title: Background species effect on aqueous arsenic removal by nano zero-valent iron using fractional factorial design.
abstract: This study describes the removal of arsenic species in groundwater by nano zero-valent iron process, including As(III) and As(V). Since the background species may inhibit or promote arsenic removal. The influence of several common ions such as phosphate (PO4(3-)), bicarbonate (HCO3-)), sulfate (SO4(2-)), calcium (Ca2+), chloride (Cl-), and humic acid (HA) were selected to evaluate their effects on arsenic removal. In particular, a 2(6-2) fractional factorial design (FFD) was employed to identify major or interacting factors, which affect arsenic removal in a significant way. As a result of FFD evaluation, PO4(3-) and HA play the role of inhibiting arsenic removal, while Ca2+ was observed to play the promoting one. As for HCO3- and Cl-, the former one inhibits As(III) removal, whereas the later one enhances its removal; on the other hand, As(V) removal was affected only slightly in the presence of HCO3- or Cl-. Hence, it was suggested that the arsenic removal by the nanoiron process can be improved through pretreatment of PO4(3-) and HA. In addition, for the groundwater with high hardness, the nanoiron process can be an advantageous option because of enhancing characteristics of Ca2+.
authors.affiliation: Department of Chemical Engineering, Faculty of Engineering, Thammasat University, Pathumthani, Thailand.
authors.forename: Visanu
authors.initials: V
authors.lastname: Tanboonchuy
authors.forename: Nurak
authors.initials: N
authors.lastname: Grisdanurak
authors.forename: Chih-Hsiang
authors.initials: CH
authors.lastname: Liao
mesh_terms: D001151:Arsenic / Q000737:chemistry*; D001639:Bicarbonates / Q000737:chemistry; D002118:Calcium / Q000737:chemistry; D002712:Chlorides / Q000737:chemistry; D060587:Groundwater; D006812:Humic Substances; D007501:Iron / Q000737:chemistry*; D049329:Nanostructures / Q000737:chemistry*; D010710:Phosphates / Q000737:chemistry; D013431:Sulfates / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D018508:Water Purification / Q000379:methods
chemical_list: D001639:Bicarbonates; D002712:Chlorides; D006812:Humic Substances; D010710:Phosphates; D013431:Sulfates; D014874:Water Pollutants, Chemical; D007501:Iron; D001151:Arsenic; D002118:Calcium