盐酸溶液通过交替沉积的聚电解质自组装多层膜的渗透实验研究

Experimental Study on Hydrochloride Acid Permeation across Layer-by-Layer Self-assembled Polyelectrolyte Membranes

采用交替沉积的自组装方法在多孔支撑体上制备了PAH/PSS、PVA/PVS、PDADMAC/PSS三种聚电解质超薄膜,研究了盐酸溶液在浓度梯度下通过所制备膜的渗透行为。实验发现在一定条件下,盐酸的渗透通量随盐酸浓度的增加而增加、与聚电解质自组装膜的组装层数n和膜材料的电荷密度ρc分别成如下的关系:J=5.221+11.755e-n/15.279及J=1.624+102.851e-ρc/0.028(J的单位为:10-10mol?cm?2?s?1)。研究表明:膜的组装层数越多(厚度越大)或膜材料的电荷密度越高时,盐酸的渗透通量越小;通过控制膜的组装层数(厚度)或合成不同电荷密度的膜,可有效地控制膜的渗透速率。

The polyelectrolyte multilayer PAH/PSS, PVA/PVS, PDADMAC/PSS membranes were prepared by alternating layer-by-layer deposition of cationic and anionic polyelectrolyte on the porous PAN/PET supporting membranes, and the transport behavior of hydrochloride acid across the prepared membranes was investigated under the different concentration gradients. It is found that the permeation flux (J) of hydrochloride acid increases with the increase of the feed concentration of hydrochloride acid, and depends on the number of dipping cycles (n) and the charge density (φc) of polyelectrolyte membrane material, which could be expressed respectively as follows: J=5.221+11.755 e-n/15.279 and J=1.624+102.851 e-φc/0.028 (where J is in the unit of 10-10 mol&middotcm-2&middots-1). Experiments show that the permeation flux of membrane decreases with the increase of the membrane thickness and the charge density of the polyelectrolyte material, which indicates that by controlling the number of dipping cycles in membrane preparation or using various polyelectrolyte materials with different charge density to prepare the membrane, the permeation rate of the membranes can be controlled. The polyelectrolyte multilayer membranes may be useful for separation of acids and control of acidity in some reaction systems.