Energy-efficient atmospheric water harvesting using MOF-801 and microwave-synthesized Al-fumarate: linking micro–mesoporous structure to sorption and regeneration behavior

Atmospheric water harvesting (AWH) has emerged as a promising route to mitigate freshwater scarcity in arid and semi-arid regions. Existing studies typically evaluate individual metal–organic frameworks (MOFs) under limited conditions, leaving a gap in comparative assessments that link pore architecture to sorption behavior. This work aims to establish a direct, climate-relevant comparison between MOF-801 and Al-fumarate, for AWH applications. The sorbents were synthesized and characterized using XRD, FTIR, BET, SEM, and TGA to elucidate their structural and textural properties. Water vapor adsorption–desorption performance was quantified under controlled relative humidity and temperature, supported by thermodynamic analysis of the isosteric heat of adsorption. MOF-801 demonstrated higher water uptake at moderate humidity (0.247 g H 2 O g − 1 at 40% RH and 20°C), while Al-fumarate showed enhanced performance under more humid conditions (0.278 g H 2 O g − 1 at 80% RH and 25°C). Both sorbents were regenerated at ~ 80°C, corresponding to an energy requirement of 1.2–1.5 MJ L − 1 . Thermodynamic analysis indicated a higher initial isosteric heat of adsorption (Q st ) for MOF-801, consistent with stronger water-framework interactions in drier atmospheres, whereas Al-fumarate exhibited a flatter Q st profile favorable for humid conditions. Both materials were further evaluated in four-month field tests in contrasting humid (Rasht) and arid (Isfahan) climates to assess cycling stability. The results providing practical guidelines for selecting energy-efficient MOFs tailored to specific climatic conditions