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2.
Luminescence ; 39(6): e4805, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38859619

RESUMEN

In this study, a chemiluminescence (CL) method was developed to determine diphenoxylate in tablets and human plasma. This is the first CL method proposed to determine diphenoxylate. Creating three-dimensional data caused the parallel factor analysis algorithm (PARAFAC) to be used for the first time in CL methods. The method is based on the fact that diphenoxylate enhances the weak CL produced in the reaction of Ru(phen)3 2+ and acidic Ce(IV), and the concentration of Ce(IV) solution has a different effect on the CL response of diphenoxylate and the blank plasma. The calibration curve was linear from 4.0 × 10-8 to 1.6 × 10-6 mol L-1 (R2 = 0.9954), and the detection limit was 1.3 × 10-8 mol L-1 (S/N = 3). The sampling rate was about 30 samples per hour, and the % RSD for 10 repeated measurements of 4 × 10-7 mol L-1 diphenoxylate was 5.4%. The interference effects of some ions, amino acids, and common additives were also investigated. The CL method was successfully used to determine diphenoxylate in tablets, and the results were statistically confirmed by the reference method. The proposed CL method and the PARAFAC algorithm were successfully used to determine the concentration of diphenoxylate in human blood plasma samples.


Asunto(s)
Mediciones Luminiscentes , Comprimidos , Humanos , Comprimidos/química , Mediciones Luminiscentes/métodos , Luminiscencia , Límite de Detección , Algoritmos , Oxalatos/química , Oxalatos/sangre , Análisis Factorial
3.
Waste Manag ; 183: 199-208, 2024 Jun 30.
Artículo en Inglés | MEDLINE | ID: mdl-38761484

RESUMEN

Recovering valuable resources from spent cathodes while minimizing secondary waste generation is emerging as an important objective for the future recycling of spent lithium-ion batteries, including lithium iron phosphate (LFP) batteries. This study proposes the use of oxalic acid leaching followed by ferrioxalate photolysis to separate and recover cathode active material elements from spent LFP batteries. The cathode active material can be rapidly dissolved at room temperature using appropriate quantities of oxalic acid and hydrogen peroxide, as determined through thermodynamic calculations. The dissolved ferrioxalate complex ion (Fe(C2O4)33-) is selectively precipitated through subsequent photolysis at room temperature. Depending on the initial concentration, the decomposition ratio can exceed 95 % within 1-4 h. Molecular mechanism analysis reveals that the decomposition of the Fe(C2O4)33- complex ion into water-insoluble FeC2O4·2H2O results in the precipitation of iron and the separation of metal elements. Lithium can be recovered as dihydrogen phosphates through filtration and water evaporation. No additional precipitant is needed and no other side products are generated during the process. Oxalic acid leaching followed by photolysis offers an environmentally friendly and efficient method for metal recovery from spent LFP cathodes. The photochemical process is a promising approach for reducing secondary waste generation in battery recycling.


Asunto(s)
Suministros de Energía Eléctrica , Compuestos Férricos , Litio , Fosfatos , Fotólisis , Reciclaje , Reciclaje/métodos , Litio/química , Fosfatos/química , Compuestos Férricos/química , Oxalatos/química , Electrodos , Ácido Oxálico/química , Hierro/química , Peróxido de Hidrógeno/química
4.
J Colloid Interface Sci ; 670: 297-310, 2024 Sep 15.
Artículo en Inglés | MEDLINE | ID: mdl-38763026

RESUMEN

Fenton/Fenton-like reaction induced chemical dynamic therapy (CDT) has been widely recognized in tumor therapy. Due to the low efficiency of conversion from high-valent metal ions (M(n+1)+) to low-valent ions (Mn+) in the Fenton/Fenton-like catalytic process, enhancing the conversion efficiency safely and effectively would create a great opportunity for the clinical application of CDT. In the study, a universal nanoreactor (NR) consisting of liposome (Lip), tumor cell membrane (CM), and bis(2,4,5-trichloro-6-carboxyphenyl) oxalate (CPPO) is developed to tackle this challenge. The CPPO was first discovered to decompose under weak acidity and H2O2 conditions to generate carboxylic acids (R'COOH) and alcohols (R'OH) with reducibility, which will reduce M(n+1)+ to Mn+ and magnify the effect of CDT. Furthermore, glucose oxidase (GOx) was introduced to decompose glucose in tumor and generate H2O2 and glucose acid, which promote the degradation of CPPO, further strengthening the efficiency of CDT, leading to a butterfly effect. This demonstrated that the butterfly effect triggered by NR and GOx encourages Fenton/Fenton-like reactions of Fe3O4 and MoS2, thereby enhancing the tumor inhibition effect. The strategy of combining GOx and CPPO to strengthen the Fenton/Fenton-like reaction is a universal strategy, which provides a new and interesting perspective for CPPO in the application of CDT, reflecting the exquisite integration of Fenton chemistry and catalytic medicine.


