Effects of additives on the phase transformation, occurrence state, and the interface of the Ti component in Ti-bearing blast furnace slag

The influences of additives on the phase transformation, occurrence state, and the interface of the Ti component in Ti-bearing blast furnace slag were investigated. After oxidation, most of the Ti component in the slag was enriched into the perovskite phase, which served as the Ti-rich phase during the crystallization process. The phase transformation, occurrence state, and the interface of the Ti component were observed to be affected by the addition of different types of agents. During the oxidation process, titanaugite and Ti-rich diopside phases gradually transformed into non-Ti phases（anorthite： CaMgSi2O6 and CaAl2Si2O8） in the form of dendrites or columns, which were observed to be distributed at the surface of the perovskite phase. Several more cracks appeared along the grain boundaries of the perovskite phase after the addition of P2O5, facilitating the liberation of the perovskite phase. Composite additives combining both an acid and a base, such as CaO ＋ CaF2 or P2O5 ＋ CaF2, were used. We observed that the disadvantages of using single additives were successfully overcome.

Novel additives for the separation of organic acids by ion-pair chromatography

This paper proposes the use of novel surfactant additives for the separation of organic acids by ion-pair chromatography and studies the influences of surfactants on the chromatographic separation behaviors.Researches have been carried out on both silica gel matrix and polymer supporters in order to compare the two ordinary kinds of stationary phases,and the phenomenon is similar. Separation is based on differences in the stabilities of analyte-additive complexes in solution.Retention times of analytes can ...

An Improved Method of Simultaneous Determination of Four Bioactive Compounds in Evodiae Fructus Using Ionic Liquids as Mobile Phase Additives in High Performance Liquid Chromatography

There are many compounds with different structures and chemical properties in Evodiae Fructus. It is hard to simultaneously determine the bioactive compounds by high performance liquid chromatography（HPLC）. A new method was proposed for four bioactive compounds（synephrine, limonoids, evodiamine and rutecarpine） to be separated completely and determined accurately using ionic liquids（ILs） as mobile phase additives. The mechanism and the effect of the ILs for changing the chromatographic behaviors of the four compounds were studied by systemati- cally changing the pH value of mobile phase, the types and concentrations of ILs as well as the concentrations of phosphate buffer. The chromatographic behaviors of the analytes with a mobile phase containing ILs complied with the stoichiometric displacement model for retention（SDM-R）. All results demonstrate the dual nature of ionic liquids, which are competitive adsorption and ion-pair agent. Meanwhile, excellent linearity was observed for all the com- pounds with correlation coefficients between 0.9992 and 0.9998. The limit of detection and the limit of quantification of the four compounds varied from 0.47μg/mL to 0.87 μg/mL and from 1.79 μg/mL to 2.44μg/mL, respectively. Three kinds of Evodiae Fructus processed through different methods were analyzed via the method. The result shows that the contents of evodiamine and rutecarpine as the two main active compounds by processing with vinegar and salt are obviously higher than those of the raw products.

Enantiomeric separations of four basic drugs containing N-alkyl groups by a RP-HPLC system using SBE-β-CD as chiral mobile phase additive

The chiral separations of four pharmaceutical racemates which contain N-alkyl groups were satisfactorily resolved using SBE-β-CD as a chiral mobile phase additive （CMPA） in a RP-HPLC system （the resolution is 2.701 for ondansetron hydrochloride, 1.996 for sulpiride, 1.293 for clenbuterol hydrochloride and 0.816 for omeprazole）. In addition, the effects of different parameters such as CD type and CD concentration were investigated. The separation mechanism arises through the combination of several potential interactions, including electrostatic interactions as well as hydrogen bonding interactions and hydrophobic inclusion interactions, which allow for the SBE-β-CD-drug complexation with strong stereoselectivity and stability. The resolution also relates to the number and location of N atoms in the enantiomers. This method will be applicable to the isolation of various types of biologically imoortant enantiomers containing N-alkyl groups.

Recent Advances on Chiral Mobile Phase Additives: A Critical Review

Chirality is one of the fundamental attributes of nature, which exists in different or even completely opposite metabolic,toxicological and pharmacological properties in organisms. Consequently, obtaining enantiomerically pure drugs or optically active intermediates is highly desired in many fields like medicine, food and biochemistry. Thereby, it also promoted the development of various enantiomer selective separation techniques. Among the many chiral separation methods, chiral mobile phase additives(CMPAs) are widely used in various chromatographic techniques due to their simple operation,good versatility and low price. There have been a number of reviews on the research progress of CMPAs in last 2 decades,but they only reviewed the application of CMPAs in one specific chromatographic technique. Therefore, to provide a more comprehensive illustration of CMPAs in separation technology, their applications in high-performance liquid chromatography, capillary electrophoresis, countercurrent chromatography, nano-liquid chromatography were summarized and their advantages and disadvantages were briefly introduced in this critical review. The application of molecular simulation in the study of chiral separation mechanism was briefly summarized. We expect that it will provide researchers with the latest developments in this field and potential inspirations.

Effect of non-solvent additives on the morphology,pore structure, and direct contact membrane distillation performance of PVDF-CTFE hydrophobic membranes

Four common types of additives for polymer membrane preparation including organic macromolecule and micromolecule additives, inorganic salts and acids, and the strong non-solvent H2 O were used to prepare poly（vinylidene fluoride-co-chlorotrifluoroethylene）（PVDF-CTFE） hydrophobic flat-sheet membranes. Membrane properties including morphology, porosity, hydrophobicity, pore size and pore distribution were investigated, and the permeability was evaluated via direct contact membrane distillation（DCMD） of 3.5 g/L Na Cl solution in a DCMD configuration. Both inorganic and organic micromolecule additives were found to slightly influence membrane hydrophobicity. Polyethylene glycol（PEG）,organic acids, Li Cl, Mg Cl2, and Li Cl/H2 O mixtures were proved to be effective additives to PVDF-CTFE membranes due to their pore-controlling effects and the capacity to improve the properties and performance of the resultant membranes. The occurrence of a pre-gelation process showed that when organic and inorganic micromolecules were added to PVDF-CTFE solution, the resultant membranes presented a high interconnectivity structure. The membrane prepared with dibutyl phthalate（DBP） showed a nonporous surface and symmetrical cross-section. When H2 O and Li Cl/H2 O mixtures were also used as additives, they were beneficial for solid–liquid demixing, especially when Li Cl/H2 O mixed additives were used. The membrane prepared with 5% Li Cl ＋ 2% H2 O achieved a flux of24.53 kg/（m2·hr） with 99.98% salt rejection. This study is expected to offer a reference not only for PVDF-CTFE membrane preparation but also for other polymer membranes.