Zirconium Source Research Articles

Preparation of ZTA composite ceramics derived from sol–gel method by DIW printing

AbstractIn this study, the dense and fine‐grained zirconia toughened alumina (ZTA) composite ceramics were efficiently prepared by 3D gel printing technology. Zirconia powder, zirconium oxychloride, and zirconium sol were introduced into boehmite gel as zirconium sources, and their effects on rheological properties, drying characteristics, microstructure, and mechanical properties of ceramics were discussed. The results showed that all gels exhibit reversible shear thinning properties. The gel with zirconia powder has a relaxation phenomenon; zirconium sol forms another gel network in the boehmite gel network, and two linear viscoelastic regions are observed. The gel with zirconia powder has the highest solid loading, small drying shrinkage, and fewer drying defects. The grain growth of ZTA ceramics with zirconium sol was inhibited, and the zirconia grains were evenly distributed, with the highest bending strength of 518 ± 103 MPa. The new gel preparation method and gel drying process offer great possibilities for manufacturing optical glasses and functional ceramics with high‐performance geometric structures, which cannot be achieved by traditional manufacturing methods.

Anisotropic ZrO2 porous ceramic constructed using bacterial cellulose nanofiber framework for extreme insulation environment

Zirconium oxide (ZrO2) porous ceramic shows promising application in construction and industry due to its remarkable chemical stability, corrosion resistance, oxidation resistance, and thermal resistance. While the construction of stable anisotropic ZrO2 porous ceramic is still a challenge. In this study, we report an anisotropic ZrO2 porous ceramic using bacterial cellulose nanofiber (BCNF) as a framework and zirconium oxychloride octahydrate as the zirconium source. ZrO2 porous ceramic was achieved through directional freezing, vacuum freeze-drying, and calcination processes. ZrO2 arrangement relies on the BCNF framework and retains the three-dimensional (3D) structure after the calcination of BCNF. Results reveal that the resulting ZrO2 porous ceramic possesses a well-ordered anisotropic network structure, exhibiting excellent stability at 1100 °C in air. Benefiting from the anisotropic structure, ZrO2 porous ceramic exhibits high load-bearing capacity in the longitudinal direction, and thermal insulation with a significant temperature difference of approximately 50 °C between transverse and longitudinal heat transfer. It also keeps stable in extreme conditions including low temperature and acid solution. These unique properties make it an ideal insulation material in extreme environments where the protection of structures with complex shapes and variable dimensions is critical.

Controlled synthesis of defective MOF-808 and its application in levulinic acid esterification

Defective MOF-808 (Def. MOF-808) plays a pivotal role in catalysis, offering the potential for optimizing catalytic reactions and enhancing reactivity. Through precise control of MOF-808 synthesis conditions, including time, temperature, zirconium (Zr) source, ligand ratio, defect agent type, and content, we systematically studied their effect on material properties. The results showed that by adjusting these conditions, we synthesized a series of MOF-808 materials with varying defect concentrations, referred to as Def. MOF-808. Shorter synthesis times, lower temperatures, defect agents with stronger coordination capabilities, and increased defect agent concentration or reduced organic ligand concentration effectively enhance Def. MOF-808’s defect concentration. The presence of defect sites facilitates the effective binding of the sulfate group, thereby amplifying the level of sulfation and augmenting its acid catalytic potential. Furthermore, this study unveiled a direct link between defect concentration and the catalytic activity observed in the levulinic acid esterification reaction. The Defect-engineered MOF-808 optimized through response surface design demonstrates exceptional heterogeneous acid catalysis performance, achieving impressive conversion rates of 97.5% and selectivity of 96.2%, coupled with remarkable catalytic stability. This study highlights defect engineering as a successful strategy to improve MOF-808 catalyst performance, offering insights for future enhancements.

