News: Here is some potentially very positive news …
It’s estimated that nearly 800 million people globally today lack access to safe drinking water–that’s not positive; it’s a huge, dangerous problem.
Existing technologies “for purifying contaminated water and desalinating seawater” often are very expensive and use large amounts of energy–beyond the ability of many communities to put into place.
Solar stills are an existing lower-tech and less expensive alternative. The still uses sunlight to heat and then evaporate water separating the contaminants from the clean water (which condenses and is collected). But, the basic small still doesn’t produce a lot of clean water and has to be quite large in size to support the daily needs of a small family.
However, recent research may have begun to solve this challenge. Using hydrogels (multiple polymer mixtures including a polymer called chitosan), a basic solar still was able to distill “about 12 times the amount [of water] produced by today’s commercially available versions.” In other words, a small still could produce enough clean drinking water per day to serve the needs of a small family. And, “all three polymers in the hydrogel are both commercially available and cheap.”
Learn more: New solar technology could produce clean drinking water for millions in need (Robert F. Service, Science, 28 June 2019).
And, go to the source: Architecting highly hydratable polymer networks to tune the water state for solar water purification (Xingyi Zhou, et al., Science Advances, 28 June 2019).