Effect of Potassiume Dichromate as an Oxidizing Agent on Hydrophilicity of Microporous Polysulfone Membranes

Polysulfone (PSf) is a widely used materail in membrane for ultrafiltration (UF), nanofiltration (NF), microfiltration (MF), gas separation and hemodialysis due to its thermal stability, mechanical strength, and chemical inertness. However due to its hydrophobic nature, these membranes are severely fouled during filtration of protein containing solutions. A simple, inexpensive and environmental friendly chemical treatment process, i.e., treating PSf membrane by a mixture of potassium dichromate (K2Cr2O7) and sulfuric acid, was proposed to improve the hydrophilicity of PSf membrane. To evaluate the effectiveness of this strong oxidation treatment, contact angle measurement was used to measure the hydrophilicity of treated membrane. The effects of concentration of oxidizing agent and time of treatment were also studied.. Membrane were immersed into the mixture of 5.5%(w/w), 3.5%(w/w) and 1.5%(w/w) K2Cr2O7 in 7M aqueous solution of sulfuric acid for various time intervals. Obtained results showed that the contact angle was decreased from 100 to 55 when membrane were immersed for 60 min. The change in chemical properties of PSf membranes were examined by attenuated reflection-Fourier transform infrared (ATR–FTIR) spectroscopy. Obtained results confirm that hydrophilic carbonyland hydroxyl groups were successfully introduced on the surface of PSf membrane after treatment.

کلیدواژه ها:

Polysulfone (PSF) ، micro porous membrane ، chemical treatment ، Hydrophilicity ، Potassium dichromate introduction