Preparation of ZrP2O7-based fiber composites by in situ synthesis method

ZrP2O7-based fiber composites were prepared by in situ synthesis and their microstructure, thermal conductivity, mechanical and dielectric properties were determined. The chemical reaction with BPO4 as the phosphorus source and nano-ZrO2 as the zirconium source was initiated at 900°C, which promotes liquid-phase sintering and reduces the sintering densification temperature of the ZrP2O7-based fiber composites by generating small ZrP2O7 grains and low-melting B2O3. The lower sintering densification temperature and the appropriate amount of network formers effectively suppressed the high-temperature crystallization phenomenon of the high-silica-oxygen fibers, strengthened the interfacial bonding between the fibers and the matrix, and improved the interfacial debonding problem of the ZrP2O7-based fiber composites. It is found that the ZrP2O7-based fiber composites possess low dielectric constant, low dielectric loss, good thermal conductivity, and acceptable mechanical properties, which can meet the relevant application requirements of centimeter-wave technology.

Deep eutectic system based C3N4-Zr composite material for highly efficient removal of fluoride in hydrochloric acid

The fluorine chemical industry's rapid growth demands efficient strategies for treating and utilizing the costly and inefficient byproduct, fluoride-containing hydrochloric acid, posing a significant challenge. In this study, a cost-effective method was developed for preparing an acid-resistant and efficient defluorination material. Carbon nitride (C3N4) was chosen for its exceptional acid resistance and was modified via template-free doping with different zirconium source. Characterization results through XRD, FTIR, BET, XPS, SEM, and TEM confirm the successful synthesis of CN-Zr using zirconium chloride (ZrCl4) with a specific surface area of 87.77 m2/g. Furthermore, the adsorption results indicate outstanding fluoride adsorption performance of CN-Zr in hydrochloric acid, with a maximum adsorption capacity of 145.34 mg/g and minimal zirconium leaching. Moreover, the adsorption mechanism was systematically studied using Zeta potential, FTIR and XPS characterization. The findings indicate that Zr was integrated with C3N4 uniformly by forming a deep eutectic system (DES), utilizing exposed terminal amino groups for effective hydrogen bonding with HF which predominates as the primary fluorine existence in hydrochloric acid. Meanwhile, the enhanced ion exchange, complexation of Zr-F and strong electrostatic attraction all contribute to improving adsorption. Finally, the assessment of recyclability performance and operation cost demonstrate that the material can maintain 80 % of its initial adsorption capacity after five cycles. The cost analysis results indicate that the adsorption cost is only 0.3157 CNY/g, making it considerable competitive in the industry.

Insight into Structural and Physicochemical Properties of ZrO2-SiO2 Monolithic Catalysts with Hierarchical Pore Structure: Effect of Zirconium Precursor

Zirconia–silica monolithic catalysts with hierarchical micro/macroporous structure were obtained in a sol-gel process combined with phase separation using inorganic salts, i.e., oxychloride, oxynitrate and sulphate, as a zirconium source. It was found that the use of zirconium oxychloride and prehydrolysis of tetraethoxysilane (TEOS) resulted in materials characterized by a well-developed continuous structure of macropores with a diameter of ca. 10 μm. For zirconium oxynitrate and sulfate modified materials, the prehydrolysis hardly affected the macropore size. The micropores with a diameter of 1.5 nm in the skeleton of all materials provided a large surface area of 550–590 m2/g. A high dispersion of zirconia in the silica skeleton in all studied materials was shown. However, the largest surface concentration of Lewis and Brönsted acid sites was found in the monolith synthesized with zirconium oxychloride. The monoliths were used as a core for continuous-flow microreactors and high catalytic activity was confirmed in the deacetalization of benzylaldehyde dimethyl acetal. The process was characterized by a high efficiency at low temperature, i.e., 35 °C.

