Adsorption backup following light-emitting diode-irradiated photocatalytic unit for control of low-degraded toxic gaseous compounds

摘要

Although several visible light-emitting diode (LED)-irradiated photocatalysts exhibited low photocatalytic decomposition efficiencies for toxic gaseous pollutants, activated carbon fiber (ACF) has rarely been used as a backup adsorption device for photocatalytic systems. Accordingly, this study accessed the applicability of a supplemental ACF following a visible LED-irradiated S-TiO2 unit for the control of low-degraded benzene and toluene. The characteristics of the S-TiO2 and ACF were determined using an XRD, a UV-Vis-NIR, and an FTIR spectrophotometer. For an LED/S-TiO2 system, low degradation efficiencies regarding benzene and toluene (close to zero-7.2% and 7.1–64.4%, respectively) were found. In contrast, the mean degradation efficiencies of both compounds obtained from the photocatalytic-ACF hybrid system were all close to 100%. In addition, no peaks were observed in the gas chromatogram of air samples taken at the outlet of the hybrid system, whereas several trace peaks were observed in the standalone photocatalytic reactor results. The breakthrough of the ACF occurred at approximately 14 and 28 hours for benzene and toluene, respectively, and saturation occurred at approximately 28 and 42 hours, respectively. Consequently, this study newly found that the supplemental activated carbon fiber following a visible LED-irradiated S-TiO2 unit could be applied effectively for the control of low-degraded toxic benzene and toluene.