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Enantiomers differ greatly in their pharmacological and toxicological activities, and chirality is closely correlated with many significant biological processes; the separation of racemates is of great importance. Compared with traditional chiral separation methods such as crystallization, chromatographic separation and kinetic enzyme resolution, use of solid-state enantioselective membranes has the advantages of low energy consumption, simple equipment, and sustainable operation. Therefore, they are more suitable for the needs of large-scale industrial production. Herein, we discuss the theoretical and experimental developments in the emerging field of solid-state chiral separation membranes, focusing on the fundamental mechanisms of chiral molecule transport. Moreover, we highlight the advantages and disadvantages of different types of chiral separation membranes and their potential functional characteristics. Finally, the future trends of solid-state enantioselective membranes are proposed in this review, and we hope to provide some helpful ideas for researchers in the area. [ABSTRACT FROM AUTHOR]

ABSTRACT: Simple, direct precipitation was used to synthesize green, renewable, biobased flame retardants. Copper phytate (Cu–Phyt), zinc phytate, aluminum phytate, and tin phytate (Sn–Phyt) were synthesized. Thermogravimetric analysis performed in N2 revealed that the metallic phytate (M–Phyt, where M is Cu, Zn, Al, or Sn) salts showed good charring. The limiting oxygen index (LOI), cone calorimetry (CONE) test data, tensile strength, and impact toughness were measured for flexible poly(vinyl chloride) (PVC) containing 15 wt % M–Phyt salts. The PVC/Sn–Phyt LOI rose from 24.9 to 30.3%, and the PVC/Sn–Phyt mechanical properties were on par with those of the pure PVC. The CONE test results indicate that PVC/Cu–Phyt showed the lowest total smoke production (TSP) and peak heat‐release rate (pHRR) among the samples. The TSP and pHRR of PVC/Cu–Phyt were 15.77 m2 and 181.77 kW/m2, respectively, 62.63 and 44.48% lower than those of the neat PVC. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46601. [ABSTRACT FROM AUTHOR]

A novel catalyst consisting of SnO2 supported by activated carbon spheres (ACS), referred to as “ACS@SnO2,” was demonstrated as being much more efficient than either ACS or SnO2 alone. As such, it is capable of improving the thermal stability and flame retardancy of flexible poly (vinyl chloride) (fPVC). The resulting ACS@SnO2 composite exhibits a higher reactivity and excellent stability due to the presence of evenly dispersed SnO2 particles attached to the ACS, as well as the high degree of graphitization of the ACS. Smoke suppression and the synergistic flame‐retardant effect of the ACS@SnO2 on the fPVC were thoroughly investigated by performing a cone calorimeter test and thermogravimetric analysis. The cone calorimeter test data reveal that the addition of the ACS@SnO2 greatly improved the flame retardancy of the fPVC, with 32% and 58.4% decreases in the peak heat release rate and smoke production rate, respectively. This is attributed to the formation of a continuous and compact protective layer and the synergistic effects of the ACS and SnO2 in promoting the ability of the fPVC to isolate heat and oxygen. Furthermore, the ACS@SnO2/fPVC composite produced greatly increased amounts of char residue, thereby attenuating the fire hazard presented by fPVC composites. [ABSTRACT FROM AUTHOR]

The major objective of this work is to study the speciation of iron impacted by water quality including dissolved oxygen (DO), pH, alkalinity, sulfate, chloride, and monochloramine and the development of iron corrosion scales in drinking water distribution systems. Alkalinity, pH, and monochloramine had significant impacts on iron oxidation rate, and suspended iron particle, and DO, sulfate, and chloride had a slight effect on iron oxidation rate and suspended iron particle. Except at low pH, the oxygenation process of ferrous iron to ferric iron can be well described by oxidation kinetics model which also fits the monochloramine oxidation reaction. In the initial experiment stage with pipe corrosion scales having been destroyed and the iron being released seriously, the newly formed free and amorphous iron contents increased, instable iron compound dominated the iron corrosion scales and the mass fraction of the total iron in iron corrosion scales rose. With the iron release amount being relatively stable, the free and amorphous iron contents dropped, magnetite and goethite were the main components of iron corrosion scales, and the total iron in iron corrosion scales decreased. [ABSTRACT FROM PUBLISHER]

This study focused on the adsorptive behaviors of humic acid onto freshly prepared hydrous MnO2(s) (δMnO2), and investigated the feasibility of employing δMnO2 for humic acid removal from drinking water. Effects of such parameters as molecular mass of humic acid, kinds of divalent cations on adsorptive behaviors and possible mechanisms involved were investigated. This study indicated that humic acid with higher molecular mass exhibited more tendency of adsorbing onto δMnO2 than that with lower molecular mass. Ca2+ facilitated more humic acid adsorption than Mg2+; UV-Vis spectra analysis indicated higher capabilities of Ca2+ coordinating with acidic functional groups of humic acid than that of Mg2+. Additionally, ζ potential characterization indicated that Ca2+ showed higher potential of increasing gz potential of δMnO2 than Mg2+. Ca2+ of 1.0 mmol/L increased ζ potential of δMnO2 from −37 mV (pH 7.9) to +7 mV (pH 7.2), while 1.0 mmol/L Mg2+ increased to lower value as −9 mV (pH 6.5), correspondingly. Fourier transform infrared (FTIR) spectra demonstrated the adsorption of humic acid onto δMnO2, showing the important roles of-COO− functional groups and surface Mn-OH in the adsorption of humic acid onto δMnO2. [ABSTRACT FROM AUTHOR]