Researchers at the Institute of Engineering Design (IPE) of the Chinese Academy of Sciences have created reusable nanoparticle catalysts. The development will help to effectively break down contaminants inside water filters without damaging them.

Such filters are maintained in perfect condition with strong acids, alkalis or oxidizers. However, chlorine-containing oxidants damage polyamide membranes and produce toxic by-products. A milder alternative is hydrogen peroxide, but it is slow to break down contaminants.

The scientists tried to trigger the Fenton reaction, that is, combine hydrogen peroxide with iron oxide, and form hydroxyl radicals that increase the efficiency of the process. It turned out that the proposed method would require additional costs. One way to reduce costs is to use the enzyme glucose oxidase, which simultaneously produces hydrogen peroxide and gluconic acid from glucose and oxygen. IPE professor Jianquan Luo and his colleagues decided to combine glucose oxidase and iron oxide nanoparticles into a system that accelerates the breakdown of pollutants based on the Fenton reaction, while creating a delicate cleaning system with high efficiency.

The nanoparticles were very effective at cleaning the membranes, restoring 94% of their original water filtering capacity. Because the nanoparticles don’t require exposure to harsh chemicals and are easy to extract, the researchers believe their new system is a “greener” and more cost-effective approach to cleaning nanofiltration membranes.