
The inexpensive faucet attachment fits all standard sinks and can quickly alert a person of toxic contaminants in tap water, and remove them. Credit: Rebecca Bushway/American Chemical Society
High school students from Maryland recently turned a classroom lesson from their teacher into a practical invention that can easily and inexpensively solve the problem of lead contamination in drinking water.
At the spring meeting of the American Chemical Society, chemistry teacher Rebecca Bushway debuted the inexpensive faucet attachment she and 10 of her students invented that can not only alert a person of toxic contaminants in water, but also quickly remove them.
Years after the disaster in Flint, Michigan, residents still do not have access to clean drinking water. When Bushway, a chemistry teacher at Barrie School, caught a news story on the topic, she pondered out loud to her class if it would be possible—based on the chemistry they already knew and what she was teaching that day—to design something that could help people in these situations.
“Many science teachers think we need to give kids massive amounts of content so they have the background to eventually do something interesting,” said Jon Kidder, head of the Barrie School. “[We] think the opposite is true. When you give them content, then simultaneously give them an interesting, relevant problem to solve, that’s when they roll up their sleeves to understand the chemistry. Their curiosity is sparked, and when that happens, their knowledge goes far deeper than a textbook.”
Bushway’s challenge quickly became a full-blown idea and passion for students while they were physically out of the classroom during the COVID-19 pandemic. While at home, the students met virtually and discussed designs for a filter that could remove toxic metals that can be easily screwed onto a sink’s faucet.
Bushway and the students settled on using calcium phosphate in the filter since it’s effective, inexpensive, and already present in humans.
“We already understood phosphates really well because [we studied] how they work amazingly for soil irradiation,” said Bushway.
Various lead filtration systems already exist, but their high cost and large size can be barriers. In addition, few of them provide any indication that they should be changed, and none indicate that the water could pose an immediate health risk—which is what makes the students’ filter special.
Bushway and her students coupled the design with a semi-permeable membrane that contains potassium iodine. When the potassium iodine reacts with lead, it turns a vibrant yellow, making it visible to the naked eye even at small concentrations.
During the ACS presentation, Bushway showed an animation demonstrating how the filter works. First, the contaminated water flows through the sink adapter and strikes the diverter plate. The diverter plate then slows the water down to ensure it flows over the panels into the side channels, where it has enough time to come into contact with and react to the calcium phosphate. Once the water has completed the reaction, it flows through the output pipe to the bottom of the filter, where the potassium iodide membrane is located.
Of course, the team ran into hiccups during the design process, including 14 failed prototypes just for the adapter. Eventually, though, they 3D-printed a universal attachment and a 3-inch-tall filter housing using an environmentally friendly biodegradable plastic.
Next, the students are working to add a tiny spectrophotometer with a single-wavelength LED to the bottom of the filter cartridge, where the water gets dispensed. Their plan is to have an indicator light that turns on as soon as the detector identifies the yellow color of the lead iodide—even before the color is detectable by the human eye.
But with the general design worked out and successfully tested, Bushway says they are ready to work with a partner to start manufacturing the filters—which they plan to sell for $1 or less.
“The goal isn’t just to do things now,” said Kidder. “When students have the chance to experience something at 16, when they are doing their postdoc at 27, and they’ve already done a whole series of smaller projects, we don’t know what they are going to invent. Becoming an entrepreneur scientist takes practice. In some ways, this project isn’t the culmination. It’s the spark.”