An attempt has been made in this paper to develop simple and easily understandable thermodynamic parameters related with the formation of activated complex and sorption process at equilibrium. The overall scenario represented by thermodynamic parameters was found to be a better indicator of understanding the process. Because it gives a general idea whether the process is exothermic or endothermic and also whether the process is stable or unstable. Sorption of 2,4-dichloro-phenoxy-acetic acid (2,4-D) and 2-chloro-4-ethyalamino-6-isopropylamino-s-traiazine (atrazine) on rubber granules followed second order reversible kinetic equation. 2,4-D-rubber granules system showed endothermic nature while atrazine-rubber granules showed exothermic nature. The values of E-a (associated with formation of activated species) were in the range of 3.49 kcal/mol and -2.40 kcal/mol for 2,4-D and atrazine, respectively. During equilibrium condition, both the systems showed negative Gibb's energy, which indicates stability of system. (C) 2004 Elsevier B.V. All rights reserved.