slide1 n.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
Evaluation of Activated Carbon Fibers for Removal of Volatile Organic Compounds in Indoor Environments PowerPoint Presentation
Download Presentation
Evaluation of Activated Carbon Fibers for Removal of Volatile Organic Compounds in Indoor Environments

Loading in 2 Seconds...

play fullscreen
1 / 27

Evaluation of Activated Carbon Fibers for Removal of Volatile Organic Compounds in Indoor Environments - PowerPoint PPT Presentation


  • 150 Views
  • Uploaded on

Evaluation of Activated Carbon Fibers for Removal of Volatile Organic Compounds in Indoor Environments. Huajun Lu Neil Zimmerman PhD CIH Purdue University School of Health Sciences Oct., 17 th , 2003. OVERVIEW. Introduction of Indoor air quality (IAQ) Purposes of Study

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Evaluation of Activated Carbon Fibers for Removal of Volatile Organic Compounds in Indoor Environments' - Thomas


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
slide1

Evaluation of Activated Carbon Fibers for Removal of Volatile Organic Compounds in Indoor Environments

Huajun Lu

Neil Zimmerman PhD CIH

Purdue University

School of Health Sciences

Oct., 17th, 2003

overview
OVERVIEW
  • Introduction of Indoor air quality (IAQ)
  • Purposes of Study
  • Materials and Methods
  • Theoretical Background
  • Results
  • Conclusions
iaq background
IAQ Background
  • In developing countries, use of biomass fuels for cooking and heating
      • Result in 2 million death annually.
      • Associated with adverse pregnancies
      • Increase the risk of young child’s serious respiratory infection
  • One-half of U.S schools have problems linked to indoor air quality problems
  • Ranks among top five environmental risks to public health
  • Lost productivity estimated $60 billion per year
sources of concern for iaq
Sources of Concern for IAQ
  • Inadequate ventilation
  • Hazardous gases such as CO, NOx, etc.
  • Formaldehyde
  • Respirable particles
  • Pesticides
  • Biological contaminants
        • Bacteria
        • Mold
        • Viruses
        • Pollen
  • Volatile organic compounds (VOCs)
adsorption
Adsorption
  • Adsorption is the process of trapping gas and vapor molecules within the pores of a microporous solid such as activated carbon.
  • Influence factors
      • Surface interactions between adsorbate and adsorbent
      • Surface area of adsorbate
      • Pore size of adsorbate
  • Adsorption media
      • Alumina / potassium permanganate
      • Zeolite (molecular sieve)
      • Granular activated carbon (GAC)
      • Activated carbon fiber (ACF)
why acf
Why ACF?
  • Compared to GAC, ACF has the following advantages:
      • Greatly improved contact efficiency with adsorbates leading to greater rates of adsorption,
      • Superior breakthrough capacity and excellent adsorption properties to low concentration of contaminants (Yue, et al., 2001).
      • Availability of felt or fabric forms: occupying smaller space
      • Electrical reactivation: saving reactivation cost (Suzuki, 1994, Economy and Lin, 1976).
what does the fiber look like
What Does the Fiber Look Like?

Typical SEM micrograph of ACF-15

Dia.=16 m

Reference: Foster, K.L., Doctoral dissertation, UIUC, IL, 1993

typical surface image of single fiber
Typical Surface Image of Single Fiber

Reference: Foster, K.L., Doctoral dissertation, UIUC, IL, 1993

typical cross section image of single fiber
Typical Cross-section Image of Single Fiber

Reference: Foster, K.L., Doctoral dissertation, UIUC, IL, 1993

purposes of study
Purposes of Study
  • To determine adsorption and desorption parameters for selected VOCs on ACF and typical indoor materials;
  • To establish an IAQ model based on the sink effects of indoor materials and adsorption by ACF
chamber diagram
Chamber Diagram

Injection port

Fan

Incoming air

Outgoing air

test materials
Test Materials
  • Test Materials:
      • Cotton: 100% cotton cloth
      • Carpet:
      • Polyester
      • Wallboard: Gold Bond® regular gypsum board with 100% paper in both sides, 12.7mm in thickness
      • ACF Surface area (m2/g)
        • ACF-10 738
        • ACF-15 1390
        • ACF-20 1600

Reference: Foster, K.L., et al., Chem.Mater., 4: 1068-1073, 1992

Mangun, C.L., et al., Chem. Mater. 11, 3476-3483, 1999

sampling strategies
Sampling Strategies
  • Sampling and analysis of samples
      • Sampling intervals vary from 3 minutes to 3 hours
      • Sampling time ranges from 1 minutes to 10 minutes
      • Sampling flowrate: 80 ml/min
      • Active sampling with activated coconut charcoal tubes
      • CS2 as desorber
      • Gas chromatography/Flame ionizing detector
model development
Model Development

Chamber interior surfaces

Adsorption materials

iaq model
IAQ Model
  • For empty chamber:

With initial conditions: C0=Ce, M0=Me

  • For chamber with ACF or indoor materials:

Initial values: t=0, C0=0, M1=0, M2=0

equations for prediction of adsorption capacity
Equations for Prediction of Adsorption Capacity
  • Freundlich isotherm equation:

Where: m ----- The mass of adsorbate adsorbed per unit adsorbent, mg/g

C ----- Concentration in bulk gas phase

K, n --- Empirical constants

  • Dubinin-Radushkevichequation:

Where: V----Volume of the adsorbate adsorbed at temperature T, cm3/g

V0---- Total active volume of ACF, cm3/g

A---- RT*ln(P0/P), adsorption potential, J/mol, P0, saturation vapor

pressure, P, partial pressure of adsorbate at equilibrium

β ---- Affinity coefficient, with respect to benzene in this project

E0----Characteristic adsorption energy

freundlich isotherm parameters
Freundlich Isotherm Parameters

Freundlich Equation after log-transformation

conclusions
Conclusions
  • For ACF static adsorption of toluene, the correlation coefficients for the experimental data were >0.97 based on both Freundlich and Dubinin-Radushkevich equations.
  • For ACF static adsorption, the adsorption capacity correlates with surface area, and pore size distribution.
  • Among tested indoor building materials, carpet has the greatest adsorption capacity for toluene.
  • Qualitatively speaking, ACF has significantly greater adsorption capacity than indoor building materials, thus, making it possible to aid removal of VOCs in passive mode.
acknowledgements
Acknowledgements
  • Committee members:
      • Dr. Neil Zimmerman
      • Dr. Gary Carlson
      • Dr. Herman Cember
      • Dr. Yan Chen
  • Dr. George Sandison
  • Dr. Frank Rosenthal
  • Mr. Xinzhu Pu
  • Dr. Zhishi Guo (EPA, Research triangle park)
  • Dr. Jianshun Zhang (Syracuse University)
  • Mr. Miao Yang (Syracuse University)
  • This research study was (partially) supported by the NIOSH Pilot Project Research Training Program of the University of Cincinnati Education and Research Center Grant #T42/CCT510420.