两种铁基材料对污染农田土壤砷、铅、镉的钝化修复

制备得到了铁钙（FeCa）和铁锰（FMBO）两种铁基材料，用于钝化修复As、Pb和Cd污染土壤.研究采集了来自绍兴上虞（SY）、广东佛山（FS）、广东韶关（SG）、湖南浏阳（LY）、江西赣州（GZ）、贵州独山（DS）和安徽马鞍山（MAS）的7种重金属污染水稻土（潮泥土），通过土壤培养试验，研究铁钙材料（FeCa）和铁锰材料（FMBO）对各类土壤溶液中As、Pb和Cd浓度动态变化的影响，对土壤中有效态As、Pb和Cd钝化效果的影响，以及在不同种类土壤中有效态As、Pb和Cd钝化效果差异及影响因素.结果表明，培养过程中，铁基材料处理下土壤溶液中As、Pb和Cd浓度均低于对照处理.研究发现，两铁基材料均能对土壤中As、Pb和Cd起到较好的钝化作用，相同添加量下，铁钙材料对土壤As的钝化效率优于铁锰材料，而材料之间对土壤Pb和Cd钝化效率无显著差异.铁钙材料处理下各种土壤As钝化效果表现为GZ > SG > DS和MAS，土壤铅钝化效果表现为FS>SY、LY和SG>MAS，土壤镉钝化效果表现为SY、GZ和DS>MAS；铁锰材料处理下各种土壤As钝化效果表现为SY、LY和GZ > DS > FS，土壤Pb钝化效果表现为FS > GZ > SY，土壤Cd钝化效果表现为DS > LY > MAS.各种土壤As钝化效率在两铁基材料处理下均与土壤黏土含量呈显著负相关，各种土壤Pb钝化效率在两铁基材料处理下均与土壤pH呈显著正相关，各种土壤Cd钝化效率在铁钙材料处理下与土壤黏土含量显著负相关.总体来看，两铁基材料均适用于各不同种类As、Pb和Cd污染土壤的治理.

Simultaneous Immobilization of Arsenic, Lead, and Cadmium in Paddy Soils Using Two Iron-based Materials

Two iron-based materials, Fe-Ca composite (FeCa) and Fe-Mn binary oxide (FMBO), were applied to immobilize As, Pb, and Cd in heavy metal contaminated paddy soils. Seven kinds of paddy soil (tidal soil) contaminated by arsenic, lead and cadmium were collected from Shangyu, Shaoxing (SY), Foshan, Guangdong (FS), Shaoguan, Guangdong (SG), LiuYang, Hunan (LY), Ganzhou, Jiangxi (GZ), Dushan, Guizhou (DS), and Ma''anshan, Anhui (MAS). The effects of iron-based materials on the dynamic changes of As, Pb, and Cd concentration in soil solution, the stabilization efficacy of available As, Pb, and Cd in soil, and the effects of soil types and properties on stabilization efficacy were studied through soil incubation experiment. The results showed that the content of soil dissolved As, Pb, and Cd were lower in iron-based material treatments than in control throughout the incubation. The addition of two iron-based materials significantly reduced the availability of Cd, Pb, and As. Moreover, the stabilization efficiency of FeCa for As was higher than FMBO, but no significant difference was found in the stabilization efficiency of Pb and Cd between two materials. The stabilization efficiency of As, Pb, and Cd in FeCa treatments could be ordered as GZ > SG > DS and MAS; FS>SY, LY, and SG>MAS; SY, GZ, and DS>MAS, respectively. While the stabilization efficiency for As, Pb, and Cd in FMBO could be ordered as SY, LY, and GZ > DS > FS; FS > GZ > SY; DS > LY > MAS, respectively. In addition, the statistical results showed that the stabilization efficiencies of various soils under the treatment of iron-based materials were significantly correlated with sand content (negatively correlated for As), soil pH (positively correlated for Pb), and clay content (negatively correlated for Cd). In conclusion, the two iron-based materials evaluated in this study may be effective stabilization agents for remediating different types of arsenic-, lead-, and cadmium-contaminated soils.