Ultrafast ionic and molecular sieving through graphene oxide based composite membranes

• Published in: Desalination 2021-03, Vol.500, p.114848, Article 114848
• Main Authors: Chandio, Imamdin, Janjhi, Farooque Ahmed, Memon, Ayaz Ali, Memon, Shahabuddin, Ali, Zubair, Thebo, Khalid Hussain, Pirzado, Azhar Ali Ayaz, Hakro, Ayaz Ali, Khan, Waheed S.
• Format: Article
• Language: English
• Subjects: Graphene oxide; Membrane; Permeance; Separation; Serine
• ISSN: 0011-9164
• DOI: 10.1016/j.desal.2020.114848

Graphene oxide (GO) based membranes have been widely explored for water purification and desalination applications, however, it shows less rejection for small ions and molecules, due to lack of pristine graphitic sp2 domains and smaller interlayer spacing. In this work, we fabricate a unique class of GO based composite (cGO) membranes with large interlayer spacing from GO by serine amino acid (SAA) as a cross-linker and reducing agent using simple strategy. The cGO/SAA membrane (~280 ± 20 nm) showed an outstanding separation efficiency for several organic dyes with ultrafast permeability i.e. rhodamine B (Rejection 99 ± 1% and permeance 930 ± 10 Lm−2h−1bar−1), methyl blue (98 ± 1% and permeance 980 ± 10 Lm−2h−1bar−1) and DI water (1050 ± 10 Lm−2h−1bar−1). In addition, these membranes were also used for the separation of different salts such as NaCl, MgCl2, Ni(NO3)2 and Pb(NO3)2 and show good rejection for Pb(NO3)2 up to 92 ± 2%. Beside this, these membranes found to be very stable in aqueous environment for ~65 days. We believe with the help of this strategy, various 2D materials based membranes can be developed and used in water filtration and desalination. Fabricate a unique class of GO based composite (cGO) membranes with large interlayer spacing from GO by serine amino acid (SAA) was carried out using green route followed by vacuum filtration method. The cGO/SAA membranes showed excellence selectivity of dye molecules i.e. rhodamine B ˃99% and good selectivity for salts Pb(NO3)2 up to 92% in aqueous solution with extraordinary stability. [Display omitted] •Fabrication of GO based composite (cGO) membranes with large interlayer spacing from GO by serine amino acid (SAA) using green route.•The cGO/SAA membranes (~280±20 nm) exhibited ultrafast permeability for DI water.•Such membranes showed an outstanding separation efficiency for organic dyes and salts with ultrafast permeability i.e. rhodamine B and Pb(NO3)2.•These membranes were used for separation of different salts and show good rejection for Pb(NO3)2 up to 92±2%.•These membranes are very stable in aqueous environment for ~65 days.