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EN
In this work, the processes of purification of oily waters using magnetites were investigated: magnetite synthesized according to the classical method and magnetites modified with hydrophobizing agents (sulfonol or alkylimidazolin). It was shown that magnetite modified with alkylimidazolin in doses of 50–200 mg/dm3 provides a high degree of oil removal from waters of various mineralization. The degree of water purification reaches 97.5–99.8%. Sulfonol-modified magnetite shows greater efficiency than conventional magnetite only at high concentrations (200 mg/dm3) and only in fresh water. Three hours is enough to ensure the maximum degree of purification of water-oil solutions. Changing the amount of hydrophobizing agent (alkylimidazolin) during the synthesis of magnetite reduces the effect of pH on the purification of both fresh and mineralized waters.
EN
The article describes the modern problems of formation and purification of marine oil-containing waters. The efficiency of using electrocoagulation to remove oil from water-oil emulsions of different mineralization using aluminum and iron anodes was studied. Treatment of water-oil solutions with an oil content of 100 mg/dm3 by electrocoagulation in a single-chamber electrolyzer provides 98–99% oil removal using these electrodes at an anode current density of 0.57–2.11 A/dm2 for highly mineralized waters and 0.34 A/dm2 for freshwater treatment during the first 15 minutes provides a reduction in oil concentration from 100 mg/dm3 to values at the level of 1.55–2.93 mg/dm3. When the water treatment time is extended to 45 minutes, greater efficiency in highly mineralized waters is provided by the aluminum anode.
EN
Processes of water purification from phosphates using a low-pressure reverse osmosis membrane were studied. It was shown that the concentration of phosphates in the permeate largely depends on their initial concentration in the water and increases along with the degree of permeate selection. It was established that when using the Filmtec TW3–1812–50 membrane for phosphate concentrations up to 20 mg/dm3, their concentration in the permeate does not exceed 2.5 mg/dm3 with a degree of permeate selection up to 90% when cleaning solutions in distilled and artesian water. This value is below the permissible level for drinking water. When the concentration of phosphates increases to 100 and 1000 mg/dm3, their content in the permeate increases sharply to the values significantly higher than the permissible level in both drinking and wastewater. When sodium orthophosphate was added to artesian water, the effectiveness of its purification on this membrane with respect to chlorides, sulfates, hardness ions, and hydrocarbons was high. This indicates that the cartridges with these membranes can be used both in industrial installations and in households for further purification of artesian and tap water to drinking water quality.
EN
The processes of water purification with increasing selection of permeate were studied, considering selectivity and productivity of membranes, dynamics of changes of contents of components in the concentrate. It is shown that when chlorides and sulfates are removed from water, the increase in their content in the concentrate does not differ practically from the measured and calculated values. At the same time, the nature of dependences on the change in hardness, concentration of calcium and magnesium ions, alkalinity obtained experimentally differ significantly from the dependences obtained by theoretical calculations at permeate selection levels of > 70%. А significant difference in the determined and calculated concentrations of hardness ions in the concentrates was observed after hardness values greater than 30–40 mg-eq/dm3. This indicates the partial removal of hardness ions and carbonates from the concentrates, which may be the reason for the formation of deposits on the membrane. Permissible values of the degree of permeate selection were determined, at which there is no intense deposition of carbonates and hydroxides of hardness ions on the membrane. With the initial water hardness > 8 mg-eq/dm3, the degree of permeate selection could reach 60–70% without the risk of sedimentation on the membrane. Effectiveness of the low-pressure reverse osmosis membrane in the purification of mine water with an increased level of mineralization and hardness was determined. A significant difference between the determined and calculated hardness in concentration was observed already at the degree of permeate selection of 22–33%.
EN
Development of new and modification of existing chemicals, which act not only as binders, but also provide increased retention of fiber and other pulp components on the paper machine grid, accelerate pulp dehydration, and provide special properties (moisture resistance, heat resistance, improvement of other technical characteristics of paper and cardboard) of paper and cardboard, is an important and urgent task of chemical technology and ecology. This paper presents results of the corn starch modification with epoxypropyltriethanolammonium chloride, hexamethylolmelamine and hexamethylenetetramine. Modified starches provide the necessary strength indicators of cardboard from waste paper and low turbidity of wastewater. The obtained starches can be used in mills that use low-quality waste paper for the production of cardboard and paper products with the aim of saving fiber, reducing wastewater pollution and as a result reducing the negative impact on the environment.
