variable frequency microwave synthesis of silver nanoparticles:
WongVariable frequency microwave synthesis of ..
Abstract Synthesis of silver nanoparticles based on a polyol process and variable frequency microwave (VFM) was investigated. Comparing to a thermal method, the reaction by VFM radiation was much faster. The effects of silver nitrate concentration, poly(N-vinylpyrrolidone) (PVP) concentration, reaction time and reaction temperature were studied. It was found that the higher concentration of silver nitrate, longer reaction time and higher temperature increased the particle size while the higher concentration of PVP decreased the particle size.
Microwave-assisted synthesis of silver nanoparticles …
While the scores of previous studies focused on establishing effective procedures for the synthesis of specific NPs in batch-type systems, we are familiar with only a few reports on the continuous reaction systems, contributing to the development of synthetic methodologies of metal NPs adaptable to industrial needs (Gold et al. ; Horikoshi et al. ; Nishioka et al. ). Therefore, we deemed it important to carry out more systematic studies of the continuous-flow metal NPs’ synthesis using an originally designed reactor with uniform MW irradiation. In this paper, we report the results of silver nanoparticle synthesis to propose a methodology rather than a direct fabrication procedure, based on understanding the mechanisms of their formation, and not just shear experimental findings. We studied the effects of main process and reaction system variables: precursor type and its concentration, temperature, residence time, and also density of MWs’ power input, on the formation of AgNPs to elucidate the mechanisms of their rapid synthesis. In effect, we identified and clarified some of the observed characteristics of AgNPs using the classical LaMer–Dinegar (LMD) (LaMer and Dinegar ) mechanism of NPs’ formation, but seen from a nonisothermal, continuous-flow perspective. Owing to considerable interest in AgNPs as antibacterial agents, we also examined antibacterial properties of the AgNPs-based suspensions, directly obtained from the reported continuous process.