Editorial: Separations for Energy and Environmental Applications

Climate change and global environmental impacts are challenging humanity as a whole, and particularly the scientific community, to rethink our approaches towards energy harvesting, storage, and utilization, and to formulate processes geared to restoring compromised environments. A large task in these efforts involves developing technologies that have low or no carbon footprint, enable the use of renewable energy sources, and minimize or eliminate contamination of water resources and generation of untreatable waste. At the heart of many manufacturing technologies lie separation processes ranging from the purification of raw materials and consumables to the treatment or reutilization of waste. Therefore, revolutionizing these technologies involves developing novel separation processes that align perfectly with environmentally conscious goals. The goal of this Research Topic titled “Separations for Energy and Environmental Applications” is to provide an avenue to disseminate critical review on the state-of-the art and original research articles on emerging separation processes thatwill support the formulation of new, environmentally conscious chemical technologies that enable the migration to renewable energy sources. The first article (Murphy and Haji) presents a review of technologies for direct lithium extraction from low concentration, lithium-ion aqueous solutions. Lithium has become a significant player in the energy landscape, as it is the main component of lithium-ion batteries and of nuclear fusion technologies. Since lithium-ion batteries enable the utilization of intermittent, renewable energy sources as wind and solar, and the substation of fossil fuels in transportation, the demand for lithium increases exponentially as we migrate towards sustainable energy technologies. However, lithium land reserves are finite. According to the review article, lithium land reserves will be depleted within the next 60 years given the rate of exploitation required to satisfy the growing demand. It is imperative to develop technologies capable of separating and enriching lithium-ion from dilute solutions, from seawater to geothermal fluids and mine runoffs, and the review article in the Research Topic provides a much necessary foundation on the state-of-the-art for researchers to tackle this challenge. The second article (Lee and Chung) in this Research Topic presents original research on the separation of lithium from low concentration, lithium-ion aqueous solutions, specifically geothermal fluid. The article focusses on the effect of silicate ions, ubiquitous in thermal fluids, on the yield of lithium during separation. This Research Topic is of particular interest, as it aims to enable the recovery of a valuable resource from aqueous waste generated during renewable, geothermal energy production. OPEN ACCESS