According to widely accepted knowledge, lakes and rivers are main sources of fresh water for most people on the Earth. But, lakes and rivers make for only 0.007% of the water available in the world. With the growing human population, the need for fresh water has grown multiple times. So much so, every two out of three people in the world experience extreme scarcity of water at least one month in a year.
To address this, other sources of water such as seawater and wastewater could be used to serve the increasing water needs. Seawater and wastewater, however, contain salt and contaminants such as toxic metals in high concentrations.
To find a solution for this, scientists and engineers have developed methods to eliminate salts and toxins from water via desalination. On the downside, currently available options are expensive and energy-intensive, particularly because of a large number of steps to be carried out. Moreover, currently available desalination techniques create lot of waste. So much so, approximately half of the feedstock water in desalination plants is lost as wastewater that contains all the removed salts and toxins.
Meanwhile, to construct a single filter capable of capturing both metals and remove salts, this needed a material to remove many different contaminants, says one of the researchers. To accomplish this, the research team switched to minuscule absorbent particles called permeable aromatic frameworks. The design of the particles is such to catch individual contaminants. For example, one absorbent particle designed specifically to capture only mercury. Some other absorbent particles to capture iron, copper, or boron. Later, the four different types of particles implanted into thin plastic membranes to catch contaminants according to the type of particle.