G-C₃N₄ Based Membrane Modified By MXene Derivatives For Water Environment Remediation

Multi-component pollutants are one of the challenges in the field of water remediation.The design of multifunctional and efficient separation membranes promises to solve this challenge.The emergence and development of two-dimensional（2D）graphitic phase carbon nitride（g-C₃N₄）has provided new ideas and research directions for material selection and design of high-performance membranes.However,the dense stacking of g-C₃N₄ nanosheets leads to reduce separation flux and shielding of a large number of photoactive sites.,which limits the wide application of g-C₃N₄ multifunctional separation membranes.In this paper,MXene derived materials were intercalated into g-C₃N₄ nanosheets.The perfect balance of high flux,high optoelectronic performance and multi-application functions of g-C₃N₄-based functional membranes were achieved by adjusting the compound ratio of g-C₃N₄ and MXene derivatives.The main research contents and conclusions include the following aspects:（1）The 2D/2D/0D g-C₃N₄/MXene@Ag（CNMA）composite membrane was constructed by vacuum-assisted self-assembly.It is shown that the introduction of Ag nanoparticles can optimize the interlayer structure of the membranes and enhance surface wettability.The separation flux of the composite membrane for 1,2-dichloroethane/water emulsions is up to6812.67±106 L m^-2 h^-1 bar^-1 with a maximum separation efficiency of 99.68%.Notably,the CNMA sepatation membrane has remarkable anti-fouling performance and maintains stable separation properties after 10 consecutive uses.In addition,MXene@Ag can optimize the energy band structure,improve the photoelectric properties,and achieve efficient removal of organic pollutants（dyes,antibiotics）.The efficiency of the membrane in degrading methylene blue dye is 98%.The CNMA functional composite membrane are suitable for water environment remediation under organic pollutant scenarios.This work meets the actual wastewater treatment requirements and achieves the optimization of g-C₃N₄ functional membrane.（2）An advanced 2D/3D g-C₃N₄/TiO₂@MnO₂ membrane was constructed by intercalating3D TiO₂@MnO₂ nanostructures into g-C₃N₄ nanosheets.The 3D flower-like nanostructure broadens the water molecule transport channels of the composite membrane.The membrane exhibites excellent separation of five oil/water emulsions,with a maximum flux of 3265.67±15.01 L m^-2 h^-1bar^-1 and a maximum efficiency of 99.69±0.45%for toluene emulsion（T/W）.Meanwhile,the TiO₂@MnO₂ acts as a good electron acceptor to trap photogenerated carriers and promote effective spatial separation of electron-hole（e^--h⁺）pairs.The membrane shows good degradation for three different pollutants,among which the degradation effect for methylene blue and malachite green were about 100%.The antibacterial efficiency against E.coli and S.aureus is also close to 100%.After 15 cycles,the membrane maintains its original separation and photocatalytic degradation capabilities with a flux recovery rate of over 98%,demonstrating excellent self-cleaning properties.The remarkable multifunctional and self-cleaning properties of the g-C₃N₄ composite membrane represent its potential value for complex wastewater treatment.