Non-solvent induced phase separation NIPS

TCA removal was also studied using SBS asymmetric membranes prepared by non-solvent induced phase separation (NIPS), as reported in the US patent by Sikdar et al. (2008). In this work, the temperature and vacuum pressure were varied while the feed concentration ( 120 ppm) was kept constant. TCA, water and total flux increased with increasing the temperature (from 10°C to 35°C) at the constant pressure of 0.05 bar. At a permeate pressure of 0.05 bar and temperature of 34°C, TCA flux was about 0.018 kg m i. Separation factor ((Ztca/Hjo) increased from 900 to 4600 at higher temperature (from 10°C to 35°C) and from 640 to 2300 changing the permeate pressure from 0.01 to 0.05 bar. 

Non-solvent induced phase separation (NIPS), or diffusion-induced phase separation, involves dissolution of the polymer in a good solvent in order to obtain a homogeneous solution, followed by the addition of a non-solvent miscible with the first solvent. This will cause precipitation of the polymer when the non-solvent concentration becomes significant. 

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