The energy source hydrogen, obtained using electricity from renewable sources, could serve as the cornerstone of a new CO2-neutral energy supply. “However, the current state of technology requires water of drinking quality for this type of electrolysis – an increasingly expensive commodity globally,” says a statement from the TU Berlin. Peter Strasser, head of the Technical Chemistry department, and colleagues have published a study on the possibilities of electrolysis of salt water in the journal “Nature Energy”.
Arid areas in particular that potentially have sufficient solar energy are often close to oceans, but “as a rule suffer from a striking lack of fresh water,” according to the scientists. “The purification of salt water, in turn, is a cost-intensive and CO2-intensive process, which makes the process uneconomical and, above all, no longer climate-neutral.” Researchers around the world are working on developing a technology that is able to “immediately convert salt water into... “To split hydrogen and oxygen without a previous desalination step,” explains Peter Strasser. The energy source obtained in this way can then be transported “directly in the form of liquid hydrogen, but also after further local conversion into synthetic liquid methane or synthetic gasoline on ships or in pipelines throughout the world, thereby facilitating the transition to a hydrogen-based energy infrastructure.”
On the one hand, research should focus on the use of novel catalyst materials, but also on suitable membranes. The membranes commonly used in electrolysis are “often unable to block the salt impurities in the water”. One “potentially interesting approach” is the use of membranes that are modeled on those in certain plants such as mangrove roots. These plant membranes could filter seawater. “If similar membranes were used in technical electrolysis, the salt concentration on the surface of the catalytic electrodes could be reduced and membrane contamination could be reduced.”
Deep link:
https://www.pressestelle.tu-berlin.de/menue/tub_medien/publikationen/medieninformationen/2020/mai_2020/medieninformation_nr_782020/
https://www.nature.com/articles/s41560-020-0550-8
Photos:
Mangroves can filter salt water - scientists want to research whether such plant membranes are suitable for using salt water instead of drinking water for electrolysis / (c) Unesco
