Membrane extraction is a new separation technique combining membrane separation with liquid-liquid extraction. Hie membrane extraction technique used to dispose a large quantity of dilute acetic acid generated in furfural production was introduced. Complex extractant was composed of complexant, thinner and conditioner in a certain proportion. The partition coefficient of acetic acid in the extractant and aqueous phase was tested. In countercurrent flow pattern, the influences of extraction efficiency of acetic acid on the velocity of the two phases, initial concentration of acetic acid, contact time and membrane modules in series were studied by using iPP hollow fiber membrane self-prepared by thermally induced phase separation method and that provided by Membrana GmbH, respectively. The results show that the partition coefficient is 4.350 when the concentration of acetic acid is below 0.42 mol/L; the extraction rate of the single-stage module can reach 60. 5% when initial concentration of acetic acid is 0. 104 mol/L; organic phase velocity is 0.000 16 m/s, aqueous phase velocity is 0.000 28 m/s, and contact time is about 30 s. Therefore, membrane extraction applied in the treatment of dilute acetic acid wastewater has an obvious advantage.%膜萃取是膜分离与液液萃取相结合的一种新型分离技术,文中采用膜萃取技术处理糠醛生产过程中产生的大量低浓度醋酸废水.络合萃取剂选用了一定比例的络合剂、稀释剂和调节剂配制成；测定了低浓度下醋酸在萃取相和水相中的分配系数；分别用实验室热致相法制备的聚丙烯(iPP)中空纤维膜和德国Membrana商用iPP中空纤维膜,以醋酸萃取率为指标,在逆流方式下对二相流速、初始醋酸浓度、接触时间和膜器串联的影响进行了考察.结果表明:在醋酸浓度低于0.42 mol/L时,分配系数近似于常数4.350；单个膜组件下,在初始醋酸浓度为0.104 mol/L,有机相流速为0.000 16 m/s,水相流速为0.000 28 m/s,接触时间大约30 s时,醋酸萃取效率达到60.5％,说明膜萃取技术应用于稀醋酸废水处理具有明显的优势.
展开▼
