Zirconium Hydroxide Research Articles

Integration of high strength, resilience and stretchability into the nanocomposite hydrogel sensor for a wide working range detection and underwater sensing

Hydrogel sensors have drawn tremendous attention due to the combination of stretchability, biocompatibility, and convenient production. The integration of high mechanical strength, stretchability and a wide working range towards various application environment is still a great challenge. Herein, both the tough and highly stretchable hydrogel sensor was developed and showed large working range and good sensing capability towards various deformation and underwater motions. The hydrogel was constructed by the polymerization of acrylic acid, acrylamide and N, N-dimethyl acrylamide, and crosslinked by the zirconium hydroxide. The obtained hydrogel exhibits high mechanical strength (∼1.5 MPa), strain (∼1400%) with good toughness (∼12 MJ/m−3), recovery properties and high elasticity (G’∼23 KPa) which was beneficial for the stable sensing performance. It also showed high sensitivity in a wide working range (0–1300%), and exhibited stretching-dependent resistance signal monitoring capability on large, small, cyclic deformations, and various human motions (wrist, finger bending and swallowing). Moreover, it can detect various motions underwater, even monitor the pulse beating for healthcare in the liquid environment. This hydrogel with these comprehensive mechanical and sensing performances has great potential in the fields of artificial intelligence and electric skins, and further applied in the aquatic environment.

Sustainable functionalized smectitic clay-based nano hydrated zirconium oxides for enhanced levofloxacin sorption from aqueous medium

In this study, the functionalized smectitic clay (SC)-based nanoscale hydrated zirconium oxide (ZrO-SC) was successfully synthesized and utilized for the adsorptive removal of levofloxacin (LVN) from an aqueous medium. The synthesized ZrO-SC and its precursors (SC and hydrated zirconium oxide (ZrO(OH)2)) were extensively characterized using various analytical methods to get insight into their physicochemical properties. The results of stability investigation confirmed that ZrO-SC composite is chemically stable in strongly acidic medium. The surface measurements revealed that ZrO impregnation to SC resulted in an increased surface area (six-fold higher than SC). The maximum sorption capacity of ZrO-SC for LVN was 356.98 and 68.87 mg g−1 during batch and continuous flow mode studies, respectively. The mechanistic studies of LVN sorption onto ZrO-SC revealed that various sorption mechanisms, such as interlayer complexation, π-π interaction, electrostatic interaction, and surface complexation were involved. The kinetic studies of ZrO-SC in the continuous-flow mode indicated the better applicability of Thomas model. However, the good fitting of Clark model suggested the multi-layer sorption of LVN. The cost estimation of the studied sorbents was also assessed. The obtained results indicate that ZrO-SC is capable of removing LVN and other emergent pollutants from water at a reasonable cost.

Boosting peroxymonosulfate activation by a novel bifunctional core-shell nanoreactor MnFe2O4@HZO for nitrilotris-methylenephosphonic acid removal

Advanced oxidation processes (AOPs) struggle to entirely remove phosphonates from wastewater, and the remaining phosphates easily cause secondary pollution. With MnFe2O4 as the core and hydrated zirconium oxide (HZO) as the shell, the magnetic core-shell nanoreactor MnFe2O4 @HZO with dual functions of "catalysis and adsorption" was designed to activate peroxymonosulfate (PMS) for nitrilotris-methylenephosphonic acid (NTMP) removal. Total phosphorus removal reached 96.5% within 180 min, with only 0.18 mg/L of phosphates left because of the full exploitation of active sites and adsorption sites. This is because of the strong inner-sphere complexation of shell for phosphates adsorption and the excellent electron transfer performance of the core for PMS activation. High NTMP removal under the protection of HZO shell could be obtained over wide pH (3−8) or complex water matrices. After five cycles, Mn leaching amount was only 0.4 mg/L. The study provides information on the design of core-shell catalysts in the PMS-AOP field for the comprehensive removal of contaminants.

