Green production of biologically active Ag and Ag-Cu nanoparticles from Prosopis cineraria pod waste extract and their application in epoxidation

The main focus of the current research is bio-nano-technologically produced nanoparticles (NPs) utilizing waste materials. There is a need for developing advanced technology to reduce waste in an eco-friendly way. Therefore, presently the discarded aqueous portion of Prosopis cineraria pod was used after boiling, to synthesize Ag and Ag-Cu NPs. FT-IR spectra illustrated the presence of phenyl propenoids and flavonoids displaying capping as well as reducing properties. TEM and SEM imaging exhibited an average size of Ag NPs (14 nm) and Ag-Cu NPs (27 nm). The crystallinity nature was confirmed by XRD, and the Cu in Ag-Cu NPs was validated through energy-dispersive X-ray analysis. According to the antimicrobial data, Saccharomyces cerevisiae displayed a zone of inhibition (ZOI) of 42.85% (Ag NPs) and 33.98% (Ag-Cu NPs) at lower concentrations (0.0321 mg/ml), while Bacillus subtilis was found most susceptible (85% ZOI) to Ag NPs at 0.5 mg/ml concentration. Further, these NPs (Ag and Ag-Cu) were utilized in the epoxidation of alkene moieties. Ag NPs showed lower conversion (65%), while Ag-Cu NPs were very active for epoxidation of linalool (93% conversion), suggesting the presence of Cu-facilitated epoxidation. To the best of our knowledge for the first time, aqueous waste is applied to prepare green NPs that can be used as antimicrobial agents and in the synthesis of platform chemicals (epoxide) for industrial aspects. These inexpensive ways of producing green NPs have been utilized several times and have found potential applications in nano-medicine, therapeutics, and modification of monoterpenoids to fine fragrance.

Automated summary

The current research focuses on using waste materials to produce nanoparticles in an environmentally friendly way. In this study, the discarded aqueous portion of Prosopis cineraria pod was used to synthesize Ag and Ag-Cu nanoparticles, which showed small size and antimicrobial properties. Furthermore, these nanoparticles were found to be effective catalysts for the epoxidation of alkene moieties, particularly Ag-Cu nanoparticles with copper-facilitated epoxidation. This inexpensive and green method of producing nanoparticles has potential applications in various industries and medicine.