Attachment of benzo-crown ethers onto activated carbon cloth to enhance the removal of chromium, cobalt and nickel ions from aqueous solutions by adsorption.

This work consists of two stages. In the first stage, the adsorption of some monobenzo- and dibenzo-crown ethers onto activated carbon cloth (ACC) was investigated. Adsorption isotherm data were derived at 30 degrees C. Then the ACC surface was modified by saturating it with crown ethers. In the second stage, the adsorption of three metal ions, Cr(III), Co(II) and Ni(II), onto both the ACC and the ACC modified with crown ethers was investigated. The enhancement of adsorption of the ACC upon modification with crown ethers was examined for the three ions. The effects of the type and cavity size of crown ethers, the size and form of the ions on the extent of adsorption were discussed in terms of interactions of adsorbate species with the ACC surface. All the isotherm data were treated according to Langmuir and Freundlich models. Generally, Freundlich model was found to represent the experimental isotherm data better than Langmuir model.