淹水条件下赤铁矿对羟基磷灰石钝化土壤铜镉的影响

Effect of Hematite on HAP Immobilization of Soil Copper and Cadmium Under Flooding Conditions.

羟基磷灰石(HAP)通常用作重金属污染土壤的修复材料。但土壤中存在的铁氧化物与磷具有较强的结合能力,其是否会影响HAP对重金属的固定能力目前仍不明晰。该研究通过淹水培养实验,考察赤铁矿对HAP钝化铜镉效率的影响。结果表明,与对照相比,单一HAP和单一赤铁矿处理会增加土壤及其溶液的pH值。高含量赤铁矿的存在能够有效降低HAP处理土壤溶液中的磷酸盐、Cu和Cd含量,同时使土壤中有效磷含量降低12.9%~41.0%,CaCl 2提取态Cu、Cd含量分别降低24.9%~64.5%和11.4%~39.3%。因此,淹水条件下施用HAP的水稻土中高含量赤铁矿可以提高Cu和Cd的钝化效果,同时减少磷的有效性。该研究结果对含磷修复材料在我国南方重金属污染水稻土的应用方面具有一定的指导意义。

Hydroxyapatite(HAP)is considered as an amendment for heavy metals contaminated soils,while The iron oxides in the soil have strong binding abilities with phosphate.However,it’s not clear about the effects of iron oxides on the immobilization of heavy metals in soil.The effect of hematite on the immobilization efficiency of copper and cadmium by HAP were investigated through flooding experiments in this study.Results show that the addition of HAP-only and hematite-only increased soil pH and soil solution pH compared with the control.Hematite with high content promoted the reduction of phosphate,dissolved Cu 2+and Cd 2+in the soil solution in the presence of HAP.Meanwhile,soil available phosphorus was reduced by 12.9%-41.0%,and CaCl 2 extractable Cu and Cd were reduced by 24.9%-64.5%and 11.4%-39.3%respectively in HAP plus hematite treatments.Thus,hematite promoted the immobilization of Cu and Cd in the presence of HAP,and decreased the available P in soil under flooding conditions.The results of this study indicated that phosphorus-based materials can be applied to paddy soils in southern China for immobilizing heavy metals.