SORPTION OF TOXIC ORGANIC-COMPOUNDS ON WASTE-WATER SOLIDS - MECHANISM AND MODELING

It is proposed that sorption is a combination of two fundamentally different processes: adsorption and partitioning. A sorption model was developed for both single-component and multicomponent systems. The model was tested using single-component experimental isotherm data of eight toxic organic compounds. Partitioning dominates the sorption process for compounds with high sorbability or high octanol-water partition coefficient, K(ow) Binary sorption data were compared with the present model. The proposed model fitted experimental data well It was found that K(ow) could be used to assess the competition effect in a multicomponent system. The competition is negligible when Kw is larger than 1000. When K(ow) is smaller than 500, there is a significant competition effect. In very dilute solutions, the effect of the presence of a competing species can be ignored.