Improved Adsorption Capacity and Photocatalytic Performance of Sr ₂ FeO ₄ Ruddlesden–Popper Oxide

Abstract This article presents an in‐depth study of the first series of Ruddlesden–Popper oxides ( n = 1), focusing specifically on the Sr₂FeO₄ compound prepared via a sol–gel method using the citrate process. This research explores the application of this material as a photocatalyst. The kinetic parameters of methylene blue (MB) removal by Sr₂FeO₄ were evaluated using linear models, including pseudo‐first‐order (PFO), pseudo‐second‐order (PSO), and intra‐particle diffusion. Four error functions‐correlation coefficient (R 2 ), root‐mean‐square error (RMSE), mean‐square error (MSE), and sum of squares error (SSE) were applied to determine the best kinetic fit. The MB removal mechanism was studied and found to follow intra‐particle diffusion kinetics. The effect of various parameters (pH, catalyst mass, irradiation time, etc.) on the removal efficiency of MB was also investigated, and the pH p zc point was evaluated. These results highlight Sr₂FeO₄ as an efficient and inexpensive photocatalyst for the decomposition of pollutants in water under visible light irradiation.