Immobilization of cadmium contaminated soils using sepiolite and its compound materials
海泡石及其复配材料钝化修复镉污染土壤

An outdoor pot-culture experiment was carried out to study the effects of different sepiolite treatments on immobilization of cadmium (Cd) contaminated soils collected from Daye County, Hubei Province. The effects of sepiolite, acid-modified sepiolite and their compound treatments with lime and phosphate on plant growth and Cd accumulation in Brassica chinensis and pH value and available Cd concentration of polluted soils were determined. Different sepiolite treatments could effectively increase dry biomass of shoots and roots, with maximal increases of 1.03 and 1.43 folds, respectively. And the yield increasing effect of compound treatments and single treatment of modified sepiolite was better than that of single treatment of sepiolite. Different sepiolite treatments could significantly reduce Cd concentration in shoots and roots, with maximal reductions of 66.40% and 22.68%, respectively. The compound amendment treatments appeared more efficient than the single amendment treatments in reducing Cd uptake of Brassica chinensis, and the optimum dosage of amendments was 6%. The compound amendment treatments and single treatment of sepiolite could markedly increase pH values of soils. Different sepiolite treatments could significantly decrease available Cd concentration of soils, and the compound amendment treatments appeared more efficient than the single amendment treatments in reducing Cd availability of soils. In summary, the compound treatment of sepiolite and phosphate is the most effective treatment for immobilization of Cd contaminated soils.