应用介孔分子筛材料(MCM-41)对土壤重金属污染的改良

采用盆栽试验,研究了无机分子筛材料(介孔分子筛,MCM-41)对重金属Cd、Pb和Cu污染土壤小白菜生长及土壤重金属各形态分布特征的影响。结果表明,无机分子筛材料对重金属Cd、Pb和Cu污染土壤的改良效果较明显,可明显增加小白菜产量,提高小白菜品质。土壤施加无机分子筛材料后,土壤Cd、Pb和Cu的BCR三形态中,酸可溶态(B1态)含量均降低,有机结合态(B3态)含量增加,而氧化物结合态(B2态)含量变化不显著。无机分子筛材料对土壤中Cd、Pb和Cu有效态具有较好的吸附钝化作用,可有效地抑制Cd、Pb和Cu在小白菜体内的积累。

Amendment of Heavy Metals in Contaminated Soil by MCM-41

Contamination of soils with heavy metals and metalloids is a widespread problem all over the world.Chemical immobilization,an in situ remediation method where used to reduce contaminant solubility in contaminated soil,has gained attention.We investigated the effectiveness of mesoporous molecular material(MCM-41)to reduce extractability and plant bioavailability in three Cd-,Pb-,and Cu-contaminated soils from vegetable garden soil.Three different concentrations of MCM-41(0.15%,0.3%,and 45% by weight(w/w))were applied.After a three weeks equilibration period,test plant(pakchoi)was grown on the soil.Growth parameters were determined and heavy metals contents of plant were performed.Exchangeable metal contents in soil decreased with increasing MCM-41 application.Plant growth was partly improved and the pakchoi dry weight increased significantly.The concentrations of "toxic" metals in the leaves of the test plant decreased after MCM-41 application.The soils treated with MCM-41were extracted with a three-step sequential extraction procedure representing acetic acid(HOAc)-soluble,reducible and oxidisable fractions of the heave metals.And the MCM-41 could decrease the soluble fractions of Cd,Pb,and Cu,while it could increase the oxidisable fractions of the heavy metals in soil.It maybe concluded that the application of the amendment could effectively restrain the migration and accumulation of heavy metals,especially,Cd,Pb and Cu in soil towards the vegetables.These results illustrate that MCM-41 application for the remediation of metal contaminated soils can be effective.