Synthesis of Ag-Ag2O nanoparticles using Ageratum conyzoides leaf extract for the catalytic reduction of nitrobenzene and methylene blue and antibacterial applications

The 4-nitrophenol (4-NP) and methylene blue (MB) are commonly used in many industries and remain in the industrial effluent. They have an adverse effect on the environment if not treated properly. Therefore, it is essential to develop a convenient method to remove such toxic chemicals from wastewater. Here, Ag/Ag2O nanoparticles (NPs) were prepared from AgNO3 (0.05 M) using Ageratum conyzoides L. agricultural weed extract (50 mL) in an ultrasonic bath. Then, the synthesized Ag/Ag2O NPs were utilized for the 4-NP and MB reduction in the presence of NaBH4. The Ag/Ag2O NPs efficiently reduce 4-NP to 4-AP and MB to LMB in an aqueous medium. In the case of 4-NP, about 93% of the reduction was achieved in about 10 min at optimum conditions, 2 mL of 4-NP (0.15 mM) and 100 μL of NaBH4 (50 mM) in the presence of 1 mg Ag/Ag2O NPs. About 94% reduction of MB dye was achieved in about 6 min at optimum conditions, 2 mL of MB (10 ppm) and 100 μL of NaBH4 (30 mM) using 1 mg Ag/Ag2O NPs. Furthermore, the bactericidal activity of Ag/Ag2O NPs was studied against S. Mutans, B. Subtilis, and E. coli.