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ZIF-8, a metal–organic framework that has significant benefits such as a substantial specific surface area, abundant active sites, and high porosity, has extensive application in environmental remediation. However, ZIF-8 is powdery and easily agglomerated, making it difficult to separate ZIF-8 from aqueous solutions and thus limiting its practical application in wastewater treatment. In this work, sodium alginate was chosen as a gel matrix, and CaCl2 as a cross-linking agent to form a calcium cross-linked MOF gel material (ZIF-8/SA). The batch adsorption investigations demonstrated that the saturated adsorption capacities of ZIF-8/SA in single Mn2+ pollution solution and Mn–Cu–Cd composite pollution solution are 179.86 mg g−1 and 101.86 mg g−1, respectively. Specifically, the adsorption of Mn2+ followed the Langmuir model and exhibited monomolecular layer adsorption. Furthermore, the adsorption of Cu2+ and Cd2+ followed the quasi-first-order kinetic model, which is primarily physical adsorption. The adsorption order of ZIF-8/SA for contaminants in the adsorption process is as follows: Cu2+ > Cd2+ > Mn2+. The SEM-EDS, FT-IR, and XPS studies revealed that the adsorption mechanism of ZIF-8/SA mostly involves ion exchange, coordination of carboxyl/hydroxyl/amino groups, and electrostatic attraction. To summarize, the experimental findings of this study demonstrate that the synthetic ZIF-8/SA hydrogel has promising applications for practical pollution treatment. [ABSTRACT FROM AUTHOR]

High mineralization activity is a crucial requirement in bone tissue engineering. In this study, a novel calcium citrate compounded amorphous calcium phosphate (CAP)/polyurethanes (PUs) composite porous 3D scaffold was developed by in situ polymerization via gas foaming method. The physical and chemical properties were characterized and discussed. The results showed that the HDI can react mildly with hydroxyl (–OH) groups of PEG, while gas foaming action was caused by the release of CO2 occurred in the reactive process, resulting in a uniform porous structure of PUs scaffold. The porosities of the synthetic PEGCAP porous scaffolds are all above 70% with high interconnectivity, while the porosity decreased 27% with increasing CAP to 40%. Furthermore, the mechanical properties of porous scaffolds enhanced about 16 times after addition of CAP. After immersing in simulated body fluid (SBF), the surface structure of the porous scaffold kept stable, and surface deposits formed, indicating that the porous scaffold has good mineralization activity. In addition, the in vitro cells proliferation assay confirms the excellent bioactivity of PEGCAP porous scaffolds. [ABSTRACT FROM AUTHOR]

Na-ion batteries (SIBs) are emerging as a promising alternative to Li-ion batteries for large-scale energy storage in light of abundant Na resources and their low cost. Development of appropriate electrode materials that can conquer some critical issues such as low theoretical storage capacity and sluggish redox kinetics resulting from the larger radius of Na is urgently needed for their practical applications. In this work, boron-rich 2D BxN (x = 2, 3, and 5) has been explored as promising anode materials for high-performance SIBs based on density functional theory calculations. BxN electrodes exhibit moderate affinity toward Na-ions with adsorption energies of −0.41 to −1.21 eV, which allows stable Na-ion intercalation without the formation of metal dendrites. Moreover, both B3N and B5N deliver low diffusion barriers (0.28 and 0.08 eV) for Na-ion migration, guaranteeing a high charging/discharging rate. More importantly, these BxN anodes exhibit not only a remarkably high theoretical capacity of 1129–1313 mA h g−1 but also a low open-circuit voltage (0.45–0.87 V), which is important to achieve high energy density. AIMD simulations have confirmed the excellent cyclability of BxN electrodes during reversible lithiation/delithiation. These results suggested that the BxN electrode could be used as a new lightweight SIB anode with high capacity, cyclability, and desired rate performance. [ABSTRACT FROM AUTHOR]

The preparation of a porous shape memory hydrogel with excellent shape changing performance is a hot research topic at present. In this paper, hydrophilic hydrogels were synthesized using polypropylene glycol (PPG) and polyethylene glycol (PEG) as raw materials and hexamethylene diisocyanate (HDI) as crosslinking agent. The pore structures were developed by gas foaming and salt leaching methods. The results showed that the hydrophilicity of hydrogel and the swelling rate in phosphate buffered saline (PBS) increased with the increase of PEG mass fraction, the shape changing performance of hydrogels varied as well with high shape recovery rate ≥90%. The recovery speed in aqueous environment was faster than in the air. After embedding hydroxyapatite (HA) particles, the materials exhibited appropriate degradable properties and good in vitro mineralization performance. Therefore, the obtained PPG/PEG system hydrogels is expected to become an ideal platform for tissue engineering and other applications in the biomedical field. [ABSTRACT FROM AUTHOR]

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]

