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Differences in phosphorus biogeochemistry and mediating microorganisms in the matrix and macropores
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Ionic conductivity of bias sputtered lithium phosphorus oxy-nitride thin films
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Spin diffusion in the Phosphorus-31 NMR relaxation in a layered crystalline α-Sn(IV) phosphate contaminated by paramagnetic impurities
The study of a layered crystalline Sn(IV) phosphate by solid-state NMR has demonstrated that the 31 P T 1 relaxation of phosphate groups, dependent on spinning rate is completely controlled by the limited spin diffusion to paramagnetic ions found by EPR. The spin-diffusion constant, D(SD), was estimated as 2.04 10 –14 cm 2 s –1 . Finally, the conclusion was supported by the 31 P T 1 time measurements in zirconium phosphate 1–1, also showing paramagnetic ions and in diamagnetic compound (NH 4 ) 2 HPO 4 .
Auxenochlorella protothecoides populations adapted to low phosphate conditions accumulated more non-phosphorus glycerolipids and biomass than wild type progenitors
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Room temperature decomposition of dimethyl methylphosphonate on cuprous oxide yields atomic phosphorus
Organophosphorus compounds have a wide range of reactivity depending on the coordination and oxidation state of the P atom. Due to their toxicity, certain organophosphonates are used as pesticides, herbicides, and, notoriously, as chemical nerve agents. The organophosphonate decomposition mechanism depends strongly on the substrate material, which motivates careful analysis of a range of potential materials for decontamination and sensing applications. Here, we present a study of the decomposition of dimethyl methylphosphonate (DMMP), a simulant molecule for the nerve agent sarin, on polycrystalline cuprous oxide surfaces (Cu 2 O). We use ambient pressure X-ray photoelectron spectroscopy (APXPS) and near-edge X-ray absorption fine structure (NEXAFS) spectroscopy to monitor the pressure-dependent surface chemistry during exposure to DMMP vapor. At room temperature, we observe extensive degradation of DMMP, which includes the formation of reduced P products on the sample surface. We identify five unique P-containing species in the P 2p APXPS spectra, including atomic P and a surface-bound phosphinate [O=PH(OCH 3 )Osingle bondCu]. Here we propose a DMMP decomposition pathway whereby accumulation of this phosphinate species leads to an autocatalytic reaction on the Cu 2 O surface which yields reduced P species. After DMMP exposure, heating the Cu 2 O sample to 265°C leads to complete removal of all carbonaceous species and accumulation of a phosphate layer with stoichiometry similar to P 2 O 5 . These results introduce a new mechanism of room-temperature DMMP decomposition on metal oxides, which could be leveraged for the design of tailored metal oxide materials for catalyzing organophosphonate decomposition.
Phosphorus- and boron-doped hydrogenated amorphous silicon films prepared using vaporized liquid cyclopentasilane
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Effect of iron sulphate on the phosphorus speciation from agro-industrial sludge based and sewage sludge based compost
Highlights: • Composting of agro-industrial and waste water sewage sludge promoted organic P mineralization. • Mineralized P is mainly adsorbed/precipitated on calcium. • FeSO{sub 4} reduced organic P mineralization and its further adsorption/precipitation on calcium. - Abstract: Composting is considered a suitable process for organic waste management, providing stable products that can be safely utilized as fertilizers, but little is still known about the variation of phosphorous (P) extractability during the stabilization process. In this work, sequential chemical extraction (SCE) with increasing strength extractants (H{sub 2}O; 0.5 M NaHCO{sub 3} pH 8.5; 0.1 M NaOH, 1 M HCl) was applied for P speciation over 56 days of composting of either agro-industrial or urban wastewater sludge with green waste treated (AIC{sub Fe+}; SSC{sub Fe+}) or not (AIC{sub Fe−}; SSC{sub Fe−}) with FeSO{sub 4} (2% v/v). Composting strongly reduced the H{sub 2}O-P, promoting the organic-P (P{sub o}) mineralization from the labile fraction (H{sub 2}O + NaHCO{sub 3} 40%), in addition to the increases of NaHCO{sub 3}- and HCl-extractable inorganic-P (P{sub i}) in both AIC{sub Fe−} and SSC{sub Fe−} (+20% on average). The FeSO{sub 4} treatment did not negatively affect the process, reducing the P{sub o} mineralization during composting by increasing the NaOH-P, also protecting this fraction from fixation in the sparingly soluble fraction. The final P fractionation (%) was in AIC{sub Fe−}: NaOH (41) = NaHCO{sub 3} (38) > HCl (18) > H{sub 2}O (3); in AIC{sub Fe+}: NaOH (53) > NaHCO{sub 3} (24) = HCl (22) > H{sub 2}O (2); in SSC{sub Fe−}: NaOH (46) > NaHCO{sub 3} (29) > HCl (21) > H{sub 2}O (4) and in SSC{sub Fe+}: NaOH (66) > NaHCO{sub 3} (13) > HCl (20) > H{sub 2}O (1). Composting reduced the more easily leachable fraction (labile-P{sub o}), reducing the risk of P loss by increasing the long-term available P fraction (NaOH-P). This was enhanced by the FeSO{sub 4} addition. Further investigation into soil behaviour and plant availability of P from this source is needed.
