Insight into the efficient co-removal of Cr(VI) and Cr(III) by positively charged UiO-66-NH2 decorated ultrafiltration membrane
Insight into the efficient co-removal of Cr(VI) and Cr(III) by positively charged UiO-66-NH2 decorated ultrafiltration membrane
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DOI：
10.1016/j.cej.2020.126546
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发表时间：
2021-01
影响因子：
15.1
通讯作者：
Zhang Yanhong;Xiaoming Xu;C. Yue;Song-Lin Li;Y. Lv;Fuqiang Liu;Aimin Li
中科院分区：
文献类型：
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作者：
Zhang Yanhong;Xiaoming Xu;C. Yue;Song-Lin Li;Y. Lv;Fuqiang Liu;Aimin Li
为了有效地去除废水中的总铬，通过沉积UIO-66-NH_2，然后与以聚偏氟乙烯(PVDF)为基础的聚乙烯亚胺(PEI)进行交联，成功地制备了一种新型复合膜(PEI/MOF@PVDF)。UIO-66-NH_2主要固定在膜表面和指状孔上，降低了膜的亲水性，提高了膜的表面正电荷，而交联型PEI不仅充分弥补了这一不足，而且提高了膜的稳定性。PEI/MOF@PVDF具有较高的纯水通量，达到561g L/(m2.h)，而牛血清白蛋白污染膜的水通量可恢复到96.13%。这是首次研究新型带正电UIO-66-NH_2修饰超滤膜(PEI/MOF@PVDF)对铬(VI)和铬(III)的高效协同去除。有趣的是，在有效处理量为2322.23×L/m2时，出水铬(VI)浓度突破，主要是通过静电吸引和正孔带电。由于Donnan对阳极膜的影响，出水中的铬(III)浓度稳定。EDS图谱表明，铬(VI)因其高电势和高浓度的UIO66-NH2优先吸附在膜孔内，而铬(III)主要被排斥在正极表面。此外，由于PEI的成功交联，PEI/MOF@PVDF膜对UIO-66-NH_2的泄漏可以忽略不计，并且膜可以很容易地再生和重复使用。因此，新开发的复合膜在处理真实废水时显示出对铬(VI)和铬(III)的有效共去除的潜力。
To effectively remove total Cr from wastewater, a novel composite membrane (PEI/MOF@PVDF) was successfully prepared by depositing UiO-66-NH2and subsequently cross-linking with polyethylene imine (PEI) based on polyvinylidene fluoride (PVDF). UiO-66-NH2was mainly immobilized on the membrane surface and finger-like pore, which reduced the hydrophilicity and improve the surface positive charge, while the cross-linked PEI not only sufficiently covered this shortage but also enhanced the stability of membrane. PEI/MOF@PVDF owned such a high pure water flux as 561 L/(m2·h), meanwhile the water flux of BSA-contaminated membrane could be restored to 96.13%. This is the first work focusing on the efficient co-removal of both Cr(VI) and Cr(III) with the novel positively charged UiO-66-NH2decorated ultrafiltration membrane (PEI/MOF@PVDF). Interestingly, the effluent concentration of Cr(VI) was broke through at effective treatment volume of 2322.23 L/m2which was mainly charged by electrostatic attraction with the positive pores. And the effluent concentration of Cr(III) was consistently stable because of Donnan effect on the positive membrane. The EDS mapping revealed that Cr(VI) was preferentially adsorbed in the membrane pores for their high potential with highly concentrated UiO-66-NH2, while Cr(III) was mainly rejected on the positive surface. Moreover, PEI/MOF@PVDF showed negligible leakage of UiO-66-NH2owing to the successful cross-link of PEI and the membrane can be easily regenerated and reused. Thus, the newly-developed composite membrane showed a promising potential for the efficient co-removal toward both Cr(VI) and Cr(III) in treating authentic wastewater.