Commercial macroporous poly(4-vinylpyridine-co-divinylbenzene) [P4VPD], known as REILLEX-425 was characterized by mercury porosimetry, nitrogen physisorption, Fourier transformed infrared (FTIR) spectroscopy and elemental analysis. Sorption rates of P4VPD for Cu(II), Co(II) and Cr(VI) ions were determined in static non-competitive experiments, at room temperature (298 K). Rapid sorption was observed, especially for Co(II), with half time, t1/2, of 1.5 min and high experimental maximal capacity, Qmax, of 3.08 mmol g-1. Four kinetic models (pseudo-first and pseudo-second order model, intraparticle diffusion and Boyd model) were used for analyzing metal sorption by P4VPD. Metal ions sorption is well represented by the pseudo-second-order model, with definite influence of pore and film diffusion on sorption rates. [Projekat Ministarstva nauke Republike Srbije, br. III43009

A multifactor optimization strategy was utilized to predict the isocratic HPLC separation of nine phenols. The retention behavior was studied as a function of changing eluent (methanol ? acetic acid) composition. The predicted and measured retentions are in rather good agreement. To locate the optimum in the factor space, the normalized resolution product criterion was applied. In virtually every case, the resolution is limited by the separation of the 2-chlorophenol and 2,4-dinitrophenol pair.

Resorcinol-formaldehyde carbon cryogel has been prepared, characterized and used for the removal of commonly used herbicide clopyralid from the aqueous solutions under varying experimental conditions. Carbon has shown a relatively high specific surface area, significant mesoporosity and an amorphous structure. A set of the following isotherm models has been used to interpret the equilibrium data: Langmuir, Freundlich, Temkin, Dubinin-Radushkevich, Jovanovic, Hurkins-Jura, and Helsey model. Several models have fitted well although the calculated values for qmax poorly correlate with the data obtained experimentally. The kinetic models of the pseudo-first and pseudo-second-order, the models of Elovich, Bangham and the intraparticle diffusion model have been used for fitting the kinetic data. The rate of the process is fast in the beginning while adsorption equilibrium is attained not until 24 hours. Adsorption was found to be pH dependent and favored in acidic solutions.

Among radionuclides in the soil deposited after Chernobyl accident, 137Cs poses considerable environmental and radiological problems because of its relatively long half-life (30.17 y), its abundance in the fallout, high mobility and similarity to potassium as the major plant nutrient. In this study the samples of undisturbed surface soil (n=250) were taken from 70 regions in Belgrade, during 2006-2010. The specific activities of 137Cs were measured by gamma-ray spectrometry. Based on obtained results external effective dose rates were calculated according to the internationally accepted activity to dose rate conversion equations. The specific activities of 137Cs were geographically mapped. The presence of 137Cs has been detected in all soil samples, with high variability of its specific activity, ranging from 3 Bq kg-1 to 87 Bq kg-1. The mean specific activity of 137Cs was 23 Bq kg-1 and the corresponding absorbed dose was 1.5 nSv h-1. The observed range reflects the inhomogeneity of the deposition process following the Chernobyl accident. It could also be attributed to topographic differences and spatial differences in physicochemical and biological soil properties, soil type and vegetation cover. The results of the present study could be valuable database for future estimations of the impact of radioactive pollution.

The parameters for the development of a chromatographic (HPLC) method and its validation are discused in the paper. Chromatographic analysis involves a multi-step procedure consisting of sample collection, pretreatment instrumental measurements and data processing. Emphasize was placed on the instrumental part of the analysis presuming that the contributions of the other variables were minor. The roles of precision, accuracy, detection limit, quantification limit, specificity, selectivity, range, linearity and robustness, as well as system suitability in the analytical application of chromatography were described. Recommendations for the validation of these parameters according to ICH and FDA guidelines are given. The criteria of validation described above can be almost completely applied to other instrumental chromatographic techniques such as GC, GC-MS, HPTLC, etc