Cleaning with photons: Challenges and opportunities in photocatalytic water -and air purification

The discovery of photocatalytic water splitting and photocatalysis dates back to the 1970s. Since then, several semiconductor nanoparticles have been found to have remarkable photocatalytic activity to eliminate health-threatening bacteria, viruses, worms and persistent, bioaccumulative organic water pollutants as pharmaceuticals, pesticides and endocrine disruptors. Surprisingly, despite significant research efforts, studies have mainly remained in the stage of laboratory experiments and only a limited number of products using this technology can be found on the market. Materials and devices with sufficient efficiency, stability and low cost are yet to be demonstrated. Among the known semiconductor photocatalysts, titanium dioxide (TiO₂) is the most popular owing to its excellent chemical stability, low toxicity and low cost.

I will discuss the main technical barriers impeding the commercialization of this technology and show several strategies as potential countermeasures to improve the photocatalytic efficiency of titania based solar environmental purification systems. As an example, the first prototype of a low cost, durable and easy to operate solar-thermal water purification device will also be presented, which allows the production of bio-hazard-free drinking water from contaminated water resources.
We gratefully acknowledge the financial support of EPFL AIT Innovation Grant and the Zeno-Karl Schindler Foundation.
 

1. Szirmai P., Náfrádi B., Arakcheeva A., Szilágyi E., Gaál R., Nemes N. M., Berdat X., Spina M., Bernard L., Jaćimović J., Magrez A., Forró L., Horváth E.

1. Spina M., Bonvin E., Sienkiewicz A., Nafradi B., Forró L., Horváth E.

1. Hodos M., Horváth E., Haspel H., Kukovecz A., Kónya Z., Kiricsi I.