Improved Process for Making Clean Drinking Water Out of Salt Water Developed

It would be helpful in creating much more safe drinking water if it actually becomes mass produced.

Using an innovative combination of sunshine and hydrogels, a new device just unveiled by scientists is able to produce clean drinking water from virtually any source – even the salty waters of the Dead Sea.

This new technique could prevent tens of thousands of death every year, since access to safe drinking water is at a premium in many developing nations, not to even mention the wake of a natural disaster or emergency anywhere in the world.

The technology is compact, inexpensive, and uses ambient solar energy in order to evaporate water and remove impurities, making it a substantial upgrade over similar processes that have been used in the past.

“Water desalination through distillation is a common method for mass production of freshwater,” says one of the researchers, Fei Zhao from the University of Texas at Austin.

“However, current distillation technologies, such as multi-stage flash and multi-effect distillation, require significant infrastructures and are quite energy-intensive.”

“Solar energy, as the most sustainable heat source to potentially power distillation, is widely considered to be a great alternative for water desalination.”

The new filtering device works by combining several gel-polymer hybrid materials that mix both hydrophilic (water-attracting) and semiconducting (solar-adsorbing) properties.

The nanostructure of the gels enables more water vapour to be produced from less solar energy, and without the complicated series of optical instruments that existing devices use to concentrate sunlight. Here, that concentration isn’t needed.

When a jar of contaminated water is placed in direct sunlight with the hydrogel evaporator on top, vapour is released that’s then trapped and stored by a condenser.

“We have essentially rewritten the entire approach to conventional solar water evaporation,” says lead researcher Guihua Yu, from the University of Texas at Austin.

To give their new contraption a thorough testing, the researchers tried it out at the Dead Sea, which borders Israel, the West Bank, and Jordan. With a salinity of around 34 percent, it’s about ten times as salty as your standard ocean water.

The hydrogel filtering device passed its test with flying colours, producing drinking water from the Dead Sea that met the accepted drinking water standards put down by the World Health Organisation (WHO) and the US Environmental Protection Agency (EPA).


New Desalination Process is Potentially Cheaper

It’s difficult to find a lot of good news on some days, but I try to look for the most relevant developments of it. The access to clean drinking water is set to become a bigger problem than it is now, and that’s with the ocean being about a third of the Earth. An efficient desalination process is needed to make use of the immense water of the ocean, especially when freshwater is roughly 3 percent of water in the world.

Engineers at the University of Illinois have taken a step forward in developing a saltwater desalination process that is potentially cheaper than reverse osmosis and borrows from battery technology. In their study, the researchers are focusing on new materials that could make desalination of brackish waters economically desirable and energy efficient.

The need for practical desalinization technology is rising in the context of global climate change. Coastal regions, where the rise of seawater could encroach upon and contaminate groundwater aquifers, present just one area of concern. As demand for diminishing clean water sources increases, the need for desalination of lower-salinity brackish water from inland and industrial sources will increase, the researchers said.

Illinois mechanical science and engineering professor Kyle Smith and his co-authors have published a study demonstrating the viability of this batterylike technology in the journal Electrochimica Acta.

In a previous study, Smith and his co-authors used theoretical modeling to show that technology used in sodium-ion batteries may efficiently desalinate seawater. Their theory states that by using electrodes that contain sodium and chloride ions, salt is drawn out and held in a chamber separate from the purified water.