Iron Hydrogen Phosphate Research Articles

Design of biphasic Fe and Zn doped hydroxyapatite: Novel strategy for combating osteomyelitis infections

Hydroxyapatite (HA) bioceramics are widely used materials for orthopaedic applications, offering enhanced cellular adhesion and differentiation. However, the lack of antibacterial features makes the HA biomaterials prone to bacterial infections in in-vivo conditions. The osteomyelitis-like conditions are often treated with prolonged doses of antibiotics and may require surgical removal. Such problems can be tackled by inducing the antibacterial characteristics in the biomaterials which prevent such infections. Various research studies have been conducted to improve the mechanical and antibacterial characteristics of biomaterials like HA through doping. The present study focuses on the synthesis, characterization, and antibacterial study of Zn and Fe doped HA (ZFHAp) for application in the treatment of osteomyelitis. Response Surface Methodology (RSM) based Central Composite Design (CCD) approach was used to optimize the process parameters using the Design Expert software. The analyses indicated the presence of Calcium Iron Hydrogen Phosphate (CIHP) and Parascholzite (PS) as major phases. The optimized experimental conditions were estimated as 0.09 M Zn and 0.04 M Fe at 65 °C, corresponding to 71.29 % and 28.71 % of the CIHP and PS phases, respectively. The synthesized nanopowder showed mixed morphology comprising spherical and rod-shaped particles due to biphasic composition. The ZFHAp sample showed a broad-spectrum antibacterial activity, with IC50 values of 4.02 mg/ml and 4.79 mg/ml against E. coli and S. aureus, respectively. The optimized sample showed excellent biocompatibility with the osteoblast-like cells (MG-63) with improved biomineralization properties. The antibacterial and osteoinductive characteristics of the synthesized biphasic Fe and Zn doped HA suggest its potential application against osteomyelitis-related conditions.

Anion intercalated nickel iron hydrogen phosphate hydrate for full water splitting application

Exploration of effective and earth abundant electrocatalysts is essential for various renewable energy conversion technologies. The electrolysis of water into oxygen and hydrogen is one of the most promising methods to produce clean hydrogen fuel from electricity supplied by renewable energy sources. However, the high cost and rarity of conventional noble metal−based catalysts limit their practical applications. Hence, anion (NO3−) intercalated iron hydrogen phosphate supported on nickel foam (NiFeHP/NF) is fabricated for the first time by the combined hydrothermal and followed electrodeposition methods. The anion intercalation modifies the surface and electronic structure, thereby enhancing the oxygen evolution reaction (OER) and hydrogen evolution rection (HER). The NO3− intercalation increased the wettability of the catalyst and the contact between the electrode and electrolyte, thereby improving the mass transfer capability. The electrochemical analysis demonstrates that the NO3− intercalated for about 20 min over the NiFeHP/NF catalyst (NiFeHP-6) needs an overpotential of 280 and 265 mV only at a high current density of 100 mA cm−2 to drive OER and HER, respectively, in an alkaline 1M KOH electrolyte and outperforms the benchmark RuO2 catalyst fabricated on NF in OER.

INFLUENCE OF SOLID LIQUID STATES RATIOS ON THE COMPOSITION AND PROPERTIES OF HUMATE-CONTAINING ORGANO-MINERAL FERTILIZERS

Human economic activity leads to removal of nutrients from the soil along with the crop. Nutrients losses also occur because of natural processes (erosion, leaching, etc.). It is necessary to replenish the missing nutrients with the use of humate-containing organomineral fertilizers to preserve soil fertility and increase productivity. The purpose of this work is to study the processes of iron (III) phosphates interaction with potassium humate and to obtain humate-containing organomineral fertilizers. Methodology. Chemical analysis, infrared spectroscopy, X-ray phase analysis methods have been used. Results and discussion. The processes of obtaining humate-containing organomineral fertilizers by the interaction in the systems “iron dihydrogen phosphate - potassium humate”, “iron hydrogen phosphate - potassium humate” and “iron orthophosphate - potassium humate” have been studied. It has been determined that an increase in the S:L ratio from 1:3 to 1:6 leads to an increase in the content of the digestible forms of Р2О5 up to 44.70%, nitrogen up to 1.85% and the output of humic substances up to 79.23%. An analysis of the IRS data indicates the multicomponentness and complexity of the composition of humate-containing organomineral fertilizers samples. Conclusion. It has been shown that the absorption bands of humic compounds of various functional groups and various substitutions phosphates are superimposed, while the shape of the absorption bands distorted, and their maxima have shifted to the high- or low-frequency area. It has been found that, regardless the phosphate ionnature, an increase in the ratio of S:L leads to a decrease in the absolute content of total, water-soluble and assimilable forms of P2O5. Concurrently, the phosphate part almost completely converted into the assimilated form. It has been defined that adding of the potassium humate, makes all phosphorus, which is in the indigestible form in the iron phosphates, almost completely pass into a mobile and assimilable form. It has been revealed that the addition of potassium humate into the systems with iron phosphates of various degrees of substitution makes it possible to neutralize the residual acidity of the pulp, and the neutralization process proceeds without P2O5 retrogradation. The resulting products have good physical, mechanical and fertilizer properties.

