Triphosphonic Acid Research Articles

Magnetic nanoadsorbent functionalized with aminophosphonic acid for NdIII ion extraction from aqueous media

The adsorption performance of a new magnetic nanoadsorbent of Nd3+ was investigated. First, the nanoadsorbent was synthesized by chemical coprecipitation, and covered with a silica layer by the sol–gel method to obtain the silica-coated magnetic nanoparticles (MNP@SiO2). Subsequently, it was functionalized with nitrilotris(methylene)triphosphonic acid(NTMP), obtaining the goal aminophosphonic-functionalized nanoadsorbent (MNP@SiO2-NTMP). The functionalized nanoadsorbent was characterized using TEM, XRD, VSM, TGA, ATR-FTIR, EDS, and zeta potential measurements, confirming its nanoscale size, superparamagnetic behavior, and the presence of surface amino-phosphonic groups. The influence of different operational parameters on neodymium adsorption was investigated. The highest adsorption capacity of neodymium(III) was approximately 18 mg·g−1 at pH 6.8, using an adsorbent dose of 1 g·L-1, a neodymium concentration of 100 mg·L-1, and a contact time of 15 min at room temperature. The neodymium(III) adsorption onto MNP@SiO2-NTMP followed a pseudosecond-order model, suggesting chemisorption mechanisms as the rate-limiting step. Batch experimental results showed that Nd3+ adsorption onto MNP@SiO2-NTMP was independent of the ionic strength, indicating the formation of inner-sphere surface complexes.Furthermore, the adsorption thermodynamic analyses suggested that neodymium adsorption was exothermic, entropy decreasing, and more favorable at low temperatures. The best adsorbent regeneration and neodymium desorption from the loaded adsorbent was achieved using acidic solutions of H2SO4, exhibiting excellent adsorbent reusability throughout the four adsorption–desorption cycles. The MNP@SiO2-NTMP was an effective adsorbent material for extracting neodymium(III) from dilute aqueous solutions. Therefore, it is expected that MNP@SiO2-NTMP can potentially be used in more sustainable recovery methods of neodymium from secondary sources, for example, from leaching solutions of NdFeB magnet scraps.

Phosphonate removal from membrane concentrate by electro-coagulation

In this study, the efficiency of electrocoagulation (EC) with iron electrodes was applied to remove two phosphonates, 1-hydroxyethylidene-1, 1-diphosphonic acid (HEDP) and nitrilotris(methylene) triphosphonic acid (NTMP) from concentrates. This work provides a detailed description of the experimental procedure and results on phosphonate removal and recovery from different electrolytes, including synthetic and real reverse osmosis (RO) membrane concentrates. This research showed high selectivity of EC, removing 100% and 80% of the NTMP and the HEDP respectively, confirming no competition with sulfates, nitrates, or silica. When experimenting with other electrolytes, calcium showed to be critical in enhancing the flocculation process, while calcium carbonate precipitation contributed to capturing the phosphonates from the concentrate. The produced iron oxide (sludge) was confirmed as goethite and akaganéite, and finally transformed into hematite, indicating the oxidation from Fe2+ to Fe3+ during the EC process. After the iron precipitate collection, an alkaline wash of the sludge was enough to recover 100% of the initial phosphorus from the NTMP phosphonate. However, further research is needed to optimize the recovery procedure and to improve the results with the HEDP. 70 and 140 A·m−2 current densities were optimal to bring HEDP and NTMP concentrations down to 32 μM (1 mg·L−1) in only 30 and 10 min respectively. In these conditions, the operational costs, 1.10 and 0.03 €·m−3 of treated concentrate, were estimated for HEDP and NTMP respectively. Even when EC has been widely studied for phosphate removal, this technique has been barely applied to treat concentrates containing phosphonate-based antiscalants. EC opens new possibilities for phosphonates and phosphorus to be removed and recovered respectively from membrane and other concentrates.

