Zr Source Research Articles

Effect of a Zr source addition on the microstructure of Al-SiC composites elaborated by the Laser Powder Bed Fusion (L-PBF) process

The present work focuses on the effect of the addition of a zirconium source on the microstructure of Al-SiC composites produced by Laser Powder Bed Fusion (L-PBF). More specifically, the aim is to address the issue of the SiC decomposition into the water-soluble aluminum carbide Al4C3 in Al-SiC composites produced by L-PBF, with the objective of limiting its formation by adding another element to the system. To this end, AlSi7Mg0.6-SiC-ZrO2 composite powders are successfully prepared and printed in a standard L-PBF equipment. The resulting parts are then thoroughly characterized, in order to understand the physico-chemical mechanisms involved during the L-PBF process. The results show a decrease in the Al4C3 amount by ZrC formation. Another important result is that bulk composites exhibit a fully equiaxed microstructure attributed to the τ1 (Al,Si)3Zr ternary phase, with all the characteristics of a good nucleating agent for aluminum phase. To support these microstructure experimental results, a first version of a quaternary Al-Zr-Si-C thermodynamic database was developed using the Calphad method. These calculations enable to establish a solidification path providing information on the phases that may form after heat treatment of L-PBF materials.

A new way to tune photocatalytic activity, surface morphology, and structural/optical parameters of ZrO2 thin films using different Zr sources along with annealing temperature and film thickness

A new way to tune photocatalytic activity, surface morphology, and structural/optical parameters of ZrO2 thin films using different Zr sources along with annealing temperature and film thickness

Remote vapor-phase dual alkali halide salts assisted quasi-van der Waals epitaxy of m-phase ZrO2 thin films with high dielectric constant and stable flexible properties

High-κ dielectric constant and wideband gap of ZrO2 material render it as an excellent candidate for transistor gate dielectric layers. However, current reported synthesis techniques suffer the problems of high precursor volatilization rate, ultrasmall grains with low dielectric constant, and high leakage current, which largely impede its application in electronic devices. Here, the quasi-van der Waals epitaxy growth of compact m-phase ZrO2 thin films has been developed, in which the stable supply of Zr source is realized by the tuned sublimation of ZrC powder with remote vapor-phase dual halide salts assistant. The formation of m-phase ZrO2 is due to the lower Gibbs free energy, in which the crystal nucleates at the etched hole edges of mica substrate, thus forming hexagonal shape polycrystal grains and merging as the continuous thin films. The microstructures and Raman spectrum characterization reveal the two dominated growth orientations and good crystal qualities, which indicate the uniform dielectric constant. The excellent growth reproducibility could be easily adapted to thin metal substrates, such as tungsten, molybdenum, and stainless steel, where the adhesion strength is strong because of the higher density of interfacial chemical bonding. Meanwhile, the metal–insulator–metal flexible capacitors show the high dielectric constant of 23–26 and low leakage current density of 10−4 A/cm2 at large voltage and only exhibit the decreased capacitance density of 7% after several hundred bending cycles. Our work paves a way to achieve the high-quality dielectric thin films on various substrates by the unique chemical vapor deposition design strategy.

Al-Rich Titanites from Mont Blanc Alpine Fissures: Evidence of Ti-Nb-Y-REE Mobility during Water–Rock Interactions

Titanites can be excellent markers of element transfer in medium-temperature retrograde metamorphism. Euhedral titanites from several alpine fissures from Mont Blanc, particularly those of Périades and Courtes, crystallised at the end of the main quartz stage and are synchronous with the formation of green biotites and albite before chlorite formation. Micro-XRF, SEM, electron probe, and LA-ICP-MS analyses show that these titanites have a wide range of Al2O3 content from 1 to 8%, are dominated by -OH versus F, and have a wide range of Nb (up to 4500 ppm), Y (up to 3000 ppm), Zr (up to 1800 ppm), and Sn (up to 1400 ppm) concentrations. The allanite from the granite, partly destabilised into epidote, is the most likely source of Nb, Y, Zr, Sn, and REE. Titanites are enriched in HREE and show variations in LREE depending on the studied sites. Like quartz, they formed at around 400 ± 20 °C, which is compatible with the formation of green biotites after the destabilisation of granite Fe-Mg silicates. This early stage of fluid circulation, synchronous with the Mont Blanc massif uplift, is therefore marked by the titanite formation at the transition between the biotite and chlorite stability fields.