High performance MOF UiO-66 membranes for MeOH/MTBE separation

The preparation of high-performance polycrystalline MOF membranes for MeOH/MTBE separation poses a challenge. In this study, intact 400 nm thick UiO-66 membranes with well-controlled structures were successfully fabricated using a novel formulation. The high ligand/metal ratios and the new zirconium sources provide ideas for designing UiO-66 membranes with effective pore structures. Consequently, the membranes exhibited an exceptional pervaporation performance, achieving a flux of 5.68 kg m−2 h−1 and a separation factor of 28000 for MeOH/MTBE (5/95 wt/wt.%) at 40 °C. Further, the UiO-66 membranes have excellent temperature and concentration resistance and remain stable during 120 h of operation. The high pervaporation performance, along with this stability, demonstrates that this UiO-66 membrane is a competitive candidate for MeOH/MTBE separation.

Effect of Mg stoichiometry on self-propagating high temperature synthesis (SHS) of ZrC nanoparticles in ZrO2-Mg-C system

ABSTRACT It is significant to develop the production processes of Zirconium Carbide (ZrC) nanoparticles due to its superior properties. In this study, self-propagating high-temperature synthesis (SHS) followed by an acid leaching route was used to produce ZrC powder. ZrO2 was used as the zirconium source, C black as the carbon source and Mg as reductant. After modelling thermodynamically with the FactSage 7.1 software in terms of adiabatic temperature and possible phases, SHS processes were carried out with varying reductant stoichiometry (90%, 100%, 110%, 120%) and applying chemical treatment with HCl leaching for purification. The obtained products were characterised by XRD and SEM-EDS analysis. The optimum reductant stoichiometry for the production of ZrC was determined as 110%. As a result of the leaching processes, it was revealed that ZrC powders with an average particle size of 320 nm and containing a small amount of oxide residues could be synthesised. Compared to carbothermal reduction, which is the main production method of the material, the desired compounds were synthesised with much lower energy consumption and in much finer particles.

Synthesis and assessment of properties of ZrB2 nanopowder utilizing boro/carbothermal reduction method

AbstractThe reason of this study is to synthesize ZrB2 nano powder utilizing boric acid and phenolic resin. Within the study of zirconia as a source of zirconium, boric acid was used as a source of boron and phenolic resin as a carbon source. The theoretical and experimental studies of ZrB2 were synthesized by boro/carbothermal diminishment from the novel sol–gel technology. The zirconia powder was crushed for 8 h and in conjunction with different molar proportions of boric acid, in this consider, a kinetic demonstrate for reactions creating ZrB2 was built up based on thermodynamic analysis. The resultant powder was synthesized in a neutral atmosphere controlled in 1450°C and 1550°C. After it was also observed that, with the increase of molar proportion of H3BO3, the reaction delivered ZrB2 powders in high amount of the boron reaction. The compound was analyzed by an X‐ray diffraction technique and found to be ZrB2 powder that was synthesized with the purity of approximately 98%.

Preparation of nanometer zirconia by hydrothermal method: Influence of temperature and mechanism

Monoclinic (m-ZrO2) and tetragonal zirconia (t-ZrO2) nanoparticles with average grain size of 22.8 nm were synthesized by hydrothermal method using zirconium oxychloride octahydrate (ZrOCl2·8H2O), urea (CO(NH2)2) and deionized water as zirconium source, precipitant, and solvent, respectively. The effects of CO(NH2)2 hydrolysis rate, hydrothermal temperature, and time on the crystal structure, morphology, and grain size were studied. The structure, morphology, grain size, and crystal phase of zirconium oxide (ZrO2) were characterized by X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Thermogravimetry (TG-DTA), and Fourier Transform Infrared spectroscopy (FT-IR). The results show that the formation mechanisms of different crystal forms can be controlled by the average pH value. The hydrolysis rate of CO(NH2)2 was relatively slow at 120 °C, resulting in a slower rate of OH− production. The lower average pH value favors the formation of m-ZrO2 through the dissolution precipitation mechanism. With the increase of crystallization temperature, the hydrolysis rate of CO(NH2)2 is accelerated, and the average pH value of the solution is increased, which is conducive to the structural rearrangement of [Zr(OH)8(H2O)16]8+ precursor to form tetragonal phase. In addition, the number of defect sites is directly proportional to the crystallization temperature. Extension of crystallization time helps the generation of ZrO2 crystals by polycondensation and directional growth.

