Modification and characterization of cellulose cotton fibers for fast extraction of some precious metal ions.

In this work, native cellulose cotton fibers were first modified through graft copolymerization of polyacrylonitrile (PAN) and then by insertion of phenyl thiosemicarbazide moieties to finally produce C-PTS chelating fibers, which were fully characterized using various instrumental techniques such as SEM, FTIR, EDX and XRD spectra. The obtained C-PTS were employed in removal and extraction of Au(3+), Pd(2+) and Ag(+) precious metal ions from their aqueous solutions using batch experiments. The kinetic studies showed that the pseudo-second-order model exhibited the best fit for the experimental data. In addition, the adsorption isotherm studies indicated that the adsorption follows the Langmuir model and the maximum adsorption capacities for Au(3+), Pd(2+) and Ag(+) were 198.31, 87.43 and 71.14 mg/g respectively.

Selective flotation-separation and spectrophotometric determination of cadmium using phenanthraquinone monophenythiosemicarbazone.

A simple, selective and sensitive procedure is described for the preconcentration by flotation followed by spectrophotometric determination of trace amounts of Cd(II). Cadmium forms an intense red 1:2 complex with phenanthraquinone monophenylthiosemicarbazone (PPT) at pH > or = 6. The colored Cd-PPT complex was floated quantitatively with oleic acid (HOL) surfactant at pH 6.5, exhibiting maximum absorbance at 520 nm and having a molar absorptivity of 2.4 x 10(5) L mol(-1) cm(-1). The stability constant of the formed complex is 1.5 x 10(12); log K = 12.2. Beer's law was obeyed over the concentration range 0.01-0.34 mg/L. The Sandell sensitivity and relative standard deviation are 0.4 ng/cm2 and 2.6%, respectively. The results obtained spectrophotometrically were compared to those obtained by AAS analysis. The analytical parameters affecting flotation and hence determination have been thoroughly investigated. The proposed procedure was successfully applied to the determination of Cd(II) traces in certified and real human hair samples as well as in natural waters. The structure of the complex formed and the mechanism of flotation were proposed.

Selective flotation-spectrophotometric determination of trace copper(II) in natural waters, human blood and drug samples using phenanthraquinone monophenylthiosemicarbazone.

Copper(II) forms 1:1 and 1:2 intense red complexes with phenanthraquinone monophenylthiosemicarbazone (PPT) at pH 3-3.5 and > or =6.5, respectively. These complexes exhibit maximal absorbance at 545 and 517 nm, the molar absorptivity being 2.3 x 10(4) and 4.8 x 10(4) l mol(-1) cm(-1), respectively. However, the 1:1 complex was quantitatively floated with oleic acid (HOL) surfactant in the pH range 4.5-5.5, providing a highly selective and sensitive procedure for the spectrophotometric determination of CuII. The molar absorptivity of the floated Cu-PPT complex was 1.5 x 10(5) l mol)(-1) cm(-1). Beer's law was obeyed over the range 3-400 ppb at 545 nm. The analytical parameters affecting the flotation process and hence the determination of copper traces were reported. Also, the structure of the isolated solid complex and the mechanism of flotation were suggested. Moreover, the procedure was successfully applied to the analysis of CuII in natural waters, serum blood and some drug samples.

Preconcentration and separation of total mercury in environmental samples using chemically modified chloromethylated polystyrene-PAN (ion-exchanger) and its determination by cold vapour atomic absorption spectrometry.

The use of chemically modified chloromethylated polystyrene-PAN, CMPS-PAN (ion-exchanger) for the preconcentration and separation of total mercury after digestion in preparation for determination by cold vapour atomic absorption spectrometry (CVAAS) was described. The effects on the percentage of recovered mercury by mass change of ion-exchanger, stirring time, pH of the solution samples and eluent concentration were studied. The distribution coefficient K(d) is 10(6.6) ml g(-1). The interfering effects of some foreign ions were described. The metal complex formed between CMPS-PAN ion-exchanger and mercury was characterized by IR spectroscopy, pH-metric titration and thermal analysis. The method is simple and rapidly applicable for the determination of total mercury (ng ml(-1)) in natural water, milk and urine.