Carbon-based materials (e.g., activated carbons, carbon nanotubes, membranes) made of graphene or graphene-oxide structures are attractive and versatile materials. They are vital for a wide range of industries, due to their unique structural and chemical properties such as low density, high porosity, large surface area and stable mechanical properties, among others. The ability to experimentally control adsorbent structural features at the molecular level and recent progress made on modeling realistic carbon-structures and fluids force fields, enable building predictive models from molecular simulations for novel applications. This contribution is devoted to some recent advances and limitations faced in molecular simulation on carbonaceous materials, from building the model of the materials to their application in capturing and separating fluids by adsorption. An overview of recent examples on carbon dioxide capture and separation, and removal of compounds in water mixtures are presented as showcases to highlight the role of molecular simulations in these sustainable processes. Remaining challenges, perspectives and future directions are also provided. (C) 2019 Elsevier B.V. All rights reserved.