Search Results (89)

Neutron-capture products, such as molybdenum (Mo) isotopes, are an important tool that cosmochemists use to constrain the stellar precursors of the Solar System and, potentially, the origin of life on Earth. Using high-precision Mo isotope data from meteorites and terrestrial samples, studies have attempted to reconstruct Earth’s formation by linking its composition to material sourced from various heliocentric distances. Debate, however, persists about the nature of Earth’s late-stage building blocks that accreted around the time the Moon formed and whether they delivered life-essential elements (i.e., carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfur; CHNOPS), which are presumed to be more prevalent in the outer Solar System. Initially, it was proposed that the Moon-forming event involved the addition of material from both the inner and outer Solar System, thereby providing a mechanism for the delivery of a significant portion of life-bearing elements late in Earth’s formation. Recent advancements in analytical chemistry and their application to a wider range of samples than previously studied, however, led to a revised constraint: the Moon-forming event was dominated by inner Solar System material that was less enriched in CHNOPS, thereby relaxing the requirement for the delivery of a consequential amount of life-bearing elements late in Earth’s formation. A review of analytical approaches and findings is presented here to highlight the utility of neutron-capture products in constraining the origin of life on Earth. Full article

This study investigates the influence of various manganese sources—specifically MnCO₃, Mn₃O₄, and MnO₂—on the performance of lithium manganese iron phosphate (LMFP) synthesized through a combined spray-drying and chemical vapor deposition (CVD) strategy. The synthesis protocol involved the initial formation of a precursor through the co-sintering of manganese, phosphorus, iron, and dopant sources via CVD, followed by secondary spray-drying and carbon thermal reduction with Li₂CO₃ and carbon additives. Morphological analysis via Scanning Electron Microscopy (SEM) and laser diffraction indicates that Mn₃O₄-derived LMFP possesses highly spherical secondary structures comprising well-crystallized, uniformly distributed primary particles. Elemental mapping via Energy Dispersive Spectroscopy (EDS) confirms a homogeneous distribution of stoichiometric elements without localized segregation, alongside the successful lattice integration of dopants. In contrast, the MnCO₃-derived samples exhibited deleterious carbon accumulation on the primary particle surfaces. Consequently, the Mn₃O₄-based LMFP demonstrated superior electrochemical kinetics, delivering a remarkable initial discharge capacity of 148.9 mAh g⁻¹ at 1C, with an exceptional capacity retention of 97.9% after 100 cycles. These findings underscore the critical role of precursor selection in optimizing the interfacial and bulk properties of high-performance LMFP cathodes. Full article

Mevalonate is a biochemical precursor to a wide range of isoprenoids. Because the mevalonate pathway uses three moles of acetyl–CoA, native pathways which metabolize acetyl–CoA, including citrate synthase, strongly compete with mevalonate synthesis. Our hypothesis is that modifications in citrate synthase, with the aim of reducing this enzyme’s activity, can result in increased mevalonate. Previous research has demonstrated that citrate synthase variants can increase generation of acetyl–CoA-derived products from glucose, but research has not evaluated citrate synthase variants with other common carbon sources like xylose and glycerol. Using five variant strains with chromosomal modifications of citrate synthase, we first compared the growth of these variants with wild-type Escherichia coli on glucose, xylose, or glycerol. In general, any particular modification in citrate synthase (GltA) led to the greatest effect on growth rate in glucose-grown cells. Because the GltA[Y87N D101D* P208L] and GltA[A267T] variants showed the greatest effect on growth using glycerol, we selected these two variants to study the formation of mevalonate from glycerol by E. coli with an introduced mevalonate pathway. Controlled batch processes at the 1.3 L scale demonstrated significantly increased mevalonate production in variants compared to the wild-type background, with the GltA[A267T] attaining 7.3 g/L mevalonate in 16.5 h from 30 g/L glycerol. Nitrogen-limited or phosphorus-limited fed-batch processes using the GltA[A267T] variant performed similarly, and generated over 12 g/L mevalonate in 24–32 h at a yield of 0.24 g/g. This study demonstrates that GltA variants offer a means to generate acetyl–CoA-derived products from glycerol. Full article

