Coupling of Photocatalysis and Adsorption using a Single Multifunctional Filter for Gas-Phase Toluene Removal

Abstract

The removal of volatile organic compounds (VOCs) from air streams remains a key challenge in air purification processes. Conventional technologies such as photocatalysis and adsorption are effective but suffer from significant limitations when applied separately. In this study, five commercial activated carbon materials were first evaluated using adsorption isotherm measurements to identify the most suitable adsorbent. The selected activated carbon powder (AC) was then coated on an innovative textile-based filter composed of optical fibers and TiO₂. UVA LEDs were used to irradiate the optical fibers, allowing uniform and efficient illumination of the TiO₂ coating. Two coating configurations were investigated to study the effect of the distribution of activated carbon and TiO₂ on pollutant removal. This approach promotes the synergistic coupling of adsorption and photocatalysis within the same structure. The first configuration comprises a filter with two distinct functional sides. In contrast, the second configuration consists of a filter coated with a homogeneous mixture of TiO₂ and AC. In both cases, adsorption was first carried out until saturation, followed by photocatalytic treatment under UVA irradiation. Toluene was used as a representative model compound to evaluate the performance of the textile filter. The results showed that the filter configuration significantly affects toluene removal, with up to 70 % degradation achieved when adsorption and photocatalysis were separated on two sides. These findings confirm the potential of integrating both processes in compact air purification devices.