Kinetic and thermodynamic studies of the esterification of acidified oil catalyzed by sulfonated cation exchange resin

This study describes the kinetics and thermodynamics of the esterification of acidified oil with methanol catalyzed by sulfonated cation exchange resins（SCER）. The effects of the mass ratio of methanol to acidified oil,reaction temperature,and catalyst loading were studied to optimize the conditions for maximum conversion of free fatty acids（FFAs）. The results showed that the optimal conversion rate of FFAs was 91.87% at the mass ratio of methanol to acidified oil of 2.5：1.0,reaction temperature of 65.0 °C,catalyst loading of 5.0 g and reaction time of 8.0 h. The external and internal mass transfer resistances were negligible based on the experimental results and a pseudo-homogeneous kinetic model was proposed for the esterification. The activation energy and thermodynamic parameters including G,S and H were determined. The conversion rates of FFAs obtained from the established model were in good agreement with the experimental data.

Water solubility enhancements of PAHs by sodium castor oil sulfonate microemulsions

Water solubility enhancements of naphthalene(Naph), phenantherene(Phen) and pyrene(Py) in sodium castor oil sulfonate(SCOS) microemulsions were evaluated. The apparent solubilities of PAHs are linearly proportional to the concentrations of SCOS microemulsion, and the enhancement extent by SCOS solutions is greater than that by ordinary surfactants on the basis of weight solubilization ratio(WSR). The log K em values of Naph, Phen, and Py are 3 13, 4 44 and 5 01 respectively, which are about the same as the log K ow values. At 5000 mg/L of SCOS conccentration, the apparent solubilities are 8 80, 121, and 674 times as the intrinsic solubilities for Naph, Phen, and Py. The effects of inorganic ions and temperature on the solubilization of solutes are also investigated. The solubilization is improved with a moderate addition of Ca 2+ , Na +, NH + 4 and the mixture of Na +, K +, Ca 2+ , Mg 2+ and NH + 4. WSR values are enhanced by 22 0% for Naph, 23 4% for Phen, and 24 6% for Py with temperature increasing by 5℃. The results indicated that SCOS microemulsions improve the performance of the surfactant enhanced remediation(SER) of soil, by increasing solubilities of organic pollutants and reducing the level of surfactant pollution and remediation expenses.