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J Air Waste Manag Assoc

Title:		Breakthrough indicator for aromatic VOCs using needle trap samplers for activated carbon adsorbent
Author(s):		Cheng WH; Jiang JR; Huang YN; Huang SC; Yu YP;
Address:		"Department of Occupational Safety and Hygiene, Fooyin University, Kaohsiung City, Taiwan. pl031@mail.fy.edu.tw"
Journal Title:		J Air Waste Manag Assoc
Year:		2012
Volume:		62
Issue:		8
Page Number:		946 - 952
DOI:		10.1080/10962247.2012.693056
ISSN/ISBN:		1096-2247 (Print) 1096-2247 (Linking)
Abstract:		"Internal circulation cabinets equipped with granular activated carbon (GAC) for adsorbing volatile organic compounds (VOCs) are widely used to store bottles containing organic solvents in universities, colleges, and hospital laboratories throughout Taiwan. This work evaluates the VOC adsorption capacities of GAC using various adsorption times for gas stream mixtures of 100 ppm toluene and 100 ppm o-xylene. Additionally, needle trap sampling (NTS) technology was used to indicate the time for renewing the GAC to avoid VOC breakthrough from adsorbents. Experimental results demonstrate that the proposed models can linearly express toluene and o-xylene adsorption capacities as the natural logarithm of adsorption time (ln(t)) and can accurately simulate the equilibrium adsorption capacities (Qe, g VOCs/g GAC) for gaseous toluene and o-xylene. The NTS, packed with 60-80 mesh divinylbenzene (DVB) particles, was compared in terms of extraction efficiency by simultaneously using the 75-microm Carboxen/polydimethylsiloxane-solid-phase microextraction (Carboxen/PDMS-SPME) fiber for time-weighted average (TWA) sampling, and experimental results indicated that the packed DVB-NTS achieved higher toluene extraction rates. Additionally, the NTS installed in the outlet air stream for adsorbing toluene and o-xylene exhausted through GAC accurately indicated toluene and o-xylene breakthrough times of 4700-5000 min. The GAC-NTS operational instructions to indicate the replacing time of adsorbent in the internal circulation cabinets are also included in this paper"
Keywords:		Adsorption Carbon/*chemistry Environmental Monitoring/economics/*instrumentation/methods Volatile Organic Compounds/*chemistry;
Notes:		"MedlineCheng, Wen-Hsi Jiang, Jia-Rong Huang, Yi-Ning Huang, Shiun-Chian Yu, Yan-Pin eng Research Support, Non-U.S. Gov't 2012/08/25 J Air Waste Manag Assoc. 2012 Aug; 62(8):946-52. doi: 10.1080/10962247.2012.693056"