ZrOCl2 Research Articles

Fabrication of porous ZrO2 hollow sphere and its adsorption performance to Congo red in water

Hollow and solid ZrO2 microspheres with mesoporous structures were prepared by a hydrothermal method using zirconium oxychloride and urea as precursors. The as-prepared samples were characterized by X-ray diffraction, scanning and transmission electron microscopy and nitrogen adsorption–desorption isotherms. Adsorption performance of the as-prepared samples toward Congo red (CR) aqueous solutions was investigated and discussed. The pore structure analyses indicated that the prepared ZrO2 hollow and solid microspheres contained bimodal porous organization: small mesopores (ca. 2nm) and large mesopores and macropores (ca. 40–70nm). The CR equilibrium adsorption data of the as-prepared samples were fitted using Langmuir and Freundlich equations, indicating that the Langmuir equation exhibited the better correlation of the experimental data. The CR adsorption capacities were determined by the Langmuir equation and found to be 59.5, 21.4 and 4.8mgg−1 for the ZrO2 hollow, solid microsphere and reagent samples, respectively. Adsorption data were further modeled by the pseudo-first-order, pseudo-second-order and intra-particle diffusion kinetics equations. The results suggested that pseudo-second-order kinetic and intra-particle diffusion equations could better describe the kinetics of CR adsorption. The prepared ZrO2 hollow microsphere was found to be good adsorbent for the CR removal from water due to its high specific surface areas and bimodal porous structures.

Preparation and Characterization of Ultra-Fine ZrB<sub>2 </sub>by Sol-Gel Method

Ultra-fine ZrB2 powders were synthesized by sol-gel carbothermal processing using zirconium oxychloride (ZrOCl2.8H2O), boric acid (H3BO3) and sucrose (C12H22O11) as raw materials. Additionally, mannitol was used as cosolvent to obtain a stable high-concentration ZrB2 sol. Since C12H22O11 can be completely decomposed to carbon, carbon might be accounted precisely for the carbothermal reduction reaction. In the case of C/Zr(mol.)=6.0 and B/Zr(mol.)=3.0, a single phase ZrB2 without residual ZrO2 or ZrC was obtained. The photomicrograph revealed a spheres shape morphology with an uniform size distribution.

Nanometer-sized Polynuclear Cluster and Oxide Nanocrystal Formation via Aging-condition-dependent Hydrolysis of Zirconium Oxychloride

Abstract Aqueous solutions of zirconium oxychloride aged at temperatures between 298 and 333 K for 0–26 days were investigated. Nanoparticles with different size distributions depending on aging temperature and duration were detected by dynamic light-scattering measurements. Extended X-ray absorption fine structure analysis and scanning transmission electron microscopy measurements revealed the nanoparticles formed in the samples to be zirconium polynuclear complexes and zirconium dioxide nanocrystals under mild condition, which was previously unexplored.

Hydrothermal Synthesis of Steady-State Zirconium (Iv) Oxide

Influence of admixtures of yttrium (III) oxide and adipic acid on phase composition and extraction degree of zirconium (IV) oxide in the process of hydrothermal treatment of aquatic solution of zirconium (IV) oxychloride is studied.

Doping effects of B in ZrO2 on structural and catalytic properties of Ru/B-ZrO2 catalysts for benzene partial hydrogenation

