Preparation of Visible Light Photocatalytic Asphalt Pavement using Fe Doped g-C3N4 for Removal of Vehicular NO: Feasibility Study

Abstract

Photocatalytic pavement based on traditional photocatalyst has been proposed to cure the air pollution caused by automobile exhaust. However, the low degradation efficiency under visible light limits the application of photocatalytic pavement in practice. A visible light photocatalytic asphalt pavement with higher degradation efficiency was developed in this study using Fe doped g-C3N4 (Fe-C3N4) as photocatalyst. The photocatalyst was added to slurry seal with the aim of improving wear resistance of the photocatalytic coating. The modification mechanism of Fe-C3N4 was analyzed by combining the microscopic characterization and NO removal efficiency of photocatalyst. The photocatalytic performance, skid resistance, and wear resistance of asphalt pavement were studied under visible light. The results indicated that Fe element could be used as an effective electron receptor to capture electrons in the conduction band of g-C3N4, which lead to a lower recombination rate of photoinduced electron-hole pairs, and could enhance the absorption intensity and broaden the response of g-C3N4 to visible light. In addition, the slurry seal specimen using epoxy resin instead of emulsified bitumen as binder had better photocatalytic performance. The NO removal efficiency of the epoxy resin slurry seal specimen reached the highest level when the Fe-C3N4 content was up to 50% of the quality of mineral powder. Both skid resistance and wear resistance of the specimen met the standard requirements of pavement. The specimen still retained an effective photocatalytic ability after the abrasion test.