Experimental study on photocatalytic degradation efficiency of mixed crystal nano-TiO2 concrete

The photocatalytic mixed crystal nano-TiO2 particles were incorporated with concrete by means of the internal doping method (IDM) and spraying method (SPM) in this paper. To evaluate the photocatalytic degradation efficiency of mixed crystal nano-TiO2 concrete, the methyl orange (MO) was chosen to simulate pollutants. The physicochemical characteristics and photocatalytic performance of mixed crystal nano-TiO2 concrete prepared by above two different methods were experimentally investigated under UV irradiation and solar irradiation. Furthermore, the effects of two key influential factors including pollutant concentration and irradiation condition were also analyzed and discussed. Experimental results indicate that the nano-TiO2 concrete prepared by the spraying method (SPM) exhibits maximum photocatalytic degradation efficiency of 73.82% when the sprayed nano-TiO2 slurry concentration is 10mg/L. The photocatalytic degradation efficiency of unpolished nano-TiO2 concrete is much higher than that of polished nano-TiO2 concrete under the same exposure time of UV irradiation. Moreover, the photocatalytic degradation efficiency of nano-TiO2 concrete decreases with the increase of pollutant concentration. The irradiation condition has an obvious influence on the photocatalytic degradation efficiency of nano-TiO2 concrete. In the aspect of applications, the practical recommendations for the nano-TiO2 concrete with self-cleaning capacity were presented according to the experimental results.