Self-cleaning GO/g-C₃N₄/ZnO composite membrane for dye nanofiltration

Area of Science:

• Materials Science and Engineering
• Environmental Science and Technology
• Nanotechnology

Background:

• Membrane-based water purification is effective but hindered by membrane fouling.
• Developing self-cleaning membranes is crucial for sustained performance and efficiency.
• Graphene oxide (GO), graphitic carbon nitride (g-C3N4), and zinc oxide (ZnO) offer unique properties for advanced membranes.

Purpose of the Study:

• To develop a self-cleaning GO/g-C3N4/ZnO composite membrane with enhanced fouling resistance.
• To investigate the structural stability and photocatalytic properties of the composite for water purification.
• To evaluate the separation efficiency, permeability, and long-term stability of the developed membrane.

Main Methods:

• Synthesis of GO via modified Hummer method and g-C3N4 via calcination.
• Fabrication of composite membranes using vacuum filtration on nylon support with varying ZnO concentrations and maleic anhydride cross-linker.
• Characterization using FTIR, XRD, UV-Vis DRS, PL, SEM-EDX; performance evaluation via naphthol blue black filtration and cross-flow filtration tests.

Main Results:

• Successful synthesis of GO/g-C3N4/ZnO composite with homogeneous elemental distribution confirmed.
• High separation efficiency up to 99.9% for naphthol blue black.
• Optimal membrane (GO/g-C3N4/15.ZnO) maintained 93% rejection after four cycles; stable rejection (~99%) over 20h under UV irradiation demonstrated self-cleaning capability.

Conclusions:

• The GO/g-C3N4/ZnO composite membrane exhibits excellent fouling resistance and self-cleaning properties.
• The membrane demonstrates high separation efficiency and stable performance, making it suitable for water purification.
• This composite membrane is a promising candidate for durable and efficient self-cleaning water filtration applications.