Low-power ultrasonic cleaner challenged the “submicron” particle detachment. 難問の「数百nm粒子の剥離」に低出力の超音波洗浄機が挑戦した


新しい微粒子の回収法 (a novel particle collector system)

FREE ACCESS: doi.org/10.1252/jcej.16we319

研究室の発表論文の紹介(Introduction of papers from our group) >> https://tag/paper/

100 nm から1μm(sub-micron)粒子は大気中に浮遊する物質の中で最も高い個数濃度であり、その観測や化学分析が気候変動の予測に不可欠。高精度な化学分析は液相を用いる手法も多く、大気中微粒子を固体表面(例えばフィルター)に捕集し、液体へ導入させる。しかし、固体表面上に堆積したsub-micron粒子を高い効率で剥離させることが難しい課題とされてきた。




100 nm to 1 μm (sub-micron) particles are said to have the highest number concentrations of any airborne material. In order to perform detailed chemical analysis, it is often necessary to collect atmospheric particles on a filter (solid substrate) and transfer them to a liquid phase. However, it has been a difficult task to release the sub-micron particles deposited on the solid surface with high efficiency.

A protocol for the detachment of submicron (100-1000 nm) particulate samples deposited on flat substrates and their collection in aqueous samples is proposed based on a suspension-assisted ultrasonic method. As samples, combustion-made magnesium oxide (MgO) aggregates in the submicron size range were deposited in the gas phase onto three kinds of substrates: a silicon wafer and coarse and fine alumina-coated resin sheets. To enhance the sample particle detachment, a solid–liquid suspension made of candle combustion soot particles (having average sizes between 100-200 nm) was selected as an ultrasound propagation medium, which is different from the usual liquid medium, such as water, a surfactant solution, or a solvent.

Experiments were performed using low-power (42kHz and 35W) ultrasonication, and the substrates and suspensions were analyzed using scanning electron microscopy (SEM) images and particle size distributions based on dynamic light scattering (DLS), respectively.

The detachment using the medium with soot had a higher efficiency compared to that without soot, and there was an optimum soot concentration for particle detachment for all three substrates. The suspension particle size distribution after ultrasonication showed good dispersion of the sample particles in the soot suspension.

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Short Introduction of our other papers – 研究室が発表した論文の紹介 (empatlab.net)