Journal of Ecology and Rural Environment ›› 2020, Vol. 36 ›› Issue (6): 796-802.doi: 10.19741/j.issn.1673-4831.2019.0916

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

WU Qiu-gang1,2, WANG Yan-jun1, ZHAO Heng1, YANG Liu1, MENG Rui-yan1, HE Jian-guo1   

  1. 1. Jiangsu Institute of Geological and Mineral Design, Xuzhou 221006, China;
    2. School of Earth and Environment, Anhui University of Science and Technology, Huainan 232001, China
  • Received:2019-11-13 Online:2020-06-25 Published:2020-06-22

Abstract: 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 Cu2+ and Cd2+ in the soil solution in the presence of HAP. Meanwhile, soil available phosphorus was reduced by 12.9%-41.0%, and CaCl2 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.

Key words: flooding, hematite, heavy metal, hydroxyapatite, immobilization

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