Preparation of carbonaceous adsorbents for removal of chloroform from drinking water

Microporous carbons for use as adsorbents in removing chloroform from drink ing water were prepared by activating charcoals made from the following nat ural raw materials: evergreen oak (Q. phillyraeoides), bamboo (P. pubescens ), coconut shell (C. nucifera), and Japanese cedar (C. japonica), and from dehydrochlorinated vinylidene film. Chloroform adsorption was found to be e nhanced by increase in the specific surface area of the microporous carbon, but suppressed by enlargement of micropore-size. This suppression is due t o a decrease in the interaction, governed by London dispersion force, betwe en the chloroform molecules and the pure walls of the microporous carbon. C arbon with iodine adsorption capacity of around 760 mg g(-1) demonstrated t he greatest chloroform adsorption regardless of the raw material used. In o rder of chloroform adsorption amount, the materials ranked as follows: viny lidene film>Japanese cedar>coconut shell=evergreen oak> bamboo. The carbon produced by 30 min dehydrochlorination of vinylidene film and that produced by 50 min steam activation of Japanese cedar charcoal demonstrated adsorpt ion capacities several times higher than that or commercial activated carbo n. (C) 2001 Elsevier Science Ltd. All rights reserved.