The instability and low permeability of graphene oxide (GO) membranes in water treatment limit their wide application. In this study, we described the fabrication and testing of GO/MXene composite membranes modified by polyethylenimine (PEI). The unique structure of the composite membranes exhibited a synergistic effect in terms of water permeability and metal cation rejection, which varied with the mass ratio of GO and MXene. The composite membranes with a GO/MXene mass ratio of 1: 4 exhibited a higher water permeability (9.5 ± 0.4 L m⁻² h⁻¹ bar⁻¹). The PEI modified composite membrane had a rejection of over 70% for Ca²⁺ and Mg²⁺, which was about 7 times higher than that of the GO membranes. The removal mechanism of the PEI modified GO/MXene composite membrane on metal ions mainly involved steric effect and electrostatic effect. This kind of modified membrane has great potential in water softening.

氧化石墨烯（GO）膜在水处理中的不稳定性和低渗透性限制了它们的广泛应用。在这项研究中，我们描述了由聚乙烯亚胺 (PEI) 改性的 GO/MXene 复合膜的制造和测试。复合膜的独特结构在透水性和金属阳离子截留方面表现出协同效应，其随GO和MXene的质量比而变化。GO/MXene 质量比为 1:4 的复合膜表现出更高的透水性（9.5 ± 0.4 L m ^-2  h ^-1  bar ^-1）。PEI 改性复合膜对 Ca ²⁺和 Mg ²⁺的截留率超过 70%，比 GO 膜高约 7 倍。PEI修饰的GO/MXene复合膜对金属离子的去除机理主要涉及空间效应和静电效应。这种改性膜在软化水方面具有很大的潜力。