New Sustainable Atmospheric Water Harvester for Multi-Daily Freshwater Supply

With increasing water scarcity, atmospheric water harvesting (AWH) provides a sustainable solution by extracting liquid water directly from water vapor. Among emerging AWH sorbents, metal–organic framework (MOF) is particularly attractive due to its high porosity and strong water uptake. However, MOF-based devices are typically either passive limited to once-daily cycles or active systems that require external electricity. This study presents a sustainable atmospheric water harvesting device that collects water multiple times per day without external electricity using hand-operated vacuum pump and a low-temperature sink. To improve portability, MOF powders were immobilized as beads within a porous sponge, achieving water uptake comparable to powders but with faster uptake rates. Vacuum assistance reduced the cycle time by up to 75.5% and increased the water yield per cycle by up to 31.4% under controlled test conditions. In prototype operation, 10 g of MIL-101(Cr) produced about 7 g of water within 1 hour using a hand-operated vacuum pump, compared to about 5 g over 3.5 hours without vacuum assistance. These results validate a multi-cycle, electricity-free harvesting strategy for water scarce environments.