Ultrasound-assisted heterogeneous process for organic dye pollutants destruction using the novel MIL-101(Fe)/ZrO2/MnFe2O4 nanocomposite catalyst from water medium

Abstract

The heterogeneous sonocatalysis is considered as an impressive remediation approach to eliminate the dyeing wastewaters. Among the efficient sonocatalytic remediation, nanocomposite sonocatalysts have grabbed special attention in recent years. In the presence research, the novel MIL-101(Fe)/ZrO₂/MnFe₂O₄ nanocomposite as a magnetically retrievable catalyst was elaborated using the ultrasound-assisted hydrothermal route and its sonocatalytic performance was tested applying the methylene blue (MB), rhodamine B (RhB), congo red (CR), and methyl orange (MO) organic dyes under US/H₂O₂ system. The as-fabricated nanocomposite is well identified via FESEM, TEM, EDX, EDX elemental dot mappings, AFM, FTIR, XRD, BET, UV-Vis DRS, and VSM. The sonocatalytic destruction outcomes have demonstrated that the MIL-101(Fe)/ZrO₂/MnFe₂O₄ shows appreciable performance for the destruction of MB, RhB, CR, and MO with the yields of 98.17%, 96.35%, 93.40%, and 89.82%, respectively under the optimized conditions of irradiation time of 7 min, dye concentration of 25 mg/L, catalyst amount of 10 mg, US power intensity of 100 W, H₂O₂ concentration of 4 mM, pH of 7, and temperature of 25 ± 1 °C. The fitted kinetic curves were exhibited a first-order model and the half-life time (t_1/2) and reaction rate constant (k_app) of the MB sonodestruction were determined to be 1.20 min and 0.5768 min⁻¹ employing the MIL-101(Fe)/ZrO₂/MnFe₂O₄/US/H₂O₂ system, respectively. The free ^•OH radicals were having a crucial role in the MB sonodestruction reaction, affirmed via quenching the experiments. Besides, the reusing experiments indicate that the MIL-101(Fe)/ZrO₂/MnFe₂O₄ represents propitious stability and long durability and reminded more than 93% after four cycles.

Graphical Abstract

The metal-organic framework MIL-101(Fe)/ZrO₂/MnFe₂O₄ heterojunction magnetically retrievable nanocomposite was successfully prepared and used as a new sonocatalyst for the destruction of MB, RhB, CR, and MO toxic organic dye pollutants from water medium.