Removal effect on stormwater runoff pollution of porous concrete treated with nanometer titanium dioxide

Abstract

Development of the cities is facing many problems; one of them is runoff water pollution. On the other hand, some technologies have been applied to remove water pollution such as the photocatalytic effect method using nano-titanium dioxide (nTiO2). That technology exhibited a significant effect to remove various pollutants from runoff water. The use of nTiO2 on porous concrete (TPC) considers a new technology, which is effective and clean technology to deal with the non-point source pollution. In this paper, the permeability, mechanical properties and water purification capacity of using that technology have been investigated to analyze the environmental effect of TPC. In addition, this study tested the environmental impact using zebrafish aquatic toxicity and alkali dissolution experimentally. Moreover, the photocatalytic oxidation reaction of TPC is exploited to detect the purification effects of three typical pollutants, i.e., methylene blue, total phosphorus, and ammonia nitrogen. At the same time, three different application methods with three different concentrations of nTiO2 have been utilized in the porous concrete to obtain the optimum value. The removal effectiveness in pollutants is also measured, moreover the purification durability effectiveness is tested. After culturing the zebrafish embryos in the leachate of porous concrete with nTiO2, the hatching rate was 91.7%, which proved that this technology has little aquatic toxicity to organism and environment. The capacity of pollutants removing was effective and reached up to 60%-90%. Besides, porous concrete treated by nTiO2 that was placed in actual weather for a month showed a half reduction in water purification effect.