Powder Diffraction Research Articles

Crystal structure and characterization of monascin from the extracts of Monascus purpureus-fermented rice.

We present a novel solid form of monascin, an azaphilonoid derivative extracted from Monascus purpureus-fermented rice. The crystal structure, C21H26O5, was characterized by single-crystal X-ray diffraction and belongs to the orthorhombic space group P212121. To gain insight into the electronic properties of the short contacts in the crystalline state of monascin, we utilized the Experimental Library of Multipolar Atom Model 2 (ELMAM2) database to transfer the electron density of monascin in its crystalline state. Hirshfeld surface analysis, fingerprint analysis, electronic properties and energetic characterization reveal that intermolecular C-H...O hydrogen bonds play a crucial role in the noncovalent bonding interactions by connecting molecules into two- and three-dimensional networks. The molecular electrostatic potential (MEP) map of the monascin molecule demonstrates that negatively charged regions located at four O atoms are favoured binding sites for more positively charged amino acid residues during molecular recognition. In addition, powder X-ray diffraction confirms that no transformation occurs during the crystallization of monascin.

Na2.64Mn1.64(MoO4)3 and Na2.62Ni1.69(MoO4)3: physicochemical investigations and electrochemical properties as 3.5 V class positive electrode material for Na-Batteries

Powders of two new mixed molybdates Na2.64Mn1.64(MoO4)3 (1) and Na2.62Ni1.69(MoO4)3 (2) have been prepared via a solid-solid reaction. They are isostructural, both crystallizing in monoclinic system (S. G.: C2/c), Z= 1, and the unit cell parameters a= 12.74109(18) Å, b= 13.69390(15) Å, c= 7.20028(8) Å, β= 112.4314(7) °, V= 1161.22(2) Å3 (1), and a= 12.6368(2) Å, b= 13.3633(2) Å, c= 7.08501(10) Å, β= 111.9248(10) °, V= 1109.91(3) Å3 (2). The structure consists of a 3D network of corners and edges sharing [MoO4] and [MO6] polyhedral, delimiting tunnels in which the Na ions partly site. The samples were investigated by powder X-ray diffraction, infrared spectroscopy, and scanning electron microscopy coupled to energy-dispersive X-ray spectroscopy (SEM-EDX). The vibrational study confirms the existence of the functional groups. Laser Raman spectroscopy showed that the tetrahedra in the two compounds are more regular, suggesting high symmetry for the compound. The as-synthesized compounds are fiber-like grains with an average length of 10–1 μm. FT-IR spectra showed the presence of all the functional groups present in the compounds. Magnetization measurements showed their paramagnetic behavior. The title compounds were characterized by cyclic voltammetry (CV), electrochemical performance and limiting factors are also applied as electrode material for Na-ion batteries at room temperature. Benefiting from these advantages, between 1.5 V and 4.6 V, (1) and (2) deliver high specific capacities of 230 and 160 mA h·g-1 after 60 cycles, and good rate performances, respectively. It can also be inferred that the prepared electrocatalyst showed for both phases excellent Hydrogen Evolution Reaction (HER) performance with an overpotential of 531 mV for Mn and 512 mV for Ni, required to afford a current density of 10 mA.cm-2.

Biological and computational exploration of a hydrogen-bonded charge transfer complex between 8-Hydroxyquinoline and Benzene-1,4-diol in different polar solvents: Synthesis and spectrophotometric analysis

The formation and characterization of a charge transfer complex (CTC) between 8-Hydroxyquinoline and Benzene-1,4-diol (Quinol) in various polar solvents. CTCs, marked by weak yet significant interactions, are pivotal in understanding electron transfer processes and molecular recognition phenomena. The choice of 8-Hydroxyquinoline (8HQ) as the donor and Quinol (Q) as the acceptor facilitates the investigation of their interaction, given their respective electron-rich and electron-poor properties. The spectroscopic analysis, including Fourier-transform infrared (FTIR) and UV-visible spectroscopy, reveals shifts in molecular vibrations and electronic transitions, indicating the formation of the CTC. Additionally, thermal analysis techniques, such as thermogravimetric analysis (TGA) and differential thermal analysis (DTA), provide insights into the thermal stability and decomposition behavior of the CTC. Powder X-ray diffraction (PXRD) analysis offers data on the crystalline structure and morphology of the complex. Furthermore, the manuscript explores the biological significance of the synthesized CTC, including its antioxidant, antibacterial, and antifungal activities. Conductivity measurements and computational studies, such as Density Functional Theory (DFT) and molecular docking, provide further insights into the electronic properties and structural characteristics of the CTC. Overall, the study contributes to advancing the understanding of CTCs and their applications, particularly in the context of novel donor-acceptor systems. The insights gained have implications in diverse fields, including materials science, biomedical engineering, and fundamental chemistry, paving the way for tailored molecular design and functional applications.