Synthesis and evaluation of scale inhibitor with high-temperature resistance and low corrosion capability for geothermal exploitation

Scale and corrosion issues of well pipelines become more prominent in geothermal exploitation at temperatures exceeding 100 °C. Effective scale and corrosion inhibitors are the keys to addressing the concerns. In this study, maleic anhydride (MA), acrylic acid (AA), 2-acrylamide-2-methylpropane sulfonic acid (AMPS), sodium hypophosphite, and sodium dodecyl sulfate (SDS) were utilized to synthesize a multi-polymer scale inhibitor PZGS with high-temperature resistance and low corrosion capability for geothermal exploitation. The functional groups and molecular weight of PZGS were analyzed by Fourier transform infrared spectroscopy (FTIR) and gel permeation chromatography (GPC). The scale inhibitor contains carboxylic acid groups, amide groups, phosphonic acid groups, and sulfonic acid groups. These groups ensure the capability of PZGS to chelate Ca2+, thus promoting the lattice distortion of calcium carbonate scale and improving its scale inhibition performance and temperature resistance. The number average molecular weight and the weight average molecular weight of PZGS are 5446 g/mol and 7139 g/mol respectively. The scale inhibition rate of 480 mg/L PZGS could reach 95% at 150 °C which is better than common scale inhibitors such as nitrogen trimethyl triphosphonic acid (ATMPA) and diethylenetriamine pentamethylene phosphonic acid (DTPMPA), whose inhibition rates are just 62% and 60% at 150 °C respectively. With the increase of the concentration, the formation of aragonite and vaterite gradually increased while calcite decreased because of the chelation and lattice distortion of polycarboxylic acid groups, phosphonic acid, sulfonic acid, and other groups from PZGS over the calcium carbonate scale. The compound formula “240 mg/L PZGS plus 200 mg/L polyepoxysuccinic acid (PESA)" performed the best effectiveness in its anti-scale and low corrosion capability. Its scale inhibition rate on the calcium carbonate scale was 94.1% at 150 °C, and the corrosion rate of the KLF carbon steel corrosion test piece was only 0.35 g/(m2·h) due to the PESA film coverage. Compared with 0.94 g/(m2·h) from brine solution and 0.91 g/(m2·h) from 240 mg/L PZGS, the corrosion rate of the compound formula was reduced by 63.2% and 61.7% in simulated geothermal water respectively. The findings of this study can provide effective guidelines for the development of scale and corrosion inhibitors for geothermal exploitation.

Three-Component Solvent-Free Synthesis of 3, 4-Dihydropyrimidones and Thiones by Iron-Phosphonate Nanoparticle

Organic-inorganic hybrid nanomaterials have been prepared through cooperative assembly of cetyltrimethylammonium bromide (CTAB), Iron(ΙΙΙ)nitrate, and (Nitrilotris(methylene)) triphosphonic acid (NMPA). Surfactant is used as a structure directing agent, while the other two chemicals are used as precursors for the formation of pore walls. The structure of the synthesized iron phosphonate nanomaterials was fully characterized by using different spectra such as FT-IR, VSM, thermal gravimetric analysis (TGA), scanning electron microscopy (SEM), EDX and XRD. The SEM analyze confirmed a hollow spherical micromorphology with well-defined porosity. Obtained hybrid organic and inorganic Nano catalyst has high performance in the synthesis of heterocyclic compounds. Therefore, the reaction of aldehyde aromatic, urea and ethyl acetoacetate was performed in the presence of the catalytic amount of Fe- NMPA under solvent-free conditions. The 3, 4-dihydropyrimidin (1H)-ones/thiones derivatives were obtained in high yield and short reaction time. The products of the reaction were characterized by physical data and FT-IR spectrum. This method has several advantages such as a recyclable catalyst, easy workup, and not using a volatile organic solvent.