In the present work, we describe the synthesis of a new heterocyclic derivative, 2-(naphthalen-1-yl)-2,3,5,6-tetrahydro-1H-isoquinolino[8,1,2-hij]quinazoline 1, using the reaction between the aminal 1,3,6,8-tetraazatricyclo[4.4.1.1^3,8]dodecane 2 (TATD) and 1-naphthylamine 3 as the first scaffold of a four-step linear synthetic route. In the first step, a condensation catalyzed by acetic acid in 96% ethanol was carried out, leading to the formation of the intermediate 3-(naphthalen-1-yl)-1,2,3,4-tetrahydrobenzo[h]quinazoline 4. Subsequently, this intermediate was acylated with 2-chloroacetyl chloride in the presence of triethylamine and under an inert atmosphere, obtaining the compound 2-chloro-1-(3-(naphthalen-1-yl)-3,4-dihydrobenzo[h]quinazolin-1(2H)-yl)ethan-1-one 5. In the third step, an intramolecular Friedel–Crafts cyclization was carried out using aluminum trichloride as a catalyst, yielding 2-(naphthalen-1-yl)-1,2,3,6-tetrahydro-5H-isoquinolino[8,1,2-hij]quinazolin-5-one 6. Finally, the reduction of this lactam with phosphorus pentachloride and sodium borohydride under anhydrous conditions led to the further closure of the polycyclic system, yielding the final product 1. The proposed route demonstrates the feasibility of using TATD 2 as a versatile precursor for constructing condensed heterocyclic systems of structural interest and potential relevance in advanced organic synthesis. Full article

This work supports the circular economy and sustainable material by facilitating the creation of low-carbon materials with enhanced elimination of nutrients from wastewater, thereby assisting in preventing eutrophication. Porous geopolymers, owing to their distinctive pore structure and numerous superior properties, including noise reduction and thermal insulation, have a wide range of potential applications in the building sector, chemical industry, and water treatment. Developing low-carbon-footprint porous geopolymer materials is an important step toward creating multipurpose lightweight materials that can serve as structural materials and, at the same time, as adsorbents. In this study, it was revealed that the porous material created during the hydrothermal synthesis of (lime–Portland cement-based aerated composition), by replacement of sand with wood biomass bottom ash (WBA), can be used as porous aggregates (PA) for adsorbent development. PA was produced with an apparent porosity of 65%, a density of 610 kg/m³, and a compressive strength of 2.0 MPa. The effectiveness of employing an air-entraining additive (AEA) and creating PA in geopolymers was tested. A different-molarity activator was used, and wood biomass fly ash (WFA) and metakaolin (MK) waste were used as precursors for the synthesis of porous geopolymers. Using an air-entraining admixture in geopolymers allows for the production of lightweight geopolymers with densities up to 1400 kg/m³, compressive strengths up to 8.0 Mpa, and apparent porosities up to 38.4%. Such properties, together with their low cost, offer good prospects for geopolymers in the construction industry. By utilizing PA in the geopolymer composition, a lightweight geopolymer (GPA) with a density of 985 kg/m³ and a compressive strength of 3.9 Mpa, with 42.0% apparent porosity, was obtained. The materials effectively removed phosphorus from biologically treated wastewater: PA had an efficiency of up to 82.5%, the geopolymer with AEA had an efficiency of up to 88.4%, and GPA had an efficiency of up to 97%. The created GPA enhances the adsorbent’s sorption capacity, resulting in extremely high phosphorus uptake efficiency. Full article

Wastewater-based microalgal cultivation enables coupling environmental remediation with the production of sustainable, value-added biomass. In this study, Euglena gracilis was cultivated under non-axenic conditions in a 2% anaerobically digested livestock wastewater (LSWW)-based medium to enhance biomass accumulation, paramylon storage, and biodiesel precursor production, while simultaneously removing residual nitrogen and phosphorus. The LSWW medium was strongly phosphate-limited relative to ammoniacal nitrogen (N:P mass ratio ~39:1), which constrained growth. Adjustment of the N:P ratio to ~10:1 by NaH₂PO₄ supplementation, together with MgSO₄·7H₂O addition, significantly enhanced biomass production, whereas trace metals and CaCl₂ provided minimal benefit. Cultivation at an initial pH of 3 resulted in substantially higher biomass accumulation than at pH 7 under xenic conditions. Under these optimized conditions, total phosphate and ammonia were efficiently removed, decreasing from 5.27 to 0.009 mg/L (99.8%) and from 57.40 to 2.11 mg/L (96.3%), respectively. Although paramylon accumulation was low in LSWW alone (~4% dry weight), short-term ethanol supplementation (0.095%, v/v, 24 h) enhanced paramylon content to ~20% dry weight. Subsequent anaerobic treatment further enhanced lipid conversion, increasing fatty acid methyl ester (FAME) content to ~45% dry weight. Collectively, low-pH non-axenic cultivation of E. gracilis in LSWW, combined with minimal nutrient supplementation, provides an integrated platform for enhanced biomass, paramylon, and biodiesel precursor production with efficient nutrient removal. Full article

