Separating Phenolic Compounds from Water By Adsorption on Surfactant-Modified Ion Exchange Resins

Various adsorption techniques can be used to remove phenolic compounds from wastewater. In this work, the adsorption of 4-chlorophenol (4CP) and phenol on surfactant-modified ion exchange resins were studied. Ion exchange resins were treated with oppositely-charge surfactant, and the modified resins were brought into contact with solutions containing one of the phenolic compounds. Adsorption isotherms were calculated from concentration measurements and then modeled with the Langmuir and Freundlich equations. The Freundlich isotherm model fits the data well for all systems that were studied. The Langmuir model works well for 4CP on the cetylpyridinium chloride (CPC) resins. Results are compared with those from other adsorption techniques including surfactant-modified clays. The adsorption capacity for 4CP on the CPC resins is less than that for activated carbon but comparable to other synthetic adsorbents and greater than some surfactant-modified clays. An increase in adsorbed surfactant on the aggregates not only gives rise to more 4CP adsorption, but the adsorption of 4CP per surfactant increases slightly. Adsorption is greater on the sodium dodecyl benzene sulphonate (SDBS) resin as compared with the CPC resins even though the amount of adsorbed surfactant is lower. Phenol adsorbs at smaller loadings as compared with 4CP for the same equilibrium solution concentration of solute, with larger adsorption capacity on SDBS resins.