Adsorption of Gas Phase Contaminants

Details

• Personal Author:
  Lungu CT ; Lungu CT
• Description:
  Granular activated carbon (GAC) is currently the standard adsorbent in respirators against several gases and vapors because of its efficiency, low cost and available technology. However, a drawback of GAC due to its granular form is its need for containment, adding weight and bulkiness to respirators. This makes respirators uncomfortable to wear, resulting to poor compliance in its use. Activated carbon fibers (ACF) are considered viable alternative adsorbent materials for developing thinner, light-weight and efficient respirators because of their larger surface area, lighter weight and fabric form. This study aims to determine the critical bed depth and adsorption capacity of different types of commercially available ACFs for toluene to understand how thin a respirator can be and the service life of the adsorbents, respectively. ACF in cloth (ACFC) and felt (ACFF) forms with 3 different surface areas per form were tested. Each ACF type was challenged with 6 concentrations of toluene (50, 100, 200, 300, 400, 500 ppm) at constant air temperature (23 degrees C), relative humidity (50%) and air flow (16 LPM) at different adsorbent weights and bed depths. Breakthrough data were obtained for each adsorbent using gas chromatography with flame ionization detector. The ACFs' surface areas were measured by an automatic physisorption analyzer. The results showed that ACFC has a lower critical bed depth and higher adsorption capacity compared to ACFF with similar surface area for each toluene concentration. Among the ACF types, ACFC2000 (cloth with the highest average BET surface area of 2053 +/- 6 m2/g) has one of the lowest critical bed depths (ranging from 0.11 - 0.22 cm) and has the highest adsorption capacity (ranging from 595 - 878 mg/g). It is concluded that ACF has great potential for application in respiratory protection, particularly the ACFC2000, which are the best candidates for developing thinner and efficient respirators. The Dubinin-Radushkevich (D-R) equation may successfully predict the adsorption capacities of the ACF types at lower concentrations depending on the toluene concentrations used and their corresponding experimental adsorption capacities. Using the highest two toluene challenge concentrations to predict the lower concentrations resulted to the underestimation of adsorption capacities which is attributed to the microporosity of the ACF materials, while using lower toluene challenge concentrations improved such prediction for some of the ACF types. [Description provided by NIOSH]
• Subjects:
  Occupational Health Respiratory Protective Devices Safety Toluene
• Keywords:
  Adsorbents Adsorption Equipment Design Materials Testing Respirators Respirator Testing
• Series:
  Grant Final Reports   ; Grant Final Reports  
• Publisher:
  National Institute for Occupational Safety and Health
• Document Type:
  Text
• Funding:
  Grant
• Genre:
  Final Grant Report ; Final Grant Report
• Place as Subject:
  Alabama ; OSHA Region 4
• CIO:
  National Institute for Occupational Safety and Health (NIOSH) ; National Institute for Occupational Safety and Health (NIOSH)
• Division:
  OEP - Office of Extramural Programs ; OEP - Office of Extramural Programs
• Topic:
  Workplace Safety & Health ; Workplace Safety & Health
• Location:
  North America ; North America
• Pages in Document:
  1-71
• NIOSHTIC Number:
  nn:20057453
• NTIS Accession Number:
  PB2020-100152
• Citation:
  Atlanta, GA: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, R01-OH-008080, 2011 Jan; :1-71
• Contact Point Address:
  Claudiu T. Lungu, Ph.D., University of Alabama at Birmingham, 1530 3rd Ave. South, RPHB 520B, Birmingham, AL 35294
• Email:
  clungu@uab.edu
• CAS Registry Number:
  Toluene (CAS RN 108-88-3) ; Toluene (CAS RN 108-88-3)
• Federal Fiscal Year:
  2011
• Performing Organization:
  University of Alabama at Birmingham
• Peer Reviewed:
  False
• Start Date:
  20050803
• Source Full Name:
  National Institute for Occupational Safety and Health
• End Date:
  20100731
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:e4c460897bde4ad9d475397024ffb21495c50e46149e8cd3e13b281be8d051a76087de647a0df09cd9b328c909b2954ae57df2e3218aadd41b096f6dc52b0161
• Download URL:
  https://stacks.cdc.gov/view/cdc/218934/cdc_218934_DS1.pdf
• File Type:
  [PDF - 1.99 MB ]