Laser-induced immobilization of an amorphous iron-phosphate/Fe3O4 composite on nickel foam for efficient water oxidation.

A laser-induced immobilization strategy is applied to prepare an amorphous iron-phosphate/Fe3O4 (L-FePO) composite on a nickel foam (NF) support. By laser-irradiating an iron hydrogen phosphate (FeHP) precursor, a melting and oxidation process leads to the generation of L-FePO with hierarchical pores and an amorphous structure. L-FePO shows exceptional electrocatalytic performance for the OER in an alkaline electrolyte, demonstrating an overpotential of 256 mV at 100 mA cm-2, a Tafel slope of 71 mV dec-1, and good stability over 100 h. The active Fe3O4, partially dissolved phosphate, and newly formed FeOOH species provide abundant active sites, contributing to the excellent OER performance.

Nickel foam as conductive substrate enhanced low-crystallinity two-dimensional iron hydrogen phosphate for oxygen evolution reaction

Abstract Cheap and excellent conductive substrates with large and manipulated geometric area have become an indispensable research object for non-self-supporting OER electrode materials to achieve the practical application. In this study, low-crystallinity 2D morphology iron hydrogen phosphate material (FPO3) with thickness of 12–16 nm is obtained by an easy polyol refluxing method. Its overpotential drop-casted on nickel foam (FPO3/NF) for OER is just 309 mV at the current density of 10 mA cm−2. Through the detailed comparative analysis, its number and the intrinsic activity of active sites for OER effectively enhanced because of the two-dimensional morphology, the low crystallinity, the excellent redox activity of iron, and the more beneficial synergy between NF and FPO3. Those results also indicate that using NF as the substrate is a high-efficiency method to realize the practical application of non-self-supporting electromaterials by a simple drop-casted treatment.

Mechanical and physical properties of inorganic polymer cement made of iron-rich laterite and lateritic clay: A comparative study

In this work, two different laterites (iron contents of 13.07 and 49.34 wt%, respectively, for lateritic clay, LAC, and iron-rich laterite, LAI) were selected and calcined at 600 °C. The obtained calcined laterites, namely LAI600 and LAC600, were separately mixed with an alkaline solution (silicate modulus of 1.35) or an acidic solution (phosphoric acid solution at pH ≤ 2) for the synthesis of inorganic polymer products. The fabricated products were cured at 20 °C (ambient) and 40 °C (oven). The obtained results showed that the compressive strength of each series of alkaline-based inorganic polymer binder increased with ageing time (7 and 28 days) for room temperature curing, while the reverse trend was noted for oven-cured specimens. The best mechanical performance was obtained when using a phosphoric acid solution, 38 and 52 ± 1 MPa; 62 and 65 ± 1 MPa at 28 days for LAC and LAI respectively. It appeared that a higher iron content within the laterite contributed to an increase in the compressive strength under acidic conditions (LAI (59 MPa) > LAC (48 MPa)) compared to the behavior obtained under alkaline conditions (LAI (6 MPa) < LAC (29 MPa)). Accordingly, the acidic products exhibited a dense structure (with lower porosity) and contained amorphous iron/aluminium phosphate phases such as berlinite (FePO4), iron hydrogen phosphate hydrate (Fe3H15(PO4)8·4H2O), ferrowyllieite (AlFe2Na2(PO4)3) and sodium iron phosphate (Na3Fe2(PO4)3) arising from the alteration of iron minerals in an acidic medium, confirmed by Mössbauer spectroscopy and electron paramagnetic resonance spectroscopy.

