Graphene oxide membranes (GOMs) have great potentials in the high-performance desalination of salty wastewater. However, the low-selectivity and fouling issues are the main obstacles to practical implementation. Although compositing with TiO₂ nanoparticles alleviates such problems by regulating membrane structures and photodegrading surface organic filter cakes, the performance is still limited by the intrinsic aggregation feature and narrow UV response range. Here, we functionalize TiO₂ nanoparticles with polypyrrole (PPy) to improve their dispersibility and visible-light-driven photodegradation properties. The as-formed core-shell heterostructures (PPy@TiO₂) with a large dose are intercalated into GOM, resulting in a large water flux (436.93 Lm⁻²h⁻¹bar⁻¹) and selective positive dye/negative dye separation with a maximum salt permeation of 97%. Upon the reduction of the dosage, more than 99% of dyes are separated regardless of molecule weights and surface charge polarity although the average water flux is reduced to 5.83 Lm⁻²h⁻¹bar⁻¹ and the salt rejection rate is increased up to 24%. In addition, the composite membrane with low-dosed PPy@TiO₂ photodegrades MB completely within 2 h, while its water permeability and dye rejection performance are maintained after a 5 h filtration process. Our work provides a facile method to develop multi-functional 2D composite membranes with controllable and stable dye desalination performances.

氧化石墨烯膜（GOM）在含盐废水的高性能脱盐方面具有巨大的潜力。然而，低选择性和污染问题是实际实施的主要障碍。尽管与TiO ₂纳米粒子复合通过调节膜结构和光降解表面有机滤饼来缓解这些问题，但其性能仍受到固有聚集特征和窄紫外响应范围的限制。在这里，我们用聚吡咯 (PPy) 对TiO ₂纳米粒子进行功能化，以提高它们的分散性和可见光驱动的光降解性能。形成的大剂量核壳异质结构（PPy@TiO ₂）嵌入GOM中，导致大水通量（436.93 Lm^-2 h ^-1 bar ^-1 ) 和选择性阳性染料/阴性染料分离，最大盐渗透率为 97%。减少剂量后，尽管平均水通量降低至 5.83 Lm ^-2 h ^-1 bar ^-1且脱盐率提高至24%。此外，具有低剂量 PPy@TiO ₂的复合膜在 2 小时内完全光降解 MB，而在过滤过程 5 小时后仍保持其透水性和染料排斥性能。我们的工作为开发具有可控和稳定染料脱盐性能的多功能二维复合膜提供了一种简便的方法。