Molten salts-modified MgO-based adsorbents for intermediate-temperature CO2 capture: A review

Carbon dioxide (CO2) capture using magnesium oxide (MgO)-based adsorbents at intermediate temperatures has been regarded as a very prospective technology for their relatively high adsorption capacity, low cost, and wide availability. During the past few years, great effort has been devoted to the fabrication of molten salts-modified MgO-based adsorbents. The extraordinary progress achieved by coating with molten salts greatly promotes the CO2 capture capacity of MgO-based adsorbents. Therefore, we feel it necessary to deliver a timely review on this type of CO2 capturing materials, which will benefit the researchers working in both academic and industrial areas. In this work, we classified the molten salts-modified MgO adsorbents into four categories: (1) homogenous molten salt-modified MgO adsorbents, (2) molten salt-modified double salts-based MgO adsorbents, (3) mixed molten salts-modified MgO adsorbents, and (4) molten salts-modified MgO-based mixed oxides adsorbents. This contribution critically reviews the recent developments in the synthetic method, adsorption capacity, reaction kinetics, promotion mechanism, operational conditions and regenerability of the molten salts-modified MgO CO2 adsorbents. The challenges and prospects in this promising field of molten salts-modified MgO CO2 adsorbents in real applications are also briefly mentioned.