Vol 40, No 3 (2018)

The paper has investigated destruction of anionic surfactants—sodium dodecylsulfate and dodecylsulfonate in a water medium under the impact of the corona discharge and vacuum ultraviolet radiation (185 nm). We established kinetic characteristics of destruction of the processes being studied. Experimentally it was proved that high values of the concentration of total organic carbon being observed at treatment by plasma and vacuum UV-radiation may be stipulated by determined by recombination of carbonate radicals being formed into organic peroxides or oxalate–anions.

An indicator tube was proposed based on cation exchanger KU-2-8 for sorption-spectroscopic and visual-colorimetric determination of Cr(VI) in waters of different categories. Geometric parameters of the indicator tube were optimized and was found that linearity of the graduation graph for sorption-spectroscopic determination of Cr(VI) is observed within the interval of concentrations 0.01–0.40 μg/cm³ at the weighted amount of the cation–exchanger KU-2-8 0.5 g and the diameter of the column 10 mm. It is shown that the greatest contribution to the resultant color is made by the function of complete color difference, while developed colorimetric scales made it possible to assess the content of Cr(IV) in waters at the MAC level.

Coagulation and sorption properties of hybrid alumosilicic reagent produced by sulfuric acid decomposition of aluminosilicate raw material have been studied. The efficiency of using such reagent in the treatment of different types of model waters is shown. It was established that the use of this reagent enables us to reduce significantly (10 times and more) the residual aluminum concentration in the purified water as compared to the traditional aluminum-containing reagents. In this case, the mechanism of treatment is implemented at the expense of both the chemical interaction of reagent components (chemisorption) and the volume sorption of pollutants on self-organizing mesoporous alumosilicic structures. In addition, this study shows the efficiency of using the alumosilicic reagent as an intensifier of the clarification of waters containing coarse-dispersed and colloid pollutants. It was also established that the introduction of this reagent into Fe(III)-containing water increased the clarification rate more than 20 times, while the high degree of water clarification could be achieved just in 10 min after the reagent introduction.

Mathematical model of the countercurrent extractor based on differential equations has been presented. The model makes it possible to determine average concentrations of components and the extractor height.

The fouling potential of a pilot-scale UASB effluent was determined using different assessment methods (SDI and MFI tests and a mathematical analysis based on a saturation curve model). The UASB reactor was operated at HRT of 4, 8 and 12 h. Although the three methods employed were adequate as a predictive tool for UF membrane fouling, the saturation curve analysis revealed a clearer relationship between the fouling potential of the UASB effluent and the HRT applied. It was found that operating a UASB reactor under short HRT, such as 4 h, could increase membrane fouling in a post-treatment UF module.

The current study was conducted with the aim of examination of changes scope as well as correlation between mercury with zinc and copper in the muscle tissue of tigertooth croaker as one of the most consumed fish in the area (Mahshahr Port) and its comparison with available standards. The obtained results suggested that, total average concentration of Hg, Zn and Cu (mean ± SE) accumulated in the muscle tissue of tigertooth croaker (Otolithes rubber) are respectively equal to 1426 ± 113; 15999 ± 1045 and 2279 ± 94 (ngg^–1) in summer as well as 955 ± 91; 13172893 and 1678 ± 178 (ngg^–1) in winter. Comparison among accumulation rate of elements Hg, Cu and Zn in two seasons showed a significant correlation between two mentioned seasons for Zn and Hg. The correlation result indicates a positive significant relationship between zinc and copper and a descending significant relationship between Hg with Cu and Zn. Concentration of total mercury accumulated in the muscle tissue of tigertooth croaker (Otolithes rubber) within two seasons, summer and winter, are lower than standard limit (500 ngg^–1) defined by WHO while it is higher than standard limit (300 ngg^–1) estimated by USEPA. Due to high concentrations of Hg, the results can be a serious warning for consumption of this fish in Mahshahr region.