An application study of MnCoFe₂O₄@PEG-4000 (MCF@PEG-4000) MNPs as a catalyst in the synthesis of hexahydroquinolines and benzopyrans and as an nano-adsorbent for the removal of Cu (II) and Fe (III) ions in aqueous solutions

The novel MnCoFe₂O₄@PEG-4000 was synthesized by a simple and clean method. These nanoparticles have an almost spherical structure with an average diameter of about 21.95 nm, a saturation magnetization (Ms) of about 26.31 emu/g, and a thermal stability of about 100 °C. The application of these nanoparticles as a reusable green catalyst in the synthesis of hexahydroquinolines and benzopyrans and also as a nano-adsorbent for the removal of copper (II) (Cu (II)) and iron (III) (Fe (III)) metal ions in aqueous solutions was investigated. The use of a relatively green solvent, short reaction times, and high yield of products under optimal conditions are some of the advantages of these synthetic procedures for the preparation of hexahydroquinolines and benzopyrans in the presence of MCF@PEG-4000 MNPs as a catalyst. The adsorptive removal progress was optimized at pH = 7, the adsorbent dosage of 10 mg, and a contact time of 30 min. For the removal of both ions, the use of natural pH (7) is an important advantage of this work. The adsorption capacity (qe) of MnCoFe₂O₄@PEG-4000 MNPs for copper (II) and iron (III) was found to be about 149.9 mg/g and 599.67 mg/g, respectively, according to the second-order pseudo-models. Also, it was found that MCF coated with PEG is a better adsorbent for the adsorptive removal of metal ions than MCF due to the cover of PEG.