Molecules with empty spaces: How MOFs can transform sustainability

On October 8, 2025, the Royal Swedish Academy of Sciences awarded the Nobel Prize in Chemistry to three scientists — Susumu Kitagawa, Richard Robson and Omar M Yaghi — for work that has taken several decades to gain recognition.

Their research focuses on a group of materials known as metal-organic frameworks, or MOFs. These are solid materials that look ordinary, like any fine powder or crystal kept in a laboratory bottle, but their inside structure is full of carefully arranged empty spaces. It is this “emptiness” that scientists are excited about, and not the solid part.

MOFs are made by linking metals with organic compounds. When these two come together, the result is a porous, net-like structure with tiny rooms and pathways that can trap or separate molecules.

What makes MOFs different from older porous materials like activated carbon is that they can be designed on purpose. Scientists can choose the metal, choose the linking molecule and decide how the internal structure should behave. It is not a material you find somewhere and then wonder what to do with; it is made for a particular task.

The people behind the discovery come from different paths. Richard Robson in Australia started exploring the idea in the 1980s, long before anyone imagined it could have commercial or environmental importance. Omar Yaghi, working in the United States in the 1990s, found a way to build these materials in a planned and repeatable manner, not by accident, but like an assembly process. His MOF-5 experiment became the turning point. Later, Susumu Kitagawa in Japan showed that some MOFs change shape depending on what surrounds them, making them far more adaptable than earlier versions.

A striking feature of some MOFs is the amount of internal space they hold. A few grammes can have as much surface area inside as an entire football field. Because of that, they can act like storage pockets or selective filters.

Research labs have tried using them for gas storage, carbon dioxide trapping, pollution control and even as tiny reactors. But outside the lab, they have not yet gone mainstream, mainly because manufacturing remains expensive and long-term durability has not been proven in real-world conditions.

One proposed use that has caught the most public attention is collecting water directly from the air. Some MOFs can hold water vapour even when humidity is low and then release it when heated, sometimes using only sunlight.

Tests carried out in desert areas such as the Mojave have shown that small, decentralised MOF-based setups can provide a few litres of drinking water per day. That may not solve large urban demand, but it might matter in places that have no reliable groundwater, no piped supply and limited power.

This idea becomes relevant when looking at India’s growing water distress. Rajasthan, Gujarat and parts of Maharashtra continue to struggle with groundwater decline, dry borewells and unpredictable monsoon cycles. In many villages, drinking water arrives by tanker and that too not on fixed schedules.

The problem extends beyond the shortage. In several districts of Rajasthan, lab tests by government and independent researchers have recorded fluoride, uranium and nitrate levels above safety guidelines. Many households know the water tastes different or stains surfaces, but long-term health risks are rarely discussed in public forums. Chlorination by-products have also started to appear, but monitoring is limited.

If technologies based on MOFs become stable and affordable, they could be tested in smaller communities where traditional water systems are failing or cannot be expanded economically. Such trials would likely suit desert border districts, scattered settlements or areas where migration for water has become seasonal. Solar-powered units would be more realistic than grid-powered ones, given the erratic electricity supply in many interior locations.

This discussion should not overlook the existing knowledge of people in Rajasthan and other arid regions. Traditional water harvesting systems like johads, kunds, baoris, beris, paar structures and taankas have been built, repaired and managed by communities for generations.

They have worked because they are simple, based on local climate, and need no specialised parts. But weather changes, population growth and contamination now stretch them beyond capacity in several locations.

A combination of old and new methods might work better than replacing one with the other. For example, a taanka that once stored rainwater could also collect supplementary water from a small MOF-based unit during prolonged dry months.

India has enough scientific capacity to explore this field further. IITs, IISc, CSIR labs and a few new deep-tech start-ups are already working on advanced materials. What remains unclear is how these materials will be produced at scale, at what cost and who will maintain the devices in the field.

Cost of replacement parts, service visits, and material lifespan will matter much more to users than theoretical efficiency numbers. Many promising technologies have failed not due to poor science, but because they were designed without field realities in mind.

The Nobel Prize has put MOFs in the news, but they are still at an early stage for practical rollout. Science has moved forward, but field-level engineering, community participation and long-term testing still need to catch up.

If the technology becomes affordable, rugged and easy to repair, it may offer an option for regions facing persistent water scarcity and pollution. For now, MOFs remain an interesting development whose future depends not only on laboratories, but also on villages, policy budgets and everyday usage patterns.

Abhijay A is a policy analyst, columnist and independent researcher. Sruthi Sreekumar is a junior research fellow with the department of chemical engineering and materials science at the Amrita Vishwa Vidyapeetham in Coimbatore. Views expressed are the authors’ own and don’t necessarily reflect those of Down To Earth.