<p>The authors have presented a method to prepare a hydrophobic aluminum-oxide-based catalyst of isotopic exchange of oxygen between carbon dioxide and water. It has been shown that after the surface hydrophobization of granulated aluminum oxide, despite the decline in its catalytic activity, the obtained catalyst remains active in the reaction of catalytic isotope exchange. Mass-exchange characteristics of isotope exchange have been determined between the carbon dioxide and water in a countercurrent column filled with the mixture of the hydrophobic catalyst and the hydrophilic packing. It has been established that adding the catalyst to the packed bed leads to a significant improvement of mass exchange.</p>