Porous highly cross-linked polymer (PIP) was synthesized by a polycondensation reaction between hexachlorocyclotriphosphazene and piperazine. The obtained polymer has a surface area of 76.9 m²/g and a mesoporous structure. After carbonization, the obtained product (PIP-C) has a surface area of 177 m²/g. The obtained carbon product contained nitrogen and phosphorus heteroatoms, which leads to a higher specific capacitance (155.6 F/g) and catalytical activity in the electroreduction of oxygen (15.9 A/g). This work shows the possibility of the use of such porous phosphazene polymers as precursors for heteroatom-doped carbon materials, which might be used in electrochemical devices like electrodes for supercapacitors or metal-free electrocatalysts in fuel cells. Full article

Modulating the electronic structure and surface properties of graphitic carbon nitride (g-C₃N₄) by chemically phosphorus doping is an effective strategy for improving its photocatalytic performance. However, in order to benefit from practical applications, the cost-effectiveness, efficiency, and optimization of the doping level need to be investigated further. Herein, we report a structural doping of P into g-C₃N₄ by in situ polymerization of the mixture of dicyandiamide (DCDA) and phosphorus pentoxide (P₂O₅). As an alternative to previous studies that used complex organic phosphorus precursors or post-treatment strategies, this work proposed a one-pot thermal polycondensation method that is low-cost, scalable, and enables controlled phosphorus substitutions at carbon sites of the g-C₃N₄ heptazine structure. Most of the structural features of g-C₃N₄ were well retained after doping, but the electronic structures and light harvesting capacity had been effectively altered, which provided not only a much better charge separation but also an improvement in photocatalytic activity toward H₂ evolution under irradiation of a simulated sunlight. The optimized sample with P-doping content of 9.35 at.% (0.5PGCN) exhibited an excellent photocatalytic performance toward H₂ evolution, which is over 5 times higher than that of bulk g-C₃N₄. This work demonstrates a facile one-step in situ route for producing high-yield photocatalysts using low-cost commercial precursors, offering practical starting materials for studies in solar cells, polymer batteries, and photocatalytic applications. Full article

Tetranuclear rhodium carbonyl clusters are vital catalytic precursors; yet derivatives featuring bidentate phosphines are less common, due to the propensity for cluster fragmentation during synthesis. This study reports the successful isolation of five new heteroleptic species by reacting Rh₄(CO)₁₂ with various bidentate diphosphines under homogeneous conditions and at room temperature, namely the mono-substituted Rh₄(CO)₁₀(dppe) (1) and Rh₄(CO)₁₀(dppb) (3), the rare bis-substituted derivative Rh₄(CO)₈(dppe)₂ (2), and the two unique dimeric assemblies {Rh₄(CO)₁₀(dpp-hexane)}₂ (4) and {Rh₄(CO)₁₀(trans-dppe)}₂ (5). The tetrahedral Rh₄ core of the cluster precursor was preserved in all cases. The new compounds were characterized via infrared (IR) spectroscopy and single-crystal X-ray diffraction (SC-XRD). Furthermore, variable-temperature (VT) ³¹P{¹H} NMR spectroscopy elucidated the dynamic behavior of the phosphorus atoms. This work reports a robust methodology for accessing stable, low-nuclearity rhodium phosphine clusters with tunable properties. Full article