EN
The process of extracting nitrates from water by the methods of reverse osmosis and ion exchange was investigated in the paper. In the formation of reverse osmosis, low-pressure membranes were used, and in ion-exchange processes, highly alkaline anionite AB–17–8 was applied in salt form. The dynamics of changes in the concentration of nitrates in the permeate and the concentration with an increase in the degree of permeate selection from 9 to 90% at initial nitrate concentrations of 18, 50 and 100 mg/dm3 were determined. The indicators of selectivity and productivity of membranes were calculated depending on the degree of permeate selection. It was shown that the low-pressure reverse osmosis membrane is characterized by low selectivity values at high productivity values in the selected part of the nitrate concentration. It was established that the ion exchange method is significantly more effective than reverse osmosis in removing nitrates from water. It ensures the reduction of nitrate content in purified water to a value of less than 1 mg/dm3 when the degree of their extraction is reached at the level of 99%. As the ionite is saturated with nitrates, the efficiency of their extraction decreases. Anionite sorbs nitrates effectively enough, being both in the chloride mixture and in the sulfate form. Nitrates are effectively desorbed by 2H solutions of sodium chloride and sodium or ammonium sulfate.
EN
The analysis of water conditioning methods for closed water supply systems was carried out in the work. The expediency of using redoxites based on ion exchange materials to combat the corrosion processes in water recirculation systems by preliminary deoxidation of water was shown. Modified KU-2–8, Dowex Mac-3, AB-17–8, Dowex Marathon WBA, AMBERLITE IRA 96 ion exchange resins were used as deoxidizing materials.
EN
The processes of manganese (II) ions removal from water using sorbent catalysts and ion exchange materials modified with iron oxides were studied. It was shown that manganese ions oxidize very slowly in artesian water, even when the pH is adjusted to 9.0. Intensive aeration of solutions due to stirring also does not promote the oxidation of manganese (II) ions. The degree of manganese extraction due to oxidation is reduced from 20–30% for solutions with a concentration of manganese ions of 1 and 5 mg/dm3 to 11–15% for solutions with a concentration of 15 and 30 mg/dm3. A significant increase in the oxidation efficiency of manganese ions was achieved by using magnetite as a sorbent catalyst. The efficiency of water demanganization increases along with the intensity of water aeration when mixing solutions. It was established that strongly acid cation exchangers provide efficient extraction of manganese ions from water. At the same time, a high exchange capacity of strong acid cation exchange resin KU-2–8 in acid and salt form was noted. It was shown that the capacity of manganese ions of this cation exchange resin in the Ca2+-form is slightly lower. When using the KU-2–8 in Ca2+-form of cation exchange resin to remove manganese ions from the solution already in the first samples, the leakage of manganese ions at the level of 10 mg/dm3 and above was observed. This indicates that this form of ion exchanger is not suitable for deep purification of water from manganese (II) ions. In order to increase the efficiency of manganese ion extraction from water, increase the duration of the filter cycle, magnetite and magnetite-modified KU-2–8 cation exchange resin were used as a sorbent-catalyst. It was shown that the cation exchange resin modified with magnetite provides the removal of a significant part of manganese ions due to catalytic oxidation on magnetite. The conditions of effective manganese extraction under static and dynamic conditions are determined.
EN
In this work, the process of water deironing by using magnetite as a catalyst to accelerate the oxidation of iron ions in an aqueous medium was investigated. It was shown that the efficiency of iron ion extraction depends on the solution concentration, sorbent dose and contact time. In all cases, the use of magnetite accelerated the process of extraction of iron by more than an order of magnitude in comparison with similar experiments on the oxidation of iron without the addition of a catalyst. At the pH values greater than 6, the use of magnetite as a catalyst contributes to the deep purification of water from iron ions.
EN
On a production scale, it is advisable to use mathematical models for predicting the treatment of effluents from heavy metal ions, which will increase the efficiency of enterprises. The sorption processes of copper, zinc, nickel and cadmium ions on the KU-2-8 cation exchange resin in the acid form at different concentrations were studied in this scientific work. At the same time, the sorption curves calculated were constructed using the Thomas model. The study results showed that this model very clearly describes the sorption processes of metals on the resin. Thus, it can be used to predict the processes of wastewater treatment in production.
