Effect of Thermal Activation Temperature of Nanoscale Phosphate and Silicate on the Morphological Transformation Characteristics of Cd in Heavy Metal Contaminated Soils

Purpose. The problem of heavy metal Cd pollution in the soil is still very serious. widely used treatment measure situ passivation chemical remediation technology. Some studies have shown that single application phosphate or silicate can control cadmium pollution, but few been conducted on effect thermal activation temperature nano and silicate-combined transformation form soil. Materials methods. Cadmium-contaminated was indoor-simulated, after which 2.0% soil-weight dose potassium dihydrogen mixed with serpentine zeolite (potassium phosphate: = 1:2) at different temperatures (0, 350, 550, 700, 850 °C) compared simulated cadmium-contaminated without adding a mixture silicate; content determined by Tessier five-step continuous extraction method incubating for 0, 7, 14, 28, 56 d jars constant-temperature box. Results discussion. Thermal could reduce amount exchangeable to degree; carbonate-bound form, Fe–Mn–oxide-bound organically-bound residual increased. order nanoscale contaminated nPS700-2.0 > nPS550-2.0 nPS850-2.0 nPS350-2.0 nPS0-2.0, nPF700-2.0 nPF550-2.0 nPF850-2.0 nPF350-2.0 nPF0-2.0 (n, P, S, F represent nanometer, KH2PO4, serpentine, zeolite, respectively; T); 700 °C treatments performed better than other treatments, nPF700-2.0. Conclusion. stabilize some extent promote transition from bioavailable state biounavailable state. results showed combined has certain potential pollution.