Performance of an innovative VUV-PCO purifier with nanoporous TiO 2 film for simultaneous elimination of VOCs and by-product ozone in indoor air

An innovative vacuum ultraviolet photocatalytic oxidation (VUV-PCO) air purifier, consisting of a photocatalytic unit bearing nanoporous TiO2 film, an ozone removal unit bearing Mn-Fe catalyst and a radial fan, was designed and constructed. The performance of the VUV-PCO air purifier in simultaneous elimination of VOCs and O3 by-product was, for the first time, evaluated in a sealed actual room. The evaluation was conducted in both intermittent on/off and continuous operations. The results illustrated that the air purifier had high efficiency in removing formaldehyde and moderate efficiency in removing benzene, toluene, ofm-xylene, ortho-xylene, pentanal, octanal and nonanal, which were released from particleboard into the sealed room. During the removal of formaldehyde decomposition and TVOC in intermittent three-time on/off operation, the air purifier exhibited good stability. During the operation without heating, the air purifier had high formaldehyde and TVOC removal efficiencies, reaching values of about 48.00% and 78.71%, respectively after 90 min. During the continuous operation, the air purifier was able to continuously and effectively remove formaldehyde, benzene homologues, aldehyde and ketone compounds, while the ozone removal unit was able to effectively eliminate ozone generated during VUV photocatalysis. The removal of TVOC by 38.25% was reached after 240 min. In addition, heating the ozone removal unit was found to not only accelerate the release of VOCs from particleboard, but also promote the decomposition of ozone. The ozone removal unit operated with heating was able to reduce ozone content from 250 to 75 ppb.