Automobile Exhaust Removal Performance of Pervious Concrete with Nano TiO₂ under Photocatalysis

The urban environment is facing serious problems caused by automobile exhaust pollution, which has led to a great impact on human health and climate, and aroused widespread concern of the government and the public. Nano titanium dioxide (TiO₂), as a photocatalyst, can be activated by ultraviolet irradiation and then form a strong REDOX potential on the surface of the nano TiO₂ particles. The REDOX potential can degrade the automobile exhaust, such as nitrogen oxides (NO_x) and hydrocarbons (HC). In this paper, a photocatalytic environmentally friendly pervious concrete (PEFPC) was manufactured by spraying nano TiO₂ on the surface of it and the photocatalytic performance of PEFPC was researched. The nano TiO₂ particle size, TiO₂ dosage, TiO₂ spraying amount, and dispersant dosage were selected as factors to investigate the efficiency of photocatalytic degradation of automobile exhaust by PEFPC. Moreover, the environmental scanning electron microscope (ESEM) was used to evaluate the distribution of nano TiO₂ on the surface of the pervious concrete, the distribution area of nano TiO₂ was obtained through Image-Pro Plus, and the area ratio of nano TiO₂ to the surface of the pervious concrete was calculated. The results showed that the recommended nano TiO₂ particle size is 25 nm. The optimum TiO₂ dosage was 10% and the optimum dispersant dosage was 5.0%. The photocatalytic performance of PEFPC was best when the TiO₂ spraying amount was 333.3 g/m². The change in the photocatalytic ratio of HC and NO_x is consistent with the distribution area of nano TiO₂ on the surface of the pervious concrete. In addition, the photocatalytic performance of PEFPC under two light sources (ultraviolet light and sunlight) was compared. The results indicated that both light sources were able to stimulate the photocatalytic performance of PEFPC. The research provided a reference for the evaluation of automobile exhaust removal performance of PEFPC.