Thermostable PPESK/TiO2 nanocomposite ultrafiltration membrane for high temperature condensed water treatment

Poly (phthalazine ether sulfone ketone) (PPESK)/TiO2 organic–inorganic composite ultrafiltration (UF) membranes with enhanced performance for high temperature condensed water treatment were prepared using a phase-inversion method. The effects of TiO2 concentration on the membrane morphologies, physic-chemical properties, membrane permeability and antifouling performance were investigated and discussed. The SEM result reveals that the penetrated finger-like structure in sublayer is suppressed, and sponge-like structure begins to be developed. The mechanical strength and thermal stability of composite membrane are improved due to the existence of hydrogen bond between TiO2 and polymer. The permeate flux is also enlarged due to the improved hydrophilicity and porosity. Compared with neat PPESK membrane, the composite membranes present improved antifouling properties, showing lower filtration resistances, MFI values and better flux recover property during high temperature condensed water treatment. The optimal addition amount of TiO2 is 2 wt.%. The high temperature condensed water with excess oil and iron can be treated efficiently using PPESK/TiO2 composite membrane. The turbidity of feed solution is almost removed. The oil and iron concentrations in permeate solution are 0.89 mg/L and 26.4 μg/L which meet the Quality Criterion of Water and Steam for Steam Power Equipment in China.

► PPESK/TiO2 nanocomposite UF membranes were prepared by phase-inversion method.
► The mechanical strength, thermal stability and hydrophilicity were improved.
► The composite membranes showed better permeability and antifouling properties.
► The excess oil and iron in high temperature condensed water were removed efficiently.
► Reclaiming high temperature condensed water can save energy and realize water cycle.