Li₃PO₄ is an ideal precursor for synthesizing high-performance LiFePO₄, as it simultaneously provides lithium and phosphorus sources. Extremely low solubility of Li₃PO₄ enables efficient lithium recovery from low-concentration Li-rich brine by reactive crystallization. A focused beam reflectance measurement (FBRM) system was employed to monitor the key optimization parameters for Li₃PO₄ crystallization, supersolubility, and metastable zone widths (MSZWs). The optimized process parameters were determined by systematically investigating the effects of operating conditions. Additionally, prediction of supersolubility and MSZWs was accomplished with theoretical models. Results demonstrate that both supersolubility and MSZWs exhibit a pronounced negative correlation with temperature. Supersolubility decreased sharply when LiCl concentration exceeded 5 mol·L⁻¹ or Na₃PO₄ concentration surpassed 0.8 mol·L⁻¹. Conversely, it increased exponentially with Na₃PO₄ feeding rate. The effect of impurity (NaCl/KCl) was non-monotonic, initially increasing and then decreasing supersolubility and MSZWs. Among these, Na₂B₄O₇ most significantly enhanced both parameters, followed by Na₂SO₄. The supersolubility data were well-fitted by an empirical equation (R² > 0.99). For MSZWs prediction, the self-consistent Nývlt-like model (R² > 0.9883) and the modified Sangwal’s model (R² > 0.994) achieved superior performance. Collectively, these findings establish a theoretical basis for optimizing lithium recovery via Li₃PO₄ crystallization, facilitating more efficient and sustainable production of high-purity lithium products. Full article

The present study investigates the influence of alternating current (AC) frequency on the formation and properties of calcium-, phosphorus-, and selenium-containing micro-arc oxidation (MAO) coatings on high-purity magnesium. Coatings were produced at 50–400 Hz in a phytic-acid-based electrolyte containing Ca, P, and Se precursors, and their structure, chemistry, and functional performance were systematically evaluated. Surface morphology, analyzed by SEM and optical profilometry, revealed frequency-dependent features: lower frequencies (50 Hz) promoted thicker, rougher coatings with extensive cracking, whereas intermediate frequencies (100–200 Hz) yielded more uniform, porous surfaces. The CaPSe_100 specimen exhibited the most homogeneous topography (lowest S10z and SD) combined with the highest porosity (28.4%), strong hydrophilicity, and the greatest selenium incorporation (1.30 wt.%). Hydrogen evolution testing in Hanks’ solution demonstrated a drastic improvement in corrosion resistance following MAO treatment: the degradation rate of bare Mg (5.50 mm/year) was reduced to 0.012 mm/year for the CaPSe_100 coating—well below the clinical tolerance threshold for biodegradable implants. This outstanding performance is attributed to the synergistic effect of a uniform oxide barrier, optimized porosity, and homogeneous surface morphology. The results highlight the potential of frequency-controlled AC-MAO processing as a route to tailor magnesium surfaces for multifunctional, corrosion-resistant biomedical applications. Full article

Water pollution caused by synthetic dyes is a major environmental concern due to their stability, toxicity, and resistance to conventional wastewater treatments. This study presents a sustainable approach for synthesizing zinc oxide (ZnO) nanoparticles using artichoke biomass (waste) as a green precursor and enhancing their visible light photocatalytic activity through phosphorus doping. ZnO nanoparticles were successfully synthesized via a simple green route and doped with 3–6% phosphorus using NH₄H₂PO₄. The structural, morphological, and optical properties of the resulting P-ZnO were characterized by XRD, SEM/EDX, TEM, FTIR, and UV-Vis spectroscopy. (6 wt%) Phosphorus doping effectively reduced the band gap from 3.06 eV to 2.95 eV, extended light absorption into the visible range, and improved electron–hole separation, resulting in enhanced photocatalytic performance. The P-ZnO nanoparticles were evaluated for methylene blue (MB) degradation under visible light in a photo-Fenton-like process, with H₂O₂ as an oxidant. The degradation efficiency reached 87.05% with 6% P-ZnO and further increased to 92.35% upon addition of H₂O₂. Durability and reusability tests demonstrated that the 6% P-ZnO catalyst maintained its activity and structural integrity over four consecutive cycles, indicating negligible loss of efficiency and excellent resistance to surface poisoning. The photocatalytic activity was strongly impacted by the quantity of catalyst, solution pH, and initial dye levels, with optimal performance at 0.3 g/L catalyst loading, pH 3, and lower MB concentrations. Full article