Lipid accumulation in nitrogen and phosphorus-limited yeast is caused by less growth-related dilution
Oleaginous yeasts are used commercially to produce oleochemicals and hold potential also for biodiesel production. In response to nitrogen or phosphorous limitation, oleaginous yeasts accumulate lipids in the form of triacylglycerols. Previous work has investigated potential mechanisms by which nutrient limitation induces lipid biosynthesis without verifying whether lipid biosynthesis flux is actually enhanced. Here, in this work, we show, using 13C-glucose tracing, that in nitrogen or phosphorous limitation, lipid accumulation occurs without consistent increases in biosynthetic flux. Instead, the main driver of increased lipid pools is decreased growth-related dilution. This conclusion holds across two divergent oleaginous yeasts: Rhodotorula toruloides and Yarrowia lipolytica . Quantitative proteomics shows a substantial proteome reallocation in response to nitrogen and phosphorous limitation, with ribosomal proteins strongly downregulated, while lipid enzymes are preserved but not consistently upregulated in absolute quantity. Thus, nutrient limitation, rather than triggering greatly enhanced lipid synthesis, results in roughly sustained lipid enzyme levels and biosynthetic flux. Due to slower lipid dilution by cell division, this suffices to drive marked lipid accumulation.
Probing Phosphorus Solubility and Its Effect on Critical Temperature ( T c ) in the Helical Superconducting Magnet RbEuFe 4 As 4– x P x
RbEuFe 4 As 4 exhibits a rare combination of high-temperature superconductivity and noncollinear magnetism, originating from the FeAs and Eu layers, respectively. In order to fine-tune its superconducting and magnetic properties, we studied P-doped RbEuFe 4 As 4–x P x . To determine the value of x for which RbEuFe 4 As 4–x P x exists, members of the series have been synthesized in the form of relatively large-sized single crystals by a high-temperature flux growth technique using RbAs flux as well as polycrystalline powder by direct combination reactions between RbFe 2 As 2 and EuFe 2 As 2–x P x . The flux crystal growth reactions indicate that RbEuFe 4 As 4–x P x forms with the values of x ≤ 0.12, which is corroborated by the Rietveld refinement analysis on the products obtained from direct combination reactions. The solubility limit exists primarily due to the preferential site As(2) occupation by P in the RbEuFe 4 As 4 crystal structure. Finally, as x increases in RbEuFe 4 As 4–x P x , magnetization measurements reveal that the superconducting critical transition temperature (T c ) decreases, while the magnetic ordering temperature (T N ) remains almost unchanged in comparison to undoped RbEuFe 4 As 4 .
Phosphorus Enrichment as a New Composition in the Solid Electrolyte Interphase of High-Voltage Cathodes and Its Effects on Battery Cycling
Immersion of a solid into liquid often leads to the modification of both the structure and chemistry of surface of the solid, which subsequently affects the chemical and physical properties of the system. For the case of the rechargeable lithium ion battery, such a surface modification is termed as solid electrolyte interphase (SEI) layer, which has been perceived to play critical role for the stable operation of the batteries. However, the structure and chemical composition of SEI layer and its spatial distribution and dependence on the battery operating condition remain unclear. By using aberration corrected scanning transmission electron microscopy coupled with ultra-high sensitive energy dispersive x-ray spectroscopy, we probed the structure and chemistry of SEI layer on several high voltage cathodes. We show that layer-structured cathodes, when cycled at a high cut off voltage, can form a P-rich SEI layer on their surface, which is a direct evidence of Li-salt (LiPF6) decomposition. Our systematical investigations indicate such cathode/Li-salt side reaction shows strong dependence on structure of the cathode materials, operating voltage and temperature, indicating the feasibility of SEI engineering. These findings provide us valuable insights into the complex interface between the high-voltage cathode and the electrolyte.
Nonthermal Plasma-Synthesized Phosphorus–Boron co-Doped Si Nanocrystals: A New Approach to Nontoxic NIR-Emitters
We report on the successful creation of nonthermal plasma-synthesized phorphorus and boron co-doped Si nanocrystals (PB:Si NCs) with diameters ( D NC ) ranging from 2.9 to 7.3 nm. Peak photoluminescence (PL) emission energies for all PB:Si NC diameters are ca. 400-500 meV lower than the excitonic emission values in intrinsic Si NCs, which can be attributed to prevalent donor-acceptor (D-A) transitions within the co-doped system. This D-A transition model is further evidenced by PL lifetimes within the range of 40-80 us, faster than what is observed for intrinsic Si NCs. By reducing the level of confinement within PB:Si NCs (i.e., D NC > 4 nm), we are able to red-shift the near-infrared (NIR)-emitting D-A transitions to below the band gap of bulk Si (1.12 eV). We quantify the PL quantum yield (PLQY) for a range of DNC and show that the plasma method can achieve reasonably high PLQY values (12% for D NC = 2.9 nm), even without any optimization of the synthesis or surface chemistry. We posit that perfect charge compensation cannot explain these results and propose a model in which dominant n-type doping accounts for the observations. Furthermore, these results demonstrate that nonthermal plasma synthesis is a viable pathway for preparing PB:Si NCs featuring NIR sub-band gap D-A transitions with relatively high quantum yields. More generally, this study provides insight into how doping affects energy and charge transfer within quantum-confined systems.
Phosphorus Dendrimer Derived Solid Sorbents for CO 2 Capture from Post-Combustion Gas Streams
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Phosphorus Release and Speciation in Manganese(IV) Oxide and Zeolite-Amended Flooded Soils
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Speciation of Select f -Elements with Lipophilic Phosphorus Acids and Diglycol Amides in the ALSEP Backward-Extraction Regime
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