Photocatalysis of low-concentration gaseous organic pollutants over electrospun iron-doped titanium dioxide nanofibers

Abstract

In this study, iron-doped titania (Fe–TiO2) nanoparticles were prepared and then coupled to a polymer material as a support to synthesize Fe–TiO2 nanofibers for photocatalytic degradation of gaseous pollutants (benzene, toluene, ethyl benzene, and o-xylene (BTEX)) at environmental sub-ppm levels. The characteristics of as-prepared photocatalysts were determined by SEM, XRD, and FTIR analyses. Spectral analysis of the as-prepared photocatalysts revealed that they were closely associated with the characteristics of Fe ions for Fe–TiO2 nanofibers. The photocatalytic degradation efficiencies (PDEs) of BTEX determined via Fe–TiO2 nanofibers varied with the ratios of Fe to Ti, suggesting the presence of an optimal Fe-to-Ti ratio. In addition, the PDEs of BTEX determined via two Fe–TiO2 nanofibers with low Fe-to-Ti ratios (0.001 and 0.004) were higher than those obtained from the undoped Fe–TiO2 nanofibers, whereas those of the other two Fe–TiO2 nanofibers with high Fe-to-Ti ratios (0.008 and 0.012) were lower. The average PDEs of BTEX decreased from 34 to 9%, 68 to 28%, 83 to 45%, and 90 to 55%, respectively, as the stream flow rates increased from 1 to 4 L min−1. These values also decreased with increasing initial concentration (IC). Specifically, at the lowest IC of 0.1 ppm, the average PDEs of BTEX were 33, 68, 83, and 91%, respectively, while they were 5, 8, 12, and 23%, respectively, at the highest IC of 2.0 ppm. Similarly, the PDEs of BTEX decreased significantly as the RH increased. Overall, the electrospun Fe–TiO2 nanofibers could be used to effectively decompose low-concentration gaseous organic pollutants when operational conditions were optimized.