Water scarcity may not be a problem thanks in part to the invention of a team of experts at Monash University in Melbourne.
Australian scientists have developed a system to make sea water drinkable.
All through a hi-tech filter and direct sunlight in a process that takes less than 30 minutes. The filter, the experts explain, is able to transform hundreds of litres of drinking water a day thanks to the sun’s rays, through an energy efficient and economically sustainable process.
The MOF filter absorbs salt from the water without consuming energy; once filled with salt, it is placed in direct sunlight to regenerate, taking less than four minutes before being reused to desalinate the seawater.
Mof or metal-organic frameworks are “sponges” made at a molecular level, composed of metal ions connected together by organic materials.
Produced for the first time in 1995 in California, Mofs have as their main property a microporosity that allows them to be used to separate certain substances, such as water or carbon dioxide, since they act as a “sieve” that can divide the various components.
This microporosity changes according to the materials that make up the Mof and this allows it to filter molecules of different kinds, so that these devices can be used to purify the air from toxic substances.
From this we can understand why these devices are also interesting at an industrial level and why it is necessary to produce Mof at sustainable costs.
Construction of the first Mofs had already begun in 2014, using zirconium as the starting material. Since this metal is too expensive, studies have continued to try to make the “filters” with more affordable materials.
Huanting Wang, an expert in the chemical engineering department of the University of Monash and the main author of the study, explains how “desalination represents a possible solution to solve the increasingly serious crisis in the world, thanks to the unlimited amount of brackish water present on our planet”.
The World Health Organization indicates that good quality drinking water should have a total dissolved solid (TDS) of <600 parts per million (ppm).
With the designed device, researchers obtained drinking water from brackish water with a TDS level of <500 ppm in just 30 minutes and were able to regenerate MOF in four minutes in sunlight.
The MOF used for the experiment was called PSP-MIL-53 and resulted in 139.5 litres of fresh water per kilogram of MOF per day, with low energy consumption. This was achieved by desalinating 2,233 ppm of water from a river, lake or aquifer.