International Journal of Greenhouse Gas Control xxx (xxxx) xxx Please cite this article as: Guoqiang Li, International Journal of Greenhouse Gas Control, https://doi.org/10.1016/j.ijggc.2020.103195 1750-5836/© 2020 Elsevier Ltd. All rights reserved. A review - The development of hollow fbre membranes for gas separation processes Guoqiang Li a , Wojciech Kujawski a, b, *, Robert V´ alek c , Stanisław Koter a a Nicolaus Copernicus University in Toru´ n, Faculty of Chemistry, 7, Gagarina Street, 87-100, Toru´ n, Poland b National Research Nuclear University MEPhI, 31, Kashira Hwy, Moscow, 115409, Russia c MemBrain, 87, Pod Vinicí, 471 27, Str´ aˇ z pod Ralskem, Czech Republic A R T I C L E INFO Keywords: Gas separation Hollow fbre membranes Thin flm composite membranes Mixed matrix membranes Dry-jet wet spinning parameters ABSTRACT Gas separation is an important separation process to many industries, and membrane separation using hollow fbre membranes (HFMs) has become one of the emerging technologies. In this article, the gas separation con- cepts, gas transport mechanism, and the fabrication and gas separation performance of HFMs including asym- metric HFMs, thin flm composite hollow fbre membranes (TFC-HFMs), and mixed matrix hollow fbre membranes (MM-HFMs), are reviewed and discussed. Dope composition and spinning parameters directly in- fuence the structure of HFMs and subsequently the gas separation performance of HFMs. The gas separation performance of TFC-HFMs can be improved by the design of the coating solution, surface modifcation, and the addition of both a gutter layer and a protective layer. Mixed matrix membranes (MMMs) have been intensively investigated in fat sheet membranes and the inspiring gas separation results have been obtained. Therefore, the incorporation of nanoparticles into hollow fbre membranes is a desirable solution to increase the gas perme- ability and selectivity simultaneously. The functionalization of nanoparticles and fabrication methods of MM- HFMs are also presented. 1. Introduction Gas separation is indispensable in many industrial processes, including biogas upgrading, natural gas sweetening, fue gas treatment, hydrogen purifcation, and nitrogen production (Adewole et al., 2013; Kentish et al., 2008; Li et al., 2015a; Seong et al., 2020). Natural gas which contains mainly methane is the cleanest, safest, and most effcient energy source. To meet the quality standards for its practical applica- tions, raw natural gas needs further purifcation. For example, CO 2 as an acid gas must be removed to enhance energy content and to reduce pipeline corrosion (Adewole et al., 2013; Biondo et al., 2018; George et al., 2016). Because of the depletion of fossil fuels, biogas consisting of 6070 vol% CH 4 and 30–40 vol% CO 2 , becomes an important renew- able energy resource. However, CO 2 , as one of the unavoidable impu- rities of biogas, should be removed to increase the energy grade, prevent pipeline corrosion, and mitigate climate change (Gong et al., 2020). Hydrogen is an environmental friendly and sustainable energy carrier and storage medium. However, raw hydrogen produced from thermo- chemical process or dark fermentation process cannot meet the purity demands in many cases. For example, high purity hydrogen (> 99.99 vol %) is needed for its application in fuel cells. Therefore, it is essential to perform hydrogen purifcation to meet the purity requirements of various potential applications (Li et al., 2015a). In 1980, Monsanto became the frst company to establish a com- mercial application of gas separation by launching the Prism membrane for hydrogen separation. By the mid-1980s, Cynara, Separex, and Grace Membrane Systems had established membrane plants to remove carbon dioxide from methane in natural gas. At about the same time, the frst commercial membrane system was launched by Dow to separate nitro- gen from air (Baker, 2012; Kentish et al., 2008). Membranes for natural gas processing were frst commercialized in the 1980s for CO 2 removal (Scholes et al., 2012). Nowadays, membrane technology has found its application in many gas separation processes, including the removal of carbon dioxide from methane, hydrogen, and nitrogen. Compared with conventional technologies such as pressure swing adsorption, chemical absorption, and cryogenic process, membrane separation processes show many advantages, including lower energy consumption, lower capital and processing costs, smaller unit size, easy upscaling, and lower environmental impact (Dai et al., 2016c; Li et al., 2015a; Xu et al., 2018). The membrane plays a crucial role in the membrane separation * Corresponding author at: Nicolaus Copernicus University in Toru´ n, Faculty of Chemistry, 7, Gagarina Street, 87-100, Toru´ n, Poland. E-mail address: kujawski@chem.umk.pl (W. Kujawski). Contents lists available at ScienceDirect International Journal of Greenhouse Gas Control journal homepage: www.elsevier.com/locate/ijggc https://doi.org/10.1016/j.ijggc.2020.103195 Received 29 June 2020; Received in revised form 24 September 2020; Accepted 21 October 2020