Cellulose acetate membranes functionalized with complex polyelectrolytes via layer-by-layer assembly for improved...

Area of Science:

• Materials Science
• Chemical Engineering
• Environmental Science

Background:

• Energy-efficient desalination is crucial but challenged by the flux-rejection trade-off in conventional membranes.
• Developing membranes for low-pressure operation with high performance remains a significant hurdle.

Purpose of the Study:

• To engineer novel cellulose acetate (CA)-based multilayer membranes for energy-efficient low-pressure desalination.
• To overcome the conventional trade-off between permeate flux and salt rejection.

Main Methods:

• Fabrication of CA-PEG membranes via phase inversion.
• Layer-by-layer (LbL) dip-coating of poly (allylamine hydrochloride) (PAH) and poly (acrylic acid) (PAA) onto CA-PEG membranes.
• Characterization of membrane structure, morphology, and desalination performance.

Main Results:

• Pristine CA-PEG membranes showed high flux but low salt rejection (~50%).
• PAH-PAA multilayer deposition reduced pore size and improved surface morphology.
• Optimized multilayer membranes (MM15) achieved ~97% salt rejection with high flux (178-230 L·m⁻²·h⁻¹) at 1.5-3 bar.
• Multilayer membranes demonstrated enhanced antifouling properties and reusability.
• Real seawater testing yielded up to 98% salt rejection.

Conclusions:

• CA-PEG/PAH-PAA multilayer membranes offer a promising solution for energy-efficient low-pressure desalination.
• These membranes exhibit superior permeability, selectivity, antifouling, and reusability.
• The LbL approach provides a viable strategy for fabricating high-performance desalination membranes.