Steering Electron Density of Zr Sites Using Ligand Effect in Bio‐Beads for Efficient Defluoridation

AbstractBecause of spontaneous agglomeration effect and undesirable electronic state of Zr sites on the surface, zirconium (hydro)oxides generally exhibit suboptimal defluoridation capacity. Herein, a template confinement‐ligand anchoring strategy is developed by utilizing confined growth of zirconium hydroxide (ZH) inside chitosan hydrogel beads (CHB) and subsequent anchoring of fumaric acid (fm) on its surface Zr sites in a monodentate mononuclear coordination mode. This technique leads to uniform dispersion of ultrafine fmZH (≈3.4 nm) and tunable electron density at the Zr sites. Due to the electron‐withdrawing ability of fm, electron‐delocalized Zr sites increase the orbital energy level matching and vacate Zr 4d orbitals to promote hybridization with the F 2p orbitals. Ultimately, robust ZrF bond can be formed as a result of reduced the adsorption energy toward fluoride ions. The defluoridation capacity shows positive linear relationship with the electron extraction ability of ligands. The saturation adsorption capacity and dynamic treatment capacity of CHB@fmZH are 10.8 and 45.9 times higher than that of CHB@ZH, respectively, owing to high electron extraction (0.098 e−) of fm. This study offers a novel insight into the design and synthesis of high‐efficiency metal oxide adsorbents by steering its surface metal sites’ electronic state through ligand effect.

Rationale for development of high surface zirconium hydroxide: Synthesis route and mechanism discussion

In this work, xerogels of zirconium hydroxide were synthesized by the CDJP method at constant pH values from 3 to 8. The effect of precipitation pH and treatment conditions on the properties of xerogels was studied. It was found that all unwashed xerogels contain zirconium-bound nitrate ions and their amount systematically decreases as the precipitation pH increases. A high content of zirconium-bound nitrate ions cause the formation of Brønsted acid sites due to olation/oxolation processes which results to decrease in the specific surface. Washing and hydrothermal treatment have a greater effect on the surface properties of xerogels compared to the precipitation pH. Removal of zirconium-bound nitrate ions provides a significantly increase in the specific surface (up to 580 m2/g). Meanwhile hydrothermal treatment without washing leads to decrease in specific surface. The formation mechanisms of the high surface zirconium hydroxide xerogels was proposed and discussed.

Anion exchange on hydrous zirconium oxide materials: application for selective iodate removal.

The radioactive 129I is a top-priority radionuclide due to its the long half-life (1.57 × 107 years) and high mobility. Because of the planned and accidental releases to the environment, specific separation technologies are required to limit the potential radiation dose to human beings. Zirconium oxides are known for their adsorption capability and selectivity to oxyanions and here the applicability to selective IO3 - removal has been investigated regarding the uptake mechanism, regeneration and competition caused by other anions, like environmentally relevant SO4 2-. Granular aggregates of hydrous zirconium oxides with and without Sb doping showed high potential for the selective IO3 - removal in the presence of competing anions, like the forementioned SO4 2- (apparent capacity between 0.1-0.4 meq g-1 depending on SO4 2- concentration). The main uptake mechanism was found to be outer-sphere complexation (ion-exchange) to the protonated hydroxyl groups of hydrous zirconium oxides, but also minor mechanisms were identified including inner-sphere complexation and reduction to I-. The materials were observed to be easily and successively regenerated using dilute acid. Hydrous zirconium oxides showed high potential for IO3 - removal from waste solutions regarding technical (high selectivity and apparent capacity) and ecological/economic (feasible regeneration) aspects.

Диафрагма и мембрана для щелочного электролиза воды с гидрогелем гидроксида циркония в качестве гидрофильного наполнителя

The paper presents data on a new type of separation materials for alkaline water electrolyzers: a diaphragm synthesized by the phase inversion method and a multilayer microfilm membrane with zirconium hydroxide hydrogel as a hydrophilic filler. Experimental data are presented on their porosity, electrical conductivity, gas density, as well as the results of their tests as part of an alkaline electrolyzer battery in comparison with a porous diaphragm based on polysulfone with a hydrophilic filler (TiO2), synthesized by the traditional method of phase inversion. The advantages and disadvantages of new materials are determined, the ways of further research and development are determined.

Hydrophilic fillers for anione exchange membranes of alkaline water electrolyzers

Alkaline water electrolysers are widespread in many industries, including systems with hydrogen cycle of energy storage. One of the problems of modern alkaline water electrolysers is insufficient purity of generated electrolysis gases relative to electrolysis systems with solid-polymer electrolyte. In this regard, work on modification of existing porous diaphragms is actively carried out. One new area of research is the impregnation of new hydrophilic fillers into the composition of existing diaphragms and the transition to ion-solvate membranes. In this work the synthesis of zirconium hydroxide hydrogel inside a porous diaphragm with the hydrophilic filler TiO2 was carried out. This synthesis makes it possible to obtain a membrane with anion-exchange properties. A possible mechanism of OH- hydroxyl ion transfer by immobilized K+ ion was also proposed. The obtained results demonstrated the resistance of the membrane to concentrated alkaline solutions.

