Phosphomolybdic Acid Research Articles

Phosphomolybdic acid enhancing hexavalent chromium bio-reduction in long-term operation: Optimal dosage and mechanism analysis

The bio-reduction of Cr(VI) is regarded as a feasible and safe strategy to treat Cr pollution. The optimal concentration of phosphomolybdic acid (PMo12) for Cr(VI) reduction and the catalytic mechanism of electron behavior (electron production, electron transport and electron consumption) were revealed in denitrifying biofilm systems. The results showed that 0.1 mM PMo12 could achieve 92.5 % removal efficiency of 90 mg/L Cr(VI), which was 47.7 % higher than that of PMo12-free system, and improve the extracellular fixation capacity of Cr(III). The activity of peroxidase (POD) was significantly promoted by PMo12 to repair oxidative stress damage caused by Cr(VI) reduction. Additionally, analysis of electron behavior demonstrated that PMo12 could enhance key indicators of electron production, transport and consumption. This led to rapid activation of the electron pathway inhibited by Cr(VI), enabling simultaneous efficient nitrogen removal and Cr(VI) reduction in the biofilm system. This discovery will provide an efficient technique for Cr-containing wastewater treatment.

Heteropolyacid supported on ionic liquid decorated hierarchical faujasite zeolite as an efficient catalyst for glycerol acetalization to solketal

To handle huge amount of glycerol produced in biodiesel industry, glycerol is transformed to value-added products. In this regard, glycerol acetalization to solketal is industrially attractive. As in this process various by-products can be formed, designing highly selective catalysts is of great importance. In this line, we wish to report a novel catalyst that benefits from strong acidity, high specific surface area and thermal stability, which can selectively form solketal in glycerol acetalization. To prepare the catalyst, hierarchical zeolite was prepared via a novel method, in which partially dealuminated NaY was treated with PluronicF-127 and then reacted with NH4NO3 to furnish the H-form zeolite. Hierarchical faujasite was then achieved through calcination and template removal. Subsequently, it was functionalized with ionic liquid and used for the immobilization of heteropolyacid. The results indicated the importance of the mesoprosity of zeolite and the presense of ionic liquid functionality for achiveing high solketal yield. Moreover, among three investigated heteropolyacids, phosphomolybdic acid exhibited the highest catalytic activity. In fact, using 10 wt% catalyst at 55 °C and glycerol to acetone molar ratio of 1:20, solketal with yield of 98% was furnished under solvent-less condition. Besides, the catalyst was recyclable with low leaching of heteropolyacid.

Heterogeneous Co1/P1Mo12O40 single-atom catalyst for CO oxidation via termolecular Eley-Rideal (TER) mechanism

Catalytic mechanisms, micro-kinetic and thermodynamics studies of Phosphomolybdic acid (PMA) supported non-noble metal (NNM1 = Sc1, Ti1, V1, Cr1, Mn1, Fe1, Co1, Ni1, Cu1, and Zn1) single-atom catalysts (SACs) are explored for carbon monoxide (CO) oxidation by using DFT calculations. The results reveal that Co1/P1Mo12O40 have demonstrated excellent ability to adsorb (CO, O2) molecules, resulting in significant charge transfer from the catalyst surface to the adsorbate, which is essential to produce CO2 under normal reaction conditions. The various reaction pathways, including Eley Rideal (ER), Langmuir Hinshelwood (LH), Termolecular Eley Rideal (TER), and Mars Van Krevelen (MvK) are explored for CO oxidation on Co1/P1Mo12O40 to authenticate the most auspicious reaction mechanism. The energy barrier for the TER mechanism was 0.41 eV, lower as compared to the other reported materials which suggests that the Co1/P1Mo12O40 SACs would be the most appropriate future material for CO oxidation. To further validate the results, we performed the microkinetic investigation which predicts the CO oxidation rate of 4.58 × 106 s − 1. The key role of spin-magnetic moment for the promotion of CO oxidation by using Co1 single-atom catalyst was revealed from the deep electronic analysis. The current results would provide appreciated guidelines for experimentalists to develop less expensive and more effective non-noble metal SACs for CO oxidation.

Three-dimensional Anatomy of the Velopharyngeal Muscles in the Cleft Palate.

