An inexpensive water filter has been engineered by high school students in Maryland to tackle the pervasive problem of lead-contaminated drinking water. The 3D-printed faucet attachment contains a mixture of calcium phosphate and potassium iodide powder to bind with waterborne lead.

The device also turns the water yellow as a visible indicator of the presence of lead. According to Rebecca Bushway, the teacher at the helm of the project, “A few years ago, I saw a video of a woman in Michigan turn on her tap water, and it came out brown. That made me think — because there’s really no safe level of lead in drinking water, wouldn’t it be nice to have a water filter that could tell you that your water is contaminated, well before it turns brown because of lead?”

As water flows through the 3 inch filter, lead binds with the calcium phosphate, resulting in the formation of lead phosphate and free calcium. A nylon screen at the bottom of the filter traps the lead phosphate,The filter attaches to a faucet and removes lead from tap water. Source: Rebecca Bushway which is an inert solid. When the calcium phosphate content is depleted, dissolved lead in the water reacts with the potassium iodide, causing the water to turn yellow as a visible indicator of potable water quality.

The student designers plan to incorporate a miniature spectrophotometer and an LED at the bottom of future filter iterations. As the spectrophotometer detects the yellow color, even when lead levels are so low that the color is not readily perceived by the human eye, the LED will be triggered to illuminate. The young engineers hope to sell the filters composed of a biodegradable plastic for as little as $1 each.

The water filter design and student research were presented at the American Chemical Society Spring 2022 meeting held virtually and in-person during March 20 to March 24.