Oxygen transfer capacity of the copper component introduced into the defected-MgMnAlO4 spinel structure in CH4-CO2/air redox cycles

2019 ◽  
Vol 36 (12) ◽  
pp. 1971-1982
Author(s):  
Namgyu Son ◽  
Jeong Yeon Do ◽  
No-Kuk Park ◽  
Ui Sik Kim ◽  
Jeom-In Baek ◽  
...  
Keyword(s):  
Oxygen Transfer ◽  
Spinel Structure ◽  
Redox Cycles ◽  
Copper Component ◽  
Oxygen Transfer Capacity

Study of a Non-Conventional Aeration System

1987 ◽  
Vol 19 (5-6) ◽  
pp. 869-876
Author(s):  
L. Raschid-Sally ◽  
M. Roustan ◽  
H. Roques ◽  
G. M. Faup
Keyword(s):  
Oxygen Transfer ◽  
Peclet Number ◽  
Péclet Number ◽  
Theoretical Approaches ◽  
Aeration System ◽  
Circulation Velocity ◽  
The Mean ◽  
Oxygen Transfer Capacity ◽  
Mean Circulation ◽  
Conventional Systems

A non-conventional aeration system for oxidation ditches using jets has been developed. The principle of this system is based on the separation of the 2 actions: aeration and circulation. It was concluded that the flow of the liquid in the channel can be successfully modelled using various theoretical approaches. The mean circulation velocity VC, the power dissipated P, and the Peclet number Pe are the 3 important parameters governing the circulation. The oxygen transfer capacity of the system has been studied and compares favourably with that of conventional systems. The advantage of such systems over conventional ones has been discussed.

scholarly journals Oxygen Transfer Capacity as a Measure of Water Aeration by Floating Reed Plants: Initial Laboratory Studies

Processes ◽  
2020 ◽  
Vol 8 (10) ◽  
pp. 1270
Author(s):  
Antonio Albuquerque ◽  
Peter Randerson ◽  
Andrzej Białowiec
Keyword(s):  
Oxygen Transfer ◽  
Laboratory Experiments ◽  
Aquatic Plant ◽  
Dry Mass ◽  
Ammonia Nitrogen ◽  
Subsurface Environment ◽  
Floating Vegetation ◽  
Reed Plants ◽  
The Individual ◽  
Oxygen Transfer Capacity

Reed-Phragmites australis (Cav.) Trin. ex Steud, an aquatic plant, commonly used in constructed wetlands for wastewater treatment, supplies oxygen into the subsurface environment. Reed may be used as a ‘green machine’ in the form of a floating vegetation cover with many applications: wastewater lagoons, manure lagoons or sewage sludge lagoons. An important measure of the performance of the plant system is the oxygen transfer capacity (OTC). Accurate prediction of the OTC in relation to reed biomass would be crucial in modelling its influence on organic matter degradation and ammonia–nitrogen oxygenation in such lagoons. Laboratory experiments aiming to determine OTC and its dependence on reed biomass were carried out. Eight plants with a total dry mass ranging from approximately 3 to 7 g were tested. Mean OTC was determined per plant: 0.18 ± 0.21 (g O2·m−3·h−1·plant−1), with respect to leaves-and-stem dry mass (dlsm): 44.91 ± 35.21 (g O2·m−3·h−1·g dlsm−1), and to total dry mass (dtm): 33.25 ± 27.97 (g O2·m−3·h−1·g dtm−1). In relation to the relatively small root dry mass (drm), the OTC value was 136.02 ± 147.19 (g O2·m−3·h−1·g drm−1). Measured OTC values varied widely between the individual plants (variation coefficient 115%), in accordance with their differing size. Oxygenation performance was greatest in the reed plants with larger above ground dry mass (>4 g dlsm), but no influence of the root dry mass on the OTC rate was found.

Analysis of Oxygen Transfer and Dissolved Oxygen Concentration Measurement Tests in a Wastewater Treatment Plant

2014 ◽  
Vol 656 ◽  
pp. 486-494
Author(s):  
Marius Daniel Roman ◽  
Raluca Andreea Felseghi
Keyword(s):  
Dissolved Oxygen ◽  
Oxygen Concentration ◽  
Oxygen Transfer ◽  
Treatment Plant ◽  
Dissolved Oxygen Concentration ◽  
Coverage Area ◽  
Type Size ◽  
Oxygen Efficiency ◽  
Oxygen Transfer Capacity ◽  
Tank Geometry

The efficiency of oxygen transfer depends on many factors including the type, size and shape of diffusers and the tank geometry. In this paper, the effect of the depth of water in the tank and the extension of coverage area of diffusers on each of oxygen transfer capacity, efficiency and dissolved oxygen concentration is tested. Experimental procedure is adopted to evaluate the effect of dissolved oxygen concentration. The results of the case study showed that, both the depth of water and the extent of coverage area of diffuser had a significant effect on the tested parameters. The values of oxygen transfer capacity was 76,7 kg O2/h and oxygen efficiency (without agitation): 5,3 kg O2/h, oxygen efficiency (with agitation): 4,2 kg O2/h.

scholarly journals Copper Aluminum Spinels Doped with Cerium as Catalysts for NO Removal

Catalysts ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1388
Author(s):  
Anna Białas ◽  
Kamil Rugała ◽  
Cezary Czosnek ◽  
Grzegorz Mordarski ◽  
Jacek Gurgul
Keyword(s):  
Spinel Structure ◽  
Catalyst Surface ◽  
Catalytic Reduction ◽  
Atomic Ratio ◽  
Trivalent Cation ◽  
Inverse Spinel ◽  
No Removal ◽  
Redox Cycles ◽  
Mesoporous Solids ◽  
Copper Aluminum

Cu-Ce(Mn)-Al oxide catalysts to NO removal in the broad temperature range were synthesized and tested. The precursor of copper aluminium spinel was obtained with the coprecipitation method. By this method, Cu–Al spinels with various amounts of manganese and cerium were synthesized as well. These oxides crystallized in the structure of inverse spinel; however, Ce doping caused the appearance of additional CeO2 phase as determined by XRD. The samples were mesoporous solids with moderate surface area and porosity measured by low temperature sorption of nitrogen. The addition of another metal to Cu–Al spinel caused an increase of activity in selective catalytic reduction of nitrogen oxide with ammonia. The presence of manganese caused the formation of a higher amount of N2O by-product. The catalytic activity increased with the cerium concentration. For the sample with the atomic ratio Ce0.15Cu0.18, ca. 90% of NO conversion was registered between 200 and 350 °C. As examined with XPS spectroscopy, such conversion was attained due to the good dispersion of copper on the catalyst surface. This copper was placed mainly in spinel octahedral positions which enable its easier reduction. The spinel structure causes the presence of cerium as the trivalent cation important in redox cycles with the participation of copper.

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