Purification of aromatic hydrocarbons via fibrous activated carbon/photocatalytic composite coupled with UV light-emitting diodes

Abstract

In the present study, the applicability of light-emitting diodes (LEDs) to a fibrous activated carbon (FAC)/titania (TiO₂) composite used for the purification of gas-phase benzene, toluene, ethyl benzene and xylene was evaluated. The surface and morphological properties of the FAC and prepared FAC/TiO₂ composite were investigated by X-ray diffraction and scanning electron microscopy. The study protocol included two different tests, comparison of FAC and the FAC/TiO₂ composite for BTEX removal efficiency and evaluation of the FAC/TiO₂ composite for benzene and toluene removal efficiency under differing operation conditions. The time-series ratios obtained with the FAC/TiO₂ composite showed longer removal times for all target compounds when compared to those of FAC alone. For both benzene and toluene, the breakthrough time decreased with the stream flow rate, whereas it increased with increasing light intensity under the experimental conditions employed in this study. The breakthrough time of benzene and toluene increased as increasing amounts of TiO₂ were coated onto the surface of FAC between 11 and 229 mg-TiO₂ (g-FAC)⁻¹, but decreased as the amount of TiO₂ increased to 451 mg (g-FAC)⁻¹. These findings indicate that the optimal TiO₂ weight for the removal process of benzene and toluene via the FAC/TiO₂ composite is between 229 and 451 mg-TiO₂ (g-FAC)⁻¹.

Keywords:

• light-emitting diodes
• fibrous activated carbon/TiO₂ composite
• breakthrough
• removal efficiency

Acknowledgements

This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korean Government (MEST) (2011-0027916). I would like to thank three graduate students (In-Woo Choi, Kun-Hwan Kim and Hyun-Jung Lim) in the Department of Environmental Engineering, Kyungpook National University, for their experimental setup, sample collecting and/or analyses.