Laminar Graphene Oxide Membranes Towards Selective Ionic and Molecular Separations: Challenges and Progress Akbar Ali, [a, c] Muhammad Aamir, [b] Khalid Hussain Thebo,* [c] and Javeed Akhtar* [b] Abstract: Resolution of resources and environmental crises requires an efficient separation technologies, consequently, scientists and engineers are working vigorously for ideal separation materials. Laminar graphene oxide (GO) is a two-dimensional (2D) material offers considerable interest in this field due to its single atomic layer thickness, good stability, chemical inertness, and variety of functional groups. Recently, GO have emerged as a novel membrane material for molecular and ionic separation of gases, solvent, water, and desalination applications. This tutorial review aims to discuss the various approaches used to control the stacking of GO-based membrane with emphasis of advantages and drawbacks associated with each approach. Further, attention will also be given to describe the recent progress in GO based membranes for ionic and molecular separations. Meanwhile, challenges and opportunities will also be discussed in detail. We hope this review expected to provide a compact source of information that will be of great interest to chemists, material scientists, physicists, and engineers working or planning to work in GO based membranes for separation applications. Keywords: Graphene oxide, two-dimensional, separation, purification, filtration, desalination 1. Introduction Recently, membrane technology (MT) for separation and purification has gained enormous attention to overcome environmental and resources based issues. In contrast to conventional separation methods, [1] membrane-based separa- tion has provided selectivity, energy efficient and environ- mental friendliness. [2] High permeability, high selectivity, enhanced thermal and chemical stability are main properties required for ideal membranes. [3] However, the permeability, efficiency, selectivity and cost effectiveness are the major issues that urge the scientists and engineers to explore and construct atomic scale capillaries in membranes for selective and sensitive separation of ionic and molecular species. Thus, a rapid upsurge in research related to membrane technology to achieve aforementioned properties for efficient separation have been observed. Currently, polymeric and inorganic membranes have shown emerging potential in the separation applications. However, permeability, selectivity and high cost are the major obstacles that have been associated with these membranes. Among these, polymers based membranes exhibited lower resistance against chemicals, thermal instability, and low selectivity. [1a] Apart from polymers, zeolites, metal-organic frameworks, and carbon nanotubes are the widely explored materials for membrane based separation applications. Zeolites membranes have shown high thermal stability, hydrophilic and organophilic properties, which make them excellent filters in molecular levels, but unfortunately, limited chemical tailor- ability, high production cost, solid acidity, ion exchange capability, adsorption/release capability and catalytic nature limit their applications. [4] [a] A. Ali CAS State Key Laboratory of Multi-phase Complex Systems, Institute of Process Engineering Chinese Academy of Sciences, Beijing 100190, China [b] Dr. M. Aamir, Dr. J. Akhtar Materials Laboratory, Department of Chemistry, Mirpur University of Science and Technology (MUST), Mirpur-10250 (AJK), Pakistan E-mail: javeed.chem@must.edu.pk [c] A. Ali, Dr. K. H. Thebo University of Chinese Academy of Sciences, 19 A Yuquan Road, Beijing, 100049, China E-mail: thebokhalid@gmail.com Personal Account THE CHEMICAL RECORD DOI: 10.1002/tcr.201900024 Chem. Rec. 2019, 19,1–12 © 2019 The Chemical Society of Japan & Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim Wiley Online Library 1