From L to R: Prof. Qilin Li, Yuren Feng, and Kuichang Zuo
A Rice University research team led by Qilin Li, the Karl F. Hasselmann Professor of Civil and Environmental Engineering at the George R. Brown School of Engineering and Computing, has been named a winner of the ACS ES&T Engineering Best Paper Awards by the American Chemical Society (ACS). The team was recognized for its paper, “Polarity Modulation Enhances Electrocatalytic Reduction of Nitrate by Iron Nanocatalysts.”
The award honors the most impactful research published in the journal over the past year, with recipients selected based on scientific rigor, originality, and relevance..
“We are delighted and honored to receive this recognition from ACS for our paper about a new chemical-free method to reduce nitrate contamination in water,” said Li, who also serves as co-director of Rice’s Nanotechnology Enabled Water Treatment (NEWT) Center.
Nitrate is a naturally occurring compound that is essential in small amounts. However, elevated levels stemming from fertilizers, animal waste, or leakage from sewage and industrial processes, pose severe health risks and long-term ecological concerns.
Water contaminated with nitrates is usually purified through electrocatalytic reduction that converts nitrates into harmless nitrogen gas or valuable ammonia. However, the process is limited because negatively charged nitrate ions repel the negatively charged catalyst surface, slowing conversion rates.
In their award-winning paper, Li and her team presented a simple and elegant solution: applying intermittent, short (30-second) pulses of positive current to attract and bind nitrate ions to the catalyst. This brief positive pulse, followed by a long negative current, increased nitrate conversion by 25% compared to traditional methods of using constant negative potential.
“Our paper demonstrated polarity modulation as an efficient strategy to catalyze the breakdown of nitrate and reduce contamination in water sources,” Li added. “It is cost-effective, sustainable, and requires a simple operational change that can be readily implemented in large-scale purification systems. We are also excited by its potential to remove other negatively charged pollutants, such as chromate and selenate, from water.”