Membrane/Oil Stripping of VOCs from Water in Hollow‐Fiber Contactor

Abstract

Separation of volatile organic contaminants from water using a microporous hollow‐fiber membrane/oil stripping system is evaluated. Countercurrent flow of water and oil on opposite sides of an air‐filled gas‐permeable membrane is used to concentrate the contaminants in the oil phase. The rate of mass transfer under varying conditions is measured and compared to existing full‐ and laboratory‐scale air‐stripping processes, to membrane‐extraction processes, and to predictions based on known empirical and theoretical correlations. The correlations can be used as the basis for system design and scale‐up. This process incorporates the advantages of other membrane‐stripping processes, such as a high surface area to volume ratio for transfer, and independent control of the separate liquid phases. It also overcomes several disadvantages of extraction and stripping processes. There is no contact between the liquid phases and thus no potential for cross‐contamination or emulsion formation. The membrane separation of phases prevents flow channeling and flooding present in air‐stripping towers. Finally, materials used in this process may be recovered and recycled, preventing further environmental contamination.