Preparation and evaluation of Zr-beta-FeOOH for efficient arsenic removal.
A Zr-beta-FeOOH adsorbent for both As(V) and As(III) removal was prepared by a chemical co-precipitation method. Compared with beta-FeOOH, the addition of Zr enhanced the adsorption capacities for As(V) and As(III), especially As(III). The maximum adsorption capacities for As(III) and As(V) were 120 and 60 mg/g respectively at pH 7.0, much higher than for many reported adsorbents. The adsorption data accorded with Freundlich isotherms. At neutral pH, for As(V), adsorption equilibrium was approached after 3 hr, while for As(III), adsorption equilibrium was approached after 5 hr. Kinetic data fitted well to the pseudo second-order reaction model. As(V) elimination was favored at acidic pH, whereas the adsorption of As(III) by Zr-beta-FeOOH was found to be effective over a wide pH range of 4-10. Competitive anions hindered the adsorption according to the sequence: phosphate > silicate > bicarbonate > sulfate > nitrate, while Ca2+ and Mg2+ increased the removal of As(III) and As(V) slightly. The high adsorption capability and good performance in other aspects make Zr-beta-FeOOH a potentially attractive adsorbent for the removal of both As(III) and As(V) from water.
State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences Beijing 100085, China. hbsdsxf@163.com
Xiaofei
X
Sun
Chun
C
Hu
Jiuhui
J
Qu
D000327:Adsorption; D000838:Anions; D001151:Arsenic / Q000302:isolation & purification*; D002412:Cations; D006812:Humic Substances / Q000032:analysis; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D046529:Microscopy, Electron, Transmission; D012967:Sodium Dodecyl Sulfate / Q000737:chemistry; D013696:Temperature; D014867:Water / Q000737:chemistry; D014961:X-Ray Diffraction; D015040:Zirconium / Q000737:chemistry*
D000838:Anions; D002412:Cations; D006812:Humic Substances; D014867:Water; D012967:Sodium Dodecyl Sulfate; D015040:Zirconium; D001151:Arsenic