Supported liquid membrane pervaporation (SLMPV) is a pervaporation process for separating volatile organic compounds (VOCs) from their dilute aqueous solutions through a supported liquid membrane. It integrates simultaneous extraction of the VOCs from the aqueous solution with vacuum stripping of the VOCs from the organic phase in one membrane module. Using a liquid membrane consisting of nonvolatile hydrocarbons immobilized in the micropores of hydrophobic porous polypropylene hollow fibers with or without a plasma-polymerized ultrathin silicone membrane on the outside diameter of the fibers, trichloroethylene (TCE) was separated and concentrated from its aqueous solution at 25°C and essentially atmospheric pressure. The feed TCE concentration was varied between 50 and 950 ppm; the permeate pressure range was 0.6-70 mmHg. A 78-fiber, 30-33-cm-long module can achieve as much as 98% removal of TCE. The hexadecane SLM is permselective for TCE: the experimental selectivity was 30 000, and the intrinsic selectivity could be as high as 2 × 105, much higher than the values reportedly obtained by any solid membrane. The hexadecane SLM performance indicated long-term stability: about 30% decreases in both pervaporation flux and selectivity were observed in a run lasting 4 months. A mathematical model has been proposed to predict the exit concentration, permeation flux, and selectivity from the properties of the membrane and VOCs and the operating conditions.
All Science Journal Classification (ASJC) codes
- Chemical Engineering(all)
- Industrial and Manufacturing Engineering