Morels are a rare edible and medicinal fungus. A major factor contributing to difficulties with their continuous cropping is alteration in soil microbial communities. Pseudomonas putida is a key microorganism in morel cultivation soils; it has garnered significant attention due to its ability to degrade 1-aminocyclopropane-1-carboxylic acid (ACC), a precursor of ethylene. However, the interaction between Pseudomonas putida and morels remains unclear. This study evaluated the growth-promoting potential of P. putida KT2440 by measuring the casing soil ACC content and assessing its ACC utilization capacity. Metagenomic sequencing was performed to assess the changes in soil microbial composition and function. The results indicated that ACC accumulated in the soil following morel cultivation and that P. putida KT2440 was capable of utilizing ACC as its sole nitrogen source for growth on plates. Inoculation enhanced the depletion of available nitrogen, phosphorus, and potassium; increased bacterial diversity; improved the stability of the soil microbial community; and caused the mycelium of morels to grow earlier. These processes occurred along with a decline in the abundance of the Streptomyces genus. Furthermore, a positive correlation was identified between the abundance of P. putida and ACC deaminase activity in the soil. Overall, this study examined the role of Pseudomonas putida inoculation in modulating the soil microbial community and metabolic processes within casing soil during Morchella sextelata cultivation. The findings indicate that P. putida inoculation promotes Morchella growth through ACC decomposition and microbial restructuring, offering a potential strategy for mitigating ethylene-related suppression in continuous cropping systems. Full article

Indium phosphide (InP) is a promising photoactive material for solar-driven hydrogen production owing to its optimal bandgap, high carrier mobility, and broad solar absorption. However, conventional InP fabrication relies on costly wafers and toxic precursors, limiting its scalability and sustainability. Here, we demonstrate a simple and environmentally friendly route to synthesize n-type InP thin-film photoanodes by phosphidating indium films prepared via doctor blade coating on ITO substrates, using NaH₂PO₂ as a phosphorus source. Structural and spectroscopic analyses (XRD, Raman, XPS, PL) confirmed the successful formation of crystalline InP with optimum quality at 425 °C. Photoelectrochemical measurements revealed a significant photocurrent density of 1.8 mA·cm⁻² under AM 1.5 illumination, with extended photoresponse into the near-infrared region. Mott–Schottky and EIS analyses indicated efficient charge separation, low transfer resistance, and unintentional n-type doping due to Sn diffusion from the ITO substrate. This facile and green synthesis route not only provides a scalable approach to III–V semiconductors but also highlights InP thin films as cost-effective and efficient photoanodes for sustainable solar hydrogen generation. Full article

Developing sustainable and high-performance sorbents for efficient CO₂ capture is essential for mitigating climate change and reducing industrial emissions. In this study, phosphorus-doped porous carbons (LPSP-T) were synthesized via a one-step activation–doping strategy using lotus petiole biomass as a precursor and sodium phytate as a dual-function activating and phosphorus-doping agent. The simultaneous activation and phosphorus incorporation at various temperatures (650–850 °C) under a nitrogen atmosphere produced carbons with tailored textural properties and surface functionalities. Among them, LPSP-700 exhibited the highest specific surface area (525 m²/g) and a hierarchical porous structure, with abundant narrow micropores (<1 nm) and phosphorus-containing surface groups that synergistically enhanced CO₂ capture performance. The introduction of P functionalities not only improved the surface polarity and binding affinity toward CO₂ but also promoted the formation of a well-connected pore network. As a result, LPSP-700 delivered a CO₂ uptake of 2.51 mmol/g at 25 °C and 1 bar (3.34 mmol/g at 0 °C), along with a high CO₂/N₂ selectivity, fast CO₂ adsorption kinetics and moderate isosteric heat of adsorption (Q_st). Furthermore, the dynamic CO₂ adsorption capacity (0.81 mmol/g) was validated by breakthrough experiments, and cyclic adsorption–desorption tests revealed excellent stability with negligible loss in performance over five cycles. Correlation analysis revealed pores < 2.02 nm as the dominant contributors to CO₂ uptake. Overall, this work highlights sodium phytate as an effective dual-role agent for simultaneous activation and phosphorus doping and validates LPSP-700 as a sustainable and high-performance sorbent for CO₂ capture under post-combustion conditions. Full article