蒙脱石电渗微观机理试验研究

为了在微观上探究电渗的作用机理，以单一矿物成分的蒙脱石为电渗对象，采用自制金属电极和EKG电极，设计4组平行试验，探讨土体离子迁移、电学参数、膨胀性能等物理化学方面的变化.试验结果表明，Al3+迁移能力远大于Cu2+和Fe2+，后两者难以在电场力的作用下移动，电极反应生成的金属离子对电渗排水基本没有促进作用；电渗削弱了蒙脱石的乙二醇膨胀性，且除铜电极外，铝、铁、EKG电极下电渗对靠近阴极的土的膨胀性抑制作用更强；电渗作用降低了蒙脱石的zeta电位绝对值；铝电极下Al3+的渗入严重降低了Ca2+的排出量，铁电极下Fe3+和Fe2+的渗入束缚了阳极附近土体中Na+的迁移；铁电极和EKG电极对土体有酸化作用，而铜电极、铝电极则不然.
Abstract: Single mineral montmorillonite was taken as electro-osmosis object to explore the microcosmic mechanism of electro-osmosis. Four sets of parallel tests were designed using self-made metal electrodes and EKG (electro-kinetic geosynthetics) electrodes. The results of electro-osmosis were analyzed; the changes of the physicochemical aspects such as ion migration, electrical parameters and swelling properties were discussed. The experimental results show that Al3+ migration ability is much greater than Cu2+ and Fe2+, the latter two are difficult to move under the action of electric field force, the metal ions produced by the electrode reaction have little effect on the electro-osmotic drainage; the electro-osmosis weakened the ethylene glycol expansibility of montmorillonite, and in addition to the copper electrode, electro-osmosis under the aluminum, iron, EKG electrode has stronger inhibition on the expansion of soil near the cathode; the electro-osmotic effect reduced the absolute value of zeta potential of montmorillonite; the infiltration of Al3+ in the aluminum electrode seriously reduced the emission of Ca2+, and the infiltration of Fe3+ and Fe2+ in the iron electrode constrained the migration of Na+ in the soil near the anode. The iron electrode and the EKG electrode have acidification effect on the soil, while the copper and aluminum electrodes are not so.