Department of Chemical Engineering, Lee Kong Chian Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, 43000, Kajang, Selangor, Malaysia.
Nanotechnology & Catalysis Research Centre (NANOCAT), Institute of Graduate Studies Building, University of Malaya, 50603, Kuala Lumpur, Malaysia.
Environ Sci Pollut Res Int. 2020 Oct;27(28):34675-34691. doi: 10.1007/s11356-019-06583-z. Epub 2019 Oct 18.
Nowadays, the current synthesis techniques used in industrial production of nanoparticles have been generally regarded as nonenvironmentally friendly. Consequently, the biosynthesis approach has been proposed as an alternative to reduce the usage of hazardous chemical compounds and harsh reaction conditions in the production of nanoparticles. In this work, pure, iron (Fe)-doped and silver (Ag)-doped zinc oxide (ZnO) nanoparticles were successfully synthesized through the green route using Clitoria ternatea Linn. The optical, chemical, and physical properties of the biosynthesized ZnO nanoparticles were then analyzed by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDX), UV-Vis diffuse reflectance spectroscopy (DRS), zeta potential measurement, Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and surface analysis. The biosynthesized ZnO nanoparticles were crystallized with a hexagonal wurtzite structure and possessed smaller particle sizes than those of commercially or chemically produced samples. The existence of biomolecules to act as reducing and stabilizing agents from C. ternatea Linn aqueous extract was confirmed using FTIR analysis. The biosynthesized ZnO nanoparticles mainly comprised of negatively charged groups and responsible for moderately stable dispersion of the nanoparticles. All these properties were favorable for the sonocatalytic degradation of Congo red. Sonocatalytic activity of ZnO nanoparticles was studied through the degradation of 10 mg/L Congo red using ultrasonic irradiation at 45 kHz and 80 W. The results showed that the sonocatalytic degradation efficiency of Congo red in the presence of biosynthesized ZnO nanoparticles prepared at 50 °C for 1 h could achieve 88.76% after 1 h. The sonocatalytic degradation efficiency of Congo red in the presence of Ag-doped ZnO was accelerated to 94.42% after 10 min which might be related to the smallest band gap energy (3.02 eV) and the highest specific surface area (10.31 m/g) as well as pore volume (0.0781 cm/g). Lastly, the biosynthesized ZnO nanoparticles especially Ag-doped ZnO offered significant antibacterial potential against Escherichia coli which indicated its ability to inhibit the normal growth and replication of bacterial cells. These results affirmed that the biosynthesized ZnO nanoparticles could be used as an alternative to the current chemical compounds and showed a superior sonocatalytic activity toward degradation of Congo red.
如今，工业生产纳米粒子中使用的当前合成技术通常被认为是不环保的。因此，生物合成方法已被提出作为替代方法，以减少生产纳米粒子中危险化学化合物和苛刻反应条件的使用。在这项工作中，通过使用三叶车轴草（Clitoria ternatea Linn.）成功地通过绿色路线合成了纯铁（Fe）掺杂和银（Ag）掺杂氧化锌（ZnO）纳米粒子。然后通过 X 射线衍射（XRD）、场发射扫描电子显微镜（FESEM）、能量色散 X 射线光谱（EDX）、紫外可见漫反射光谱（DRS）、Zeta 电位测量、傅里叶变换红外光谱（FTIR）、热重分析（TGA）和表面分析来分析生物合成 ZnO 纳米粒子的光学、化学和物理性质。生物合成的 ZnO 纳米粒子结晶为六方纤锌矿结构，并且具有比商业或化学生产样品更小的粒径。使用 FTIR 分析证实了来自三叶车轴草水提取物的生物分子作为还原和稳定剂的存在。生物合成的 ZnO 纳米粒子主要由带负电荷的基团组成，负责纳米粒子的适度稳定分散。所有这些特性都有利于刚果红的超声降解。通过在 45 kHz 和 80 W 的超声波照射下降解 10 mg/L 的刚果红研究了 ZnO 纳米粒子的超声催化活性。结果表明，在 50°C 下制备 1 小时的生物合成 ZnO 纳米粒子存在下，刚果红的超声催化降解效率在 1 小时后可达到 88.76%。在 10 分钟内，Ag 掺杂 ZnO 的存在加速了刚果红的超声催化降解效率达到 94.42%，这可能与最小的带隙能（3.02 eV）、最高的比表面积（10.31 m/g）和孔体积（0.0781 cm/g）有关。最后，生物合成的 ZnO 纳米粒子特别是 Ag 掺杂 ZnO 对大肠杆菌表现出显著的抗菌潜力，表明其能够抑制细菌细胞的正常生长和复制。这些结果证实了生物合成的 ZnO 纳米粒子可以替代当前的化学化合物，并表现出对刚果红降解的优越超声催化活性。
