Free-Standing Amphiphilic Organic Membrane toward Ultrafast and Efficient Demulsification.

Area of Science:

• Materials Science
• Chemical Engineering
• Environmental Science

Background:

• Conventional oil-water separation methods like absorption and flocculation are energy-intensive and inefficient.
• Membrane-based separation is promising but faces challenges with oil and surfactant fouling.
• Surfactant-stabilized water-in-oil emulsions require advanced separation solutions.

Purpose of the Study:

• To design and fabricate a novel free-standing, amphiphilic organic membrane (AOM-1) for efficient demulsification of surfactant-stabilized water-in-oil emulsions.
• To investigate the antifouling properties and separation performance of AOM-1 compared to a hydrophobic organic membrane (HOM-1).
• To elucidate the interaction mechanisms between the membrane and surfactants using molecular dynamics simulations.

Main Methods:

• Interfacial fabrication of an amphiphilic organic membrane (AOM-1) with a hydrophilic polyethylene glycol (PEG)-inspired core and hydrophobic alkyl chains.
• Performance evaluation of AOM-1 and HOM-1 in terms of flow rate, separation capacity, and recyclability.
• Molecular dynamics simulations to analyze the interactions between surfactants and membrane surfaces.

Main Results:

• AOM-1 demonstrated a high steady flow rate (≈2550 L·m⁻²·h⁻¹) and separation capacity (≈7.1 × 10³ L·m⁻²), significantly outperforming HOM-1 (≈1.6 × 10³ L·m⁻²).
• AOM-1 exhibited excellent recyclability over five cycles, indicating robust antifouling properties.
• Molecular dynamics simulations revealed that strong polar-polar interactions in AOM-1 prevent pore blockage by surfactants, unlike the nonpolar-nonpolar interactions in HOM-1.

Conclusions:

• The designed amphiphilic organic membrane (AOM-1) effectively addresses the fouling issues in membrane-based oil-water separation.
• AOM-1 offers superior performance, including high separation capacity and recyclability, making it a viable alternative to conventional methods.
• The study highlights the potential of amphiphilic membranes for large-scale, energy-efficient demulsification of challenging emulsions.