Desalination Breakthrough Turns Seawater Into Drinking Water
Turning seawater into drinking water just became more feasible. Scientists at the University of Manchester in the UK have developed graphene oxide membranes with holes small enough to filter out salt. The sieves represent a technological breakthrough in the effort to make desalination more efficient and affordable.
Graphene oxide membranes have been used in desalination experiments for years, but never before has the sieve been small enough to filter out smaller particles.
One of the major challenges with this process is the natural tendency of graphene oxide membranes to swell in water. This causes their pores to expand, and salt particles to pass through. The scientists, led by Rahul Nair, were able to control the swelling by building epoxy resin walls around the membranes, as noted in the study published in Nature Nanotechnology.
"Realization of scalable membranes with uniform pore size down to atomic scale is a significant step forward and will open new possibilities for improving the efficiency of desalination technology," Nair said. "This is the first clear-cut experiment in this regime. We also demonstrate that there are realistic possibilities to scale up the described approach and mass produce graphene-based membranes with required sieve sizes."
According to the International Water Association, thousands of desalination plants currently exist worldwide, but the process remains expensive.
Earth's oceans contain 97 percent of the planet's water, the National Ocean Service estimates. To paint a picture of the total amount of salt in the oceans, NOAA said that "if the salt in the ocean could be removed and spread evenly over the Earth's land surface, it would form a layer more than 500 feet thick, about the height of a 40-story office building."
According to a United Nations report:
• Around 700 million people in 43 countries suffer today from water scarcity.
• By 2025, 1.8 billion people will be living in countries or regions with absolute water scarcity, and two-thirds of the world's population could be living under water stressed conditions.
• With climate change, almost half the world's population will be living in areas of high water stress by 2030.
In an article accompanying the scientists' research, Ram Devanathan, from the Pacific Northwest National Laboratory, said the next step toward scaling the desalination process would be to test the durability of the graphene oxide membranes.
"The selective separation of water molecules from ions by physical restriction of interlayer spacing opens the door to the synthesis of inexpensive membranes for desalination," Devanathan said. "The ultimate goal is to create a filtration device that will produce potable water from seawater or wastewater with minimal energy input."
The World Health Organization (WHO) announced Monday that 64 high-income nations have joined an effort to distribute a COVID-19 vaccine fairly, prioritizing the most vulnerable citizens, as Science reported. The program is called the COVID-19 Vaccines Global Access Facility, or Covax, and it is a joint effort led by the WHO, the Coalition for Epidemic Preparedness Innovations (CEPI) and Gavi, the Vaccine Alliance.
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EcoWatch Daily Newsletter
By Gloria Oladipo
In the face of dangerous heat waves this summer, Americans have taken shelter in air conditioned cooling centers. Normally, that would be a wise choice, but during a pandemic, indoor shelters present new risks. The same air conditioning systems that keep us cool recirculate air around us, potentially spreading the coronavirus.
Toxins in water produced by cyanobacteria was likely responsible for more than 300 elephant deaths in Botswana this year, the country's wildlife department announced on Monday.
How Did Cyanobacteria Poison the Elephants?<p>Cyanobacteria are microscopic organisms common in water and sometimes found in soil. Some cyanobacteria produce neurotoxins.</p><p>The cyanobacteria "was growing in pans" or watering holes, the principal veterinary officer of the Department of Wildlife and National Parks, Mmadi Reuben, told reporters.</p><p>Reuben said the deaths had "stopped towards the end of June 2020, coinciding with the drying of pans."</p><p>"However we have many questions still to be answered such as why the elephants only and why that area only? We have a number of hypotheses we are investigating," added Reuben.</p><p>Similar elephant deaths have also been recorded in neighboring Zimbabwe.</p>
Climate Change to Blame?<p>Not all cyanobacteria are toxic but scientists say varieties dangerous to humans and animals are occurring more frequently as climate change drives up global temperatures.</p><p>Southern Africa's temperatures are rising at twice the global average, according to the Intergovernmental Panel on Climate Change.</p>
Elephant Paradise?<p>Africa's overall elephant population is declining due to poaching. But Botswana, home to almost a third of the continent's elephants, has seen numbers grow to around 130,000.</p><p>Botswana's government said it was continuing studies into the occurrence of the deadly bacteria. In the winter, elephants hydrate themselves mainly by eating roots and bark, especially of the baobab tree.</p>
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By Alexandra Villarreal
As West coast wildfires color the skies dystopian red and orange and an aggressive hurricane season batters the U.S. Gulf coast, college students are demanding their schools take bold action to address the climate crisis.
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The National Hurricane Center has run out of names for tropical storms this year and has now moved on to the Greek alphabet during an extremely active hurricane season. Late Monday night, Tropical Storm Beta became the ninth named storm to make landfall. That's the first time so many named storms have made landfall since 1916, when Woodrow Wilson was president, according to NBC News.
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