Abstract
Chlorine, a crucial basic chemical, is primarily produced by the electrolysis of chloride-containing brines, a highly energy-intensive process with a substantial carbon footprint. Notably, concentrated chloride-containing brines, e.g., acidic wastewater, desalination wastewater, seawater, possess significant osmotic energy, which can be harnessed using membrane-based diffusion cells. Considering this, we here present a spontaneous chlorine production method by using the inherent energy and chloride ions present in these brines. The method is first demonstrated with simulated acidic wastewater because in industry, diffusion cells are already widely used to recycle waste acid. Sulfonated covalent-organic framework membranes are employed to facilitate the diffusion of protons and reject multi-valent cations, purifying acid and avoiding side reactions on the anodes. Consequently, our method simultaneously recovers acid, produces hydrogen and chlorine without consuming external energy. We also validate the general applicability of the method with simulated desalination wastewater. Since our method is compatible with the diffusion-based industrial processes, it holds significant promise for facile, scalable implementation. We also expect the method to be extended for the spontaneous production of other crucial chemicals such as ammonia from nitrate-containing brines.
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Source data are provided with this paper. All the raw data relevant to the study are available from the corresponding author upon request. Source data are provided with this paper.
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Acknowledgments
This work was supported by the National Natural Science Foundation of China (22272194), QIBEBT/SEI/QNESL (S202303), the Shandong Provincial Natural Science Foundation (ZR2021YQ12), the Key R&D Project of Shandong Province (2022CXGC010302), Shandong Postdoctoral Science Foundation (No. SDCX-ZG-202303046) and the Post-Doctoral Applied Research Project of Qingdao (No. QDBSH20220202048). The authors acknowledge the use of ChatGPT to correct language errors.
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C.Z. and J.G. conceived the idea and designed the experiments. C.Z., Q.L., and S.P. carried out the material synthesis, characterization and performance tests. C.Z., M.L., and B.Z. performed the data analysis. C.Z. wrote the manuscript. The project was mainly supervised by J.G., with help from L.J. J.G. revised the manuscript with input from all authors.
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Zhu, C., Li, Q., Li, M. et al. Spontaneous chlorine production from chloride-containing brines. Nat Commun (2026). https://doi.org/10.1038/s41467-025-68181-7
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DOI: https://doi.org/10.1038/s41467-025-68181-7
