Hasan Cesur

Determination of copper, nickel and cadmium by faas after preconcentration with zinc-piperazinedithiocarbamate loaded on activated carbon by solid-phase extraction

ABSTRACT A method was developed for the preconcentration of copper, nickel and cadmium in water samples, prior to their determination by FAAS, using the Zn-piperazinedithiocarbamate complex (ZnPDC) loaded on activated carbon. In this method, Cu, Ni and Cd in liquid phase quantitatively replaced zinc on a ZnPDC-activated carbon solid phase. Afterwards, the metals on the solid phase were easily eluted by Hg (II) solution into aqueous phase, and were measured by FAAS. The optimum experimental parameters such as pH, sample volume, and effect of matrix ions for the preconcentration of the metals were investigated. The range of linearity 0-6, 0-5, 0-3 μgml−1, correlation coefficient 0.998, 0.996, 0.999, detection limits 15.7, 23.5, 11.8 ngml−1 and determination limits 136, 179, 98 ngml−1 in final Hg(II) solution were obtained for Cu, Ni and Cd, respectively. The proposed method has been employed for the determination of Cu, Ni and Cd in various standard metal alloys and natural water samples.

SYNTHESIS, CHARACTERIZATION, AND SPECTRAL AND THERMAL STUDIES OF SOME DIVALENT TRANSITION METAL COMPLEXES OF BENZYLPIPERAZINE DITHIOCARBAMATE

Potassium benzylpiperazine dithiocarbamate (KBPDTC) and its complexes with Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) have been synthesized and characterized. On the basis of elemental analyses, magnetic moments and spectral data, the monoanionic BPDTC ligand coordinates to the metal ions via both sulfur atoms of the -NCS2 group, acting as a bidentate ligand. The Ni(II) complex has a square-planar coordination geometry, while the other complexes are suggested to exhibit a square-pyramidal coordination environment. The thermal reactivity of KBPDTC.H2O and its metal complexes has been studied by means of DTA and TG techniques. Thermoanalytical data show that decomposition of the metal complexes of KBPDTC under nitrogen gives the corresponding metal thiocyanates as stable solid intermediates.

Metal Complexes of Phenylpiperazine‐Based Dithiocarbamate Ligands. Synthesis, Characterization, Spectroscopic, Thermal, and Antimicrobial Activity Studies

Potassium salts of phenylpiperazine (Phpzdtc), fluorophenylpiperazine (F‐Phpzdtc) and nitrophenylpiperazine (N‐Phpzdtc) dithiocarbamates and their manganese(II), iron(II), cobalt(II), nickel(II), copper(II) and zinc(II) complexes have been synthesized and characterized by elemental analyses, IR, UV‐VIS, magnetic moment measurements and thermal analysis techniques. On the basis of experimental data, the dithiocarbamates (dtcs) have been observed to coordinate to the metal ions via both sulphur atoms of the –NCS2 group forming metal complexes with a metal to ligand ratio of 1:2. The thermal reactivity and antimicrobial activity of the ligands and their metal complexes were also studied. The decomposition of the metal complexes resulted in the formation of the corresponding metal thiocyanates or cyanates as stable intermediates. Phpzdtc was found to be microbiologically more active than its nitro and fluoro derivatives and biological activity of the dtc ligands either remained unaltered or decreased on complexation with metal ions.

A kinetic study on cadmium adsorption from aqueous solutions by pre-conditioned phosphogypsum

AbstractIn the present study, the effect of contact time, adsorbent dosage, and initial cadmium concentration on the adsorption of Cd(II) ions from aqueous solutions by pre-conditioned phosphogypsum was investigated. The kinetics of adsorption was studied and, pseudo-first-order, pseudo-second-order, and Elovich models were used to fit the experimental data, which was obtained from batch experiments. The kinetic adsorption data fitted well into the second-order kinetic model. Adsorption mechanism was explained with the intraparticle diffusion and Boyd kinetic models.