Adsorption of phenolic compounds on Amberlite XAD-4 and its acetylated derivative MX-4

Amberlite XAD-4 polymeric resin was chemically modified with an acetyl grou p, which enables the resin to be used directly without a wetting process. T he modified resin was comparatively evaluated using four phenolic compounds , phenol, p-cresol, p-chlorophenol, and p-nitrophenol. The capacities of eq uilibrium adsorption for all four phenolic compounds from their aqueous sol utions increased around 20% on the acetylated resins within temperature ran ge of 283-323 K. Freundlich isotherm equations, as well as the relative ads orptive capacities and isosteric adsorption enthalpies for the four phenoli c compounds, indicate a physical and multiple-layer adsorption process on t he Amberlite XAD-4 resins either with or without the chemical modification. Mini-column adsorption studies showed that the breakthrough adsorption cap acity and the total adsorption capacity at designated conditions for all fo ur phenolic compounds also increased over 20% after chemical modification. (C) 2001 Elsevier Science BY. All rights reserved.