Mesoporous Zirconium Phosphate Research Articles

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.

Preparation of Alkyl Levulinates from Xylose Over Modified Bifunctional Mesoporous Zirconium Phosphate Catalysts

Preparation of Alkyl Levulinates from Xylose Over Modified Bifunctional Mesoporous Zirconium Phosphate Catalysts

Amorphous Porous Chromium‐Zirconium Bimetallic Phosphate: Synthesis, Characterization and Application in Liquid Phase Oxidation of Hydrocarbons by Different Oxygen Sources

AbstractCr−Zr bimetallic phosphates catalysts were prepared by sol‐gel method and used in the oxidation of cyclohexane, ethylbenzene and cyclohexene, respectively. The catalysts were characterized by a variety of analytical techniques. The results show that chromium ions enter the framework of mesoporous zirconium phosphate, Cr−Zr phosphates catalysts with molar ratio of Cr: Zr=2 (CrZr2P) or Cr: Zr=1 (CrZrP) still retain the mesoporous structure and form composite metal phosphates. Two active centers‐ redox (Cr6+) and acidic sites in these bimetallic phosphates play a synergistic catalytic role in the oxidation of C−H bond. Catalytic activity is closely related to the amount of acid or acid strength, the C=O product selectivity depends on the amount and high dispersion of Cr6+ species. Acidic sites and redox sites are affected by different molar ratios of chromium/ zirconium. Among the Cr−Zr phosphates catalysts, CrZr2P and CrZrP catalysts show excellent activity, just because the formation of mesoporous structure leads to the uniform dispersion of acidic and redox sites.

Aqueous Phase Synthesis of 5-Hydroxymethylfurfural from Glucose over Large Pore Mesoporous Zirconium Phosphates: Effect of Calcination Temperature.

For a solid acid-catalyzed dehydration of biomass-derived carbohydrates into useful furan derivatives, a suitable porous solid acid catalyst having an optimum acidic density and its strength is required to avoid cascade reactions in biomass conversion processes. A large-pore mesoporous zirconium phosphate (m-ZrP) was prepared hydrothermally using P123 as a template in water solvent, which resulted in a higher pore diameter (>9 nm) having wormhole-like pore structures with balanced Lewis (L) to Brönsted (B) acid sites. The effects of calcination temperature (500–800 °C) on the textural, acidic/basic, and structural properties of the m-ZrP with its catalytic performance for glucose dehydration to 5-hydroxymethylfurfural (HMF) were investigated in a pure water media as a green and sustainable alternative solvent. The larger number of L and B acid sites and basic sites with their appropriate strengths were clearly related with a better catalytic performance in terms of glucose conversion and HMF yield. The strong L acid and basic sites in the m-ZrP efficiently promoted the glucose isomerization to fructose, which dehydrated exclusively on the weak B acid sites resulting in a maximum conversion of glucose (83.8%) and HMF yield (46.6%). The adjusted acidic and basic sites with large mesopore sizes make the m-ZrP yield a higher reaction rate (2.78 mmol gcat–1 h–1) and turnover frequency (11.68/h) for conversion of glucose to HMF, which showed higher catalytic activity than those of a small-pore m-ZrP and other mesoporous heterogeneous and homogeneous acid catalysts.

Facile Separation of 5-O-Galloylquinic Acid from Chinese Green Tea Extract using Mesoporous Zirconium Phosphate.