New porous organic framework Py-PDA CHOF as fluorescent chemosensor for detecting 2,4,6-trinitrophenol in environmental samples

Covalent bonds and hydrogen bonds linked porous organic frameworks (CHOFs) as a new type of porous organic framework connected by both covalent bonds and hydrogen bonds has been reported recently. Py-PDA CHOF was synthesized using 4,4′,4′’,4′’’-(pyrene-1,3,6,8-tetrayl)tetraaniline (Py) and 2,6-pyridinedicarboxaldehyde (PDA) as building blocks. It has porous crystalline framework and exceptional thermal stability. The suspension of Py-PDA CHOF in ethanol exhibits a highly selective and sensitive “on-off” fluorescence response towards 2,4,6-trinitrophenol (TNP), with exceptionally low detection limits. The powder X-ray diffraction (PXRD) confirmed the collapse of the Py-PDA CHOF after interaction with TNP and acid, and this result further indicated the presence of hydrogen bonds within the framework. The absorption competition quenching (ACQ) and photoinduced electron transfer (PET) mechanism are responsible for fluorescence quenching of Py-PDA CHOF by TNP. As a fluorescent chemosensor capable of detecting explosives, Py-PDA CHOF holds potential application for the identification and detection of TNP in water and soil samples.

Unraveling Early-Stage Dynamics of Cage-to-Covalent Organic Framework Transformation at Liquid-Liquid Interface.

Postsynthetic linker exchange (PLE) has emerged as an emerging synthetic strategy for constructing high-quality covalent organic frameworks (COFs) from preassembled entities such as linear polymers, amorphous networks, COFs, and porous organic cages by using the principles of dynamic covalent chemistry. The PLE strategy has recently been extended at the liquid-liquid interface to fabricate highly crystalline two-dimensional (2D)-COF membranes at a faster time scale (24 h). Examining the early stages of the interfacial PLE dynamics becomes essential to understanding the expedited COF growth process. In this regard, pendant drop tensiometry has been employed to probe the initial reaction dynamics of the imine cage-to-COF transformation through dynamic interfacial tension (IFT) measurements. The contrasting trends in IFT profiles between PLE-mediated (from cage) and direct COF synthesis (from parent monomers) are in qualitative agreement with the kinetics of bulk-scale interfacial polymerizations. Further, the distinct early-stage interfacial behaviors between the diverse synthetic routes have been experimentally demonstrated using tensiometry, optical microscopy, electron microscopy, and powder X-ray diffraction (PXRD) analysis. The pivotal role of in situ generated imine intermediates (ImIs) and the phenomenon of spontaneous emulsification toward accelerated interfacial COF growth process was delineated. The current study on deploying the pendant drop tensiometric technique to examine early-stage interfacial polymerization dynamics opens up a gripping avenue for mechanistic exploration in PLE-based COF synthesis. The generality of the developed methodology to study the initial COF growth kinetics was extended to a new interfacial PLE-mediated cage-to-COF transformation.

Magnetic curcumin–copper graphene oxide as facile and recyclable heterogeneous nanocatalyst for preparation of polyhydroquinolines and sulfoxides

In this research project, a versatile procedure has been designed for the preparation of supported copper@curcumin on magnetic graphene oxide nanoparticles (GO@Fe3O4@Cur–Cu). The structure of prepared nanocatalyst was characterized by several techniques including; Fourier transform infrared, powder X-ray diffraction, thermal gravimetric analysis, energy dispersive X-ray analysis, inductively coupled plasma optical emission spectroscopy, vibrating sample magnetometer, transmission electron microscopy, and scanning electron microscopy analyses. The catalytic properties of GO@Fe3O4@Cur–Cu were examined for the efficient synthesis of polyhydroquinolines as well as the preparation of sulfoxides through selective oxidation of sulfides in the presence of hydrogen peroxide.

