正渗透中驱动溶质反渗模型的建立与实验验证

Modeling for reverse permeation process in forwad osmosis and its experimental vertification

正渗透过程能够有效运行的一个前提条件是要求驱动溶质反向扩散的通量非常小。为了深入了解正渗透过程中驱动溶质反渗对膜分离过程的影响,以现有的浓差极化模型为基础,建立正渗透过程不同操作模式下驱动溶质的反渗通量以及膜通量的数学模型。为证明模型的准确性,以Na Cl为驱动液做一组序批式实验,测出不同初始渗透压下的水通量和反渗通量,将实验值与模型预测值比较,发现模型的预测结果与实验结果高度吻合。

The effective operation of forward osmosis systems requires that the reverse flux of draw solute from the draw solution into the feed solution be minimized. To better understand the effect of reverse draw solute permeation in forward osmosis membrane separation process,a model which describes the reverse permeation of draw solution in different operation modes was developed based on previous studies of concentration polarization.A set of sequencing batch experiments were conducted to validate the model predictions with a highly soluble salt( Na Cl) as a draw solution. Reverse draw solute permeation and water flux at different initial osmotic pressures were measured,and strong agreement between the model predictions and experimental results was observed.