A study was made of the adsorption characteristics of triethyl phosphate (TEP), dimethyl phosphate (DMP), and orthophosphate (OP), from aqueous solution onto activated charcoal cloth (ACC). The isotherms obtained were of a Langmuir type and, at neutral pH, and 293°K, the equilibrium adsorption capacities were 2430, 107, and 44.6 μmol g −1 from TEP, DMP, and OP solutions, respectively. DMP and OP adsorption was found to be strongly pH dependent. It is suggested that this dependence arises because of a combination of their p K values and the charge on the charcoal cloth surface in aqueous media. The latter was established by measurement of the electrophoretic mobility as a function of pH. No pH effect was evident in the TEP adsorption. Prior to reaching equilibrium it was shown that adsorption was proportional to ( time) 1 2 indicating a dependence on intrafibril (particle) diffusion.