Novel Synergistic Synthesis of Ni-Doped Fe₃O₄ Nanocomposite: Adsorption Interactions with Heavy Metal Ions and Antimicrobial Studies of Hantzsch Products

This study explores the synthesis, catalytic performance, and dual functionality of Ni@Fe₃O₄ nanoparticles as both reusable catalysts and adsorbents for heavy metal ions. The Ni@Fe₃O₄ nanoparticles efficiently catalyzed the one-pot synthesis of 1,4-dihydropyridine (1,4-DHP) derivatives, achieving high yields (89%-96%) with excellent purity, as confirmed by advanced spectroscopic techniques. The synthesized 1,4-DHP derivatives, particularly those with polar groups at the para position (compounds <b>3d</b>, <b>3e</b>, and <b>3f</b>), exhibited significant antimicrobial activity comparable to that of standard pharmaceutical drugs. Additionally, the Ni@Fe₃O₄ nanoparticles exhibited high efficiency in adsorbing Pd-(II) and Cu-(II) ions, with optimal performance at a dosage of 0.07 g and pH 4, driven by enhanced protonation at acidic pH. The adsorption isotherm studies indicated a higher affinity for Pd-(II), reaching a maximum adsorption capacity of 968.18 mg/g, while Cu-(II) achieved 758.99 mg/g. These results underscore the versatility of Ni@Fe₃O₄ nanoparticles as promising multifunctional materials for applications in organic synthesis, antimicrobial treatments, and environmental remediation of heavy metals.