Ca2SiO4 is a phase-change material, and γ- and β-Ca2SiO4 usually coexist in the sintered product. The overlap of the diffraction data between the two polymorphs makes the relevant phase identification difficult. In this work, the Eu3+ rear-earth fluorescence probe is introduced in the preparation of Ca2SiO4, and the obtained result indicates that the introduction of Eu3+ ions facilitates the increase in the content of β-Ca2SiO4 in the final product. In addition, the differences of the local coordination environments between the two Ca2SiO4 phases obviously influence the crystal-field splittings of Eu3+ ions, especially in the 5D0 → 7F0 nondegenerate and 5D0 → 7F1 magnetic dipole transition regions. On the basis of the excitation from the Eu3+–O2– charge-transfer band, the low-temperature spectral changes are systematically discussed. The transition area ratios of 5D0 → 7F0/5D0 → 7F2 and 5D0 → 7F1/5D0 → 7F2 present a positive and negative correlation with the increase of the excitation wavelength, respectively. The four nonequivalent 5D0 → 7F0 emission peaks with low to high wavelengths are identified as Eu3+ ion-occupied Ca(β-2) (571.8 nm), Ca(β-1) (573.8 nm), Ca(γ-2) (577.6 nm), and Ca(γ-1) (578.9 nm) sites. Besides, the relationship between the phase content of γ-Ca2SiO4 and the spectral change for the 5D0 → 7F0 emissions of the Eu3+ ions is also built. It is fitted by an exponential correlation function and is quite suitable for the prediction of the phase content of γ-Ca2SiO4 based on the measured spectra. The findings in this study manifest the promising application of the Eu3+ fluorescent probe in phase identification and enrich the analysis method in inorganic phase-change materials.
Yanan Yuan,Chunliu Yang,Tianwei Lv,Fengxia Qiao,Yang Zhou,Hongyuan Yan
The synthesis of biomacromolecule imprinted materials is a challenge with the bulkiness and instability of macromolecule , such as protein. A green strategy to prepare hydrophilic protein-imprinted resin (HPIR) was firstly developed using resorcinol and melamine as double functional monomers , hexamethylenetetramine instead of formaldehyde as crosslinker, water as solvent, and bovine serum albumin (BSA) as a dual-function template. BSA as dual-function template could not only act as template but also porogen in the preparation of HPIR. According to the adsorption experiments, the adsorption kinetics of BSA on HPIR obeyed pseudo-second-order adsorption kinetics and the equilibrium data were best described by Langmuir isotherm model. The adsorption capability was 44.3459 mg g −1 (25 °C), and the imprinted factor for binding BSA is 5.78. HPIR showed high adsorption capacity, fast mass transfer rate, and specific selectivity towards BSA in aqueous solvent . More importantly, HPIR can be applied to selectively adsorb target protein BSA in urine without the matrix interference of biological matrix, therefore, it is promising for HPIR to be applied to proteomics , diagnostics, and pharmaceutics.
Shaoping Ma,Fenfang Li,Liangliang Liu,Liping Liao,Li Chang,Zhijian Tan
Two-phase system was widely used for the enantioselective liquid-liquid extraction (ELLE) of various enantiomers . The organic solvents are generally used as the extractants, moreover, the additional chiral selectors should be added to the extraction system. In this study, a biphasic recognition chiral extraction (BRCE) system based on hydrophilic and hydrophobic DESs was developed for the ELLE of tryptophan enantiomers. DESs can be simultaneously used as the phase-forming components and chiral selectors. The hydrophobic/hydrophilic methyl trioctyl ammonium chloride- L(+)-Diethyl L-tartrate/HP-β-CD-L-(−)-Malic Acid (MTAC-DE/HC-MA) system was screened as the optimal extraction system. The molar ratios of hydrogen-bond acceptor (HBA) and hydrogen-bond donor (HBD) in DESs were optimized for the enantioseparation. The other factors of phase volume ratio, initial tryptophan concentration, pH value, and extraction temperature were studied. The maximum enantiomeric excess ( e.e. ) value of 38.46% was obtained under the optimal conditions by one-step extraction. This BRCE system used for the chiral separation of tryptophan enantiomers has the advantages of environmental friendliness , simple operation, and high efficiency, which has the practical application potentiality in the continuous enantioseparation process.
危险品化学品经营许可证（带存储）