Microwave-assisted continuous flow phytosynthesis of silver nanoparticle/reduced graphene oxide composites and related visible light catalytic performance

The creation of an environmentally friendly synthesis method for silver nanomaterials(Ag-NPs)is an urgent concern for sustainable nanotechnology development.In the present study,a novel straightforward and green method for the preparation of silver nanoparti-cle/reduced graphene oxide(AgNP/rGO)composites was successfully developed through the combination of phytosynthesis,continuous flow synthesis and microwave-assistance.Oriental persimmon(Diospyros kaki Thunb.)extracts were used as both plant reducing and capping agents for fast online synthesis of AgNP/rGO composites.The experimental param-eters were optimized and the morphologies of the prepared materials were investigated.The characterization results reveal that spherical AgNPs were quickly synthesized and uni-formly dispersed on rGO sheets using the proposed online system.Fourier transform in-frared spectroscopy analysis confirmed that phenols,flavonoids,and other substances in the plant extracts played a decisive role in the synthesis of AgNP/rGO composites.Using sodium borohydride(NaBH4)degradation of p-nitrophenol(4-NP)as a model,the catalytic activity of the prepared AgNP/rGO materials was evaluated.The complete degradation of 4-NP was achieved within 12 min through the use of AgNP/rGO materials,and the compos-ite had a much better catalytic activity than the bare AgNPs and rGO had.Compared with the conventional chemical method,our online method is facile,fast,cost-efficient,and en-vironmentally friendly.

Kaffir lime leaf extract mediated synthesis,anticancer activities and antibacterial kinetics of Ag and Ag]AgCl nanoparticles

A facile phytosynthesis of Ag/AgCl and Ag nanoparticles (NPs)was developed using a crude water extract of Citrus hystrix DC (kaffir lime)leaves.The phytochemical and chloride contents of the extract,and various synthesis parameters were studied.The obtained Ag/AgCI and Ag NPs were of the cubic phase and mostly spherical in shape,Particle sizes of the yielded NPs were distributed in a narrow range with an average size of 20 and 38nm for the Ag/AgCI and Ag NPs,respectively,The reducing function of the phytochemicals and the stabilizing ability of gelatin were demonstrated,The NPs showed significant antiproliferative activities against the carcinoma HCT 116 and adenocarcinoma Caco-2 colorectal cell lines, but had a negative effect toward human fibroblasts.The NPs exhibited excellent antibacterial activities against Escherichia coil,Staphylococcus aureus,Pseudomonas aeruginosa and Bacillus cereus.The inactivation kinetics obtained in the presence of the NPs showed a biphasic behavior that can be explained by the Cerf model.