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Summary  

Calorimetric determination of the total enthalpy changes (ΔH i) of guanidine-denatured lysozyme (Lys) during the adsorption with simultaneously refolding on the surface of hydrophobic interaction chromatography packings was carried out at 250.001C. The measured ΔH iin the circumstances should include the changes in the three fractions: adsorption, dehydration and molecular conformation. It was found that when the unfolded Lys molecules are adsorbed and refold on the surface, entropy-driving caused by the dehydration of Lys mainly dominates the foregoing process. The refolding enthalpies of Lys, ΔΔH iwere found to be 10~100 folds higher than that measured in usual solutions.</o:p>

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Journal of Thermal Analysis and Calorimetry
Authors: Alexandre Prado, Aline Moura, Rômulo Andrade, Igor Pescara, Valéria Ferreira, Elaine Faria, Augusto de Oliveira, Esmeralda Okino, and Luiz Zara

Abstract

Brazilian sawdust samples (Caryocar spp.; Manilkara spp.; and Tabebuia spp.) have been used for Cr(VI) adsorption from water. The series of adsorption isotherms were adjusted to modified Langmuir equation. Thermodynamic data of interactions were studied by the calorimetric titration of Cr(VI) in aqueous solution. All liquid/solid interface adsorptions were entalpically and entropically driven. These sawdust samples were also used to remove chromium from tannery wastewater. The application of Caryocar spp.; Manilkara spp.; and Tabebuia spp. reduced the amount of chromium from 2.11 ± 0.18 mg L−1 to 1.15 ± 0.10; 0.29 ± 0.02 and 0.26 ± 0.02 mg L−1, respectively.

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Abstract  

A simple method has been adopted to obtain an important information on the heterogeneous properties of materials studied, adsorbed liquid films and liquid-solid interactions. The method utilizes Q-TG mass loss and the first derivative Q-DTG mass loss curves with respect to temperature and time obtained during programmed liquid thermodesorption in quasi-isothermal conditions. The values of the adsorption capacity, total porosity of material, the value of active centers, desorption energy distribution and mesopore-size distribution functions obtained by this method are in good agreement with those estimated on the basis of independent methods. The theoretical and experimental results provided novel and unique data on the heterogeneity of solid surfaces, properties of liquid adsorbed films and thermal stability of the liquid/solid interfaces. This paper presents the more important results obtained so far in the studies the liquid/solid systems by means of the Paulik's classical and quasi-isothermal techniques.

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confined in the pores can by written: 1 where Δ T is the melting point depression, T 0 is the bulk melting temperature, γ ls is the surface tension of liquid–solid interface, ρ is the density, h is the specific enthalpy of melting, and d A /d V is

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where Δ T is the melting point depression, T 0 is the bulk melting temperature, γ ls is the surface tension of liquid solid interface, ρ is the density, h is the specific enthalpy of melting, and d A /d V is the curvature of the solid liquid

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