Journal of Membrane Science, Vol.171, No.1, 105-117, 2000
Cross-flow ultrafiltration of an aqueous polymer foam solution produced by gas sparging
The potential use of cross-flow ultrafiltration membranes to filter and break a foam solution of an aqueous polymer is investigated. A solution made of 300 kDa polyvinylpyrrolidone (PVP) dissolved in water was introduced into a tubular ultrafiltration membrane module having a 100 kDa MW cut off. The polymer has the property of bring able to form metastable foam when air is injected into the solution. The foam was injected into the membrane module at different pressures and concentrations. It was found that the membranes were able to filter the foam solution with rejection increasing with the polymer concentration in the feed. It was also found that, under the same transmembrane pressures (TMPs), the permeate flux was higher with the foam present than without. Depending on the flow conditions, up to 125% increase in flux was observed. It was possible to break the foam solution by concentrating it in a recycled tank and the permeate flux was found to depend on the nature of two-phase flow regime in the membrane tubes. It was possible to predict the permeate flux of the foam solution by modifying the mass transfer coefficient in the theoretical models used for predicting the flux of single-phase flow.
Keywords:FILTRATION;FLUX