Construction of Novel Proton Transport Channels by Triphosphonic Acid Proton Conductor-Doped Crosslinked mPBI-Based High-Temperature and Low-Humidity Proton Exchange Membranes

High proton conductivity and sufficient stability of the polybenzimidazole membrane are important for the application of high-temperature proton exchange membrane fuel cells (HT-PEMFCs). A series of composite membranes based on crosslinked mPBI (cPBI) with cerium 2,4,6-triphosphono-1,3,5-triazine (CeTPT) were resoundingly fabricated. Novel cPBI networks with tetrafunctional N,N,N′,N′-tetraglycidyl-4,4′-diaminodiphenylmethane (TGDDM) were synthesized. It is noteworthy that a new high-temperature proton conductor CeTPT was added. CeTPT contained three phosphonic acid groups, which offered good proton conductivity at moderate-to-low humidity and had good thermal stability. Tetrafunctional crosslinker TGDDM had multiple functional groups. With a relatively low crosslinking degree (CLD), the mechanical properties, dimensional stability, and oxidative resistance of the membranes were efficiently improved. The low CLD and good physicochemical stability also allowed high doping levels of CeTPT (up to 50%) and consequently high proton conductivity. At 180 °C and 50% RH, the proton conductivity of cPBI-5-CeTPT-50 and cPBI-10-CeTPT-50 was 0.072 and 0.068 S cm–¹, respectively. The cPBI-CeTPT membranes showed good methanol resistance and membrane selectivity, and thus the membranes were suitable for direct methanol fuel cells.

Triphosphonic acid modified multi-walled carbon nanotubes for gold ions adsorption

Triphosphonic acid modified multi-walled carbon nanotubes (TPA-MWCNTs) have been developed in a facile method and then characterized and used for gold ion adsorption. The adsorption behaviors of TPA-MWCNTs for Au(III), including the effect of pH, adsorption isotherm, adsorption kinetics, adsorption thermodynamics, and regeneration properties have been investigated, and the maximum adsorption capacity of TPA-MWCNTs obtained from the Langmuir isotherm is 980.39 mg/g at 35 °C. Moreover, the adsorption process optimization has been conducted by using response surface methodology (RSM) and the analysis of variance (ANOVA). Therefore, TPA-MWCNTs can be used as an efficient adsorbent in wastewater treatment and gold uptake.

Two novel zinc(II) phosphonates for the selective luminescence sensing of 1,2,4-trichlorobenzene and Hg2+

Two novel zinc(II) phosphonates, [Zn(H4L)]·2H2O (1) and [Zn(H4L)(2,2′-biim)] (2) (2,2′-biim = 2,2′-biimidazole), were synthesized based on (2,4,6-trimethylbenzene-1,3,5-triyl) tris(methylene) triphosphonic acid (H6L), via hydrothermal techniques. Structural characterization was conducted using single-crystal X-ray diffraction analyses, X-ray powder diffraction analyses (PXRD), FT–IR spectroscopy, thermogravimetric analyses (TGA) and elemental analyses (EA). Compound 1 was a 2D layered structure that exhibited high selectivity and sensitivity as a luminescent probe for the detection of polychlorinated benzene, with a very low detection limit of 8.20 × 10−7 M. Compound 2 possessed a one-dimensional chain structure that transformed into a 2D supramolecular structure through hydrogen bonding interactions. The excellent Lewis base recognition sites in 2 facilitated high sensitivity toward Hg2+ ions, with a low detection limit of 5.30 × 10−7 M. The test paper experiment showed that 2 could be made into the test paper to quickly detect Hg2+ by naked eye. Meanwhile, the probable sensing mechanisms were also discussed in this paper.

High Catalytic Efficiency of a Layered Coordination Polymer to Remove Simultaneous Sulfur and Nitrogen Compounds from Fuels

An ionic lamellar coordination polymer based on a flexible triphosphonic acid linker, [Gd(H4nmp)(H2O)2]Cl2 H2O (1) (H6nmp stands for nitrilo(trimethylphosphonic) acid), presents high efficiency to remove sulfur and nitrogen pollutant compounds from model diesel. Its oxidative catalytic performance was investigated using single sulfur (1-BT, DBT, 4-MDBT and 4,6-DMDBT, 2350 ppm of S) and nitrogen (indole and quinolone, 400 ppm of N) model diesels and further, using multicomponent S/N model diesel. Different methodologies of preparation followed (microwave, one-pot, hydrothermal) originated small morphological differences that did not influenced the catalytic performance of catalyst. Complete desulfurization and denitrogenation were achieved after 2 h using single model diesels, an ionic liquid as extraction solvent ([BMIM]PF6) and H2O2 as oxidant. Simultaneous desulfurization and denitrogenation processes revealed that the nitrogen compounds are more easily removed from the diesel phase to the [BMIM]PF6 phase and consequently, faster oxidized than the sulfur compounds. The lamellar catalyst showed a high recycle capacity for desulfurization. The reusability of the diesel/H2O2/[BMIM]PF6 system catalyzed by lamellar catalyst was more efficient for denitrogenation than for desulfurization process using a multicomponent model diesel. This behavior is not associated with the catalyst performance but it is mainly due to the saturation of S/N compounds in the extraction phase.

