Sodium hydroxide(NaOH) is one of the chemicals produced great quantity in Korea. It variously uses for acid neutralization, petroleum refining, electroplating, metal cleaning, laundering, bleaching, washing dish, manufacture of paper, etc. NaOH is used in various field of industry but information on the sampling efficiency for NaOH IS seldom provided. The objective of this study was to compare the sampling efficiency of the three-piece cassette sampler with the modified two-piece cassette sampler.
The three-pieces cassette consisted of an inlet cover, a spacer, a mixed cellulose ester membrane(MCE) filter, a back-up pad and a bottom. The modified two-pieces cassette consisted of the same parts as a three-piece cassette without a spacer. The whole inner surface of the 2-piece cassette was loaded with MCE filter to ensure that all of the aspirated NaOH. The air sampling of airborne NaOH WAS performed according to the Occupational Safety and Health Administration(OSHA) analytical method manual ID-121 that is used for the method of occupational environment measurement and analysis. Air samplings were per-formed by simultaneous samplings using the three-piece and modified two-piece cassette sampler at the same time and same place in the chemical plants.
The significant difference between average adsorbed amounts on the MCE filters of the three-piece and modified two-piece cassette sampler was found. Sampling amounts of the modified two-piece cassette sampler was 1.84 times higher than that of the three-piece casstte sampler(p＜0.01). An average 47% of NaOH was collected on the upper (inlet+middle-rim) side of the modified two-piece cassette. As the result of his study, it is verified that the modified two-piece cassette sampler is more effective than the three-piece cassette sampler for collection of airborne NaOH.
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