Study of Microbially Influenced Corrosion in the Presence of Iron-Oxidizing Bacteria (Strain DASEWM2)

The present study deals with the investigation of microbially influenced corrosion of mild steel by the iron-oxidizing bacterium (IOB), Pseudomonas sp. strain DASEWM2, using electrochemical tests, immersion tests, and surface analysis. The corrosion rate obtained by Tafel plots was higher after exposure of ~ 24 h to 72 h when the concentration of sessile cells and constituents of extracellular polymeric substances were high. In inoculated media, cyclic polarization curves show lower pitting potential, repassivation potential, and large area under the hysteresis loop, indicating higher susceptibility of steel to localized corrosion. Immersion tests show higher corrosion rate (0.252 ± 0.05 mpy) and large deep pits in the open area (maximum pit depth 140 ± 8 µm) and under crevice (maximum pit depth 95 ± 4 µm) indicating a higher degree of corrosion in inoculated media. Corrosion products formed on corroded steel samples were analyzed using EDAX, XRD, and FTIR techniques. Goethite and lepidocrocite are the main corrosion products in the case of inoculated media. In contrast, lepidocrocite and iron hydrogen phosphate are the main corrosion products in the case of control media. The absence of iron hydrogen phosphate, a protective type of corrosion product, on steel exposed to inoculated media may be responsible for observing a higher degree of corrosion due to bacteria.

Phosphorus recovery from the liquid phase of anaerobic digestate using biochar derived from iron−rich sludge: A potential phosphorus fertilizer

A novel technique for phosphorus recovery from the liquid phase of anaerobic digestate was developed using biochar derived from iron−rich sludge (dewatered sludge conditioned with Fenton’s reagent). The biochar pyrolyzed from iron−rich sludge at a low temperature of 300 °C (referred to as Fe−300 biochar) showed a better phosphorus (P) adsorption capacity (most of orthophosphate and pyrophosphate) than biochars pyrolyzed at other higher temperatures of 500–900 °C, with the maximum P adsorption capacity of up to 1.843 mg g−1 for the liquid phase of anaerobic digestate. Adsorption isotherms study indicated that 70% P was precipitated through chemical reaction with Fe elements, i.e., Fe(II) and Fe(III) existed on the surface of the Fe−300 biochar, and other 30% was through surface physical adsorption as simulated by a dual Langmuir-Langmuir model using the potassium dihydrogen orthophosphate (KH2PO4) as a model solution. The seed germination rate was increased up to 92% with the addition of Fe−300 biochar after adsorbing most of P, compared with 66% without the addition of biochar. Moreover, P adsorbed by the chemical reaction in form of iron hydrogen phosphate can be solubilized by a phosphate-solubilizing microorganism of Pseudomonas aeruginosa, with the total solubilized P amount of 3.045 mg g−1 at the end of an incubation of 20 days. This study indicated that the iron−rich sludge−derived biochar could be used as a novel and beneficial functional material for P recovery from the liquid phase of anaerobic digestate. The recovered P with biochar can be re-utilized in garden soil as an efficient P−fertilizer, thus increasing the added values of both the liquid phase of anaerobic digestate and the iron−rich sludge.

Design and controllable growth of stylish flower-like iron hydrogen phosphate peroxidase mimic with effective catalytic performance

The applications of inorganic micromaterials as enzyme-like catalysts are receiving much attention owing to high efficiency, stability, and low cost. However, few reports have focused on the structure and applications of peroxidase mimic in organic reactions. Herein, we have synthesized an enzyme-like iron hydrogen phosphate crystal with a unique micro-flower hierarchical structure following a controllable low-temperature hydrothermal process by self-assembling, and we used as a catalyst in the oxidation reactions for the first time. The peroxidase mimic with new morphology exhibited excellent enzyme-like catalytic performance in the oxidation of benzyl alcohol by H2O2. This catalyst has higher catalytic activity and better stability at specific temperature and pH ranges than natural peroxidases.

