The coupling effects of electric field and clay mineralogy on clay aggregate stability
The coupling effects of electric field and clay mineralogy on clay aggregate stability
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DOI：
10.1007/s11368-015-1063-0
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发表时间：
2015-02
影响因子：
3.6
通讯作者：
Chenyang Xu;Zhenghong Yu;Hang Li
中科院分区：
文献类型：
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作者：
Chenyang Xu;Zhenghong Yu;Hang Li
本文以蒙脱石、高岭石及其不同质量比的复合体为实验材料，研究了在电解质溶液中考虑土壤颗粒表面电场的情况下，粘土矿物学对团聚体稳定性的影响。在不同的电解质浓度下的聚集体分解的程度进行了定性和定量评价。用视频显微镜观察骨料破碎过程。根据Stokes方程计算了粒径<10 μ m、<5 μ m和<2 μm的颗粒（微团聚体和单颗粒）占样品总质量的百分比。(1)粘土化合物团聚体破碎后释放的小颗粒数量是蒙脱石团聚体的数倍。(2)在高表面电位条件下，团聚体以爆炸方式破碎，且爆炸临界表面电位值随团聚体中高岭石含量的增加而增大。(3)在高表面电位下，高岭石含量高的粘土复合团聚体释放颗粒的含量远高于高岭石含量低的粘土复合团聚体。结论电场与粘土矿物学的耦合作用决定了蒙脱石和粘土复合体团聚体的稳定性。这说明在强降雨条件下，粉粒含量较高的土壤团聚体比粘粒含量较高的土壤团聚体稳定性差;侵蚀性最强的土壤可能不是粘粒土，而是粉粒土，特别是长期干旱后突发暴雨下的粉粒土。
PurposeThis paper aims to investigate the effect of clay mineralogy on aggregate stability under the consideration of soil particle surface electric field in electrolyte solution.Materials and methodsAggregates of montmorillonite, kaolinite, and their compounds in different mass ratio were used as experimental materials. The degree to which the aggregates broke down under different electrolyte concentrations was evaluated both qualitatively and quantitatively. The aggregate breakdown process was observed with a video microscope. Furthermore, the percentage of particles (micro-aggregates and single particles) in diameter of <10, <5, and <2 μm to the total sample mass were measured based on Stokes equation.Results and discussionDifferent electrolyte concentrations correspond to different surface potential values around the particle surface. (1) The amount of released small particles for aggregate of clay compounds was several times higher than that for montmorillonite aggregate after breakdown. (2) Under high surface potential conditions, aggregate breakdown in a way of explosion was observed, and the critical surface potential values for the explosion increased with the increase of kaolinite content in aggregates. (3) The content of released particles for clay compound aggregates with high kaolinite content was much higher than that for aggregates with low kaolinite content under high surface potential values.ConclusionsThe coupling effects of electric field and clay mineralogy determined the aggregate stability of montmorillonite and clay compounds. This indicated that soil aggregates with relatively high silt content would be less stable than those with relatively high clay content under heavy rainfall; the most erosive soil might not be clay soils, but the silt soils, especially those under sudden storm after long-time drought.