为评价不同环境条件下黑土胶体在地下水多孔介质中的运移,采用离心法对采自于黑龙江海伦黑土样品中的胶体颗粒进行提取.通过胶体在石英砂填充柱中的淋溶试验研究了pH、离子强度和溶解性有机质等环境因子对胶体在多孔介质中运移特性的影响.结果表明:当pH在4~9的范围内变化时,MR(回收率)和k(沉积速率系数)没有发生显著变化,即其对胶体运移能力影响不显著.随着离子强度从0.001 mmol/L升至1 mmol/L,黑土胶体穿透曲线MR降低,k值升高,说明高无机离子强度使胶体易于沉积在石英砂表面,运移能力降低.当溶液中含有溶解性有机质HA(胡敏酸)和FA(富里酸)时,MR降低,k值增加,表明胶体运移能力受到抑制,并且FA对胶体颗粒运移的抑制作用比HA强.溶液离子强度、HA和FA含量对黑土胶体在饱和多孔介质中的运移过程影响较大,是影响地下水中胶体运移过程的关键环境因子.
Colloid was extracted by centrifugation from black soil samples collected from Hailun in Heilongjiang Province,in order to evaluate the migration behavior of the black soil in the groundwater under different environmental conditions.Leaching experiments were conducted with the colloid in quartz sand porous media to investigate the effects of environmental factors(pH,ionic strengths and dissolved organic matter of the bulk solution) on the transport and fate of black soil colloid in saturated porous media.The results suggested that the deposition rate coefficient(k) and the fraction of colloid recovered(MR) did not change significantly when the pH of the bulk solution changed from 4 to 9.MR decreased and k increased as the ionic strength of the bulk solution increased from 0.001 mmol/L to 1 mmol/L,which indicated that the inorganic ions made the black soil colloid deposit on the quartz sand surface rather than transport with the bulk solution.MR became lower and k became higher when the bulk solution contained dissolved organic matter.This suggested that dissolved organic matter restrained the transport of the colloid in porous media,and the inhibition of fulvic acid was stronger than that of humic acid.Ionic strengths and dissolved organic matter of the bulk solution greatly affect the transport and fate of black soil colloid in saturated porous media,and they are the key environmental factors for the transport of black soil colloid in the groundwater.