We have used micro-computed tomography (CT) to elucidate the relationship between the muscle fibers in specimens with cleft palate. These findings could be useful for muscle reconstruction in cleft palate repair and to better understand cleft palate speech. Cadaveric anatomical study. This study included three specimens with cleft palate. The specimens were stained with phosphomolybdic acid and scanned by Micro-CT. The anatomy of the muscles. Using 2D projection images and 3D reconstruction models, subtle anatomical structures could be observed in the muscles. The attachment of the levator veli palatini (LVP) was not at the posterior edge of the hard palate or palatine aponeurosis (PA), but at the anterior 21.71-44.2% of the cleft edge. The palatopharyngeal (PP) was composed of two bundles: inferior and superior heads, which clasped the LVP. The uvularis was unevenly distributed, and located on both sides of the cleft edge, originating at the edge. The palatoglossus, superior constrictor of pharynx and anatomical structure around the pterygoid hamulus, were normal. The PA, PP and LVP were attached to the cleft edge from front to back, in that order. The position of the uvularis was not fixed. With the help of Micro-CT technology, detailed anatomical features and the relationship between muscles could be visualized. In the specimen with cleft palate, muscles in the soft palate were associated with the pharyngeal muscles, which formed the 3D "velopharyngeal muscles complex." These findings provide anatomical evidence for muscle reconstruction in cleft palate repair.

Surface Adsorption of Amorphous Phosphate on RuNi-Doped Molybdate for the Hydrogen Evolution Reaction.

Developing highly active and cost-effective electrocatalysts is critical for enhancing the intrinsic performance of electrocatalytic water splitting. Oxoanion-based compounds, such as phosphates and molybdates, have emerged as promising electrocatalysts owing to their advantageous properties of nontoxicity, low price, and strong water adsorption ability. However, their relatively inferior activity has impeded extensive investigation into electrochemical applications. Herein, an amorphous phosphate-adsorbed and RuNi-doped molybdate (RuNiMo-P) composite is synthesized on nickel foam (NF) support by using a simple two-step method. Significantly, an acidic solution of phosphomolybdic acid (PMo12), containing a low concentration of Ru, can etch the NF, contributing to the in situ growth of the RuNi-doped molybdate precursor. Subsequent phosphating ensures the surface formation of the amorphous phosphate layer due to abundant oxygen in the precursor. The strong structural interaction between RuNi-doped molybdate and amorphous phosphate in RuNiMo-P prompts an enhanced hydrogen evolution reaction (HER) performance, delivering an overpotential of 38 mV at a current density of -10 mA cm-2, a Tafel slope of 53 mV dec-1, and good stability in an alkaline medium. Characterizations after HER reveal that RuNi doping, partial dissolution of phosphate and molybdate species, and newly formed NiOOH nanosheets can expose active sites, facilitate charge transfer, and modify electronic structures, thereby improving the HER performance effectively.

Inverted organic tandem solar cells with a charge recombination stack employing spatially confined p-type electrical doping

We report on the application of solution-based p-type electrical doping using 12-molybdophosphoric acid hydrate (PMA) to the fabrication of organic tandem solar cells. Such a doping approach leads to a spatially confined vertical doping profile down to a limited depth from the surface of polymer films, thus allowing the hole-collecting component of the charge recombination stack to be embedded in the photoactive layer of the bottom sub-cell. This simplifies the device architecture by removing the need for an extra dedicated hole-collecting layer. It is shown that this novel charge recombination stack comprising a PMA-doped bottom photoactive layer and a trilayer of Ag/AZO/PEIE is compatible with a solution-processed top photoactive layer. The fabricated inverted organic tandem solar cells exhibit an open-circuit voltage that is close to the sum of the open-circuit voltages of the individual sub-cells, and a fill factor that is close to the better fill factor of the two sub-cells.

Instability mechanism of phosphomolybdic acid solution and its effect on organic solar cells as a hole-transporting layer

Instability mechanism of phosphomolybdic acid solution and its effect on organic solar cells as a hole-transporting layer

Electrochemically-selective electrode for quantification of dorzolamide in bulk drug substance and dosage form

Three smart carbon paste electrodes were fabricated to quantify dorzolamide hydrochloride DRZ, including conventional carbon paste I, modified carbon paste embedding Silica II, and modified carbon paste embedding β-cyclodextrin III. This study is based on the insertion of DRZ with phosphomolybdic acid to create an electroactive moiety dorzolamide-phosphomolybdate ion exchanger using a solvent mediator dibutyl phthalate. The three constructed carbon paste electrodes displayed Nernstian responses and linear concentration ranges with lower detection limits. The vital performance of the created electrodes was verified in relation to various parameters. The electrodes enhance the selective determination of DRZ in the presence of inorganic ions, a co-formulated drug in the dosage form timolol maleate, and the excipient benzalkonium chloride. The modified carbon paste electrode including Silica was utilized to detect DRZ in ophthalmic eye drop form utilizing the direct calibration curve and potentiometric titration methods. Satisfactory findings were achieved by comparing them to other reported methods.