Temperature and pressure-responsive photoluminescence in a 1D hybrid lead halide

Low-dimensional hybrid lead halides with responsive emissions have attracted considerable attention due to their potential applications in sensing. Herein, a new one-dimensional hybrid lead bromide CyPbBr3 (Cy = cytosine cation) was synthesized to explore its emission evolution in response to temperature and pressure. The compound possesses an edge-sharing 1D double-chain structure and emits warm white light across nearly the entire visible spectrum upon ultraviolet excitation. This emission arises from the self-trapped excitons and its broadband feature is attributed to the strong electron-phonon coupling as revealed by the variable-temperature photoluminescence experiments. Moreover, a 4.5-fold pressure-induced emission enhancement was observed at 2.7 GPa which is caused by the pressure suppressed non-radiative energy loss. Furthermore, in-situ powder X-ray diffraction and Raman experiments reveal the maxima of the emission enhancement is associated with a phase transition at the same pressure. Our work demonstrates that low-dimensional metal halides are a promising class of stimuli-responsive materials which could have potential use in temperature and pressure sensing.

Solubility behavior and solvation effect of a photomechanical molecular crystal trans-4-chlorocinnamic acid in twelve neat solvents at temperatures from 283.15 to 323.15 K

Solubility of trans-4-chlorocinnamic acid as a photomechanical molecular crystal material in twelve pure solvents (water, ethanol, methanol, n-propanol, isopropanol, n-butanol, isobutanol, acetonitrile, 1,4-dioxane, acetone, methyl acetate and ethyl acetate) were measured from 283.15 to 325.15 K at 101.2 kPa. The results showed that the trans-4-chlorocinnamic acid solubility increased with the temperature, the order is: 1,4-dioxane > acetone > n-butanol > ethanol > n-propanol > isopropanol > isobutanol > methanol > methyl acetate > ethyl acetate > acetonitrile > water. Powder X-ray diffraction pattern (PXRD) and differential scanning calorimetry (DSC) were used to identify and characterize the equilibrated solid phase samples. The solubility behavior and the solute–solvent interaction of trans-4-chlorocinnamic acid in each selected mono-solvent were explored by the empirical solvents polarity parameter (ET(30)), hydrogen bonding, cohesive energy density, molecular structure, and Hansen solubility parameters (HSPs). In addition, the experimental solubility data were correlated by the modified Apelblat model and Yaws model, and the fitting results of this models were all satisfactory. The intermolecular forces were determined through molecular simulations, including Hirshfeld surface (HS) and Molecular Electrostatic Potential Surface (MEPS) analysis. The results showed that hydrogen bond can be formed between trans-4-chlorocinnamic acid and the selected solvents, which can help to further explain the dissolution behavior of trans-4-chlorocinnamic acid in the solvents.

Luminescence and Dosimetry Investigations of Eu(III) Doped Ca2CeVO6 Novel Double Perovskite

A novel composition of vanadate double perovskite Ca2CeVO6 doped with Eu3+ was successfully synthesized using combustion synthesis, wherein the doping levels of Eu3+ ranged from 1 to 6 mol%. The Rietveld refinement of the powder X-ray diffraction (XRD) data confirmed the orthorhombic structure of the phosphors. Scanning electron microscopy (SEM) and energy-dispersive X-ray analysis (EDAX) were employed to investigate the surface morphology and elemental distribution in the phosphor, respectively. Under the excitation at 280 nm and 467 nm, the phosphor exhibited strong down-conversion red photoluminescence (PL) emission, attributed to Eu3+ transitions (5D0-7FJ, where J=0-3) originating from its 4f states. The intensity of PL emission shows increasing trend with increasing doping concentration. However, exceeding the threshold doping concentrations led reduction in PL intensity due to multipolar interaction effects. Additionally, the Eu3+ doped Ca2CeVO6 phosphors were subjected to irradiation with a radioactive 90Sr/90Y beta source to explore their thermoluminescence (TL) properties. Post-irradiation, the phosphors displayed prominent TL glow curves, with the most intense peak at around 94°C, followed by peaks at 160°C and 288°C. The TL intensity of these peaks exhibited a linear dose response within the dose range of 1 Gy to 50 Gy. Besides, the TL fading and reproducibility tests showed satisfactory results. Furthermore, Tmax-Tstop experiments revealed the presence of three trap centres within the trap depth range of 0.7-2.1 eV in the Ca2CeVO6:Eu3+ phosphor. Additionally, the glow curve deconvolution (GCD) was employed to determine trapping parameters, providing valuable insights into the TL behaviour of the phosphor. Overall, the results suggest that the novel phosphor under study holds promise for its applications in lighting devices and TL dosimetry (TLD).

