【摘要】 为探究地下水中腐植酸（HA）和Cd²⁺复合污染物对黏土胶粒在饱和多孔介质中迁移的影响,本文选择蒙脱石和高岭石两种黏土胶粒作为研究对象,采用同步注射柱实验,在饱和石英砂柱中分别同步注射黏土胶粒与腐植酸、Cd²⁺或腐植酸+Cd²⁺混合液,来研究腐植酸和Cd²⁺与黏土胶粒的共迁移。结果显示:高岭石在石英砂柱中的沉降速度依次为:无Cd²⁺无腐植酸（3.72 min-1）>仅有Cd²⁺（2.82 min-1）>Cd²⁺与腐植酸共存（2.01 min-1）>仅有腐植酸（0.46 min-1）;蒙脱石在石英砂柱中的沉降速度依次为:无Cd²⁺无腐植酸（1.02 min-1）>仅有Cd²⁺（0.97 min-1）>Cd²⁺与腐植酸共存（0.85 min-1）>仅有腐植酸（0.30 min-1）。研究结果表明,腐植酸和Cd²⁺对蒙脱石和高岭石胶粒的迁移效果比较一致,它们均能促进两种黏土胶粒的迁移,促进作用腐植酸最强而Cd²⁺较弱;腐植酸和Cd²⁺之间存在拮抗作用,即二者的加合作用反而小于腐植酸单独作用。通过对黏土胶粒的粒径和Zeta电位进行测试分析,可推测腐植酸和Cd²⁺是通过不同的机理来促进黏土胶粒的迁移:腐植酸通过改变黏土胶粒表面的电性来抑制黏土胶粒的沉降,而Cd²⁺通过促使黏土胶粒聚凝来降低其沉降。这些发现有助于更好地理解天然土壤胶粒在环境中的迁移和浓度分布。更多还原

【Abstract】 With the aim to explore the impact of humic acid（HA）and cadmium ion(Cd²⁺)on the transport of clay colloids in saturated porous media, co-transport column experiments were performed using montmorillonite and kaolinite colloids as surrogates. Results showed that the deposition rate of kaolinite colloids was the highest in the absence of HA and Cd²⁺（3.72 min-1）, lower in the presence of only Cd²⁺（2.82 min-1）, even lower in the presence of both HA and Cd²⁺（2.01 min-1）, and the lowest in the presence of only HA（0.46 min-1）. The similar trend in changing deposition rate in response to the variability of Cd²⁺and/or HA was also observed for montmorillonite colloids, i.e., the rate was 1.02 min-1in the absence of HA and Cd²⁺, 0.97 min-1in the presence of only Cd²⁺, 0.85 min-1in the presence of both HA and Cd²⁺,and 0.30 min-1in the presence of only HA. These results demonstrated the consistent role of HA and Cd²⁺in the mobility of both clay colloids; HA and Cd²⁺both promoted the transport of the two clay colloids. The effect of HA was stronger than that of Cd²⁺. Moreover, an antagonistic interaction between humic acid and cadmium ions occurred, rendering the combined effect of the two lower than that of only HA.Based on the particle size and zeta potential measurement of the clay colloids, we speculated that HA and Cd²⁺promoted the colloid mobility via different mechanisms:HA achieved this by modifying the surface electrical properties of the clay colloids, while Cd²⁺achieved this by inducing particle aggregation. These findings improve current knowledge on the translocation and concentration distribution of natural soil colloids in the environment.更多还原