Solar Reactor for Photocatalytic Water Purification

Photocatalytic water purification utilizes light to degrade the organic contaminants in water and bears great hope to alleviate the deteriorating water pollutation problem. This work aims to develop a new solar reactor that features a new reactor design, a low-cost fabrication method of large-area TiO₂ thin films deposited on PMMA substrate and the potential for industrial applications. And the reactor would be used to decompose real sewage water.

The reactor fabrication starts with the development of large-area TiO₂ thin film on a lightweight, non-brittle PMMA substrate, which is the enabling factor for the large solar reactor. In the process, a thin layer of P25 TiO₂ nanoparticle is sprayed onto a PMMA substrate (footprint 1 m x 0.6 m) after mixing the P25 TiO₂ powders with DI water, then the PMMA substrate is soaked into chloroform to stick TiO₂ nanoparticles. After that, other structures for the solar reactor such as the fluidic channels, the reaction chamber and the inlet/outlet are machined by laser cutting on the PMMA plates and are then integrated to form the solar reactor. Finally, the solar reactor is tested in sunlight to decompose the model chemical methylene blue solution to characterize the performances. Currently, it measures a decomposition rate of 30% in 2 hours with a thoughput of 1.9 L/h. More studies are needed to further improve the efficiency and the thoughput.

In summary, this work has developed a solar reactor for photocatalytic water purification. Although the performance is still far from ideal, it is the first step to the development of a low-cost solar reactor and has the great potential for industrial applications.