Double positively charged polyamide nanofiltration membrane with PEI/Zr4+ for Cr3+ and trimethoprim removal

This paper focuses on the functionalization of double positively charged polyethylenimine (PEI)/Zr4+-polyamide (PA) nanofiltration (NF) membrane by connecting Zr4+ with positively charged PEI-PA NF membrane surface. In particular, the properties of prepared PEI/Zr4+-PA NF membrane, performance on removing aquatic contaminants (Cr3+ and trimethoprim), and its antifouling ability were evaluated in detail. In this regard, zirconium acetate was successfully adopted as the zirconium source for stable membrane surface charge control. Zr4+ loading increased the hydrophilicity of the PEI-PA NF membrane, improved permeate flux, and enhanced the removal behavior of PEI/Zr4+-PA NF membrane especially when exposed to Cr3+ and trimethoprim at high concentrations. Furthermore, effectiveness of PEI/Zr4+-PA NF membrane was not affected by high filtering degree, filtration cycle, and negatively charged macromolecules, such as bovine serum albumin (BSA). Also, antifouling ability of PEI/Zr4+-PA NF membrane could be further improved by continuously loading Zr4+.

Tetragonal Nanosized Zirconia: Hydrothermal Synthesis and Its Performance as a Promising Ceramic Reinforcement

In this study, we produced zirconia nanoparticles with a pure tetragonal phase, good dispersion, and an average particle size of approximately 7.3 nm using the modified hydrothermal method. Zirconium oxychloride (ZrOCl2-8H2O) was used as zirconium source, while propanetriol was used as an additive. The influence of propanetriol content, sonication time, hydrothermal temperature, and type of dispersant on the physical phase and dispersibility of zirconia nanoparticles was investigated. Monoclinic zirconia was found to completely transform into a tetragonal structure when the mass fraction of glycerol was increased to 5 wt%. With the increase in the mechanical stirring time under ultrasonic conditions, the size distribution range of the prepared particles became narrower and then wider, and the particle size became first smaller and then larger. Ultrasonic and mechanical stirring for 5 min had the best effect. When comparing the effects of different dispersants (PEG8000, PVP, and CTAB), it was found that the average particle size of zirconia nanoparticles prepared with 0.5 wt% PVP was the smallest. Furthermore, by adding different concentrations of pure tetragonal phase nanozirconia to 3Y-ZrO2 as reinforcement additives, the bending strength of the prepared ceramics increased first and then decreased with increasing addition amounts. When the amount of addition was 1 wt% and the ceramic was calcined at 1600 °C, the flexural strength of the ceramic increased significantly, which was about 1.6 times that of the unadded ceramic. The results are expected to provide a reference for the reinforcement of high-purity zirconia ceramics.

MOF-assisted synthesis of mesoporous zirconium phosphate for enhanced cadmium removal from water

It is unprecedently found that a zirconium-based metal-organic framework (MOF-808) can be a source of zirconium for the synthesis of zirconium phosphate (ZrP) with discrete disc nanocrystals (4.8 to 5.2 nm in size), normally obtained at high temperature or high phosphoric acid concentration. In contrast to the routinely obtained ZrP phase, the one derived from zirconium MOF under similar conditions offers dispersed particles with more active and accessible adsorption sites for efficient removal of cadmium. Indeed, the cadmium removal performance was found to be 88.27 mg/g compared to the conventional ZrP (67.48 mg/g) under the same conditions, bringing thus clear evidence of the virtues of using Zr-MOF as a template for the design of novel nanostructured materials with enhanced removal efficiency.

Hydrophobic Modification of ZrO2-SiO2 Xerogel and Its Adsorption Properties to Rhodamine B.

