Dual-mode sorption model for single- and multisolute sorption onto organoclays

The dual-mode sorption model (DSM) was applied to the single-solute sorptio n of 2-chlorophenol, 3-cyanophenol, and 4-nitrophenol from water onto organ oclays. The three parameters contained in the DSM were determined for each solute by fitting to the single-solute isotherm data and subsequently utili zed in competitive multisolute sorptions. A systematic method to determine the parameters for each solute was also suggested. The ideal adsorbed solut ion theory (IAST) coupled with the single-solute DSM and the competitive du al-mode sorption model (CDSM) extended to describe multisolute sorption wer e used to predict multisolute sorption onto organoclays and compared with t he data to determine the predictive capabilities. The DSM was found to desc ribe well single-solute sorption from water onto organoclays. The predictio ns from the CDSM and the IAST based on the DSM, though rather poor for some solutes, were generally in agreement with the multisolute sorption data. H owever, we could not tell at this stage which of the two competitive models is better.