The influence of surface chemistry on activated carbon adsorption of 2-methylisoborneol from aqueous solution

An activated carbon with a relatively high oxygen content was heated at var ious temperatures in an argon atmosphere to produce a series of carbons wit h decreasing oxygen content. A second activated carbon with a relatively lo w oxygen content was treated with an ozone-oxygen mixture to produce a seri es of carbons with increasing oxygen content. In both cases, the pore size distribution and pore volume were unaffected by the treatment conditions. A dsorption isotherm and enthalpy of water displacement measurements were mad e for adsorption of 2-methylisoborneol (MIB) by these carbons in water. Bot h measurements show the importance of the oxygen content on the adsorption of MIB from aqueous solution. Increasing surface oxygen content at a consta nt pore volume leads to a decrease in both the amount adsorbed and the enth alpy of adsorption. To test the role of the solvent in this adsorption proc ess, a relatively non-polar solvent, dichloromethane (DCM), was used to mak e adsorption measurements. Adsorption isotherms show that the amount of MIB adsorbed from DCM solution is independent of the oxygen content. These res ults indicate that the solvent plays an important role in the control of th e adsorption from solution of a sparingly soluble solute. (C) 2001 Elsevier Science B.V. All rights reserved.