Novel nanocomposites based on epoxy resin and modified magnesium hydroxide: Focus on flame retardancy and mechanical properties

In this work, a novel multifunctional organic‐inorganic hybrid flame agent (AM‐MEL) was prepared from magnesium hydroxide nanosheets decorated by nitrilotrimethylene triphosphonic acid and melamine. Then, an intrinsic flame‐retardant epoxy resin (EP) was prepared by covalently incorporating AM‐MEL nanoparticles. Meanwhile, ammonium polyphosphate (APP) was added into EP to form an intumescent flame retardant system with AM‐MEL. The chemical structure of AM‐MEL was characterized by Fourier transform infrared spectra, X‐ray photoelectron spectroscopy, and scanning electron microscopy. With the incorporation of 5 wt% AM‐MEL and 15 wt% APP, EP/AM‐MEL/APP could reach a limiting oxygen index value of 32.0% and achieve UL‐94 V‐0 rating, along with 88.0%, 70.0%, 81.5%, and 87.3% decrease in the peak heat release rate, total heat release, total smoke production, and the peak CO production rate, respectively, with respect to that of pure EP. The mechanisms of its flame retardant and smoke suppression were investigated.

Structural Tuning and Sensitization of Uranyl Phosphonates by Incorporation of Countercations into the Framework.

By the introduction of terephthalic acid, tetramethylammonium chloride, and Zn2+ ions, three new uranyl triphosphonates with varying crystal structures, namely, [H3O][(UO2)2(HL)]·H2O (1), [NMe4][(UO2)2(HL)(H2O)]·H2O (2), and [(UO2)3Zn(H2L)2(H2O)2]·3H2O (3), where H6L = benzene-1,3,5-triyltris(methylene) triphosphonic acid, have been successfully synthesized and characterized by means of powder and single crystal XRD, IR, EA, TGA, UV-vis, and luminescence. These three compounds all possess three-dimensional framework structures with hydrium, tetramethylammonium, and Zn2+ as the respective countercations. The uranium(VI) center luminescence of compounds 1 and 2 is completely quenched. However, the incorporation of Zn2+ into the matrix of uranyl phosphonate in the case of compound 3 results in the emerging of the typical intense vibronic emissions of U(VI), demonstrating that zinc phosphonate can behave as sensitizer of uranyl phosphonates. The quenching and sensitization mechanism were also discussed.

Magnesium doped Gallium Phosphonates Ga1–xMgx[H3+x(O3PCH2)3N] (x = 0, 0.20) and the Influence on Proton Conductivity

In our contribution to the development of new proton conductive coordination polymers (CPs) we focus on the impact of a partial replacement of Ga3+ by Mg2+. This approach should come along with the introduction of additional protons due to charge balances. In a first step we have synthesized an isostructural compound to the literature known compound AlH3P3N [H6P3N = nitrilotris(methylene)triphosphonic acid], where Al3+ is replaced by Ga3+, since all attempts to incorporate Mg2+ ions directly into AlH3P3N were not successful. The relative amount of Mg2+ and Ga3+ was established by EDX analysis. Rietveld refinement of the synchrotron data located the Ga3+ and Mg2+ ions on a split position, proving the disordered incorporation of the Mg2+ ions. Solid‐state NMR spectroscopy confirms a disordered protonation of the phosphonate groups as well and shows that all amine groups are protonated. In order to investigate the effect on the proton conductivity the compounds Ga[H3(O3PCH2)3N], denoted GaH3P3N as well as Ga0.80Mg0.20[H3.20(O3PCH2)3N], denoted GaMgH3.20P3N, were characterized by electrochemical impedance spectroscopy (EIS). Arrhenius behavior in the investigated temperature range (70–130 °C) was found for both compounds (activation energies of Ea = 0.15 eV for GaH3P3N and 0.17 eV for GaMgH3.20P3N). The GaMgH3.20P3N sample shows a reduced proton mobility (σ = 1.2 × 10–4 S·cm–1) of about one order of magnitude in comparison to GaH3P3N (σ = 1.0 × 10–3 S·cm–1).

