Optimizing Photocatalytic Efficiency and Durability of Zeolite-Based Catalysts via Cation Doping for Effective Dye Contaminant Removal

Abstract

Decoration of Ce and Fe in the dealuminated Y zeolite (DAZY) framework occurred using the isomorphous substitution method in two steps post-synthesis. At first, Y zeolite was dealuminated by EDTA treatment, creating vacant T sites and silanol groups followed by an exchange of Ce and Fe impregnation of the resultant DAZY zeolite with cerium (IV) sulfate and ferric nitrate in one step due to their solubility of related salts to the formation of Si-O-Ce and Si-O-Fe bonds. For this purpose, we have selected three distinct ratios of metals/zeolite, which are 1:3, 1:10, and 1:20. An important outcome was achieved with a 1:20 ratio of metals to zeolite, providing strong evidence for the superiority of this configuration. The catalyst was characterized using spectroscopic techniques. The photocatalytic activity was investigated in the degradation of para-nitrophenol. To optimize the process, we conducted the effect of various parameters, including reaction time, catalyst amount, temperature, pH, isoelectric point, and 4-NP concentration on the photodegradation process. The optimal conditions for the removal of 4-nitrophenol were obtained in the presence of DAZY decorated with Fe and Ce under ultraviolet radiation, 40 µL of hydrogen peroxide, 0.03 g of photocatalyst, and a concentration of 5×10-4 M 4-nitrophenol during 90 minutes. Studying Hinshelwood's equations showed that the reaction rate was pseudo-first order. Meanwhile, the reaction rate increases with the increase of the initial concentration. The catalyst can be reused up to five times while maintaining its catalytic activity. COD experiments proved the mineralization of dye contamination.