Engineered Biochar: Novel Silver Loading onto Biochar Using Agri-waste Extract Assisted by LED Light for Catalyst and Antibacterial Capabilities

Engineered biochar can potentially increase its applications in various industries, such as agriculture, wastewater treatment, catalysis, medicine, and environmental remediation. Thus, the development of new and green synthesis techniques is still required. Herein, the green synthesis of rice husk biochar loaded with well-defined silver nanoparticles using an agro-industrial waste extract assisted by blue LED light is presented. Silver zero-valent nanoparticles were successfully attached to the biochar surface, showing excellent dispersion without affecting its textural properties. Impregnated materials were tested as catalysts in a dye reduction process and for antibacterial activity. The RH_B_0.15_Ag material demonstrates excellent dispersion and arrangement of silver particles in the biochar, showing better dispersion than traditional methods. The particle size distribution is 104.66 ± 31 nm, with a specific surface area of 5.97 m² g⁻¹. Lower extract concentrations lead to the formation of smaller particles attached to the biochar surface. The catalytic essay indicates that a smaller particle size distribution achieves faster methyl orange reduction, with 95% of the methyl orange reduced within 5 min. Moreover, the materials showed potential antibacterial effects against Staphylococcus aureus with a zone of inhibition of 19.64 ± 0.247 mm, though no activity was observed against Escherichia coli and Pseudomonas aeruginosa. Graphical Abstract: (Figure presented.)