Magnetic materials show promising applications in heterogeneous catalysis due to their ease of isolation and excellent reusability. Magnetic nanoparticles have emerged as a promising alternative in biosorbent modification because of their large surface area and adsorption efficiency. These adsorbents are also unique, fertile, compatible, easy to synthesize, economical, and environmentally friendly. They can also be easily extracted from mixtures obtained from adsorption processes. However, the main challenge in applying these magnetic nanoparticles is high cost when using these materials alone. This issue can be solved through combining these materials with biochar. The present study reports the design, synthesis, and characterization of a new magnetic Fe3O4 biochar catalyst. The structures and properties of Magnetic biochar bis(thiourea) triazin copper (II) (MBC@BTT-Cu(II)) were fully characterized using various physicochemical techniques. The prepared catalyst showed excellent catalytic activity for the synthesis of 5-substituted 1H-tetrazole derivatives. This new method shows some important features, including high efficiency, lower catalyst loading, easy operation, and the ability to recycle the catalyst for at least six times without obvious degradation of the catalytic performance. Furthermore, MBC@BTTCu(II) nanocatalyst can be reused in up to five cycles without loss in catalytic activity
