Water and air pollution pose significant health risks to humans, with industrial wastewater containing heavy metals contributing to water pollution and indoor air pollution leading to respiratory concerns.

A research team led by Dr. XU Sichao from Institute of Solid State Physics, Hefei Institutes of Physical Science (HFIPS), Chinese Academy of Sciences (CAS) suggested a Titanium Dioxide Nanosieve Photocatalytic (Water/Air) Purifier in his study, which used nano-titanium oxide to purify air or water in a cost-effective manner.

"We used Ti mesh as the substrate," XU explained, "and rutile TiO₂ nanograss was grown on the mesh. The nanograss, which formed a thin coating, was composed of thin TiO₂ nanorods with abundantly exposed {110} facets. They served as effective reduction sites and facilitating transfer of the photoelectrons to the surface."

The TiO₂ nanograss on Ti mesh (TNTM) showed excellent photocatalytic removal of Cr(VI) ions from plating wastewater under sunlight. After photocatalytic reaction, the TNTM could be nondestructively regenerated by a facile electrolyzation method. The Cr ions on the TNTM could also be collected easily, avoiding a secondary pollution.

The easy fabrication, high removal capacity of Cr(VI) ions, and simple nondestructive regeneration as well as facile collation of Cr(III) ions made TNTM a very suitable photocatalytic architecture for practical application in Cr ions wastewater treatment.

They also conducted experiment in a local pharmaceutical factory for polluted air. The TiO₂ nanograss mesh also showed excellent decontaminating effect using the TNTM.

"We hope that our approach will contribute to making environments cleaner and healthier," said XU.

Electric-field-enhanced photocatalytic removal of Cr(VI) under sunlight of TiO₂ nanograss mesh with nondestructive regeneration and feasible collection for Cr(III). (Image by XU Sichao)