Pomegranate Peel And Pomegranate Leaf Aqueous Extract Mediated Synthesis Of Silver Nanoparticles And Their Potential Applications

The green synthesis of noble metal nanoparticles have attracted great attention nowadays,due to their a series of unique properties in optics?electrics?magnetics and energetics.Compared with the traditional chemical and physical methods of synthesizing metal nanomaterials,the bioreduction methods based on plants or microorganisms have emerged as cost-effective,environmentally friendly and easy-to-operate approaches,which can make full use of rich bioresources and produce stable nanoparticles protected by certain biocomponents in biomass.Pomegranate peel and pomegranate leaf are rich in many active ingredients,but they are always considered as waste and abandoned anywhere.In this paper,the aqueous extract of pomegranate peel and pomegranate leaf act as both reducing and stabilizing agent for the synthesis of Ag NPs and based on these Ag NPs the research included the detection of metal ions?antibacterial activity and catalytic activity.The main contents are as follows:1.Pomegranate peel and pomegranate leaf aqueous extract mediated synthesis of silver nanoparticles and their characterization analysisThe aqueous extract of pomegranate peel and pomegranate leaf was used as reducing and stabilizing agents for PPAE-Ag NPs and PLAE-Ag NPs synthesis from Ag NO3 solution.Ag NPs were analyzed by UV-vis spectroscopy,transmission electron microscopy(TEM),Fourier transform infrared spectroscopy(FT-IR),X-ray diffraction(XRD),Thermogravimetric(TG)and Zeta Potential.The influence of different pomegranate peel and pomegranate leaf usage amount,different temperature and different Ag NO3 concentration were investigated by UV-vis,and the size and shape of Ag NPs were observed by TEM.Finally,we obtained the optimum condition of synthesis of PPAE-Ag NPs and PLAE-Ag NPs respectively.2.PPAE-Ag NPs and PLAE-Ag NPs are applied in colorimetric detection of Hg2+The yellowish-brown color and unique optical properties of Ag nanomaterials are due to the effect of localised surface plasmon resonance(LSPR).Upon the addition of Hg2+,the change of color could be observed in PPAE-Ag NPs,but there was no change in PLAE-Ag NPs.At the same time,UV-vis spectrum analysis was used to check a corresponding intensity decrease and a slight blue shift of PPAE-Ag NPs,while the UV-vis of PLAE-Ag NPs had no change.Then we applied PPAE-Ag NPs to detection of Hg2+,under the optimal experimental conditions,the linear response ranges for Hg2+ were from 2?M to 50?M with a detection limit(DL)of 6.6×10-7 mol·L-1.The regression equation is A=0.9410-0.0019C(A represents absorbance of PPAE-Ag NPs,C represents concentration of Hg2+).The selectivity of this method for Hg2+ has been evaluated through testing the response of the assay to various metal ions,including Na+,K+,Mg2+,Zn2+,Ni2+,Mn2+,Co2+,Ba2+,Pb2+,Sr2+,Ca2+,Cd2+,Al3+,Sn2+ at a concentration of 10-2 mol/L.At the same,this present method was successfully used for the determination of Hg2+ ions in environmental water samples.3.The study of antibacterial activity and catalytic activity of PPAE-Ag NPs and PLAE-Ag NPsWe used the method of drilling hole to investigate the antimicrobial activities of PPAE-Ag NPs and PLAE-Ag NPs against Staphlococcus aureus(SA),Escherichia Coli(EC),Extended spectrum ?-Lactamases Staphlococcus aureus(ESBLs-SA)and Extended spectrum ?-Lactamases Escherichia Coli(ESBLs-EC).Results show that both PPAE-Ag NPs and PLAE-Ag NPs have better inhibition effect on gram negative bacteria than positive bacteria.We applied PPAE-Ag NPs and PLAE-Ag NPs to the reduction of 4-nitrophenol(4-NP)to 4-aminophenol(4-AP),as a kind of catalyst.The results show that only PLAE-Ag NPs have catalytic activity and its first-order kinetics constant was 8.64×10-3s-1.In conclusion,the PLAE-Ag NPs could function as an effective green catalyst.