Influences of Freezing on the Reduction of Cr(Ⅵ) by Typical Components of Dissolved Organic Matter
The influences of freezing on the reduction of Cr( Ⅵ) by four typical components of dissolved organic matter(DOM), namely oxalic acid, tartaric acid, malic acid and citric acid, were investigated. The results show that under the condition of a low concentration in the experiments, Cr ( Ⅵ) in the aqueous solution cannot be reduced by those four organic acids. However, in the ice, the four organic acids all facili-tate to remove Cr(Ⅵ). Moreover, the removing effects gradually strengthens with the increasing concentration of organic acids. And the effects of these four organic acids rank as oxalic acid>tartaric acid>malic acid>citric acid. The concentration of inorganic salts and inorganic acid can inhibit the reduction of Cr(Ⅵ) by changing the thickness of liquid-like layers in the ice surface, but the inhibiting effect is independent of the kinds of inorganic salts. It is the initial pH of the solution and the structure of the organic acid that greatly influence the reduction of Cr(Ⅵ). Upon the experiment condition, the concentration factor of the freeze-concentration effect can reach 103 at least, which apparently facilitates the oxalic acid to remove Cr(Ⅵ) in the ice.
国家科技期刊平台
NSTL
万方数据
维普
