Shana's Henna Bangalore
  • Home
  • Gallery
  • About Shana’s Henna
  • Contact

Monthly Archives: July 2021

Korean scientists may have found a way to desalinate seawater faster

Posted on July 11, 2021 by iqu

Nanofiber Membrane Filters 99.9% of Salt from Seawater within Minutes

The nanofiber membrane upheld a 99.9% salt rejection rate for a month.

Ameya Paleja

By  Ameya Paleja

Jul 06, 2021

 

 

 

 

 

 

 
Nanofiber Membrane Filters 99.9% of Salt from Seawater within Minutes

Schematic of the electrospinning device used to make this nanofiber membraneElsevier

The World Health Organization estimates that over 785 million people lack a clean source of drinking water. Even though 71 percent of the Earth’s surface is covered by seawater, we cannot drink this water. Scientists around the globe have been working to find efficient ways to desalinate seawater cheaply. Now, a team of Korean scientists may have found a way to do it in minutes. 

Freshwater, needed for most human activities accounts for only 2.5 percent of the total water available on the planet. Changing climate conditions are resulting in changes in precipitation and dry rivers, prompting countries to declare water shortages for the first time in their history. It is hardly surprising that desalination of seawater is the easiest way to address this issue. But these processes have their own limitations. One such limitation is membrane wetting. 

This Spring-Loaded Screw Is the Future of SoundproofingBuild a Nerf Gun From Nothing More Than CardboardSouth Korean Toilet Allows Students to Pay With Their PoopRichard Branson Is on His Way to Space. Watch It HappenWhat We Know and What We Don't: Autoimmune Illnesses and the Big UnknownIn Yet Another Antitrust, Google Is Being Sued by 37 US States Over Google Play

 

When using membranes to filter seawater, the membrane must remain dry for long periods of time. If the membrane becomes wet, the filtration process becomes ineffective and allows large amounts of salt to pass through the membrane. For long term operations, progressive membrane wetting has been observed regularly, which be resolved by changing the membrane. 

Researcher Yunchul Woo and his team at the Korea Institute of Civil Engineering and Building Technology (KICT) have now developed a membrane that is less susceptible to wetting and is stable in the long term.

The membrane is made of nanofibres that have been fabricated into a three-dimensional hierarchical structure, This was achieved by using a type of nanotechnology called electrospinning. Using this technology, the researchers were able to fabricate a membrane that is highly hydrophobic — i.e. water repellent. 

 

The hydrophobic nature of the membrane is helpful because it is designed to not allow water molecules to pass. Instead, a temperature difference is applied on the two sides of the membrane that causes water from one end to evaporate into water vapor. The membrane allows water vapor to pass, which then condenses onto the cooler side. Called, membrane distillation, this is a commonly used method of desalination using membranes. Since the salt particles are not converted to the gaseous state, they are left out on one side of the membrane, giving highly purified water on the other side. 

The Korean researchers also used silica aerogel in their membrane fabrication process which further enhanced the flow of water vapor through the membrane, providing quicker access to desalinated water. The team tested their technology for continuous operation for 30 days and found that the membrane continued to filter out 99.9 percent salt without any wetting issues.  

 

The research study was published in the Journal of Membrane Science

Posted in Uncategorized | Leave a comment |

New Chinese technology combines wood, bacteria, sunlight to purify water

Posted on July 10, 2021 by iqu

New technology combines wood, bacteria, sunlight to purify water

By

Brooks Hays
 
The new water-purification device features a top layer of light-absorbing carbon nanotubes, a middle layer of insulating glass bubbles and a bottom layer water-transporting wood. Photo by Qing-Fang Guan, et al. / Nano Letters 2020

 
The new water-purification device features a top layer of light-absorbing carbon nanotubes, a middle layer of insulating glass bubbles and a bottom layer water-transporting wood. Photo by Qing-Fang Guan, et al. / Nano Letters 2020

July 8 (UPI) — Engineers have developed a new wood-based steam generator that can purify water using bacteria-produced nanomaterials and the sun’s energy.

Solar steam generators, which use the sun’s energy to separate water molecules from contaminants via evaporation, aren’t new, but the quest to make the technology as efficient as possible is never-ending.

 

When working to improve upon solar steam generators, scientists can focus one or more sources of inefficiencies: light absorption, heat management, water transport or evaporation.

Researchers at the University of Science and Technology of China developed a water purification device that improves on all four processes.

RELATEDWater recycling can reduce pressure of urban usage on fresh water resources

 

The team of scientists selected wood for its sustainability, and because its porosity allows for rapid water transport. To bind the device’s wood layers, researchers relied on long cellulose nanofibers, which are produced by bacteria.

After sterilizing the wood, scientists applied the bacteria strain Gluconacetobacter xylinus and allowed it to ferment on the back of a block of wood. Next, researchers sprayed on a layer of aerosolized glass bubbles, an excellent insulator.

“The glass bubbles became embedded in the cellulose nanofibers produced by the bacteria, forming a hydrogel,” researchers explained in a news release.

RELATEDNew material expands by a factor of 100 when electrocuted

 

The cellulose nanofibers formed by the bacteria worked to bind together layers of the device together. To complete the device’s light absorbing top layer, researchers applied carbon nanotubes, which became intertwined with the cellulose nanofibers.

The device — detailed Wednesday in the journal Nano Letters — works by pulling and filtering water up throw the wood layers to the light absorbing top layer, which is heated by the sun. The purified water evaporates and is collected and condensed above and funneled to a holding tank.

The carbon nanotubes and cellulose nanofibers lower the energy required for water vaporization, while the layer of glass bubbles ensure the sun’s energy doesn’t dissipate down through the wood layers.

RELATEDNew catalytic reactor turns CO2 into liquid fuel

 

In addition to being constructed using relatively cheap and sustainable materials, the device boasts a higher evaporation rate and greater efficiency than most current solar steam generators.

The simple technology could be used to purify seawater, as well as contaminated lake and river water, in remote locations and in parts of the developing world.

RELATEDNew solar panel produces electricity and clean water
Posted in Uncategorized | Leave a comment |

Recent Posts

  • STARVING AFGHANS USE CRYPTO TO SIDESTEP U.S. SANCTIONS, FAILING BANKS, AND THE TALIBAN
  • Darul Uloom Deoband’s Stand About Maulana Saad Kandhlawi of Nizamuddin
  • Tablighi Jamat, The Powerful Muslim Revivalist Movement of 20th Century, at Crossroads
  • Everything You Need to Know About Avocados
  • Eye drops could replace reading glasses for millions

Recent Comments

  • A WordPress Commenter on Hello world!

Archives

  • January 2022
  • December 2021
  • November 2021
  • October 2021
  • September 2021
  • July 2021
  • June 2021
  • May 2021
  • August 2020

Categories

  • Uncategorized

Meta

  • Log in
  • Entries feed
  • Comments feed
  • WordPress.org

CyberChimps WordPress Themes

© Shana's Henna Vattamkulam, Edappal and Bangalore