Competitive adsorption of sulfolane and thiolane on clay materials

Groundwater samples directly beneath a waste disposal site have been shown to contain a higher concentration of sulfolane and a relatively low concent ration of thiolane. The sulfolane is a source compound of thiolane, a reduc ed form of sulfolane. In subsequent analyses of groundwater samples, these compounds have been detected from all of the monitoring wells in the study area. Since these compounds are present together in an aquifer, a possible competition, that can happen in such a system, has been investigated. Thiol ane is a nonpolar heterocyclic organic compound whereas sulfolane is a weak ly acidic dipolar solvent. As expected, thiolane adsorbs more strongly onto clay than sulfolane in a single solute system. For regression of bisolute system using Matlab to obtain Q (maximum number of moles of solute adsorbed per unit weight of adsorbent), k(1) (constants related to the energy of ad sorption for sulfolane), and k(2) (constants related to the energy of adsor ption for thiolane), the k(1) value (sulfolane) is smaller than the k(2) va lue (thiolane) which reflects that thiolane is more strongly adsorbed than sulfolane. This is strongly consistent with the result obtained from single solute system. The Q for the sulfolane and combined data is the same that indicates that the sulfolane data is dominantly fitted because the concentr ations of sulfolane are much greater than those of thiolane in the experime nts. In combined data regression, the suppression of sulfolane adsorption o n clay was also observed by the presence of thiolane.