Abstract |
It has been shown by experiment that acidic surface oxides on active carbon can profoundly influence the sorption of various pollutant-type molecules from aqueous solution. Not only is the equilibrium sorption capacity of the carbon affected but the rate of sorption is also changed. However, these changes are reversible, for removal of the acidic surface oxides can restore the carbon to its original sorption capacity or beyond. In the cases of sorption of phenol, nitrobenzene, sodium benzenesulfonate and dextrose, surface oxides reduced the sorption capacity of the carbon as well as the speed of sorption. In the case of urea sorption the sorption capacity of the carbon was increased by the presence of acidic surface oxides. It appears that the influence of these surface oxides depends on the relative strength of their interactions with both the water solvent and the solute to be adsorbed. (Author) |