5-O-Galloylquinic acid from green tea and other plants is attracting increasing attention for its antioxidant and antileishmanial bioactivities. It is always isolated using a silica column, a Sephadex column and high-performance liquid chromatography (HPLC) methods, which are either laborious or instrument dependent. To develop a new method to easily separate 5-O-galloylquinic acid. Mesoporous zirconium phosphate (m-ZrP) was prepared to conveniently separate 5-O-galloylquinic acid from Chinese green tea extract, and the target compound was easily obtained by simple steps of adsorption, washing and desorption. The effects of the green tea extraction conditions, extract concentrations, and m-ZrP adsorption/desorption dynamics on the 5-O-galloylquinic acid separation were evaluated. 5-O-Galloylquinic acid that was separated from a 70% ethanol extract of green tea was of moderate HPLC purity (92%) and recovery (88%), and an increased non-specific binding of epigallocatechin gallate (EGCG) on m-ZrP was observed in the diluted tea extract. The times for maximal adsorption of 5-O-galloylquinic acid in 70% ethanol extract and maximal desorption of 5-O-galloylquinic acid in 0.4% phosphoric acid solution were confirmed as 7 h and 5 h, respectively. A facile method to separate 5-O-galloylquinic acid from Chinese green tea extract using m-ZrP was established. Copyright © 2016 John Wiley & Sons, Ltd.

Mesoporous metal(IV) phosphates as high performance acid catalysts for the synthesis of photochromic bis-naphthopyran via Claisen rearrangement

In this work, a facile and efficient one-step method for the synthesis of highly active mesoporous zirconium and tin(IV) phosphate that exhibit excellent catalytic activity for the synthesis of photochromic bis-naphthopyran via the Claisen rearrangement has been established. The synthesized catalysts were characterized by different textural and spectroscopic techniques such as XRD, FTIR spectra, SEM, TEM and N2 adsorption–desorption at −196 °C. The surface acidity of the prepared catalysts were determined by nonaqueous potentiometric titration with n-butylamine and FTIR of chemisorbed pyridine. XRD and N2 adsorption–desorption measurements showed that, the samples have some mesoporous structure. The surface acidity measurement showed that the samples contain mixture of Lewis and Bronsted acid sites. The results showed that zirconium phosphate samples have higher surface acidities than tin phosphate samples, and the samples with Zr:P ratio 1:3 and Sn:P ratio 1:2 showed the highest surface and Bronsted acidities. The prepared catalysts showed excellent catalytic activity for the synthesis of photochromic bis-naphthopyran via the Claisen rearrangement. High yield (~99 %) with 100 % selectivity of photochromic bis-naphthopyran was obtained in shorter reaction time at room temperature. These acid catalysts may solve the problematic low yield and purification difficulties of the photochromic chromenes reported previously.

Effective conversion of carbohydrates into biofuel precursor 5-hydroxymethylfurfural (HMF) over Cr-incorporated mesoporous zirconium phosphate

Catalytic conversion of carbohydrates into the platform chemical 5-hydroxymethylfurfural (HMF) is an important reaction in biomass conversion. In this work, the catalytic conversion of carbohydrates into HMF was studied over a heterogeneous chromium-exchanged zirconium phosphate catalyst (ZrP-Cr). Some important reaction parameters were studied with the aim to obtain high HMF yield from the dehydration of carbohydrates. Under optimal conditions, the dehydration of fructose afforded HMF in a high yield of 94.5%, and that was 43.2% when glucose was used as the feedstock. The recycling experiment indicated that the catalyst was stable, which indicated that catalyst can be reused by six times without significant loss of its catalytic activity.

Dehydration of fructose into 5-hydroxymethylfurfural by high stable ordered mesoporous zirconium phosphate

In this paper, a series of ordered mesoporous zirconium oxophosphate with different P/Zr molar ratios (M-ZrPO-x) were prepared via one-pot evaporation induced self-assembly strategy (EISA). The catalytic performance of M-ZrPO-x for the dehydration reaction of fructose to produce 5-hydroxymethylfurfural (5-HMF) was also studied. With high concentration of Brönsted and Lewis acid sites measured through NH3-TPD and pyridine-IR, M-ZrPO-0.75 performed high catalytic activity (up to 97.4%) and selectivity (79.6%) of 5-HMF under relatively mild conditions. Furthermore, M-ZrPO-0.75 performed excellent catalytic stability. Based on detailed analyses of XRD, SEM, TEM, BET and XRF, the structural, surface and textural properties of M-ZrPO-0.75 after reaction were investigated. Obtained results demonstrated that the mesostructure still retained even after twelve cycles, which may be ascribed to the “ordered” mesoporous properties and high thermal stability. In addition, a lower activation energy was obtained in this M-ZrPO catalytic system using dimethyl sulfoxide as solvent.

