Multifunctional Switchable Nanocoated Membranes for Efficient Integrated Purification of Oil/Water Emulsions

Area of Science:

• Materials Science
• Environmental Science
• Nanotechnology

Background:

• Developing surfaces with under-liquid dual superlyophobicity is challenging due to thermodynamic contradictions.
• Existing antifouling surfaces often have limited effectiveness, restricting practical applications.

Purpose of the Study:

• To create a novel hybrid membrane with enhanced under-liquid dual superlyophobicity for wastewater treatment.
• To investigate the material's performance in separating emulsified oily wastewater and its self-cleaning capabilities.

Main Methods:

• In situ growth of a hybrid zeolitic imidazolate framework-8 and zinc oxide nanorod on a porous poly(vinylidene fluoride) membrane (ZIF-8@ZnO-PPVDF).
• Testing the membrane's mechanical strength, reversible under-liquid dual superlyophobicity, and photocatalytic self-cleaning property.
• Evaluating its capacity for separating oil-in-water (O/W) and water-in-oil (W/O) emulsions using a "bait-hook-eliminate" method.

Main Results:

• The ZIF-8@ZnO-PPVDF membrane demonstrated superior mechanical strength and reversible under-liquid dual superlyophobicity.
• Achieved ultrahigh fluxes (>600 L m⁻² h⁻¹) and efficiencies (>99%) for separating both O/W and W/O emulsions.
• Exhibited effective photocatalytic self-cleaning and complete, non-destructive regeneration via visible-light irradiation.

Conclusions:

• The novel ZIF-8@ZnO-PPVDF membrane offers a promising solution for self-cleaning, switchable barrier applications in rapid filtration of emulsified oily wastewater.
• This study presents a new approach for preparing under-liquid dual superlyophobic, revivable membranes for diverse applications.