Innovative synthesis of nano-magnetic bio-organocatalysts from red mud waste for green polyhydroquinoline derivatives...

The imperative of transforming waste materials into valuable nanomaterials via ecological recycling has emerged as a pivotal avenue for environmental stewardship. This research contributes to the "greening" of global chemical processes by introducing a magnetic biocatalyst derived from red mud waste. Emphasizing the use of glutamic acid as the second most effective step in obtaining a green catalyst is a key focus of this work. Leveraging cost-effective materials such as FeSO₄, amino acid, and Fe₂O₃ isolated from red mud enhances the economic viability of the synthesized catalyst. Characterization of the newly developed nano-magnetic bio-organocatalysts was conducted using advanced spectroscopic techniques, including Fourier transform infrared (FT-IR), X-ray diffraction (XRD), Transmission Electron Microscopy (TEM), field emission scanning electron microscopy (FE-SEM), Brunauer-Emmett-Teller (BET), energy-dispersive X-ray spectroscopy (EDX), mapping, thermogravimetric analysis (TGA), and vibrating-sample magnetometers (VSM). The catalytic activity of Fe₃O₄@SiO₂@(CH₂)₃@Gl was examined in the one-pot synthesis of polyhydroquinolines, showcasing short reaction times, high efficiency, ease of catalyst separation, and the potential for catalyst recycling as salient features of this work. This study pioneers the utilization of red mud waste for eco-friendly nanomaterial synthesis and underscores the economic and environmental significance of incorporating glutamic acid as a crucial element in the catalyst synthesis process.