Room-temperature hydrogen adsorption in Pd nanoparticle decorated UiO-66-NH2 via spillover

To improve room-temperature hydrogen storage, palladium (Pd) nanoparticles were innovatively decorated by carbon bridge onto the amino-group functioned Zr-terephthalate metal-organic framework (MOF) UiO-66 to reduce the diffusion energy barrier and then improve the hydrogen spillover effect. Powder X-ray diffraction shows broad Pd peak and retained UiO-66-NH2 integrity after Pd decoration. The hydrogen uptake capacity show that UiO-66-NH2-Pd exhibits best hydrogen storage performance than UiO-66-NH2 and pristine UiO-66. The hydrogen up taken in Pd decorated UiO-66 (UiO-66-NH2-1Pd) was close to 4 wt.% under 20 MPa at room temperature. Density functional theory (DFT) calculations show that hydrogen adsorption energy of UiO-66-NH2-Pd was –0.5897 eV, which was much lower than that of UiO-66-NH2 (–0.3716 eV) and UiO-66 (–0.2975 eV). Ultimately, Pd decorated NH2 group functioned UiO-66 enable improve storage capacities through hydrogen spillover under ambient conditions which could satisfy the demand for sustainable energy, especially for the long-term storage energy media.

Stabilization of lead (Pb)- and arsenic (As)-contaminated soil using pen shells (Atrina pectinata).

Pen shells (PS), a type of shellfish, are abundantly consumed, and their inedible shell residues are often discarded near the coast without consideration of reutilization. This study sought to investigate the use of natural pen shells (NPS) and calcined pen shells (CPS) to stabilize Pb and As-contaminated soil. During the investigation, NPS and CPS were applied to the contaminated soil in amounts ranging from 1 to 10 wt% and cured for 28days. After the curing process, the mineral phase was examined through X-ray powder diffraction (XRD) and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX) analysis. The XRD and SEM-EDX results revealed the presence of riversideite and ettringite, which contribute to Pb and As stabilization in the CPS-treated soil. The leachability of Pb and As in the treated soil was further examined with three types of chemical extraction methods. Extraction results using 0.1M HCl displayed a notable pH fluctuation in the extractant due to the residual amendments (NPS and CPS). The fluctuation resulted in a strong correlation of leached Pb and As with the pH of the extractant, which might hinder an accurate assessment of stabilization. In order to minimize the effect of pH, an EDTA-NH4OAc extraction was employed, suggesting its potential as a suitable assessment method. EDTA-NH4OAc extraction showed a higher effectiveness of CPS than NPS at 10 wt% of input amounts. In the SBET extraction, that uses a strongly acidic solution, a higher As leachability was observed by increasing the addition of CPS, which implied a CPS-related chemical fixation mechanism. The comparison of various extraction methods showed a higher CPS effectiveness as compared to NPS. However, it was recommended that CPS-treated soil required caution in strongly acidic conditions, especially for arsenic. This study explores the applicability of PS, which has not been investigated as an amendment for Pb and As-contaminated soil previously. Furthermore, this study revealed that utilization of various extraction methods is beneficial for gaining a comprehensive understanding of the role of CaCO3-based amendment in Pb and As-contaminated soil.

A new crystalline daidzein-piperazine salt with enhanced solubility, permeability, and bioavailability

To overcome the poor solubility, permeability, and bioavailability of the plant isoflavone daidzein (DAI), a novel salt of DAI with anhydrous piperazine (PIP) was obtained based on cocrystallization strategy. The new salt DAI-PIP was characterized by powder X-ray diffraction (PXRD), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), Fourier-transform infrared (FT-IR) spectroscopy, and optical microscopy. The results showed that the maximum apparent solubility (Smax) of DAI-PIP increased by 7.27-fold and 1000-fold compared to DAI in pH 6.8 buffer and water, respectively. The peak apparent permeability coefficient (Papp) of DAI-PIP in the Caco-2 cell model was 30.57 ± 1.08 × 10−6 cm/s, which was 34.08% higher than that of DAI. Additionally, compared to DAI, the maximum plasma concentration (Cmax) value of DAI-PIP in beagle dogs was approximately 4.3 times higher, and the area under the concentration-time curve (AUC0-24) was approximately 2.4 times higher. This study provides a new strategy to enhance the dissolution performance and bioavailability of flavonoid drugs, laying a foundation for expanding their clinical applications.

