title: A new desorption method for removing organic solvents from activated carbon using surfactant.
abstract: OBJECTIVE
  A new desorption method was investigated, which does not require toxic organic solvents. Efficient desorption of organic solvents from activated carbon was achieved with an ananionic surfactant solution, focusing on its washing and emulsion action.
  
  
  METHODS
  Isopropyl alcohol (IPA) and methyl ethyl ketone (MEK) were used as test solvents. Lauryl benzene sulfonic acid sodium salt (LAS) and sodium dodecyl sulfate (SDS) were used as the surfactant. Activated carbon (100 mg) was placed in a vial and a predetermined amount of organic solvent was added. After leaving for about 24 h, a predetermined amount of the surfactant solution was added. After leaving for another 72 h, the vial was heated in an incubator at 60°C for a predetermined time. The organic vapor concentration was then determined with a frame ionization detector (FID)-gas chromatograph and the desorption efficiency was calculated.
  
  
  RESULTS
  A high desorption efficiency was obtained with a 10% surfactant solution (LAS 8%, SDS 2%), 5 ml desorption solution, 60°C desorption temperature, and desorption time of over 24 h, and the desorption efficiency was 72% for IPA and 9% for MEK. Under identical conditions, the desorption efficiencies for another five organic solvents were investigated, which were 36%, 3%, 32%, 2%, and 3% for acetone, ethyl acetate, dichloromethane, toluene, and m-xylene, respectively.
  
  
  CONCLUSIONS
  A combination of two anionic surfactants exhibited a relatively high desorption efficiency for IPA. For toluene, the desorption efficiency was low due to poor detergency and emulsification power.
authors.affiliation: Department of Environmental Management, School of Health Sciences, University of Occupational and Environmental Health, Japan.
authors.forename: Mitsuo
authors.initials: M
authors.lastname: Hinoue
authors.forename: Sumiyo
authors.initials: S
authors.lastname: Ishimatsu
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Fueta
authors.forename: Hajime
authors.initials: H
authors.lastname: Hori
mesh_terms: D019840:2-Propanol / Q000032:analysis* / Q000737:chemistry; D002074:Butanones / Q000032:analysis* / Q000737:chemistry; D002623:Chemistry Techniques, Analytical; D002849:Chromatography, Gas; D004784:Environmental Monitoring / Q000379:methods; D009930:Organic Chemicals / Q000032:analysis / Q000737:chemistry; D012967:Sodium Dodecyl Sulfate / Q000008:administration & dosage*; D012997:Solvents / Q000032:analysis; D013451:Sulfonic Acids / Q000008:administration & dosage*; D013501:Surface-Active Agents / Q000008:administration & dosage; D014050:Toluene / Q000032:analysis / Q000737:chemistry
chemical_list: D002074:Butanones; D009930:Organic Chemicals; D012997:Solvents; D013451:Sulfonic Acids; D013501:Surface-Active Agents; D012967:Sodium Dodecyl Sulfate; D014050:Toluene; C005222:methylethyl ketone; D019840:2-Propanol