چكيده به لاتين
Due to the different properties of nanoparticles and their application in various industries, many studies have addressed them. Depending on how nanoparticles are produced, their properties will vary in amount, size, and dispersion. In this study, the objective was to produce silver nanoparticles with specific properties using a bottom-up chemical reduction method in a microchannel. The use of microreactors is of higher value than other methods because of the smaller size and thus better mixing. For the production of silver nanoparticles, two solutions of silver nitrate and sodium borohydride with a specific concentration ratio are used. In the numerical method, using the COMSOL software, after obtaining the optimum geometry, the effect of various parameters such as inlet discharge rate, concentration ratio and temperature on the amount of silver produced in the output was investigated. The results indicated that by reducing the flow rate and increasing the ratio of sodium borohydride to silver nitrate concentration, there would be more time for reaction and the amount of silver nanoparticles in the output would be higher. After numerical study, according to the optimum geometry obtained, the microchannel was made using PDMS and then glued on glass. In the experimental work, by changing the flow rate of the inlet solutions, the concentration and temperature ratios, the number of nanoparticles produced, their dispersion and the size of the nanoparticles at the output were investigated using spectrometer data. These results show the effect of lowering temperature on lower dispersion and smaller size of the produced silver particles such that at zero temperature with a concentration of 6 to 1 sodium borohydride to silver nitrate and an inlet flow rate of 3.6 ml/h a yellow color solution by 23 nm silver nanoparticles was produced. By examining the same sample inside the SEM, a good image was obtained of the uniform particle production, which by means of image processing and averaging of the particle size was 22.2 nm, which was close to the number obtained by the spectrometer.
