Adsorption of organics on thermally treated solids obtained from colloidal silica

1987 ◽  
Vol 52 (3) ◽  
pp. 572-581 ◽  
Author(s):  
Miroslav M. Kopečni ◽  
Slobodan K. Milonjic ◽  
Wladyslaw Rudzinski ◽  
Jacek Jagiello
Keyword(s):  
Gas Chromatography ◽  
Thermodynamic Parameters ◽  
Adsorption Isotherms ◽  
Colloidal Silica ◽  
Adsorption Properties ◽  
Thermal Pretreatment ◽  
Lateral Interactions ◽  
Adsorbed Molecules ◽  
Temperature Range ◽  
Thermally Treated

Adsorption isotherms of three adsorbates on the solid beads obtained from colloidal silica were determined by means of gas chromatography at low surface coverages, when lateral interactions between the adsorbed molecules are negligible. The influence of thermal pretreatment on the adsorption properties of the solids was investigated in the temperature range from 343 to 423 K, while the solids were heated between 523 K and 1 223 K. The thermodynamic parameters of adsorption have been determined and used to discuss the adsorbate-adsorbent interactions.

Adsorption of noble gases on the carbon adsorbents supersorbon HS and Jado

1983 ◽  
Vol 48 (3) ◽  
pp. 819-826 ◽  
Author(s):  
Ludmila Wilhelmová ◽  
František Cejnar
Keyword(s):  
Gas Chromatography ◽  
Active Carbon ◽  
Noble Gases ◽  
Carbon Adsorbent ◽  
Adsorption Properties ◽  
Carbon Adsorbents ◽  
Adsorption Behaviour ◽  
Practical Application ◽  
Heats Of Adsorption ◽  
Temperature Range

The isotherms, isosters and heats of adsorption of argon, krypton and xenon were measured on the active carbon Supersorbon HS and the carbon adsorbent Jado LD 1191 - in a temperature range 298-473 K, using gas chromatography. Differences were observed in the adsorption behaviour of both types of adsorbents - which showed especially on the nonlinearity of adsorption isosters of all gases studied with the Jado LD 1191 adsorbent. It was found that both types of adsorbents possess good adsorption properties, which can be - for Supersorb HS - utilized in the beds of the delaying lines of radioactive noble gases. The practical application of the Jado LD 1191 adsorbent for the same purposes is limited by the presence of inactive teflon support in the structure of this adsorbent.

Polymerization of acrylonitrile initiated by peroxomonosulphate-thiols redox systems

1990 ◽  
Vol 55 (8) ◽  
pp. 2001-2007
Author(s):  
Gurusamy Manivannan ◽  
Pichai Maruthamuthu
Keyword(s):  
Ionic Strength ◽  
Thermodynamic Parameters ◽  
Thermal Polymerization ◽  
Reaction Scheme ◽  
Degree Of Polymerization ◽  
Reducing Agent ◽  
Redox Systems ◽  
Temperature Range ◽  
Rate Of Polymerization

Aqueous thermal polymerization of acrylonitrile (AN) initiated by peroxomonosulphate (HSO5-, PMS)-thiolactic acid (TLA) and PMS-thiomalic acid (TMA) redox systems has been carried out in the temperature range 30-50 °C. The effect of concentration of monomer, initiator, reducing agent, H+, and ionic strength on rate of polymerization, Rp, has been investigated under deaerated conditions. The Rp has been found to depend on, Rp ~ [AN]01.5 [PMS]0.5 [TLA]0.5 in PMS-TLA system and, Rp ~ [AN]02.0 [PMS]1.0 [TMA]0 in PMS-TMA system. The degree of polymerization (Xn) values and thermodynamic parameters have been evaluated. Suitable reaction scheme has been proposed and expressions for Rp and Xn have been obtained.

Extending the upper temperature range of gas chromatography with all-silicon microchip columns using a heater/clamp assembly

2017 ◽  
Vol 1517 ◽  
pp. 134-141 ◽  
Author(s):  
Abhijit Ghosh ◽  
Jacob E. Johnson ◽  
Johnathan G. Nuss ◽  
Brittany A. Stark ◽  
Aaron R. Hawkins ◽  
...  
Keyword(s):  
Gas Chromatography ◽  
Temperature Range ◽  
Silicon Microchip

Thermochromism of Metal Exchange Reaction between Zinc(II) and Mercury(II) Porphyrins

1995 ◽  
Vol 50 (4) ◽  
pp. 545-550 ◽  
Author(s):  
Masaaki Tabata ◽  
Masahiro Ide ◽  
Kentaro Kaneko
Keyword(s):  
Aqueous Solution ◽  
Exchange Reaction ◽  
Thermodynamic Parameters ◽  
Distribution Curve ◽  
Equilibrium Constants ◽  
Metal Exchange ◽  
Free Base ◽  
Temperature Range ◽  
Base Form ◽  
Metal Exchange Reaction

