Measurement and Prediction of Infinite Dilution Activity Coefficients for Separation of Harmful Organic Compound in Waste Water

研制了一种基于气提色谱法的无限稀释活度系数测量装置。该测量系统由氦气汽提气瓶、在温控水浴中用稻草制成的平衡池和用于成分测定的气相色谱仪组成。汽提气体通过流量控制器进入溶剂饱和室。电池里装满了溶剂。单元中的熔块玻璃尖端的孔径在4-8μm的范围内，例如G2玻璃过滤器。用磁力搅拌器搅拌溶液，以帮助混合和传质。平衡假设的一个有效检验是改变汽提气体的流量，看看我们在基于气提方法的基础上研制的装置对给定的体系是否获得了无限稀释活度系数的恒定值。测定了303.15 K下正己烷在十六烷溶剂中的无限稀释活度系数，该体系的文献值是非常准确的。本工作的无限稀释活度系数实验值为0.831。提出了基于基团贡献法的无限稀释活度系数的预测方法，如原始uniAC法、几种改进的uniAC法和ASOG法。通过在修正的泛函活度系数模型中引入混合型基团，提出了一种预测高度非理想水溶液中无限稀释活度系数的新方法。

Measurement apparatus of infinite dilution activity coefficients based on a gas stripping chromatography method have developed. The measurement system consists of a Helium gas cylinder for stripping gas, an equilibrium cell made by Pyrex grass in a temperature controlled water bath, and gas chromatograph for determination of composition. The stripping gas flows through the flow controller into the solvent saturation cell. The cell was filled with solvent. The fritted glass tip in the cell has a pore diameter in the range of 4-8 μm, e.g. the G2 glass filter. The solution is stirred with a magnetic stirrer to help mixing and mass transfer.An effective test of equilibrium assumption is to change the flow rate of stripping gas and see whether we get a constant value of infinite dilution activity coefficient for a given system using the developed apparatus based on a gas stripping method. The infinite dilution activity coefficient of Hexane in Hexadecane of solvent was measured at 303.15 K. The literature value of this system is very accurately known. The experimental value of infinite dilution activity coefficient is 0.831 in this work. The data is good agreement with the literature value and well reproducibility.The prediction methods of infinite dilution activity coefficient base on the group contribution method, e.g. original UNIFAC, several kind of modified UNIFAC, and ASOG have proposed. A new approach is proposed by introducing mixture type groups to the modified universal functional activity coefficient model for prediction of infinite dilution activity coefficients in highly nonideal aqueous solution.