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HZSM-5 zeolite modified by rare earth was prepared with ion exchange method in the study. The effects of different types of rare earth elements, modification temperatures, pH, and rare earth contents on structural stability of the as-prepared zeolite were investigated. The as-prepared zeolite was characterized by XRD, SEM and FT-IR spectroscopy. The characterization results showed that the crystal structure of the zeolite was not changed by the modification of rare earth, which was evenly distributed on the surface or in the pore channel of zeolite. Sm/HZSM-5 zeolite with the highest structural stability was obtained under the following modification conditions: 2% rare earth Sm, modification temperature of 70 °C, 2 h of ion exchange, and pH 3. [ABSTRACT FROM AUTHOR]

In the study, MgAl binary water talc (MgAl-CO3-LDHs) was firstly synthesized by a steady-state co-precipitation method and then characterized by XRD, SEM and ICP-OES methods. The effects of n(Mg2+)/n(Al3+) in mixed salt solutions, pH and roasting temperature on the properties of MgAl-CO3-LDHs were mainly explored. The optimal adsorption condition of VO3- on MgAl-CO3-LDHs was determined as synthesis temperature of 25 °C, n(Mg2+)/n(Al3+) ratio of 3:1, pH 8 ± 0.1 and roasting temperature of 517 °C. The adsorption characteristics of MgAl-CO3-LDHs on VO3- were better fitted with Langmuir's isothermal equation and quasi-secondary kinetic equation. The adsorption mechanism was close to the monolayer adsorption with a saturated adsorption capacity of 53.73 mg/g. [ABSTRACT FROM AUTHOR]

In the study, MgAl binary water talc (MgAl-CO3-LDHs) was firstly synthesized by a steady-state co-precipitation method and then characterized by XRD, SEM and ICP-OES methods. The effects of n(Mg2+)/n(Al3+) in mixed salt solutions, pH and roasting temperature on the properties of MgAl-CO3-LDHs were mainly explored. The optimal adsorption condition of VO3- on MgAl-CO3-LDHs was determined as synthesis temperature of 25 °C, n(Mg2+)/n(Al3+) ratio of 3:1, pH 8 ± 0.1 and roasting temperature of 517 °C. The adsorption characteristics of MgAl-CO3-LDHs on VO3- were better fitted with Langmuir's isothermal equation and quasi-secondary kinetic equation. The adsorption mechanism was close to the monolayer adsorption with a saturated adsorption capacity of 53.73 mg/g. [ABSTRACT FROM AUTHOR]

In this study, the loaded diatomite was prepared with Changbai Mountain diatomite as the carrier according to different Fe/Al molar ratios. The structure and adsorption of the above materials were characterized by XRD, SEM, and ICP-OES. The effects of Fe/Al molar ratio, adsorption time, initial concentration of V(V), and the initial pH value of the solution on the adsorption performance of loaded diatomite were explored. The diatomite loaded with Fe/Al compounds could significantly improve the removal efficiency of V(V), and the removal efficiency of loaded diatomite prepared according to a Fe/Al molar ratio of 1:3 was better. Reaction equilibrium time is 24 h and the pseudo second-order kinetic equation can better describe the adsorption kinetic behavior of V(V) on loaded diatomite. When the initial concentration of V(V) increased from 15.85 mg/L to 122.5 mg/L, the unit adsorption capacity and removal rate of V(V) by loaded diatomite increased continuously. The adsorption behavior of V(V) on loaded diatomaceous earth belongs to the chemical adsorption via the multi-molecular layer, which is consistent with the Freundlich isotherm adsorption model. A weak acid environment is beneficial to the adsorption behavior of V(V) on loaded diatomaceous earth and the strong alkaline environment should be avoided. [ABSTRACT FROM AUTHOR]

