Antifouling properties of ionic ultrafiltration polyethersulfone membrane for humic acid removal

Abstract

Humic acid (HA) has been identified as one of the water contaminants, where its presence can affect water quality. Hence, removing HA is required in other to achieve the best quality of water. Ionic liquids (IL) is known with many unique qualities includes negligible vapour pressure, thermal stability, and wide electrochemical stability window. Therefore, by blending IL in membrane formulation, it can help to improve the properties of membranes. This membrane can be applied to remove water contaminants efficiently. In this study, IL, Aliquat 336 was mixed with different amount of polyethersulfone (PES) and dimethylacetamide (DMAC) as new developed ionic ultrafiltration membranes. Pure PES membrane was also fabricated as a control membrane. Non-solvent induced phase separation (NIPS) method was used to fabricate the membrane. After that, membrane was applied in ultrafiltration process to remove humic acid at 20 mg/L. The properties of ionic ultrafiltration membranes such as functional group, hydrophilicity and thermal stability were characterized through fourier transform infrared spectroscopy (FTIR), water contact angle, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) analysis. Then, the ionic ultrafiltration membrane was analyzed through its performance based on adsorption capacity, water flux, HA flux and HA rejection. For the result, the new developed ultrafiltration membrane, M2 successfully achieved pure water flux of 806.08 L/m2.h, is 476.05 L/m2.h for HA flux and 705.61 L/m2.h. for PWF2. M5 has the highest adsorption capacity, 0.32 mg/g. Other than achieving 65° contact angle, M5 membrane also managed to reject HA as 90%.