Fabrication of New Uranyl Phosphonates by Varying Quaternary Ammonium Cation: Synthesis, Structure, Luminescent Properties, and Single-Crystal to Single-Crystal Transformation.

Four new uranyl triphosphonates, namely, [N(CH4)4][UO2(H3L)][H2O] (1), [(UO2)1.5(H3L)(H2O)1.5][H2O] (2), [NBu4][(UO2)3.5(H2L)2][(H2O)4.5] (3), and [(UO2)1.5(H3L)(H2O)2.5][(H2O)2.5] (4), where H6L = benzene-1,3,5-triyltris(methylene)triphosphonic acid, were obtained from a triphosphonate ligand in the presence of different quaternary ammonium cations. The structural characterization revealed that the introduction of quaternary ammonium cation had a major impact on the structure formation of uranyl phosphonates. Compound 1 possesses a three-dimensional anionic framework structure. Tetramethylammonium cations are accommodated in the channels, serving as counterions and structure directing agents. Compound 2 also displays a three-dimensional framework structure but is neutral, because the tetrapropylammonium cations are not involved in the crystal structure. Compound 3 has an intercalation structure; between the layers are the tetrabutylammonium cations, balancing the charge and strengthening the supramolecular structure with C-H···O interactions. No obvious uptake of N2 and CO2 could be observed for compound 2 due to the shrinkage of the framework and structural transformation. Compound 2 undergoes single-crystal to single-crystal transformation under vacuum, leading to the formation of compound 4, which possesses a two-dimensional layer structure. The photophysical properties of these compounds were also investigated.

Cobalt Phosphonates as Precatalysts for Water Oxidation: Role of Pore Size in Catalysis

We report a simple approach for the synthesis of cobalt phosphonate (CoOP) nanocages with two distinct types of pore diameters by utilizing a novel tetra-constituent assembly of CoCl2 ⋅6 H2 O, nitrilotris(methylene)triphosphonic acid (NMPA), F127 surfactant, and polyvinyl alcohol (PVA, co-surfactant). Transmission electron microscopy images revealed the formation of large nanocages in spheres (pore diameter: 20-60 nm) and the existence of narrow micro/mesopores (pore diameter: 1.5-5 nm) on their walls. Brunauer-Emmett-Teller adsorption/desorption experiments led to the observation of dual porosity and indicated that the contribution of micro/mesopores increased gradually with increasing concentration of PVA during synthesis from CoOP-0 to CoOP-15 (where the number gives the wt % of PVA used in CoOP synthesis). These materials acted as precatalysts for heterogeneous water oxidation at pH 13.9 (1 m KOH) and electrochemical studies revealed that the reactivity improved remarkably with increasing contribution of narrow micro/mesopores. Among these catalysts, the best catalyst (CoOP-15) exhibited an overpotential of 380 mV and turnover frequency of 1.6×10-2 s-1 . The improvement of reactivity was due to significant enhancement of electrochemically accessible surface area with increasing contribution of narrow micro/mesopores, which facilitated contact between the catalyst and water molecules by improving mass transport inside the nanomaterials. Hence, this study suggests narrow micro/mesopores are beneficial towards enhancement of water oxidation catalysis.

Highly Ordered Mesostructured Vanadium Phosphonate toward Electrode Materials for Lithium-Ion Batteries.

