Synergistic effect of UV pretreated Fe-ZSM-5 catalysts for heterogeneous catalytic complete oxidation of VOC: A technology development for sustainable use

Highlights: • UV pretreatment of the catalyst activate the surface for oxidation of pollutants. • Complete mineralization of VOC occurred followed by adsorption. • ·we want to represent (.OH) as hydroxyl radical showing with free radical means one dot on the OH group OH and −OH we want to present this OH group as Hydroxyl ion with negative charge (OH(-)) are main radicals responsible for the degradation of VOC. • The heterogeneous photo-Fenton process is sustainable for multiple reuse of the catalyst. - Abstract: In this work, the performance of benzene, toluene, ethylbenzene, and xylene (BTEX) removal and degradation from gas, air streams on UV pretreated Fe-ZSM-5 in a batch reactor at room temperature were studied. The Fe-ZSM-5 zeolite catalyst was prepared by hydrothermal reaction method. The influence of UV pre-irradiation time on the removal of BTEX were assessed by varying the time, ranging from 15 min to 60s min. Then, sustainability of the activation of the catalyst resulted by UV pretreatment was studied by the four-cycle experiment with one time UV irradiation and after each cycle irradiation followed by BTEX removal after every cycle respectively. The results of BTEX removal depicted that 30 min of UV pretreatment was sufficient for complete organics removal. The UV pretreatment effect on the catalytic oxidation and the stability of the catalyst were studied by modern instrumental techniques. The novelty of the process was the sustainable reuse of catalyst with persistent VOC removal, which works on the -adsorption-oxidation-regeneration-adsorption- cycle, which was confirmed by the characterization studies of the catalyst after four runs. The results revealed that the change in the structure, stability, morphology, and removal efficiency of the catalyst during the experiments was negligible. The VOC degradation mechanism studies showed that the oxidation occurs due to the formation of free radicals as well as hydroxyl ions, so named it heterogeneous photo-Fenton oxidation. The residual materials analysis showed the complete mineralization of VOC except small amount of acetone as oxidation product. Lastly, the kinetics of the VOC removal was studied.