Separation of heavy metal from water samples—The study of the synthesis of complex compounds of heavy metal with dithiocarbamates

ABSTRACT

The toxicity and persistence of heavy metal (HM) ions may cause several problems to marine organisms and human beings. For this reason, it is growing the interest in the chemistry of sulphur donor ligands such as dithiocarbamates (DDTC), due to their applications particularly in analytical chemistry sciences. The aim of this work has been the study of heavy metal complexes with DDTC and their application in separation techniques for the preconcentration and/or removing of heavy metals from the water solutions or the water ecosystems prior to their analysis. The HM-DDTC complexes were prepared and characterized by elemental analysis, FTIR and UV-Vis spectroscopic methods. The elemental analysis and the yield of the synthesis (97.5–99.9%) revealed a good purity of the complexes. High values of complex formation yields of HM-DDTC complexes is an important parameter for quantitatively removing/and or preconcentration of heavy metal ions from water solution even at low concentration of heavy metals. Significant differences founded between the characteristic parameters of UV/Vis (λ_max and ϵ_max) and FTIR absorption spectra of the parent DDTC and HM-DDTC complexes revealed the complex formation. The presence of the peaks at the visible spectral zone is important to M(nd^10-m)-L electron charge transfer of the new complexes. The (C=N) (1450–1500 cm⁻¹) and the un-splitting (C–S) band (950–1002 cm⁻¹) in HM-DDTC FTIR spectra are important to the identification of their bidentate mode (HM[S₂CNC₄H₁₀]₂). The total CHCl₃ extraction of trace level heavy metals from water samples after their complex formation with DDTC is reported in this article.

KEYWORDS:

• CHCl₃ extraction
• dithiocarbamate
• heavy metal
• identification
• synthesis
• trace level