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.

Boosting the electrochemical performance of LiCoO2 by triple-phase interface via “island-bridge” shaped surface coating

Surface coating as an effective strategy has been extensively utilized to enhance the surface/interface stability of cathode for lithium-ion batteries. As widely recognized, the electrochemical performance of coated cathode is greatly dependent on the properties of coating layer. Rational design on the structure and composition of coating layer becomes crucial. Here, a unique “island-bridge” shaped Zr-based coating layer has been constructed through a facile synthetic protocol. This coating layer composes of several high-crystalline ZrO2 nanoparticles and a thin low-crystalline zirconium hydroxide layer that connects these nanoparticles, forming a typical “island-bridge” structure. The successful formation of such a unique coating layer was demonstrated to be related to the usage amount of Zr source and the calcined temperature. The novel “island-bridge” coating has been successfully applied to modify the surface of LiCoO2, showing excellent capability on improving the electrochemical performance. The unique “island-bridge” structure coating induces the formation of a triple-phase interface, namely island-cathode-bridge interface. Theoretical calculation suggests that such an island-cathode-bridge triple-phase interface can effectively reduce the Li+ diffusion energy, leading to favorable Li+ transportation kinetics and suppressed cathode-electrolyte interface evolution. Furthermore, this “island-bridge” layer can well prevent direct contact between LiCoO2 and electrolyte, enhancing the surface/interface stability, resulting in improved cyclic performance. This work provides new insights into the rational design of surface coating for high-energy density cathodes.

Effect Temperature for improving the Li-ion conductivity of Li7La3Zr2O12

This study investigates the dissociation behavior of water-soluble salts of Li and La and the unique behavior of Zr sources, resulting in the generation of Li+, La3+, and Zr4+ ions in aqueous solutions. The specific conductivity of calcined SG1 and SG2 displays temperature-dependent variations, with SG1 consistently exhibiting higher conductivity (2.08 x 10-4 S/cm) across the temperature range. The closed-packed structure facilitates the controllable mass transfer of lithium, enhancing ionic conductivity. The constructed LiFePO4/LLZO/AC device using these electrolytes demonstrates an impressive energy density of 1.95 Wh/kg and a power density of 144.92 W/kg, showcasing an excellent solid electrode-electrolyte interphase. Over 10,000 cycles, cyclic stability, with an average performance of 86%, underscores the potential of LLZO as a solid electrolyte for advanced energy storage devices. The sol-gel synthesis and densification strategy is a simple and effective method for obtaining lithium-rich LLZO electrolytes. The enhanced ionic conductivity and electrochemical performance of the solid-state device emphasize the practical viability of this approach, contributing to the sustainable development of advanced energy storage technologies.

Insights into the Spray Synthesis of UiO-66 and UiO-66-NH2 Metal–Organic Frameworks: Effect of Zirconium Precursors and Process Parameters

UiO-66, a zirconium-based metal–organic framework, was synthesized using a one-step spray synthesis method to investigate the effects of preheating the precursor solution and Zr sources on crystallinity. Using ZrCl4 with water as a modulator requires preheating at 80 °C for 120 min or 120 °C for 30 min for the spray synthesis of UiO-66 to form secondary building units (SBUs). By contrast, the use of Zr(OnPr)4 with acetic acid (AcOH) as a modulator allowed the spray synthesis of UiO-66 and UiO-66-NH2 without preheating because of the rapid formation of SBUs with AcOH. The spray-synthesized UiO-66 using Zr(OnPr)4 exhibited a BET surface area of 1258 m2/g and a CO2 adsorption capacity of 3.43 mmol/g at 273 K and 1 bar, while UiO-66-NH2 exhibited a BET surface area of 1263 m2/g and a CO2 adsorption capacity of 6.11 mmol/g under the same conditions.

