Flower-like MoS2 microspheres highly dispersed on CoFe2O4/MIL-101(Fe) metal organic framework: a recoverable magnetic catalyst for the reduction of toxic nitroaromatics in water

Abstract

In this study, we report on the synthesis and characterization of novel magnetic MoS₂/CoFe₂O₄/MIL101-(Fe) nanocomposite catalysts designed for the efficient reduction of toxic nitroaromatic compounds, such as nitrophenols and nitroanilines, to their corresponding amines at ambient temperature. The nanocomposites were engineered by integrating metal–organic frameworks (MIL101-(Fe)), flower-like MoS₂ microspheres, and CoFe₂O₄ nanocrystals using a hydrothermal method. The structural and physicochemical properties of the nanocomposites were thoroughly investigated using a suite of analytical techniques, including XRD, FT-IR, FE-SEM, EDX, VSM, BET surface area analysis, and zeta potential measurement. The results demonstrate that the MoS₂/CoFe₂O₄/MIL-101(Fe) nanocomposite exhibits high catalytic activity in the reduction of 4-nitrophenol (4-NP), 2-nitrophenol (2-NP), 2-nitroaniline (2-NA), and 4-nitroaniline (4-NA) to their respective amine derivatives. The conversion rates are notably high, with pseudo-first-order rate constants of 0.386, 0.086, 0.064, and 0.117 min⁻¹, respectively. Specifically, the complete conversion of these pollutants was achieved within 18–21 minutes, demonstrating the exceptional efficiency of the nanocomposite. Furthermore, the study explored the influence of catalyst dosage and reducing agent concentration on the reduction process's effectiveness. Notably, the magnetic nature of the nanocomposite facilitates its facile separation from the reaction mixture using an external magnet, significantly simplifying its recovery and reuse.