All ETDs from UAB

Advisory Committee Chair

Claudiu T Lungu

Advisory Committee Members

Alfred A Bartolucci

Robert W Peters

Edward M Postlethwait

Giuseppe L Squadrito

Document Type

Dissertation

Date of Award

2011

Degree Name by School

Doctor of Philosophy (PhD) School of Public Health

Abstract

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 fiber (ACF) is considered a viable alternative adsorbent material 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 °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 can 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.

Included in

Public Health Commons

Share

COinS