The adsorption characteristics of poly-carboxylate dispersant(Tersperse 2700)onto imidacloprid particle surfaces

such as adsorption thermodynamics

kinetics

adsorption force and adsorption conformation

were studied with determining adsorption amounts by remnants of concentration

adsorption layer thickness and Fourier transform infrared spectroscopy.The thermodynamic parameters obtained are as follows:ΔHad<0

ΔGad<0

ΔSad>0

indicating that the adsorption is a spontaneous exothermic process.The adsorption layer thickness decreases as temperature increases.Theoretically

higher temperature is not beneficial to adsorption process.The result of adsorption kinetics shows that the adsorption of dispersant 2700 onto imidacloprid particle surfaces corresponds with Lagergren adsorption rate equation.The adsorption rate increases with temperature and activation energy Ea=12.62 kJ·mol-1

so the adsorption process is physical adsorption.The result of adsorption force shows that van der Waals force is an important force at different temperatures.The adsorption is monolayer and multi-point.The hypothetical adsorption model shows that the adsorption stability on imidacloprid particle surfaces is maintained by apparent stereo-hindrance effect and electrostatic repulsion produced by dispersant 2700.