FIXED-BED ADSORPTION OF ACID DYES ONTO ACTIVATED CARBON

The context of the study here is the adsorption of acid dyes from wast ewater arising from a nylon carpet printing plant which currently rece ives no treatment. Since nylon is a particularly difficult fibre to dy e, acid dyes are required for successful coloration. However, their pr esence, in high concentrations, in aqueous effluent arising from the p lant can create major problems with respect to disposal. A treatment m ethod based on adsorption onto granular activated carbon (GAC F400) in a fixed column configuration is described and breakthrough data of th e dyes determined. The breakthrough data were correlated using a model based on liquid and pore diffusion with a good fit of experimental re sults obtained. Trends in the effective diffusivity used in the model correlated with other authors. A slight decrease in effective diffusiv ity was found with decrease in particle size and was attributed to int eractions between the relatively large molecular sized dye and the mic rospore structure found in granular activated carbon. (C) 1998 Elsevie r Science Ltd. All rights reserved.