
<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="6.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Ha, Juyoung</style></author><author><style face="normal" font="default" size="100%">Trainor, Thomas P.</style></author><author><style face="normal" font="default" size="100%">Farges, François</style></author><author><style face="normal" font="default" size="100%">Brown, Gordon E.</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Interaction of Zn(II) with Hematite Nanoparticles and Microparticles: Part 2. ATR-FTIR and EXAFS Study of the Aqueous Zn(II)/Oxalate/Hematite Ternary System</style></title><secondary-title><style face="normal" font="default" size="100%">Langmuir</style></secondary-title><short-title><style face="normal" font="default" size="100%">Langmuir</style></short-title></titles><dates><year><style  face="normal" font="default" size="100%">2009</style></year><pub-dates><date><style  face="normal" font="default" size="100%">05/2009</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">25</style></volume><pages><style face="normal" font="default" size="100%">5586 - 5593</style></pages><abstract><style face="normal" font="default" size="100%">Sorption of Zn(II) to hematite nanoparticles (HN) (av diam = 10.5 nm) and microparticles (HM) (av diam = 550 nm) was studied in the presence of oxalate anions (Ox2−(aq)) in aqueous solutions as a function of total Zn(II)(aq) to total Ox2−(aq) concentration ratio (R = [Zn(II)(aq)]tot/[Ox2−(aq)]tot) at pH 5.5. Zn(II) uptake is similar in extent for both the Zn(II)/Ox/HN and Zn(II)/Ox/HM ternary systems and the Zn(II)/HN binary system at [Zn(II)(aq)]tot &lt; 4 mM, whereas it is 50−100% higher for the Zn(II)/Ox/HN system than for the Zn(II)/Ox/HM ternary and the Zn(II)/HN and Zn(II)/HM binary systems at [Zn(II)(aq)]tot &gt; 4 mM. In contrast, Zn(II) uptake for the Zn(II)/HM binary system is a factor of 2 greater than that for the Zn(II)/Ox/HM and Zn(II)/Ox/HN ternary systems and the Zn(II)/HN binary system at [Zn(II)(aq)]tot &lt; 4 mM. In the Zn(II)/Ox/HM ternary system at both R values examined (0.16 and 0.68), attenuated total reflectance Fourier transform infrared (ATR-FTIR) results are consistent with the presence of inner-sphere oxalate complexes and outer-sphere ZnOx(aq) complexes, and/or type A ternary complexes. In addition, extended X-ray absorption fine structure (EXAFS) spectroscopic results suggest that type A ternary surface complexes (i.e., &gt;O2−Zn−Ox) are present. In the Zn(II)/Ox/HN ternary system at R = 0.15, ATR-FTIR results indicate the presence of inner-sphere oxalate and outer-sphere ZnOx(aq) complexes; the EXAFS results provide no evidence for inner-sphere Zn(II) complexes or type A ternary complexes. In contrast, ATR-FTIR results for the Zn/Ox/HN sample with R = 0.68 are consistent with a ZnOx(s)-like surface precipitate and possibly type B ternary surface complexes (i.e., &gt;O2−Ox−Zn). EXAFS results are also consistent with the presence of ZnOx(s)-like precipitates. We ascribe the observed increase of Zn(II)(aq) uptake in the Zn(II)/Ox/HN ternary system at [Zn(II)(aq)]tot ≥ 4 mM relative to the Zn(II)/Ox/HM ternary system to formation of a ZnOx(s)-like precipitate at the hematite nanoparticle/water interface.</style></abstract><issue><style face="normal" font="default" size="100%">10</style></issue></record></records></xml>