膨润土系隔离材料对硝酸铅与苯酚运移的阻滞作用

Blocking Effect of Bentonite Isolation Material on the Transport of Lead Nitrate and Phenol

为提升膨润土-风积沙隔离材料对污染物的运移阻滞效果,制备了膨润土-风积沙-硅藻土复合隔离材料(SBD)、膨润土-风积沙-粉煤灰复合隔离材料(SBF)与膨润土-风积沙复合隔离材料(SB),采用柱模拟试验研究3种复合材料对硝酸铅和苯酚的阻滞效果。研究表明:(1)单一污染条件下,随着污染物浓度增加,SBF对硝酸铅的阻滞明显,硝酸铅的扩散系数最低,SBD对苯酚阻滞明显,苯酚的扩散系数最低;(2)双重污染条件下,扩散系数均大于单一污染,苯酚和硝酸铅之间存在促进扩散的现象;(3)3种材料对硝酸铅的阻滞因子大于苯酚,硝酸铅更容易被阻滞;(4)隔离材料对污染物的阻滞作用主要表现为离子交换、吸附作用和降低污染物的分子扩散。该研究可为双重污染场地提供隔离材料参考。

In order to improve the migration retardation effect of bentonite-aeolian sand isolation material on pollutants,the bentonite-aeolian sand-diatomite composite isolation material(SBD),bentonite-aeolian sand-fly ash composite isolation material(SBF)and bentonite-aeolian sand composite isolation material(SB)were prepared.The column simulation test was used to study the retardation effect of three composite materials on the lead nitrate and phenol.The results showed that,under the condition of single pollution,with the pollutant concentration increasing,SBF blocked the lead nitrate obviously,and the diffusion coefficient of lead nitrate was the lowest.SBD blocked the phenol obviously,and the diffusion coefficient of phenol was the lowest.Under the condition of double pollution,the diffusion coefficient was greater than that of the single pollution,and there was a phenomenon of promoting diffusion between the phenol and lead nitrate.The retardation factor of the three materials to lead nitrate was greater than that of the phenol,and the lead nitrate was more easily blocked.The blocking effect of isolation materials on pollutants was mainly manifested as ion exchange,adsorption and reduction of molecular diffusion of pollutants.This study could provide isolation material reference for double contaminated sites.