Scientists develop low-cost sensor to safeguard water from fireworks pollution

A team of researchers from Nanjing University and Nanjing Normal University has designed a new, affordable sensor to detect toxic perchlorate in water, paving the way for better environmental monitoring and healthier communities. The sensor, inspired by porphyrin molecules and costing less than two US dollars, offers rapid and highly accurate detection of perchlorate, a harmful pollutant that often escapes into rivers and drinking water through fireworks manufacturing and industrial operations.

Perchlorate is a persistent pollutant known for its mobility, water solubility, and stability. While perchlorate can occur naturally, its largest sources are industrial activities including the production of fireworks, explosives, and some military devices. In China’s Xiangjiang River Basin, for instance, heavy fireworks production in recent years has led to dramatic increases in perchlorate concentrations, sometimes surpassing 1,000 milligrams per liter in wastewater. The pollutant is hazardous to human health, especially because it disrupts thyroid gland function and hormone production.

Current methods for perchlorate detection such as ion chromatography and mass spectrometry are often expensive and require complex sample preparation in laboratory conditions. There is greater need for portable, simple tools for real-time screening of polluted water, which would facilitate quick responses to contamination events and help industries comply with new regulations. The World Health Organization and China’s latest national standards have set strict limits for perchlorate in drinking water, prompting a demand for robust field monitoring.

To answer this need, the research team developed a liquid-contact ion-selective electrode (ISE) using a polyvinyl chloride (PVC) membrane enhanced with a custom-made porphyrin-based ionophore. The heart of the membrane incorporates a derivative called iron(III) meso-tetraphenylporphine chloride, or FeIIITPPCl, carefully chosen for its superior ability to recognize and bind perchlorate ions while ignoring common interfering substances. The sensor’s chemical recipe was refined through systematic screening and optimization, leading to excellent selectivity, a wide detection range, and extremely low detection limits.

“ISEs are known for their simplicity and field deployability, yet their selectivity often lags behind complex lab instruments,” explained Dr. Wentao Li, principal investigator. “By using this specially designed porphyrin-based carrier, our sensor can spot perchlorate ions at very low levels and resist being misled by similar anions such as sulfate or nitrate.”

The sensor reacts rapidly, delivering results in as little as five seconds, and can tolerate a broad variety of environmental conditions, including a wide range of pH (from acidic to mildly alkaline). When tested in actual fireworks production wastewater and in natural surface waters, the device proved capable of detecting perchlorate with impressive recovery rates—often matching the measurement accuracy of much more expensive instruments. Even without sample pretreatment, the recovery for spiked surface water averaged over 104 percent, while measurements in real fireworks wastewaters averaged over 96 percent recovery.

Beyond scientific innovation, the sensor’s low cost and ease of use make it ideal for broad deployment in at-risk communities and by industry professionals responsible for wastewater monitoring. The team estimates the cost per unit is under two dollars, offering a pathway to routine, on-site testing with disposable sensors.

Looking ahead, the researchers plan to adapt their design to address long-term stability and consider transforming the sensor from a liquid-contact to a solid-contact format, further improving its durability against environmental variations like temperature changes.

According to the authors, this new technology represents a significant advance in the global effort to tackle perchlorate pollution. By combining precision molecular design with practical field applications, the team’s work brings safer water and improved public health one step closer for populations exposed to the risks from industrial and fireworks-related contamination.

The full study is open access and can be found in Energy & Environment Nexus, Volume 1, 2025.

=== 

Journal reference: Li B, Li B, Han Y, Li Q, Liang C, et al. 2025. Rational design of porphyrin-based ionophores for enhanced perchlorate selectivity in ion selective electrodes: application to fireworks wastewater analysis. Energy & Environment Nexus 1: e009  

https://www.maxapress.com/article/doi/10.48130/een-0025-0007  

=== 

About Energy & Environment Nexus:
Energy & Environment Nexus is an open-access journal publishing high-quality research on the interplay between energy systems and environmental sustainability, including renewable energy, carbon mitigation, and green technologies.

Follow us on Facebook, X, and Bluesky.