Prograde zircon growth in migmatites

AbstractEmpirical studies of zircon in migmatites document features compatible with growth during heating at suprasolidus conditions. However, numerical modelling of zircon behaviour suggests that suprasolidus zircon is expected to grow only during cooling and melt crystallization. Here, phase equilibrium modelling coupled with mineral–melt Zr partitioning is used in an attempt to reconcile the observations from migmatites with the predictions of previous numerical models of zircon behaviour in anatectic systems. In general, an equilibrium‐based model that includes Zr partitioning does not allow prograde suprasolidus zircon growth. However, melting of metapelites at temperatures just above the wet solidus may allow limited zircon growth because of the low solubility of zircon in melt coupled with a source of Zr from minor garnet and ilmenite breakdown. Preservation of this zircon requires entrapment in growing peritectic minerals during subsequent heating and further melting. Heating above muscovite exhaustion in metapelites is unlikely to grow zircon because of the progressive increase in zircon solubility as well as an increasing compatibility of Zr in the residual mineral assemblage. The modelled compatibility of Zr in the residue of a metabasite decreases during heating, but an increase in zircon solubility in melt counteracts this; prograde suprasolidus zircon growth in metabasites is unlikely. Infiltration of Zr‐rich melt into a migmatite during open‐system anatexis provides an additional potential mechanism for prograde suprasolidus zircon growth during high‐temperature metamorphism.

Direct ethyl acetate synthesis from ethanol over amorphous-, monoclinic-, tetragonal ZrO2 supported copper catalysts prepared from the same zirconium source

Direct ethyl acetate synthesis from ethanol was examined by supported Cu catalysts on various kinds of acid-base metal oxides, available ZrO2-based oxides, and homemade amorphous-, monoclinic- and tetragonal zirconia prepared from the same Zr source. XRD, XAFS, TG-DTA characterization and surface area measurement were performed. Effects of crystalline phase of ZrO2 support on selective ethyl acetate production was discussed based on the yields and products ratio (ethyl acetate to sum of C4-alcohols and aldehydes). Based on catalytic performance by 29 kinds of homemade catalysts, amorphous-type ZrO2 was found to be essentially the most suitable ZrO2 phase for the selective ethyl acetate formation in cases without any surface modifications. The acid site on the surface of monoclinic-type ZrO2 catalysts possibly promoted unfavorable acetaldehyde condensation reaction, but addition of Na+ for poisoning could increase selectivity of ethyl acetate formation. Coordination environment of Cu species for fresh and spent catalysts were discussed.

Recovery of Uranium, Thorium, and Other Rare Metals from Eudialyte Concentrate by a Binary Extractant Based on 1,5-bis[2-(hydroxyethoxyphosphoryl)-4-ethylphenoxy]-3-oxapentane and Methyl Trioctylammonium Nitrate

Eudialyte-group minerals are of scientific interest as important concentrators of rare elements (mainly Zr and REE) in agpaitic alkaline rocks and a potential source of REE, Zr, Hf, Nb, and Ta for industrial use. Extraction of uranium(VI), thorium(IV), zirconium(IV), hafnium(IV), titanium(IV), and scandium(III) by a binary extractant based on 1,5-bis[2-(hydroxyethoxyphosphoryl)-4-ethylphenoxy]-3-oxapentane and methyl trioctylammonium nitrate from eudialyte breakdown solutions is studied. Extraction isotherms were obtained and exhaustive extraction was investigated. It is shown that uranium, thorium, hafnium, zirconium, scandium, and titanium are almost completely recovered in two-stage extraction by a mixture of 1,5-bis[2-(hydroxyethoxyphosphoryl)-4-ethylphenoxy]-3-oxapentane and methyltrioctylammonium nitrate in 1,2-dichloroethane. Quantitative characteristics were compared for uranium(VI), thorium(IV), zirconium(IV), hafnium(IV), titanium(IV), and scandium(III). It was shown that the extraction efficiency of the metals by the binary extractant based on 1,5-bis[2-(hydroxyethoxyphosphoryl)-4-ethylphenoxy]-3-oxapentane and methyltrioctylammonium nitrate in 1,2-dichloroethane is much higher in comparison with the commercially available tributyl phosphate.