The B-doped ZrO2 (B-ZrO2) samples with different B/Zr ratios were synthesized using zirconium oxychloride and boric acid as the precursors. Their crystallographic phase retained as tetragonal ZrO2 after the doping of B; however, the amount of the Lewis acid sites increased from 46.1μmolNH3g−1 on ZrO2 to 100.6μmolNH3g−1 on B-ZrO2(1/10) with the nominal B/Zr molar ratio of 1/10. The Ru/B-ZrO2 catalysts were then prepared by chemical reduction, and their electronic and structural properties were systematically characterized by spectroscopic techniques. It is identified that the Ru nanoparticles (NPs) supported on these B-ZrO2 samples exhibited similar size, chemical state, and microstructure. In the partial hydrogenation of benzene, the turnover frequency of benzene was linearly proportional to the amount of the acid sites on the supports, whereas the selectivity toward cyclohexene displayed a volcanic evolution passing through a maximum of 88% on the Ru/B-ZrO2(1/15) catalyst. Kinetic analysis indicated that the acid sites improved the rate constants of the benzene to cyclohexene step (k1) and the cyclohexene to cyclohexane step (k2) to different degrees. The resulting k1/k2 ratio increased from 3.7×10−2lmol−1 (Ru/ZrO2) to 4.8×10−2lmol−1 (Ru/B-ZrO2(1/15)), and then declined to 4.1×10−2lmol−1 (Ru/B-ZrO2(1/10)), which explained the volcanic evolution of the selectivity toward cyclohexene with respect to the acid amount.

Removal of silicon in acid leaching and flocculation processes during zirconium oxychloride octahydrate production

The efficiency of silicon removal technology by acid leaching and flocculation during zirconium oxychloride octahydrate (ZrOCl2⋅8H2O) production has been improved. The optimum conditions of acid leaching were found to be as follows: transiton material, 300g; HCl (6mol/L), 600mL; leaching time, 4h; and leaching temperature, 100°C. The nonionic polyoxyethylene lauryl ether (AEO9) was adopted as the flocculant. The optimum flocculation conditions were found to be as follows: temperature, 40°C; flocculant amount, 10ml (concentration 1%); time, 1h. The zirconium oxychloride solution after purification contained 36ppm SiO2 and 160g/L ZrOCl2. The polymerization and flocculation mechanisms of silicic acid were analyzed. Results of Fourier-transform infrared, scanning electron microscopy, nuclear magnetic resonance, and Brunauer–Emmett–Teller analyses showed the main transformation and properties of the products in the acid leaching and flocculation processes.

Inclusion of L-Alanine, L-Arginine, L-Aspargine, L-Serine and Proline into θ-Type Zirconium Phosphate

zirconium oxychloride in HF solution with dilute H3PO4 at 15 0 C. The resulting compound was intercalated with amino acids L-alanine, L-arginine, L-aspargine, L-serine and proline respectively at room and 600C temperatures. The structure properties of the obtained products were characterized by fourier transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD) and thermal analysis (TG/DTA). FT-IR spectrum results demonstrated that the effectiveness of the vibrational spectra in characterizing of the resultant product was supported by TG/DTA and X-ray analysis. Moreover, the vibrational spectroscopic investigation shows that water molecules were appeared very characteristic infrared bands that can be assigned to regular hydrogen bonding of each molecule to adjacent OH group of (POH). Furthermore, amino acids inclusion products were found to retain the layered structure and the loading are closely dependent on the nature of the amino acid.

A novel voltammetric p-nitrophenol sensor based on ZrO2nanoparticles incorporated into a multiwalled carbon nanotube modified glassy carbon electrode

Electrochemical fabrication of a functionalized multiwalled carbon nanotube/ZrO2nanocomposite film on the surface of a glassy carbon electrode.

Catalysts for enantioselective Biginelli reaction based on the composite silica-zirconia xerogels prepared using different zirconium sources

The composite silica-zirconia xerogels have been prepared via sol–gel method using zirconium oxychloride, oxynitrate, acetate and sodium silicate as the precursors. The prepared materials have been characterized using FTIR, TG/DTA, EDX and surface area analyses. It has been established that surface area of silica-zirconia xerogels significantly depends on the zirconium source, but phase transitions and structural features of the xerogels seem to be unaffected by the choice of the zirconia precursor. Prepared xerogels increase the activity of chiral inductor in the asymmetric Biginelli reaction. The anion of the zirconium salt adsorbed on the surface of the synthesized material and the presence of Si–O–Zr heterolinkages determines the reaction yield. The highest chemo- and enantioselectivity towards formation of ee isomer have been provided by the catalyst prepared from zirconium oxychloride.