Optimizing lactic acid production for agricultural wastes revalorization via sugars hydrothermal conversion with zirconia-based catalysts: response surface methodology

The hydrothermal conversion of a complex sugars solution comprising glucose, arabinose, and xylose with zirconia-based catalysts to produce lactic acid (LA) was studied. Catalysts were synthesized by a simple template-assisted sol–gel method. Alternative template removal procedures, such as refluxing ethanol extraction, were compared to the conventional direct calcination. The catalyst obtained after ethanol extraction (Z-Ex) reported the highest specific surface area (323 m2 g−1), total pore volume (0.21 cm3 g−1) and density of acid sites (1.111 µmol m−2), with a significant contribution of strong acid sites. On the other hand, template removal by thermal treatment transformed the hydrous zirconia into crystalline tetragonal phase, reducing the specific surface area and removing most of the acid sites. Catalytic tests were carried out in a stirred batch reactor, resulting Z-Ex the most selective towards LA production. A four-factor experimental design was performed for Z-Ex catalyst by varying temperature, reaction time, initial pressure, and catalyst/reactants ratio. Results were analyzed using the response surface methodology (RSM) to maximize the LA production. A molar yield of 61.2% towards LA and complete sugars conversion were reached at optimized operating conditions: 189 °C, 208 min, 0.5 g catalyst g−1 reactants, and 10 bar N2. Additionally, fitting models for main by-products molar yields (furans, glyceraldehyde, glycolic, formic, acetic, and levulinic acids) were obtained with good accuracy prediction. All responses were jointly studied to understand the reaction mechanisms involved in generation of intermediaries and undesired degradation products.Graphical Abstract

Structural Approach to Understanding the Formation of Amorphous Metal Hydroxides.

This study investigates the formation of amorphous tetravalent metal hydroxides, M(OH)4, based on the structural analysis by small- and wide-angle X-ray scattering (SWAXS) and on the electrical potential charge near the surface of M(OH)4 particles. The amorphous zirconium hydroxide solid phases that aged in NaCl and CaCl2 solutions at 25 °C exhibited a hierarchical structure consisting of primary particles of a few nanometers in size and their aggregates more than 100 nm in size. The SWAXS profiles suggested that the size of the primary particles depends on the ionic strength and electrolytes in the sample solutions. The smaller size of the primary particles observed in solutions with higher ionic strength can be explained by the thinner electrical double layer. Additionally, we focused on the ζ potentials of M(OH)4 suspensions in NaCl, NaNO3, and CaCl2 solutions. With the aid of reference systems of metal oxides, MO2, it was found that the ζ potentials were well interpreted by a traditional surface ionization and complexation model, and the size distributions of large aggregates were explained by the classical Derjaguin-Landau-Verwey-Overbeek (DLVO) theory with the ζ potential values. The present study suggests the formation mechanism of amorphous metal hydroxides through a combination of structural analysis and investigation of electrical potentials.

Hydrothermal synthesis and sorption performance to Cs(I) and Sr(II) of zirconia-analcime composites derived from coal fly ash cenospheres

The paper is concerned with (i) the hydrothermal synthesis of hydrous zirconium dioxide (HZD) bearing analcime (HZD-ANA, zirconia-analcime) and (ii) its sorption properties with respect to Cs+ and Sr2+. The HZD-ANA particles were synthesized from coal fly ash cenospheres composed of aluminosilicate glass with (SiO2/Al2O3)wt.=3.1 and characterized by PXRD, SEM-EDS, STA, and low-temperature N2 adsorption. The non-radioactive simulant solutions of different acidity (pH=2–10) and Cs+/Sr2+ content (0.5–50.0 mg/L) were used in the work. The effect of synthesis conditions on the HZD-ANA particle size, zirconia content and localization as well as the sorption behavior with respect to Cs+ and Sr2+ (capacity, KD) were clarified. It was found that the small-sized HZD-ANA composites surpasses the Zr free analcime and large-sized HZD-ANA material in the Cs+ and Sr2+ sorption parameters (KD ~104–106 mL/g). The conditions to synthesize the zirconia-analcime composite of the highly enhanced sorption ability with respect to Sr2+ (KD ~106 mL/g) were determined. The high-temperature solid-phase re-crystallization of Cs+/Sr2+-exchanged HZD-ANA composites was shown to occur at 1000 °C resulting in a polyphase system based on nepheline, tetragonal ZrO2, and glass phase.

