Chen Xiaoyi, Feng Zhihao, Gohil Janavi, Stafford Christopher M, Dai Ning, Huang Liang, Lin Haiqing
Department of Chemical and Biological Engineering, University at Buffalo, The State University of New York, Buffalo, NY 14260, USA.
Materials Science & Engineering Division, National Institute of Standards and Technology, MS 8542, 100 Bureau Drive, Gaithersburg, MD 20899, USA.
J Memb Sci. 2019;12. doi: ttps://doi.org/10.1021/acsami.9b19255.
Reduced-graphene oxide (r-GO) membranes with narrow channels exhibit salt rejections comparable to conventional nanofiltration (NF) membranes. However, their water permeances are much lower because of the high tortuosity for water permeation. Herein we report a facile solution-processable approach to create in-plane nanopores on GO nanosheets before reduction, dramatically decreasing the tortuosity and increasing water permeance while retaining the salt rejection. Specifically, holey GO (HGO) nanosheets were prepared via chemical etching using hydrogen peroxide, followed by the deposition on a porous support by vacuum filtration and then reduction via exposure to hydriodic acid solutions to generate the reduced HGO (r-HGO) membrane. The generation of nanopores increases the water permeance from 0.4 L m∙h∙bar (LMH/bar) to 6.6 LMH/bar with NaSO rejection greater than 98.5 %, and the membranes were robust under strong cross-flow shearing force for 36 h. Both water permeance and NaSO rejection of these r-HGO membranes for the first time simultaneously reach the level of the commercial polyamide-based NF membranes. Given their good antibacterial properties and resistance to aggressive chemical washing, the r-HGO membranes show the promise as next-generation NF membranes for desalination.
具有狭窄通道的还原氧化石墨烯（r-GO）膜表现出与传统纳滤（NF）膜相当的盐分截留率。然而，由于水渗透的曲折度高，它们的水渗透率要低得多。在此，我们报告了一种简便的可溶液加工方法，即在还原前在氧化石墨烯纳米片上制造面内纳米孔，显著降低曲折度并提高水渗透率，同时保持盐分截留率。具体而言，通过用过氧化氢进行化学蚀刻制备多孔氧化石墨烯（HGO）纳米片，然后通过真空过滤沉积在多孔支撑体上，再通过暴露于氢碘酸溶液进行还原，以生成还原的HGO（r-HGO）膜。纳米孔的产生使水渗透率从0.4 L m∙h∙bar（LMH/bar）提高到6.6 LMH/bar，对NaSO的截留率大于98.5%，并且这些膜在强错流剪切力下36小时内保持稳定。这些r-HGO膜的水渗透率和对NaSO的截留率首次同时达到了商业化聚酰胺基NF膜的水平。鉴于其良好的抗菌性能和对强化学清洗的耐受性，r-HGO膜有望成为下一代用于海水淡化的NF膜。
