Kinetics of Benalate Adsorption on Kaolinites

Chemistry Department, D. S. College, Aligarh-202 001

Manuscript received 5 October 1989, revised 25 February 1992, accepted 13 March 1992

Kinetics of benalate adsorption of H-, Na- and Ca-saturated kaolinites have been investigated. The adsorption and desorp­tion rate constants obtained were in agreement with those obtained from the Lindstrom et αl. model, which proved useful in the simultaneous evaluation of adsorption and desorption rate constants. The activation energies, heats of activation and entropies of activation along with thermodynamic parameters were calculated. The rate constants and other parameters indicated a partly physical and a partly chemical adsorption of benalate on clay surface. Adsorption occurs by coordination and/or protonation of the exchangeable cations of the clay with amidic carbonyl group of herbicide and hydrogen bonding and dipole association at the crystal edge and basal surface.