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Quaternized graphene oxide modified PVA-QPEI membranes with excellent selectivity for alkali recovery through electrodialysis
Chemical Engineering Research and Design ( IF 3.7 ) Pub Date : 2019-11-25 , DOI: 10.1016/j.cherd.2019.11.026
Meng Li , Mengjie Sun , Wenya Liu , Xu Zhang , Cuiming Wu , Yonghui Wu

Composite anion exchanges membranes are prepared by incorporating quaternized graphene oxide (QGO) within poly(vinyl alcohol) (PVA) or the mixture of PVA and quaternized polyethyleneimine (QPEI), followed by cross-linking with formaldehyde. The PVA-QGO series of membranes have low ion exchange capacities (IECs) of 0.10–0.37 mmol/g and low water uptakes (WR) of 16.1%–22.0%, leading to high area resistances (>60 Ω cm2). The PVA-QPEI-QGO series of membranes show much lower area resistances of 2.47–6.04 Ω cm2, which is ascribed to the improved IECs (0.86–1.37 mmol/g) and WR (46.8%–71.4%). Both series of membranes show higher alkali resistance than commercial membrane AMV. Their weight losses are in the range of 0.5%–8.9% after immersion in 60 °C 2 mol/L NaOH alkaline solution for 32 days, while the value of AMV membrane is 19.2%. When utilized for electrodialysis (ED) application to recover NaOH from NaOH/Na2WO4 mixture, the prepared membranes exhibit high selectivity, as evidenced by the low leakage ratio of Na2WO4. The leakage ratio of the optimized composite membrane to WO42− is only 5.1%, while the leakage ratio of AMV membrane is up to 61.4%. To explore this reason, the composite membranes are selected for the ED separation of monovalent ions. The separation efficiency (S) of the optimized membrane is 83.9%, which is similar to the value of commercial anion selective membrane NEOSEPTA® ACS (88.7%), confirming further the selectivity of the composite membranes.



中文翻译:

季铵化氧化石墨烯修饰的PVA-QPEI膜具有优异的选择性,可通过电渗析回收碱

通过将季铵化氧化石墨烯(QGO)掺入聚乙烯醇(PVA)或PVA和季铵化聚乙烯亚胺(QPEI)的混合物中,然后与甲醛交联来制备复合阴离子交换膜。PVA-QGO系列膜的离子交换容量(IECs)为0.10–0.37 mmol / g,吸水率(W R)为16.1%–22.0%,导致较高的面积电阻(> 60Ωcm 2)。PVA-QPEI-QGO系列膜的面积电阻低得多,为2.47–6.04Ωcm 2,这归因于改进的IEC(0.86–1.37 mmol / g)和W R(46.8%–71.4%)。这两个系列的膜均显示出比市售膜AMV更高的耐碱性。在60°C 2 mol / L NaOH碱性溶液中浸泡32天后,它们的重量损失在0.5%–8.9%的范围内,而AMV膜的值为19.2%。当用于电渗析(ED)应用以从NaOH / Na 2 WO 4混合物中回收NaOH时,制得的膜表现出高选择性,如Na 2 WO 4的低泄漏率所证明。优化复合膜对WO 4 2-的泄漏率仅为5.1%,而AMV膜的泄漏率高达61.4%。为了探索这个原因,选择复合膜用于ED分离单价离子。优化膜的分离效率(S)为83.9%,与商业阴离子选择性膜NEOSEPTA®ACS的值(88.7%)相似,进一步证实了复合膜的选择性。

更新日期:2019-11-25
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