Pervaporation pollution control

Pollution Control Pervaporation is used to reduce the organic loading of a waste stream, thus effecting product recovery and a reduction in waste-treatment costs. An illustration is a waste stream containing II percent (wt) n-propanol. The residue is stripped to 0.5 percent and 96 percent of the alcohol is recovered in the permeate as a 45 percent solution. This application uses a hydrophobic, rubbery membrane. The residue is sent to a conventional waste-treatment plant. 

A number of applications exist for pervaporation to remove or recover VOCs from water. If the aqueous stream is very dilute, pollution control is the principal economic driving force. However, if the stream contains more than 1-2 % VOC, recovery for eventual reuse can enhance the process economics. 

Process Descriptions Selectively permeable membranes have an increasingly wide range of uses and configurations as the need for more advanced pollution control systems are required. There are four major types of membrane systems (1) pervaporation (2) reverse osmosis (RO) (3) gas absorption and (4) gas adsorption. Only membrane pervaporation is currently commercialized. 

Cole, C.A. and GeneteUi, E.J. 1971. Pervaporation of volatile pollutants from water using selective hollow fibers. J. Water Pollut. Control Fed. 42(8) (Research Supplement to 42, 8, Part 11) R290-R298. 

Hence, their application field is not only restricted to their use in gas separation, pervaporation, and membrane reactors, but are also applicable in microscale devices (microreactors, microseparators, microvalves, microneedles, etc.) and for the preparation of functional materials (adsorbents for pollutant removal, controlled release systems, bactericidal, anticorrosive or antirefiective coatings, chemical sensors, and so on). 

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