Pyridazine-Promoted Construction of Vinylene-Linked Covalent Organic Frameworks with Exceptional Capability of Stepwise Water Harvesting.

In this study, we successfully developed two novel vinylene-linked covalent organic frameworks (COFs) using 2-connected 3,6-dimethylpyridazine through Knoevenagel condensation. These COFs featured finely tailored micro-/nano-scale pore sizes, high surface areas and stable non-polar vinylene linkages. Finely resolved powder X-ray diffraction patterns demonstrated highly crystalline structures with a hexagonal lattice in the AA layer stacking. The resulting one-dimensional channels possess strong hydrogen-bond accepting sites arising from the decorated cis-azo/azine units with two pairs of fully exposed lone pair electrons, endowing the as-prepared COFs with exceptional water absorption properties. The g-DZPH-COF exhibited successive steep water uptake steps starting from low relative pressures (P/PSTA=0.1), with the remarkable water uptake capacity of 0.26 g/g at P/PSTA=0.2 (25 °C), which is the optimal value recorded among the reported COFs. Dynamic vapour sorption measurements revealed the fast kinetics of these COFs, even in the cluster formation process. Water uptake and release cycling tests demonstrated their outstanding hydrolytic stability, durability, and adsorption-desorption retention ability.

Photocatalytic Performance of ZnO@ZnS Core–Shell Heterostructures for Malachite Green and Rhodamine B Dye Degradation

The one‐step green synthesis of wide band gap zinc oxide@zinc sulfide (ZnO@ZnS) core–shell nanostructures offers promising prospects in wastewater treatment. These nanostructures exhibit a porous nature crucial for effective dye adsorption, as evidenced by Brunauer‐Emmett‐Teller (BET) and microscopic characterization. The synthesized material demonstrates high stability and minimal agglomeration, verified through BET analysis and zeta potential measurements. X‐ray powder diffraction confirms the presence of ZnO and ZnS phases. Transmission electron microscopy reveals the development of porous nanorods on the core surface, maximizing the surface area for dye adsorption. In wastewater treatment, the nanostructures exhibit notable performance, degrading 90% of malachite green and 50% of rhodamine B dyes within 120 min under normal conditions. Detailed discussions delve into the degradation mechanism, elucidating the major species responsible for the process. This study underscores the potential of ZnO@ZnS nanostructures in efficient organic pollutant removal, marking a significant advancement in environmental remediation.

Study of the preparation, characterization, and solubility of lidocaine complexed with 5-sulfosalicylic acid dihydrate

Objective: This study was to prepare solid dispersions of lidocaine (Lid) with 5-sulfosalicylic acid dihydrate (SSA) by freeze-drying (freeze-dried [FD] Lid/SSA = 1/1) and to evaluate their physical properties. Methods: Here, we evaluated the physicochemical properties and solubility of solid dispersions of lidocaine (Lid) and 5-sulfosalicylic acid dihydrate (SSA) prepared by freeze-drying (freeze-dried [FD] Lid/SSA = 1/1). Results: Differential scanning calorimetry measurements showed that after freeze-drying, the endothermic peak due to Lid melting, the dehydration peak, and the endothermic peak due to SSA melting disappeared. Powder X-ray diffraction results showed that the characteristic Lid and SSA peaks disappeared after freeze-drying, indicating a halo pattern. The near-infrared spectroscopy results suggested that Lid-derived -NH and -CH groups and the Lid-derived -OH and -CH groups from the SSA peak shifted and broadened after freeze-drying, suggesting their involvement in complex formation through Lid/SSA intermolecular interactions. Nuclear Overhauser effect spectroscopy-nuclear magnetic resonance (NMR) measurements showed a cross-peak due to the interaction between the Lid-derived -CH group and the SSA-derived -OH group, suggesting hydrogen bonding. Diffusion-ordered spectroscopy NMR measurements showed that the diffusion coefficients of Lid and SSA aggregated in FD Lid/SSA, suggesting a change in Lid dispersibility in the solvent owing to the formation of a complex with SSA. The solubility of FD Lid/SSA was approximately 88 mg/mL (∼20-fold higher than that of Lid). Conclusions: These findings suggest that complex formation occurred in FD Lid/SSA; this enhanced the solubility of this dispersion.

