On-demand separation of oil-water mixtures.

In this work, the first-ever membrane-based single unit operation that enables gravity driven, on-demand separation of various oil-water mixtures is developed. Using this methodology, the on-demand separation of free oil and water, oil-in-water emulsions, and water-in-oil emulsions is demonstrated, with ≥99.9% separation efficiency. A scaled-up apparatus to separate larger quantities (several liters) of oil-water emulsions is also developed.