Algal blooms occur naturally. However, the occurrence of blue-green algae (cyanobacteria) blooms and the possibility of production of algal toxins (cyanotoxins) have caused problems in water treatment processes for decades. The increase of harmful algal blooms in estuaries and freshwater aquatic systems poses threats to wildlife, livestock and humans. O’Shea’s research is funded by the National Science Foundation and the U.S. Department of Agriculture.
“Conventional water treatment techniques can be costly and can produce toxic by-products and pollutants,” O’Shea said. “We are working on a solar powered water decontamination technique that will be more cost-effective and can have broader applications.”
The process by which O’Shea and his research partners hope to destroy water toxins is called photocatalysis. It involves using natural sunlight and titanium dioxide — a naturally occurring oxide of the element titanium with a number of industrial applications including self-cleaning materials. It is a non-toxic pigment that, when excited by ultraviolet light, can destroy pollutants in water. The researchers have already effectively destroyed the cyanotoxins using the five percent of the spectrum that is UV light, according to O’Shea. Their next step is to increase the solar efficiency so they can utilize the rest of the spectrum in the process.
“One in every five children and more than 1 billion people do not have access to clean water. By the year 2025, about two-thirds of the world’s population will be faced with severe clean water shortages,” O’Shea said. “We can do something about it.”
By Ayleen Barbel Fattal