Fluoride removal from aqueous solutions using cerium loaded mesoporous zirconium phosphate

Adsorption of fluoride on cerium modified mesoporous zirconium phosphate.

Conversion of fructose, glucose and sucrose to 5-hydroxymethyl-2-furfural over mesoporous zirconium phosphate catalyst

5-Hydroxymethyl-2-furfural (HMF) is considered an important platform chemical among other intermediates derived from biomass. In this study, we have used mesoporous zirconium phosphate as a catalyst for the conversion of sugars into HMF. The catalyst was synthesized using a hydrothermal method and was characterized using powder XRD, FT-IR spectroscopy and FESEM. The as-prepared catalyst showed porous structure and a very high surface area. Mesoporous zirconium phosphate exhibited excellent catalytic activity for the formation of HMF, from fructose, glucose and sucrose. The effect of various factors such as reaction time, temperature and reaction systems on formation of HMF has been investigated.

Effect of Synthesis Conditions on Formation of Thermally Stable Mesoporous Zirconium Phosphate

We have studied the effect of synthesis conditions on formation of thermally stable mesoporous zirconium phosphate. We have used X-ray diffraction, temperature-programmed desorption of ammonia, IR spectroscopy, NMR, and DTA to establish that formation of hexagonally ordered materials which are stable during detemplating is possible only when using cationic and nonionic surfactants, a temperature of 20 °C, and post-synthesis treatment with a solution of orthophosphoric acid. We have established that, depending on the ordering, there is a change in both the adsorption characteristics of the zirconium phosphate as well as the concentration of acid sites and their strength distribution.

Investigation into the Antibacterial Activity of Mesoporous Zirconium Phosphate against Beer-Spoilage Organisms

The aim of this study was to examine the antimicrobial effect of mesoporous zirconium phosphate (M-Zrp), which is an inorganic nano material with apertures in the range of 2–50 nm. It could be used as an antibacterial agent against beer-spoilage organisms. The template synthesis of M-Zrp is an important method of producing M-Zrp. Biological templates have many advantages, including less toxicity, and are more friendly to the environment. M-Zrps were produced by fresh yeast through biomimetic synthesis. The antibacterial activity of M-Zrp prepared from the yeast biotemplate was investigated using the inhibition zone test. The impacts of preparation process, treatment time, bacteria concentration, and sample structure on the antibacterial property were examined. The results showed that M-Zrp showed bacteriostatic activity against Saccharomyces diastaticus, Candida albicans, Pediococcus damnosus, and Escherichia coli but showed no effect on Lactobacillus brevis or Pectinatus cerevisiiphilus. The mean diameters of the inhibition zones were 11.67, 12.37, 8.64, and 10.36 mm. The antibacterial activity increased as the concentration of M-Zrp increased and the particle size decreased. Within a certain range, the effect was enhanced with the prolongation of the treatment time. Using the spectroscopic method, the minimal inhibitory concentrations were determined to be 10 mg/L for S. diastaticus, C. albicans, and E. coli, and 25 mg/L for P. damnosus. The morphology of S. diastaticus before and after M-Zrp treatment was observed under a polarization microscope. The presence of M-Zrp first damaged the membrane of the bacterium and subsequently integrated into the cell wall and interacted with the internal components, resulting in the leakage of intracellular contents and, eventually, the death of the bacteria. Our findings suggested that M-Zrp exhibited an effective antimicrobial effect and the potential as an antibacterial coating or additive for the food and beverage industry.

