Utilization of plasma in water desalination and purification

© 2020 Elsevier B.V. Supplying fresh drinking water to the world population is a persistent global challenge. Therefore, effective and efficient desalination processes are becoming increasingly important. Oceans account for most of the water on Earth and the presence of salts and other contaminants in seawater prevents them from being used as a source of drinking water. Owing to this challenge, non-thermal plasma can be utilized in order to enhance the existing desalination processes via membrane or material modification while it can also be used as a direct tool for seawater desalination leading to significant process improvements. A direct non-thermal plasma-based desalination process is a new emerging area of research and recent efforts have shown its promise with many unexplored mechanisms, providing benefits that conventional desalination processes cannot offer. Here we critically review the use of plasma technologies in water desalination including membrane modification by plasma for pressure, thermal, photothermal processes and direct plasma-based desalination process. We also address the use of plasmas in water purification. Finally, the existing challenges and future prospects are outlined

Trends in the Prevalence of Dental Fluorosis in the United States: A Review

This paper assesses, by comparing recent published evidence with Dean's pioneering work, whether an increase in the milder forms of dental fluorosis may have occurred since Dean's time. To the extent that the crude comparisons of recent research with historic studies are valid, the data indicate a slight trend toward more fluorosis today than would be expected based upon findings in the late 1930s and early 1940s. This suggested increase in fluorosis is not as clear-cut nor as widely accepted as the recent decline in the prevalence of dental caries. Thus, further study of the prevalence of fluorosis and caries in relation to fluoride ingestion will be required to help validate the trend, and to allow dental researchers and decision makers to plan for the future.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66368/1/j.1752-7325.1987.tb01980.x.pd