Influence of temperature and cleaning on aromatic and semi-aromatic polyamide thin-film composite NF and RO membranes

Although cleaning removes fouling, it may change the properties of membranes and consequently influence their performance. We have evaluated the combined effect of acidic/alkaline cleaning and temperature on the performance of two aromatic membranes, one a reverse osmosis membrane (HR98PP) and the other a nanofiltration membrane (NF90), two semi-aromatic polypiperazine membranes (NF200, NFT 50) and a Desal 5DK nanofiltration membrane. At the retention minimum of each membrane, the KCl retention and the water permeability were in the order: NFT 50<NF200<Desal 5DK<NF90<HR98PP and HR98PP<NF90< NF200<Desal 5DK