Researchers develop ceramic membrane technology with ultra-precise control of nanopores and surface structure
Dr. Hong-Ju Lee and Dr. In-Hyuk Song of the Nano Materials Research Division at the Korea Institute of Materials Science (KIMS) have successfully developed both a manufacturing process that enables nanoscale smoothing control of ceramic membrane surfaces and membrane materials capable of precisely filtering contaminants even under low-pressure conditions.
This technology addresses key limitations of conventional water-treatment membranes, which typically require high energy consumption and complex processing. The research is published in the Journal of Membrane Science.
Ceramic membranes are essential materials for water treatment in extreme environments due to their excellent chemical and thermal stability, with applications including industrial wastewater treatment, seawater desalination, and the production of ultrapure water for semiconductor processes.
Their performance is determined by how precisely the pore size—which functions as the filtration network—can be controlled, as well as how smoothly the surface of the supporting substrate is formed.
However, conventional manufacturing methods require complex processes involving repeated coating of multiple membrane layers onto the substrate followed by high-temperature sintering, resulting in significant energy consumption. In addition, surface roughness generated during these processes frequently causes microcracks in the upper separation layer, leading to performance degradation.
Furthermore, nanofiltration membranes typically operate only under high pressure (around 10 bar), which increases operating costs and limits their industrial applicability.
To address these challenges, the research team developed a Mutual Doping technique that enhances interparticle bonding by mixing particles from different layers, along with a Co-sintering process that fires all layers simultaneously.
Through this approach, the sintering temperature—previously around 1,300°C—was reduced to approximately 1,000°C, while improving particle sinterability to achieve a dense and robust ceramic structure even at lower temperatures.
In particular, the team achieved an ultra-flat surface that would be difficult to realize using conventional multi-step processes, reducing surface roughness by more than half (from 24.49 nm to 11.74 nm). This resulted in a manufacturing process that fundamentally suppresses crack formation in the separation membrane.
In addition, the research team secured a zirconia (ZrO₂)-based loose nanofiltration membrane material technology capable of delivering high separation performance even under low-pressure conditions. By coating a self-developed eco-friendly aqueous zirconia (ZrO₂) sol onto the smooth substrate formed through the mutual doping process, they produced a membrane in which both size-exclusion effects from fine pores and electrostatic repulsion operate simultaneously.
This membrane removes more than 99.8% of dyes from dye-containing wastewater while selectively allowing salt ions to pass through, even at low pressures comparable to tap-water conditions (2 bar).
The technology resolves the long-standing challenge of separating ions and dyes—a limitation of conventional commercial membranes—thereby expanding the paradigm of water treatment from simple contaminant removal to resource recovery.
Furthermore, the high water permeability significantly improves processing efficiency, while the excellent chemical stability of ceramics and strong flux recovery characteristics enhance both membrane lifetime and economic viability.
This study is significant in that it integrates materials technology and manufacturing process innovation to deliver a next-generation water-treatment solution capable of simultaneously controlling micropores and process defects.
By addressing two major challenges—process simplification and low-pressure operation—the research demonstrates an environmentally friendly, resource-circulating water-treatment technology that balances both economic feasibility and performance.
In particular, the near-defect-free surface control and high energy efficiency represent a novel approach that surpasses the limitations of conventional membrane technologies for water treatment.
The technology can be widely applied to fields requiring highly precise water purification, such as treatment of dyeing wastewater in the textile industry and the production of ultrapure water for semiconductor processes. In particular, its high-efficiency operation makes it possible to significantly reduce energy costs and carbon emissions in large scale water treatment plants.
By securing core technologies in the high-value ceramic membrane market, a field traditionally led by advanced countries, the innovation is expected to lessen dependence on imports and expand its application as a strategic technology for responding to global environmental regulations.
Dr. Hong-Ju Lee, Senior Researcher and principal investigator at KIMS, said, "The significance of this work lies in securing both low-pressure-operable material technology and a manufacturing process capable of implementing it without defects." He added, "We will continue our efforts not only to localize high-value ceramic membranes that have been entirely import-dependent, but also to advance this technology toward leading the global market in the future."
The research team is currently focusing on scale-up studies for large-area ceramic membrane fabrication and mass production based on the secured technology, and has completed domestic and international patent filings for the core technologies involved.
Moving forward, they plan to verify industrial applicability through pilot-scale demonstrations and pursue technology transfer to relevant companies.
More information:
Danyal Naseer et al, Controlling substrate surface roughness via co-sintering of MF/UF-range sublayers ceramic membranes for high-integrity mesoporous top-layer coatings, Journal of Membrane Science (2026). DOI: 10.1016/j.memsci.2025.124915
Provided by National Research Council of Science and Technology