Exploring the origin of ZrO2 phase in Na3Zr2Si2PO12 ceramic electrolyte

The development of solid-state batteries based on NASICON-type Na3Zr2Si2PO12 (NZSP) ceramic electrolytes is critically hampered by their unfavorable room temperature ionic conductivity. Moreover, the inadvertent appearance of ionic insulator ZrO2 phase within NZSP matrix constantly bothers these relevant researches. In this work, via utilizing different kinds of starting materials, it is found that the kinds of Zr source and sintering temperature can regularly affect the relative content of ZrO2 in the NASICON matrix. More significantly, it reveals that there is no direct correlation between the ZrO2 content and the room temperature ionic conductivity of NZSP. Moreover, NZSP obtained at 1150 °C via solid-state reaction with Na2CO3, ZrO2, SiO2, and NH4H2PO4 as starting materials can achieve a room temperature conductivity of 9.1 × 10−4 S cm−1, which is a relatively high value. The work here offers a thorough understanding of the origin of ZrO2 phase in NASICON as well as guidance for the mass production of NASICON-type ceramic electrolytes via conventional solid-sate reaction.

Synthesis and thermal performance of polymer precursor for ZrC ceramic

A novel ZrC preceramic precursor (PZC) was compounded via liquid phase chemical reaction without any organic solvent choosing ZrOCl2·8H2O and polyvinyl alcohol as Zr source and C source, respectively. The composition and structure of ZrC precursor were analysed through XRD, FT-IR, XPS and SEM. The results showed both Zr-O-C bonds and Zr-O bonds existed in the precursor. The results observed by SEM showed that many irregular particles were generated, whose particle sizes were mainly in the range of 0.2–3 μm. In addition, particle aggregation can be easily observed. Besides, the thermal property and pyrolysis process of PZC were studied. In accordance with XRD, the initial temperature of the earliest detection of ZrC in pyrolysis products of PZC was 1300 °C. Monoclinic ZrO2 and tetragonal ZrO2 can be observed at this temperature as well. Ulteriorly, when the pyrolysis temperature was risen up to 1500 °C, only ZrC ceramic can be found.

Effect of precursor solution parameters on the formation of yttria stabilized zirconia coatings on yttria stabilized bismuth oxide substrates

A useful intermediate temperature solid oxide fuel cell design could be the utilization of yttria doped bismuth oxide (YDB) ceramics as electrolyte supports, which would also enable the use of high-performing nanocomposite thin film electrodes. However, to prevent the reduction of YDB down to metal upon contact with hydrogen, a thin, chemically stable ionic conductor ceramic coating must be applied onto the fuel side of the anode. In this work, we aim to determine the optimum parameters to fabricate dense and crack-free yttria-stabilized zirconia (YSZ) doped zirconia coatings onto sintered yttria doped bismuth oxide (YDB) ceramics by a facile, cost effective polymeric precursor method, for the first time in the literature. We have found that the most commonly used Zr source, zirconium oxychloride octahydrate, i) reacts with the YDB substrate to form bismuth yttrium oxychloride and ii) results in crack formation due to reduced extent of polymerization unless the solution is fed with nitric acid. Meanwhile, the use of zirconium oxynitrate hydrate forms dense, crack free thin films. Both thin films had low conductivities, in the range of 10−6 S/cm at 600 °C, likely, due to the lack of crystallization in their as-deposited state.

