The solubilities of decahydropyrazino[2,3-b]pyrazine (DHPP) in methanol, ethanol, and 2-propanol were measured at temperatures ranging from 274.95 to 354.75 K. The last crystal disappearance method was used to determine the solubility of DHPP. The experimental data were correlated by the van’t Hoff plot, λh (Buchowski) equation, modified Apelblat equation, and two local composition models (Wilson and NRTL). Moreover, the densities of (DHPP + water) solution were measured from 274.25 to 355.95 K, and the liquid molar volume of DHPP, V m1(T), was obtained and used to calculate the parameters in the Wilson model. It was found that NRTL model gave the best correlation results. On the basis of the NRTL model and experimental data, the thermodynamic excess functions (ΔG E, ΔS E, and ΔH E) of DHPP + alcohols (methanol, ethanol, and 2-propanol) systems were determined. Furthermore, the infinite-dilution activity coefficient and the infinite-dilution reduced excess enthalpy (γ1 ∞ and ΔH E1 ∞) were derived.

The solubilities of lauric acid in methanol, ethanol, propanol, n-butanol, n-pentanol, n-hexanol, isobutanol, and isoamylol were measured by synthetic method in the temperature ranging from (276.17 to 306.12) K. Results of these measurements were correlated by the modified Apelblat equation, the λh equation and activity coefficient models (NRTL and UNIQUAC). It was found that the modified Apelblat equation and the λh equation gave better correlation results. The thermodynamic properties of the solution process, including the Gibbs energy, enthalpy, and entropy were calculated by the van't Hoff analysis.

The solubilities of pentachloropyridine (PCP) and tetrachloropyridine (TECP) in methanol, ethanol, and 2-propanol were measured respectively using an analytical method from (293.15 to 355.15) K. From the thermodynamics theory of solid-liquid equilibrium, the solubility model was derived, and the experimental data were regressed. The average deviation of the model was smaller than 5 %. The fusion enthalpies (∆ fus H) of PCP, TECP, and their infinite-dilution activity coefficientes (γ 2 ∞ ) in methanol, ethanol, and 2-propanol were obtained by regressing the experimental data.

The thin-film composite (TFC) nanofiltration (NF) membrane is a very important method in solving the water crisis. However, the fabrication and industrialization of high-performance NF membranes still remains challenging. In this work, zwitterionic NF membranes via microwave-assisted grafting of betaine was first proposed. The resulting polyamide layer showed leaflike nanostructures after modification. Because of the enlarged permeation area and enhanced hydrophilicity derived from the unique leaflike structure, the optimal membrane permeability reached 40.8 L m −1 h −1 bar −1 . This water permeance was 2.2 times as high as the original polypiperazine-amide membrane, with a Na 2 SO 4 rejection maintained at 97.0%. More importantly, the membrane demonstrated excellent selectivity to monovalent and divalent anions. This zwitterionic membrane fabricated by microwave-assisted grafting of betaine provides new insight for industrial scalable NF membranes with great potentials.