Nurzat ŞAYKİYEVA | Mustafa DOLAZ | Zarlık MAYMEKOV | Mehmet KOBYA

Article | 2023 | Theoretical Foundations of Chemical Engineering57 ( 6 )

In this study, sulfide removal was carried out in the Electrocoagulation process under controlled and uncontrolled pH conditions. Under optimum conditions, electrocoagulation took place in less than 40 minutes at uncontrolled pH and less than 30 minutes at controlled pH to reduce the sulfite concentration of the effluent below 0.5 mg/L. The reaction rate constant and iron-sulfide molar ratio for sulfide removal were 14.09 x 10(-2) min(-1) and 0.97 mol/mol, respectively; under uncontrolled pH conditions, they were 22.88 x 10(-2) and 0.97 mol/mol at controlled pH. The mg sulfide removed per g Fe was calculated as 654.0 mg S2-/g Fe at . . .uncontrolled pH and 508.46 mg S2-/g Fe at controlled pH. The operating costs for uncontrolled and controlled pH conditions were also calculated as 2.063 /m(3) (0.747 /kg S) and 0.842 /m(3) (0.628 /kg S), respectively. Controlled pH conditions were important in sulfide removal by the Electrocoagulation process. Keyword: electrocoagulation; iron electrode; pH control; sulfide remova More less

Zarlık MAYMEKOV | Canarbek İZAKOV | Nurzat ŞAYKİYEVA | Mustafa DOLAZ | Mehmet KOBYA

Article | 2023 | Theoretical Foundations of Chemical Engineering57 ( 2 )

Under practical conditions, one of the possible solutions to the problem of treatment of hydrogen-sulfide-containing industrial wastewater is the electrochemical oxidation of sulfides. In this work, the model system Fe-NaCl-Na2S-H2SO4-H2O is considered, an experimental setup is constructed, and the electrocoagulation process is studied in a wide (288-308 K) range of temperatures of an aqueous solution of hydrogen sulfide. The optimal ratios between the initial components in the system are determined. The experimental and calculated pH of the solution are found. The system is thermodynamically modeled by minimizing the Gibbs energy, . . .and the concentration distribution of individual molecules and other species (cations, anions) in the solution is characterized. Possible chemical reactions in the system Fe-NaCl-Na2S-H2SO4-H2O during the electrocoagulation of hydrogen-sulfide-containing wastewater are identified. Eh-pH diagrams are constructed to compare the redox potentials of the systems Fe-H2O, Fe-H2O-S, and Fe-NaCl-Na2S-H2SO4-H2O based on the determined concentrations of iron- and sulfur-containing particles in the solution. A calculation formula for the redox potential Eh of the system is obtained. Keyword: distribution; electrocoagulation; hydrogen sulfide; iron; particle; sodium chloride; sodium sulfide; wate More less

Mirlan MOLDOBAYEV | Zarlık MAYMEKOV

Article | 2023 | Theoretical Foundations of Chemical Engineering57 ( 5 )

To predict and evaluate the carbon footprint in the gas phase, furnace fuel oil oxidation in excess air (alpha factor 1.3) was studied over a wide temperature (T 298–3000 K, P 0.1 MPa). Equilibrium thermodynamic parameters (entropy, enthalpy, and internal energy) and the concentration distributions of C-, S-, N-, O-, and H-containing components and active particles in the gas phase were determined. Based on the total concentration distribution of C-, S-, N-, O-, and H-containing components and active particles in the gas phase, the weight content of carbon was calculated. Taking into account the chemical matrix of the furnace fuel o . . .il–air system and the weight content of carbon, the man-made load of carbon in the gas phase was found. The results of the work made it possible to evaluate the carbon footprint in the gas phase because of the combustion of fuel, in particular, furnace fuel oil in air. Reduction of the man-made load of carbon oxides (CO, CO2) in the gas phase was achieved by modifying and burning furnace fuel oil in the form of oil-in-water (reverse) emulsions in E-1/9M industrial boilers. Keyword: carbon footprint; concentration distribution; furnace fuel oil–air; gas phase; man-made loa More less