奈米碳管電暈放電裝置與應用

Carbon nanotubes based corona discharge apparatus and its application

黃富盛(Fu-Sheng Huang)

指導教授 ： 黃榮堂

國立臺北科技大學/機電學院/機電整合研究所/碩士(2005年)

摘要

本研究主要在發展一創新的奈米碳管(carbon nanotubes)電暈放電裝置，探討其對於空氣中之奈米懸浮粉塵與微生物粒子的充電能力與收集效率，製作出一套有效低成本而輕便的個人攜帶化空氣品質狀態偵測器。
傳統使用的電暈Corona充電裝置設備，其電極上多採用針狀金屬以陣列方式排列來作為放電機制，不僅製作困難，並因為兩電極板之間的間距大，所以須要高電壓來達到所需的電場，且所佔的空間大，也不容易攜帶。發展一種可於低電壓操作的小型電暈(corona)放電裝置，係由兩層至多層奈米碳管陣列所形成的基板所構成，層與層之間以隔間器(spacer)維持一間隔，各層之間隔約為500μm-1000μm之間，可依施加的交流電壓而定，較佳的電壓為500V-1000V，基板為導電性材料或具導電層，利用真空邦浦(vacuum pump)抽氣，空氣中的微小粒子伴隨著空氣通過多層奈米碳管陣列所形成的基板之間，因施加的電壓在奈米碳管的尖端放電，而產生電荷，並附著於空氣中的微小粒子而達成充電的功效，並可因此利於後續的靜電收集於水中。
測試生物氣膠選用酵母菌、大腸桿菌與枯草桿菌三種微粒測試。實驗結果顯示在量測氣膠微粒在1μm以上充電量1000V時所測得收集效率為95%以上。在沒有充電下，收集效率低於20%。需在持續改善奈米碳管的塗佈，提升放電電流，使得收集效率提升。

關鍵字

生物氣膠 ； 電暈放電 ； 奈米碳管 ； 氣膠取樣器

並列摘要

The main focus of this proposal is to develop novel carbon nanotubes based corona discharge equipment. And then evaluate its capability of discharging electrons on the micro/nano-particles or airborne microorganisms. We expect to design an atmospheric quality detecting equipment which could become a personal portable product after this study.

Most of the traditional corona discharge equipments have plates with needles spread on it by means of matrix distribution as a discharge function. But this needles geometry is difficult to build, and the distance of these two plates is so wide that we must reinforce the magnitude of voltage to achieve the required high electric field. Besides, the large volume may cause it to carry inconveniently. In our research, we developed a small corona discharge apparatus, which could operate under low voltage. The said apparatus composed of two or more substrates deposited with matrix of carbon nanotubes. There is a spacer between any two substrates with gap about 500um to 1000um, the gap distance depended on the voltage which we applied to the substrates, and moreover, the preferred voltage which we applied is 500V to 1000V. Carbon nanotubes are 10nm length and the diameter about 10nm to 20nm. The substrates are conductive materials or coated with conductive materials. By using a vacuum pump, the airflow can pass through the said apparatus. When the mirco-particle in the air followed by airflow pass through the substrates, the electric charge produced due to the corona discharge on the carbon nanotubes can attach to the mirco-particles to achieve the charging effect.

Test particles such as Yeast, E.coli, and Subtilis were chosen. Experimental results indicate that the apparatus has the collection efficiency >95 % for particles >1μm at charging voltage of 1000V. The apparatus without charging has the collection efficiency <20%. It is expected if we improve the distribution and characteristics of carbon nanotubes sprayed on the substrate we can get higher discharge current and collection efficiency.

並列關鍵字

Bioaerosols ； Corona discharge ； Carbon nanotube ； Aerosol sampler

參考文獻

[1] Sumio Iijima, "Helical microtubules of graphitic carbon," Nature, vol. 354, 1991, pp. 56-58.

[6] R.C. Davison, D.F.S. Natusch, J.R Wallace and C.A.Jr Evans, "Trace Elements in FlyAsh-Dependence of Concentration on Particle Size," Environment Science Technology, vol. 8, 1974, pp. 1107-1113.

Sergey A. Grinshpun, "Development and evaluation of a new personal sampler

[10] Gediminsa Mainelis, Atin Adhikari, Klaus Willeke, Tiina Peponen and Sergey A. Grinshpun, "Collection of airborne microorganisms by a new electrostatic precipitator," Journal of Aerosol Science, vol. 33, 2002, pp. 1417-1432.

[11] Hung Min Chein, Yu-Du Hsu, Tzu Ming Chen and Chuen Jinn Tsai, "An Axial