Kumar Vijay, Singh Devendra K, Mohan Sweta, Bano Daraksha, Gundampati Ravi Kumar, Hasan Syed Hadi
Nano Material Research Laboratory, Department of Chemistry, Indian Institute of Technology (BHU), Varanasi 221005, U.P., India.
Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, AR 72701, USA.
J Photochem Photobiol B. 2017 Mar;168:67-77. doi: 10.1016/j.jphotobiol.2017.01.022. Epub 2017 Jan 31.
An ecofriendly and zero cost approach has been developed for the photoinduced synthesis of more stable AgNPs using an aqueous extract of Murraya koenigii (AEM) as a reducing and stabilizing agent. The exposed reaction mixture of AEM and AgNO to sunlight turned dark brown which primarily confirmed the biosynthesis of AgNPs. The biosynthesis was monitored by UV-vis spectroscopy which exhibited a sharp SPR band at 430nm after 30min of sunlight exposure. The optimum conditions for biosynthesis of AgNPs were 30min of sunlight exposure, 2.0% (v/v) of AEM inoculuam dose and 4.0mM AgNO concentration. TEM analysis confirmed the presence of spherical AgNPs with average size 8.6nm. The crystalline nature of the AgNPs was confirmed by XRD analysis where the Bragg's diffraction pattern at (111), (200), (220) and (311) corresponded to face centered cubic crystal lattice of metallic silver. The surface texture was analyzed by AFM analysis where the average roughness of the synthesized AgNPs was found 1.8nm. FTIR analysis was recorded between 4000 and 400cm which confirmed the involvement of various functional groups in the synthesis of AgNPs. On the basis of the linear relationship between SPR band intensity and different concentration of Hg, the synthesized AgNPs can be used for colorimetric detection of Hg with a linear range from 50nm to 500μM. Based on experimental findings, an oxidation-reduction mechanism between AgNPs and Hg was also proposed.
已开发出一种环保且零成本的方法，使用九里香（Murraya koenigii）水提取物（AEM）作为还原剂和稳定剂，通过光诱导合成更稳定的银纳米颗粒（AgNPs）。将AEM和硝酸银（AgNO）的反应混合物暴露于阳光下会变成深棕色，这初步证实了AgNPs的生物合成。通过紫外可见光谱监测生物合成过程，在暴露于阳光下30分钟后，该光谱在430nm处呈现出尖锐的表面等离子体共振（SPR）带。AgNPs生物合成的最佳条件为：阳光照射30分钟、AEM接种剂量为2.0%（v/v）以及硝酸银浓度为4.0mM。透射电子显微镜（TEM）分析证实存在平均尺寸为8.6nm的球形AgNPs。X射线衍射（XRD）分析证实了AgNPs的晶体性质，其中在（111）、（200）、（220）和（311）处的布拉格衍射图案对应于金属银的面心立方晶格。通过原子力显微镜（AFM）分析表面纹理，发现合成的AgNPs的平均粗糙度为1.8nm。傅里叶变换红外光谱（FTIR）分析记录范围在4000至400cm之间，证实了各种官能团参与了AgNPs的合成。基于SPR带强度与不同浓度汞（Hg）之间的线性关系，合成的AgNPs可用于比色法检测Hg，线性范围为50nm至500μM。基于实验结果，还提出了AgNPs与Hg之间的氧化还原机制。
