Abstract
Inorganic scaling, governed by complex organic–inorganic interactions, presents a pervasive challenge in aqueous environments with broad implications for engineering systems. Using reverse-osmosis (RO) desalination as a model platform, we investigate how mixed organic foulants influence inorganic gypsum scaling at membrane–water interfaces. Representative proteins, humic substances, and polysaccharides are employed as model foulants to reveal their roles in modulating gypsum crystallization behavior. By integrating advanced in situ, time-resolved synchrotron X-ray scattering within the concentration polarization layer—a region typically inaccessible to conventional characterization techniques—with modelling, spectroscopic, and imaging analyses, we track the evolution of gypsum scaling from nanoscale precursors to mature crystals. Our findings reveal that different classes of organic foulants regulate gypsum crystallization through distinct mechanisms, ranging from inhibiting precursor aggregation in the bulk solution to altering interfacial physicochemical properties that govern the kinetics of heterogeneous nucleation and growth. These findings provide molecular-level insights into the coupled dynamics of organic fouling and inorganic scaling, advancing mechanistic understanding of crystallization at functional interfaces. Such insights offer guidance for the rational design of anti-scaling strategies in engineering systems.
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Acknowledgements
We gratefully acknowledge the financial support from the National Science Foundation of China (52170094 and 22576197 to X.L.) and the Fundamental Research Funds for the Central Universities (to X.L.). We thank the National Facility for Protein Science in Shanghai of BL19U2 for providing technical support and assistance in SAXS/WAXS measurements. We also thank the Shanghai Synchrotron Radiation Facility of BL10U1 and BL16B1 for the assistance on USAXS/SAXS/WAXS measurements. We thank the National Synchrotron Radiation Laboratory of BL01B for the assistance on infrared mapping measurements. Some material characterization was carried out at the University of Science and Technology of China (USTC) Center for Micro- and Nanoscale Research and Fabrication, the Instruments Center for Physical Science at USTC, and the First Affiliated Hospital of USTC. We are grateful to Mr. Qingbo Xu at USTC for his assistance with the detector calibration for SAXS and WAXS measurements.
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X.L. conceived the idea. Z.F. and X.L. designed experiments. Z.F., S.X., and Z.R. performed experiments. J.C. conducted crystallographic analysis. Z.F., S.X., J.C., Y.Y., J.J., X.F., and X.L. contributed to the data interpretation. Z.F., Z.R., and X.L. wrote the first draft. X.L., Z.F., S.X., and Y.Y. revised the manuscript. All the authors discussed the results.
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Nature Communications thanks Wenhai Luo, Yuelian Peng, Zhengyang Huo and the other, anonymous, reviewer(s) for their contribution to the peer review of this work. A peer review file is available.
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Feng, Z., Xu, S., Cao, J. et al. In situ synchrotron X-ray scattering reveals organic-mediated scaling mechanisms on desalination membranes. Nat Commun (2026). https://doi.org/10.1038/s41467-026-70508-x
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DOI: https://doi.org/10.1038/s41467-026-70508-x
