Photocatalytic concrete for degrading organic dyes in water

Abstract

Since the advent of photocatalytic degradation technology, it has brought new vitality to the environmental governance and the response to the energy crisis. Photocatalysts harvest optical energy to drive chemical reactions, which means people can use solar energy to complete some resource-consuming activities by photocatalysts, such as environmental governance. In recent years, researchers have tried to combine photocatalyst TiO₂ with building materials to purify urban air and obtained good results. One of the important functions of photocatalysts is to degrade organic pollutants in water through light energy, but this technology has not been reported in the practical application areas. To extend this technology to practical application areas, photocatalytic concrete for degrading pollutants in waters was proposed and demonstrated for the first time in this paper. The photocatalytic concrete proposed based on the K-g-C₃N₄ shows a strong ability to degrade the organic dyes. According to the experiment results, the angle of light source plays an important role in the process of photocatalytic degradation, while waters with pH value of 6.5-8.5 hardly influenced the degradation of organic dyes. When the angle of light source is advantageous for photocatalytic concrete to absorb more visible light, more organic dyes will be degraded by photocatalytic concrete. The degradation rate of methylene blue could reach about 80% in ½ hour under desirable conditions and is satisfied compared with that of reported works. This study implicates that photocatalytic concrete can effectively degrade organic dyes in water. The influences of changes in the water environment hardly affect the degradation of organic pollutants, which means photocatalytic concrete can be widely used in green infrastructures to achieve urban sewage treatment.

Keywords: Degradation; G-C3N4; Photocatalyst; Photocatalytic concrete; Pollutants; Solar energy.