Sorption of some textile dyes by beech wood sawdust

The purpose of this paper is to establish the experimental conditions for removal of several textile dyes from aqueous solutions by sorption on beech wood sawdust, an industrial waste lignocellulosic product. From the six dyes tested, the sorbent shows preference for three dyes: Direct Brown, Direct Brown 2 and Basic Blue 86. Sorption of dyes on the beech wood sawdust is dependent on the nature of dye, pH, dyes concentration, contact time, and amount of sorbent. By comparative kinetic studies, the rate of sorption was found to conform with good correlation to pseudo-second-order kinetics. The parameters that characterize the sorption were determined on the basis of Langmuir isotherms. The preference of beech sawdust for dyes increases as follows: Basic Blue 86 < Direct Brown 2 < Direct Brown. The maximum capacity of sorption of the commercial dye (of similar to 60% purity) was found to be 526.3 mgg(-1) for Direct Brown. (C) 2008 Elsevier B.V. All rights reserved.