Tuesday, June 27, 2023

Don't wait, desalinate: A new approach to water purification

Good news! Desalination is salvation! Desalination is without doubt another one of the most important research areas for humanity!

"... To save energy, the researchers streamlined the salt separation process with a chemical phenomenon called a redox reaction. The word redox is a portmanteau of the words reduction (which, in chemistry, describes adding electrons to create a negative charge) and oxidation (which means subtracting electrons to create a positive charge). Physically, triggering a redox reaction looks like adding a special polymer-based material to the wastewater before it’s filtered and purified.
Chemically, the results are transformative. Instead of splitting water molecules into positively and negatively charged slices to coax out the salt, the redox reaction changes the charge of the entire water molecule in one fell swoop, achieving the same degree of salty separation with about 90% less energy than traditional water-splitting. ...
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"... electrodialysis. Just like dialysis of the blood, which, kidney-like, flushes salt and other toxins from our veins, electrodialysis removes salts and organic matter from wastewater to produce a clean, drinkable product. ..."

From the abstract:
"Robust, energy-efficient separation technologies for desalination and the removal of organic contaminants are critical in addressing growing concerns about water shortage and water pollution. Here, we propose a generalized strategy for advancing electrodialysis technologies using redox-flow concepts, by implementing a water-soluble redox-copolymer, poly(ferrocenylpropylmethacrylamide-co-[2-(methacryloyloxy)ethyl]trimethylammonium chloride), P(FPMAm-co-METAC), to eliminate the need for anion-exchange membranes (AEMs) and deploy cheaper and more robust nanofiltration membranes (NFs). The effective membrane retention of the redox material and stable redox activity facilitate the continuous desalination of various source waters, including brackish water, seawater, and wastewater, to produce potable water and remove organic contaminants without membrane fouling or polymer crossover. Leveraging the reversible redox reaction of ferrocene reduces energy consumption by 88% within a single-unit cell compared to conventional ED. In addition, utilizing reusable redox-copolymer and cost-effective NFs promotes economic feasibility, achieving a water production cost of $0.13 m–3. Overall, the combination of redox-copolymer in flow and NFs provides a new avenue to address water contamination caused by organic pollutants and water scarcity in an energy efficient manner."

Don't wait, desalinate: A new approach to water purification

Don’t wait, desalinate: the electrified future of clean water (primary news source) A water purification system developed by Beckman researchers separates out salt and other unnecessary particles with an electrified version of dialysis. Successfully applied to wastewater with planned expansion into rivers and seas, the method saves money and saps 90% less energy than its counterparts.

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