Corrosion of steel due to iron oxidizing bacteria

PurposeThe purpose of this study is to investigate microbial influenced corrosion of steel because of iron oxidizing bacteria (IOB).Design/methodology/approachCarbon steel was selected for this study. Winogradsky media was used for isolation of IOB and as test solution for corrosion measurements. Electrochemical tests and immersion test were conducted to estimate the corrosion rate and extent of pitting. The corroded surface was analysed by SEM and corrosion products formed over the metal surface were identified by XRD and Fourier transformed infrared. Biofilm formed over the corroded metal was analysed by UV-visible spectroscopy for its extracellular polymeric substances (EPS) constituents.FindingsPresence of IOB in Winogradsky medium enhances corrosion. Uniform and localized corrosion increases with increased bacterial concentration and EPS constituents of the biofilm. Iron sulphite formation as one of the corrosion products has been suggested to be responsible for increased corrosion attack in the inoculated media in comparison to control media where corrosion product observed is iron hydrogen phosphate which is protective in nature.Originality/valueThis work correlates increased corrosion of steel in the presence of bacteria with the nature of corrosion products formed over it in case of IOB. Formation of corrosion products is governed by various electrochemical reactions; hence, inhibition of such reactions may lead to reduce or stop the formation of such products which enhances corrosion and thereby may reduce the extent of microbial induced corrosion.

Synthesis of Hierarchical Iron Hydrogen Phosphate Crystal as a Robust Peroxidase Mimic for Stable H2O2 Detection

To develop a green, cost-efficient and robust peroxidase mimic, micro/nano hierarchical morphology (for ease of separation and reuse), relative chemically stable composition (for ease of storage) and stable crystal structure (for long-term stability) are highly desired. Herein, using phosphoric acid as a chelating ligand to control the release of iron ions, hierarchical iron(III) hydrogen phosphate hydrate crystals are successfully prepared by nanosheets formation and following self-assembling in a facile low-temperature hydrothermal process. They are first found to have peroxidase-like activity and showed higher affinity for H2O2 and lower affinity for 3,3',5,5'-tetramethylbenzidine compared with horseradish peroxidase. The affinity feature is used for quantitative detection of H2O2 and shows a wide linear detection range from 57.4 to 525.8 μM (R(2) = 0.994) with a low detection limit of 1 μM. Benefited from chemical stability of hierarchical iron(III) salt crystals, they own good reproducibility (relative standard deviation = 1.95% for 10 independent measurements), long-term stability (no activity loss after 10 cycles), and ease of recovery (by simple centrifugation). Because the method is easily accessible, iron hydrogen phosphate hierarchical crystals have great potential for practical use of H2O2 sensing and detection under harsh conditions.

Synthesis and crystal structures of iron hydrogen phosphates

Three new iron hydrogen phosphate compositions have been synthesised under hydrothermal conditions; Fe(II)2O(HPO4) ( 1), (NH4)3Fe(III)3(HPO4)6 ( 2) and Fe1.34(III)(PO4)OH0.96 ( 3). 1 and 2 have framework structures constructed from FeO6 octahedra and HPO4/PO4 tetrahedra containing cavities; in the case of 2, these are occupied by ammonium cations while in 1 they are cross linked by hydrogen bonding involving the HPO4 groups. Crystals of 3 grow as 30 m octahedral jackstones and this synthetic material adopts the structure from the Lipscombite solid solution. Thermal decomposition of these materials yields simple iron phosphates and the potential of these compounds and their derivatives, formed for example through Li+-ion exchange of NH4+, for battery applications is discussed.

A study of phosphate absorption by magnesium iron hydroxycarbonate

A study of the mechanism of phosphate adsorption by magnesium iron hydroxycarbonate, [Mg(2.25)Fe(0.75)(OH)(6)](CO(3))(0.37).0.65H(2)O over a range of pH has been carried out. The efficiency of the phosphate removal from aqueous solution has been investigated between pH 3-9 and the resulting solid phases have been studied by elemental analysis, XRD, FT-IR, Raman, HRTEM, EDX and solid-state MAS (31)P NMR. The analytical and spectroscopic data suggest that phosphate removal from solution occurs not by anion intercalation of the relevant phosphorous oxyanion (H(2)PO(4)(-) or HPO(4)(2-)) into the LDH but by the precipitation of either an insoluble iron hydrogen phosphate hydrate and/or a magnesium phosphate hydrate.

Heptairon Bis(phosphate) Tetrakis(hydrogenphosphate).

AbstractFor Abstract see ChemInform Abstract in Full Text.

Heptairon bis(phosphate) tetrakis(hydrogenphosphate).