In situ electrochemical synthesis of highly loaded zirconium nanoparticles decorated reduced graphene oxide for the selective determination of dopamine and paracetamol in presence of ascorbic acid

Highly loaded zirconium oxide (ZrO2) nanoparticles were supported on graphene oxide (ERGO/ZrO2) via an in situ, simple and clean strategy on the basis of the electrochemical redox reaction between zirconyl chloride and graphene oxide (ZrOCl2 and GO). The electrochemical measurements and surface morphology of the as prepared nanocomposite were studied using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and field emission scanning electron microscopy (FESEM). This ZrO2 decorated reduced graphene oxide nanocomposite modified GCE (ERGO/ZrO2) exhibits a prominent electrocatalytic activity toward the selective detection and determination of dopamine (DA) and paracetamol (PA) in presence of ascorbic acid (AA). The peaks of linear sweep voltammetry (LSV) for DA and PA oxidation at ERGO/ZrO2 modified electrode surface were clearly separated from each other when they co-existed in the physiological pH (pH 7.0) with a potential value of 140mV (between AA and DA) and 330mV (between AA and PA). It was, therefore, possible to simultaneously determine DA and PA in the samples at ERGO/ZrO2 nanocomposite modified GCE. Linear calibration curves were obtained for 9–237μM of PA and DA. The ERGO/ZrO2 nanocomposite electrode has been satisfactorily used for the determination of DA and PA in the presence of AA at pharmaceutical formulations in human urine samples with a linear range of 3–174μM. The proposed biosensor shows a wide linear range, low detection limit, good reproducibility and acceptable stability, providing a biocompatible platform for bio sensing and bio catalysis.

Stabilization of the Metastable Tetragonal Phase in Zirconia Nanopowders Synthesized via Polyacrylamide Gel Method

In this work, the possibility of synthesizing stable tetragonal zirconia nanopowders via polyacrylamide gel method was investigated. In addition, the effects of the sulfation process on the stabilization of metastable tetragonal structure and tetragonal to monoclinic phase transformation were studied. Zirconium oxychloride and zirconium oxynitrate salts were used as the initial salt precursor and the calcination procedure was performed at different temperatures (650–850 °C) for 2 h with heating and cooling rates of 5 and 2 °C/min. The results showed that in the synthesized powders from zirconium oxynitrate, metastable tetragonal phase was stable up to 850 °C. Moreover, heating rate of 5 °C/min was concluded as the optimum rate to stabilize the metastable tetragonal phase up to higher temperatures. The addition of sulfate ions into the structure of sulfated zirconia powders synthesized by zirconium oxychloride retarded the tetragonal to monoclinic phase transformation, while in the case of zirconium oxynitrate, this phase transformation was accelerated.

Ultrasound-assisted one-pot synthesis of dihydropyrimid-2-one/thiones catalyzed by zirconyl chloride hexahydrate

Ultrasound-assisted one-pot synthesis of dihydropyrimid-2-one/thiones catalyzed by zirconyl chloride hexahydrate

Preparation and characterization of ZrO2/PES hybrid ultrafiltration membrane with uniform ZrO2 nanoparticles

In current or next-generation reuse systems, the development of new classes of antifouling membranes is needed before viable membrane-based approaches for wastewater reclamation can be achieved. In this study, ZrO2/PES hybrid ultrafiltration membranes with uniform ZrO2 nanoparticles were prepared by combining an ion-exchange process with a traditional immersion precipitation process. Hydrous ZrO2 sol was synthesized by addition of anion-exchange resin in N,N-dimethylformamide solvent containing zirconyl chloride. Homogeneous ZrO2/PES casting solution was then obtained by dissolving PES polymer in the ZrO2 sol. The existence and dispersion states of ZrO2 nanoparticles in the resultant membrane matrix were examined by X-ray photoelectron spectrometer, thermogravimetric analysis, scanning electron microscope and transmission electron microscope. The results indicate that the ZrO2 nanoparticles were well dispersed throughout the PES matrix and the diameter of the formed nanoparticles was about 5–10nm. The hydrophilicity of the membranes was determined by measuring the contact angles. The antifouling property was determined by antifouling experiments and atomic force microscopy. The results confirm that the existence of ZrO2 nanoparticles improves the hydrophilicity and reduces protein adsorption of membranes.

