Glasgow Chemists Harness Dual-Frequency Ultrasound to Mineralize BPA in Water

Glasgow Chemists Harness Dual-Frequency Ultrasound to Mineralize BPA in Water

(IN BRIEF) Researchers at the University of Glasgow’s School of Chemistry have developed a novel, catalyst-free ultrasound method to destroy bisphenol A (BPA) in water. By applying two ultrasound frequencies simultaneously, their prototype generates cavitation bubbles that reach extreme temperature and pressure, breaking BPA down into harmless carbon dioxide. In laboratory tests, the 20 kHz/37 kHz combination removed 94% of BPA and reduced chemical oxygen demand by 67% within 40 minutes. Unlike traditional treatment that transfers BPA into sludge or activated carbon, this sonochemical approach fully mineralizes the pollutant, eliminating secondary waste. Published in Ultrasonics Sonochemistry, the work opens the door to treating other persistent pollutants and “forever chemicals.” The team, led by Shaun Fletcher, Dr. Lukman Yusuf, and Professor Mark Symes, is exploring industrial partnerships and scaling up the system for water treatment facilities.

(PRESS RELEASE) GLASGOW, 6-Aug-2025 — /EuropaWire/ — Chemists at the University of Glasgow have unveiled an innovative, chemical-free technique for eliminating bisphenol A (BPA)—a pervasive water contaminant—by harnessing precisely controlled ultrasound waves. Their laboratory‐scale system can eradicate up to 94% of BPA from tainted water samples by generating microscopic cavitation bubbles that mimic the extreme conditions found on the sun’s surface.

This sonochemical process relies on dual‐frequency ultrasound to produce millions of tiny, high‐energy bubbles. As these bubbles expand and violently implode, they generate fleeting “hot spots” of intense temperature and pressure, which cleave BPA molecules into benign byproducts like carbon dioxide. In trials combining 20 kHz with 37 kHz ultrasound over 40 minutes, the researchers achieved the greatest efficacy—degrading 94% of BPA and cutting overall chemical oxygen demand by 67%.

Unlike conventional treatment methods—such as activated sludge or carbon adsorption, which merely remove BPA from water and concentrate it in secondary waste—this approach directly decomposes the pollutant, obviating the need for further disposal of hazardous residues. The team’s findings, published in Ultrasonics Sonochemistry, mark the first demonstration that dual‐frequency ultrasound alone can effectively mineralize BPA without additional catalysts or chemicals.

Lead researcher Shaun Fletcher noted that existing sewage treatment plants are not optimized for BPA removal and often transfer the chemical into sludges that still require disposal. “Our dual‐frequency ultrasound system degrades BPA in situ, leaving no contaminated sludge behind,” he explained. Dr. Lukman Yusuf added that their bubble‐generation technique builds on earlier work targeting other organic pollutants, such as methylene blue, and could be extended to tackle “forever chemicals” like PFAS. The researchers are engaging with water utilities to explore scaling up the technology for industrial use.

This breakthrough follows the Symes Group’s recent achievement in using ultrasound to synthesize nitrate from air and water—an advance that promises sustainable on-farm fertilizer production. Professor Mark Symes, the group’s head and corresponding author of the BPA paper, emphasized ultrasound’s growing accessibility and versatility: “While traditional sewage systems excel at handling routine waste, emerging toxins demand specialized solutions. Sonochemistry can create conditions ‘out of this world’ inside minuscule bubbles, yet the process is safe and easily monitored.”

With support from EPSRC, the Royal Society, and the University of Glasgow, the team is now focused on scaling their prototype to process larger water volumes and investigating ultrasound’s capacity to degrade a broader spectrum of contaminants.

SOURCE: University of Glasgow