(686d) Effect of Thermal Treatment on the Characteristics of  PES/PVA Nanocomposite Membranes Modified with TiO2 Nanoparticles :a Comparitive Study Between 1-Step and 2-Step Thermal Treatment

PES/PVA thin film composites were modified with TiO2 nanoparticles via dip coating method. Thermal treatment of total modified membranes plays a semi-"catalytic role" in coating process. Hence, 4-temprature levels were selected and investigated, noticing that there is an important restriction due to the stability limitation of polymers under thermal treatment process. This phenomenon also leads to the concept of 2-step treatment. 2-step thermal treatment is a more moderate process which leads to a more stable structure.

Polyethersulfone (PES) ultrafiltration membrane was prepared via phase inversion induced by immersion precipitation. Poly(vinyl-alcohol) (PVA) (1.5 wt%) dissolved in distillated water was coated on the surface of PES barrier layer with dip coating technique. The PVA-coated membranes were then immersed in the cross-linking solution containing 5 wt.% of GA and 0.5 wt.% of H2SO4 for 2min at room temperature in order to reduce the membrane swelling by chemical cross-linking. H2SO4 was used as catalyst of reaction. TiO2 nanoparticles were dispersed in distillated water by sonication for 1hr and stirred vigorously for 30 min. the PVA coated membranes were immersed in 0.2 wt% TiO2 solution for 15 min. the last step is thermal treatment which in this study, four level of temperature (85,95.105.115 â??) were investigated. All modified membranes were thermal treated for 3 min.

The performance of modified membranes was tested with filtration of yeast industrial wastewater(COD=11500 mg/L). Permeate flux and COD of four modified membranes have tested. According to the results, the PES/PVA/TiO2 membrane that was thermal treated in 105 â?? had the best output.