The Effect of sintering agent (Y2O3 and TiO2) from Bangka senotyme sand and ilminite on conductivity characteristics of zircon ceramic

Zircon has potential as a reliable ceramic material because it has good physical properties, including low thermal conductivity, low coefficient of thermal expansion and high mechanical resistance to heat can be used for various purposes such as household appliances, industry, electronics, refractories, to aerospace technology. In its application, zircon needs to beformed into solid ceramics. The formation of zircon ceramics can be carried out by hydrothermal and solgel methods at a sintered temperature of 1500°C based on hydrous zirconia and amorphous silica. This research is focused on the synthesis of zircon ceramics with varioussintering agents Y2O3 and TiO2 from the tailings processing of Bangka tin mining. The synthesiswas carried out with the basic material, namely zircon powder extracted from natural zirconsand. The characterization that will be carried out is the XRD structure as well as the mechanicaland electrical properties in the form of ceramic density and hardness as well as conductivity. Inthis study, it is hoped that a good zircon ceramic will be obtained.

Facile synthesis of lattice-defective and recyclable zirconium hydroxide coated nanoscale zero-valent iron for robust arsenite removal

A novel core-shell structured adsorbent, zirconium hydroxide coated nanoscale zerovalent iron (NZVI@Zr(OH)4), was developed for aqueous arsenite (As(III)) removal. The effects of water content and Zr dose for the coating process on the coating efficiency, anti-corrosion stability, and As(III) removal were investigated to optimize the performance of NZVI@Zr(OH)4. The Zr(OH)4 shell with a coating ratio of 200 wt% (Zr/Fe) was demonstrated to completely cover the NZVI surface, which can protect the NZVI core from aqueous corrosion in aerobic conditions and maintain its ferromagnetism. Due to the strong ferromagnetism of NZVI, a magnetism saturation value of 32.3 emu/g could be obtained with a high Zr content of 44.5 wt%, which could concurrently guarantee the quick magnetic separation for recycling and the high As(III) adsorption capacity. The Zr(OH)4 shell synthesized at room temperature possesses a weak crystalline and mesoporous structure. Abundant oxygen lattice defects with the uncoordinated Zr(IV) on the surface of Zr(OH)4 shell could be utilized for the As(III) removal via chemisorption. As a result, the NZVI@Zr(OH)4 performed a much higher capacity (380.0 mg-As·g−1 or 853.2 mg-As·g-Zr−1) than commercial Zr(OH)4 and other magnetic Zr-based materials, which was not affected by the pH variation and the co-existed environmental anions and natural organic matters. Therefore, NZVI@Zr(OH)4 is a promising material that can be applied and recycled to remove As(III) under diverse aqueous conditions.

Enhanced sorption of carbonyl groups by zirconium hydroxide modified with polydopamine for highly selective production of alcohols via MPV reduction under mild conditions

Enhanced sorption of catalysts to enrich and activate carbonyl substrates for highly selective production of the corresponding alcohols is an important means to boost the reaction rate. Based on the properties of dopamine polymerization under alkaline conditions, three mixtures of Zr and polydopamine with different structures were in situ synthesized by adjusting the feeding order of the raw materials. The three catalysts exhibited differences in physical adsorption capacity by N2 isothermal adsorption experiments, and the introduction of polydopamine strengthened the chemisorption of furfural by zirconium hydroxide as proved by ATR-IR. Zr-PDAE showed excellent MPV reduction ability for a variety of biomass-derived aldehydes and ketones, in which 93.9 % furfural conversion and 98.2 % furfural selectivity were achieved at 120 °C for 1 h. The modification of the selective adsorption of carbonyl substrate capacity is beneficial for the value-added conversion of biomass resources.

