聚丙烯酰胺改良土-膨润土的渗透性及对苯酚的吸附

为提高土-膨润土(SB)隔离屏障的渗透性及其对苯酚的吸附效果,制备一种聚丙烯酰胺改良土-膨润土(PSB)。研究聚丙烯酰胺掺量、苯酚浓度、干湿作用、冻融作用对PSB隔离屏障渗透系数的影响及对苯酚的吸附效果,并从微观层次揭示其作用机理。结果表明:苯酚浓度对PSB隔离屏障渗透系数没有影响;干湿作用下PSB隔离屏障渗透系数增加但仍保持在同一个数量级,而冻融作用下隔离屏障渗透系数增大1~2个数量级;聚丙烯酰胺可使干湿、冻融作用下隔离屏障的渗透系数有所降低,即可有效抑制干湿、冻融的破坏作用;掺加0.7%(质量分数)聚丙烯酰胺的PSB隔离屏障对苯酚的吸附率可达69%以上,相比SB隔离屏障吸附率约提高50%,且随着苯酚污染液浓度增加,吸附率逐渐提高。该研究可为苯酚污染的隔离与封闭提供理论依据与参数支持。

Permeability of Polyacrylamide Modified Soil-Bentonite and Its Adsorption of Phenol

In order to improve the permeability of the soil-bentonite (SB) isolation barrier and its adsorption effect on phenol, a polyacrylamide modified soil-bentonite (PSB) was prepared. The effects of polyacrylamide content, phenol concentration, dry-wet cycles and freeze-thaw cycles on the permeability coefficient of PSB isolation barrier and the adsorption effect on phenol were studied, and the mechanism of these effects were revealed at micro level. The results show that phenol concentration has no effect on permeability coefficient of PSB isolation barrier. The permeability coefficient of PSB isolation barrier increases under dry-wet cycles but remains the same order of magnitude. The permeability coefficient of PSB isolation barrier increases by 1~2 orders under freeze-thaw cycles. Polyacrylamide reduces the permeability coefficient of PSB isolation barrier under dry-wet cycles and freeze-thaw cycles, indicating that it can effectively restrain the destructive effects of dry-wet cycles and freez-thaw cycles. The adsorption rate of phenol on the PSB isolation barrier with 0.7% (mass fraction) polyacrylamide reaches over 69%, which is about 50% higher than that on the SB barrier, and gradually increases with the increase of concentration of phenol contaminated solution. The research can provide theoretical basis and parameter support for isolation and closure of phenol pollution.