Distribution, contamination status and source of trace elements in the soil around brick kilns

This study reports the distribution, contamination level, and possible sources of 54 metal (oid)s in the soils found around brick kilns in south-western Bangladesh. In total, 40 soil samples were collected from the vicinity of five brick kilns in four directions at 250 m intervals. This study reveals that the mean respective concentrations of caesium (Cs), beryllium (Be), lead (Pb), cerium (Ce), praseodymium (Pr), neodymium (Nd), samarium (Sm), europium (Eu), dysprosium (Dy), holmium (Ho), terbium (Tb), erbium (Er), thulium (Tm), ytterbium (Yb), thorium (Th), germanium (Ge), yttrium (Y), zirconium (Zr), niobium (Nb), silver (Ag), hafnium (Hf), tantalum (Ta), and tungsten (W), were 7.83, 3.19, 22.93, 85.93, 9.61, 36.86, 7.30, 1.23, 5.76, 1.13, 0.99, 3.14, 0.45, 2.91, 17.72, 3.04, 30.07, 185.13, 13.99, 0.30, 5.34, 1.26, and 2.61 μg g−1. Furthermore, those amounts exceeded their respective shale values. The pollution evaluation indices indicated a moderate level of contamination by Cs, Pb, Th, Ag, Hf, Ta, W, and lanthanides but excluding lanthanum (La) and lutetium (Lu). The pollution load index revealed pollution at two brickfields. Multivariate statistics reported that coal combustion in the brick kilns is the primary source of lanthanides, actinides, Y, Zr, and Hf in the soil, while other elements derived mostly from natural sources. A portion originated from coal combustion in brick kilns and agricultural activities. Changes in metal (oid)s concentrations were non-linear with the distance between the kilns and sampling points. Consequently, further studies are required and should consider meteorological factors and severity of human impact in the study area.

Influence of Water in the Synthesis of the Zirconium-Based Metal-Organic Framework UiO-66: Isolation and Reactivity of [ZrCl(OH)2(DMF)2]Cl.

We recently discovered that aging a solution of zirconium(IV) tetrachloride (ZrCl4) in N,N-dimethylformamide (DMF) in the presence of water, followed by the addition of a terephthalic acid linker, reduces the crystallite size of the metal-organic framework UiO-66 (Chem. Commun. 2016, 52, 6411-6414). In an effort to shed light on the nature of the aging effect and on its relationship with the crystallite size of UiO-66, we report here the isolation and structural characterization of a microcrystalline zirconium-based compound of the formula [ZrCl(OH)2(DMF)2]Cl, which is formed during the aging process. The Zr(IV) ions are coordinated by hydroxide, DMF, and chloride to produce a one-dimensional polymer. Thanks to the presence of two -OH groups per zirconium atom, [ZrCl(OH)2(DMF)2]Cl is a suitable precursor for the synthesis of UiO-66 in dry DMF, affording a product having a smaller crystallite size than that obtained from a reaction mixture having the same chemical composition but using ZrCl4 as the Zr(IV) source. By starting from ZrCl4 and generating [ZrCl(OH)2(DMF)2]Cl in situ in solution through aging, we obtained smaller crystallites as the aging time increased, proving that [ZrCl(OH)2(DMF)2]Cl plays a role in the aging process. The possible role of [ZrCl(OH)2(DMF)2]Cl in the crystallization mechanism of UiO-66 is also discussed, with emphasis on its relationship with the amount of water in the reaction mixture.

Valorization of Rare Earth Elements from a Steenstrupine Concentrate Via a Combined Hydrometallurgical and Pyrometallurgical Method

Due to their unique characteristics, Lanthanides series (15 elements) together with scandium and yttrium are used as critical metals in numerous applications such as energy sources, catalysts, hybrid cars, medical technology, and military industry. The significance of rare earth elements has been continuously increasing because the global demand for producing high-tech devices is continuously rising. The recovery of rare earth oxide from concentrate based on eudialyte and steenstrupine was performed using a hydrometallurgical and pyrometallurgical method. Eudialyte and steenstrupine are a complex Na-Ca-zirconosilicate mineral containing rare earth elements (REEs), Zr, Hf and Nb, thus serving as a potential source of Zr. Because of the presence of silica in eudialyte, the main challenge in its processing is avoiding silica gel formation, which is an unfilterable solid residue. The influence of leaching temperature, time and solid–liquid ratio on leaching efficiency was studied in laboratory conditions. A new research strategy was developed in order to recover rare earth elements using hydrochloric acid, avoiding silica gel formation.

High-Ni cathode material improved with Zr for stable cycling of Li-ion rechargeable batteries.

