Additive-optimized micro-structure in cellulose acetate butyrate-based reverse osmosis membrane for desalination

Area of Science:

• Materials Science
• Chemical Engineering
• Environmental Science

Background:

• High water flux in cellulose acetate butyrate (CAB)-based reverse osmosis (RO) membranes is crucial for desalination and mitigating freshwater shortages.
• Current CAB-based RO membranes face limitations in achieving optimal performance.

Purpose of the Study:

• To develop an optimized formulation for CAB-based RO membranes to enhance water flux and salt rejection.
• To investigate the correlation between membrane microstructure and desalination performance.

Main Methods:

• An "optimization of formulation-induced structure" strategy was employed using acetone, triethyl phosphate, glycerin, and n-propanol.
• The viscosity of the casting solution was optimized to 995.52 mPa·s.
• Membrane performance was evaluated based on salt rejection, permeate flux, and separation efficiency for various contaminants and conditions.

Main Results:

• Achieved state-of-the-art salt rejection of 97.1% and permeate flux of 8.73 L·m⁻²·h⁻¹.
• Demonstrated high separation performance for Rhodamine B, Congo red, NaCl, and MgCl₂ under varying concentrations and durations.
• Exhibited resistance to feed pressure changes and a low surface roughness (Ra = 16.3) with good hydrophilicity.

Conclusions:

• The optimized formulation and resulting "jellyfish"-like microstructure significantly improve CAB-based RO membrane performance.
• The study establishes a correlation between additive-optimized microstructure and enhanced desalination capabilities.
• This approach offers a promising strategy for developing advanced CAB-based RO membranes for water treatment.