均质硅橡胶膜用于含酚水溶液膜萃取传质过程

Mass transfer process of phenol aqueous solution through membrane extraction with non-porous silicone rubber membrane

研究了一种将均质硅橡胶膜与碱性萃取液相结合的新型膜萃取技术,用以处理含酚水溶液的传质机理与过程,并考察了该体系中两相流动状态、萃取液pH、料液浓度、两相压力和温度等因素对苯酚膜萃取传质速率的影响.基于液-膜-液串联传质阻力模型,通过实验测定苯酚的总传质系数Kov.研究表明:对于氢氧化钠-苯酚-水实验体系,传质由膜阻控制,Kov为3.72×10-7m/s;化学反应对苯酚传质速率的增强作用不显著;苯酚溶液浓度>8 000mg/L,Kov与其初始浓度无关;致密膜体系中两相压差的存在不利于传质的进行;Kov与运行温度呈直线关系.

A new membrane extraction technology with single tubular non- porous silicone rubber membrane and basic stripping solution was combined into membrane extraction used for treatment of phenol solution. Mass transfer mechanism and process of phenol through membrane were investigated. The effects of liquid flow status within the membrane module, stripping solution pH, phenol initial concentration, liquid pressure difference between opposite membrane sides, and system temperature on mass transfer coefficient were discussed. Based upon the resistance- in- series model, the overall mass transfer coefficient Kov across membrane was calculated. The experiment results indicated that the mass transfer enhancement by chemical reaction in the system for phenol was not remarkable, and Kov was 3.72 × 10^-7 m/s, which were dominated by membrane resistance in this process using silicone rubber. Kov was independent of phenol initial concentration （ 〉8 000 mg/L）. The presence of liquid pressure difference between opposite membrane sides went against permeability of phenol. Kov was in direct proportion to the temperature in this process.