scholarly journals Influence of alkalinization over MIL-100(Fe) for enhanced VOCs adsorbents

2021 ◽  
Author(s):  
Xinyu Xie ◽  
Joy Thomas ◽  
Chang-Tang Chang ◽  
Hong Tao
Keyword(s):  
Research Work ◽  
Rate Limiting Step ◽  
Acetone Adsorption ◽  
Gas Phase Adsorption ◽  
Layer Adsorption ◽  
Volatile Organic ◽  
Metal Organic ◽  
To Come ◽  
Pressure Swing ◽  
Rate Limiting

Abstract Substantial attempts have been undertaken for the improvement of the air quality over decades; and Volatile Organic Compounds (VOCs) from the chemical and textile industries are truly listed as severe issue to be controlled. To come up with modus operandi for this issue, a novel composite of metal organic frameworks (MOFs) MIL-100(Fe) with salient tuned features of natrite was designed by a green and facile method. Mineralized composite MIL-100(Fe) exhibited enhanced crystallinity than pure MIL-100(Fe) as well showcased a higher surface area of 1300 m2g− 1. Through dynamic acetone pressure swing adsorption setup, MIL-0.05Na revealed an enhanced acetone adsorption of 210 mg g− 1 at room temperature. Gas phase adsorption isotherms confirmed the mono layer adsorption behavior. The kinetics models evaluated that the external mass transfer was the rate limiting step for surface adsorption. The thermodynamic study manifested that the adsorption reaction was spontaneous and exothermic. The proposed mechanism of adsorption was the act of physisorption which enriched the adsorbents reusability. This research work provides a futuristic vista to design mineralized Fe-MOFs composites for an energy saving adsorbents for VOCs removal.

Influence of Alkalinization Over Metal Organic Frameworks MIL-100(Fe) for Enhanced Volatile Organic Compounds (VOCs) Adsorbents

2021 ◽  
Vol 21 (11) ◽  
pp. 5510-5521
Author(s):  
Xinyu Xie ◽  
Joy Thomas ◽  
Chang-Tang Chang ◽  
Hong Tao
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Metal Organic Frameworks ◽  
Research Work ◽  
Rate Limiting Step ◽  
Gas Phase Adsorption ◽  
Volatile Organic ◽  
Metal Organic ◽  
To Come ◽  
Pressure Swing

Substantial attempts have been undertaken for the improvement of the air quality over decades; and Volatile Organic Compounds (VOCs) from the chemical and textile industries are truly listed as severe issue to be controlled. To come up with modus operandi for this issue, a novel composite of metal organic frameworks (MOFs) MIL-100(Fe) with salient tuned features of natrite was designed by a green and facile method. Mineralized composite MOFs exhibited enhanced crystallinity than pure MIL-100(Fe) as well showcased a higher surface area of 1300 m2 g−1. Through dynamic acetone pressure swing adsorption setup, MIL-0.05Na (MIL-100(Fe) synthesized with 0.05 mM Na2CO3 solution) revealed an enhanced acetone adsorption of 210 mg g 1 at room temperature. Gas phase adsorption isotherms confirmed the mono layer adsorption behavior. The kinetics models evaluated that the external mass transfer was the rate limiting step for surface adsorption. The thermodynamic study manifested that the adsorption reaction was spontaneous and exothermic. The proposed mechanism of adsorption was the act of physisorption which enriched the adsorbents reusability. This research work provides a futuristic vista to design mineralized Fe-MOFs composites for an energy saving adsorbents for VOCs removal.

Biochars prepared from rabbit manure for the adsorption of rhodamine B and Congo red: characterisation, kinetics, isotherms and thermodynamic studies

2020 ◽  
Vol 81 (3) ◽  
pp. 436-444
Author(s):  
Wen Huang ◽  
Min Zhang ◽  
Yinhai Wang ◽  
Jiao Chen ◽  
Jianqiang Zhang
Keyword(s):  
Rhodamine B ◽  
Congo Red ◽  
Molecular Layer ◽  
Suitable Model ◽  
Related Factors ◽  
Adsorption Sites ◽  
Rate Limiting Step ◽  
Layer Adsorption ◽  
Pseudo Second Order ◽  
Rate Limiting

Abstract Biochar was prepared from rabbit faeces (RFB550) at 550 °C through pyrolysis and was characterised using elemental analysis, scanning electron microscopy, Brunauer–Emmett–Teller analysis and Fourier transform infrared spectroscopy (FTIR). The related factors, kinetics, isothermal curves and thermodynamics of the adsorption behaviours were investigated by conducting batch experiments. The results revealed the adsorption equilibrium of rhodamine B (RhB) and Congo red (CR) onto RFB550 with initial concentrations of 30 mg · L−1 at 25 °C and 210 min, and the best adsorption was observed when the pH of the RhB and CR solutions was 3 and 5, respectively. Pseudo-second-order kinetics was the most suitable model for describing the adsorption of RhB and CR onto RFB550, indicating that the rate-limiting step was mainly chemical adsorption. The isotherm data were best described by the Freundlich model, and the adsorption process was multi-molecular layer adsorption. Thermodynamic parameters revealed the spontaneous adsorption of RhB and CR onto RFB550. According to the results of the FTIR analysis, the oxygen-containing functional groups and aromatic structures on the surface of RFB550 provided abundant adsorption sites for RhB and CR, and the adsorption mechanism was potentially related to the hydrogen bonds and π–π bonds.