Synthesis and characterization of hexagonal zirconium phosphate nanoparticles

Abstracts A facile synthesis of zirconium phosphate (ZP) nanoparticles was studied using polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP), stoichiometric amounts of zirconyl chloride and phosphoric acid. It was performed in acidic medium via precipitation. After calcinations of PVA/ZP and PVP/ZP at 550 °C for 4 h, pure ZP nanoparticles with hexagonal shape were obtained. H-bonds between ZP and PVA or PVP along polymer chains, play an important role in the dispersion of in situ prepared ZP. The formation of ZP nanoparticles was investigated by means of XRD, FT-IR, SEM and TEM. The particles were well dispersed and the mean sizes are about 60 nm.

Honeybee-collected pollen from Transylvania: palynological origin, phenolic content and antioxidant activity

. Palynological analysis, total polyphenols, total flavonoids and antioxidant activity were studied on six samples fresh bee pollen from Transylvania. Floral origin of used bee collected pollen was identified by palynological analysis without acetolysis followed by microscopy and comparison with a library of samples. The content of total polyphenols was determined using the Folin-Ciocalteu colorimetric method with gallic acid as standard and total flavonoids content was determined with zirconium oxychloride reagent using quercetin as standard for calibration. The antioxidant properties were evaluated by 2,2-diphenyl-picrylhydrazyl radical scavenging capacity (DPPH) assey and ferric ion reducing antioxidant power assey. A great variability regarding the content of total polyphenols of examined bee pollen samples with different botanical origin and the antioxidant capacity was found.

Synthesis of zirconium diboride nano-powders by novel complex sol–gel technology at low temperature

Zirconium diboride nano-powders were synthesized by novel complex sol–gel technology at low temperature. Zirconium oxychloride as source of zirconium was complexed via adding propylene oxide that could form the stable zirconium sol by protonation and ring-opening reactions and boric acid as source of boron was dissolved effectively using glycerol that acted as complexing agent to create the boron network through forming stable coordination compound. Additionally, glycerol could be carbonized as source of carbon, which could replace the conventional carbon source additives. Then the mixed sols were gelated, dried, and exposed to 1,450 °C for 2 h with flowing argon in the furnace. High purity of ZrB2 nano-powders with spherical shape of ca. 200 nm were synthesized via carbothermal reduction. The mechanism of two complexing agents were discussed combining with the infrared spectroscopy analysis results, and the powder characteristics were performed by using X-ray diffraction and transmission electron microscopy.

Effect of Graphene in Enhancing the Photo Catalytic Activity of Zirconium Oxide

Graphene, have two-dimensional structure with high conductivity, extremely high specific surface area and superior electron mobility etc. It has been regarded as an important synthesis material for various composite materials used in many applications. Especially, graphene-based semiconductor photo catalysts have attracted extensive attention because of their usefulness in environmental applications such as air cleanup, water disinfection, hazardous waste remediation, and water purification. The present study involves the photo catalytic degradation of methyl orange by photo catalytic process using different concentrations of ZrO2/graphene synthesized at different annealing temperature. A series of zirconium oxide (ZrO2, zirconia) and graphene (Gr) composites with different contents of Gr (5.7, 7.3, 8.3 %) in the composite were synthesized using zirconium oxychloride (ZrOCl2·8H2O) and graphene oxide as the starting materials. The photocatalytic activities of the synthesized composites were measured for the degradation of methyl orange dye with UV spectroscopy. The rate of decolorization was recorded with respect to the change in intensity of absorption peaks for methyl orange. The absorption peaks, diminished and finally disappeared during reaction, indicating that the dye had been degraded. The photocatalytic activity is strongly affected by the concentration of graphene in the ZrO2. The synthesized ZrO2/graphene photocatalysts are characterized by X-ray diffraction, TGA, Raman spectroscopy and UV–Visible spectroscopy. Finally, it has been concluded that graphene when employed as catalytic support for ZrO2 boost its photo catalytic efficiency. Effect of graphene on photo catalytic activity of ZrO2 anneal at 1,000 °C.

