4种金属离子对高岭土胶体上蒽分布的影响

在水/土比10、180r/min振荡和室温28℃条件下,研究Fe3+、Cu2+、Zn2+、Ca2+对高岭土上蒽分布的影响.结果表明,高岭土对Fe3+、Cu2+、Zn2+、Ca2+的吸附平衡时间和平衡浓度分别为24h和(20 ± 3)mg/g.当金属离子负荷330mg/g时,上清液中高岭土胶体最低浓度为(40 ± 3)mg/L.添加Fe3+时,总胶体浓度从52mg/L增加到133mg/L;添加Cu2+或Zn2+时,总胶体浓度从52mg/L增加到110mg/L;添加Ca2+时,总胶体浓度从52mg/L增加到73mg/L.上清液中蒽浓度增加趋势与上清液中总胶体浓度的变化趋势一致,添加Fe3+时,蒽浓度从30ng/L增加到73ng/L;添加Cu2+或Zn2+时,蒽浓度从28,35ng/L增加到65,66ng/L;添加Ca2+时,蒽浓度从40ng/L增加到50ng/L.上清液中蒽浓度的增加趋势与所添加的金属电荷密度高低顺序一致(Fe3+ > Cu2+、Zn2+).在pH值为6.5时,Ca2+对增加上清液中蒽浓度能力最弱.

Effect of adding four metal ions on distribution of anthracene on kaolin colloid

In order to understand the effect of metal ions on distribution and adsorption of anthracene on soils (water/soil = 10), Fe3+, Cu2+, Zn2+ and Ca2+ were added in the colloid solution of contaminated kaolin to probe the varies of anthracene concentrations in supernatants after 180 r/min of shaking at 28℃. The adsorption equilibrium time and equilibrium concentration of Fe3+, Cu2+, Zn2+ and Ca2+ by kaolin were about 24 h and (20 ± 3) mg/g, respectively. When contents of metal ions added were more than 30 mg/g for kaolin, the lowest concentration of kaolin colloid was (40±3)mg/L in supernatant. The total colloid concentrations in supernatants increased from 52 mg/L to 133 mg/L for adding Fe3+, 52 mg/L to 110 mg/L for adding Cu2+ or Zn2+, and 52 mg/L to 73 mg/L for adding Ca2+, respectively. Meanwhile, the increasing trends of anthracene in the supernatants were similar to those of total colloid concentrations, which were from 30 ng/L to 73 ng/L for adding Fe3+, 28, 35ng/L to 65, 66 ng/L for adding Cu2+ or Zn2+, and 40 ng/L to 50 ng/L for adding Ca2+, respectively. Thus, the sequences of the increase of anthracene in supernatants were the same as those of the charge densities of metal ions (Fe3+ > Cu2+, Zn2+). However, adding Ca2+ at pH 6.5 only led to a minor increase of anthracene in supernatant.