V. V. Goncharuk

Removal of organic substances from aqueous solutions by reagent enhanced reverse osmosis

Abstract The reagent enhanced reverse osmosis treatment of aqueous solutions containing phenol and its derivatives has been studied. A combination of the reverse osmosis with the oxidation of organic substances by hydrogen peroxide in the presence of FeCl2 salt as a catalyst was shown to lead to the effective removal of phenol and its derivatives from aqueous solutions. The phenol catalytic decomposition was believed to occur not only in the bulk solution but also on the membrane surface. This phenomenon is of particular interest, but additional studies are necessary. In the case of solutions containing lignosulphonates (LS), a combination of the reverse osmosis treatment with the LS oxidation by hydrogen peroxide was found to provide the high degree of solution purification from both organic substances and inorganic salts. Furthermore, it shows a possibility for the recirculation of water.

Nanofiltration in drinking water supply

The paper has presented an analytical review of the state of the art in scientific developments and technological solutions of nanofiltration in drinking water treatment. The article has shown the possibilities of nanofiltration and analyzed reasons restricting its wide-scale use in drinking water supply. It has covered new approaches to the solution of problems related to membrane fouling.

Revealing water’s secrets: deuterium depleted water

BackgroundThe anomalous properties of water have been of great interest for generations of scientists. However the impact of small amount of deuterium content which is always present in water has never been explored before. For the first time the fundamental properties of deuterium depleted (light) water at 4°C and 20°C are here presented.ResultsThe obtained results show the important role of the deuterium in the properties of bulk water. At 4°C the lowest value of the kinematic viscosity (1.46 mm2/s) has been found for 96.5 ppm D/H ratio. The significant deviation in surface tension values has been observed in deuterium depleted water samples at the both temperature regimes. The experimental data provides direct evidence that density, surface tension and viscosity anomalies of water are caused by the presence of variable concentration of deuterium which leads to the formation of water clusters of different size and quantity.ConclusionsThe investigated properties of light water reveal the origin of the water anomalies. The new theoretical model of cluster formation with account of isotope effect is proposed.

Layered double hydroxides intercalated with EDTA as effective sorbents for U(VI) recovery from wastewater

The performance of the synthetic hydrotalcite-like sorbents, initial {[Zn4Al2(OH)12]CO3·nH2O} and heat-treated (Zn4Al2O7) forms and the form intercalated with EDTA and prepared in a nitrogen atmosphere from [Zn4Al2(OH)12]Cl2·nH2O, was evaluated and compared. Increased concentrations of hydrocarbonate and carbonate ions do not noticeably affect the degree of U(VI) recovery from wastewaters with pH 8, which is due to tight binding of U(VI) with EDTA anions in the interlayer space of layered double hydroxides. [Zn4Al2(OH)12]EDTA·nH2O is one of the most effective and cheapest synthetic sorbents for recovering from aqueous media not only cationic but also anionic U(VI) species, which is particularly important. Therefore, the sorbent can be recommended for practical use.

The heterogenic photocatalysis in water treatment processes

The paper has considered the mechanism and main regularities of oxidizing destruction of organic compounds on semi-conductor photocatalysts (predominantly TiO2). The paper discusses the impact of physicochemical factors (concentration and nature of a photocatalyst and a substrate, the pH and medium oxidation-reduction potential, oxidants, etc.) on the decomposition kinetics of pollutants. The paper has analyzed the methods of raising the efficiency of the destruction process by surface and volumetric modification of photocatalysts with noble and other metals, metal oxides, their immobilization on various carriers, etc. It has been shown that the development of highly efficient and low-power-capacity methods of water purification of toxic organic compounds based on heterogenic photocatalytic system in question with the use of oxidants (O2, O3, H2O2, etc.) is a promising area in the ecology of the hydrosphere.

The use of redox potential in water treatment processes

The use of redox potential as a control parameter of wastewater treatment processes for characterizing the natural water condition and estimating the antioxidant properties of drinking water has been investigated.

Photocatalytic membrane reactors for water treatment from organic pollutants

The current status of research in the field of development and application of photocatalytic membrane reactors for water treatment from organic pollutants has been analyzed. The main types of these reactors and the construction techniques and properties of catalytically active membranes were discussed. The combination of photocatalysis and the membrane methods was shown to facilitate the effective removal of different organic substances from water. The factors affecting the water purification efficiency and the prospects of using the hybrid photocatalytic membrane reactors in water treatment processes were also specified.

Removal of Cu(II), Ni(II), and Co(II) from aqueous solutions using layered double hydroxide intercalated with EDTA

A sample of a layered double hydroxide intercalated by EDTA has been synthesized and its chemical formula [Zn4Al2(OH)12](EDTA) · 8H2O was determined. The possibility of applying such sorbent for the extraction of Cu(II), Ni(II), and Co(II) from aqueous solutions was investigated. Comparative investigation of the sorption capacity of carbonate and chelate forms of layered double hydroxides was performed. It is shown that the degree of extraction of metals on sorbent [Zn4Al2(OH)12](EDTA) · 8H2O completely correlates with the stability of complex compounds of these metals in the solution.

Relationship between the Catalytic Behavior of FeZSM-5 Zeolites in Oxidative Degradation of Dyes and the Nature of Their Active Centers

Catalytic activity of FeZSM-5 zeolites in oxidative degradation of Rhodamine 6G and Methyl Orange dyes was studied in relation to the nature, localization, and dispersity of active centers and on the reversibility of the oxidation reduction of iron contained in the zeolites.

Production of sodium hypochlorite in an electrolyser equipped with a ceramic membrane

Abstract The electrochemical synthesis of sodium hypochlorite in a membrane electrolyser equipped with an aluminazirconia ceramic membrane and comprising a titanium anode coated with cobalt oxide has been investigated. The current density, sodium chloride concentration and solution flow velocity in the electrode chambers of the electrolyser have been measured in order to establish how these parameters effect process efficiency. It was found that under optimal conditions the electrical current efficiency reaches 77%. An electrical energy expenditure of 2.4 KWth and a sodium chloride consumption of 3.1 kg per kg sodium hypochlorite produced have been recorded. The anti-corrosion stability of the anode under various experimental conditions was also studied.