Numerous organic contaminants are increasingly found in U.S. waterways; some of these pose health hazards to plants, animals, or humans. Removal of some organics by adsorption onto activated carbons is a standard technique used to remediate some waters, depending on the organics involved, and the volume of contaminated water. However, some organic compounds are resilient to removal by some carbons for a variety of reasons. In this study, the molecular interactions of 1,4-dioxane and water with various functional groups known to exist on some activated carbon surfaces (carbonyls, carboxyls, and hydroxyls) were investigated. Additionally, binding energies and Henry's Law constants were determined for 1,1-dichloroethylene (1,1-DCE) and perfluorooctanoic (PFOA) acid in all-silica molecular sieve zeolites to predict adsorption affinities in an attempt to design suitable adsorbents for their removal. It is shown that these relatively less demanding calculations are sufficient to reveal favorable and unfavorable sorbate/sorbent combinations, which can ultimately lead to rational selection of remediation systems.