New desalination membrane allows chlorine disinfection

Researchers at Virginia Tech have created a new polymer membrane for reverse osmosis (RO) that will not be degraded by chlorine, making it possible for water to be disinfected with the chemical.

According to James McGrath, university professor of chemistry at Virginia Tech, USA , the new polymer material grew out of the researchers' work on proton exchange membrane (PEM) materials used in fuel cells. "The polymer structure is similar, but PEM materials are treated with a dilute acid and the RO materials are treated with a salt to put them in the neutral form," he says.

The membrane itself is asymmetric and incorporates a rigid foam with a thin membrane skin. The separation takes place at the skin and the water passes quickly through the foam's large pores. Without the foam, the skin or film layer is not strong enough to withstand the pressure of RO.

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