Vol 40, No 6 (2018)

Electrofiltration of the particles of cation exchanger KU-2-8 and anion exchanger AV-17 pounded to the size (1–4) μm through a granulated cation exchanger KU-2-8 was investigated. The interval of electric field strength and flow velocities of a filtered liquid, which achieves a stable 99% degree of decontamination, is determined. Features of the impact of polarized dispersion particles on their movement in the electric field, aggregation and formation of the sediment on the granules are analyzed. It is shown that the movement of these particles to the granules is done mainly owing to dipolophoresis and the formation of particles aggreagates which form the sediment is caused by the dipole-dipole interaction.

The raw and oxidized multi-walled carbon nanotubes mixed with H₂SO₄/HNO₃ were used to remove PNA from aqueous solutions. Heat recovery using nanotubes was performed in two stages. The effective factors on PNA removal were studied. The adsorption isotherms and kinetic reactions were determined. Optimal conditions for a real solution of petrochemical wastewater were performed to evaluate the PNA adsorption. The maximum removal efficiencies of PNA by raw and oxidized carbon nanotubes was obtained at optimal conditions. The equilibrium adsorption capacity is dependent on the amount of adsorbent and also the initial concentration of material that will be adsorbed. The process of adsorption followed second order kinetic and Langmuir isotherm. This is a good adsorbent in PNA removal from aqueous solution. It also can recover in several stages.

A technique for measuring the selenium microconcentrations in different drinking waters using the pulse inverse chronopotentiometry method with sufficient reproducibility and accuracy based on the metrological certification criteria has been developed. It is shown that this method is expedient for monitoring the state of water sources in the environment.

The article presents research results on the rates of dissolving oxygen of the air in water during its treatment in an aerator–oxidizer. Relationships between the oxygen dissolution rates and parameters of treatment and design of the aerator–oxidizer are esteblished.

The photodegradation and detoxification of 2-chlorophenol (2-CP) in TiO₂ suspensions were studied using monochromatic UV-lamp. The effect of pH on the photodegradation of 2-CP was investigated. Removal of 98% of initial 2-CP was achieved within 210 under optimum concentration of 2-CP (60 mg/L) and TiO₂ (80 mg/L). The apparent first-order rate constant k_app of 2-CP is estimated to be 0.0043 min^–1 at pH 4, while a 3-fold increase in k_app was observed at pH 9. Phytotoxicity effects of treated 2-CP on seed germination, root elongation and plant growth of tomato (Lycopersicon esculentum) and turnip (Brassica rapa) seeds were also carried out with the aim of water reuse and environment protection. No statistically differences have been also found to exist for seed germination of tomato and turnip between deionized water (control) and phototreated 2-CP solution, indicating a significant removal of the overall toxicity. In the 10th day of germination, the average root elongation increases at 210 min of photocatalytic degradation yielding 7.1 ± 0.9 and 5.6 ± 0.66 cm for turnip and tomato seeds, respectively. Turnip plants irrigated with the phototreated 2-CP solution grow in a similar manner as the plant irrigated with the tap water. The phototreated 2-CP can be used in the irrigation of agriculture garden but only after further treatment.

Date palm seeds (Phoenix dactylifera L.) were investigated as a biosorbent for removal of Pb(II) ions, which has a toxic effect on the environment. A batch sorption process was applied. Optimization of Pb(II) biosorption ontodate palm seedswas successfully carried out using response surface methodology. The effects of process variables, such as pH, initial Pb(II) concentration and biosorbent mass, on the adsorbed amount of Pb(II) were investigated using Box-Behnken design. The fitted results were found to be in good agreement with the results obtained by performing the experiments. The second-order response function showed that pH and initial Pb(II) concentration had positive effects, while biosorbent mass showed a negative effect. Initial Pb(II) concentration was the most significant factors that affected the removal of Pb(II) under the studied conditions. The maximum uptake of Pb(II) predicted by optimization plots was 24.07 mg/g at pH 5 initial Pb(II) concentration 100 mg/L and biosorbent mass 0.100 g.

The monitoring of potable artesian waters of the city of Kyiv for bromide, bromate, iodide, and iodate ions as well as of drinking bottled water for bromides and bromates has been carried out. Bromate, iodide and iodate ions were monitored by the established methods and bromide ions—by the developed method. The stability of the chemical composition of artesian waters of the same horizon is noted. On the other hand, the concentration of bromides and iodides varied 3–4 times in pump-rooms feeding on a mixture of waters from aquifers. For waters containing high concentrations of bromides and iodides, ozonation is counter indicated due to hazard of the formation of carcinogenic bromates and iodates. A conclusion was made that it is more expedient to use carbon dioxide treatment for canning and disinfection of such waters.