EN
The main direction of the industrial development of Ukraine is the solving of the environmental pollution problems under the conditions of preservation of natural resources through complex use of raw materials with involvement of industrial wastes. The developed technology is intended for galvanic, accumulator, machine-building, mine and other enterprises, the wastewater from which contains ions of heavy metals. Heavy metal ions are extremely dangerous toxic substances because of a cumulative effect on aquatic organisms. In order to remove copper ions from aqueous solutions, the chemical precipitation with lime is used. The choice of reagent is associated with its cheapness. The most effective reagent precipitation of copper ions in the form of hydroxide occurs when the pH is raised to 10. In this work, the influence of sludge, which is formed as a result of water purification from copper ions, on the properties of cement was investigated. The effect was evaluated on the following properties: normal density of cement, hardening time, compressive strength at the age of 2 and 28 days and water separation coefficient. This allowed us to develop effective ways to their disposal. The developed method provides: a high degree of metal removal (up to 98-99%); simplicity of technological process; small capital and operating costs; complex technology of wastewater treatment process. Thus, the results of the study will contribute to the creation of low-waste and non-waste technologies for waste processing and disposal.
EN
In this work, the processes of electrochemical processing of sodium chloride solutions with the production of iron (III) chloride and alkali in a three-chamber electrolyzer with MA-41 anion-exchange membrane and MK-40 cation-exchange membrane were investigated. The conditions for the removal of sodium chloride from water in a three-chamber electrolyzer using an iron anode were determined depending on the anode current density and the reaction of the medium in the anode region. The parameters of the process of concentrating iron chloride in the anode region were established at relatively low concentrations of sodium chloride solution. It was shown that during the electrolysis of a sodium chloride solution with a concentration of 370 mg-eq/dm3 at a current of 0.2 A in a three-chamber electrolyzer with an iron anode, an iron chloride solution is formed in the anolyte at pH < 4.9. The rate of concentration of NaOH to catholyte and FeCl3 to anolyte increased along with the current density. It was found that in order to increase the concentration of iron (III) chloride in the anolyte at relatively low concentrations of sodium chloride solution, it is advisable to gradually renew the demineralized solutions in the working chamber.
EN
The problem of utilizing plant wastes of the agro-industrial complex is equally important and urgent. In this regard, it is advisable to develop a complex technology of plant waste application to solve the ecological problems of environmental pollution with heavy metals. Modification of walnuts shells with orthophosphoric acid has proven to be a promising process for obtaining the biosorbents with the efficient sorption properties. It was found out that the increase in the concentration of inorganic acid in modification time promotes the improvement in sorption capacity. Such biosorbents can be used in low-waste water demineralization systems. The utilization of waste biosorbents through the use in the composition of building materials is effective from an economic point of view. It was shown that the biosorbent acts as a fine additive; the increase in normal density and acceleration in hardening time takes place. At the same time, the compressive strength of the cement with the application of biosorbents decreases slightly. The results show that the modified walnuts shells have a slightly adverse effect on the hardening time of cement.
EN
The main aim of the scientific research was to study the ion-exchange processes in the treatment of industrial wastewaters containing a high concentration of heavy metal ions (Cu2+, Zn2+, Ni2+). The sorption results of heavy metal mixtures (Cu-Zn, Cu-Ni) from model solutions of sulfate salts on a strong-acid KU-2–8 cation exchanger in the H+-form were presented. The metals concentration was 10–50 meq/dm3. The efficiency conditions of cation regeneration in Cu2+-Zn2+, Cu2+-Ni2+-forms by 5, 8 and 10 % sulfuric acid solutions were studied. It was shown that the heavy metals from aqueous media can be removed not only from ion exchangers, but can also be restored from regenerative solutions by electrolysis to obtain metals in pure form. In general, the research results showed that the use of ion exchange is very effective in removing the heavy metal ions. The sorption efficiency and regeneration efficiency was about 100%.
EN
In this study, the processes of electrochemical oxidation of ammonia in a two-chamber electrolyzer with anion exchange membrane MA-41 were investigated. An estimation of the efficiency of the process of oxidation of ammonia, depending on the chemical composition of the initial solution of anolyte and catholyte, current density and time of electrolysis was carried out. It was shown that the oxidation of ammonia in the anode chamber passes quickly and is accompanied by a significant decrease in pH due to the formation of nitrogen dioxide and nitrates. At the same time, the current output and the electrical conductivity of the dilute solutions was rather low. The effect of chlorides on the process of electrolysis was investigated. It was shown that the presence of chlorides in the anolyte catalyzes the processes of oxidation of ammonia. An increase in the concentration of chlorides in the anolyte increases output and reduces electricity consumption. The presence of chlorides in the catholyte does not accelerate oxidation. The presence of sulfates, both in the anolyte and in the catholyte, slows down the process of oxidation of ammonia as a result of the oxidation of sulfates to persulfates, which are quite passive to ammonium ions. At the same time, electricity consumption increases.
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