Synergetic effect between adsorption and photodegradation on nanostructured TiO/activated carbon fiber felt porous composites for toluene removal.

The low quantum efficiency and limited adsorption efficiency of TiO makes it only fit for the removal of VOCs with low concentrations. Herein, we for the first time fabricated nanostructured TiO/activated carbon fiber felt (TiO/ACFF) porous composites by the in situ deposition of TiO microspheres on the carbon fibers in ACFF. Interestingly, the TiO microspheres exhibit hierarchical nanostructures constructed by nanocrystals as building blocks. The TiO/ACFF porous composites possess excellent adsorption and photodegradation properties for toluene because of the synergetic effects between the nanostructured TiO and ACFF. The adsorption efficiencies of the TiO/ACFF porous composites reach approximately 98% at the toluene concentration (<1150ppm) and approximately 77% even at the high concentration of 6900ppm. Moreover, the ACFF in the TiO/ACFF porous composites significantly enhances photocatalytic property for toluene by hindering the recombination of electron-hole pairs, reducing the TiO band gap energy (E) to 2.95eV and accelerating toluene adsorption. At the toluene concentrations of 230ppm and 460ppm, the photocatalytic oxidation efficiency of toluene into CO arrives at 100% and 81.5%, respectively. Therefore, the TiO/ACFF porous composites with synergetic adsorption and photocatalytic activities have great potentials for toluene removal.