Arsenite and arsenate adsorption on coprecipitated bimetal oxide magnetic nanomaterials: MnFe2O4 and CoFe2O4. Chemical Engineering Journal, 158, 599-607

State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Science, Chinese Academy of Sciences, Beijing 100085, China
Chemical Engineering Journal (Impact Factor: 4.32). 04/2010; 158(3):599-607. DOI: 10.1016/j.cej.2010.02.013

ABSTRACT Bimetal oxide magnetic nanomaterials (MnFe2O4 and CoFe2O4) were synthesized and characterized with transmission electron microscope (TEM), X-ray powder diffraction (XRD), vibrating sample magnetometer (VSM), and X-ray photoelectron spectroscopy (XPS). The adsorption of arsenic on these nanomaterials was studied as a function of pH, initial arsenic concentration, contact time and coexisting anions. The Langmuir and Freundlich isotherm models were applied to fit the adsorption data, and the maximum adsorption capacities of arsenite (AsIII) and arsenate (AsV) on MnFe2O4 were 94 and 90 mg g−1, and on CoFe2O4 were 100 and 74 mg g−1, respectively. MnFe2O4 and CoFe2O4 showed higher AsIII and AsV adsorption capacities than the referenced Fe3O4 (50 and 44 mg g−1, respectively) prepared by the same procedure. Quantificational calculation from XPS narrow scan results of O(1s) spectra of adsorbents indicated that the higher adsorption capacities of AsIII and AsV on MnFe2O4 and CoFe2O4 than on Fe3O4 might be caused by the increase of the surface hydroxyl (M–OH) species. Phosphate and silicate were powerful competitors with arsenic for adsorptive sites on the adsorbent. Desorption study showed that over 80% of AsIII and 90% of AsV could be desorbed from MnFe2O4 with 0.1 M NaOH solution.

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    • "Much larger Q m value of PS-Fe 3 O 4 further demonstrated that nano-Fe 3 O 4 particles , after being coated upon PS beads, were better dispersed and exhibited more active sites for arsenate adsorption. Zhang et al. [25] reported the maximum arsenate adsorption capacities of Fe 3 O 4 with diameter of ∼20 nm was 44 mg/g. Yavuz et al. [6] [7] [8] found that for As(V) removal, the maximum adsorption capacity of "
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    • "Natural arsenic (As) contamination in water supplies is a major environmental and health problem on a global scale and has become a challenge for the world scientists. Increasing concentrations of arsenic in groundwater and surface water have been reported from many regions of the world in recent years [1] [2] [3] [4] [5] [6] [7]. "
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