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Thermodynamic parameters

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Isothermal compressibility and isobaric thermal shrinkage of a porous α-alumina compact: Thermodynamic calculations

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Isothermal compressibility and isobaric thermal shrinkage of a porous α -alumina compact: thermodynamic calculations. Abstract: Two methods were proposed to calculate the thermodynamic parameters of porous ceramic compacts de- pending on their molar volume change with applied pressure and heating temperature, respectively.

Spectroscopic and thermodynamic approach to the interaction of nonperipherally substituted cationic phthalocyanines with calf thymus (CT)-DNA

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To investigate the spontaneity of the reactions between DNA and novel quaternized phthalocyanines in buffer, thermodynamic parameters were employed.. 11 − 14 Even though most of the water-soluble Pcs dimerize and aggregate in aqueous solution, there are nonaggregated Pcs in the literature. 33 − 37 From this point of view, the aim of the present study was to synthesize novel nonperipherally tetrasubstituted quaternized metal-free (1Q), zinc (2Q), and indium (3Q) Pcs appending 2-morpholinoethoxy groups

Removal of Pb(II) and Cd(II) from aqueous solution using alkaline-modified pumice stone powder (PSP): Equilibrium, kinetic, and thermodynamic studies

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To understand the thermodynamic behaviour of the M(II) adsorption onto PSP, thermodynamic parameters such as standard Gibb’s free energy change ( ∆G. where R is the ideal gas constant, T is the temperature (K), and K c is the thermodynamic equilibrium constant.. q e is the equilibrium amount of M(II) adsorbed (mg L − 1 ) and C e is the concentration of M(II) ions in solution at equilibrium.

Synthesis, characterization, and metal extraction studies of a new macrobicyclic ligand

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This situation is mostly attributed to the replacement of some water molecules with a positively charged species in the macrocyclic cavity. 12,32,33 The negative values of thermodynamic parameters indicate that the formation of complex during solvent extraction is an exothermic process and occurs in a more ordered state.. Thermodynamic parameters for extraction process of Ag + ion on macrobicyclic ligand 3..

The effects of ionic strength and temperature on the dissociation constants of adefovir and cidofovir used as antiviral drugs

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The effects of temperature on the dissociation constants of PMEA and HPMPC were studied at 0.1 mol dm − 3 ionic strength (NaCl) and, according to the obtained data, thermodynamic parameters ( ∆H , ∆S , and ∆G) were calculated for 298 K, 308 K, and 318 K temperatures. These results could be of considerable assistance for advancing understanding of the drugs’ behavior in vivo.. Thermodynamic functions of PMEA ( I : 0.1 mol dm − 3 NaCl)..

Calculation of Morse Potential Parameters of bcc Crystals and Application to Anharmonic Interatomic Effective Potential, Local Force Constant

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Anharmonic interatomic potentials including Morse potential parameters [1,2], have been intensively studied [1-17]. They are used for the calculation and analysis of the thermodynamic parameters, especially, the anharmonic effects contained in XAFS (X-ray Absorption Fine Structure) [10-15] which influence on the physical information taken from these spectra. Morse potential is an empirical potential [1,2] and their parameters are often extracted from experiment [16,17].

Comparative density functional study of antioxidative activity of the hydroxybenzoic acids and their anions

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The values of the thermodynamic parameters BDE, PA, and PDE (Table 2) indicate that the p-OH group should be a more reactive site in all solvents, meaning that the p-HBA anion is slightly better at radical scavenging than the other two..

Isotherms, thermodynamics and kinetics of rhodamine B dye adsorption on natural diatomite

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Isotherm parameters for adsorption of RB dye onto the diatomite. Langmuir plots for adsorption of RB onto the diatomite at 30 o C (a) and 45 o C (b) Based on the adsorption constant in the Langmuir isotherm (K L. thermodynamic parameters (G o , H o and S o ) for adsorption of RB onto PYD were calculated using Eqs.. (9) [5, 7] and the results were given in Table 2.

Sorption studies of europium on cerium phosphate using Box-Behnken design

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Thermodynamic data provides information about the spontaneity of the sorption process. T is the temperature (K), V is the solution volume (mL) and m is the mass (g) of the sorbent. H o and ∆ S o were calculated from the slope and intercept of the plot between InK D and 1/T.. Thermodynamic parameters for Eu(III) sorption are given in Table 6. The negative values of ∆ G o obtained at and 333 K point out the spontaneity of the Eu(III) sorption process..

High – order anharmonic effective potentials and EXAFS cumulants of Nickel crystal by quantum perturbation theory

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Keywords : EXAFS cumulants;. technique for providing information on the local atomic structure and thermodynamic parameters of the substances [5, 6]. At any temperature the position of the atoms and interatomic distances are changed by thermal vibrations. For a two-atomic molecule, the EXAFS cumulants can be expressed as a function of the force constant of the one.

