Researchers from King Abdullah University of Science and Technology (KAUST) have developed a procedure involving high-intensity pulses of light that can successfully remove carbon micro-pollutants from water.
The photodegradation process
This process was already suspected to be feasible, although it was limited due to the long treatment times that were required for the micro-pollutants to be successfully eradicated from water. Luca Fortunato, Thomas Anthopoulos and their team have demonstrated that this photodegradation process can be significantly accelerated utilising high intensity light pulses generated from a xenon flash lamp.
“An interesting aspect of this work is that we combined the expertise and technologies of two different fields,” explained Fortunato. This study involves the collaboration of two different research departments: KAUST’s Solar Centre, and KAUST’s Water Desalination and Reuse Centre. This allowed scientists to adopt a pulsed light system, previously unthought of in the removal of micro-pollutants, that was initially used to process semiconductor materials for transistors and solar cells.
Organic micro-pollutants are known as emerging contaminants, and include a long list of pharmaceuticals, hormones, and compounds in personal care products and industrial chemical additives. Due to weaknesses in environmental legislation, organic micro-pollutants are an increasing problem in waterways. This is concerning because they are released from many different locations, are highly persistent in water, and can have toxic impacts on human health in both small and high concentrations— as little as a few nanograms per litre can be harmful in some cases.
“They are being continually released into waterways by wastewater treatment plants, with conventional treatment methods proving to have only limited effects in removing these contaminants,” said Fortunato.
Researchers discovered that the effectiveness of high intensity pulsed light varied significantly depending on the parameters set. Fortunato adjusted factors including the number of pulses and the total energy dose delivered by the light.
This allowed scientists to identify the most effective conditions for successful treatment. Fortunato and his team tested the effectiveness of these conditions by effectively treating a test solution that contained eleven significant organic micro-pollutants that included drugs, hormones and industrial chemical contaminants.
The research team discovered that the high intensity pulses of light treatment triggered the decomposition of the organic micro-pollutants with an extraordinary rate of degradation. “Our innovative approach allows for efficient removal of OMPs from water within milliseconds, making it ideal for high-throughput water treatment applications,” commented Anthopoulos.
This recently developed treatment for organic micro-pollutants has the potential to become a highly effective, straightforward and scalable solution to an increasing environmental problem. The research team is now working to improve the system’s efficiency even further and increase its throughput. They are now working on their next step towards achieving this, which is scaling up the treatment setup.
“We hope to soon build a pilot-scale reactor to more realistically assess the efficiency of the treatment on wastewater effluent,” Fortunato concluded.