Cheap gel membrane creates 13 liters of water from the air every day

Water scarcity is a big problem for the world and devices that draw water from the air can help solve this problem. A team at the University of Texas Austin has developed a low-cost gel membrane capable of drawing large amounts of water each day from the air, including dry air. New research published in the journal Nature Communications May 19th.

The gel consists of two main ingredients, cheap and common: cellulose – obtained from the cell walls of plants – and konjac gum – a widely used food additive. These two ingredients combine to form a gel film that can absorb water from the air, then release it when needed without much energy.

First, the porous structure of konjac gum causes water in the surrounding air to condense. Meanwhile, cellulose will react with heat by transitioning to a hydrophobic state, releasing the resulting water.

Making the gel is relatively simple, the team says. The basic ingredients are mixed together then poured into a mold, left to stand for two minutes. Next, the mixture is freeze-dried, separated from the mold and ready to use. Basically, the mixture can be molded into whatever shape it needs and scaled up fairly easily and at low cost.

The gel membrane proved to be very effective in the team’s tests. At 30% relative humidity, one kilogram of gel can produce 13 liters of water per day. When the humidity drops to just 15%, a low level even in desert air, one kilogram of gel can still produce more than six liters of water per day.

The efficiency of the new gel film can be further improved by making absorbent layers, thicker films, or other forms of the material, the team of experts say. The important thing is that the material is very cheap, costing only about 2 USD per kg to make. This is a key factor in scaling up and bringing new technology to remote areas as well as developing countries.

Thu Thao (According to New Atlas)