Chemical Modification of Palm Fibres Surface with Zirconium Oxychloride

Chemical modification of natural fibres has been carried out using different methods for such purposes as reinforcement in polymer matrices and heavy metals adsorption. In this work, palm fibres were modified by zirconium oxychloride in situ. The palm fibres that had been chemically modified were compared to those in nature using fibres that passed through 20 and 40 mesh screens to evaluate the influence of particle size on modification. Palm fibres were modified with ZrO2.nH2O nanoparticles through the use of zirconium oxychloride in an acidic medium in the presence of palm fibres using ammonium solution (1:3) as the precipitating agent. Scanning electron microscopy (SEM), X-ray diffraction (XRD), infrared spectrophotometry (FTIR), and atomic emission spectrometry with inductively coupled plasma (ICP-AES) were used to characterize the hybrid materials. Results indicated that the particle size of the palm fibres influenced in the modification, because the fibres with smaller particle size had a greater deposition of inorganic material. The ICP technique revealed an increase of 21% nanoparticles ZrO2.nH2O deposited on fibres (40 mesh) when compared to fibres (20 mesh). The diameter of nanoparticles ZrO2.nH2O deposited on fibres was about 50 to 220 nm, as observed by SEM.

The photocatalytic degradation of carbamazepine and prediction by artificial neural networks

The three layer artificial neural network model was applied to predict the degradation efficiency for carbamazepine in photocatalytic oxidation under UV radiation. Titania–zirconia was employed as a catalyst for the photooxidation. The catalyst was prepared using titanium isopropoxide and zirconium oxychloride by sol–gel method and characterized by transmission electron microscopy and BET analysis. Different process parameters such as, initial concentration of carbamazepine, pH of the solution, catalyst concentration and time of UV irradiation were employed as the input to the artificial neural network model and the output of the network was degradation efficiency of carbamazepine. The multilayer feed-forward networks with the Levenberg–Marquardt (trainlm) backpropagation training algorithm was used for the network training. The smallest mean square error was obtained for three-layer network with ‘logsig’ transfer function and five neurons in the hidden layer gave optimal results. A comparison between the predicted values and selective experimental data of degradation efficiency showed a high correlation coefficient (R2) of 0.997.

Effects of ZrO2interphase on mechanical and microwave absorbing properties of SiCf/SiC composites

Zirconia (ZrO2) coatings were successfully prepared on KD-II SiC fibers by sol–gel approach in zirconyl chloride and ethanol–water solution. Subsequent heat treatment at 1000 °C was done in vacuum. Phase composition and morphological characteristics of the ZrO2 coatings were investigated by XRD, FTIR, and SEM. The SiCf/SiC composites with ZrO2 coatings as interphase were fabricated by chemical vapor infiltration (CVI). The effects of ZrO2 interphase on the mechanical and dielectric properties of composites were studied. The results show that the flexural strength of SiCf/SiC composites with and without ZrO2 interphase are 261 and 103 MPa, respectively. It is demonstrated that ZrO2 interphase can effectively adjust the interfacial bonding strength and improve the mechanical properties of SiCf/SiC composites. In addition, both the real and imaginary parts of the complex permittivity (ϵ′ and ϵ″) of the SiCf/SiC composites with ZrO2 interphase are higher than those of without ZrO2 interphase. The effective absorbing bandwidth (below −10 dB) of SiCf/SiC composites with ZrO2 interphase is 1.6 GHz and the lowest reflection loss is −11.5 dB when the sample thickness is 2.7 mm.