Abstract

Ag nanofluids have been synthesized by the single pot synthesis method reducing silver nitrate (AgNO₃) applying sodium borohydride (NaBH₄) as a reducing agent in the presence of trisodium citrate (TSC) in water base fluid. Stirring effect on the synthesis has been studied in terms of rotation per minute (RPM) using a digitally displayed electronically controlled mechanical stirrer and a decreasing tendency of mean particle sizes has been observed on increasing RPM from 250 to 950 at the interval of 100. Time dependent Surface Plasmon Resonance (SPR) Spectra have been recorded by UV-Visible spectrometer from 1 h to 36 h at the interval of almost 12 h and the particle size distribution have been estimated by the deconvolution of the spectra. The size distribution has been quantified correlating deconvoluted peaks and their area under the curves proportionated to that of the entire spectrum. The mean particle sizes have been observed to vary from 20 nm to 100 nm and the variations depend on both RPM and time. The RPM and time dependent area under the curve of each spectrum have been analyzed to find the nanofluid stabilization and 450 has been recorded as most stabilizing RPM accounting by 0.35% change in it. The histograms of particle size distribution have been analyzed by mathematical modeling, arithmetic progression and geometric progression. Histogram that fits arithmetic progression indicates Ag⁺ seeding by its reduction on Ag nanoparticles to grow bigger particles and histogram that fits geometric progression indicates agglomeration of Ag nanoparticles for sedimentation.

摘要

银纳米流体已通过单锅合成法还原硝酸银 (AgNO ₃ ) 和硼氢化钠 (NaBH ₄ )合成。) 在水基液中柠檬酸三钠 (TSC) 存在下作为还原剂。已经使用数字显示的电子控制机械搅拌器在每分钟转数 (RPM) 方面研究了搅拌对合成的影响，并且观察到平均颗粒尺寸在以 100 为间隔从 250 增加到 950 时平均粒径减小的趋势。从 1 小时到 36 小时，紫外-可见光谱仪以几乎 12 小时的间隔记录了相关表面等离子体共振 (SPR) 光谱，并且通过光谱的解卷积估计了粒度分布。大小分布已被量化，相关解卷积峰及其曲线下的面积与整个光谱的面积成正比。已观察到平均粒径从 20 nm 到 100 nm 不等，变化取决于 RPM 和时间。分析了每个光谱曲线下的 RPM 和时间相关面积，以发现纳米流体的稳定性，450 被记录为最稳定的 RPM，占其变化 0.35%。通过数学建模、等差级数和几何级数分析了粒度分布的直方图。符合等差数列的直方图表示 Ag 等差数列和几何数列。符合等差数列的直方图表示 Ag 等差数列和几何数列。符合等差数列的直方图表示 Ag⁺通过减少在银纳米颗粒上的播种来生长更大的颗粒，符合几何级数的直方图表明银纳米颗粒聚集以用于沉降。