活性碳纖維濾材過濾效能及添加營養源對細菌存活率探討

The Study of Filter Quality and Surviving of Bacteria on Activated Carbon Fiber Filter

陳孟偉(Meng-Wei Chen)

指導教授 ： 賴全裕

中山醫學大學/健康管理學院/職業安全衛生學系碩士班/碩士(2012年)

摘要

當SARS和H1N1等疾病盛行時，會佩戴活性碳口罩來防止吸入有害病源體。然而，活性碳口罩是設計用來吸附氣態污染物，無法有效的過濾氣膠。並且活性碳可能可以提供細菌更好的生存空間，將間接對人體造成傷害。活性碳纖維的比表面積較活性碳大，吸附效率較高。因此若以活性碳纖維布權充口罩材質時，其過濾效率及細菌負載現象則是值得進行的研究嘗試。

本研究將建置測試系統，選擇酒石酸鉀鈉（Potassium Sodium Tartrate Tetrahydrate, PST）作為挑戰氣懸微粒。以氣動粒徑微粒偵測器（Aerodynamic Particle Sizer, APS）及微粒電移動度掃瞄分徑器（Scanning Mobility Particle Sizer, SMPS）進行氣膠數目、粒徑分佈之測試，以注射式幫浦（Syringe Pump）、超音波霧化噴嘴（Ultrasonic Atomizing Nozzle）產生次微米粒徑挑戰氣膠，以定量輸出霧化器（Constant Output Atomizer）產生微米粒徑之挑戰氣膠，以Kr-85及Am-241中和挑戰氣膠至波茲曼分佈，研究比較兩種活性碳纖維濾布、兩種活性碳纖維氈與單種SMS（Spunbond+ Meltblown+ Spunbond）不織布在不同粒徑下之貫穿率；並且測量其在不同流率下之壓損，來模擬不同呼吸程度下濾材之通氣阻抗，實驗並以各粒徑之貫穿率與通氣阻抗計算其過濾品質（Filter Quality, qf），藉以探討以活性碳纖維濾材作為口罩濾材時之效能。
研究滴加含有枯草桿菌內孢子，比較未添加及添加人工唾液、無菌水和人工汗液，並放入恆溫恆濕培養箱分別置放1天、2天、4天和8天之存活率；使用XRF（X-ray fluorescence analysis, XRF, X-ray SII SEA 2220A）及高解析感應耦合電漿質譜儀（Inductively Coupled Plasma-Mass Spectrometer, ICP-MS）分析樣本及樣本浸泡於營養源1天後所溶出元素；本研究亦以統計的方式探討不同元素、營養源及樣本對於細菌存活率之相關性，以探討活性碳濾材之營養源及回潮率與含水率對細菌存活率的影響。

研究結果顯示：在濾材效率測試方面，隨著選取樣本的厚度增加，造成樣本通氣阻抗的增加，但各粒徑之微粒貫穿率降低；而過濾效能之改變與通氣阻抗與各粒徑之微粒貫穿率有關，活性碳纖維布及活性碳纖維氈之過濾品質皆高於SMS不織布；但研究結果發現，貫穿率最低的樣本（四層濾布）於最易穿透粒徑之貫穿率高達29.8 %，並且在枯草桿菌長度及寬度範圍中，最好的濾材仍有最高10.20 %之穿透率，顯示若要以本研究所採用之活性碳纖維濾材做為口罩濾材，仍需降低其微粒貫穿率為首要。

而細菌負載的研究結果表示，營養源的添加及溶出的矽元素與鋅元素，對於枯草桿菌負載細菌後之存活率有顯著的影響，而枯草桿菌存活率在第二天後為最高，其存活率可達150 %，顯示若以活性碳纖維濾材作為口罩之過濾濾材，當使用者重複使用口罩時，有可能會增加使用者受到細菌感染之風險。

綜合以上結果，若要以活性碳纖維濾材做為口罩之濾材，必須先降低其濾材貫穿率，並且避免重複使用口罩。

關鍵字

活性碳纖維 ； 濾材 ； 貫穿率 ； 營養源 ； 存活率

並列摘要

When the severe acute respiratory syndrome（SARS）or Hemagglutinin 1 Neuraminidase 1（H1N1）virus attacked human beings all over the world, some people in Taiwan wore activated carbon mask to prevent inhalation of hazardous bioaerosols. However, activated carbon mask is designed to adsorb gaseous contaminates, but not to use for filtrating of aerosols. The activated charcoal may provide better space for the survival of bacteria, and indirectly hurt human body for reentrainment of bacteria. However, activated carbon fabric（ACF）and activated carbon felt are excellent adsorbent materials with a large surface area. It will be a trier to use them for the filter material and test them for the loading effect of bacteria.

In the study, a Syringe Pump, ultrasonic atomizing nozzle and Constant Output Atomizer was used to generate Potassium Sodium Tartrate Tetrahydrate as challenge aerosol particles. Two Activated carbon fabric samples, two Activated carbon felt samples and one SMS（Spunbond+ Meltblown+ Spunbond）nonwoven were recruited in the study as the filter samples. Two radioactive sources, Am-241 and Kr-85 were used to neutralize the challenge particles to the Boltzmann charge equilibrium. An Aerodynamic Particle Sizer（APS）and Scanning Mobility Particle Sizer（SMPS）were used to measure the number and size distributions of the challenge particle to consider the penetration of different filter samples. The pressure drops of different ACF of different flow rate were measured to simulate the pressure drop in different depth of respiration. Filter quality was calculated by particle penetration and pressure drops. Dripped liquid containing Bacillus subtilis spores on sample, and compared the survival rate of the bacteria between the control group（without nutrient）, artificial saliva group, sterile water group and artificial perspiration group, after they had been placed in constant temperature and humidity incubators for 1 day, 2 days, 4 days and 8 days. X-ray fluorescence（XRF, X-ray SII SEA 2220A）and Inductively Coupled Plasma-Mass Spectrometer（ICP-MS）were used to analyze metal elements from filter samples and elution of filter one-day-soaking of nutrients.

The results showed that when the thickness of filter samples increased, the pressure drops of different Activated carbon fabric and Activated carbon felt were increased, but the penetration of filter samples were decrease. Changing of filter samples pressure drop and particle penetration can change the filter quality of filter samples. The filter quality of two Activated carbon fabric samples and two Activated carbon felt samples were higher than SMS nonwoven. However, the particle penetrations were higher than usual masks. Even 4-layer C and E filters were used, the penetrations in most penetrating sizes of the two filters were still higher than 29.8 %. On the other hand, the results of bacteria loading revealed that the elution of Si and Al from the filter one-day-soaking of nutrients could survive Bacillus subtilis to 150 %. Those above results might increase the potential hazards of bacteria infection.

並列關鍵字

activated carbon fiber ； filter quality ； penetration ； nutrient ； survival rate

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