Enhanced atmospheric water harvesting efficiency through green-synthesized MOF-801: a comparative study with solvothermal synthesis

Abstract

Adsorption-based atmospheric water harvesting has emerged as a compelling solution in response to growing global water demand. In this context, Metal–organic frameworks (MOFs) have garnered considerable interest due to their unique structure and intrinsic porosity. Here, MOF 801 was synthesized using two different methods: solvothermal and green room temperature synthesis. Comprehensive characterization indicated the formation of MOF-801 with high phase purity, small crystallite size, and excellent thermal stability. Nitrogen adsorption–desorption analysis revealed that green-synthesized MOF-801 possessed an 89% higher specific surface area than its solvothermal-synthesized counterpart. Both adsorbents required activation at a minimum temperature of 90 °C for optimal adsorption performance. Additionally, green-synthesized MOF-801 demonstrated superior adsorption performance compared to solvothermal-synthesized MOF-801, attributed to its small crystal size (around 66 nm), more hydrophilic functional groups, greater specific surface area (691.05 m2/g), and the possibility of having a higher quantity of defects. The maximum water adsorption capacity in green-synthesized MOF-801 was observed at 25 °C and 80% relative humidity, with a value of 41.1 g/100 g, a 12% improvement over the solvothermal-synthesized MOF-801. Remarkably, even at a 30% humidity level, green-synthesized MOF-801 displayed a considerable adsorption capacity of 31.5 g/100 g. Importantly, MOF-801 exhibited long-term effectiveness in multiple adsorption cycles without substantial efficiency decline.

Fabry–Pérot Cavity Based on Metal–Organic Framework/Graphene Oxide Heterostructure Membranes for Humidity Sensing

“…For GO sheets, the peak at 3376 cm –1 indicates O–H of the COOH group and at 1719, 1618, and 1046 cm –1 are identified as the vibration of CO (carboxyl/carbonyl), CC, and C–O stretching, respectively. The above characteristic peaks are consistent with the existing FTIR studies. , Figure b gives an SEM image of a single particle of MOF-801. The morphology of MOF-801 particles shows circular, and the average particle size is 150 nm.…”

Bimetallic PCN-333 with Modulated Crystallization and a Porosity Structure for a Highly Efficient Removal of Congo Red

“…Notably, when compared to other series samples, these two samples demonstrate a substantial increase in pore volume within the 2–4 nm pore size range, indicating the presence of hierarchical porosity . This increase in the pore volume is advantageous for enhancing the specific surface area and facilitating the exposure of additional active sites. , …”

Terahertz Spectroscopy Unambiguously Determines the Orientation of Guest Water Molecules in a Structurally Elusive Metal–Organic Framework

“…Porous materials represent one of the most exciting areas of materials science, as they hold potential to revolutionize a number of different areas of chemistry, ranging from gas storage to drug delivery. − One important area that has shown great promise involves passive water harvesting for clean water generation. − Researchers have described a number of different materials in recent years that are designed to uptake atmospheric water at one relative humidity while releasing it at a different (often lower) humidity. ,, For metal–organic frameworks (MOFs) in particular, the uptake parameters are optimized to work in a particular environment such that these materials offer a robust, economical, and energy-efficient approach to producing clean water. , In order to better understand and design such systems, one requires a detailed understanding of the structure and dynamics of the frameworks, with and without water present, as it is well-known that the location and orientation of guest molecules can have a profound impact on bulk physical properties. However, identifying the structure of guest molecules turns out to be a significant challenge. , It requires the growth of large single-crystal samples, and in the case of water specifically, it likely requires neutron diffraction measurements in order to locate the hydrogen atoms, as X-rays are poorly diffracted by protons. − For MOFs in particular, this is especially difficult, as many MOFs only form submicrometer-sized crystallites, which typically can only be characterized with powder diffraction measurements.…”

“… 1 − 5 One important area that has shown great promise involves passive water harvesting for clean water generation. 6 − 8 Researchers have described a number of different materials in recent years that are designed to uptake atmospheric water at one relative humidity while releasing it at a different (often lower) humidity. 6 , 9 , 10 For metal–organic frameworks (MOFs) in particular, the uptake parameters are optimized to work in a particular environment such that these materials offer a robust, economical, and energy-efficient approach to producing clean water.…”

“… 6 − 8 Researchers have described a number of different materials in recent years that are designed to uptake atmospheric water at one relative humidity while releasing it at a different (often lower) humidity. 6 , 9 , 10 For metal–organic frameworks (MOFs) in particular, the uptake parameters are optimized to work in a particular environment such that these materials offer a robust, economical, and energy-efficient approach to producing clean water. 11 , 12 In order to better understand and design such systems, one requires a detailed understanding of the structure and dynamics of the frameworks, with and without water present, as it is well-known that the location and orientation of guest molecules can have a profound impact on bulk physical properties.…”