High performance mesoporous zirconium phosphate for dehydration of xylose to furfural in aqueous-phase

The conversion of sugars to chemicals in aqueous-phase is especially important for the utilization of biomass. In current work, zirconium phosphate obtained by hydrothermal methods using organic amines as templates has been examined as a solid catalyst for the dehydration reaction of xylose to furfural in aqueous-phase. The use of dodecylamine and hexadecylamine in the synthesis process results in mesoporous zirconium phosphate with uniform pore width of ∼2 nm and in morphology of nanoaggregates, which is characterized by powder X-ray diffraction, N2 isothermal sorption, NH3 temperature-programmed desorption, FT-IR, and 31P MAS NMR spectroscopy. When used as a catalyst for xylose dehydration to furfural in aqueous-phase, the mesoporous zirconium phosphate presents excellent catalytic performance with high conversions up to 96% and high furfural yields up to 52% in a short time of reaction. Moreover, the catalyst is easily regenerated by thermal treatment in air and shows quite stable activity. The open structure with numerous active sites of the Brønsted/Lewis acid sites is responsible for the high catalytic efficiency of mesoporous zirconium phosphate.

Room temperature Baeyer–Villiger oxidation using molecular oxygen over mesoporous zirconium phosphate

Lactones have found wide applications as key molecules for the synthesis of important bioactive compounds, natural products and polymers; and represent a valuable family of synthons for various organic transformations. A series of lactones or esters are synthesized from their corresponding ketones employing Baeyer–Villiger (BV) oxidation at room temperature using mesoporous zirconium phosphate (m-ZrP) as a solid acid catalyst, molecular oxygen (O2)/benzaldehyde as an oxidizing agent, in a solvent free reaction medium. The oxidation reaction is studied in detail by varying the reaction parameters like molar ratio of the reactants, reaction temperature, time and catalyst loading. The m-ZrP showed high catalytic activity for the BV oxidation of cyclohexanone as well as other ketones in the presence of reduced amount of benzaldehyde with 100% selectivity for the corresponding lactones/esters. The protocol is suitable even for bulkier cyclic ketones like adamantanone. The m-ZrP catalyst showed excellent reusability.

Allylic and Benzylic Oxidation over CrIII-Incorporated Mesoporous Zirconium Phosphate with 100 % Selectivity

Elite selection: The selective oxidation of allylic and benzylic compounds to the corresponding carbonyl compounds (enones), using H2O2 as oxidant and methanol as solvent over chromiumincorporated mesoporous zirconium phosphate, is evaluated.

Microwave assisted synthesis of fine chemicals in solvent-free conditions over mesoporous zirconium phosphate

Synthesis of various industrially important fine chemicals under microwave irradiation (MWI) in solvent-free conditions over mesoporous zirconium phosphate (m-ZrP) is reported. m-ZrP is synthesized by MWI in basic medium using a precursor solution of zirconium carbonate complex as zirconium source and CTAB as a pore-directing agent. MWI time and MWI power were found to have significant influence on the textural properties of synthesized m-ZrP. Microscopic analyses of the synthesized m-ZrP indicate the presence of worm like pores with spherical morphology. DRIFT analysis of pyridine adsorbed m-ZrP and NH3-TPD measurements indicate the presence of appreciable amount of Brönsted acid sites. Synthesized m-ZrP exhibits high catalytic activity towards Claisen–Schmidt condensation reaction in solvent-free conditions under microwave irradiation. The m-ZrP showed high activity towards other acid catalyzed reactions such as Friedel–Craft benzylation, Pechmann condensation and carbonyl group protection reaction, and also for the synthesis of benzo-xanthenes in solvent-free conditions under MWI. The catalytic activity of m-ZrP is substantially higher than that of conventional layered ZrP. The synthesized catalysts are re-usable for at least five times after regeneration, without losing their catalytic activity significantly.

Mesoporous zirconium phosphate: An efficient catalyst for the synthesis of coumarin derivatives through Pechmann condensation reaction

Mesoporous zirconium phosphate (m-ZrP) is used as a solid acid catalyst for the synthesis of coumarins via Pechmann condensation reaction and gave high catalytic activity for the condensation of phenols and ethyl acetoacetate in both conventional heating as well as microwave assisted method. The condensation reaction is studied in detail by varying the reaction parameters like effect of solvent, molar ratio of the reactants, temperature, and catalyst loading. Among the substituted phenols, m-amino phenol is more reactive and 100% yield is obtained in very short time at low temperature due to the presence of ring activating amine group in meta position. The m-ZrP is also active even for simple phenol and 57% yield of 4-methyl coumarin is obtained in conventional heating method. Microwave assisted synthetic method is found to be advantageous over conventional heating for the synthesis of coumarins, as it provides improved yield in very less time.

