Vol 38, No 2 (2016)

The paper has investigated the process of measuring power illumination for vacuum ultraviolet radiation by means of the solution of potassium iodide as a photochemical actinometer. We have investigated the formation of triiodide–ion when radiated the solution of light with wavelength 185 nm. It has been shown that obtaining hydroxyl radicals OH^– at this wavelength is determined by the formation of I₃^–. The quantum yield of the process constitutes 0.165. Measuring the concentration of the obtained I₃^– we determined power illumination of a quartz lamp DRB-20 (wavelength 185 nm), which constitutes 49.2 × 10^–9 E/s.

A sorbent based on Zn/Al-hydrotalcite intercalated by hexacyanoferrate (II)-ions is proposed for ¹³⁷Cs concentration and its further radiometric determination in natural waters. Parameters for the optimal sorptive extraction of radiocesium from waters under static conditions and direct radiometric measurements have been determined. The use of ferrocyanide sorbent is shown to provide a good potential in analytical schemes of ¹³⁷Cs concentration from waters with high salt background.

The article has investigated main commodity synthetic polymers (polyethylene terephthalate(PETP), polyethylene (PE) and polystyrene (PS) and their blends designed for adsorption of lead ions from wastewaters. Blends were prepared by extrusion from the melt at PS concentration from 5 to 20 fraction of total mass, %. The time of attaining equilibrium at adsorption of lead ions on the polymer surface has been found. The obtained data indicate that polymers in question were more efficient compared with others, which investigated for assessing their adsorption ability with respect to lead ions. Results of equilibrium isothermal adsorption of lead ions on the mixed PETP/PS system point out that at an increase of percent content of PS in the blend a substantial increase of adsorbed lead is achieved per unit weight of polymer adsorbent. This correlates with the type and dimensions of interface morphology of blends.

Photometric technique has been developed for determination of bromide ions in waters; the technique is based on oxidation in an aqueous solution of bromide to bromine by chloramine T, concentration of bromine–derivative fuchsine basic on membrane filters and measurement of lightness of obtained colored concentrates in a thin layer by means of reflection colorimetry. The detection limit of bromide–ions constitutes 10 μg/dm³, the linearity of the calibration curve ranges from 10 to 1000 μg/dm³. The excess of chloramines T does not interfere with determination, which simplifies and reduces the analysis. The proposed technique is more sensitive, fast and simple in execution than existing standard techniques. It makes it possible to control the content of bromide–ions in waters both at the level and lower than MAC and may be used in field conditions at the site of sampling

In this article, the results of three years monitoring of selected pharmaceuticals (diclofenac, ibuprofen, carbamazepine, salicylic acid, clofibric acid) in the wastewaters of the Czech Republic are presented. The monitoring was performed on selected Wastewater Treatment Plants (WWTP) with various treatment technology and designed capacity. The concentrations and treatment efficiency of these substances were observed in various profiles of each WWTP, including influent, mechanical pretreatment, biological treatment, effluent. The main processes of removing selected pharmaceuticals during wastewater treatment are discussed. These results are used for design wastewater treatment technology with improved treatment efficiency of these substances.

The article has investigated the removal of water borne pathogens using dielectrophoresis (DEP) filter which is energized by varying the frequency of the applied potential from 10 kHz to 2 MHz with different voltage levels of 5; 10; 15 and 20 V. Separate experiments are conducted in artificially contaminated water samples with Escherichia coli, Staphylococcus aureus and Vibrio cholerae up to 2 h. The impact of signal frequency and voltages on DEP based water treatment system has been analyzed statistically. Results have demonstrated that an AC signal of 20 V with frequency range of 500 kHz to 2 MHz is suitable to remove the tested bacterial population and the rate of removal of E. coli is the highest with a dielectrophoretic filtration efficiency of 77.1%.