College of Urban and Rural Construction, Hebei Agricultural University, Baoding, People's Republic of China.
School of Environmental Science and Engineering, Tianjin University, Tianjin, People's Republic of China.
Environ Technol. 2024 May;45(13):2471-2485. doi: 10.1080/09593330.2023.2176262. Epub 2023 Feb 12.
Multilayered graphene oxide (GO) membranes are promising to be widely applied to purify water effectively. However, the performance of most membranes prepared at present is not ideal, which may be related to the pore diameter of the substrate (determining the real loading amount of GO) and the size of the GO nanosheets (determining the number of channels on the unit area), which has not been fully studied. In this study, a rotating dip-coating reactor were firstly developed to ensure the uniform deposition of reactants on the surface of the substrate. Then, the preparation method for the membrane was improved. Microfiltration membranes were used as the supporting substrate, polydopamine was deposited as the adhesive layer, ethylenediamine was used to restrict the layer spacing to strengthen the size exclusion effect, and positively charged polyethyleneimine (PEI) was used to strengthen the Donnan effect. Finally, the effects of the pore size of the substrate and the size of the GO nanosheets on the membrane performance were investigated. Compared with the substrates with a pore size of 0.22 μm in most literatures, substrates of 0.1 μm can retain more small GO (SGO) nanosheets, thereby improving the performance. The performance of the SGO membrane was much better than that of the large-sized GO membrane. With a water permeability of no less than 7.9 L/(m·h·bar), rejection rates for Pb and Cd of the SGO membrane could reach more than 97%. These findings are constructive to separate heavy metals from water effectively.
多层氧化石墨烯（GO）膜有望被广泛应用于有效净化水。然而，目前大多数制备的膜的性能并不理想，这可能与基底的孔径（决定 GO 的实际负载量）和 GO 纳米片的尺寸（决定单位面积上的通道数量）有关，而这些因素尚未得到充分研究。在本研究中，首先开发了旋转浸渍反应器以确保反应物均匀地沉积在基底表面上。然后，改进了膜的制备方法。使用微滤膜作为支撑基底，沉积聚多巴胺作为黏附层，使用乙二胺限制层间距以增强尺寸排阻效应，并使用带正电荷的聚乙烯亚胺（PEI）增强Donnan 效应。最后，研究了基底孔径和 GO 纳米片尺寸对膜性能的影响。与大多数文献中孔径为 0.22 μm 的基底相比，孔径为 0.1 μm 的基底可以保留更多的小尺寸 GO（SGO）纳米片，从而提高性能。SGO 膜的性能明显优于大尺寸 GO 膜。其水通量不低于 7.9 L/（m·h·bar），SGO 膜对 Pb 和 Cd 的截留率均达到 97%以上。这些发现有助于有效地从水中分离重金属。
