Natural gas is one of the most highly used resources, not only as a fuel but also as a raw material for many industrial processes. In addition, it is an environmental friendly fuel due to its lower greenhouse gas emission than that of coal or oil. However, it is a nonrenewable energy source and the quality of the available resources is expected to deplete continuously. In this scenario, membrane technologies can play an important role in the purification of the reduced and contaminated resources, competing with the current technologies owing to their simpler adaptability to different feed compositions, lower energy consumption and investment costs. In this review, the current state of the natural gas sources, including nonconventional resources (tight/shale gas and biogas), is explored, along with the current market status of the conventional natural gas. A comparison between the conventional purification technologies and membrane processes is provided, together with the currently available commercial membranes as well as new materials. Furthermore, the latest materials in research stage are reviewed, pointing out their limitations to the current membranes technologies. Finally, future research trends to overcome the current membrane technology limitations are proposed, and the conclusions are addressed.

天然气是最常用的资源之一，不仅作为燃料，而且还是许多工业过程的原料。此外，由于它的温室气体排放量比煤炭或石油低，因此它是一种环保燃料。但是，它是不可再生的能源，并且可用资源的质量预计将持续消耗。在这种情况下，膜技术可以在纯化减少和污染的资源中发挥重要作用，由于它们对不同饲料成分的适应性更简单，能耗和投资成本更低，因此可以与当前技术竞争。在这篇评论中，探讨了包括非常规资源（致密/页岩气和沼气）在内的天然气资源的当前状态，以及常规天然气的当前市场状况。提供了常规纯化技术和膜工艺之间的比较，以及当前可买到的商业膜和新材料。此外，对处于研究阶段的最新材料进行了综述，指出了它们对当前膜技术的局限性。最后，提出了克服当前膜技术局限性的未来研究趋势，并对结论进行了阐述。