Vol 40, No 2 (2018)

Comparison of the efficiency of photocatalytic oxidation of aqueous solution of fulvic acids (TOC₀—15.9–17.1 mg/dm³, pH0 6 ± 0.1) by oxygen of the air, hydrogen peroxide and ozone in a reactor containing a wide-porous ceramic block with immobilized TiO₂ with the variation of the concentration of H₂O₂, feed rate of O₃ and temperature showed advantages of photocatalytic ozonization and expediency of its use for deep destruction of natural organic substances in water. The maximum degree of destruction in photocatalytic systems O₂/TiO₂/UV, H₂O₂/TiO₂/UV and O₃/TiO₂/UV constituted respectively 41, 73 and 90% for TOC for 5, 4 and 3 h.

The article shows the efficient use of natural apatite ore in purification of mining industrial wastewaters from heavy metal ions. The determination of adsorption constants, calculation of thermodynamic parameters at various pH of the medium were carried out. It was established that the sorbent based on apatite ore may be used in ecological and technological aims in water conditioning and water treatment.

A new sensitive and selective method including solid phase preconcentration and next determination of trace amounts of Cd(II) by flame atomic absorption spectroscopy in water samples was developed. Cadion was coated on carbon active powder and used as a solid phase sorbent. Detection limit for extraction of 2000 mL aqueous solution is 0.35 μg·L^–1. The relative standard deviations for concentrations 2.5 and 15 μg·L^–1 with preconcentration factor 200, 0.4 and 0.2% (n = 3) were obtained, respectively. The calibration curve is linear in the range of 1.5–15 μg·L^–1. The accuracy of the method was evaluated and confirmed by the inductively coupled plasma atomic emission spectrometric analysis. Method was applied for the determination of cadmium in well water.

Modification of ceramic membranes was conducted with silica, obtained from liquid glass, and pyrocarbon from carbonized polyisocyanate and sucrose at 800°C. Water from Ca²⁺ and direct scarlet dye was purified by a pressure-driven method at 0.7 and 1.1–1.2 MPa. The retention coefficient of Ca²⁺ and specific productivity of the modified membranes depending on filtration time decreased respectively from 63 to 8% and from 150 to 4.7 dm3/(m².h). For direct scarlet dye, the retention factor constitutes 99.0 and 99.9% at the specific productivity respectively 27 and 1.8 dm3(m².h).

Electrokinetic removal of hydrophobic organic compounds from soil systems of various compositions making it possible to avoid an ingress of toxicants into groundwater has been investigated. Solubilization of impurities was ensured by using aqueous solutions of nonionic surfactants belonging to the group of oxyethylated alkylphenols. The distribution curves of residual impurity content were obtained after the termination of electric treatment of soils following the passage of different volumes of electroosmotic solutions containing surfactants. The specified curves allow us to predict the possibility of achieving the required treatment efficiency.

To attain better removal efficiency and higher toxic resistance, the alginate was used to immobilize Phanerochaete chrysosporium BKM-F-1767 in this study. And according to the characteristics of tannery wastewater, inhibitory effect of Cr(III) to the decolorization was investigated and adsorption kinetics of Cr(III) by the immobilized P. chrysosporium had been established. Furthermore, the Acid Violet 7 and Basic Fuchsin contributed as the experimental dyes in the paper, the removal studies were performed at an initial pH of 4.5. The combined effects of Cr and dyes on the simultaneous removal properties were determined in a batch system at different levels of Cr and dyes. Moreover, the dose-response relationship and a kinetic equation describing the simultaneous removal properties had been established. The results have proved that the immobilized P. chrysosporium has the ability to treat the tannery wastewater.

The disinfection of recycling polymer based demijohns using in drinking water industry was targeted by using chlorine dioxide containing solutions. 1.5 L volume polyethylene terephthalate bottle was chosen as container to characterize the polymeric demijohn. Disinfection of the intentionally contaminated containers was performed with the 0.3–2 ppm range ClO₂ containing washing solutions which were prepared from the stock solution. Active matter concentration, washing time and the washing number were studied in gradient. Disinfection efficacy of ClO₂ on Escherichia coli ATCC 25922 and Enterococcus faecalis ATCC 29212 was investigated. The bacteria were chosen according to “Implementing Regulation on Water Intended for Human Consumption”. Viable bacterial cell was enumerated by membrane filtration method. The results were established as colony forming unit. The increasing of the concentration decreased the washing time is another determined result.