Hydrous zirconium oxide modified biochar for in situ remediation of arsenic contaminated agricultural soil

In-situ immobilization is a fast soil remediation method that can recover the value of As-contaminated land quickly. Hydrous zirconium oxide was reported for its efficient arsenic adsorption properties in wastewater treatment, but has not been reported in soil remediation with As contamination. Herein, hydrous zirconium oxide modified biochar (BC-Zr) was synthesized along with hydrous ferric oxide modified biochar (BC-Fe) and hydrous titanium oxide modified biochar (BC-Ti). After comparing their As(III)/As(V) adsorption performance under diverse conditions, BC-Zr showed superior As-immobilization potential in both simulated water and real soil leachate environment. To evaluate its performance in soil remediation, pot experiments were conducted in real As-contaminated agricultural soil using cowpea (Vigna unguiculata L.) as an indicator plant. Although all these modified BC could improve the growth of cowpea, the shoot biomass treated by BC-Zr increased by 115.8% than CK, while the As concentration in the stem and leaves decreased by 30.8% and 42.6%, respectively. Interestingly, BC-Zr promoted the root nodule system of cowpea in real As-contaminated soil while BC-Fe and BC-Ti failed. The observation of improved root nodule symbiotic system is significant for further development of soil remediation using in-situ remediation technology. This first successful trial of Zr-based soil amendment indicates the superior As-immobilization property of hydrous zirconium oxide in in-situ remediation of As-contaminated soil, implying the great potential applications of BC-Zr in soil remediation.

Synthesis of YSZ powders with controlled properties by the CDJP method

In this work, YSZ powders were synthesized by the controlled double-jet precipitation at constant pH values in the range from 3 to 8. It has been shown that weakly bound floccule-like particles with diffuse boundaries, obtained at pH 3, 7 and 8, strongly agglomerate during drying and form large particles of irregular shape. The dense spherical aggregates of zirconium hydroxide are formed only at CDJP at pH 4 and 5 due to the layer-by-layer buildup of primary particles on the surface of the aggregates. These dense aggregates capture less salt, do not undergo additional agglomeration during drying and retain a low size dispersion. YSZ powder obtained at pH 5 has a high bulk density and fluidity, as well as a narrower particle size distribution than conventional thermal spray powders. The use of this powder resulted in the formation of a uniform coating with high adhesion, uniform porosity and reduced roughness.

Synergistic effect of aluminum trihydrate and zirconium hydroxide nanoparticles on mechanical properties, flammability, and thermal degradation of polyester/jute fiber composite

Synergistic effect of aluminum trihydrate and zirconium hydroxide nanoparticles on mechanical properties, flammability, and thermal degradation of polyester/jute fiber composite

Superior Performance of Hydrous Zirconium Oxide Modified Biochar for Arsenic Immobilization in Contaminated Agricultural Soil

Superior Performance of Hydrous Zirconium Oxide Modified Biochar for Arsenic Immobilization in Contaminated Agricultural Soil

Surface functionalized poly(vinyl alcohol)–hydrous zirconium oxide composite beads for efficient and selective sequestration of phosphate from wastewater

Surface functionalized poly(vinyl alcohol)–hydrous zirconium oxide composite beads can efficient and selective sequestration of phosphate from real-wastewater, expanding the application scope of zirconium-based materials for phosphate sequestration.

Thermal-Vacuum Method for Obtaining Nanodispersed Zirconium Dioxide

An energy-efficient thermal-vacuum method for continuous production of nanodispersed powder of amorphous zirconium dioxide from zirconium hydroxide has been developed. This approach is based on a principle of creating an aerodynamic flow with an initial powder-like material in the cavity of the heating element of a thermal-vacuum installation. In this way, short-term contacts of particles of zirconium hydroxide with the inner surface of the heating element made in the form of the winding helical are created. As a result, the crushing of the particles is carried out due to the high thermal stresses in the particles contacted. This process is aggravated by the presence of residual moisture in the original powdery material. Transformations of the zirconium hydroxide in the process of thermal-vacuum treatment have been investigated. Amorphous dioxide has been obtained. The study of structural composition of the material in the initial state and processed in a thermal-vacuum installation was carried out using X-ray analysis and scanning microscopy. Experimental data on the structural-phase composition of the original material and data on the closest structural prototypes of crystalline-impurity compounds are presented. They are also given data on the volume of crystal cells and estimates of the molar concentration of the components. A mass spectrometric assessment of the elemental composition of the obtained zirconium dioxide is given. Thermal-vacuum method allows toobtain highly dispersed zirconium dioxide in its amorphous state directly from zirconium hydroxide without using liquid media and, moreover, in a short time – within 15...20 s.