Highly ordered mesostructured vanadium phosphonates (VP) have been synthesized in the presence of cetyltrimethylammonium bromide (CTAB) as a structure-directing agent. Nitrilotris(methylene)triphosphonic acid (NMPA) and (ammonium/sodium) metavanadate (NH4 VO3 /NaVO3 ) have been used for the construction of pore walls. The CTAB templates are removed from the materials by an extraction process without destroying the parent mesostructure. The formation mechanism for the ordered mesoporous structure and its impact on electrochemical application in lithium ion batteries (LIBs) are explained by considering the structural and electrochemical stability of the framework. The results demonstrate that the counter cations (NH4+ /Na+ ) of the metavanadate precursors have a crucial role in stabilizing the mesoporous structure of the mesoporous VP materials. Mesoporous VP materials with highly ordered structure have great applicability as high-performance electrode materials in LIBs due to the advantages of their large contact area with electrolyte and short transport paths for lithium ions. Mesoporous VP electrodes exhibit high reversible specific capacity with superb cycling stability (100 cycles) and excellent retention of capacity (92 %).

A Lamellar Coordination Polymer with Remarkable Catalytic Activity.

A positively charged lamellar coordination polymer based on a flexible triphosphonic acid linker is reported. [Gd(H4 nmp)(H2 O)2 ]Cl⋅2 H2 O (1) [H6 nmp=nitrilotris(methylenephosphonic acid)] was obtained by a one-pot approach by using water as a green solvent and by forcing the inclusion of additional acid sites by employing HCl in the synthesis. Compound 1 acts as a versatile heterogeneous acid catalyst with outstanding activity in organic reactions such as alcoholysis of styrene oxide, acetalization of benzaldehyde and cyclohexanaldehyde and ketalization of cyclohexanone. For all reaction systems, very high conversions were reached (92-97 %) in only 15-30 min under mild conditions (35 °C, atmospheric pressure). The coordination polymer exhibits a protonic conductivity of 1.23×10(-5) S cm(-1) at 98 % relative humidity and 40 °C.

Phosphonate-Derived Nanoporous Metal Phosphates and Their Superior Energy Storage Application.

Nanoporous nickel, aluminum, and zirconium phosphates (hereafter, abbreviated as NiP, AlP, and ZrP, respectively) with high surface areas and controlled morphology and crystallinity have been synthesized through simple calcination of the corresponding phosphonates. For the preparation of phosphonate materials, nitrilotris(methylene)triphosphonic acid (NMPA) is used as phosphorus source. The organic component in the phosphonate materials is thermally removed to form nanoporous structures in the final phosphate materials. The formation mechanism of nanoporous structures, as well as the effect of applied calcination temperatures on the morphology and crystallinity of the final phosphate materials, is carefully discussed. Especially, nanoporous NiP materials have a spherical morphology with a high surface area and can have great applicability as an electrode material for supercapacitors. It has been found that there is a critical effect of particle sizes, surface areas, and the crystallinities of NiP materials toward electrochemical behavior. Our nanoporous NiP material has superior specific capacitance, as compared to various phosphate nanomaterials reported previously. Excellent retention capacity of 97% is realized even after 1000 cycles, which can be ascribed to its high structural stability.

Layer‐by‐layer deposition of nitrilotris(methylene)triphosphonic acid and Zr(IV): an XPS, ToF‐SIMS, ellipsometry, and AFM study

Layer‐by‐layer assemblies consisting of alternating layers of nitrilotris(methylene)triphosphonic acid (NTMP), a polyfunctional corrosion inhibitor, and zirconium(IV) were prepared on alumina. In particular, a nine‐layer (NTMP/Zr(IV))4NTMP stack could be constructed at room temperature, which showed a steady increase in film thickness throughout its growth by spectroscopic ellipsometry up to a final thickness of 1.79 ± 0.04 nm. At higher temperature (70 °C), even a two‐layer NTMP/Zr(IV) assembly could not be prepared because of etching of the alumina substrate by the heated Zr(IV) solution. XPS characterization of the layer‐by‐layer assembly showed a saw tooth pattern in the nitrogen, phosphorus, and zirconium signals, where the modest increases and decreases in these signals corresponded to the expected deposition and perhaps removal of NTMP and Zr(IV). Time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS) confirmed the attachment of the NTMP molecule to the surface through PO−, PO2−, PO3−, and CN− signals. Increasing attenuation of the Al signal from the substrate after deposition of each layer was observed by both XPS and ToF‐SIMS. Essentially complete etching of the alumina by the heated Zr(IV) solution was confirmed by spectroscopic ellipsometry, XPS, and ToF‐SIMS. Atomic force microscopy revealed that all the films were smooth with Rq roughness values less than 0.5 nm. Copyright © 2015 John Wiley & Sons, Ltd.

