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What's in the Water? Using nanoparticles for safe H2O

Written by: Randal Marks

During my undergraduate chemistry lab, we had local third graders bring in water from their tap for testing with us. The student who partnered with me brought in a bottle of hazy yellow filth. This was his tap water, coming from a well. When we opened the bottle, a sickening odor wafted out. The yellow color and stench suggested his water was full of sulfur. We went through the lab procedure, testing pH, dissolved oxygen and other water quality parameters, by opening the bottle for the shortest possible period to avoid the smell. The results were poor, to say the least. I could not believe this was the water the child had to use every day.

Experiences like this inspired me to join the Lab for Advanced and Sustainable Water Treatment, led by Dr. Kyle Doudrick, where I am a Ph.D. student. Our lab studies nanoparticles as catalysts for the treatment of drinking water. We synthesize new nanoparticles to use for sustainable treatment processes, evaluate nanoparticle-based treatment systems, and study the transport of nanoparticles that reach the environment.
Personally, I am working on focuses on photocatalysis, which occurs when a nanoparticle can absorb light energy. The absorbed light excites electrons in the nanoparticle, reacting with contaminants in drinking water and transforming them into non-toxic byproducts. The spectral range of light that a photocatalyst can absorb is a key aspect of photocatalysis, and my current study investigates a photocatalyst, BiVO4, that can absorb visible light. If an effective photocatalyst that absorbs visible light can be developed, solar light may be used as a power source for water treatment.

My dissertation project is on the development of earth-abundant catalysts for treatment of nitrite in drinking water. Current catalysts for nitrite treatment are based on platinum and palladium, which are cost-prohibitive for widespread adoption. By nano-structuring cheaper metals such as molybdenum, iron, and cobalt, more economical catalysts with comparable activity can be developed.

Our lab consists of other researchers using nanoparticles as a way to provide clean water. Graduate student Andrew Schranck focuses on waste-to-value conversion by using nanoparticles to generate electricity from urine. Urea, the most prevalent organic component of urine, can be transformed into CO2 by nickel-cobalt nanoparticles supported on an electrode. During this transformation, electrons are freed and electrical current is generated. This current may be captured as an energy source.

Junyeol Kim, a third-year Ph.D. student in our lab, studies the fate and transport of nanoparticles that enter the environment. This summer, he worked at the Notre Dame Linked Experimental Ecosystem Facility (ND LEEF). The facility, part of the Environmental Change Initiative, has multiple man-made streams that can be manipulated for controllable studies in real-world conditions. Junyeol released nanoparticles into streams with different streambeds—made of sand, pea gravel, cobble, or a mixture—in order to determine how the nanoparticles moved in the streams.

Junyeol’s study is especially timely, as nanoparticles are present in an increasing number of consumer products and are unavoidably released into the environment. Because nanoparticles behave differently than larger particles but are not dissolved in water, we must develop an understanding of how they move in the environment.

Undergraduates also play a pivotal role in contributing to our lab. Alumnus Alicia Czarnecki and current sophomore Emily Black have performed many photocatalyst experiments, and senior David Clark has been working with Andrew for the past two years. Recently, chemical engineering student Joe Seaman joined the lab, helping with the synthesis of nanoparticles. I am appreciative of the dedication these students and several others have shown to our research.

At the Lab for Advanced and Sustainable Water Treatment, we are using nanotechnology for innovative water treatment technologies. Using nanotechnology, we can create sustainable systems for treatment for both waste and drinking water that requires little-to-no energy while producing little-to-no waste. The research could bring life-changing solutions to those who, like the third-grade student, are living with unsafe drinking water.

Filed under: Ph.D. Defense, Student, Research