Study On The Preparation And Extraction Of Cu²⁺ From Aqueous Solution Of PVDF-woven Tubal Hollow Fiber

Hollow fiber composite membrane extraction had a very unique advantages interms of metal ion separation and extraction as a new separation technology, comparedwith the usual liquid-liquid extraction process, membrane extraction can provide greatersurface area and mass, higher extraction efficiency. Currently, less hollow fibercomposite membrane for extraction of metal ions was investigated, and its cost was low,so there was a very large research value.In this study, PVDF-woven tubal hollow fiber composite membrane were preparedusing PET woven tubal for support strengthen layer, PVDF、PVA、DMAC、LiCl foruniform dope liquid,through the coating and phase separation technology.And investedextraction of Cu2+from aqueous solution. Analyzed the average pore diameter,porosity.By using scanning electron microscopy (SEM) analysis the membranestructure.Next selected the best performance of the composite membrane into a glasstube.and use membrane contactor as the experimental apparatus for the extraction ofcopper ions, using D2EHPA organic as extractant and kerosene as diluent, The effect ofsolution pH, temperature and other process conditions on the mass transfer performanceand extraction rate were studied. And investigated the changes of extraction rate of Cu2in different PVA concentration, Thereby laying the foundation for the study ofhydrophilic membrane..The main conclusions of this study are as follows: （1）Coating layer covered the braided tube surface closly. Compared with thethickness of the braided tube, composite membrane thickness of coating layersignificantly smaller. Only about20%.The composite membrane coating was a thinlayer of porous structure,thus decreasing casting solution, and can reduce the cost ofmembrane preparation.（2）PVDF-woven tubal hollow fiber composite membrane were prepared usingPET woven tubal for support layer, PVDF、PVA、DMAC、LiCl for uniform dopeliquid,through the coating and phase separation technology. The results showed that:the porosity of composite membrane was strongly influenced by woven tube parametersand PVA concentration, when the braided tube diameter increased, the porosity ofcomposite membrane decreased, and increased with the increasing of the mesh, whenthe outer diameter was1.25mm, mesh was40, the porosity achieved63.2%. With thecasting of liquid PVA concentration increased, microporous composite membranesurface gradually into a big hole. When the concentration of PVA was4%, themorphology of composite membrane structure more reasonable, the porositywas60.4%.（3）Self-developed composite membrane with the membrane contactor wasengaged to study the pH, temperature, flow rate of the water phase and the organicsolution phase flow rate, concentration of extractant and other process conditions on theextraction rate. The results showed: when the influent concentration100mg/L, pH=4.89, a temperature of37℃, the water phase flow rate10mL/min, the organic phaseflow rate18mL/min, PVA concentration of PVDF-braided tube hollow fibercomposite membrane4wt%, the extraction rate was78%.