Controlled Production of Monodisperse Plant‐Mediated AgNP Catalysts Using Microwave Chemistry: A Desirability‐Function‐Based Multiple‐Response Optimization Approach

Abstract

This study introduces a new straightforward strategy for screening the formation of catalytically active and monodisperse silver nanoparticles (AgNPs) using Epilobium parviflorum green tea extract and microwave technology. The method facilitates from multivariate statistical analysis for the optimization of the reaction conditions at which the produced AgNPs exhibit the best catalytic response for the model reduction reaction of 4‐nitrophenol (4‐NP). A five‐level two‐factor Central Composite (CCD) design of experiments (DOE) together with a response surface methodology (RSM) based desirability function approach was applied for the optimization of two variables, which are microwave exposure time and amount of silver nitrate, to obtain the desired monodisperse AgNPs displaying the best catalytic activity with the green and biogenic synthesis methods. The overall desirability of 82.2% for the measure of dispersity function of AgNPs (ψ ) and the first‐order‐reaction rate constants (kapp ) were obtained. The nanospheres with the TEM mean diameter of 19.10±2.06 nm were successfully synthesized in the optimized conditions: 15 min of microwave exposure time and 4 mL of AgNO3 (10 mM) at 100 °C with a laboratory‐grade microwave reactor and the formed nanoparticles were fully characterized. Verification experiments (ψ=3.546×105 and kapp=0.0293 s−1) confirmed the validity of the predicted model (ψ=3.567×105 and kapp=0.0291s −1) (p<0.05).

Antimicrobial and Antibiofilm Activities of New Synthesized Silver Ultra-NanoClusters (SUNCs) Against Helicobacter pylori

“…A drastic decrease of the plasmonic spectrum absorbance, without change of the λ max , was observed after nitric acid treatment (0.1 M, pH < 1) for 10 min at 25°C. The complete disappearance of the SUNCs UV-Vis spectrum is obtained after 60 min of nitric acid (0.1 M final concentration) reaction at 60°C ( Supplementary Figure S1 ; Ertürk, 2019 ). After each synthesis, large nanoclusters were removed by flushing the solution through 0.1-μm syringe filter devices (Whatman CYCLPR) and subsequent centrifugation at 13,023 × g for 15 min.…”

“…Only after nitric acid treatment (pH < 1) for 1 h at 60 • C was a complete disappearance of the plasmonic spectrum, without a shift of the λ max , obtained. It is very likely that these drastic conditions can induce the complete oxidation of metal silver in Ag + without macroaggregate formation (Ertürk, 2019).…”

In situ green synthesis of MnFe2O4@EP@Ag nanocomposites using Epilobium parviflorum green tea extract: An efficient magnetically recyclable catalyst for the reduction of hazardous organic dyes

“…Separation of the synthesized MRNCs from the suspended solution by an external magnet is an important feature as it provides fast recovery with low cost. In order to ensure the repeated use of the catalyst and effective surface area, a synthesis of manganese ferrite, which exhibits relatively high magnetization among other ATR-FTIR is a feasible technique for both the determination and the characterization of the presence of polyphenols in the green tea extract that might be responsible for the coating and the stabilization of metal nanoparticles [51,52]. On the basis of this aim, the ATR-FTIR spectroscopy was used to evaluate the variations in the structure of the MnFe 2 O 4 NPs after coating with the EP extract and while forming MnFe 2 O 4 @EP@Ag MRNCs.…”

In situ deposition of silver nanoparticles on polydopamine‐coated manganese ferrite nanoparticles: Synthesis, characterization, and application to the degradation of organic dye pollutants as an efficient magnetically recyclable nanocatalyst

“…Based on this strategy, noble metal‐based catalysts involving platinum, palladium, gold, and silver have generated a considerable research field for the treatment of wastewater. [ 8–18 ] Among these catalysts, silver nanoparticles (AgNPs) have attracted significant interest due to their preferable lower costs, high catalytic and optical activities, and antibacterial properties. [ 12,19,20 ] However, agglomeration due to their high surface energy and van der Waals forces and the decline in their catalytic performance can be a great handicap for their widespread of applications, unless they are preserved.…”