Chemistry Journal of Moldova

DOI: http://dx.doi.org/10.19261/cjm.2021.792

 

Graphical Abstract: This study presents an investigation of the use of the natural mineral of Nakhchivan Autonomous Republic to produce analcime zeolite of potential practical importance. The influence of temperature and crystallization time, the concentration of alkaline solution and mineralizer on the process of synthesis of analcime has been evaluated. The optimal conditions established for the synthesis of pure analcime with a 100% degree of crystallinity are as follows: temperature of 180°C, alkaline and mineralizer solution of 10-15% KOH and 5-10% KCl and processing time of 50 hours. It has been shown that the presence of the KCl mineralizer promotes the production of pure analcime with a 100% crystallinity, and the natural mineral of Nakhchivan represents a good source for the synthesis process.


 

DOI: http://dx.doi.org/10.19261/cjm.2021.796

 

Graphical Abstract: The photochemical transformations of thioglycolic acid using model systems was studied by varying the irradiation sources and the kinetic parameters were determined. It was found that thioglycolic acid undergoes destruction on induced photolysis in the presence of humic substances, and its half-life can be estimated as 10-14 days, depending on weather conditions (cloudiness, time of day, season etc.). Results obtained in the course of this study on model systems were transferred to natural waters, and it was concluded that thioglycolic acid has a positive influence on the chemical self-purification processes of water, in the natural aquatic environment. This is manifested by increasing the self-purification capacity of water, due to the generation of active oxygen species, which lead to the degradation not only of this thiol, but of other pollutants present in aquatic environment, as well. At the same time, the products of the transformations are harmless to the aquatic environment and hydrobionts.


 

DOI: http://dx.doi.org/10.19261/cjm.2021.779

 

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.