Fabrication of single-walled carbon nanotube (SWNT) sorbent for volatile organic compounds (VOCs) sampling

Details

• Personal Author:
  Floyd E ; Lungu CT ; Oh, Je M.
• Description:
  Introduction: To investigate and compare fabrication methods of single walled carbon nanotube (SWNT) buckypapers by quantifying adsorption efficiencies. A new desorption technique is PhotoThermal Desorption (PTD) which is: a) visible light (photo flash) thermally desorbing an analyte & quantified by photoionization detector; and b) an alternative for VOCs analysis of passive sampler. The PTD technique can: c) eliminate sample preparation time and cost; and d) bridge the sensitivity gap between chemical desorption and thermal desorption. Purpose: To develop a carbon nanotube (CNT) sorbent coupled with photothermal desorption technique to be used in a VOC passive sampler. 1. Investigate fabrication methods of SWNTs to a self-standing form (i.e., buckypaper). 2. Examine adsorption efficiencies (i.e., surface area, pore size, and toluene adsorption isotherm). Methods: Arc discharge SWNT solution was fabricated into a buckypaper with or without a cleaning process. SWNT solution was suspended in solvents/surfactants. The solution was vacuum filtered and additionally cleaned with deionized water and solvents. Three types of buckypaper (BP) samples (50 mg each, n=2); acetone (with and without cleaning) and methanol (with cleaning). Buckypapers produced were analyzed (physisorption analyzer determines the capacity and affinity of the adsorbents to VOCs) for adsorption efficiency by toluene adsorption isotherm and surface area, and pore size measurements with nitrogen and toluene as an adsorbates. Results: Adsorption efficiency, surface area and pore size of arc discharge of BP - Fabrication Method - Surface Area (m2/g)3 - NOT-CLEANED BP (Acetone suspension & Filtration w/o Cleaning) is 45 +/- 2; ACETONE-CLEANED BP (Acetone suspension & Filtration with Cleaning) is 217 +/- 27 (349 +/- 10); METHANOL- CLEANED BP (Methanol suspension & Filtration with Cleaning) 348 +/- 13 (421+/- 6). Fabrication Method - Pore Size (nm) - NOT-CLEANED BP (Acetone suspension & Filtration w/o Cleaning) is 14.9 +/- 0.0; ACETONE-CLEANED BP (Acetone suspension & Filtration with Cleaning) is 9.1+/- 0.4 (9.8 +/- 0.1); METHANOL- CLEANED BP (Methanol suspension & Filtration with Cleaning) 8.0 +/- 0.1(8.6 +/- 0.1). Adsorption efficiency for Toluene Adsorption Isotherm were acetone-cleaned BP (150 cm3/g STP) and methanol-cleaned BP (187 cm3/g STP). Acetone-Cleaned BP is 618, and Methanol-Cleaned BP is 770. Conclusions/Future Work: 1. Cleaning process was necessary for this material (i.e., arc discharge SWNT solution) and methanol cleaning fabrication method was the most efficient. 2. Toluene adsorption capacity was proportional to surface area. 3. Increase surface area by fabrication (e.g., annealing). 4. Examine other types of sorbents [e.g., HiPco (high pressure CO) SWNTs, carbonaceous particles, etc.]. 5. Test PhotoThermal Desorption (PTD) efficiency of the samples. 6. Build a passive sampler unit for photothermal desorption. [Description provided by NIOSH]
• Subjects:
  Acetone Dust Environmental Monitoring Filtration Manufacturing And Industrial Facilities Metals Nitrogen Compounds Occupational Health Safety Surface-Active Agents
• Keywords:
  Acetones Adsorbents Air-sampling Air-sampling-equipment Carbon-compounds Chemical-cleaning Cleaning-compounds Filter-fabrics Filter-membranes Filters Materials-testing Metal-dusts Nanotechnology Nitrogen-compounds Organic-chemicals Organic-compounds Performance-capability Porous-materials Samplers Sampling-equipment Structural-analysis Surface-properties Surfactants Vacuum-equipment Volatiles

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• Publisher:
  World Health Organization
• Document Type:
  Text
• Funding:
  Grant
• Genre:
  Proceedings
• Place as Subject:
  Alabama ; Oklahoma ; OSHA Region 4 ; OSHA Region 6
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  1-13
• NIOSHTIC Number:
  nn:20047845
• Citation:
  IOHA 2015. 10th International Scientific Conference of the International Occupational Hygiene Association, April 25-30, 2015, London, United Kingdom. Geneva, Switzerland: World Health Organization, 2015 Apr; :1-13
• CAS Registry Number:
  Acetone (CAS RN 67-64-1) ; Carbon (CAS RN 7440-44-0)
• Federal Fiscal Year:
  2015
• Performing Organization:
  University of Alabama at Birmingham
• Peer Reviewed:
  False
• Start Date:
  20130901
• Source Full Name:
  IOHA 2015. 10th International Scientific Conference of the International Occupational Hygiene Association, April 25-30, 2015, London, United Kingdom
• End Date:
  20150831
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:7fbbbe47f07c7f3b2a96ce60feb344553d02f0b0ef356716e28eaccd326cb6233bfc4241a0b3a3881ae11d22ec5acff9c14df4e6ae8e6e10d3d3d20dced48ea3
• Download URL:
  https://stacks.cdc.gov/view/cdc/202805/cdc_202805_DS1.pdf
• File Type:
  [PDF - 952.56 KB ]