Effect of organic matter on mobilization of antimony from nanocrystalline titanium dioxide

Antimony (Sb) is of increasing environmental concern worldwide. The sorption behavior of Sb was investigated. Both Sb(III) and Sb(V) were likely to be sorbed onto nanocrystalline titanium dioxide (TiO₂). Sorption studies showed that the Sb(V) sorption capacity and rate for TiO₂ were greater than those of Sb(III). The highest Sb(III) and Sb(V) sorption on TiO₂, on the basis of the Langmuir equation, were 333 and 588 mmol kg^-1, respectively. The study suggested that TiO₂ is an effective adsorbent for Sb removal. In addition, Sb mobilization in the presence of humic acid (HA) was found to be highly pH-dependent. For pH values of 9-11, the addition of HA enhanced Sb mobilization significantly. The results highlight the importance of organic matter in the mobilization of Sb in alkaline-contaminated environments.