铜离子在饱水细砂中的吸附研究

Study on Adsorption of Cu2+ in Fine Sand with Saturated Water

[目的]了解Cu2+在饱水细砂中的吸附特征,预测地下水中Cu2+的发展演化趋势。[方法]通过室内土柱试验,观察非吸附组分(Cl-)和吸附组分(Cu2+)在渗流中半浓度出现的时间,进而计算分配系数、滞后系数,研究Cu2+在饱水细砂中的吸附特征。[结果]细砂的阳离子吸附交换容量约为8.7 meq/100 g,若被吸附物质全部为Cu2+,则100 g细砂中大约可吸附0.126 g Cu2+,可见饱水细砂对Cu2+的吸附能力较强。该细砂土的分配系数为52.0,滞后系数为138.1,远大于1.0,说明吸附作用对Cu2+迁移的影响较大,与非吸附物质相比,其弥散系数和溶质迁移速度均降低了138.1倍,从而缓减了Cu2+在地下水中的迁移速度。[结论]吸附作用对Cu2+在饱水细砂中迁移的影响较大。

[ Objective ] The aim was to understand the adsorption characteristic of Cu^2＋ in fine sand with saturated water and forecast the trend on development and evolution of Cu^2＋ in the ground water. [ Method] In the laboratory soil column experiment, the appearance time of 50% effective concn, of non-adsorption component （Cl^-） and adsorption component （Cu^2＋ ） in seepage were observed, the partition coefficient and lag coefficient were calculated and the adsorption characteristic of Cu^2＋ in the fine sand with saturated water was studied. [ Result] The absorption and exchange capacity of cation in the fine sand was about 8.7 meq/100 g. If the adsorbed substance was Cu^2＋ entirely, about 0. 126 g Cu^2＋ . could be absorbed in every 100 g fine sands, which showed that fine sand with saturated water had stronger absorption capability to Cu^2＋ . The partition coefficient of the fine sand soil was 52.0, lag coefficient was 138.1, being much higher than 1.0, which showed that the influence of absorption on the Cu^2＋ migration was larger and its diffusion coefficient and solute migration velocity were all decreased by 138.1 times compared with that of the non-adsorption substance, thereby delayed lhe migration velocity of Cu^2＋ in the ground water. [ Conclusion] The influence of absorption on the Cu^2＋ migration in the fine sand with saturated water was larger.