正渗透膜污染的影响因素及清洗效果研究

为研究正渗透(FO)浓缩过程中的膜通量衰减规律,本文以牛血清白蛋白(BSA)为特征污染物,研究了正渗透过程中原料液的离子强度及BSA浓度、膜方位等参数不同时FO膜的污染规律,以提高膜通量和截留率为目标,对驱动液的种类、浓度,料液流速进行了优化,并优化了适宜的膜清洗方案.结果表明:原料液中离子强度越大,FO膜的初始通量越...

Research on Influencing Factors and Cleaning Effect of Forward Osmosis Membrane Fouling

In order to study the attenuation regularity of membrane flux in the process of forward osmosis (FO) concentration, the fouling rule of FO membrane affected by different parameters including ionic strength, BSA concentration in the feed and membrane orientation was studied with Bovine serum albumin (BSA) as the primary typical pollutants. In order to improve the membrane flux and rejection rate, the type and concentration of draw solution and the flow rate of feed solution were optimized and the appropriate membrane cleaning scheme was optimized. The results showed that the initial flux of FO membrane decreased with the increasing of ionic strength in feed solution, but the flux of FO membrane with BSA solution containing salt ions was higher than that of pure BSA solution as the running time went on. The lower the concentration of BSA, the lighter the membrane fouling was, and the water flux in FO mode (13.82±3.2 L/m2·h) was higher than that in PRO mode (5.08±2.1 L/m2·h), which indicated that FO mode should be adopted for concentration. Under the optimal operating conditions, the 1.5 mol/L NaCl as the draw solution and the flow rate of both feed and draw solution controlled at 2.89 m/s, FO flux was 11.23±2.13 L/m2·h, BSA retention rate was 97.83%, and reverse solute flux Js was 0.14 mol/m2·h. After the fouled membrane was immersed in 0.05% NaOH for 4 min, the flux recovery rate reached 98.39% and the flux recovery rate was still exceed 98% after reusing and cleaning many times, which indicated that the membrane had good cleaning resistance. This study would provide a certain technical reference for protein recovery from food materials.