Methylene blue (MB) was degraded by TiO2 and ZnO deposited on an activated carbon fiber (ACF) surface under UV light. The ACF/TiO2 and ACF/ZnO composites were characterized by BET, SEM, XRD, and EDX. The BET surface area was related to the adsorption capacity for composites. The SEM results showed that titanium dioxide and zinc oxide are distributed on the ACF surface. The XRD results showed that the ACF/TiO2 and ACF/ZnO composites contained a unique anatase structure for TiO2 and a typical hexagonal phase for ZnO respectively. These EDX spectra showed the presence of peaks of Ti element on ACF/TiO2 composite and peaks of Zn element on the ACF/ZnO composite. The blank experiments for either illuminating the MB solution or the suspension containing ACF/TiO2 or ACF/ZnO in the dark showed that both illumination and the catalyst were necessary for the mineralization of organic dye. Additionally, the ACF/TiO2 composites proved to be efficient photocatalysts due to degradation of MB at higher reaction rates. The addition of an oxidant ([NH4]2S2O8) led to an increase of the degradation rate of MB for ACF/TiO2 and ACF/ZnO composites.

The photocatalysts of Fe-ACF/TiO2 compositeswere prepared by the sol-gel method and characterizedby BET, XRD, SEM, and EDX. It showed that the BET surface area was related to adsorption capacity foreach composite. The SEM results showed that ferric compound and titanium dioxide were distributed on thesurfaces of ACF. The XRD results showed that Fe-ACF/TiO2 composite only contained an anatase structurewith a Fe mediated compound. EDX results showed the presence of C, O, and Ti with Fe peaks in Fe-ACF/TiO2 composites. From the photocataytic degradation effect, TiO2 on activated carbon fiber surface modifiedwith Fe (Fe-ACF/TiO2) could work in the photo-Fenton process. It was revealed that the photo-Fenton reactiongives considerable photocatalytic ability for the decomposition of methylene blue (MB) compared to non-treatedACF/TiO2, and the photo-Fenton reaction was improved by the addition of H2O2. It was proved that thedecomposition of MB under UV (365nm) irradiation in the presence of H2O2 predominantly accelerated theoxidation of Fe2+ to Fe3+ and produced a high concentration of OH. radicals.

In this paper, non-treated ACF (Activated Carbon Fiber) /TiO2 and Zn-treated ACF/TiO2 were prepared. The prepared composites were characterized in terms of their structural crystallinity, elemental identification and photocatalytic activity. XRD patterns of the composites showed that the non-treated ACF/TiO2 composite contained only typical single and clear anatase forms while the Zn-treated ACF/TiO2 contained a mixed anatase and rutile phase with a unique ZnO peak. SEM results show that the titanium complex particles are uniformly distributed on and around the fiber and that the titanium complex particles are more regularly distributed on and around the ACF surfaces upon an increase of the ZnCl2 concentration. These EDX spectra show the presence of peaks from the C, O and Ti elements. Moreover, peaks of the Zn element were observed in the Zn-treated ACF/TiO2 composites. The prominent photocatalytic activity of the Zn-treated ACF/TiO2 can be attributed to the three different effects of photo-degradation: doping, absorptivity by an electron transfer, and adsorptivity of porous ACFs between the Zn-TiO2 and Zn-ACF.