Phase equilibria for the pseudo-ternary system(NaCl+Na2SO4+H2O)of coal gasification wastewater at T=(268.15 to 373.15)K

The pseudo-ternary system(Na Cl + Na_2SO_4+ H_2O) of coal gasification wastewater was studied at T =(268.15 to 373.15) K. The solubility and density of the equilibrium liquid phase were determined by the isothermal solution saturation method. The equilibrium solids were also investigated by the Schreinemaker's method of wet residues and X-ray powder diffraction(XRD). According to the experimental data, the phase diagrams were determined. It was found that there was no significant solubility difference on the Na Cl-rich side between the ternary system(Na Cl + Na_2SO_4+ H_2O) in coal gasification wastewater and in pure water. However, the solubility on the Na_2SO_4-rich side of coal gasification wastewater was apparently higher than that of pure water. The increase in the solubility of Na_2SO_4 was most likely caused by the effects of other impurities apart from Na Cl and Na_2SO_4 in coal gasification wastewater. The measured data and phase equilibrium diagrams can provide fundamental basis for salt recovery in coal gasification wastewater.

基于过渡金属氧化物半导体上光电催化生产过氧化氢

作为一种有价值的化学品,过氧化氢广泛应用于工业领域.不仅如此,过氧化氢还具有比氢气更高的能量密度及优于传统化石燃料的环保优势,因此,其作为太阳能储能介质的应用也吸引了越来越多研究者的关注.传统蒽醌法生产过氧化氢存在需要贵金属催化剂、能耗大、碳排放高、过程繁琐、产物不纯、产生大量固液气废物等问题,因此,开发简便、环保、节能和安全的方法生产过氧化氢具有十分重要的意义.光电催化法结合了光催化和电催化方法的优势,可以有效提高能量转换效率并降低电能消耗,是具有潜力的生产过氧化氢新方法.同时,过渡金属氧化物半导体是光电催化法生产过氧化氢最有希望的催化剂材料.本综述简要介绍了光电催化法合成过氧化氢的基本原理,概述了光电催化反应合成过氧化氢的两种不同路径(水分子氧化和氧气还原)、相应的中间产物以及制备过氧化氢的三个主要过程(光吸收、光生电荷分离和表面反应),并总结了文献中各种测定过氧化氢浓度的方法.归纳了用于光电催化法生产过氧化氢的过渡金属氧化物半导体光电催化剂的最新进展,主要包括基于钒酸铋、二氧化钛、三氧化钨、氧化镍以及其他过渡金属氧化物的催化剂材料和反应体系,从理论计算和实验测定两个角度揭示了过渡金属氧化物催化剂材料在过氧化氢生产中的巨大潜力,总结了过渡金属氧化物的改性策略以进一步提高其活性和效率.本文还介绍了光电催化生产过氧化氢燃料电池的研究进展,展示了过氧化氢作为储存太阳能的可再生燃料的巨大潜力.最后,着重从催化剂光生电荷分离、活性位点、反应选择性、过氧化氢稳定性、电解质溶液和反应标准化测试六个方面讨论了光电催化法生产过氧化氢所面临的挑战和未来前景.综上,本文旨在为光电催化法生产可再生太阳能燃料过氧化氢提供启发.

Ternary phase diagrams and solvate transformation thermodynamics of omeprazole sodium in different solvent mixtures

Omeprazole sodium(OMS), a typical non-hydrogen bond donors API, is only available in solvates so far, including monohydrate, ethanol solvate and methanol solvate. The methanol solvate was found for the first time. Solvate transformation thermodynamics of OMS was studied in this paper. First, the ternary phase diagrams forming two solvates for OMS in binary solvent mixtures including methanol + water, ethanol + water, and methanol+ ethanol were measured at temperature ranging of T =(278.15 to 313.15) K under atmospheric pressure. Further, the standard equilibrium constants of the solvate transformation reactions were evaluated according to the chemical reaction isothermal equation. The standard molar Gibbs free energy, the standard molar enthalpy, and the standard molar entropy of solvate transformation reactions were then calculated based on van't Hoff equation. Moreover, the thermodynamic stability of the OMS solvate was analyzed based on phase diagram. The results are of great importance to develop a crystallization process for manufacturing OMS solvate, and could be helpful to other solvate transformation research.