Zirconium nitrate pentahydrate (Zr(NO3)4·5H2O) and tetraethyl orthosilicate (TEOS) are used as the zirconium source and silicon source, respectively, and methyltriethoxysilane (MTES) as the hydrophobic modifier; the hydrophilic and hydrophobic ZrO2-SiO2 xerogels were prepared successfully. The xerogels were characterized using Fourier transform infrared spectra (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and N2 adsorption–desorption measurement. The adsorption mechanism of hydrophobic ZrO2-SiO2 xerogels to RhB was described by the kinetic and adsorption isotherms. The results showed that the introduction of Si-CH3 groups can make the average pore size, BET surface area, and total pore volume of ZrO2-SiO2 xerogel increase. The hydrophobic ZrO2-SiO2 xerogel displays an adsorption capacity of 169.23 mg·g−1 for RhB dye at 25 °C and pH = 3. The adsorption process of hydrophobic ZrO2-SiO2 xerogel to RhB followed a pseudo–second-order kinetic model. Fitting results from the D–R model of adsorption indicate that the adsorption of RhB onto the hydrophobic ZrO2-SiO2 xerogels is mainly physical, accompanied by a spontaneous heat absorption process. The regeneration and recycling properties of hydrophobic xerogels were investigated, and their recoverability and reusability were demonstrated.

Zirconium oxycarbides and oxycarbonitrides: A review

AbstractZirconium oxycarbides and zirconium oxycarbonitrides are high‐temperature ceramic materials with great potential for applications in advanced technologies due to their good refractoriness, mechanical and thermoelectric properties, and corrosion resistance. The properties of ZrCO(N) materials strongly depend on their composition. However, the stoichiometry of stable ZrCO(N) compounds, synthesis chemistry, and thermodynamics of the proceeding reactions require clarification. This review comprehensively interprets data for ZrCO and ZrCON ceramics, including studies that may not have been addressed in prior reviews. It summarizes the state‐of‐the‐art synthesis procedures involving reactions between commonly used zirconia, zirconium carbide, and carbon black, along with other zirconium sources widely used in the last few decades for the preparation of ZrCO(N) materials. The controversial reaction mechanisms of carbothermal reduction of zirconia and the role of CO gas in this process are discussed. The properties of ZrCO and ZrCON and their possible applications are also summarized.

Hydrothermal zircon: Characteristics, genesis and metallogenic implications

Zircon is a principal source of zirconium and hafnium, as well as a key mineral both for petrogenetic modeling and age dating. Although zircon occurrences have been reported from hydrothermal mineral systems, detailed studies on zircon that crystallized entirely from saturated hydrothermal fluid are rare. Here we report on hydrothermal zircon crystals dated at about 1911 Ma that crystallized from boiling high-salinity H2O-CO2 hydrothermal fluid with fluid inclusion homogenization temperatures of 295 to 325 °C and the corresponding pressure of 71 bar. These zircon crystals were then overprinted by two stages of hydrothermal zircon veins at 1864 Ma and 528 Ma. The zircon veins crystallized from boiling hydrothermal fluids of moderate to low salinities with fluid inclusion homogenization temperatures and the corresponding pressures of 302 to 329 °C and 75 bar and 290 to 320 °C and 70 bar, respectively. The zircon crystals in our study show sharp and regular cathodoluminescent oscillatory zonation and low and consistent trace element concentrations and Th/U ratios that decrease with fluid salinity. The Th/U ratios of these zircons lie between the magmatic zircon values (>0.5) and metamorphic zircon values (≤0.1). The rare earth element concentrations and trace element spidergram patterns of the zircon samples do not record their hydrothermal origin. Importantly, the low concentrations of HfO2 (<1%), Y (<400 ppm) and Ti (<4 ppm) can discriminate hydrothermal zircon from igneous and metamorphic zircons. Hydrothermal zircon is considered as an effective tool for the dating of mineral deposits and also represents one of the main sources of critical elements such as zirconium and hafnium.