Impact of surface modification of green algal biomass by phosphorylation on the removal of copper(II) ions from water

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This result confirms the endothermic nature of the adsorption of Cu +2 ions onto the algal biomass. (13) through (15) were used to calculate the thermodynamic parameters for the adsorption process.. This behavior confirms the feasibility of the adsorption process if a low Cu +2 ion initial concentration is used.. Table 4 shows the values of the thermodynamic parameters for Cu +2 ions’ adsorption onto the algal biomass at different initial concentrations with temperatures from 30 to 50 ◦ C.

Structural and adsorption behaviour of ZnO/aminated SWCNT-COOH for malachite green removal: Face-centred central composite design

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Table 6 indicated the thermodynamic parameters for MG adsorption onto ZnO/aminated SWCNT-COOH. The ΔS o of ZnO/aminated SWCNT-COOH adsorbing MG dye was higher than 0, which means that the disorder of adsorption process. Furthermore, the structure elucidation of the adsorbent was determined using various characterization techniques such as FTIR, XRD, and SEM-EDX. The surface shape of the nanocomposite was nanoflower..

Anharmonic effective potential and XAFS cumulants for hcp crystals containing dopant atom

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For completing the ab initio calculation procedure the parameters of Morse potential of pure crystals and those with dopant have been also calculated. Numerical calculations for Zn doped by Cd atom have been carried out to show the thermodynamical effects of hcp crystal under influence of the doping atom. The calculated results are found to be in good agreement with experiment for Morse potential and for the other thermodynamic parameters [13]..

Novel bis(aminoalcohol)oxalamide organogelators and their diglycolylamide analogs: Evaluation of gelation efficiency in various organic fluids

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Furthermore, van’t Hoff relationships were employed to obtain thermodynamic parameters for gel-to-sol transitions in order to analyze the detailed thermal behaviors of the gels. This could also apply to obtaining the gel-sol transition enthalpy. Enthalpies of the gel-sol transition ( ∆H gel. obtained from the slope of van’t Hoff plots for gels of and 8 in anisole are summarized in Table 3 and represented in Figure 3..

Parameterization, kinetics, and adsorption isotherm of electrocoagulation process of bromothymol blue in aqueous medium using aluminum electrodes

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Some parameters of the linear regression of Freundlich and Langmuir isotherms for the EC of BTB in aqueous solution.. G) for the EC process was calculated using the expression in Eq. G is the free energy (kJ/mol), K is the equilibrium constant, R is the gas constant, and T is the absolute temperature.. The values of the thermodynamic parameters K and ∆ G are presented in Table 2.

Synthesis, characterization, and kinetic studies of multifunctionalized mesoporous silica for adsorption of zinc

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The adsorption properties and thermodynamic parameters of the bifunctional mesoporous silica synthesized to adsorb Zn(II) ions were studied.

Synthesis and characterization of novel 4-benzyloxyphenyl 4-[4-(n-dodecyloxy) benzoyloxy]benzoate liquid crystal

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IGC was used for studying the thermodynamic parameters of BDBB. of BDBB.. The weight fraction activity coefficients at infinite dilution of the solvents, Ω 1. IGC is an appropriate analysis for the examination of the thermodynamic properties of LCs.. The values of the partial molar heat of sorption, ΔH– S (kcal mol −1. of the studied solvents, and the literature values of the molar heat of vaporization, ΔH– VL (kcal mol −1 ) [29].. Introduction to Liquid Crystals Chemistry and Physics.

Correlation Effects in Atomic Thermal Vibration of fcc Crystals

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D and α are the parameters of the Morse potential. and the other parameters have been defined as follows. Using the quantum statistical method, where we have used the statistical density matrix Z and the unperturbed canonical partition function ρ 0. In the crystal each atom vibrates in the relation to the others so that the correlation must be included. In the HT limit we use the approximation. to simplify the expressions of the thermodynamic parameters. In the LT limit.

Studies using extracts of green tea as a corrosion inhibitor for CT38 steel in 0.01m HCL solution

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Thermodynamic consideration reveals that adsorption of Green tea extract on mild steel surface is spontaneous and occurs according to Langmuir adsorption isotherm. Physical adsorption mechanism has been proposed for the adsorption of the inhibitor from the values of some kinetic and thermodynamic parameters.. Key words: Corrosion inhibition, mild steel, Langmuir adsorption isotherm, physical adsorption, green tea.

Effect of pH and β -cyclodextrin on the photophysical properties of lamotrigine

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Table 2 also shows that complex formation of LMT with β -CD at pH 2.0 and 8.0 has negative entropy change ( ∆S. β -CD and –4.5 J mol − 1 K − 1 for LMT/ β -CD), which can be attributed to the limit of the β -CD cavity to the translational and rotational degrees of freedom of the guest molecule. 21,22,27 Our thermodynamic results are in good agreement with the theoretically calculated thermodynamic parameters of LMT/β -CD gas-phase complexation obtained by Seridi and Boufelfel.