Many industrial activities depend on separating different substances from one another. These separation processes are essential for tasks such as drug purification, textile dye treatment, and food production. Yet they are also among the most energy-intensive operations in manufacturing, accounting for roughly 40% to 50% of global industrial energy consumption.

Most facilities still rely on traditional approaches such as distillation and evaporation. While effective, these methods require large amounts of energy and contribute significantly to carbon emissions. Membrane-based filtration is generally considered a cleaner alternative, but conventional polymer membranes often contain pores of uneven size. Over time, those pores can change shape or degrade, reducing performance and limiting their usefulness in demanding industrial environments.

Nature-Inspired POMbranes With One-Nanometer Pores

"To address these limitations, we engineered a new class of ultra-selective, crystalline membranes called "POMbranes," which contain pores that are about one nanometer wide, thousands of times thinner than a human hair," said Dr. Shilpi Kushwaha, Senior Scientist at CSMCRI.

The new membranes draw inspiration from biological systems such as aquaporins, which regulate the movement of molecules through precisely sized channels. To achieve this level of control, the researchers used polyoxometalate (POM) clusters. Each cluster contains a naturally occurring opening that is exactly 1 nanometer wide and remains permanently stable.

According to Ms Priyanka Dobariya, a CSMCRI research scholar and co-first author of the article, "These POMs are tiny, crown-shaped metal clusters that have a permanent, perfect hole in their centre that does not change or lose shape, which is the biggest hurdle with traditional plastic filters."

Building an Ultrathin Molecular Sieve

Creating a practical membrane required arranging billions of these tiny ring-like structures into a continuous, defect-free layer. To accomplish this, the researchers attached flexible chemical chains to the POM clusters.

When the modified clusters were placed on water, they naturally spread out and organized themselves into a large-area ultrathin film. By changing the length of the attached chains, the team was able to control how closely the clusters packed together.

"This forced molecules to cross the membrane through the only open path, the one-nanometer holes built into each cluster, allowing the membrane to act like a high-tech sieve," added Dr. Raghavan Ranganathan, Associate Professor at IITGN's Department of Materials Engineering.

Dr. Ranganathan and Mr. Vinay Thakur, a PhD scholar at IITGN and the co-first author of the article, also carried out molecular-level simulations that revealed how the membranes perform their filtering function.

Nearly Ten Times Better Separation Performance

Testing showed that the membranes could distinguish between molecules that differ by only 100-200 Daltons, a level of precision that is extremely difficult to achieve with conventional polymer membranes.

According to Dr. Ketan Patel, Principal Scientist at CSMCRI, this capability could create new opportunities for more sustainable manufacturing processes.

"Our membranes show almost ten times better separation performance compared to existing technologies, while remaining flexible, stable, and scalable," he said.

"Additionally, these membranes are flexible, stable across different acidity levels (pH ranges), and can be manufactured in large sheets. This combination is essential if the membranes are to be adopted widely in industry."

Potential Benefits for Textiles and Water Recycling

The technology could be particularly valuable for India's textile and pharmaceutical industries, both of which play major roles in the country's economy.

India's textile and apparel sector contributes more than 2.3% of GDP and represents approximately 13% of industrial production. The domestic market is currently valued at $160-225 billion and is expected to expand to $250-350 billion by 2030.

Textile dyeing and finishing operations generate large amounts of contaminated wastewater, making dye removal and water reuse ongoing challenges. The new membranes could selectively remove dye molecules while allowing water to be recycled, reducing both freshwater demand and chemical waste. This advantage is especially important as India's wastewater treatment market continues to grow.

Applications in Pharmaceutical Manufacturing

The membranes could also benefit pharmaceutical production, where highly accurate separations are critical for product quality and manufacturing efficiency.

"Processes like drug purification and solvent recovery are both energy-intensive and quality-sensitive," noted Mr. Vinay Thakur. "Highly selective membranes such as these can lower energy use while maintaining the stringent standards required in pharmaceutical production."

A Platform Technology for Sustainable Manufacturing

Researchers describe the new POMbranes as a versatile platform technology. Their adjustable structure, high selectivity, and ability to withstand harsh chemical environments make them suitable for a broad range of industrial separation tasks, from wastewater treatment to advanced chemical manufacturing.

As industries increasingly look for technologies that combine efficiency, durability, and sustainability, molecularly engineered membranes may become an important part of next-generation manufacturing systems. By applying a principle commonly found in biology, precise control at the molecular scale, and adapting it into a scalable materials technology, the researchers have demonstrated how nature-inspired design can help solve major industrial challenges.