Application of polyethylene glycol 8000 as plasticizer for the development of ellagic acid and Eudragit® EPO based solid dispersions using hot melt extrusion.

Solid dispersion formation by Hot melt extrusion (HME) is a widely used formulation strategy to improve the solubility and bioavailability of poorly water-soluble drugs. Despite this, they are limited by various factors such as drug-excipient miscibility, poor stability, limited drug loading and extrudability of physical drug-excipient mixtures. In this work, polyethylene glycol 8000 (PEG 8000) was used as a plasticizer for the manufacture of ellagic acid solid dispersions (EASD) with high drug loading. Indeed, EA is a polyphenolic active compound with antimalarial and other promising therapeutic activities. However, its low solubility and low permeability limit its therapeutic use. Solid dispersions formation may overcome this challenge, but its high melting point negatively influences the extrudability of its binary physical mixtures with a high drug loading rate, hence the need to use a plasticizer. Thus, five formulations consisting of EA, Eudragit® EPO and PEG 8000 in the ratio of 15:75:10 (F1), 20:70:10 (F2), 25:65:10 (F3), 15:80:5 (F4) and 20:85:5 (F5) % w/w, respectively, have been extruded, four of which were successful. The extrudates were evaluated by X-ray powder diffraction, FTIR spectroscopy and in vitro dissolution tests. Based on the results of these tests, the F5 formulation was identified as the most promising. Indeed, after 15 min of dissolution test, the dissolution rate of ellagic acid from the formulations was 62.67±3.10%, 58.74±7.23 %, 88.75±3.02% and 83.47±4.40% respectively for formulation F1, F2, F4 and F5. Moreover, the results of the FTIR spectroscopy analyses showed stronger interactions between the different constituents in the F4 and 5 formulations compared to the F1 and 2 formulations. Extruded materials of the F5 formulation, characterized by solid state nuclear magnetic resonance (ssNMR) spectroscopy and subjected to stability studies, showed good physical stability for twelve months under real-time stability study conditions and for six months under accelerated conditions.

Florfenicol core–shell composite nanogels as oral administration for efficient treatment of bacterial enteritis

To reduce the bitterness of florfenicol, avoid its degradation by gastric acid, and enhance its antibacterial activity against Escherichia coli by targeting and slowly releasing drugs at the site of intestinal infection, with pectin as an anion carrier and chitosan oligosaccharides (COS) as a cationic carrier, florfenicol-loaded COS@pectin core nanogels were self-assembled by electrostatic interaction and then encapsulated in sodium carboxymethylcellulose (CMCNa) shell nanogels through the complexation of CMCNa and Ca2+ to prepare florfenicol core–shell composite nanogels in this study. The florfenicol core–shell composite nanogels were investigated for their formula choice, physicochemical characterization, pH-responsive performances, antibacterial activity, therapeutic efficacy, and in vitro and in vivo biosafety studies. The results indicated that the optimized formula was 0.6 g florfenicol, 0.79 g CMCNa, 0.30 g CaCl2, 0.05 g COS, and 0.10 g pectin, respectively. In addition, the mean particle diameter, polydispersity index, zeta potential, loading capacity, and encapsulation efficiency were 124.0 ± 7.2 nm, –22.9 ± 2.5 mV, 0.42 ± 0.03, 43.4 %±3.1 %, and 80.5 %±3.4 %, respectively. The appearance, lyophilized mass, resolvability, scanning electron microscopy (SEM), transmission electron microscopy (TEM), powder X-ray diffraction (PXRD), and fourier transform infrared (FTIR) showed that the florfenicol core–shell composite nanogels were successfully prepared. Florfenicol core–shell composite nanogels had satisfactory stability, rheology, and pH-responsiveness, which were conducive to avoid degradation by gastric acid and achieve targeted and slow release at intestinal infection sites. More importantly, florfenicol core–shell composite nanogels had excellent antibacterial activity against Escherichia coli, a satisfactory therapeutic effect, and good palatability. In vitro and in vivo biosafety studies suggested the great promise of florfenicol core–shell composite nanogels. Therefore, the prepared florfenicol core–shell composite nanogels may be helpful for the treatment of bacterial enteritis as a biocompatible oral administration.

