pH对滨海含水介质胶体迁移-沉积的影响

室内土柱试验采用天津滨海地区具有代表性的土样为研究对象,探讨pH对胶体在含水介质中迁移-沉积行为的影响。结果表明,pH为6.90和11.70的胶体穿透曲线呈"S"型,而pH为3.00时呈反"S"型;胶体的穿透曲线与示踪离子相比,存在一个临界孔隙体积数(临界点),在临界点之前胶体的迁移速度大于示踪离子,之后则相反;胶体在含水介质迁移过程中发生了沉积,沉积量随孔隙体积数的增加而增加;pH=3.00胶体的总沉积率为90.24%,是pH=6.90和pH=11.70胶体的2~3倍,后二者的总沉积率大小相近。酸性环境下,沉积作用在胶体迁移过程中一直占主导地位,中性和酸性环境中,胶体沉积作用则相对较小。

Effect of pH on Colloid Transport-Deposition of Porous Medium in Coastal Region

Column experiment with nature porous media in coastal region of Tianjin was conducted to elucidate the effect of pH on the mobility and deposition of colloids. Results showed that the colloid breakthrough curve under pH 6.90 and 11.70 appeared "S"curves,whereas that of pH 3.00 was a counter curve. The transports of colloidal particles were faster than that of the tracer before the critical pore volumes (CPV),then on the contrary. The increased deposition of colloids with increasing acidity of solution was well established,and the deposition capacity of colloid increased with increasing pore volumes.