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 spectrophotometer (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 investigation 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. Microstrctural 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.