Natural zeolites supported green-synthesized CeО₂@Polybenzimidazole hybrid materials for dye degradation

Natural zeolites, clinoptilolite from the Golobradovo deposit, Bulgaria, and mordenite from the Lyaskovets deposit in Eastern Rhodopes, Bulgaria, were used for the preparation of natural-zeolite-supported CeО₂@Polybenzimidazole (PBI) hybrid materials with green-synthesized ceria incorporated using Veronica officinalis L. plant extract. In order to prepare hybrid composite powders of the natural zeolites/green-synthesized CeО₂, the surface was impregnated with the use of ethanolic KOH solution of meta-polybenzimidazole as dispersant media. The chemical and phase composition, structure, and thermal behavior of the obtained composite materials were investigated through X-ray fluorescence analyses, powder X-ray diffraction, Fourier-transform infrared spectroscopy, and thermogravimetric analysis. The presence of CeO₂ (33.1 mass % and 32 mass %) in the prepared clinoptilolite- or mordenite-supported green-synthesized CeО₂@Polybenzimidazole was determined using X-ray fluorescence analysis. The photocatalytic properties of the synthesized hybrid materials were tested in the reaction of oxidative photocatalytic degradation of 5 ppm Reactive Black 5 (RB5) dye as a model pollutant under UV light irradiation. The photocatalytic results show that the RB5 dye demonstrates a higher degree of degradation (98%) with 120 minutes of UV irradiation in the presence of mordenite-supported/CeO₂@PBI as the photocatalyst compared to that with the clinoptilolite-supported/CeO₂@PBI (14%).

Acknowledgments: The authors express their gratitude to the project with the Bulgarian National Science Fund, KP-06-N69/8 (КП-06-Н69/8), “Novel polymer-hybrid materials containing (bio)synthesized metal oxide particles with improved photocatalytic and antimicrobial potential”, for the financial support. The authors acknowledge the technical support from the project PERIMED BG05M2OP001-1.002-0005 /29.03.2018 (2018–2023). Thanks to Liliya Tsvetanova for her technical assistance in the XRF analysis.