Highly Efficient and Reusable Denitrogenation Adsorbent Obtained by the Fluorination of PMA-MIL-101.

A simple but efficient strategy to improve the ability of adsorptive denitrogenation (ADN) of MIL-101(M101) was studied by the in situ encapsulation of phosphomolybdic acid (PMA) and the subsequent purification of the as-synthesized product by the NH4F solution. After the NH4F treatment, the vast majority of PMA was removed, loss of organic ligand (BDC) was observed, and the fluorination of the hydroxyl group in the M101 structure occurred. The ADN activities of the Cr-MOF matrix composites before and after fluorination were studied in detail. The rest of PMA interacts strongly with M101 and assists the ADN activity. Coordination unsaturated metal sites (CUS) in M101 are formed after fluorination and also contribute to ADN activity. Further, fluoride anions replace most of the hydroxide groups in M101, which can promote the ADN of quinoline (QUI) and indole (IND) through an acid-base interaction and N-atom coordination with the CUS in M101. P-M101-F 5% exhibits the highest adsorptive capacity and excellent regeneration ability. Special emphasis in this work is placed on structure modulation (including PMA doping, CUS creation, and fluorination) of M101 for enhancing ADN activity, which provides a useful scaffold for future research in the rational design of MOF-based ADN catalysts.

Hybrid Sub-1 nm Nanosheets of Co-assembled MnZnCuOx and Polyoxometalate Clusters as Anodes for Li-ion Batteries.

Transition metal oxide (TMO) anode materials in lithium-ion batteries (LIBs) usually suffer from serious volume expansion leading to the pulverization of structures, further giving rise to lower specific capacity and worse cycling stability. Herein, by introducing polyoxometalate (POM) clusters into TMOs and precisely controlling the amount of POMs, the MnZnCuOx -phosphomolybdic acid hybrid sub-1 nm nanosheets (MZC-PMA HSNSs) anode is successfully fabricated, where the special electron rich structure of POMs is conducive to accelerating the migration of lithium ions on the anode to obtain higher specific capacity, and the non-covalent interactions between POMs and TMOs make the HSNSs possess excellent structural and chemical stability, thus exhibiting outstanding electrochemical performance in LIBs, achieving a high reversible capacity (1157 mAh g-1 at 100 mA g-1 ) and an admirable long-term cycling stability at low and high current densities.

Pd–Pt promoted HPMo/UiO-66 acid catalyst for n-hexane hydroisomerization for higher quality and cleaner fuel production: Catalytic activity and kinetic modeling

The preparation of catalysts with adequate stability for the n-hexane hydroisomerization reaction is always a challenge in refineries. Therefore, in this work, the metal-organic framework UiO-66, heteropoly phosphomolybdic acid (HPMo), and bifunctional (Pd + Pt)/HPMo/UiO-66 samples were synthesized, characterized by experimental techniques, and tested in the n-hexane hydroisomerization reaction. As a result, the microporous (0.2%Pd+0.3%Pt)/30%HPMo/UiO-66 bifunctional catalyst exhibited an iso-hexane selectivity of 86% and n-hexane conversion of 72.1% after 36 h of reaction time. In addition, the Langmuir-Hinshelwood model was used to examine the kinetics of this reaction due to the inhibitory effect of hydrogen. The results provided an acceptable fit to the experimental data and allowed the determination of the kinetic parameters. Accordingly, the apparent activation energy of this bifunctional catalyst and the adsorption heats of hydrogen and n-hexane were calculated at 26.27, −16.12, and −7.82 kJ mol−1, respectively.

Rational construction of visible-light-driven MIL-88A(Fe)@PMo12 heterojunction with S-scheme electron transfer pathway to activate peroxymonosulfate for degradation of organic pollutants

