Retention of a wide variety of organic pollutants by different nanofiltration/reverse osmosis membranes: controlling parameters of process

Retention of a wide variety of organic pollutants including endocrine disrupting chemicals, plastic additives and low molecular weight priority pollutants from aqueous solutions by the use of many recent type nanofiltration (NF)/reverse osmosis (RO) membranes was investigated. Retention was dependent on membrane type and solute size though other factors such as solute–membrane interaction influenced the result. At low pressure of 0.3 MPa, the high desalting membranes effectively retained virtually all of the semi-volatile organic compounds (SVOCs) at greater than 90% but not the volatile organic compounds (VOCs). The low desalting membrane UTC60, rejected most of the VOCs at lower than 20%. The molecular weight of solutes was useful but the molecular width was a more appropriate parameter for describing the sieving retention by membranes. A multi-linear regression analysis gave the best fitting when the retention was correlated with molecular width, molecular length and logarithm of octonol–water partition coefficient of the target solutes. The prediction indicated that a higher retention will be obtained for a more hydrophobic molecule with a larger width and length.