Fe/Acid‐montmorillonite as effective Fenton‐like catalyst for the removal of methylene blue

Abstract Background Most dyes are toxic, carcinogenic, and mutagenic, all of which cause severe harm to human health and the environment. Therefore, it is essential to find the most suitable method to treat dye wastewaters before discharge. In this study, the natural Ca‐type montmorillonite (Ca‐MMT) was activated by HNO 3 (20 wt.%) solution under different temperatures to obtain acid‐activated MMT (Acid‐MMT). Fe (10 wt.%) was supported on Acid‐MMT (Fe/Acid‐MMT) via the impregnation method using Fe(NO 3 ) 3 ·9H 2 O as a precursor. Meanwhile, the removal of methylene blue (MB) by heterogeneous Fenton‐like reaction using Fe/Acid‐MMT as catalyst was evaluated. The material was characterized by Fourier transform infrared spectroscopy (FT‐IR), X‐ray diffraction (XRD), X‐ray photoeletron spectroscopy (XPS), scanning electron microscopy (SEM), N 2 adsorption–desorption at low temperature, and the temperature program desorption of NH 3 (NH 3 ‐TPD) techniques. Results The acidity and textural properties of the Acid‐MMT were adjusted by varying the acid activation temperature. Moreover, the amount of acidity and the surface area of the catalyst had a noticeable effect on the removal efficiency of MB. Fe‐supported Acid‐MMT activated by HNO 3 at 100°C (Fe/Acid‐MMT‐100) catalyst exhibited the highest removal efficiency of MB. The removal efficiency of the MB was more than 97.8% under the following reaction conditions: H 2 O 2 concentration of 0.85 mmol·L −1 , Fe/Acid‐MMT‐100 dosage of 0.75 g°L −1 , temperature of 50°C, and initial solution pH of 3.0–9.0. Conclusion An efficient Fe/Acid‐MMT catalyst for a Fenton‐like reaction was obtained by optimizing the acid treatment temperature of Ca‐MMT. The synergistic effect between its excellent adsorption ability and the ∙OH generated from H 2 O 2 activated by Fe/Acid‐MMT would enhance MB removal efficiency in a Fenton‐like system. © 2022 Society of Chemical Industry (SCI).