多种材料对铅镉污染农田土壤原位修复效果的研究

Comparison of several amendments for in-situ remediation of lead-and cadmium-contaminated farmland soil

为选取费效比高的铅镉污染农田土壤修复材料,研究比较了黏土矿物和生物炭不同组合:硅藻土(Diatomite,D)、膨润土(Bentonite,BE)、海泡石(Sepiolite,S)、人造沸石(Artificial zeolite,AZ)、羟基磷灰石(Hydroxyapatite,HA)、生物炭(Biochar,B)、硅藻土+生物炭(Diatomite/Biochar,DB)、膨润土+生物炭(Bentonite/Biochar,BEB)、海泡石+生物炭(Sepiolite/Biochar,SB)、人造沸石+生物炭(Artificial zeolite/Biochar,AZB)以及羟基磷灰石+生物炭(Hydroxyapatite/Biochar,HAB)等修复材料对农田土壤中铅镉的原位修复效果并对修复前后铅镉形态分布和土壤理化性质变化进行了跟踪。结果表明,修复21 d后,上述各修复材料对铅修复率大小顺序依次为:HA>D>AZ>BE>S>DB>BEB>AZB>SB>HAB>B,对镉修复率大小顺序依次为:SB>AZB>B>HAB>BEB>D>S>BE>AZ>HA>DB;各修复材料均能提高铅、镉残渣态(RS)的比例。以HA为代表的黏土矿物在原位修复铅污染农田土壤有明显优势,含生物炭的修复材料在原位修复镉污染农田土壤中有明显优势,SB和AZB适合用于铅镉复合污染农田土壤,处理后农田土壤理化性质未发生较大变化。

Cost-efficiency of in-situ remediation of lead(Pb)-and cadmium(Cd)-contaminated farm soil using amended materials was assessed.The effects of ordinary diatomite(D),bentonite(BE),sepiolite(S),artificial zeolite(AZ),and hydroxyapatite(HA)were comparedagainst those of biochar(B),diatomite/biochar(DB),bentonite/biochar(BEB),sepiolite/biochar(SB),artificial zeolite/biochar(AZB),andhydroxyapatite/biochar(HAB)on the immobilization of Pb-and Cd-contaminated farmland soil.After 21 d of remediation by these meth?ods,experiments with diethylenetriaminepentaacetic acid(DTPA)showed that Pb and Cd bioaccessibilities decreased by 25.7%~83.4% and 8.4%~34.2%respectively.The order of Pb immobilization was found to be HA >D >AZ >BE >S>DB >BEB >AZB >SB>HAB >B,andthe order of Cd immobilization was found to be SB >AZB >B >HAB >BEB >D >S >BE >AZ >HA >DB.Moreover,the sequential extraction procedure indicated that all of the above materials could increase the proportion of Pb and Cd residual states.HA,which is a clay miner?al,had a distinct advantage in in-situ remediation of Pb-contaminated farmland soil,whereas the same was true for clay minerals and bio?char with regard to the in-situ remediation of Cd-contaminated farmland soil.SB and AZB showed distinct advantages in the in-situ remedi?ation of Pb-and Cd-contaminated farmland soil.After treatment,the farm soils’physical and chemical properties did not change significantly.