scholarly journals Mechanism of sorption-catalytic purification of water from manganese ions

Author(s):  
Микола Дмитрович Гомеля ◽  
Марія Миколаївна Твердохліб ◽  
Іванна Петрівна Возна
1892 ◽  
Vol 34 (861supp) ◽  
pp. 13759-13760
Author(s):  
Wm. P. Mason.

1891 ◽  
Vol 32 (834supp) ◽  
pp. 13327-13328
Author(s):  
Albert R. Leeds

Author(s):  
Veena Vijayan ◽  
Suguna Yesodharan ◽  
E. P. Yesodharan

Solar photocatalysis as a potential green technology for the removal of traces of the dye pollutant Indigo carmine (IC) from water is investigated using ZnO as the catalyst. Degradation/decolorization alone does not result in complete decontamination as seen from the significant Chemical Oxygen Demand (COD) of water even after the parent compound has disappeared completely. The degradation proceeds through many intermediates which also get mineralized eventually but slowly. Oxalic acid is identified as a stable slow mineralizing degradation product which itself is formed from other transient intermediates. Effect of various parameters such as catalyst dosage, concentration of the dye, pH, temperature, presence of contaminant salts etc. on the degradation is investigated and quantified. Oxidants such as S2O82- and H2O2 have only moderate influence on the degradation. The degradation follows variable kinetics depending on the concentration of the substrate. The reaction proceeds very slowly in the absence of O2 indicating the importance of reactive oxygen species and hydroxyl free radicals in photocatalysis. H2O2 formed insitu in the system undergoes concurrent decomposition resulting in stabilization in its concentration. The study demonstrates that solar photocatalysis can be used as a viable tool for the purification of water contaminated with traces of IC.


2020 ◽  
pp. 34-43
Author(s):  
N. R. Memetov ◽  
◽  
A. V. Gerasimova ◽  
A. E. Kucherova ◽  
◽  
...  

The paper evaluates the effectiveness of the use of graphene nanostructures in the purification of lead (II) ions to improve the ecological situation of water bodies. The mechanisms and characteristic parameters of the adsorption process were analyzed using empirical models of isotherms at temperatures of 298, 303, 313 and 323 K, which correspond to the following order (based on the correlation coefficient): Langmuir (0.99) > Temkin (0.97) > Dubinin – Radushkevich (0.90). The maximum adsorption capacity of the material corresponds to the range from 230 to 260 mg/g. We research the equilibrium at the level of thermodynamic parameter estimates, which indicates the spontaneity of the process, the endothermic nature and structure change of graphene modified with phenol-formaldehyde resin during the adsorption of lead (II) ions, leading to an increase in the disorder of the system.


2016 ◽  
Vol 55 (2) ◽  
pp. 027-032
Author(s):  
Yulia N. Shaplygina ◽  
◽  
Tatyana F. Kurochkina ◽  
Botagoz M. Nasibulina ◽  
◽  
...  

Photonics ◽  
2019 ◽  
Vol 6 (4) ◽  
pp. 107
Author(s):  
Yuriy G. Galyametdinov ◽  
Dmitriy O. Sagdeev ◽  
Andrey A. Sukhanov ◽  
Violeta K. Voronkova ◽  
Radik R. Shamilov

Synthesis of nanoparticles doped with various ions can significantly expand their functionality. The conditions of synthesis exert significant influence on the distribution nature of doped ions and therefore the physicochemical properties of nanoparticles. In this paper, a correlation between the conditions of synthesis of manganese-containing cadmium sulfide or zinc sulfide nanoparticles and their optical and magnetic properties is analyzed. Electron paramagnetic resonance was used to study the distribution of manganese ions in nanoparticles and the intensity of interaction between them depending on the conditions of synthesis of nanoparticles, the concentration of manganese, and the type of initial semiconductor. The increase of manganese concentration is shown to result in the formation of smaller CdS-based nanoparticles. Luminescent properties of nanoparticles were studied. The 580 nm peak, which is typical for manganese ions, becomes more distinguished with the increase of their concentration and the time of synthesis.


Coatings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 151
Author(s):  
Yuyang Liu ◽  
Chang-Hwan Choi

Sand, a cheap and naturally abundant particulate material, was modified with photocatalytic and hydrophobic coatings to reduce evaporation loss and facilitate the purification of water. The first-level photocatalytic coatings (TiO2 or ZnO nanocrystals) rendered nanoscale roughness on the surface of the sand. The additional second-level hydrophobic coating of a self-assembled monolayer of octyltrimethoxysilane (OTS) made the sand particles superhydrophobic because of the nanoscale roughness imposed by the nanocrystals. The superhydrophobic sand particles, floating on the free surface of water due to their superhydrophobicity, significantly reduced the evaporation loss of water by 60%–90% in comparison to an uncovered water surface. When the outer hydrophobic coatings are weathered or disengaged, the inner photocatalytic coatings become exposed to water. Then, the sand particles act as photocatalysts to degrade the contaminants in water under solar radiation.


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