Chemistry Journal of Moldova

Industrial chemistry

EVALUATING THE METHODS USED FOR THE REGENERATION PROCESS OF COPPER-ZINC SOLUTIONS

Author(s):

Vita Datsenko and Vasyl Larin


Field: Industrial chemistry
Type: Research paper
Issue: 2021 Volume 16, no.1
Pages: 88-98
Keywords: waste, heavy metal, regeneration, reagent method, treatment efficiency.
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DOI: http://dx.doi.org/10.19261/cjm.2021.793

Abstract (PDF) 
Graphical Abstract: The purpose of this study was to investigate the physicochemical particularities of the regeneration processes that occur in spent sulphate copper-zinc solutions using the reagent methods of crystallization, cementation, and sedimentation. A comparative analysis of the results of the studies of regeneration processes has shown that the content of the extraction of Cu2+ and Zn2+ ions by the crystallization method makes up to 97.2% and 49.7%, respectively; by the contact displacement method to 99.9% and 95.4%, respectively; and by the deposition method it makes up to 99.9% and 99.9%, respectively. The presented study can be used for improvements in the electroplating productivity.


 

Downloads: 57

A MODIFIED SCHEFFE'S SIMPLEX LATTICE DESIGN METHOD IN DEVELOPMENT OF CERAMIC CARRIERS FOR CATALYTIC NEUTRALIZERS OF GAS EMISSIONS

Author(s):

Valery Ved, Hanna Ponomarenko, Yevhenia Ponomarenko, Konstantin Gorbunov


Field: Industrial chemistry
Type: Research paper
Issue: 2021 Volume 16, no.1
Pages: 79-87
Keywords: Scheffe's simplex lattice design method, ceramic carrier, catalytic converter, gas emission.
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DOI: http://dx.doi.org/10.19261/cjm.2021.779

Abstract (PDF) 
Supplementary Material (PDF)
Graphical Abstract:
A modified Scheffe's simplex lattice design method is proposed to study the properties of multicomponent materials. This modified Scheffe's method allowed determining the optimal compositions of cordierite and corundum based ceramic materials that are used as catalyst carrier for gas purification equipment. The obtained material (0.63-1.25 mm weight fraction of cordierite of 0.35 mass% fraction; <0.63 mm weight fraction of cordierite of 0.35 mass% fraction; <0.06 mm weight fraction of corundum of 0.2 mass% fraction; 1.25-2.5 mm weight fraction of cordierite of 0.2 mass% fraction) was used successfully for the manufacturing of catalytic neutralizers of gas emissions. 








Downloads: 37

DECOLOURISATION OF BEET SUGAR SYRUP USING ACTIVATED CARBON AND GLUCOSE OXIDASE ENZYME

Author(s):

Pezhman Zolfaghari, Neda Imani Payandeh, Mortaza Golizadeh, Afzal Karimi, Amirali Ebadi Fard Azar


Field: Industrial chemistry
Type: Research paper
Issue: 2020 Volume 15, no.2
Pages: 54-61
Keywords: beet sugar syrup, decolourisation, activated carbon, hydrogen peroxide, glucose oxidase.
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DOI: http://dx.doi.org/10.19261/cjm.2020.775

Abstract (PDF)
Graphical Abstract: This paper presents the development and optimization of a new approach which combines the utilization of activated carbon and glucose oxidase enzyme for decolourisation of beet sugar syrup. The combining of the physical adsorption with the enzymatic reaction was managed to improve the decolourisation of beet sugar syrup from 35.29 to 83.68% compared to the basic adsorption by activated carbon after 120 min of operation under the optimum conditions. The maximum decolourisation efficiency by the coupled process was achieved at glucose oxidase dosage of 0.07 g, glucose concentration of 20 mM, and solution pH 7 at the temperature of 30ºC using 0.01 g of activated carbon particles. Given the high effectiveness, reusability, and the eco-friendly nature of the process, the proposed method can serve as an alternative to ordinary decoloursation techniques.



 

Downloads: 68

EVALUATION OF THE THERMAL BEHAVIOUR OF AGRICULTURAL WASTES FOR POSSIBLE USE IN THE BIOMASS PELLETS INDUSTRY

Author(s):

Alexandra Marcu, Gabriela Lisa, Ioana-Emilia Sofran, Ion Anghel, Manuel Serban


Field: Industrial chemistry
Type: Research paper
Issue: 2020 Volume 15, no.1
Pages: 58-66
Keywords: waste, biomass pellet, combustion heat, thermogravimetric analysis, microscale combustion calorimetry.
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DOI: http://dx.doi.org/10.19261/cjm.2020.717   
 
Abstract (PDF)
Supplementary Material (PDF)
Graphical Abstract: This paper tackles the potential uses of agricultural wastes (sawdust, sunflower seed shells, pumpkin seed shells, cherry pits, walnut shells, and green walnut shells) for the production of pellets. Combustion heat was determined for these wastes and their thermal decomposition in an air atmosphere was analysed. Five types of mini-pellets were made from different combinations of available wastes and their thermal behaviour was analysed by the microscale combustion calorimetry method.
 

 

Downloads: 229

TREATMENT OF SECONDARY RAW MATERIALS BY INNOVATIVE PROCESSES

Author(s):

Stefano Ubaldini, Daniela Guglietta, Francesca Trapasso, Serena Carloni, Daniele Passeri, Adalgisa Scotti


Field: Industrial chemistry
Type: Invited paper
Issue: 2019 Volume 14, no.1
Pages: 32-46
Keywords: critical raw material, precious metal, circular economy, bio-hydrometallurgy, electrowinning.
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DOI: http://dx.doi.org/10.19261/cjm.2019.585 

Abstract (PDF)
Graphical Abstract: This paper presents an overview of the various innovative methodologies used in the recovery of valuable metals and critical raw materials from secondary sources. The review also highlights the used varieties of application on large scale in real situations and hopes to provide insights into valorization of spent sources.




