Prototype Development of a Two-Stage Hydrogel–CaCl₂ Absorption–Desorption Device for Atmospheric Water Harvesting

Document Type : Research Paper

Authors

1 M.Sc Graduated, Department of Chemical and Polymer Engineering, Faculty of Engineering, Yazd University, Yazd, Iran.

2 Professor, Department of Chemical and polymer Engineering, Faculty of Engineering, Yazd University, Yazd, Iran

10.22077/jwhr.2025.10340.1189

Abstract

Freshwater scarcity has become a pressing global challenge, driving the need for innovative and sustainable water production technologies. Atmospheric water harvesting offers a promising solution by exploiting the vast reservoir of water vapor in the air, particularly for arid and remote regions. In this study, we developed a novel two-stage moisture absorption–desorption system using a highly hygroscopic hydrogel–CaCl₂ composite (7.4% hydrogel, 92.6% CaCl₂). The device comprises an absorption compartment equipped with 10 trays (0.675 kg of the composite per tray) for capturing atmospheric moisture and a condensation–recovery compartment integrated with a refrigeration system for efficient desorbed vapor condensation. The system operates in cyclic absorption and thermally driven desorption phases, with each phase offering fully programmable and controllable duration. The desorbed vapor is subsequently directed into a condensation chamber, where it is recovered through an integrated refrigeration unit, and discharged from the system. Experimental results demonstrated a freshwater production capacity of approximately 1 L per day, under air relative humidity of approximately 33%. This integrated approach highlights the potential of hydrogel–salt composites coupled with active condensation for atmospheric water harvesting applications.

Keywords

Main Subjects

References

Aleid, S., Wu, M., Li, R., Wang, W., Zhang, C., Zhang, L. & Wang, P. (2022). Salting-in effect of zwitterionic polymer hydrogel facilitates atmospheric water harvesting. ACS Materials Letters, 4(3), 511–520. doi:10.1021/acsmaterialslett.1c00723.
An, F., Akther, N., Duan, X., Peng, S., Onggowarsito, C., Mao, S., Fu, Q. & Kolev, S.D.(2022).  Recent development of atmospheric water harvesting materials: A review. ACS Materials, 2(5), 576–595. doi:10.1021/acsmaterialsau.2c00016.
Du, X., Xie, Z., Zhang, H., Jiang, S., Su, X. & Fan, J. (2025). Robust mix-charged polyzwitterionic hydrogels for ultra-efficient atmospheric water harvesting and evaporative cooling. Advanced Material, 37(33), e2505279 doi:10.1002/adma.202505279.
Kallenberger, P.A. and Fröba, M. (2018). Water harvesting from air with a hygroscopic salt in a hydrogel-derived matrix. Communications Chemistry., 1:28. doi:10.1038/s42004-018-0028-9.
LaPotin, A., Zhong, Y., Zhang, L., Zhao, L., Leroy, A., Kim, H., Rao, S.R. &Wang, E. (2021).  Dual-stage atmospheric water harvesting device for scalable solar-driven water production. Joule, 5(1), 166–182. doi:10.1016/j.joule.2020.09.008.
Lee, Y., Nah, S.H., Wang, K.-Y., Chi, Y., Kim, J.B., Zhang, Z. & Yang, S. (2025). Highly scalable, raspberry-like microbeads with nano-/micro-confined hybrid hydrogel desiccants for rapid atmospheric water harvesting. Advanced Functional Materials, 35(18), 2506725. doi:10.1002/adfm.202506725.
Lei, C., Guo, Y., Guan, W., Lu, H., Shi, W. &Yu, G. (2022). Polyzwitterionic hydrogels for efficient atmospheric water harvesting. Angewandte Chemie International Edition., 61(13). e202200271 doi:10.1002/ange.202200271.
Li, Q., Shao, Z., Zou, Q., Pan, Q., Zhao, Y., Feng, Y., Wang, W., Wang, R. & Ge, T. (2024).  An atmospheric water harvesting system based on the ‘Optimal Harvesting Window’ design for worldwide water production. Science Bulletin. 69(5), 1437–1447. doi:10.1016/j.scib.2024.03.018.
Li, R., Shi, Y., Shi, L. (2018). Hybrid hydrogel with high water vapor harvesting capacity for atmospheric water generation. Environmental Science &Technology, 52(19), 11367–11377. doi:10.1021/acs.est.8b02832.
Min, X., Wu, Z., Wei, T., Hu, X., Shi, P., Xu, N., Wang, H., Li, J., Zhu, B. & Zhu, J. (2023). High-yield atmospheric water harvesting device with integrated heating/cooling enabled by thermally tailored hydrogel sorbent. ACS Energy Letters, 8, 3147–3153.  doi:10.1021/acsenergylett.3c00682.
Ni, F., Xiao, P., Zhang, C. and Chen, T. (2022).  Hygroscopic polymer gels toward atmospheric moisture exploitations for energy management and freshwater generation. Matter, 5,2624–2658. doi:10.1016/j.matt.2022.06.033.
Park, H., Haechler, I., Schnoering, G., Ponte, M.D., Schutzius, T.M. and Poulikakos, D. (2022).  Enhanced atmospheric water harvesting with sunlight-activated sorption ratcheting. ACS Appllied Materials &Interfaces, 14(2).2237–2245. doi:10.1021/acsami.1c18852.
Yang, X., Chen, Z., Xiang, C., Shan, H. & Wang, R. (2024). Enhanced continuous atmospheric water harvesting with scalable hygroscopic gel driven by natural sunlight and wind.  Nature Communicatins, 15, 7678. doi:10.1038/s41467-024-52137-4.
Water Harvesting Research
Volume 8, Issue 2
Issue in Progress
2025
Pages 258-266

Files

Share

How to cite

Statistics