MIT's breakthrough: water evaporation by light For centuries we have understood evaporation as a process caused by heat. Sunlight heats...

MIT's breakthrough: water evaporation by light

For centuries we have understood evaporation as a process caused by heat. Sunlight heats the water and the molecules gain energy. They escape into the air as vapor. But new research from the Massachusetts Institute of Technology challenges this long-held belief. Their results show that under certain conditions, light can bypass heat and evaporate water directly.

While studying hydrogels, jelly-like substances that hold enormous amounts of water, something surprising happened. The researchers observed a faster rate of evaporation than could be explained by thermal energy alone. Intrigued, they began a series of experiments and simulations.

Their setup involved monitoring hydrogels exposed to different colors of light. They carefully monitored weight loss due to evaporation. The results were amazing. In fact, light caused evaporation regardless of heat. This effect, called the photomolecular effect, was most effective when using green light, further strengthening the non-thermal coupling.

Why is this discovery important?

Traditional desalination relies on boiling seawater, an energy-intensive process. This photo-activated method has the potential to be even more efficient as sunlight is used in a sustainable desalination solution.

Imagine this: desalination plants run using the very sunlight they target!

The results go beyond desalination. Water purification, wastewater treatment and even irrigation systems can benefit from a new understanding of light-matter interactions. Researchers envision scenarios in which evaporation from sunlight could purify polluted water or remove excess moisture from agricultural runoff.

Of course, this is an early discovery, so many questions remain. The exact mechanism of the photomolecular effect is still being studied. Is it possible to effectively reproduce this phenomenon outside of hydrogels, for example in open water? Additional research is needed to exploit the full potential of this groundbreaking technology.

MIT research provides a glimpse into a future where sunlight plays a dual role:

Illuminating the world and providing innovative solutions for water management. This is a testament to scientific curiosity and the ability to question established assumptions. As research progresses, we may see a paradigm shift in how we interact with and use our most important resource: water.