Removal of Trace Organic Compounds in Water by Surface-modified Carbon Adsorbents

Abstract

The effects of the surface chemical structure and the pore structure of carbon adsorbents on adsorption of various organic compounds were studied in aqueous solutions. Pittsburgh activated carbon (Calgon Co.), and Electronic conductive carbon black (Lion Akzo Co.) that has a large surface area were used as carbon adsorbents.In order to investigate the effect of the surface chemical structure, the adsorbents were treated with HC1-HF, air, H2or HNO3.It was found that the adsorbed amounts increased with decreasing the surface acidity and the ash content of the adsorbents.In order to confirm the effect of the pore structure, the adsorbed amounts of organic compounds with different molecular weights on the adsorbents, those were deashed and treated with H2 to eliminate surface polar substances, were measured. When the occupied areas of adsorbates such as phenol and benzoic acid were small, the adsorbed amounts for the activated carbon with micropores were large.In contrast, in the case of the adsorption of large molecule such as polyvinyl alcohol, the adsorbed amount for the carbon black with mesopores was large.These results show that the adsorption character of organic compounds were closedly connected with the molecular size of adsorbates and the pore structure of adsorbents.