Stability of diethyl dithiocarbamate chelates with Cu(II), Zn(II) and Mn(II)

Immobilization has been regarded as one of the most effective technology to eliminate heavy metals contamination. However, the stability of immobilization products and the leakage of immobilized heavy metals impeded its further application. In order to depict the stability of chelating complexes C10H20MnN2S4, C10H20CuN2S4 and C10H20ZnN2S4, DSC-TG analysis, DFT calculation and leakage tests were carried out to reveal the stabilities and the potential leakage risks of immobilized heavy metals when sodium diethyl dithiocarbamate was used as soil amendments. The results indicated that the stability of these three chelating complexes was ranked in the order of C10H20CuN2S4> C10H20ZnN2S4> C10H20MnN2S4. Such precipitations as C10H20MnN2S4, C10H20CuN2S4 and C10H20ZnN2S4 were stable under the neutral and alkaline environment. Meanwhile, leakage of immobilized heavy metals decreased with the increasing leaching pH, whereas time and temperature had no significant impact on the leakage of immobilized heavy metals. And the maximum leakage of immobilized heavy metals was lower than the limited concentration. (C) 2019 Elsevier B.V. All rights reserved.