Separation of endocrine disruptors from aqueous solutions by pervaporation

Separation of endocrine disrupting chemicals from aqueous solutions was investigated by pervaporation using hydrophobic polydimethylsiloxane (PDMS) membranes. 1,2-Dibromo-3-chloropropane (DBCP, MW=236.4 g/mol), which is commonly used as a soil fumigant in the agricultural industry, was selected as a model endocrine disrupting compound. DBCP could be separated very efficiently from very dilute aqueous solutions through PDMS membranes by pervaporation when the vacuum line between pervaporation cell and a cold trap on the permeate side was heated to 150 °C. The separation factor of endocrine disruptors over water depended significantly on membrane thickness. This effect was caused by concentration polarization of the highly permeable endocrine disruptor. As the thickness of the PDMS membranes decreased, concentration polarization caused a significant reduction in separation factor. Pervaporation of other organic compounds from dilute aqueous solutions through PDMS membranes was also performed. The separation factors of the organic compounds could not be correlated well with their molecular size. As expected, hydrophobic organic chemicals showed higher separation factors than those of hydrophilic organic compounds using hydrophobic PDMS membranes.