
-
Former pro-democracy Hong Kong lawmaker granted asylum in Australia
-
All Blacks beat Argentina 41-24 to reclaim top world rank
-
Monster birdie gives heckled MacIntyre four-stroke BMW lead
-
Coffee-lover Atmane felt the buzz from Cincinnati breakthrough
-
Coffe-lover Atmane felt the buzz from Cincinnati breakthrough
-
Monster birdie gives MacIntyre four-stroke BMW lead
-
Hurricane Erin intensifies offshore, lashes Caribbean with rain
-
Kane lauds Diaz's 'perfect start' at Bayern
-
Clashes erupt in several Serbian cities in fifth night of unrest
-
US suspends visas for Gazans after far-right influencer posts
-
Defending champ Sinner subdues Atmane to reach Cincinnati ATP final
-
Nigeria arrests leaders of terror group accused of 2022 jailbreak
-
Kane and Diaz strike as Bayern beat Stuttgart in German Super Cup
-
Australia coach Schmidt hails 'great bunch of young men'
-
Brentford splash club-record fee on Ouattara
-
Barcelona open Liga title defence strolling past nine-man Mallorca
-
Pogba watches as Monaco start Ligue 1 season with a win
-
Canada moves to halt strike as hundreds of flights grounded
-
Forest seal swoop for Ipswich's Hutchinson
-
Haaland fires Man City to opening win at Wolves
-
Brazil's Bolsonaro leaves house arrest for medical exams
-
Mikautadze gets Lyon off to winning start in Ligue 1 at Lens
-
Fires keep burning in western Spain as army is deployed
-
Captain Wilson scores twice as Australia stun South Africa
-
Thompson eclipses Lyles and Hodgkinson makes stellar comeback
-
Spurs get Frank off to flier, Sunderland win on Premier League return
-
Europeans try to stay on the board after Ukraine summit
-
Richarlison stars as Spurs boss Frank seals first win
-
Hurricane Erin intensifies to 'catastrophic' category 5 storm in Caribbean
-
Thompson beats Lyles in first 100m head-to-head since Paris Olympics
-
Brazil's Bolsonaro leaves house arrest for court-approved medical exams
-
Hodgkinson in sparkling track return one year after Olympic 800m gold
-
Air Canada grounds hundreds of flights over cabin crew strike
-
Hurricane Erin intensifies to category 4 storm as it nears Caribbean
-
Championship leader Marc Marquez wins sprint at Austrian MotoGP
-
Newcastle held by 10-man Villa after Konsa sees red
-
Semenyo says alleged racist abuse at Liverpool 'will stay with me forever'
-
In high-stakes summit, Trump, not Putin, budges
-
Pakistan rescuers recover bodies after monsoon rains kill 340
-
Hurricane Erin intensifies to category 3 storm as it nears Caribbean
-
Ukrainians see 'nothing' good from Trump-Putin meeting
-
Pakistan rescuers recover bodies after monsoon rains kill 320
-
Bob Simpson: Australian cricket captain and influential coach
-
Air Canada flight attendants strike over pay, shutting down service
-
Air Canada set to shut down over flight attendants strike
-
Majority of Americans think alcohol bad for health: poll
-
Hurricane Erin intensifies in Atlantic, eyes Caribbean
-
Louisiana sues Roblox game platform over child safety
-
Kildunne confident Women's Rugby World Cup 'heartbreak' can inspire England to glory
-
Arsenal 'digging for gold' as title bid starts at new-look Man Utd

US high schoolers design low-cost filter to remove lead from water
When the pandemic forced schools into remote learning, Washington-area science teacher Rebecca Bushway set her students an ambitious task: design and build a low-cost lead filter that fixes to faucets and removes the toxic metal.
Using 3D printing and high-school level chemistry, the team now has a working prototype -- a three-inch (7.5 centimeter) tall filter housing made of biodegradable plastic, which they hope to eventually bring to market for $1 apiece.
"The science is straightforward," Bushway told AFP on a recent visit to the Barrie Middle and Upper School in suburban Maryland, where she demonstrated the filter in action.
"I thought, 'We have these 3D printers. What if we make something like this?'"
Bushway has presented the prototype at four conferences, including the prestigious spring meeting of the American Chemistry Society, and plans to move forward with a paper in a peer-reviewed journal.
Up to 10 million US homes still receive water through lead pipes, with exposure particularly harmful during childhood.
The metal, which evades a key defense of the body known as the blood-brain-barrier, can cause permanent loss of cognitive abilities and contribute to psychological problems that aggravate enduring cycles of poverty.
A serious contamination problem uncovered in Flint, Michigan in 2014 is perhaps the most famous recent disaster -- but lead poisoning is widespread and disproportionately impacts African Americans and other minorities, explained Barrie team member Nia Frederick.
"And I think that's something we can help with," she said.
The harms of lead poisoning have been known for decades, but lobbying by the lead industry prevented meaningful action until recent decades.
President Joe Biden’s administration has pledged billions of dollars from an infrastructure law to fund the removal of all the nation’s lead pipes over the coming years -- but until that happens, people need solutions now.
- A clever trick -
Bushway's idea was to use the same chemical reaction used to restore contaminated soil: the exposure of dissolved lead to calcium phosphate powder produces a solid lead phosphate that stays inside the filter, along with harmless free calcium.
The filter has a clever trick up its sleeve: under the calcium phosphate, there's a reservoir of a chemical called potassium iodide.
When the calcium phosphate is used up, dissolved lead will react with potassium iodide, turning the water yellow - a sign it is time to replace the filter.
Student Wathon Maung spent months designing the housing on 3D printing software, going through many prototypes.
"What's great about it was that it's kind of this little puzzle that I had to figure out," he said.
Calcium phosphate was clumping inside the filter, slowing the reaction. But Maung found that by incorporating hexagonal bevels he could ensure the flow of water and prevent clumping.
The result is a flow rate of two gallons (nine liters) per minute, the normal rate at which water flows out a tap.
Next, the Barrie team would like to incorporate an instrument called a spectrophotometer that will detect the yellowing of the water even before it is visible to the human eye and then turn on a little LED warning light.
Paul Frail, a chemical engineer who was not involved in the work, said the group "deserves an incredible amount of credit" for its work, combining general chemistry concepts with 3D printing to design a novel product.
He added, however, that the filter would need further testing with ion chromatography instruments that are generally available in universities or research labs -- as well as market research to determine the demand.
Bushway is confident there is a niche. Reverse osmosis systems that fulfill the same role cost hundreds to thousands of dollars, while carbon block filters available for around $20 have to be replaced every few months, which is more often than her group's filter.
"I am over-the-Moon proud of these students," Bushway said, adding that the group hoped to work with partners to finalize the design and produce it at scale.
P.Anderson--BTB