Filtration fibres for cleaning water

Composite fibres made of porous polystyrene combined with antimicrobial silver-doped zinc oxide nanoparticles could help improve membranes for water purification applications, such as removing oily contaminants from wastewater. 

The fibres were developed as a collaboration between Qatar University, the University of Houston in the US and the ConocoPhillips Global Water Sustainability Center in Qatar.

The fibres’ porous structure allows them to attract and retain oily contaminants, while the silver and zinc oxide components effectively prevent microbial build-up, or biofouling, which is a major issue in water treatment applications. The nanoparticles are evenly distributed over the fibres, which are made in a one-step ‘electrospinning’ process using a fine stream of liquid that is drawn out by an electric field. Including silver as a dopant within zinc oxide nanoparticles prevents them from agglomerating, which can occur if silver and zinc oxide are simply mixed.

The team has more recently found that zinc oxide also encourages the decomposition of organic contaminants in the presence of sunlight. They plan to publish details of this additional activity in the future.

“We are now optimizing some aspects [of the fibres],” says Qatar University materials scientist Mohammad Hassan. This ongoing work aims to make more structurally robust membranes from the fibres that can cope with high water flow rates, and to scale up production to the levels needed for commercialization.

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