2D materials for adsorption desalination applications: A state of the art

An essential resource for life on the planet is water. Our biological system is severely impacted by contamination and freshwater scarcity due to the massive population increase and industrialization. Adsorption desalination (AD) is a typical solution to the global problem of freshwater scarcity. The layered structure of two-dimensional (2D) materials gives unique interactions with water vapor that can be used as an adsorbent material in AD systems. This paper presents an overview of 2D materials-based-water vapor adsorption and its application in AD systems. It also illustrates the effect of salt hydrate with the 2D vermiculite adsorbent on water vapor adsorption capacity. The effect of adding the 2D materials to metal–organic frameworks adsorbent for water vapor adsorption has been provided. A comparison of various 2D absorbent materials for desalination applications has been presented. It is found that 2D materials such as vermiculite (VMT) and mesoporous silica nanomaterial (MSN) have a high adsorption capacity of water vapor, while graphene oxide showed a substantial improvement in the adsorption properties of MOF materials. The maximum adsorption capacity reached1.94 kg_H2O/kg_VMT for VMT/LiBr at 23 °C and 0.94 relative pressure, while the MSN achieved 1.12 kg_H2O/kg_MSN at 25 °C and a relative pressure of 0.95. The results indicated the effectiveness of 2D materials and are highly recommended for improving the water productivity of AD systems.