This study aims to demonstrate that zeolite has the potential to increase the efficiency of radiolysis treatment of aqueous organic pollutants by concentrating the pollutants into the zeolite’s pores. Using 2-chlorophenol (2-ClPh) as a model compound, we determined the high performance to be displayed by a mordenite-type zeolite (HMOR), which has a high silicon-to-aluminum ratio. HMOR adsorbed far more 2-ClPh than the other zeolites used in this study. We observed a significant increase in the radiolytic degradation efficiency of 2-ClPh in the presence of HMOR. Evidence shows that the high concentration of zeolite-adsorbed 2-ClPh facilitates radiation-induced degradation.