Water adsorption in MOFs: fundamentals and applications This review discusses the fundamental and practical aspects of water adsorption in Metal-Organic Frameworks (MOFs). It covers the stability of MOFs in water, a crucial issue for many applications. Both stability in gaseous and aqueous media are considered. Different mechanisms of water adsorption in MOFs are presented: reversible and continuous pore filling, irreversible and discontinuous pore filling through capillary condensation, and irreversibility arising from the flexibility and possible structural modifications of the host material. Water adsorption properties of more than 60 MOF samples are reported. The applications of MOFs as materials for heat-pumps and adsorbent-based chillers and proton conductors are also reviewed. Some directions for future work are suggested as concluding remarks. The review begins with an introduction to the importance of water stability in MOFs for industrial applications such as gas storage and separation, sensing, catalysis, and proton conduction. It discusses the degradation of MOFs in the presence of water, which has limited their industrial applications. The review then presents the stability of MOFs in humid atmospheres and in aqueous media, and presents the different degradation-dissolution mechanisms. The control of water adsorption in microporous solids is crucial for the development of industrial processes. For instance, the temperature required for the regeneration of adsorption or chromatography columns made up of molecular sieves is governed by their water adsorption properties. On the other hand, hyperhydrophobic zeolites can be applied for molecular springs upon water intrusion. Water adsorption is often detrimental for CO2 capture using hydrophilic materials since water acts as a strong competitor. However, it was demonstrated that controlled water adsorption can enhance CO2 capture in MOFs such as MOF-100, HKUST-1, MIL-101 and MIL-53. The review then discusses the stability of MOFs in the presence of water, including stability in pure water and aqueous acid/base. It discusses the effects of pore size, pore morphology, and flexibility on water adsorption. The review also discusses the structure-stability relationships, including the metal-ligand bond, and the degradation mechanisms of MOFs in water. The review concludes with a discussion of water adsorption-desorption in MOFs, including the adsorption-desorption mechanisms, water adsorption-desorption isotherms, and the effects of hydration-dehydration on the adsorption properties of MOFs. The review highlights the diversity of water adsorption properties in MOFs and their applications in various fields.Water adsorption in MOFs: fundamentals and applications This review discusses the fundamental and practical aspects of water adsorption in Metal-Organic Frameworks (MOFs). It covers the stability of MOFs in water, a crucial issue for many applications. Both stability in gaseous and aqueous media are considered. Different mechanisms of water adsorption in MOFs are presented: reversible and continuous pore filling, irreversible and discontinuous pore filling through capillary condensation, and irreversibility arising from the flexibility and possible structural modifications of the host material. Water adsorption properties of more than 60 MOF samples are reported. The applications of MOFs as materials for heat-pumps and adsorbent-based chillers and proton conductors are also reviewed. Some directions for future work are suggested as concluding remarks. The review begins with an introduction to the importance of water stability in MOFs for industrial applications such as gas storage and separation, sensing, catalysis, and proton conduction. It discusses the degradation of MOFs in the presence of water, which has limited their industrial applications. The review then presents the stability of MOFs in humid atmospheres and in aqueous media, and presents the different degradation-dissolution mechanisms. The control of water adsorption in microporous solids is crucial for the development of industrial processes. For instance, the temperature required for the regeneration of adsorption or chromatography columns made up of molecular sieves is governed by their water adsorption properties. On the other hand, hyperhydrophobic zeolites can be applied for molecular springs upon water intrusion. Water adsorption is often detrimental for CO2 capture using hydrophilic materials since water acts as a strong competitor. However, it was demonstrated that controlled water adsorption can enhance CO2 capture in MOFs such as MOF-100, HKUST-1, MIL-101 and MIL-53. The review then discusses the stability of MOFs in the presence of water, including stability in pure water and aqueous acid/base. It discusses the effects of pore size, pore morphology, and flexibility on water adsorption. The review also discusses the structure-stability relationships, including the metal-ligand bond, and the degradation mechanisms of MOFs in water. The review concludes with a discussion of water adsorption-desorption in MOFs, including the adsorption-desorption mechanisms, water adsorption-desorption isotherms, and the effects of hydration-dehydration on the adsorption properties of MOFs. The review highlights the diversity of water adsorption properties in MOFs and their applications in various fields.