Helichrysum arenarium-mediated facile green synthesis, antibacterial, catalytic activity and hydrogen evolution of metallic (Ag, Cu) and bimetallic (Ag/Cu) nanoparticles

Abstract

Metallic Ag, Cu and bimetallic Ag/Cu nanoparticles (NPs) easily and economically synthesized by green synthesis method using Helichrysum arenarium plant extracts used as reducing agent were characterized with analysis of SEM (Scanning electron microscopy), TEM (Transmission electron microscopy) and BET (Brunauer-Emmett-Teller). The adsorption study of the synthesized nanoparticles for Congo Red (CR) azo dyestuff was carried out and dyestuff removal properties were investigated in detail. At 100 min, the CR removal percentages were found to be 90.2 %, 77.8 % and 66.1 % by Cu NPs, Ag/Cu NPs and Ag NPs, respectively and the adsorption was found to be in accordance with the second order kinetic model and Langmuir isotherm model. In reusability studies of Cu NPs adsorbent, CR removal was found to be 90.2 %, 88.9 % and 83.4 % in three experimental cycles, respectively. For antimicrobial activity of Helichrysum arenarium extract, Cu NPs, Ag/Cu NPs and Ag NPs were used to against 6 pathogenic microorganisms via disc diffusion assay. As a result of the antimicrobial assay, while Helichrysum arenarium extract did not show any effect against the tested pathogenic microorganisms, both Ag NPs and Ag/Cu NPs showed an inhibition zone diameter against the tested pathogenic microorganisms (p < 0.05). It is conceivable that it would be effective in controlling the growth of resistant microorganisms in aqueous media since it produces a similar level of inhibition in methicillin-resistant and non-resistant S. aureus. Finally, the catalytic activity of the synthesized nanoparticles was evaluated in hydrogen (H2) production by hydrolysis of NaBH4. Based on experimental results, the efficiency of hydrogen production was determined as Cu NPs > Ag/Cu NPs > Ag NPs. The optimum conditions for the highest yield of H2 were investigated and the catalysis results were compared with sonocatalysis. This research shows that NPs can be synthesized in a simple, economical and environmentally friendly way and has a wide range of uses.