Modelling of the Competitive Adsorption Between Micropollutants and Background Organics.

点击翻译按钮获取中文摘要

IAS (Ideal Adsorbed Solution) theory was applied to a multi-component competitive adsorption on activated carbon. Numerical simulations were executed to the imaginary raw water containing solutes, the adsorption isotherm of which in their single-solute system is given by Freundlich equation. The result showed the essential difference between the adsorption isotherm of the total organics obtained by column tests and that obtained by batch tests. The simulations also showed that the batch adsorption isotherm changes when the raw water is diluted or concentrated. A predictive model was developed to describe the influence of dilution or concentration of raw water on the batch adsorption isotherm of the total organics. This model was successfully applied to the experimental batch adsorption isotherm of humic acid which is very typical background-organics in natural water, even though the concentration of humic acid was measured by surrogate parameters such as TOC and UV-adsorbance.Numerical simulations based on IAS theory also showed that the spreading pressure which specifies the adsorbed-phase can be correlated with the amount of the total organics adsorbed, and this correlation does not change when the raw water is diluted or concentrated and when the concentration of a certain component sligtly changes. Accordingly, the distribution ratio of a component between adsorbed-phase (activated carbon) and liquid-phase can be correlated with the amount of the total organics adsorbed. Based on the latter correlation, a simple but very practical model was developed to describe the competitive influence of background organics upon the adsorption of micropollutants onto activated carbon. This model was veryfied through the batch adsorption tests of paminobenzoic acid spiked into a river water which contains a moderate concentration of background organics.