@article{fdi:010053829,
  title = {{D}istinctive arsenic({V}) trapping modes by magnetite nanoparticles induced by different sorption processes},
  author = {{W}ang, {Y}. {H}. and {M}orin, {G}. and {O}na-{N}guema, {G}. and {J}uillot, {F}arid and {C}alas, {G}. and {B}rown, {G}. {E}.},
  editor = {},
  language = {{ENG}},
  abstract = {{A}rsenic sorption onto iron oxide spinels such as magnetite may contribute to arsenic immobilization at redox fronts in soils, sediments, and aquifers, as well as in putative remediation and water treatment technologies. {W}e have investigated {A}s({V}) speciation tresulting from different sorption processes on magnetite nanoparticles, including both adsorption and precipitation, using {X}-ray absorption fine structure ({XAFS}) spectroscopy and transmission electron microscopy ({TEM}). {XAFS} results suggest that {A}s{O}4 tetrahedra form predominantly inner sphere bidentate corner sharing ({C}-2) complexes and outer-sphere complexes on magnetite in the adsorption experiments. {I}n the precipitation experiments, an increasing fraction of {A}s{O}4 tetrahedra appears to be incorporated in clusters having a magnetite-like local structure with increasing {A}s loading, the remaining fraction of {A}s being adsorbed at the surface of magnetite particles. {I}n the sample with the highest {A}s loading (15.7 mu mol/m(2)) {XAFS} data indicate that {A}s({V}) is fully incorporated in such clusters. {S}uch processes help to explain the significantly higher arsenic uptake in precipitation samples compared to those generated in adsorption experiments. {I}n addition, for the precipitation samples, {TEM} observations indicate the formation of amorphous coatings and small (similar to 3 nm) nanoparticles associated with larger (similar to 20-40 nm) magnetite nanoparticles, which are absent in the adsorption samples. {T}hese results suggest that {A}s({V}) could form complexes at the surfaces of the small nanoparticles and could be progressively incorporated in their structure with increasing {A}s loading. {T}hese results provide some of the fundamental knowledge about {A}s({V})-magnetite interactions that is essential for developing effective water treatment technologies for arsenic.},
  keywords = {},
  booktitle = {},
  journal = {{E}nvironmental {S}cience and {T}echnology},
  volume = {45},
  numero = {17},
  pages = {7258--7266},
  ISSN = {0013-936{X}},
  year = {2011},
  DOI = {10.1021/es200299f},
  URL = {https://www.documentation.ird.fr/hor/fdi:010053829},
}