title: Arsenic removal from water using iron-impregnated granular activated carbon in the presence of bacteria.
abstract: This study investigated the adsorption of arsenite [As(III)] and arsenate [As(V)] to iron-impregnated granular activated carbon (Fe-GAC), focusing on the effects of bacteria on arsenic removal. Characteristics of Fe-GAC were analyzed using field emission scanning electron microscopy along with energy dispersive X-ray spectrometry. Batch experiments were performed under various experimental conditions to determine the adsorption of As(III) and As(V) to Fe-GAC in the absence and presence of bacteria (Enterococcus faecalis, Escherichia coli, or Bacillus subtilis). In addition, biosorption of As(III) and As(V) to bacteria was observed with batch experiments. Experimental results showed that Fe-GAC was characterized by mosaic-like deposition layers separated by interspacing on the surface. Iron impregnation increased the removal of As(III) and As(V) in GAC. Biosorption experiments indicated that a small amount of As(V) adsorbed to bacteria while no adsorption of As(III) was observed. This phenomenon can be attributed to interactions of anionic As(V) with positively-charged amine groups present on bacterial surfaces. Results also showed that the influence of bacteria on arsenic removal in Fe-GAC was not eminent in our experimental conditions even though bacteria could occupy surface adsorption sites on iron (hydr)oxides. This study demonstrated that hindrance effects of bacteria on arsenic adsorption to the surfaces of Fe-GAC were minimal.
authors.affiliation: Environmental Biocolloid Engineering Laboratory, Department of Rural Systems Engineering/Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul, Korea.
authors.forename: Hyon-Chong
authors.initials: HC
authors.lastname: Kim
authors.forename: Chang-Gu
authors.initials: CG
authors.lastname: Lee
authors.forename: Jeong-Ann
authors.initials: JA
authors.lastname: Park
authors.forename: Song-Bae
authors.initials: SB
authors.lastname: Kim
mesh_terms: D001151:Arsenic / Q000302:isolation & purification*; D001419:Bacteria; D002244:Carbon / Q000737:chemistry*; D007501:Iron / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000302:isolation & purification*
chemical_list: D014874:Water Pollutants, Chemical; D002244:Carbon; D007501:Iron; D001151:Arsenic