Large-Area Clay Composite Membranes with Enhanced Permeability for Efficient Dye/Salt Separation

Area of Science:

• Materials Science
• Environmental Engineering
• Nanotechnology

Background:

• Textile wastewater discharge poses significant environmental risks due to high dye and salt content.
• Two-dimensional (2D) nanomaterial membranes show promise for dye/salt separation but suffer from limited processing capacity and ion permeability due to narrow spacing and tortuous channels.

Purpose of the Study:

• To develop a novel, high-performance membrane for efficient dye/salt separation from textile wastewater.
• To overcome the limitations of existing 2D nanomaterial membranes by creating enhanced transport pathways.

Main Methods:

• Fabrication of a sepiolite/vermiculite composite membrane using Meyer rod-coating with naturally occurring clays.
• Intercalation of sepiolite nanofibers within vermiculite nanosheets to create a looser, more permeable network.

Main Results:

• The optimized membrane (80% sepiolite) achieved a high flux of 78.12 LMH bar⁻¹.
• Demonstrated outstanding Congo Red dye rejection (~98.26%) and excellent dye/salt selectivity (10.41).
• Exhibited stable separation performance under acidic, alkaline, and prolonged operational conditions.

Conclusions:

• The sepiolite/vermiculite composite membrane offers a promising, cost-effective solution for efficient and environmentally friendly dye/salt separation.
• The simple fabrication method and use of low-cost materials enable large-scale production for industrial applications.
• This all-clay composite membrane presents a new strategy for tackling textile wastewater pollution.