RESUMO
The removal efficiency of BPA and TBBPA by nanofiltration membrane Desal 5 DK has been investigated with a lab-scale dead-end filtration module and the role of adsorption of two molecules on membrane was also explored to understand the filtration mechanism. The results showed that the R(obs) of BPA decreased from 89% to 47% as the accumulated adsorption quantity of BPA onto the membrane increased to 30 microg x m(-2). The high BPA concentration in adsorption layer caused the water flux decline especially at high pressure. The high TBBPA rejection of over 95% by Desal 5 DK was obtained due to the molecular weight and molecular structure although the accumulated adsorption quantity of TBBPA reached 50 microg x m(-2). The desorption test showed that the TBBPA could not pass through the membrane for its structure at the 5 x 10(5) Pa, while BPA could diffuse through the membrane and the peak concentration was obtained after 30 mL filtration. The quantity of BPA released from the membrane contributed 30% of the total amount adsorbed by the membrane Desal 5 DK.
