Vol 38, No 5 (2016)

The paper has investigated the efficiency of dehydration of two-component dispersion system in its mechanical treatment and additional effect of the electric field. It is shown that at the presence of a gel-like organic component substantially making difficult the process of removing liquid, the degree of dehydration noticeably decreases. For achieving acceptable values of finite moisture in such systems it is necessary to create conditions ensuring electroosmotic transfer of liquid.

The study investigated the efficiency of photocatalytic denitrification of the water medium in the presence of modified titanium dioxide obtained by the sol–gel method. La(Ce)–TiO₂, modified Cu, Ag, Au, Pd and Pt were used as photocatalysts for reducing nitrates and oxidize formic acid. It has been shown that La(Ce)–TiO₂ are active and selective photocatalysts for removal of nitrate–ions from water.

The paper presents results of investigations aimed at optimizing the process of Pb(II) and Cd(II) removal using polyhexamethylene guanidine (PHMG) from aqueous solutions. The formation of compounds of chemisorption-type ions of the above metals with PHMG was established by using the methods of polarography, infrared spectroscopy, and pH-metry. The investigations revealed a positive impact of PHMG on the sedimentation and filtering of the precipitation of Pb(II) and Cd(II) hydroxides.

A sensitive method for the determination of fluoroquinolones in surface waters at trace concentration level is presented. The proposed two-step methodology consists in a solid-phase extraction using C-18 membranes followed measurement of the emission molecular fluorescence spectra over extracted membrane without elution of the analytes. Membrane background signal was removed by the used of chemometrics calculations, in addition chemometrics was as well used for the direct and simultaneous determination of the studied compounds. The method was optimized for the analysis of three fluoroquinolones: enoxacin (ENO), norfloxacin (NOR) and ofloxacin (OFLO). The fluorescence of these compounds increase drastically when they are in the membrane, thus with this method low concentrations are possible to be determined, as the concentration in which these compounds appear in surface water. Limits of detection at the ng•L^–1 level were estimated for ENO, NOR and OFLO.

The article has studied the dynamics of biosorption purification of water of procaine adapted by biomass of active sludge immobilized on activated carbon. The greatest constant of the rate of biodestruction of procaine (0.151 h^–1) suspended by adapted biomass is observed at the concentration of the matter 100 mg/dm³. At biosorption removal of procaine on activated carbon under conditions of stirring the constants of the rates of biodestruction increase two–five times compared with suspended biomass. The adapted biofilm noticeably extend the service life of carbon compared with the spontaneously emerging biofilm at the sake of higher destruction activity.

The degradation degree of oil and complex oil pollutions with heavy metals in water in the presence of microbial Nocardia vaccinii IMB B-7405 surfactants has been studied. The destruction of oil in water (at concentrations of 2.6–6.0 g/dm³) 25–30 days after the treatment with post-fermentative culture liquid (5–10 vol %) containing the surfactants amounted to 76–94%.