A modified capillary suction time apparatus for measuring the filterability of super-flocculated sludges

2000 ◽  
Vol 42 (9) ◽  
pp. 135-139 ◽  
Author(s):  
P. A. Vesilind ◽  
B. Örmeci
Keyword(s):  
Filter Paper ◽  
Free Water ◽  
Quantitative Measure ◽  
Water Release ◽  
Capillary Suction ◽  
Freeze Thaw ◽  
Rate Limiting Step ◽  
Limiting Step ◽  
To Come ◽  
Rate Limiting

The capillary suction time (CST) test provides a quantitative measure of the rate of water release from a sludge and has the advantage of being simple to run. The test consists of allowing sludge water to filter into and penetrate a filter paper by capillary force. Although the CST works well for the majority of sludges, it is not a useful test for measuring the filterability of highly flocculated sludges or sludges conditioned by other methods such as freeze-thaw. The escape of water from the sludge in such cases is too fast and the rate-limiting step becomes the movement of water through the filter paper instead of the release of water from the sludge. There is a need to improve the CST apparatus so it can be used to measure the degree of filterability for super flocculated sludges as well. Such a device is described in this paper. It consists of first draining the free water from the well-flocculated sludge and only then allowing the flocculated sludge to come in contact with the filter paper.The results of our study show that the filterability of super-flocculated sludges can be measured with acceptable precision using the modified CST apparatus.

Ornithine Decarboxylase Activity in Cultured Endothelial Cells Stimulated by Serum, Thrombin and Serotonin

1978 ◽  
Vol 39 (02) ◽  
pp. 496-503 ◽  
Author(s):  
P A D’Amore ◽  
H B Hechtman ◽  
D Shepro
Keyword(s):  
Endothelial Cells ◽  
Ornithine Decarboxylase ◽  
Decarboxylase Activity ◽  
Aortic Endothelial Cells ◽  
Ornithine Decarboxylase Activity ◽  
Rate Limiting Step ◽  
Bovine Aortic Endothelial Cells ◽  
Limiting Step ◽  
Rate Limiting ◽  
Serum Serotonin

SummaryOrnithine decarboxylase (ODC) activity, the rate-limiting step in the synthesis of polyamines, can be demonstrated in cultured, bovine, aortic endothelial cells (EC). Serum, serotonin and thrombin produce a rise in ODC activity. The serotonin-induced ODC activity is significantly blocked by imipramine (10-5 M) or Lilly 11 0140 (10-6M). Preincubation of EC with these blockers together almost completely depresses the 5-HT-stimulated ODC activity. These observations suggest a manner by which platelets may maintain EC structural and metabolic soundness.

Dynamics of hepatic and peripheral insulin effects suggest common rate-limiting step in vivo

Diabetes ◽  
1993 ◽  
Vol 42 (2) ◽  
pp. 296-306 ◽  
Author(s):  
D. C. Bradley ◽  
R. A. Poulin ◽  
R. N. Bergman
Keyword(s):  
Rate Limiting Step ◽  
Limiting Step ◽  
Rate Limiting

Cobalt/Lewis Acid Catalysis for Hydrocarbofunctionalization of Alkynes via Cooperative C–H Activation

2020 ◽  
Author(s):  
Chang-Sheng Wang ◽  
Sabrina Monaco ◽  
Anh Ngoc Thai ◽  
Md. Shafiqur Rahman ◽  
Chen Wang ◽  
...  
Keyword(s):  
Catalytic System ◽  
Lewis Acid ◽  
Hydrogen Transfer ◽  
Acid Catalysis ◽  
Rate Limiting Step ◽  
Site Selectivity ◽  
Set Up ◽  
Site Selective ◽  
First Time ◽  
Rate Limiting

A catalytic system comprised of a cobalt-diphosphine complex and a Lewis acid (LA) such as AlMe3 has been found to promote hydrocarbofunctionalization reactions of alkynes with Lewis basic and electron-deficient substrates such as formamides, pyridones, pyridines, and azole derivatives through site-selective C-H activation. Compared with known Ni/LA catalytic system for analogous transformations, the present catalytic system not only feature convenient set up using inexpensive and bench-stable precatalyst and ligand such as Co(acac)3 and 1,3-bis(diphenylphosphino)propane (dppp), but also display distinct site-selectivity toward C-H activation of pyridone and pyridine derivatives. In particular, a completely C4-selective alkenylation of pyridine has been achieved for the first time. Mechanistic stidies including DFT calculations on the Co/Al-catalyzed addition of formamide to alkyne have suggested that the reaction involves cleavage of the carbamoyl C-H bond as the rate-limiting step, which proceeds through a ligand-to-ligand hydrogen transfer (LLHT) mechanism leading to an alkyl(carbamoyl)cobalt intermediate.

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