**3.5 Comparison between PA and CA membrane**

For PA membrane, the chlorine is and other strong oxidants the biggest threat and can destroying the membrane structure and consequently reduce the salt rejection performance of the membrane. In order to biofouling control in nanofiltration and RO membranes, Oxidants are widely used, so, before separation, the feed water to PA membrane has to be dechlorinated. In **Table 4**, the key parameters of polyamide and cellulose acetate RO membrane has been shown.
