尼龍濾紙對鹽酸及硝酸氣體的吸附研究

Abstract

本研究的目的為釐清圓環型固氣分離採樣器濾紙組部分所使用的尼龍濾紙（Nylasorb membrance，47 mm diameter， 1.0μm pore size，Gelman Laboratory，USA）是否具有足夠的吸附容量來吸附由鐵氟龍濾紙上微粒揮發的鹽酸及硝酸氣體，研究內容可區分為尼龍濾紙於不同相對濕度下對鹽酸及硝酸氣體的吸附容量實驗、混和干擾實驗與戶外採樣比較。 在尼龍濾紙對鹽酸及硝酸氣體的吸附容量實驗部分，結果顯示，當實驗系統的溫度為30 ± 2 ℃，相對濕度分別為20 ± 5 ％、55 ± 5 ％ 及80 ± 5 ％的操作條件下，尼龍濾紙對鹽酸氣體的吸附容量分別約8μg、160μg及240μg，對硝酸氣體的吸附容量分別約160μg、1400μg及1900μg。 在尼龍濾紙對硝酸及鹽酸氣體的混和干擾實驗部分，研究發現，尼龍濾紙在有硝酸氣體的干擾下，會導致其對鹽酸氣體的吸附效率降低，尤其在濕度小於25 ％的情況下，干擾現象更是顯著，吸附效率最低降至35 ％；而尼龍濾紙在有鹽酸氣體的干擾下，卻對硝酸氣體的吸附效率沒有明顯的干擾問題，吸附效率最低降至95 ％。 在戶外採樣部分，利用圓環型固氣分離採樣器及蜂巢式套管採樣器進行採集比較，並於各採樣器的濾紙組部分裝置了四階濾紙，其中第二、三階皆放置尼龍濾紙，以瞭解尼龍濾紙是否有吸附容量不足的問題。結果顯示，濾紙組部分只需放置一張尼龍濾紙就可以完全吸附由鐵氟龍濾紙上微粒揮發的鹽酸及硝酸氣體。 由本研究於實驗室與戶外採樣的實驗結果可知，尼龍濾紙（Nylasorb membrance，47 mm diameter， 1.0μm pore size，Gelman Laboratory，USA）在一般的大氣條件（濕度介於40∼90 ％）及採集條件（採集流量為10 L/Min，採集時間為24小時）下，是具有足夠的吸附容量來吸附由鐵氟龍濾紙上微粒揮發的鹽酸及硝酸氣體。

The Objective of this study is to know the nylon filter (Nylasorb membrance, 47 mm diameter, 1.0μm pore size, Gelman Laboratory, USA) of annular denuder system whether it has enough capacity to adsorb HCl and HNO3 gases evaporated from the particles on the teflon filter. The contents include the collection capacity test of nylon filter to adsorb HCl 、 HNO3 gases, the interfered test of nylon filter to adsorb HCl and HNO3 gases and ambient sampling comparison . In the collection capacity test of nylon filter, the testing temperature is 30 ± 2 ℃ and the relative humidity are 20 ± 5 ％、55 ± 5 ％ and 80 ± 5 ％, respectively. Under the testing condition, the data indicates the capacity of nylon filter to adsorb HCl gas is 8μg、160μg、240μg and HNO3 gas is 160μg、1400μg 、1900μg, respectively. In the interfered test of nylon filter, the data indicates the collection efficiency of nylon filter to adsorb HCl gas will be interfered evidently when HNO3 is added ,and the collection efficiency is declined to as little as 35 % while the testing relative humidity is 20 ± 5 ％; however , there is no significant effect for nylon filter to adsorb HNO3 when HCl exists, the collection efficiency is greater than 95 %. In the ambient sampling, the Annular Denuder System and Honeycomb Denuder Sampler are used and four-stage filters are arranged in each filter pack , the second and third stage are nylon filters. The data indicates HCl and HNO3 gases evaporated from the particles on the teflon filter can be collected completely by only one stage of nylon filter. To sum up, under the ambient condition ( relative humidity : 40-90 %) and sampling condition ( sampling flowrate : 10 L/Min, sampling time : 24 hrs), the nylon filter (Nylasorb membrance, 47 mm diameter, 1.0μm pore size, Gelman Laboratory, USA) of annular denuder system has enough capacity to adsorb HCl and HNO3 gases evaporated from the particles on the teflon filter.