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The solubilities of fluoxetine hydrochloride (FH) in pure solvents including methanol, ethanol, n-propanol, i-propanol, n-butanol, i-butanol, s-butanol, n-pentanol, i-pentanol, acetone, 2-butanone, cyclohexanone, acetonitrile, tetrahydrofuran, and chloroform and binary solvent mixtures (methanol + water) were determined by a static gravimetric method at temperatures ranging from 278.15 to 318.15 K under atmospheric pressure. Thermodynamic models including the modified Apelblat model, λh model, NRTL model, and Wilson model were chosen to fit the solubility data in neat solvents, and the CNIBS/R-K model, modified Jouyban−Acree model, NRTL model, and Wilson model were selected to correct the solubility data of FH in binary solvent mixtures. The NRTL model fitted the experimental data best among all the selected models in pure solvents, with RAD = 0.0013, rmsd = 0.000022, and the CNIBS/R-K model fitted best in the binary solvent mixtures of methanol + water (with RAD = 0.0133, rmsd = 0.000349). Finally, the dissolution properties (i.e., the dissolution enthalpy, entropy, and Gibbs energy changes) of FH were calculated based on the Wilson model. The experimental data for FH will provide significant guidance for optimization of the crystallization process.

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In this work, the normal contact stiffness of lubricated rough interface is evaluated theoretically by describing the lubricated rough interface as an equivalent thin layer. Layer parameters, including equivalent thickness and effective Young’s modulus, are used to characterize the normal contact stiffness by incorporating the contributions of asperity contact and lubricant contact simultaneously. On the basis of layer parameters, the normal contact stiffness of lubricated rough interface is obtained as a function of interfacial separation, surface topography, and properties of contacting solids and lubricants. Effects of surface topographies and lubricant types on the normal contact stiffness are investigated at varying interfacial separations and contact area fractions. The proportion of solid stiffness and lubricant stiffness from the total normal stiffness is also discussed. Numerical solutions reveal that the normal contact stiffness depends sensitively on the lubricant property at initial contact, whereas the influences of surface topographies become obvious with the decrement of interfacial separation or increment of contact area fraction. Comparisons between the predicted values of normal contact stiffness and experimental data for both dry interface and lubricated interface are presented to validate the rationality of the developed model.

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A new ionic liquid-magnetic graphene (IL-MG) composite was used as the adsorbent in magnetic dispersive solid-phase extraction to rapidly extract and isolate triazine herbicides from surface water. IL-MG was synthesized by a simple and time-saving one-pot strategy where the synthesis of magnetic FeO, the modification with an IL, and the reduction of graphene oxide to graphene were conducted at the same time. An IL was applied to enrich the interaction mechanism between IL-MG and analytes (π-π, hydrophobic interaction, and electrostatic interaction). Moreover, the IL and FeO nanoparticles acted as spacers, inserting between the layers of graphene to prevent the aggregation of graphene, which improved the adsorption ability because of the large specific surface area of IL-MG. The resultant IL-MG had hierarchical flake structures and showed a high adsorption capacity (8266.0-12 324.1 μg g) toward triazine herbicides. Under suitable conditions, the linearity for triazine herbicides was achieved in the range of 0.55-500 ng mL with a detection limit of 0.09-0.15 ng mL and a quantitation limit of 0.31-0.51 ng mL, and the enrichment factor was 83-fold, which indicated that the proposed method could be successfully applied for the determination of triazine herbicides in surface water.