aDepartment of Soil Science, Gobind Ballabh Pant University of Agriculture and Technology, Pantnagar, 263 145, Udham Singh Nagar, Uttar Pradesh, India
Department of Chemistry, Gobind Ballabh Pant University of Agriculture and Technology, Pantnagar, 263 145, Udham Singh Nagar, Uttar Pradesh, India
Online published on 31 October, 2011.
The kinetics of adsorption of tralkoxydim on Ca - and Cu - kaolinite and bentonite clays is reported. The adsorption equilibrium was reached in 12 h in Ca - and Cu - kaolinite and took 24 and 48 h respectively in Cu - and Ca - bentoniie clayss Thh easorption ccoformed to tth eirst order kinetics in two distinct steps, an initial faster adsorption followed by a relatively slower one. Among different models of adsorption kinetics namely single constant -, two conssants -- Elooichh and parabolic diffusion-models, two constants model fitted best to the adsorption data of both the clays and gave the highest value of correlation co-efficient and lowest value of weighted mean square deviate. The calculated values of initial adsorption rate for kaolinite were about two folds higher than those for bentonite. Cu-clays showed slightly higher initial adsorption rate co-efficient than Ca - clays. The maximum adsorption values for tralkoxydim were 5.26, 5.68,4.87 and 7.77 mg g−1 for Cu - kaolinite;; bentonite, Ca-kaolinite and-bentoniie clays, respecttvely.
Tralkoxydim, adsorption kinetics, bentonite, kaolinite, homoionic clays
