Synthesis of heterogeneous metal organic Framework-Graphene oxide nanocomposite membranes for water treatment
Firouzjaei, M.D., Aktij, S.D.
Publication Name: Chemical Engineering Journal
Publication URL: https://doi.org/10.1016/j.cej.2022.140851
Textile wastewater is one of the most challenging streams for wastewater treatment as it is heavily contaminated with solid pollutants such as dyes. Nanofiltration (NF) membranes are a promising method to protect water resources by removing dyes and other organic contaminants from wastewater. In this study, novel NF membranes composed of a thin layer of graphene oxide (GO) and Zn-based metalÐorganic framework (ZIF-7) nanocomposites deposited on chitosan (CTS)-coated polyethersulfone (PES) substrate were fabricated to remove DIRECT RED 16 (DR16) dyes and humic acid from synthetic wastewater. The membrane structure was characterized using a variety of characterization methods such as SEM, XPS, FTIR, AFM, EDX, and water contact angle measurements. Introducing the GO-ZIF-7 nanocomposite layer improved the surface hydrophilicity of membranes by decreasing the contact angle from 84.9 % to 64.5 % for CTS-coated and 5GO-ZIF-7 modified membranes, respectively. This resulted in a greater dye removal rate for the modified membrane (?94 %) compared to the original CTS-coated membrane (?84 %). However, the pure water flux was reduced by 11.4 % due to the introduction of additional resistance layers. Furthermore, the addition of GO-ZIF-7 enhanced the antifouling and anti-biofouling characteristics of modified membranes against various organic and biological foulants, such as sodium alginate and Escherichia coli (E.coli). Overall, the fabricated membrane showed great dye filtration, antifouling, and anti-biofouling performances, by introducing high hydrophilicity, biocidal activities, and a negative surface charge to the membrane surface.