Vol 41, No 2 (2019)

The article has studied adsorption of ions of heavy metals of microporous carbon Aquacarb and its mesoporous analog obtained by modification of the surface of the latter by the solution of Ca(Ac)₂ followed by activation with water vapor at 800°C. It is shown that when using mesoporous analogs adsorption of Cu²⁺, Co²⁺ and Zn²⁺ dramatically increases.

This paper reports the use of unfunctionalized and phenylalanine functionalized clays as an alternative cost effective, environmental friendly and efficient sorbent for the removal of Mn and Fe from polluted drinking water sources in Lesotho. The Mn and Fe metals were adsorbed on two different clays (clay A—a black clay and clay B—a yellow clay) collected from Ha-Teko in Maseru (clay A) and Phoqoane in Mafeteng district (clay B). Comprehensive batch test studies were performed to assess the effect of pH, stirring time and initial concentration of Mn and Fe. The adsorption of the metals was greater at higher pH and equilibrium was reached at pH 8 after 30 min of stirring. The phenylalanine functionalized clays displayed improved adsorption efficiency of up 100% (Fe adsorption using clay A in 30 min) while the unfunctionalized clays gave relatively low adsorption of up to 70% (Fe and Mn adsorption using clay A). The clays, which are present in abundance in Lesotho, can be effectively used for the removal of Fe and Mn from drinking water sources.

The article has studied the removal of U(VI) chelatoforming sorbent based on anhydride with styrene chemically modified by dithizone. It was established that uranium is sorbed to its maximum at pH 5 (ammonia-acetate buffer) and concentration 1428 mg/dm³. Statistical sorption capacity—1249 mg/g. It was cleared out that ionic force up to 0.6 did not affect sorption and its consecutive increase at first gradually and then sharply decrease sorption. It is established that when using different mineral acids (HCIO₄, H₂SO₄, HNO₃, HCI) maximum desorption is observed in perchloric acid. The technique for concentration of U(VI) in sea water has been developed including sorption, elution and definition in the desorption solution.

The efficiency of the application of electrochemically generated Na₂FeO₄, for the purpose of the elimination of Th(IV) ions from water samples as coagulating agent was investigated. Th is a radioactive element often used as a fuel for nuclear reactors. The continuous exposure to Th(IV) may cause cancer of the pancreas, bone or lung. Analyzed natural water samples spiked with Th(IV) were treated with solution of ferrates (VI) under recommended conditions of electrochemically synthesized ferrates solution and Th(IV) was quantified by established kinetic method. Removal of Th(IV) ions by ferrates (VI) was successfully confirmed by comparison of the concentration of Th(IV) before and after ferrates (VI) treatment of spiked analyzed water samples. A simple kinetic-spectrophotometric method was successfully applied to determine Th(IV) concentration, indicating the decrease in the concentration of Th(IV) in water samples applying ferrate (VI).

Some emerging pollutants in wastewater sources, urban and hospital, of Mexico City was determined. Solid phase extraction of the selected pollutants from the different matrices and an high performance liquid chromatography analysis technique for their quantification were implemented. Results showed that hospital wastewater contained higher organic matter concentration than urban wastewater. Analgesics and antibiotics were found in all samples. High concentrations of paracetamol, naproxen, sulfamethoxazole and β-estradiol were found in hospital wastewater, ranging from 9 to 27 µg·L⁻¹, showing that, in general, pharmaceutical concentrations in hospital wastewater were higher than those found in urban and in the influent of the wastewater treatment plant, where concentration ranged from 0.18 to 4.79 µg·L⁻¹. In the effluent of wastewater treatment only the antibiotics were found, sulfamethoxazole, trimethroprim and ofloxacin at 0.63; 0.55 and 0.29 µg·L⁻¹. It is the first work reporting the presence of pharmaceutical compounds from a hospital and wastewater urban from Mexico City.

The expediency of mastering the systems for combined desalination of sea water based on the reverse osmosis method and thermal distillation method using the exhaust heat of power plants has been substantiated. The technology of Mg-Na-cation-exchange decalcification is proposed for preventing the sulfate scale formation. This technology provides for the regeneration of cation-exchange resin by the mixture of magnesium and sodium salts contained in the purge solution at the stage of thermal distillation of reverse osmosis concentrate. It has been shown that the conversion of the softened Caspian and Black Sea waters by using the combined desalination can be raised to the levels of 87.4 and 81.9%, respectively. The performed investigations were of the computational and analytical character.

This study deals with the possibility of inactivation of micromycetes under the influence of electric field with intensity 100–185 V/cm and the temperature increased to 45–65°C. The regularities of the filtration process of Candida albicans micromycetes on the bed of AB-17 anion-exchange granules placed into electric field have been established. The range of field intensity and flow rates of the filtered liquid ensuring the stable purification degree 99–100% are determined.

Presented is the first developed complex bioengineering facility, which incorporates a natural waterside and artificial immersed wetlands. The action of the facility is directed at water detoxication and bottom sediments using small rivers as an example at the sake of plants of hydrophytes and gidatophytes. Presented are results of introducing the given technology in one of small watercourses of Kyiv. It is shown that realization of the proposed biotechnology ensures a positive water protection effect because in the site of facility location water quality is improved, its self purification capacity is raised and toxicity decreases.