Mesoporous zirconium phosphate catalyzed reactions: Synthesis of industrially important chemicals in solvent-free conditions

Mesoporous zirconium phosphate (m-ZrP) having high specific surface area and narrow pore size distributions is synthesized in basic medium using zirconium carbonate as source of zirconium. The concentration of phosphate in precursor solutions, as well as the calcination temperature, is found to influence the textural properties and acidity of synthesized m-ZrP significantly. Microscopic analysis indicates the presence of worm like pores with spherical morphology. The porous structure has remarkable thermal stability (up to 800 °C). DRIFT and NH 3-TPD analysis suggest the presence of reasonable amount of Lewis and Brönsted acid sites. High catalytic activity of synthesized m-ZrP is observed towards Friedel–Craft (F.C.) benzylation reaction. The effect of acid strength of catalyst, reaction time, temperature and amount of catalyst towards Friedel–Craft benzylation reaction are also studied. The m-ZrP is highly active towards other acid catalyzed reactions in solvent-free conditions. The catalytic activity of m-ZrP is much higher than that of conventional layered ZrP. The catalysts were separated easily from reaction mixture, regenerated after a simple activation step and reused at least six times without significant loss in catalytic activity.

Operando XAS and Raman study on the structure of a supported vanadium oxide catalyst during the oxidation of H 2S to sulphur

The modification of crystalline phases of a vanadium oxide supported on mesoporous zirconium phosphate during the partial oxidation of H 2S to sulphur has been studied by using an operando Raman-GC approach and XAS in reaction conditions. The catalyst, mainly presenting crystalline V 2O 5, is transformed during the oxidation of H 2S at 200 °C, presenting crystals of V 4O 9, which is identified by the presence of a band at ca. 900 cm −1 in the Raman spectra (using a 785 nm line of an Argon ion laser) and by the presence of a pre-edge at 5469.8 eV (and a main-edge at 5482.2 eV) in XANES spectra. At the same time, it is observed a high conversion of H 2S to sulphur (the main reaction product) and SO 2 (as minority). Both activity and selectivity depend on the time on stream. In this way, the selectivity to SO 2 decreases from ca. 5 to 1% with the time on stream. This change could be explained on the basis of the nature of V-species: the initial presence of V 5+–O–V 5+ pairs and the appearance of V 5+–O–V 4+ pairs at high time on stream.

Mesoporous zirconium phosphate from yeast biotemplate

Mesoporous zirconium phosphate has attracted increasing interest due to its extraordinary functionalities. In particular, great progress has been made in the synthesis of mesoporous zirconium phosphate using traditional approaches. However, synthesis of mesoporous zirconium phosphate using yeast as biotemplate has not been well studied so far. Here, we show that zirconium phosphate with a mesoporous structure has been synthesized under ambient conditions using yeast as biotemplate. The derived samples were examined by X-ray diffraction (XRD), energy-dispersive X-ray analysis (EDX), transmission electron microscopy (TEM), thermogravimetry/differential thermal analysis (TG/DTA), fourier transform infrared spectroscopy (FTIR), and N 2 adsorption–desorption isotherms. A biotemplated mesoporous zirconium phosphate, possessing a specific surface area (Brunauer–Emmett–Teller, BET) of 217.64 m 2 g −1, a narrow pore distribution centered at 2.7 nm, and pore volume of 0.24 cm 3 g −1, was obtained. We discover that amide carboxyl groups of yeast play an important role in the chemical interaction between protein molecules and zirconium phosphate nanoparticles. Interestingly, an air electrode fabricated using mesoporous zirconium phosphate exhibits remarkable electrocatalytic activity for oxygen reduction reaction (ORR), compared to that of the electrolytic manganese dioxide (EMD) air electrode employed commercially, which has important applications in fuel cell technologies.