Light work of emerging micro-pollutants

Carbon-based organic microscopic pollutants in water can be removed by treatment with high-intensity pulses of light in a process developed and demonstrated by researchers at KAUST.

This photodegradation process was already known to be possible, but its use was limited by the long treatment time required for it. Luca Fortunato, Thomas Anthopoulos and their colleagues have demonstrated that this photodegradation treatment can be dramatically accelerated with high-intensity light pulses generated from xenon flash lamps.

“An interesting aspect of this work is that we combined the expertise and technologies of two different areas,” Fortunato says. He explains that a collaboration between two different research departments—KAST’s Solar Center and the Center for Water Desalination and Reuse—allowed the team to adopt a pulsed light system that was previously designed to process semiconductor materials for transistors and solar cells. was used for.

Organic microscopic pollutants (OMPs), known as emerging contaminants, include pharmaceuticals, hormones, compounds in personal care products, and a long list of industrial chemical additives. They are a growing problem in waterways because of weaknesses in environmental legislation. They are released in many places, are highly stable in water and can have toxic effects on human health even at very low concentrations. A few nanograms per liter can be harmful in some cases.

“They are continually being released into waterways by wastewater treatment plants, with conventional treatment methods proving only limited effectiveness in removing these contaminants,” Fortunato says.

The researchers found that the effectiveness of high-intensity pulsed light (HIPL) varied significantly depending on parameters including the number of pulses and the total energy dose delivered by the light. This allowed them to identify the most effective conditions for treating test solutions containing 11 critical OMPs, including drugs, hormones and industrial chemical contaminants.

They found that HIPL treatment triggers the upregulation of OMPs with exceptional degradation rates.

“Our innovative approach allows for the effective removal of OMPs from water within milliseconds, making it ideal for high-throughput water treatment applications,” says Anthopoulos.

The treatment has the potential to be a highly effective, straightforward and scalable solution to a growing environmental problem.

The team is still working to further improve the system’s efficiency and increase its throughput. Their next step is to scale up the treatment setup.

“We hope to build a pilot-scale reactor soon so that a more realistic assessment of the efficiency of the treatment on wastewater can be done,” Fortunato says.