In this work, an equation of state has been utilized for thermodynamic modeling of aqueous ionic liquid (IL) solutions. The proposed equation of state is a combination of perturbed chain statistical associating fluid theory (PC-SAFT) equation of state and mean spherical approximation (MSA) term. In this model, the ion-based approach has been used to adjust the model parameters. The ion parameters have been estimated through simultaneous fitting to experimental mean ionic activity coefficient and liquid density data of strong electrolytes. Using adjusted ion parameters, osmotic coefficients, mean ionic activity coefficients, liquid densities, apparent molar volume, and water activity of several ILs, assumed as chainlike electrolytes, have been calculated. Results show that PC-SAFT, in combination with the MSA term has acceptable accuracy for prediction of density, apparent molar volume, and activity coefficient of ILs. The average deviations of predicted mean ionic activity coefficients, liquid densities, water activity, and apparent molar volume are 6.43, 0.86, 0.033, and 8.20%, respectively.

In this study, a predictive model is presented for estimation of second order thermodynamic properties of electrolyte solutions. In order to provide a comprehensive understanding, the capability of modified electrolyte PC‐SAFT up to high pressure and temperature has been studied. In addition to the first order derivative thermodynamic properties, the Gibbs free energy, enthalpy and heat capacity of aqueous electrolyte solutions at infinite dilution are predicted. Using new methodology, the dielectric constant is modified to keep the pressure, temperature, and ionic strength dependency. Our results show that the Born term has a significant contribution on prediction of second order derivative properties. Meanwhile the impact of temperature‐dependent solution dielectric constant on standard state heat capacity is studied. Finally, the isobaric heat capacity at various salt concentrations is predicted without any adjustable parameters. The results of this work indicate an acceptable agreement with experimental data especially at high pressure and temperature. © 2017 American Institute of Chemical Engineers AIChE J, 2017

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In this study, thermodynamic modeling of mixtures including heterocyclic compounds using the perturbed chain statistical associating fluid theory (PC-SAFT) equation of state (EoS) is studied. The oxygen-, nitrogen-, or sulfur-containing heterocyclic molecules are modeled as nonassociating components. For some more aggregative associating compounds with −OH (furfuryl alcohol, tetrahydrofurfuryl alcohol, 2-thiophenemethanol, and 5-hydroxymethylfurfural) or −NH (azetidine, aziridine, pyrrole, pyrazole, pyrrolidine, pyrrolidone, piperidine, morpholine, imidazole, piperazine, and n-methylpiperazine) groups, two association sites are considered for each molecule. The pure component parameters of the PC-SAFT EoS are adjusted to vapor pressure and liquid density experimental data with average absolute relative deviation of 0.88 and 0.77%, respectively. Using the obtained parameters, the isobaric and isothermal phase behavior of binary systems is studied over a wide range of thermodynamic conditions. The average deviations between model calculations and experimental data for heterocycle + aromatics, heterocycle + cycloalkane, heterocycle + haloalkanes, heterocycle + alcohol, heterocycle + heterocycle, heterocycle + organic solvents, and heterocycle + hydrocarbon systems are about 1.79, 2.15, 1.03, 1.68, 2.81, 1.24, and 1.81% respectively. Furthermore, the solid–liquid equilibria of heterocycle mixtures have been predicted by estimation of melting and eutectic points over a wide range of compositions. The second-order-derivative thermodynamic properties of heterocyclic compounds including speed of sound (u s) and heat capacity (C p) have been also predicted. The obtained results are in good agreement with the experimental data.

Background: Nowadays, the demand for antibacterial fabrics has increased. White alum is used for oral aphthous ulcers treatment in traditional medicine of Sistan city, Sistan and Baluchistan Province, Iran, and also as a flocculent for water purification. This study is aimed to evaluate the effect of concentration and time on antibacterial activity of white alum on Escherichia coli O157:H7. Materials and Methods: 0.25, 0.5, 1 and 2% concentrations of white alum were added to 10 8 CFU of Escherichia coli O157:H7. Optical Density was recorded for 4 hours. Data obtained were analyzed using Repeated Measure and Oneway ANOVA by SPSS. Results: Results revealed the effectiveness of white alum in the growth of the tested bacterium. The white alum was found to be potent against Escherichia coli O157:H7 at a concentration above 1% (p<0.05). Also, its effect is dose and time dependent, as well as other disinfectants. Conclusion: A wide variety of natural products has been under scrutiny for their clinical potential, both in terms of prevention and treatment. Strong antibacterial activity of white alum compared with control was shown against tested bacterium. In conclusion, white alum can be used as an inhibitor of bacterial growth, especially for Escherichia coli O157:H7.

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