As an important industrial catalytic material, ZSM-5 zeolites are still facing durability issues. The long-time exposure among high temperature steam during the catalytic reaction becomes the main drawback for ZSM-5 zeolite application in industry. In this study, we investigate the effects of rare-earth-ions (La, Ce, Nd, Sm, Gd, and Dy) doping on the catalytic activity and hydrothermal stability of ZSM-5 zeolites based on density functional theory. The results demonstrate that the introduced rare-earth-ions prefer to adsorb on the top of Al atom (T12 site). The Milliken charge transfer and electron density difference confirm the strong electrostatic interactions between the ZSM-5 zeolites and rare-earth-ions. The activation reaction of butene is investigated to estimate the catalytic activity of rare-earth-ion doped ZSM-5. The results demonstrate that La and Sm doped ZSM-5 zeolites exhibit superior performance on butene activation. In addition, rare-earth-ions decoration show enhanced sodium tolerance performance with decreased affinity toward Na during the catalytic process. This study demonstrated that the modification of rare-earth-ions can effectively improve the hydrothermal stability and catalytic activity of ZSM-5 zeolites. [ABSTRACT FROM AUTHOR]

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]

Traditional shape memory polymers (SMPs) could avoid large volume trauma during implantation; however, for bone repair, scaffolds with high porosity and biomineralization are essential to promote bone regeneration. A novel porous composite scaffold with high biomineralization activity was developed by sequential gas foaming and a freeze–drying method. The results showed that the cross-linked block structure of the polymer matrix presented excellent shape memory properties, and osteogenesis was promoted by citrate functionalized amorphous calcium phosphate (CCACP). CCACP improved the mechanical strength of the scaffold, and the synergistic effect of CCACP and PEG promotes hydrophilicity and further promoted cell adhesion. Bending experiments indicated that the shape-memory effect of the scaffolds could be varied by varying the CCACP content. In addition, hydroxyapatite deposition was sped up as CCACP accelerated the mineralization of the scaffolds. Moreover, the result of the CCK-8 assessment suggested that composite scaffolds exhibited high biocompatibility, and the cells extended out abundant filopodia to adhere onto the scaffolds. In rat bone defect models, the obtained scaffolds promoted new bone formation compared to the control group. The developed composite scaffolds show potential for minimally invasive bone repair application. [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, porous composite materials were prepared from calcium citrate (CC) and polylactic acid (PLA). Scanning electron microscopy (SEM) showed that the prepared composite materials had the uniformly pore distribution and suitable pore size for bone tissue engineering and displayed proper mechanical properties. As confirmed in X-ray diffraction (XRD), SEM and thermal analysis, the lipophilic property of CC had the improved compatibility and uniform dispersion in the PLA matrix. In addition, the prepared materials showed the high mineralization activity and the ability to guide the formation of apatite since the hydrophilicity of CC improved the wettability of the composite materials. In vivo animal experiments showed that the material was nontoxic and had good biocompatibility. Furthermore, the synergic degradation of CC and PLA effectively neutralized the acidic environment, thus preventing partial inflammation caused by acidic products. CC/PLA composite materials provide a promising new bone repair material for bone tissue engineering. [ABSTRACT FROM AUTHOR]

Self‐activated Ca5Mg3Zn(VO4)6 and Ca5Mg3Zn(VO4)6:xEu3+ phosphors were synthesized via a high‐temperature solid‐state reaction route. The crystalline structure and luminescence properties of the phosphors were analyzed using an X‐ray diffractometer and a photoluminescence spectrometer. The explored results indicated that by varying calcination temperature and the raw material ratio of Ca2+/Mg2+/Zn2+, the phosphors could be developed with different phases, crystallinity, and various fluorescence performances. The fluorescence spectrum of Ca5Mg3Zn(VO4)6 showed a broad emission band over the range 400–650 nm under an excitation wavelength of 330 nm, as well as green light emission. Furthermore, after introduction of Eu3+ ions in Eu(VO4)4, the luminescence intensity of the Eu3+ ions greatly increased as the Eu3+ ion concentration increased at the 393 nm excitation wavelength, showing green–yellow light emission simultaneously. Therefore, the obtained phosphors could be used as a potential green–yellow‐emitting luminescent material in a white light‐emitting diode device. [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]

In this study, a novel hydroxyapatite (HA)/polyurethane (PU) composite porous 3D scaffold was developed by in situ polymerization. Aliphatic hexamethylene diisocyanate (HDI) as a nontoxic and safe agent was adopted to produce the rigid segment in PU polymerization. HA powder was compounded in a PU polymer matrix during the polymeric process. The macrostructure and morphology as well as mechanical strength of the scaffolds were characterized by FTIR, XRD and SEM. The results show that the HDI can react mildly with hydroxyl (–OH) groups of polytetramethylene ether glycol and a mild foaming action caused by the release of CO2 gas occurred simultaneously in the reactive process, thus producing a uniform porous structure of HA/PU scaffold. The HA/PU composite scaffold with a high HA content of about 30 wt% has a porosity of more than 60% and a pore size from 100 to 800 μm. After immersed in simulated body fluid, the scaffolds were investigated by weight loss experiments and FTIR. The results show that polymerized component of HA/PU scaffolds degraded gradually in vitro, while HA component presented a classic trend of dissolution then deposition procedure. Three hydrolysis processes may happen in the PU degradation. The HA/PU scaffolds should be a promising material for bone tissue regeneration in clinic. [ABSTRACT FROM AUTHOR]