Intermediate valence behavior of the ternary cerium-nickel-phosphide Ce2Ni12P5

The crystal structure of the ternary phosphide Ce2Ni12P5 (La2Ni12P5-type structure) has been determined from X-ray powder diffraction data: full profile refinement, monoclinic symmetry, space group P21/m, a = 10.7809(2) Å, b = 3.6869(1) Å, c = 13.1490(3) Å, β = 107.776(4)º, RI = 0.068, RP = 0.044, RwP = 0.060. Ce2Ni12P5 is a ferromagnet with a Curie temperature of 5.8(5) K. A significant deviation from the linearity of the temperature dependence of the electrical resistance for Ce2Ni12P5 has been found. The low-temperature part of the electrical resistance indicates the presence of magnetic interactions in Ce2Ni12P5. The influence of a magnetic field on the electrical resistance of Ce2Ni12P5 has been studied. The X-ray absorption spectrum at the Ce LIII edge and X-ray emission spectra of Ni and P at the K and LIII edges have been studied experimentally and theoretically using DFT+U calculations. The calculations show good agreement with the experimental measurements. The effective valence of Ce in Ce2Ni12P5 determined based on the Ce LIII absorption spectrum is ϑeff ∼ 3.05.

Recycling of additively printed anisotropic Nd-Fe-B bonded magnets

A high potential cost-effective and environmentally friendly method has been applied for recycling anisotropic Nd-Fe-B bonded magnets. Waste additively printed Hydrogenation-Disproportionation-Desorption-Recombination (HDDR) Nd-Fe-B anisotropic bonded magnet was pulverized into composite powder containing Nd-Fe-B particles and nylon binder through cryomilling at a liquid nitrogen temperature (∼77 K) under Ar inert atmosphere. Then, the cryomilled composite powder was warm compacted into a bonded magnet. The magnetic particles were aligned during post-compaction annealing under a magnetic field of 30 kOe. The recycled bonded magnets have a higher density (3 % enhancement), but slightly inferior magnetic properties compared to the original magnets, i.e., the magnetic remanence, coercivity and maximum energy product are reduced by 2 %, 3 % and 8 %, respectively. The scanning electron microscopy revealed that some HDDR Nd-Fe-B powder crumbled into fine particles during cryomilling. Powder X-ray diffraction showed a small amount of Nd-oxide impurity in the cryomilled powder. The slightly deteriorated magnetic properties are ascribed to the oxidation of Nd-Fe-B particles due to formation of fresh fracture surface during cryomilling. The approach enables the direct reuse of end-of-life bonded magnets in an economical and environmentally friendly way.

High-temperature heat treatment of hydrogen-reduced bauxite residue-calcite pellets for iron particles growth and separationTraitement thermique à haute température de boulettes de résidus de bauxite et calcite réduites à l’hydrogène pour la croissance et la séparation des particules de fer

ABSTRACT Bauxite residue characterised as a polymetallic source containing iron, alumina, titanium, calcium, silicon and rare earth elements offers an opportunity for reduced waste volume and the recovery of valuable metals. This study focuses on the agglomeration of bauxite residue with calcite, followed by hydrogen reduction at 1000°C. The resulting iron particles in the reduced pellets were initially very small distributed in a porous oxide matrix, posing challenges for physical separation methods. To address this issue, further heat treatments were conducted on the reduced pellets in an argon atmosphere, ranging from 1100°C to 1550°C. Phase analysis and microstructural examinations were performed using X-ray powder diffraction and scanning electron microscopy, respectively. Experimental findings indicate that the size of iron particles in the reduced pellets increases with higher heat treatment temperatures. Up to 1200°C, the oxide matrix remains a solid state, transitioning to a semi-molten and molten state above this heat treatment temperature and complete separation of iron from the oxide matrix above 1500°C. An alkali-leachable phase is present in the reduced pellets, initially in the form of calcium aluminate (mayenite), while above 1400°C, this phase dissociates to form monocalcium aluminate, and complete conversion at 1500°C. As observed in the microstructural analysis, there is an increase in the particle size of iron in both the solid and semi-molten states with an increasing in temperature from 1100°C up to 1300°C. This comprehensive study sheds light on the transformative effects of varying heat treatment temperatures on the composition and microstructure of bauxite residue-based materials.