Leaching and stabilizing characteristics of copper diethyl dithiocarbamate in an acetic acid solution

The leaching and stabilizing characteristics of synthetic copper diethyl dithiocarbamate (Cu-DDTC) under 1 N acetic acid solution were characterized using semi-dynamic leaching test (SDLT), ultraviolet-visible spectrophotome- ter (UV-visible), X-ray diffractometer (XRD), fourier transform infrared spectrophotometer (FTIR), and scanning electron microscopy (SEM) techniques- . The analyses of leached species of leaching solution by SDLT and UV-visible indicated that the degree of degradation of various elements from the Cu-DDTC complex could be classified as: N(25%)>S(20%)>Cu(0.7%) and no dithiocarbamate species in the liquid phase were detected. The copper species of insoluble Cu-DDTC complexes were much more stable than those of copper solidification in cementitious matrix. The investigati- on of crystallinity showed that there were two unidentifiable peaks present in the XRD pattern of the leached Cu-DDTC complex that might be attributed to new chemical interactions. The spectra obtained by FTIR analyses obviously showed that the major functional groups, such as C-N, S-C-S, C=S, Cu-S, and C-H groups, were both present in the unleached and leached Cu-DDTC complex. Microstructural analyses by SEM revealed that the unleached and leached Cu-DDTC complexes had the same morphologies, but the grain size of the leached Cu-DDTC complex is much larger and compact than that of the unleached complex. Thus, it was suggested that the leaching and stabilizing characteristics of the insoluble Cu-DDTC complexes consisted of the dissolution and decomposition of Cu-DDTC and the chelating reaction between copper and NDDTC.