Coupling of photocatalysis and persulfate oxidation is a promising approach to remove refractory organic pollutants. In 2022, there are about 30 publications on this topic, and the frequency of citations for related articles has reached 1,100. But the rational design and engineering of a desirable photocatalyst is still a great challenge. Herein, a S-scheme heterojunction photocatalyst was prepared by incorporation of Keggin phosphomolybdic acid (PMo12) into MIL-88A(Fe) through a one-step hydrothermal method. The prepared catalyst was characterized by several techniques, and used as visible-light-driven photocatalyst to activate peroxymonosulfate for the degradation of pollutants. The optimal photocatalyst (MIL-88A(Fe)@PMo12-30) displayed the outstanding catalytic activity and good stability. In MIL-88A(Fe)@PMo12-30 system, the degradation rate of AR18 could be increased by 20.55 times compared pristine MIL-88A(Fe). PMS concentration, catalyst dosage, initial pH value, and dye concentration influenced AR18 degradation. The scavenging experiments and EPR analysis disclosed that reactive species (RSs), including SO4−, OH, O2−, h+, and 1O2 were generated. Basis on the band structure, reactive species, PL and electrochemical analysis, the enhanced photocatalytic performance of MIL-88A(Fe)@PMo12-30 was mainly ascribed to the intimate contact of both component and unusual S-scheme electron transfer path. This work may open new horizons to construct efficient POMOFs hybrid photocatalysts.

Nanoarchitectonics of Boron‐Nitride‐Supported Phosphomolybdic Acid as a Heterogeneous Catalyst for Conversion of Fructose to 5‐Hydroxymethylfurfural

AbstractThe catalytic conversion of lignocellulose derived products to value added chemicals are of high importance in the quest to solve energy crisis. In this work, we have prepared the phosphomolybdic acid (PMA) supported on boron‐nitride (BN) nanosheets via a facile hydrothermal process. A series of heterogeneous catalysts has been prepared by using varying quantities of BN and PMA. All the catalysts were examined for the conversion of fructose to 5‐hydroxymethylfurfural (5‐HMF) and one of them turns out to be the best catalyst. Different optimizations like catalyst amount, temperature and time have been performed using the best catalyst. Although the catalyst selectively forms 5‐HMF, the yield was relatively low, which could be explained using the zeta potential studies. However, it was interesting to note that an addition of H2SO4 (0.01 M) to the reaction mixture enhances the catalytic activity of the overall process and leads to the formation of levulinic acid (LA) in addition to 5‐HMF, which could be attributed to the increased acidity in the reaction mixture. Overall, this work provides deeper insights on the role of BN, PMA and H2SO4 in the conversion of saccharides to value‐added chemicals.

Oxidative magnetization of biochar at relatively low pyrolysis temperature for efficient removal of different types of pollutants

A novel oxidative magnetization, involving phosphomolybdic acid and Fe(NO3)3 co-promoted pyrolysis, was established to manufacture highly adsorptive magnetic biochars for adsorbing aqueous tetracycline, methylene blue, and Cr6+. The modification of phosphomolybdic acid greatly boosted the formation of γ-Fe2O3 and oxygen containing groups with enhancement of specific surface area and pore volume at 400 °C. Importantly, γ-Fe2O3 was stably fixed on surface in quasi-nanoscale. The oxidized magnetic biochar displayed 631.53, 158.45, 155.13 mg/g adsorption capabilities for tetracycline, methylene blue, and Cr6+ with 22.79 emu/g saturation magnetization, respectively. Oxygen containing groups and quasi-nanoscale γ-Fe2O3 served as key adsorption sites for these pollutants. A general oxidative magnetization was established for manufacturing high-performance magnetic biochar through phosphomolybdic acid/Fe(NO3)3 co-promoted pyrolysis at relatively low temperature.

Green pathway to the synthesis of some spirooxindole derivatives using NGO/PMA as a new and effective solid acid catalyst

Heteropoly acids as nontoxic, dual Lewis–Brønsted acids with high thermal stability can develop acid‐catalyzed reactions. Combining these catalysts with other materials is of great interest to enhance their efficiency and capability. Despite all the outstanding properties of heteropoly acids, their solubility in water and most organic solvents limits their application. So, in presented research, immobilization of phosphomolybdic acid (PMA) on prepared N‐doped graphene oxide (NGO/PMA) was done to synthesize a solid acid, green and effective catalyst for the multicomponent synthesis of three kinds of spirooxindole structures. The preparation of new NGO‐based solid acid catalyst was performed through a three‐step method and identified by FTIR, TEM, mapping elemental analysis, SEM, EDX, and XRD techniques. Reusability of the catalyst, short reaction times (1:20–2 h), green condition, and easy workup as well as high yield of products (90–95%) are some merits of this research.

