Continuous-Flow Biosynthesis of Silver Nanoparticles by Lixivium of Sundried Cinnamomum camphora Leaf in Tubular Microreactors

Abstract

Biological production of silver nanoparticles by lixivium of sundried Cinnamomum camphora leaf in continuous-flow tubular microreactors was investigated. Properties of silver nanoparticles were examined by transmission electron microscopy (TEM), UV-vis spectroscopy, X-ray diffraction (XRD), and energy dispersive X-ray (EDX). The concentration of residual silver ions after reaction was measured by atomic absorption spectophotometry (AAS) spectroscopy. Fourier transform infrared (FTIR) spectra of C. camphora leaf lixivium were analyzed and temperature profiles along the tubes were calculated to explore formation mechanism of silver nanoparticles. Comparison of FTIR spectra of C. camphora leaf lixivium before and after reaction demonstrated the polyols in the lixivium may be mainly responsible for reduction of silver ions. According to the temperature profiles, at the inlet of the microreactors at 90 °C, the soar of the fluid temperature induced the burst of silver nuclei by homogeneous nucleation. Subsequently, the nuclei grew gradually along the reactors into silver nanoparticles from 5 to 40 nm. Polydisperse particles were formed by combination of heterogeneous nucleation and Ostwald ripening along the tubes at 60 °C.

A Review of Silver Nanoparticles: Research Trends, Global Consumption, Synthesis, Properties, and Future Challenges

“…For industrial scale‐up, the production should be continuous because it is critically related to the operational cost. A prototype using a continuous flow tubular microreactor has been considered as an alternative . In the flow reactor, AgNPs can be produced on a continuous basis once the reaction reaches the steady state.…”

An Overview: Biological Organisms That Serves as Nanofactories for Metallic Nanoparticles Synthesis and Fungi Being the Most Appropriate

“…For example Bacteria like Desulfuromonas acetoxidans, Shewanella spp and Magnetospirillum magnetotacticum produces iron oxide nanoparticles [11]. In addition Copper and Cadmium sulfate nanoparticles were produce by photosynthetic bacteria of genus Serratia and Rhodobacter sphaeroides respectively [12,13] while Escherichia coli is reported to produce Cadmium nanocrystals [14].…”

Green Synthesis of Noble Metal (Au, Ag, Pt) Nanoparticles, Assisted by Plant-Extracts

“…The polyol components and the water-soluble heterocyclic components were mainly responsible for the reduction of silver ions or chloroaurate ions and the stabilization of the nanoparticles, respectively. The process were scaled-up successfully for biological production of silver nanoparticles by lixivium of sundried Cinnamomum camphora leaf in continuous-flow tubular microreactors [29] Silver nanoparticles (NPs) were rapidly synthesized by treating silver ions with a Capsicum annuum L. extract [14]. The reaction process was simple and convenient to handle, and was monitored using ultraviolet-visible spectroscopy (UV-vis).…”