Nanosized magnesium hydroxide (Mg(OH)2) with sheet and flower structure were prepared via precipitation reaction between magnesium chloride and alkaline precipitant, such as ammonium hydroxide, sodium hydroxide and urea. The structure and morphology of as-prepared samples were characterized through X-ray diffraction and scanning electron microscopy. Effect of precipitants and surface modifier on morphology and size of nano-Mg(OH)2were investigated. Heat-resistance of Mg(OH)2in polymer was discussed by thermogravimetry-differential thermal analysis. Mg(OH)2nanostructure present superior morphology and heat-resistance with NH4OH-NaOH as precipitant and 3mol% acrylic acid as surface modifier. [ABSTRACT FROM PUBLISHER]

As a new zero-optic luminescent material, carbon quantum points are widely focused and sustained, and many researchers are trying to use simple and fast methods and stable, good carbon sources to be prepared with a good fluorescent properties of carbon quantum dots. In this paper, carbon quantum dots were synthesized by solvothermal method with vanillin as carbon source, and the effects of solvothermal temperature and time on the luminescence properties of carbon quantum dots were explored. Then, carbon quantum dots were characterized by X-ray diffraction analysis, transmission electron microscopy analysis, infrared spectrum analysis, fluorescence spectrum analysis. Research results showed that ethanol solvent with vanillin as a carbon source by solvothermal method could synthesize good water soluble carbon quantum dots with weak crystallization, and its size was about 10 nm. This carbon quantum dots had obvious excitation wavelength dependence and produce blue light, which had potential application value in ion fluorescence probe or cell labeling. [ABSTRACT FROM AUTHOR]

Via wet chemical method with organic assistant, ZnS:Cu/ZnS core/shell structure was prepared. X-ray diffraction measurements showed that ZnS:Cu was formed with zinc blende structure, and ZnS shell growth on the surface was indicated through a red-shift in the UV-Vis absorption spectra with increasing particle size. The emission peak at about 510 nm was observed, which should be assigned to recombination of an electron from the shallow delocalized donor levels at thet2level of Cu2+centers. As passivation layer, effect of ZnS shell on luminescence intensity and lifetime of ZnS:Cu were investigated. Comparing with uncoated ZnS:Cu, ZnS shell really enhanced the luminescence intensity and lifetime significantly, which resulted from the reduction of nonradiative recombination sites. [ABSTRACT FROM AUTHOR]

A novel material Bi1-xGdx-BTC was obtained in situ via the solvothermal method. The effects of Gd3+ substitution on the Bi-BTC structure and photocatalytic properties of Bi1-xGdx-BTC were investigated. A standard Bi-BTC structure was observed in the X-ray diffraction spectra of the Bi1-xGdx-BTC(x ≤ 0.07). However, some diffraction peaks were changed when the x is more than 0.07 due to the different ion radius. The developed Bi1-xGdx-BTC samples exhibited higher photocatalytic activity than the pure Bi-BTC material. In RhB degradation experiments, the Bi1-xGdx-BTC(x = 0.03 and x = 0.05) materials show degradation efficiency conversion of 71% within 60 min under visible light. The high photodegradation efficiency of Bi1-xGdx-BTC could be ascribed to efficient charge transfer between Bi(III) ions and Gd(III) ions. Moreover, an active species trapping experiment confirmed that photo-generated ·O2- and ·OH is the major species involved in RhB degradation. [ABSTRACT FROM AUTHOR]

Luminescent perovskite photocatalysts activated by Pr3+ were prepared by combustion. The structural phase, morphology, and chemical composition of the as-prepared photocatalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Brunauer–Emmett–Teller (BET) analysis, and ultraviolet–visible (UV–vis) diffuse reflectance spectroscopy. The photocatalytic activities of the synthesized samples were investigated on the basis of the degradation of methylene blue (MB) under UV light irradiation. CaTiO3:Pr3+ was obtained in high purity and good crystallinity with a perovskite structure. The degradation of the photocatalyst was fitted with pseudo-first-order kinetics according to the Langmuir–Hinshelwood model. Compared to CaTiO3:Pr3+, Ca1–xTiO3:Pr3+ (x = 0–0.3) multifunctional materials exhibit higher luminescence intensity and photocatalytic activity toward the degradation of MB. Ca0.8TiO3:0.1%Pr3+ exhibited the best performance. [ABSTRACT FROM AUTHOR]