Microfiltration and adsorptive membranes for simultaneous removal of methyl orange and methylene blue using hybrid composites

In this study, polyethylene oxide/bentonite/polyaniline (PEO/Bentonite/PANI) composite membrane with enhanced dye rejection and adsorption was constructed by phase inversion technique for the first time. The prepared membranes (PEO, PEO/Bentonite, and PEO/Bentonite/PANI) are characterized using XRD, FTIR, FESEM, and contact angle. These samples were tested as both filtration and adsorptive membranes. Comparative study for simultaneous removal for methyl orange (MO) and methylene blue (MB) in a mixed dye solution using PEO, PEO/Bentonite, and PEO/Bentonite/PANI membranes was investigated. The FESEM analysis showed that the surface of the composite membrane became uniform, free of agglomerates, and its pores became smaller after hybridization with bentonite and PANI proving the well compatibility between membrane constituents. Additionally, FTIR results demonstrated the good interaction between PEO, bentonite, and PANI in the composite membrane. The dye adsorption performance of the PEO/Bentonite/PANI membrane toward decolorization of MO and MB was studied under various conditions; the adsorbent dose ranged from 1.5 to 3 g/L, dye concentration (2.5, 5, 7.5, 10 mg/L), and pH (3, 5, 7, 9, 11). The results revealed that the composite can remove 94% of MO and 96% of MB. Finally, the rejection of MO and MB through the prepared composite membrane was 83% and 85%, respectively. These results suggest that PEO/Bentonite/PANI membrane can be applied as a pressure filtration and/or adsorption membrane for the removal of other pollutants from wastewater.