Mesoporous Iron Phosphonate Electrodes with Crystalline Frameworks for Lithium-Ion Batteries

A new family of mesoporous iron phosphonate (FeP) materials has been prepared through cooperative assembly of cetyltrimethylammonium bromide (CTAB), iron nitrate, and nitrilotris(methylene)triphosphonic acid (NMPA). CTAB is used as a structure directing agent, while the other two chemicals are used as precursors for the formation of pore walls. An extraction procedure is employed to remove the template without damaging the as-prepared ordered mesostructure. The obtained mesoporous FeP materials are well characterized by low angle X-ray diffraction (XRD), N2 adsorption isotherms, and transmission electron microscopy. The mesostructural ordering of the obtained materials strongly depends on the synthetic conditions. The morphology and the crystallinity of the pore walls are investigated by scanning electron microscopy and wide-angle XRD measurements, respectively. It is revealed that the FeP framework is crystallized in the tetragonal crystal phase (I41/amd), according to the Rietveld refinement of the XRD ...

Fluorine plasma treatment of bare and nitrilotris(methylene)triphosphonic acid (NP) protected aluminum: an XPS and ToF-SIMS study

Nitrilotris(methylene)triphosphonic acid (NP) is a technologically important molecule that has been used for years as a corrosion inhibitor and/or adhesion promoter on aluminum and other metal surfaces. However, to the best of our knowledge, the detailed surface characterization of NP adsorbed on aluminum, or on any other surface, has not been reported. Herein, we report an X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry (ToF-SIMS) analysis of a series of untreated and NP-coated aluminum substrates that were exposed to the downstream products of a fluoroalkane + oxygen plasma for different amounts of time (from 0 to 20 s). As indicated by P 2p, N 1s, Al 2p, O 1s, and F 1s narrow scans, even a 4-s plasma treatment significantly damages the NP protective layer and converts the native aluminum oxide into aluminum oxyfluoride. Heat treatment of the fluorine plasma-treated samples in the air substantially converts the aluminum oxyfluoride back to aluminum oxide, while similar heating under vacuum results in little change to the materials. A slow loss of fluorine from the samples occurs over the course of weeks when they are stored in the air. A ToF-SIMS analysis reveals sets of signals that are consistent with no surface treatment, NP treatment, or fluorine plasma treatment. A principal component analysis of the negative ion ToF-SIMS spectra from the samples shows the expected differentiation of the samples. Copyright © 2014 John Wiley & Sons, Ltd.

Layered Metal–Organic Frameworks Based on Octahedral Lanthanides and a Phosphonate Linker: Control of Crystal Size

The hydrothermal reaction between lanthanide salts and residues of (benzene-1,3,5-triyltris(methylene))triphosphonic acid (H6bmt) promotes the formation of a new series of isotypical layered lanthanide–organic frameworks (LnOFs), [Ln2(H3bmt)2]·H2O [where Ln3+ = Eu3+ (1), Gd3+ (2), Tb3+ (3), Dy3+ (4), Ho3+ (5), Er3+ (6), Tm3+ (7), and Yb3+ (8)]. The crystal structure was unveiled from powder X-ray diffraction data (both laboratory and synchrotron) in tandem with other characterization techniques (namely thermogravimetry, thermodiffractometry, vibrational spectroscopy, and elemental analysis). It is shown that the lanthanide contraction leads, on average, to a reduction of the average crystallite size, up to the nanometer scale in the case of compound 8. The unique structural features of the ∞2[Ln2(H3bmt)2] layers are discussed in detail, in particular, the six-coordination environment of the lanthanide cations and its topological relationship with the formation of the first 5,5L4 binodal network based on chelating phosphonate groups.