Tuning Surface Modification of Potasium Boasted Phosphomolybdic Acid Catalysts for Selective Oxidative Esterification of Benzyl alcohol

Tuning Surface Modification of Potasium Boasted Phosphomolybdic Acid Catalysts for Selective Oxidative Esterification of Benzyl alcohol

Modified millet extract-mediated NiO/CaO Nanocomposite potentiometric sensor for monitoring of ciprofloxacin in commercial products

The super useful capability of nickel oxide (NiO) and calcium oxide (CaO) nanoparticles (NPs) has inspired critical interest in the usage of these nanomaterials as a wonderful and potentially active nanocomposite in ion selecting and detecting studies. This study created a NiO/CaO nanocomposite (NiO/CaO NCS) functionalized wire sensor to quantify ciprofloxacin (CPX) in medicines. Ciprofloxacin was coupled with phosphomolybdic acid (PMA) to give ciprofloxacin phosphomolybdate (CPX-PM) as an electrically active compound in the existence of polyvinyl chloride and the fluidizing medium o-nitrophenyl octyl ether (o-NPOE). The developed sensor exhibits exceptional sensitivity and selectivity for the measurement and estimation of CPX, with linearity ranging from 1.0 × 10−10 to 1.0 × 10−2 mol L−1. EmV = −57.25 ± 0.5 (log [CPX]) + 832.61 was estimated as the regression equation. In contrast, the standard type CPX-PM showed a potential response in a concentration range of 1.0 × 10−6 to 1.0 × 10−2 mol L−1 and a regression equation of EmV = −54.745 ± 0.7 (log [CPX]) + 469.34. The functionalized sensor was potentially utilized for the quantification of CPX in its commercial Tablets.

Effect of Vanadium on Phosphomolybdic acid structure and Catalytic evaluation of Solvent-free synthesis of 4-tert-butylphenol

Vanadium-modified phosphomolybdic acid (PMA) with different vanadium-to-phosphorus (V/P) mole ratio materials were synthesised and characterised by various techniques. XRD results established the formation of crystallite Keggin ions. Raman and FT-IR spectra data confirm the Keggin ion of heteropoly acid is retained after V loading into the PMA structure. TPD profile showed higher acidity at a lower V/P ratio than higher loadings. BET analysis showed a higher surface area at a lower V/P mole ratio than higher catalyst loadings. We evaluated the efficacy of the prepared materials as catalysts for the tertiary butylation of phenol. The lower V/P mole ratio material exhibited higher conversion and selectivity towards 4-tert-butyl phenol than other loadings. These findings support that V loading modifies the acidity of PMA, and the material demonstrates enhanced catalytic activity towards the desired product.

Visible light-assisted efficient degradation of Rhodamine B by N-TiO2/Mn-HPMo/Ag ternary composites

In this paper, Ag nanoparticles were deposited on the surface of nitrogen-doped titanium dioxide coupled with manganese-substituted phosphomolybdic acid composites (N-TiO2/Mn-HPMo) using photoreduction method to construct ternary photocatalysis-Fenton composite catalyst (N-TiO2/Mn-HPMo/Ag), and the degradation performance of the catalyst was evaluated with Rhodamine B (RhB) as the target pollutant. The results showed that the N-TiO2/Mn-HPMo/Ag ternary composite catalyst had remarkable visible light activity, and the degradation efficiency of RhB could reach 96.3% in 20 min under visible light. Meanwhile, UV–vis diffuse reflectance spectroscopy illustrated the promotion effect of Ag deposition on the visible light response of N-TiO2/Mn-HPMo. The behavior of photogenerated charges was also characterized by Surface Photovoltage Technique, which further demonstrated that Ag deposition not only extended the light absorption range but also enhanced the separation efficiency of photogenerated charges. This work provides favorable information for the construction of efficient catalysts with high activity under visible light.

Purification of crude terephthalic acid using phosphomolybdic acid supported on MCM-41 and TiO2 photocatalysts

The present research introduces the photocatalytic process for the conversion of 4-carboxybenzaldehyde to terephthalic acid through the synthesis of phosphomolybdic acid (PMo) supported on TiO2 and MCM-41 as the new class of photocatalysts for this application. As synthesized photocatalysts were characterized through XRD, FT-IR, N2 adsorption–desorption, and FESEM-EDS. It was found that the maximum conversion of 4-carboxybenzaldehyde to para-toluic acid was achieved by 25% PMo/TiO2 photocatalyst with a value of 97.85%. To investigate the effect of parameters such as UV irradiation power intensity, temperature, catalyst dosage, and persulfate concentration, Response Surface Methodology (RSM) was used. Finally, the experimental results showed the UV irradiation power intensity of 2.3 W/mL, the temperature of 24 °C, and the concentration ratio of terephthalic acid to persulfate and catalyst of 3.1 mg/mg and 7.2 mg/mg, respectively as the optimum values. At this operating condition, the concentration of 4-carboxybenzaldehyde decreased from 1870 ppm to 40.2 ppm after 90 min.