By Dr. Rita Evelyne Joshua, Publishing Associate: Researcher and Writer at Save the Water™ | October 24, 2025

Edited by Chase Day O'Donnell, Publishing Intern at Save the Water™ and Joshua Awolaye, Publishing Associate: Editor at Save the Water™

Water is the elixir of life. We get it from fresh water sources such as lakes, rivers and ground water. Desalination processes can also turn saltwater into drinking water. As well as this, a novel approach called atmospheric water harvesting (AWH) extracts water straight from the air. 

This article highlights how MIT researchers used sorbent-based water harvester to harvest water from air using self-powered, window-sized devices. These devices contain sorbent hydrogel that extracts water from the humidity present in  air. This technology offers a way to produce water even in desert regions. 

What is Atmospheric Water Harvesting (AWH)?

AWH is a decentralized process. It pulls water from the moisture in the air. This makes it a sustainable and eco-friendly way to get fresh drinking water. Reliable water harvester AWH should be energy efficient, stable, and perform well.

Water harvesters fall into two groups: active and passive cooling methods.

1. Active Cooling Method

This uses energy such as heat, electricity, pressure, or renewable energy to condense water from the atmosphere.

2. Passive Cooling

It doesn’t use external energy. It uses natural processes like absorption, radiation etc. The following methods are commonly used to produce water

• Dew harvesting- Devices called Dew Harvesters collect small water droplets through a natural process. They work best when humidity is above 40%.‍
• Fog AWH- Mesh or net-like structures collect fog particles of 1- 30 μm. Gravity helps gather water on these meshes.
• Membranes and sorbents- Sorbents like silica gel, hydrogels, metal-organic complexes and membranes extract water in the atmosphere.

Sustainable Water Harvester Using a Sorbent Developed by MIT

A team of MIT researchers designed an efficient, passive AWH system that works under low humidity and dry conditions. The window-like structure has a vertical sorbent panel that absorbs water at night and releases it in the morning. The whole process sustains itself. The team conducted experiments in Death Valley, California, which is known for its dry weather. The system produced 57 to 161.5 ml of water per day at humidity levels of 21% to 88%. This device outperformed other water harvesters at low humidity, making it an ideal water harvester for desert regions.

The Major Components:

‍1. Glass Chamber

This contains sorbent enclosed in cooling glasses. The team painted the glasses with cooling material. After that, the team used the sun’s heat to evaporate the water during the day. The water then condenses on the cooling glasses.

‍2. Sorbent

The team designed a hydrogel-based water harvester, which is  arranged in a dome shape, like black bubble wrap. They made it from polyvinyl alcohol (absorbs water), lithium chloride or LiCl (attracts moisture), and glycerol (prevents lithium ions from mixing with water). This sorbent can grow to about 10 times its volume by absorbing humidity.

Advantages of AWH

• AWH harvests water in places with little rain. When combined with solar energy, it can be used in irrigation, defense operations etc.
• It works in areas with wide temperature and humidity fluctuations.
• It can supply clean water in areas hit by natural disasters such as earthquakes and flooding.

Challenges and Future of AWH

Several markets offer active AWH generators. However, researchers are still working on finding eco-friendly, long-lasting passive AWH systems.

Researchers focus on the following areas:

• Design optimization – Researchers study ways to enhance how much water sorbents can absorb.
• Energy supply – They develop hybrid models that use renewable energy like solar and wind to extract water from sorbents.
• New sorbent materials – Scientists study how to synthesize sorbent materials with high absorption efficiency that can be used as water harvesters.
• Bio-mimicking – Researchers study structures adapted from nature to capture water from air.

In conclusion,  AWH offers great potential to address global water shortages. This sustainable technology takes clean water straight from the air, even in dry regions with low humidity.