Enhanced Photocatalytic Removal of Congo Red Dye From Water Environment Using Eggshells Infused With Graphitic Carbon Nitride Composites.

Eggshell (ES)‐based photocatalysts have gained attention in recent years. They are less toxic, abundant, affordable, and efficient photocatalysts in treating dye‐polluted water. This work reports the deterioration of Congo red (CR) under visible light region using ES‐integrated graphitic carbon nitride (g‐C3N4). The photocatalyst was prepared by thermal condensation by varying the mass ratios of ES powder. The material structure and the morphological characteristics are confirmed using FTIR, XRD, BET, UV‐DRS, UV‐Vis spectra, SEM, EDAX, and photoluminescence. By optical investigations, the band gap of bare ES was found to have a value of 5.04 eV. It was narrowed down to 2.57 eV at the optimum composition of ES/g‐C3N4. The effects of several reaction parameters, such as the initial concentration of dye, the amount of catalyst, and the pH level of the solution on the photodegradation rate were investigated. The degradation results revealed that the catalyst removed around 90.5% of the CR dye in 90 min at 498 nm when subjected to visible light. A pseudo‐first‐order model was concluded from the kinetic data analysis of the mineralization of CR dye using carbon nitride photocatalysts infused with eggshells. The photodegradation rate of 5% ES g‐C3N4 was three times greater than that of pure g‐C3N4, indicating a decreased recombination rate of the electron‐hole pair. [ABSTRACT FROM AUTHOR]