Examination of the Approximations Used in Determining the Isosteric Heat of Adsorption from the Clausius−Clapeyron Equation

Langmuir ◽  
1998 ◽  
Vol 14 (21) ◽  
pp. 6323-6327 ◽  
Author(s):  
Huanhua Pan ◽  
James A. Ritter ◽  
Perla B. Balbuena
Keyword(s):  
Isosteric Heat ◽  
Heat Of Adsorption ◽  
Clapeyron Equation ◽  
Isosteric Heat Of Adsorption

Adsorption Mechanism of Sodium Dodecyl Sulfate on Coagulating Precipitate in Treatment of Vat Dark Blue BO by Coagulation and Air-Flotation

2014 ◽  
Vol 1033-1034 ◽  
pp. 364-368
Author(s):  
Hong Yun Xia ◽  
Chang Qun Duan ◽  
Wei Zhang ◽  
Ke Diao He
Keyword(s):  
Sodium Dodecyl Sulfate ◽  
Sodium Dodecyl ◽  
Isosteric Heat ◽  
Heat Of Adsorption ◽  
Surface Loading ◽  
Clapeyron Equation ◽  
Isosteric Heat Of Adsorption ◽  
Heat Of Sorption ◽  
Dodecyl Sulfate ◽  
Dark Blue

Vat dark blue BO simulated wastewater was treated by Dissovled air flolation (DAF), the interaction of sodium dodecyl sulfate (SDS) and precipitate in the DAF process was investigated by thermodynamic methods. The adsorption isotherms of SDS on precipitate at pH 5.00 were determined at 30,35,40 and 45°C. The isosteric heat of sorption was calculated by the Clausius-Clapeyron equation. The results show that the isotherm of SDS on coagulation precipitate is not the normal style, the adsorption of SDS on precipitate is exothermic in nature and the isosteric heat of adsorption decreases with a increase in the equilibrium uptake of SDS on precipitate. The isosteric heat of sorption varies between-16.266 and-21.719kJ/mol as surface loading is between 3 and 11 mg/g. The values of isosteric heat of adsorption proves the primary adsorption of SDS on precipitation is physisorption.

The Isosteric Heat of Adsorption of Sr2+, Ce3+, Sm3+, Gd3+, Th4+ and UO22+ Ions on Activated Charcoal

1994 ◽  
Vol 11 (4) ◽  
pp. 201-208 ◽  
Author(s):  
Riaz Qadeer ◽  
Javed Hanif
Keyword(s):  
Activation Energy ◽  
Activated Charcoal ◽  
Physical Adsorption ◽  
Isosteric Heat ◽  
Heat Of Adsorption ◽  
Clapeyron Equation ◽  
Temperature Changes ◽  
Isosteric Heat Of Adsorption ◽  
Adsorption Processes ◽  
Increasing Temperature

The values of the isosteric heat of adsorption (qst) of Sr2+, Ce3+, Sm3+, Gd3+, Th4+ and UO22+ ions on activated charcoal have been calculated at different surface coverages and temperatures by applying the Clausius–Clapeyron equation. The variation of qst with surface coverage indicates the heterogeneous nature with varying activities of the activated charcoal surface. The behaviour of qst values with temperature suggests that two types of adsorption processes occur simultaneously; one with a small activation energy and the other with a large activation energy. A large increase in the qst values indicates that increasing temperature changes the physical adsorption process to chemisorption.

scholarly journals Experimental studies on equilibrium adsorption isosteres and determination of the thermodynamic quantities of polar media on alumina Al2O3

2017 ◽  
Vol 4 (1) ◽  
pp. 34-45 ◽  
Author(s):  
Albena Yonova
Keyword(s):  
Active Sites ◽  
Adsorption Process ◽  
Surface Acidity ◽  
Experimental Studies ◽  
Isosteric Heat ◽  
Heat Of Adsorption ◽  
Equilibrium Adsorption ◽  
Thermodynamic Quantities ◽  
Isosteric Heat Of Adsorption ◽  
Adsorption Isosteres

Abstract The present work is a revieif of theoretical and experimental study on the adsorption performance of the adsorbent Alumina (Al2O3) used in the adsorption system. An experimental investigation on the equilibrium adsorption isosteres at low pressure (< 1 atm) of working pairs Al2O3/H2O and Al2O3/C2H6O2 is carried out. The isovolume measurement method is adopted in the test setup to directly measure the saturated vapor pressures of working pairs at vapor-liquid equilibrium (dG=0 and dμi=0). Quantity adsorbed is determined from pressure, volume and temperature using gas law. The isosteric heat of adsorption is calculated from the slope of the plot of lnP versus 1/T different amounts of adsorbate onto adsorbent as follows: 0,01 vol% Al2O3/H2O; 0,03 vol% Al2O3/H2O; 0,1 vol% Al2O3/H2O; 0,01 vol% Al2O3/C2H6O2; 0,03 vol% Al2O3/C2H6O2; 0,1 vol% Al2O3/C2H6O2. This study shows that adsorption working pair Al2O3 C2H6O2 has better adsorption performances than those of the A2O3/H2O. Surface acidity! is a most important property! far both adsorption and catalysis and therefore is examined structure of active sites of alumina surface. Thermodynamic parameters such as isosteric heat of adsorption, isosteric enthalpy and entropy of adsorption are critical design variables in estimating the performance and predicting the mechanism of an adsorption process and are also one of the basic requirements for the characterization and optimization of an adsorption process

Intriguing differences in hydrogen adsorption in CPO-27 materials induced by metal substitution

2015 ◽  
Vol 3 (9) ◽  
pp. 4827-4839 ◽  
Author(s):  
Mali H. Rosnes ◽  
Martin Opitz ◽  
Matthias Frontzek ◽  
Wiebke Lohstroh ◽  
Jan Peter Embs ◽  
...  
Keyword(s):  
Comparative Study ◽  
Gas Adsorption ◽  
Hydrogen Adsorption ◽  
Isosteric Heat ◽  
Heat Of Adsorption ◽  
Hydrogen Gas ◽  
The Other ◽  
Metal Substitution ◽  
Isosteric Heat Of Adsorption ◽  
Open Metal Sites

We present a comparative study of hydrogen gas adsorption experiments on CPO-27–Cu and –Mn. The initial isosteric heat of adsorption in CPO-27–Cu is low for a material containing open metal sites and in contrast to the other members of the CPO-27 series, including the Mn compound.

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