Nano-TiO 2 -Enhanced Surface Functionalization of Recycled Concrete Aggregates for Improved Degradation Efficiency of Low-Concentration Sulfur Dioxide.

This study investigates the enhancement of recycled concrete aggregate (RCA) surfaces with nano-TiO₂ for an improved degradation of low-concentration sulfur dioxide (SO₂). Nano-TiO₂ particles, known for their photocatalytic properties, were uniformly deposited on RCA surfaces. Upon exposure to SO₂ under light irradiation, the functionalized RCA exhibited significantly improved degradation efficiency. This was attributed to the photo-induced oxidation of SO₂ by nano-TiO₂. Enhanced degradation was further observed under UV light due to increased photoactivation. The nano-TiO₂ coating also showed good durability and stability, ensuring long-term effectiveness. The experimental outcomes reveal that TiO₂-treated recycled aggregates exhibit an 85% retained photocatalytic activity post five cycles of reuse. Furthermore, the investigation employs a second-order polynomial-based mathematical fitting function to generate a three-dimensional trend surface, visually illustrating the inverse relationships between sulfur dioxide degradation and environmental variables, such as initial concentration and flow rates. Finally, this study demonstrates the potential of nano-TiO₂-modified RCA for mitigating the environmental impact of low-concentration SO₂, contributing to the development of more sustainable construction materials and broadening RCA's applications in environmental remediation. [ABSTRACT FROM AUTHOR]