A new iron hydrogen phosphate, heptairon bis(phosphate) tetrakis(hydrogenphosphate), Fe(7)(PO(4))(2)(HPO(4))(4), has been prepared hydrothermally and characterized by single-crystal X-ray diffraction. The compound has one Fe atom on an inversion centre and is isostructural with Mn(7)(PO(4))(2)(HPO(4))(4) and Co(7)(PO(4))(2)(HPO(4))(4). The structure is based on a framework of edge- and corner-sharing FeO(6), Fe(5) and PO(4) polyhedra, isotypic with that found in the mixed-valence iron phosphate Fe(7)(PO(4))(6). The Fe atoms in the title compound are purely in the divalent state, just like the Co atoms in Co(7)(PO(4))(2)(HPO(4))(4), the necessary charge balance being maintained by the addition of H atoms in the form of bridging Fe-OH-P groups.

Characterization of Delhi iron pillar rust by X-ray diffraction, Fourier transform infrared spectroscopy and Mössbauer spectroscopy

Rust samples obtained from the region just below the decorative bell capital of the Delhi iron pillar (DIP) have been analyzed by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and Mössbauer spectroscopy. The identification of iron hydrogen phosphate hydrate in the crystalline form by XRD was unambiguous. Very weak diffraction from the oxyhydroxides/oxides of iron was observed indicating that these phases are most likely to be present in the amorphous form in the rust. The present XRD analysis of rust obtained from an inaccessible area of the DIP has also been compared with earlier analyses of DIP rust obtained from regions accessible to the public. FTIR indicated that the constituents of the scale were γ-, α-, δ-FeOOH, Fe 3− x O 4 and phosphate, and that the scale was hydrated. The unambiguous identification of the iron oxides/oxyhydroxides in the FTIR spectrum implied that they are present in the amorphous state, as XRD did not reveal these phases. The FTIR results have also been compared with earlier FTIR spectroscopic results of atmospheric rust formation. Mössbauer spectroscopy indicated that the rusts contained γ-FeOOH, superparamagnetic α-FeOOH, δ-FeOOH and magnetite, all in the amorphous form. The Mössbauer spectrum also confirmed that iron in the crystalline iron hydrogen phosphate hydrate, whose presence was confirmed by XRD, was in the ferric state indicating that it was a stable end corrosion product.

On the corrosion resistance of the Delhi iron pillar

The nature of the protective passive layer on the corrosion resistant Delhi iron pillar (DIP) has been addressed based on a detailed characterization of its rust. Rust characterization clearly established that the major constituents of the scale were crystalline iron hydrogen phosphate hydrate (FePO 4·H 3PO 4·4H 2O), α-, γ-, δ-FeOOH and magnetite. The iron oxide/oxyhydroxides were present in the amorphous form. The role of slag particles in the matrix of the DIP iron in enhancing the passive film formation is briefly addressed initially. The process of protective rust formation on DIP iron is outlined based on the rust analysis. Initially, the corrosion rate of iron is high due to the presence of slag particles. This results in enhancement of surface P content. In the presence of P, the formation of a protective amorphous compact layer of δ-FeOOH, next to the metal surface, is catalyzed and this confers the initial corrosion resistance. The critical factor contributing to the superior corrosion resistance of the DIP, however, is the formation of iron hydrogen phosphate hydrate, as a thin layer next to the metal–metaloxide interface. The formation of the crystalline modification of this phosphate from the amorphous form is aided by alternate wetting and drying cycles (i.e. the environmental factor). The rate of corrosion is further lowered due to the low porosity content of the crystalline phosphate phase. The passive film formation on the DIP has been contrasted with the rusting of normal and weathering steels.

Preparation and crystal structure of a new acentric caesium iron hydrogen phosphate, Cs3Fe3H15(PO4)9

AbstractSingle crystals of caesium iron hydrogen phosphate, Cs3Fe3H15(PO4)9, 2, were prepared hydrothermally by heating caesium iron dihydrogenphosphate, CsFe(H2PO4)4, 1, with a small amount of water. 2 crystallizes orthorhombic, space group Pna21 (No. 33 Int. Tab.) with Z = 4 and a = 2718(1), b = 908.1(3), c = 1280.8(4) pm.The crystal structure was solved by using 4734 unique reflections I &gt; 2σ(I) with a final wR2 value of 0.0801 (SHELXL‐93).The main feature of the crystal structure are channels formed by combined PO4‐tetrahedra and FeO6‐octahedra along the [001] direction. Cs+ is placed inside of the channels. Effective Coordination Numbers (ECoN), Mean Fictive Ionic Radii (MEFIR), Charge Distribution (CHARDI) and the Madelung Part of Lattice Energy (MAPLE) are calculated for the title compound.