Jul 292017

Plain quartz fiber, top, gains the ability to remove toxic metals from water when carbon nanotubes are added, bottom. The filters absorbed more than 99 percent of metals from test samples laden with cadmium, cobalt, copper, mercury, nickel and lead. Once saturated, the filters can be washed and reused. Courtesy of the Barron Research Group

Rice shows reusable, carbon nanotube-reinforced filters clean toxins from water

Carbon nanotubes immobilized in a tuft of quartz fiber have the power to remove toxic heavy metals from water, according to researchers at Rice University.

Prize-winning filters produced in the lab of Rice chemist Andrew Barron by then-high school student and lead author Perry Alagappan absorb more than 99 percent of metals from samples laden with cadmium, cobalt, copper, mercury, nickel and lead. Once saturated, the filters can be washed with a mild household chemical like vinegar and reused.

The researchers calculated one gram of the material could treat 83,000 liters of contaminated water to meet World Health Organization standards — enough to supply the daily needs of 11,000 people.

The lab’s analysis of the new filters appears this month in Nature’s open-access Scientific Reports.

The robust filters consist of carbon nanotubes grown in place on quartz fibers that are then chemically epoxidized. Lab tests showed that scaled-up versions of the “supported-epoxidized carbon nanotube” (SENT) filters proved able to treat 5 liters of water in less than one minute and be renewed in 90 seconds. The material retained nearly 100 percent of its capacity to filter water for up to 70 liters per 100 grams of SENT, after which the metals contained could be extracted for reuse or turned into a solid for safe disposal.

While the quartz substrate gives the filter form and the carbon nanotube sheath makes it tough, the epoxidation via an oxidizing acid appears to be most responsible for adsorbing the metal, they determined.

An electron microscope image shows quartz fibers with carbon nanotubes grown in place.

An electron microscope image shows quartz fibers with carbon nanotubes grown in place. Courtesy of the Barron Research Group

Alagappan, now an undergraduate student at Stanford University, was inspired to start the project during a trip to India, where he learned about contamination of groundwater from the tons of electronic waste — phones, computers and the like — that improperly end up in landfills.

“Perry contacted me wanting to gain experience in laboratory research,” Barron said. “Since we had an ongoing project started by Jessica Heimann, an undergraduate who was taking a semester at Jacobs University Bremen, this was a perfect match.”

Barron said the raw materials for the filter are inexpensive and pointed out the conversion of acetic acid to vinegar is ubiquitous around the globe, which should simplify the process of recycling the filters for reuse even in remote locations. “Every culture on the planet knows how to make vinegar,” he said.

“This would make the biggest social impact on village-scale units that could treat water in remote, developing regions,” Barron said. “However, there is also the potential to scale up metal extraction, in particular from mine wastewater.”

Learn more: Heavy metals in water meet their match


The Latest on: Toxic heavy metals
  • Known for toxic algae, Utah Lake could become a housing development for half a million people
    on January 22, 2018 at 5:16 am

    But in recent years it has been plagued by toxic algal blooms spreading across the surface ... A steel mill began discharging heavy metals there, too, and contamination from nearby farms seeped downstream (and continues to today). Because the lake is ... […]

  • Is Eating Raw Fish Safe? Man Pulls 5-Foot Tapeworm From Body After Eating Sushi
    on January 21, 2018 at 6:01 pm

    Listeria infection, although rare, may cause fetal death in pregnant women. There are also fish species that contain high amounts of pollutants and toxic heavy metals. Mercury content is high in tilefish, king mackerel, swordfish, marlin, and tuna. […]

  • Stuck in metal dust town, Sawol
    on January 16, 2018 at 5:50 pm

    battling with toxic air as they go about their daily lives. Now they are demanding that the central government step in to fix their plight. By Ko Dong-hwan SAWOL, Incheon ― This town is busy with the heavy traffic of dump trucks. The roads are dusty and ... […]

  • Renewable energy: Green solutions that use toxic heavy metals create their own environmental problems
    on January 12, 2018 at 6:00 am

    SOLAR energy is such a simple and elegant solution for Queensland. We have an abundance of sunlight and the popularity of solar panels has seen the cost fall dramatically, making them competitive with the coal- and gas-fired generation that has supported ... […]

  • Firefighter Heavy Metal Exposure & Cancer
    on December 1, 2017 at 5:33 am

    There has been a lot of talk about cancer in the fire service lately. After researching this subject, it is apparent that exposure to toxic heavy metals from smoke, contaminated flood waters, and a process known as toxic “hand-off” has been overlooked. […]

  • Toxic heavy metals in residents near mine
    on August 27, 2017 at 6:00 pm

    A REPORT on the health impacts has confirmed that people living near a gold mine in Phichit province have been exposed to higher than average levels of heavy metals. The study found that many samples of blood and urine showed exposure to dangerous levels ... […]

  • New toxic heavy metal issue for Portland: cobalt
    on June 8, 2016 at 10:27 am

    Three areas in Portland had much higher concentrations of the toxic element cobalt than in other parts of the city, the U.S. Forest Service revealed in a report released Tuesday. The findings on cobalt are the latest in a litany of disclosures about heavy ... […]

  • Heavy metals a toxic load
    on May 14, 2016 at 5:00 pm

    In today’s world we are exposed to numerous toxins on a daily basis. Heavy metals are a part of that toxic load. Some of the heavy metals are essential to our normal daily functioning, but in excess amounts they cause health problems. Other heavy ... […]

  • Heavy toxic metals detected in kids
    on February 13, 2016 at 3:42 am

    Researchers have detected heavy toxic metals in the body of special children in Punjab. This was revealed after a German laboratory tested the urine samples of 120 autistic children from different parts of the state. Lead was found to be high in 93 of 120 ... […]

  • How Do the Organisms Cope with the Toxic Heavy Metals?
    on March 23, 2007 at 8:50 am

    Sometimes, these contaminations lead to ecological catastrophes. But some organisms are able to resist and live in the conditions of high level accumulations of toxic heavy metals in their environment and even inside their bodies. Snails, for example ... […]

via Google News and Bing News

Other Interesting Posts

Leave a Reply

%d bloggers like this: