采用平衡透析法和Dom(浓度分配系数)研究土壤提取的HA(腐殖酸)与Sb(Ⅲ)的络合特征及作用机理.结果表明:在Sb(Ⅲ)与HA络合过程中,4 h左右透析管内外ρ〔Sb(Ⅲ)〕达到物理平衡,72 h左右达到络合平衡状态.当pH为4.0时,Dom最大达7.33 Lg,Sb(Ⅲ)与HA络合能力最强;当pH为2.0~4.0时,Sb(Ⅲ)与HA的络合能力几乎不受pH影响;当pH为5.0~8.0时,Sb(Ⅲ)与HA的络合能力随着pH的增大而显著减小;当pH为4.0时,Sb(Ⅲ)与HA之间的络合能力随着HA溶液中ρ(DOC)的增加而加强.红外光谱表征反应物的研究结果证明,HA与Sb(Ⅲ)的结合点主要发生在羧基和酚羟基之间.
The complexation behaviors of Sb ( Ⅲ ) with humic acid ( HA ) extracted from the soil were investigated by the method of equilibrium dialysis and conditional distribution coefficients (Dora). The results showed that the internal and external Sb (Ⅲ) concentrations of dialysis pipe balanced about 4 hours, and the complexation between Sb( Ⅲ ) and HA achieved equilibrium within 72 hours. The maximum complexation capacity (7. 33 L/g) was gained at pH 4. 0. The pH almost had no effect on the complexation between Sh( Ⅲ) and HA in its range of 2. 0-4. 0. The complexation between Sb( Ⅲ ) and HA, however, significantly decreased with the increase of pH in the range of4. 0-8.0. The complexation between Sb( Ⅲ ) and HA enhanced by the increase of dissolved organic carbon contents (p(DOC)) in the solution of HA at pH 4.0. Furthermore, ATR-IR spectra analysis results suggested the involvement of carboxykl of aromatic ring and phenolic hydroxyl group in the complexation of Sb( Ⅲ ) with HA.