The Zr solvent solution method, which allows primary and secondary particles of LiNi0.90Co0.05Mn0.05O2 (NCM) to be uniformly doped with Zr and simultaneously to be coated with an Li2ZrO3 layer, is introduced in this paper. For Zr doped NCM, which is formed using the Zr solvent solution method (L-NCM), most of the pinholes inside the precursor disappear owing to the diffusion of the Zr dopant solution compared with Zr-doped NCM, which is formed using the dry solid mixing method from the (Ni0.90Co0.05Mn0.05)(OH)2 precursor and the Zr source (S-NCM), and Li2ZrO3 is formed at the pinhole sites. The mechanical strength of the powder is enhanced by the removal of the pinholes by the formation of Li2ZrO3 resulting from diffusion of the solvent during the mixing process, which provides protection from cracking. The coating layer functions as a protective layer during the washing process for removing the residual Li. The electrochemical performance is improved by the synergetic effects of suitable coatings and the enhanced structural stability. The capacity-retentions for 2032 coin cells are 86.08%, 92.12%, and 96.85% at the 50th cycle for pristine NCM, S-NCM, and L-NCM, respectively. The superiority of the liquid mixing method is demonstrated for 18 650 full cells. In the 300th cycle in the voltage range of 2.8–4.35 V, the capacity-retentions for S-NCM and L-NCM are 77.72% and 81.95%, respectively.

Геохимия марганценосных отложений палеовулканогенных комплексов Южного Урала

Research subject . This article is devoted to the geochemistry of manganese deposits referred to the Devonian paleovolcanic complexes of the Magnitogorsk belt in the Southern Urals. Materials and methods . A series of studies was conducted using materials collected from the Kyzyl-Tash, Kazgan-Tash, Kozhayevskoye, Bikkulovskoye and Southern Fayzuinskoye deposits. The content of main elements and rare-earth elements was determined using the X-ray spectral fluorescent and ICP-MS methods, respectively. Results. It is shown that the values of indicator lithochemical modules in the manganese rocks under study are comparable to those in the modern metal- and ore-bearing sediments. The manganese rocks are characterized by low concentrations of rare-earth elements, as well as by a negative Ce anomaly (Ce/Ce* = 0.20-0.85) in their spectrum and an insignificant prevalence of heavy lanthanides over light ones. In terms of the REE spectrum configuration, the rocks under study are close to modern ferromanganese deposits of a hydrothermal genesis. Conclusion. The most probable source of Li, Be, Sc, Cr, Rb, Zr, Nb, Hf and Th in the manganese deposits was the detrital material of background sediments. Co, Ni, Ge, As, Mo and Sb, which concentration in the studied rocks is higher compared to that in the detrital component, are most likely to have been produced by hydrothermal solutions. Other rare elements could have been brought into the sediments through different routes. In general, according to the distribution of main, rare and rare-earth elements, the manganese rocks in the Southern Urals are comparable to the deposits of low-temperature hydrothermal sources, which developed within the arc system of the modern ocean. Our findings agree well with the concept of the hydrothermal-sedimentary origin of manganese deposits in the Southern Urals, thus supplementing this hypothesis by the data obtained using independent sources.

Hydration of α‐Pinene over SO42−/Zr‐MCM‐41 in Supercritical Carbon Dioxide

AbstractThe hydration of α‐Pinene to α‐Terpineol was studied using SO42−/Zr‐MCM‐41 mesoporous molecular sieves as catalysts in supercritical carbon dioxide (scCO2). The reaction results showed SO42−/Zr‐MCM‐41 was of better selectivity to the α‐Terpineol in scCO2 than in conventional conditions, and was of the same catalytic activities in scCO2 and in conventional conditions. The effect of some factors on the catalytic activities and the regenerable performance of SO42−/Zr‐MCM‐41, such as different Zr source, the method of introducing SO42−, the concentration of SO42−, calcination temperature and calcination time, were studied. These results showed the cooperation of Zr and SO42− was the main reason that SO42−/Zr‐MCM‐41 was of excellent catalytic activity, and Zr(SO4)2, as the Zr source, was active for the regenerable performance of SO42−/Zr‐MCM‐41.