Magnesium oxide-based adsorbents for carbon dioxide capture: Current progress and future opportunities

Abstract

Adsorption technology has been introduced as one approach to reduce CO2 emissions into the Earth's atmosphere. MgO-based adsorbents are promising due to their abundant availability, wide temperature range, and tuneable physicochemical properties. Over the last decade, there has been a growing number of MgO-based adsorbent studies using various improved approaches that have achieved high CO2 capture performance. For instance, modification using metal/non-metal hybrids and the introduction of promoters, such as alkali metal nitrate/carbonate, and amines to the MgO adsorbent have a significant impact toward enhancing the CO2 uptake capacity and performance stability. Therefore, it is important to provide the latest review on MgO-based adsorbents prepared via various modification strategies using promoters, such as alkali metal nitrate/carbonate (molten salt), amines, and metal oxides, and their relationship with the CO2 uptake performance. In this study, the adsorbent preparation method and CO2 adsorption mechanism are discussed, in which the ambient adsorption pressure conditions, which is typically related to the flue gas of the post-combustion working conditions, were emphasised. Several recommendations for future studies have also been proposed.