na2SO4 obey the parabolic diffusion kinetic model. This study shows that ZHN has the potential to be used as a host material in slowing the release of BP herbicides in the paddy cultivation sector. Keywords: Nanocomposite, Bispyribac, Zinc hydroxide nitrate, Sodium dodecylsulphate, Intercalation