Downloads: 124

METALLURGICAL COKEMAKING WITH THE IMPROVED PHYSICOCHEMICAL PARAMETERS AT AVDEEVKA COKE PLANT

Author(s):

Oleg Zelenskii, Yuriy Vasil’ev, Alexey Sytnik, Natalia Desna, Elena Spirina, Andrey Grigorov


Field: Industrial chemistry
Type: Research paper
Issue: 2018 Volume 13, no.2
Pages: 32-37
Keywords: coal, electrocorundum, carborundum, blend, coke.
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DOI: http://dx.doi.org/10.19261/cjm.2018.516   

Abstract (PDF) 
Graphical Abstract: The article presents the results of studies regarding the improvement of the qualitative characteristics of blast furnace coke obtained from modified coal blend in industrial conditions of Avdeevka Coke Plant. Inorganic corundum powders are applied to modify the coal blend, namely electrocorundum (α-Al2O3) and carborundum (α-SiC). The introduction of a specific quantity (0.25 wt %) of non-clinkering additives allows the modification of the processes that occur when the coal blend is plastic, with consequent improvement in coke strength.


 

Downloads: 76

THE EFFECT OF RICE HUSK ON THE PHASE FORMATION AND CEMENT CLINKER PROPERTIES

Author(s):

Lev Chernyak, Liubov Melnyk, Natalia Dorogan


Field: Industrial chemistry
Type: Research paper
Issue: 2018 Volume 13, no.2
Pages: 24-31
Keywords: cement, clinker, rice husk, crystalline phase, property.
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DOI: http://dx.doi.org/10.19261/cjm.2018.502   

Abstract (PDF) 
Graphical Abstract: The features of the cement clinker when rice husk is used are investigated. The dependence of the raw mixture composition on the set product burning characteristics has been analysed using the software “CLINKER”. The mixture compositions have been identified on the basis of the chalk–clay–rice husk system, with the introduction of man-made stock of 6.0–18.0 mass %. The features of the phase composition and the binder properties, by varying the rice husk content, mixture ratio and burning temperature are shown.


 

Downloads: 51

PREPARATION AND CHARACTERIZATION OF MICROFILTRATION CERAMIC MEMBRANES BASED ON NATURAL QUARTZ SAND

Author(s):

Andrei Ivanets, Vladimir Agabekov


Field: Industrial chemistry
Type: Research paper
Issue: 2017 Volume 12, no.1
Pages: 67-73
Keywords: ceramic, membrane, microfiltration, quartz sand.
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DOI: dx.doi.org/10.19261/cjm.2017.407 
 
Abstract (PDF)
Graphical Abstract:
 The effect of phase and chemical composition of natural quartz sand, binder and burnable additives was studied. The conditions of application of the membrane and biocide layers on the formation of porous ceramic and microfiltration membranes were investigated. It is shown that a crystalline oxide of Si(IV) is determinant for obtaining the ceramic materials. The presence of carbonates (calcite, dolomite, aragonite, etc.) and crystalline aluminosilicates (microcline, albite, phlogopit, etc.) leads to a decrease in mechanical strength of ceramics. The biocide coating designed to protect the ceramic membrane surfaces from biofouling was applied and its anti-bacterial activity was shown.


Downloads: 82

A PERSPECTIVE FOR POOR WASTEWATER INFRASTRUCTURE REGIONS: A SMALL-SCALE SEQUENCING BATCH REACTOR TREATMENT SYSTEM

Author(s):

Narcis Barsan, Valentin Nedeff, Antonina Temea, Emilian Mosnegutu, Alexandra Dana Chitimus, Claudia Tomozei


Field: Industrial chemistry
Type: Research paper
Issue: 2017 Volume 12, no.1
Pages: 61-66
Keywords: municipal wastewater, Sequencing Batch Reactor (SBR), legislative regulations.
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DOI:
dx.doi.org/10.19261/cjm.2017.387

Abstract (PDF)
Graphical Abstract:
 Comparing the problems in Romania and Senegal, regarding wastewater treatment, the present paper aims to identify the best methods and techniques to treat the municipal wastewater in small treatment plants with sequential operation. This paper examines the possibility of using Sequencing Batch Reactor (SBR) process to treat the municipal wastewater characterized by low flow. This paper also presents a comparative analysis of the degree of purification achieved in a SBR wastewater treatment plant, as well as legislative regulations in Romania and Senegal. Finally, the paper identifies the possible uses of the treated wastewater in different household activities.


 

Downloads: 55

NEURAL MODELING AND OPTIMIZATION OF A MECHANICAL-CHEMICAL TREATMENT APPLIED FOR SOME INDUSTRIAL EFFLUENTS. A ROUMANIAN CASE STUDY

Author(s):

Rodica Mariana Diaconescu, Carmen Zaharia


Field: Industrial chemistry
Type: Research paper
Issue: 2017 Volume 12, no.2
Pages: 19-27
Keywords: artificial neural network (ANN), industrial wastewater treatment, multilayers perceptron model (MLP).
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DOI:
dx.doi.org/10.19261/cjm.2017.394   
 
Abstract (PDF)
Graphical Abstract:  The paper proposes an artificial neural network model of multilayers perceptron type (MLP3:10:1) adapted for mechanical-chemical treatment system of an industrial effluent (i.e. coagulation-flocculation - sedimentation applied for an industrial effluent produced in a manufacturing plant of bricks and other ceramics) which is further optimized and tested for its validation.

Downloads: 45