Nagar Niharika, Devra Vijay
Department of Chemistry, J.D.B. Govt. P.G. Girls College, Kota, Rajasthan, 324001, India.
Heliyon. 2019 Mar 20;5(3):e01356. doi: 10.1016/j.heliyon.2019.e01356. eCollection 2019 Mar.
The present study includes the (neem) induced Silver nanoparticles (AgNPs) by green synthesis as reducing and capping agent. Synthesized AgNPs were characterized by different instrumental techniques such as XRD (X-ray Diffraction), SEM (Scanning Electron Microscopy), TEM (Transmission Electron Microscopy), Zetasizer, UV-Visible and FT-IR (Fourier Transformation Infra-Red) spectroscopy. The result of XRD reveals that nanoparticles were crystalline in nature and pure, stability was determined by Zeta potential and SEM, TEM analysis indicates that AgNPs was monodisperse in a spherical shape with average size 9 nm. These synthesized AgNPs were applied as the catalyst in the degradation process of Methyl Orange (MO) and wastewater samples in presence of peroxodisulphate (PDS). Effect of different experimental conditions such as initial pH, concentration of PDS, Dye, and AgNPs was studied on the degradation process. The obtained kinetic result shows that AgNPs/PDS system induces 1.1 × 10 to 15.9 × 10 s folds in presence of the small concentration of AgNPs (1 × 10 mol dm). The degradation of MO and real wastewater samples in AgNPs/PDS system is followed pseudo-first order kinetics and maximum degradation of MO reached 88% in 40 min and real wastewater samples in 80 min. Liquid chromatography-mass spectrometry (LC-MS) analysis and UV-Visible spectral changes were used to analyze the structure of intermediate and end products (CO, HO, NO , and OS) during the degradation process. Furthermore, the result of biodegradability index (greater than 0.3) implies that advanced oxidation process enhances the biodegradability of wastewater.
本研究包括通过绿色合成法利用印楝诱导合成银纳米颗粒（AgNPs），印楝作为还原剂和封端剂。通过不同的仪器技术对合成的AgNPs进行表征，如XRD（X射线衍射）、SEM（扫描电子显微镜）、TEM（透射电子显微镜）、Zetasizer、紫外可见光谱和FT-IR（傅里叶变换红外）光谱。XRD结果表明纳米颗粒本质上是结晶且纯净的，通过Zeta电位测定稳定性，SEM、TEM分析表明AgNPs呈单分散球形，平均尺寸为9nm。这些合成的AgNPs在过二硫酸盐（PDS）存在的情况下被用作甲基橙（MO）和废水样品降解过程的催化剂。研究了不同实验条件如初始pH值、PDS浓度、染料浓度和AgNPs浓度对降解过程的影响。获得的动力学结果表明，在低浓度AgNPs（1×10⁻⁵mol dm⁻³）存在的情况下，AgNPs/PDS体系的降解速率提高了1.1×10⁻²至15.9×10⁻²倍。AgNPs/PDS体系中MO和实际废水样品的降解遵循准一级动力学，MO的最大降解率在40分钟内达到88%，实际废水样品在80分钟内达到。利用液相色谱 - 质谱（LC-MS）分析和紫外可见光谱变化来分析降解过程中的中间产物和最终产物（CO₂、H₂O、NO₃⁻和SO₄²⁻）的结构。此外，生物降解性指数（大于0.3）的结果表明高级氧化过程提高了废水的生物降解性。
