Photocatalytic purification of contaminated air in intensive care units by ZnSn(OH)6 nanoparticles.

The air purification in intensive care units (ICU) involving the removal of smog and volatile organic compounds (VOCs), disinfection, and sterilization are closely linked to important health issues. The environmental photocatalysis technology that could decompose gaseous pollutants into small molecular inorganic substances provides the potential solution. In a chamber of 30-m3 simulated ICU, photocatalytic purifier with ZnSn(OH)6 nanoparticles photocatalyst is set up to treat 10 VOCs with concentration below 2 ppm. Compared with regular purifiers of plasma and activated carbon, the present photocatalytic purifier can completely eliminate 10 varieties of low-concentration irritating VOCs without CO production. The continuous tests show that loading of 600 g ZnSn(OH)6 has capacity to treat large volumes of VOCs and remains high removal efficiencies up to 600-h operation. The results suggest that the photocatalytic purifier could be potentially applied for the treatment of contaminated indoor air particularly ICU. The mechanism of ZnSn(OH)6 photocatalysis is proposed to interpret the high performance and mineralization of the degradation process.