The adsorption of 4,4'-iso-propylidene diphenol (BPA), and diphenylolpropane 4,4'-dioxyaceticacid (BPAc) onto chitin has been investigated at 298.15 K. The uptake of BPA and BPAc from aqueous solutions has been determined by UV-visible spectroscopy. Adsorption isothermal data was interpreted by the Freundlich, Langmuir, BET, D-R and F-H equations. The constants of these equations have been determined. The rate of kinetic processes of BPA and BPAc onto chitin was described by using three kinetics adsorption models. The pseudo-first-order model and intraparticle diffusion were the best choice among the kinetic models to describe the adsorption behaviour of BPA and BPAc onto chitin. (c) 2006 Elsevier B.V. All rights reserved.