title: Removal of arsenate and 17alpha-ethinyl estradiol (EE2) by iron (hydr)oxide modified activated carbon fibers.
abstract: Activated carbon fibers (ACF) were modified with iron (hydr)oxide and studied to determine their suitability to remove arsenate and 17alpha -ethinyl estradiol (EE2) from water. Two synthesis methods, one involving aqueous KMnO(4) pretreatment followed by Fe(II) treatment, and the other involving reaction with Fe(III) in an organic solvent followed by NaOH treatment, were used to produce modified ACF media containing 5.9% and 8.4% iron by dry weight, respectively. Scanning electron microscopy (SEM) and Electron dispersion X-ray (EDX) techniques indicated slightly higher iron content near the outer edges of the fibers. Pseudo-equilibrium batch test experimental data at pH = 7.0 +/- 0.1 in 5 mM NaHCO(3) buffered ultrapure water containing approximately 100 micro g(As)/L and approximately 500 micro gEE2/L were fitted with the Freundlich isotherm model (q = K x C(E)(1/n)). The adsorption capacity parameters (K) were approximately 2586 (micro gAs/gFe)(L/micro gAs)(1/n) and approximately 425 (micro gAs/gFe)(L/micro gAs)(1/n)), respectively, for the KMnO(4)/Fe(II) and Fe(III)/NaOH treated media. The KMnO(4)/Fe(II) media exhibited a lower adsorption capacity at 99% EE2 removal than did the Fe(III)/NaOH treated media (1.3 mgEE2/g -dry -media vs. 1.8 mgEE2/g -dry -media). The arsenate adsorption intensity parameters (1/n) for both modified ACF media were < 0.29, implying very favorable adsorption, which suggests that this type of media may be suitable for single point -of -use applications in which arsenic and organic co-contaminants require simultaneous removal and the depth of the packed bed is the key factor.
authors.affiliation: Department of Civil and Environmental Engineering, Arizona State University, Tempe, Arizona 85287-5306, USA. kiril.hristovski@asu.edu
authors.forename: Kiril D
authors.initials: KD
authors.lastname: Hristovski
authors.forename: Hanhphuc
authors.initials: H
authors.lastname: Nguyen
authors.forename: Paul K
authors.initials: PK
authors.lastname: Westerhoff
mesh_terms: D000327:Adsorption; D001149:Arsenates / Q000302:isolation & purification*; D002244:Carbon / Q000737:chemistry*; D004997:Ethinyl Estradiol / Q000302:isolation & purification*; D005290:Ferric Compounds / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning
chemical_list: D001149:Arsenates; D005290:Ferric Compounds; C000499:ferric oxide; D004997:Ethinyl Estradiol; D002244:Carbon; C025657:arsenic acid