Room temperature fabrication of oriented Zr-MOF membrane with superior gas selectivity with zirconium-oxo cluster source

Rational structural design and engineering of MOF membranes is particularly promising for energy-efficient gas separation. Preferred orientation manipulation delegates an effective approach to eliminate intercrystalline defects and therefore, improve their separation performance, while room-temperature (RT) synthetic protocol is quite beneficial to foster their industrial batch production. Nevertheless, it remains challenging to fabricate highly oriented MOF membranes at RT; simultaneously, the density of defective sites in the framework, which is assumed to exert significant influence on the separation performance relying on high affinity-interactions between guest molecules and coordinatively-unsaturated open metal sites, should be deliberately tailored. In this study, we achieve RT synthesis of highly (111)-oriented UiO-66 membrane exhibiting high defect density in the framework through employing Zr6O4(OH)4(OAc)12 clusters as zirconium source during epitaxial growth. Prepared UiO-66 membrane manifests an ideal CO2/N2 selectivity of 46.2, which represents the highest value among all pure MOF membranes tested in comparable operating conditions. It is anticipated that the above protocol can be further expanded for facile and mild preparation of state-of-the-art MOF membranes.

Nanocrystalline ZrC coated graphite and its effect on mechanical properties and thermal shock resistance of low-carbon Al2O3–C refractories

Nanocrystalline ZrC coated graphite was synthesized in mixed molten salt system, and the effect of different zirconium sources and reaction temperature on its synthesis was studied. The effects of nanocrystalline ZrC coated graphite on the microstructure, thermal shock resistance and cold mechanical properties of low-carbon Al2O3–C refractories in different atmospheres were studied. The results indicated that nanocrystalline ZrC coated graphite synthesized by Zr powder had a more uniform coating structure than ZrO2 as a zirconium source, and increasing the reaction temperature was beneficial for the synthesis of ZrC. The sample with nanocrystalline ZrC coated graphite fired in nitrogen atmosphere had better mechanical properties, the cold modulus of rupture was 15.67% and 50.67% higher than that of the samples fired under argon atmosphere and carbon-embedded atmosphere, respectively. Meanwhile, Sialon played a significant role in improving the mechanical properties of the samples after thermal shock. In addition, the treatment in argon or carbon-embedded atmosphere was beneficial in improving the thermal shock resistance of the samples.

Adsorption of CO2 by a novel zeolite doped amine modified ternary aerogels

Novel amine functionalized materials can capture greenhouse gas CO2. In this study, SiO2–Al2O3–ZrO2 ternary composite aerogel was prepared by sol-gel method, supercritical drying, ultrasonic non-in-situ synthesis and other processes using aluminum chloride hexahydrate as aluminum source, ethyl orthosilicate as silicon source and tetrabbutyl zirconate as zirconium source. The composite material was used as the carrier material. By impregnation method, the modified agent bis - (3-trimethoxy-silpropyl) amine and the composite were fully mixed and modified, and the novel zeolite doped amine functionalized ternary composite aerogel was obtained by doping acidification activation zeolite. The results show that the prepared novel zeolite amine-modified ternary aerogels have rich microporous structure and ordered mesoporous structure. After loading different contents of amine-based materials (CAA-X) in the ternary aerogels, the comparison between CAAZ-X and zeolite amine-modified ternary aerogels is conducted. Zeolite doped CAAZ-30 material shows the best adsorption performance, with a maximum adsorption capacity of 5.30 mmol/g. In the presence of water vapor, CAAZ-30 material also showed the best adsorption performance, with a maximum adsorption capacity of 5.33 mmol/g. This can help us design suitable adsorbent materials for CO2 capture in different practical applications.

Minerals explained 62

Eudialyte is a mineral unfamiliar to most people. This is likely to change in the near future, as this mineral is of increasing economic importance. Eudialyte is now known to be one of a group that has grown in number to a remarkable extent in recent years, and eudialytes are index minerals for a specific category of igneous rocks and are repositories for elements, such as the rare earths, which have become increasingly critical to modern technology. The eudialyte group now comprises about 50 members of which about 29 members are fully recognized, and exploitation of eudialyte group minerals will soon be a reality. The mineral's name comes from Greek: Eu διάλυτος, meaning ‘well decomposable’—a reference to the fact that, unlike the highly refractory zircon (the common source of zirconium), eudialyte is soluble in common acids, making it relatively cheap to work.