Tribological properties of a composite mixture based on copper nanoparticles and nanolamellar tungsten disulfide powder have been studied. SEM of copper nanoparticles produced by electrical explosion of wires was analyzed. The tribological tests of pure tungsten disulfide and composite WS2-Cu lubricant are performed. Possible mechanism of copper influence to tribological properties of tungsten disulfide was discussed.

Water objects of Siberia north contain impurities in water in colloid form. The impurities are stable to physical and chemical influence. Search ways of decreasing of natural colloid solutions stability is topical issue. Destruction of colloid particles makes it possible to produce qualitative potable water. In the present work factors influenced on aggregate stability of colloid solutions are represented. It is shown that a disperse phase of natural colloid systems consists of iron and silicium ions and humic organic substances in the ratio 5.6 mg/L : 20 mg/L : 2.2 mg/L, respectively. Calculated electrokinetic potential of colloid solutions is in the range from -23 up to -32 mV. Stability of colloid iron is studied at the presence of CaCl 2 and AlCl 3 electrolits. Coagulation thresholds of CaCl 2 and AlCl 3 are equal to 1.25 mmol/L and 0.0074 mmol/L, respectively. Furthermore, it is shown pH is also influenced on stability of the colloid system. When pH of solution is 4.5 colloid iron system coagulates. This fact allows developing a method of removal of colloid iron by temporal decreasing of pH by using of carbon dioxide. This method is ecologically safe and allows simplifying technology of water-preparation due to exception of the thin filtration which is used for removal colloid particals. The pH renewal is spontaneous process which is going while carbonization is going. Thermodynamic calculations of reactions describing the destruction mechanism of colloid iron are represented.

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The paper reports on experimental modeling of the colloid system composition in natural groundwater. Iron hydroxide is found to be the main component of natural colloid systems. It is shown that silicon compounds and dissolved organic substances (DOS) stabilize iron hydroxide (III), forming a stable colloid system, and preclude coagulation. The presented results suggest that CaCl2 and AlCl3 electrolytes affect the coagulation stability of synthesized model colloid solutions.

Pulsed electric discharge has been used for the removal of iron colloid substances from aqueous solutions. The residual concentration of organic substances in aqueous solution depends on the pulse repetition rate. The maximum decrease in organic substances concentration was observed at the pulse repetition rate of 800 pps. Comparison of the results obtained for iron colloid solutions containing humic substances and solutions of humic subtances with no colloids shows that the highest removal efficiency of organic substances was obtained when no iron and silicon ions were present in the solution. The results of our experiments suggest that pulsed electric discharge treatment for the removal of organic substances from natural waters is more efficient at an after-treatment stage, after precipitation of colloid substances.