摘要
Screening of cost-effective soil amendments is important to develop ＂in situ＂ remediation techniques for cadmium （Cd） contaminated soils. In this study, different soil amendments, including red mud, a by-product of the alumina industry, and acid-treated, nano-treated by nanoparticle milling, nano and acid-treated red muds, zeolite, corn straw, and rape straw, were evaluated to immobilize Cd in two added levels （2 and 5 mg Cd·kg^-1 soil） in a calcareous soil by single and sequential extractions and by cucumber （Cucumis sativus L.） pot experiments. Results indicated that cruciferous rape straw significantly decreased the concentrations of water soluble, extractable Cd in soils, and Cd in cucumber plants, and it was more effective than gramineous corn straw. Also, red mud generally decreased the extractability and bioavailability of Cd added to calcareous soils more effectively than zeolite. Furthermore, the efficiency of red mud could be increased by the treatment of nano-particle milling due to the increase in specific surface area of red mud. It is potential to use rape straw and red mud as soil amendments to develop a cost-effective and efficient ＂in situ＂ rernediation technology for Cd mildly contaminated calcareous soils.
Screening of cost-effective soil amendments is important to develop ＂in situ＂ remediation techniques for cadmium （Cd） contaminated soils. In this study, different soil amendments, including red mud, a by-product of the alumina industry, and acid-treated, nano-treated by nanoparticle milling, nano and acid-treated red muds, zeolite, corn straw, and rape straw, were evaluated to immobilize Cd in two added levels （2 and 5 mg Cd·kg^-1 soil） in a calcareous soil by single and sequential extractions and by cucumber （Cucumis sativus L.） pot experiments. Results indicated that cruciferous rape straw significantly decreased the concentrations of water soluble, extractable Cd in soils, and Cd in cucumber plants, and it was more effective than gramineous corn straw. Also, red mud generally decreased the extractability and bioavailability of Cd added to calcareous soils more effectively than zeolite. Furthermore, the efficiency of red mud could be increased by the treatment of nano-particle milling due to the increase in specific surface area of red mud. It is potential to use rape straw and red mud as soil amendments to develop a cost-effective and efficient ＂in situ＂ rernediation technology for Cd mildly contaminated calcareous soils.
基金
This work was financially supported by Special Fund for Agro-scientific Research in the Public Interest （No. 200903015） 973 Program （No. 2014CB238906） and 863 Program （No. 2013AA06A21r2）. We are also very grateful to the National Natural Science Foundation of China （Grant No. 41201312, 41250110528） for financial support.
