三维网络萃取膜的制备及传质效率研究

Preparation and mass transfer efficiency of three-dimensional network extraction membrane

以亲水聚四氟乙烯(PTFE)膜为支撑体、以乙烯基三乙氧基硅烷(VTES)为偶联剂,利用乙烯基封端聚二甲基硅氧烷(PDMS)和聚甲基氢硅氧烷(PMHS)锁闭萃取剂磷酸二异辛酯(D2EHPA),制备三维网络萃取膜(3D-NEM),并将其用于重金属离子废水中镍元素的萃取分离。研究结果显示60℃、15min的处理条件可以不破坏原支撑体结构并在其表面成功引入羟基,使构建的三维网络复合层锚定在改性后的支撑体表面。在料液相Ni^(2+)浓度150mg/L、萃取剂含量37%(质量)的条件下3D-NEM的6h平均传质通量达最高值1560.28mg∙m^(−2)∙h^(-1)。相互交联的三维网格结构有效地阻止了萃取剂流失,6h运行平均通量衰减率仅有31.91%。与传统支撑液膜相比,本研究制备的3DNEM在亲水膜表面成功锚定超薄萃取功能层,体现出降低传质阻力与提升运行稳定性的双重优势。

The three-dimensional network extracting membrane(3D-NEM)was prepared by using hydrophilic polytetrafluoroethylene(PTFE)membrane as the support,vinyl triethoxysilane(VTES)as coupling agent,vinyl terminated polydimethylsiloxane(PDMS)and polymethylhydrosiloxane(PMHS)as grid locking extractant bis(2-ethychexyl)phosphate(D2EHPA).The designed 3D-NEM was tested for the extraction of nickel from heavy metal ion wastewater.The results showed that the surface treatment at 60℃for 15 min would not destroy the membrane structure but only introduced hydroxyl groups on its surface successfully.Further,the 3D network composite layer could be anchored on the modified support surface.To treat the feed of 150 mg/L Ni^(2+),the 6 h average mass transfer flux of 3D-NEM prepared with 37%(mass)extractant content reached the highest value of 1560.28 mg∙m−2∙h^(-1).The cross-linked 3D grid structure effectively prevented the loss of extractants,and the flux attenuation was only 31.91%after 6 h of operation.Compared with the traditional support liquid membrane(SLM),the 3D-NEM prepared in this study anchored the ultra-thin extraction functional layer on the hydrophilic membrane surface,presenting dual advantages of reducing mass transfer resistance and improving operation stability.