Thermochromism was observed for an aqueous solution containing zinc(II) and mercury( II) cations and N-p-nitrobenzyl-5,10,15,20-tetrakis(4-sulfonatophenyl)porphyrin anion (NO2Bz(Htpps)4-) in the temperature range 10 to 70 °C. The equilibrium constants and the thermodynamic parameters of Zn(NO2Bztpps)3- and Hg(NO2Bztpps)3- have been determined spectrophotometrically to elucidate the thermochromism at 10, 15, 20, 25 and 30 °C in 0.1 mol dm-3 NaNO3. The protonation and metalation constants of NO2Bz(Htpps)4- are defined as K2 = [H2P][H+]-1[HP]-1, K3 = [H3P][H+]-1[H2P]-1 and KMP = [M P][H+][M2+]-1[HP]-1, where HP and MP denote the free base form of the prophyrin and the metalloporphyrins of zinc(II) and mercury(II), respectively. Charges of the prophyrin and metalloporphyrins are omitted for simplicity. The following values were found: logK2 = 7.75 ±0.02 (25 °C), ΔH°/kJmol-1 = -21.2±0.5 and ΔS°/Jmol-1K-1 = 77±1, logK3 = 2.55±0.02 (25 °C), ΔH°/kJmol-1 = -25±0.8 and ΔS°/Jmol-1K-1 = -35±3 and log KZnP = 0.63±0.03 (25 °C), ΔH°/kJmol-1 = 31.0±0.8 and ΔS°/Jmol-1K-1 = 116±3, logKHgP = 6.22±0.03 (25 °C), ΔH°/kJmol-1 = 4.5±0.7 and ΔS°/Jmol-1K-1 = 134±2. The distribution curve calculated from the thermodynamic parameters sufficiently agrees with the observed metal exchange reaction between the metalloporphyrins.

Adsorption properties of a Pd/γ-Al2O3 catalyst using inverse gas chromatography

2004 ◽  
Vol 70 (1-3) ◽  
pp. 109-118 ◽  
Author(s):  
Eva Dı́az ◽  
Salvador Ordóñez ◽  
Aurelio Vega ◽  
José Coca
Keyword(s):  
Gas Chromatography ◽  
Inverse Gas Chromatography ◽  
Adsorption Properties ◽  
Al2o3 Catalyst

Adsorption properties of CH4 and CO2 in quartz nanopores studied by molecular simulation

RSC Advances ◽  
2016 ◽  
Vol 6 (39) ◽  
pp. 32770-32778 ◽  
Author(s):  
Haoyang Sun ◽  
Wenchao Sun ◽  
Hui Zhao ◽  
Yange Sun ◽  
Dianrui Zhang ◽  
...  
Keyword(s):  
Molecular Simulation ◽  
Binary Mixtures ◽  
Adsorption Isotherms ◽  
Competitive Adsorption ◽  
Adsorption Properties ◽  
Density Distributions ◽  
Adsorption Density ◽  
Surface Hydroxylation

Competitive adsorption isotherms and adsorption density distributions of binary mixtures containing CH4 and CO2 in nanopores with 100% and 60% surface hydroxylation at 323 K.

scholarly journals Parameters Expediting the Thermal Conversion of Ba-Exchanged Zeolite A to Monoclinic Celsian

2010 ◽  
Vol 2010 ◽  
pp. 1-8 ◽  
Author(s):  
A. Marocco ◽  
M. Pansini ◽  
G. Dell'Agli ◽  
S. Esposito
Keyword(s):  
Phase Transition ◽  
Amorphous Phase ◽  
Room Temperature ◽  
Thermal Conversion ◽  
Zeolite A ◽  
Thermal Transformations ◽  
Final Phase ◽  
Temperature Range ◽  
Thermally Treated

Four samples of Ba-exchanged zeolite A, bearing small residual amounts of Na (0.27, 0.43, 0.58, and 0.74 meq/g), were thermally treated in the temperature range 200–1500∘C for times up to 28 hours. The same samples were pressed at 30 and 60 MPa to form cylindrical pellets which were thermally treated at 1300∘C for 5 hours. All materials were characterized by room temperature XRD. The sequence of thermal transformations that Ba-exchanged zeolite A undergoes (zeolite → amorphous phase → hexacelsian → monoclinic celsian) and the strong mineralizing action developed by Na are confirmed. Pressing the Ba-exchanged zeolite A powder-like samples to obtain cylindrical pellets is found to expedite the sluggish final phase transition hexacelsian → monoclinic celsian. The optimum residual Na content of Ba-exchanged zeolite A for transformation into monoclinic celsian is assessed to be between 0.27 and 0.43 meq/g.

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