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THIS MONTH'S FEATURE ARTICLE
Engineers will be called upon to find solutions for the challenges the world will face in the 21st century. These articles highlight the diversity of the work which continues in the search for those solutions.

Manganese May Be To Blame For Lead In Water
August 2019

Manganese is not a particularly toxic mineral. In fact, people need a little in their diets to remain healthy.

Research at Washington University in St. Louis has shown however, that in conjunction with certain other chemicals, naturally occurring manganese can lead to big changes in the water in lead pipes. Depending on what disinfectants are used in the water, those changes can have significant — even dangerous — consequences.

The results were recently published in Environmental Science and Technology.

According to information, the research focuses on a unique form of lead, PbO2 or lead dioxide (lead in the plus-4 oxidation state). Lead dioxide has a very low water solubility — it does not easily dissolve in water alone. It is also uncommon in nature, unlike the more familiar PbCO3, the lead carbonate that makes up the scales that tend to form on pipes.

“You don’t find PbO2 in the environment because there is no strong oxidizing agent,” said Daniel Giammar, the Walter E. Browne Professor of Environmental Engineering at the McKelvey School of Engineering. “But good disinfectants are often good oxidizing agents.”

Chlorine is a great disinfectant, so much so that it’s used commonly in drinking water in America and across the world. It is also good oxidizing agent and promotes the transformation of lead carbonate to lead dioxide.

It turns out, however, that the process isn’t particularly speedy, a fact that jibes with some real-world systems, but, seemingly, not with others.

“If you look at a system that has lead pipes and free chlorine, then you do the calculations, you’d expect that every single one would have lead dioxide on the pipes,” Prof. Giammar said. “But we don’t see that. It makes us think: Something else is influencing whether or not a particular system ends up with lead dioxide on its inner surface. That’s where manganese comes in.”

In the presence of oxidants, manganese can easily change oxidation states; if the manganese comes into contact with chlorine, it’s oxidized, turning into manganese oxide. Both in computer models and in experiments that mimicked water pipes — complete with artificial tap water —Prof. Giammar’s lab found the manganese oxide acted as a catalyst, increasing the rate of conversion from lead carbonate to lead dioxide by two orders of magnitude.

“The chlorine is still the reactant that’s driving the lead conversion, but the manganese oxide acts as a catalyst to make it faster,” Prof. Giammar said.

This research may well help inform the way other chemical interactions affect rates of lead transformation. “What other things that aren’t lead may be affecting these rates?” Prof. Giammar asked. “Do iron oxides do it? Aluminum is something we’ll study, too.”

Further research into understanding what reactions influence lead transformation rates and otherwise affect the availability of lead in water will lead to more than breakthroughs in the lab. They will have real implications on health.



Feature Articles
Below are listed the 12 most recent Feature Articles.
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Manganese May Be To Blame For Lead In Water
August 2019

Research at Washington University in St. Louis has shown however, that in conjunction with certain other chemicals, naturally occurring manganese can lead to big changes in…

Large “Dead Zone” Forecasted For Chesapeake Bay
July 2019

This year, exceptionally high spring rainfall and streamflow is transporting nitrogen to tidal waters in amounts above the long-term average…

Materials Explorers™ Program Adds New STEM Resources
June 2019

The Materials ExplorersSTEM outreach program recently launched its newest classroom activities for high school students through…

New Potential Pollutants In Waterways Studied
May 2019

When you flush the toilet, you probably don’t think about the traces of the medicine and personal care products in your body that are winding up in…

Researchers Study Waste Form Corrosion
April 2019

Although glass, ceramics, and metal forms have been around for ages, researchers don’t yet know key details about how materials crumble, dissolve, or otherwise come undone.

Technology Protects The Power Grid By Hacking Would-be Hackers
March 2019

Milos Manic, Ph.D., professor of computer science and director of VCU’s Cybersecurity Center, along with colleagues at the Idaho National Laboratory (INL), has developed a protection system that…

NASA’s Webb Telescope To Study Cosmic Jets and Stellar Outflows
February 2019

Webb’s exquisite angular resolution will allow it to pick up the tiniest details.

High-Tech Heating Patches Created
January 2019

What if, instead of turning up the thermostat, you could warm up with high-tech, flexible patches sewn into your clothes – while significantly reducing your electric bill and carbon footprint?

Virginia Tech Innovation Campus Helps Attract Amazon
December 2018

Virginia Tech is making a historic commitment to build a revolutionary 1 million-square-foot, technology-focused campus in Alexandria…

Improving Smart-Window Energy Efficiency With Nanoparticles
November 2018

U.S. buildings leak an estimated 30 percent of their energy through inefficient windows, costing consumers an estimated $42 billion annually.

Biosensor Technology For Wearable Devices Invented
October 2018

Engineers have created a smart wristband with a wireless connection to smartphones that will enable a new wave of personal health…

Parker Solar Probe Launched On Historic Journey
September 2018

Hours before the rise of the very star it will study, NASA’s Parker Solar Probe launched from Florida Sunday, August 12th, to begin its journey to the Sun, where it will undertake a landmark mission.


Feature Article Archive
 
 
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