Victoria University research tackles nitrate pollution
Research carried out at Victoria University of Wellington has made big strides in tackling New Zealand’s serious nitrate pollution problem.
PhD student Putri Fraser, together with researchers from the University’s School of Chemical and Physical Sciences, have combined iron and natural silicates to create a safer, easier method of removing nitrate pollution from waterways. Nitrate pollution is a serious issue, deteriorating river habitats and decimating aquatic life.
“Previous research shows that nano-sized iron can remove pollutants from soil and waterways, but it’s not a perfect solution,” Putri says. “The iron is magnetic, so these nano-sized particles can clump up, reducing their reactivity and also making them difficult to work with. This clumping can also occur if they are ingested by fish, potentially harming wildlife.”
Putri needed to find a way of making the nano-sized iron less likely to clump but still maintain its reactivity towards pollutants. She tested several different products, but the solution came in the form of a microsilicate product she first encountered while working as a Summer Research Scholar at Callaghan Innovation in 2012.
“This microsilicate product is cheap to produce and is a by-product of thermal power generation,” Putri says. “My supervisor (Dr Robin Fulton from Victoria University’s School of Chemical and Physical Sciences) and I thought it was very fitting to use another waste product to deal with nitrate waste.”
Putri says they were able to coat the microsilicate with the nano-sized iron, effectively increasing the size of the nano-iron while maintaining its reactivity.
“Coating the silicate with the iron makes it easier to distribute the iron in a solution, so the soil gets better coverage,” Putri says. “Also, as the silicate-coated nanoparticles cannot clump, we don’t have to worry about any potential negative interactions with fish.
“Putri’s research is significant,” says Dr Fulton “as not only has she made new materials for removing nitrate from waterways, she has also discovered that the ability of the nano-sized iron to remove nitrates is strongly influenced by the minerals around it. This discovery has implications for determining the best strategies for using nano-sized iron to address many environmental pollution issues.”
The next step is to see if this method can help with other pollutants.
“Along with a research team at the School of Chemical and Physical Sciences, I’m going to try different metals and coatings to see if there is a more effective combination, and also to see it’s possible to remove other pollutants from the soil using this method,” Putri says.
Putri is graduating with a PhD in Chemistry at Victoria University’s May graduation next week.