Polyethylene glycol adsorption equilibrium on activated carbon

A series of polyethylene glycol polymers were sorbed on three activated carbons to determine (1) the molecular weight resulting in the greatest loading on the activated carbon, (2) the differences the activated carbon makes on this value, and (3) whether water reduces the amount of adsorption. From the adsorption cycle, the maximum loading occurred with polymers in the 1,000 to 8,000 molecular weight range for all three activated carbons. From the desorption cycle, the 20,000 molecular weight polymer loading was also at maximum loading for two activated carbons (a bituminous coal carbon, and a chemically activated coconut shell carbon). For the thermally activated coconut shell carbon, the 400 to 8,000 molecular weight polymers resulted in maximum loading for the desorption cycle. Substantial performance differences were not noted for the different activated carbons tested with most of the polymers. Preloading the activated carbon with pure polymer and performing desorption studies resulted in more loading on the carbon at equilibrium than from adsorption studies, with water adversely affected adsorption.