Asunto(s)
Peróxido de Hidrógeno , Peróxido de Hidrógeno/química , Humanos , Hierro/química , Liposomas/química , Glucosa Oxidasa/química , Glucosa Oxidasa/metabolismo , Animales , Propiedades de Superficie , Antineoplásicos/química , Antineoplásicos/farmacología , Oxalatos/química , Ratones , Tamaño de la Partícula , Supervivencia Celular/efectos de los fármacos
5.
Chemosphere ; 358: 142186, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38701860

RESUMEN

Fluorinated compounds (FCs) such as sulfur hexafluoride (SF6) and nitrogen trifluoride (NF3) have garnered attention due to their environmental impact. This study investigates the mineralization and removal of two potent FCs: SF6 and NF3. The results confirm that utilizing various oxalate salts leads to the formation of corresponding metallic fluorides: lithium fluoride (LiF), sodium fluoride (NaF), and potassium fluoride (KF), validating the occurrence of mineralization reactions. Among the oxalate salts, sodium oxalate demonstrates the highest mineralization efficiency in both SF6 and NF3 removal. Real-time Fourier transform infrared spectroscopy (FT-IR) gas-phase analysis confirms rapid and complete gas removal within a short reaction time using the selected oxalate salts. Meticulous mass balance calculations revealed that oxalates (LiF, NaF, and KF) yielded sulfur (S) at rates of 92.09%, 91.85%, and 84.98% following SF6 mineralization. Additionally, the conversion rates of oxalates to the corresponding metallic fluorides (LiF, NaF, and KF) after SF6 mineralization were 98.18%, 95.82%, and 95.21%, respectively. Similarly, after NF3 mineralization, these conversion rates stood at 92.18%, 90.67%, and 90.02%, respectively. The removal efficiencies for SF6 (1000 ppm) were 4.98, 12.01, and 7.23 L/g, while those for NF3 (1000 ppm) were 14.1, 12.6, and 11.7 L/g, respectively. Notably, sodium oxalate exhibits superior effectiveness, achieving 100% SF6 conversion within 30 min and 100% NF3 conversion within 50 min. This work underscores the potential of oxalate mineralization as a promising strategy for efficient and rapid removal of potent fluorinated compounds, paving the way for environmentally benign FC remediation techniques with broader implications for sustainable gas treatment technologies.


Asunto(s)
Fluoruros , Gases de Efecto Invernadero , Oxalatos , Hexafluoruro de Azufre , Oxalatos/química , Hexafluoruro de Azufre/química , Fluoruros/química , Gases de Efecto Invernadero/análisis , Espectroscopía Infrarroja por Transformada de Fourier , Restauración y Remediación Ambiental/métodos
6.
Int J Mol Sci ; 25(8)2024 Apr 20.
Artículo en Inglés | MEDLINE | ID: mdl-38674109

RESUMEN

Although several therapeutic effects have been attributed to wild blackthorn fruits, their use is still negligible. Purification of the antioxidant-active fraction, obtained from wild blackthorn fruits by hot ammonium oxalate extraction (Ao), yielded seven fractions after successive elution with water, sodium chloride and sodium hydroxide solutions. The purified fractions differ in carbohydrates, proteins, and phenolics. About 60% of the applied Ao material was recovered from the column, with the highest yields eluted with 0.25 M NaCl solution, accounting for up to 70 wt% of all eluted material. Analyses have shown that two dominant fractions (3Fa and 3Fb) contain 72.8-81.1 wt% of galacturonic acids, indicating the prevalence of homogalacturonans (HG) with a low acetyl content and a high degree of esterification. The low content of rhamnose, arabinose and galactose residues in both fractions indicates the presence of RG-I associated with arabinogalactan. In terms of yield, the alkali-eluted fraction was also significant, as a dark brown-coloured material with a yield of ~15 wt% with the highest content of phenolic compounds of all fractions. However, it differs from other fractions in its powdery nature, which indicates a high content of salts that could not be removed by dialysis.


Asunto(s)
Antioxidantes , Frutas , Oxalatos , Polisacáridos , Antioxidantes/farmacología , Antioxidantes/química , Frutas/química , Polisacáridos/química , Polisacáridos/farmacología , Oxalatos/química , Extractos Vegetales/química , Extractos Vegetales/farmacología , Pectinas/química , Fenoles/química , Fenoles/análisis , Galactanos/química
7.
J Agric Food Chem ; 72(18): 10163-10178, 2024 May 08.
Artículo en Inglés | MEDLINE | ID: mdl-38653191

RESUMEN

Oxalate decarboxylase (OXDC) is a typical Mn2+/Mn3+ dependent metal enzyme and splits oxalate to formate and CO2 without any organic cofactors. Fungi and bacteria are the main organisms expressing the OXDC gene, but with a significantly different mechanism of gene expression and regulation. Many articles reported its potential applications in the clinical treatment of hyperoxaluria, low-oxalate food processing, degradation of oxalate salt deposits, oxalate acid diagnostics, biocontrol, biodemulsifier, and electrochemical oxidation. However, some questions still remain to be clarified about the role of substrate binding and/or protein environment in modulating the redox properties of enzyme-bound Mn(II)/Mn(III), the nature of dioxygen involved in the catalytic mechanism, and how OXDC acquires Mn(II) /Mn(III). This review mainly summarizes its biochemical and structure characteristics, gene expression and regulation, and catalysis mechanism. We also deep-mined oxalate decarboxylase gene data from National Center for Biotechnology Information to give some insights to explore new OXDC with diverse biochemical properties.


Asunto(s)
Bacterias , Carboxiliasas , Carboxiliasas/genética , Carboxiliasas/metabolismo , Carboxiliasas/química , Bacterias/genética , Bacterias/enzimología , Bacterias/metabolismo , Hongos/genética , Hongos/enzimología , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Proteínas Fúngicas/química , Biocatálisis , Oxalatos/metabolismo , Oxalatos/química , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Proteínas Bacterianas/química , Regulación Enzimológica de la Expresión Génica , Humanos , Catálisis , Animales
8.
Comput Biol Chem ; 110: 108039, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38471352

RESUMEN

Hepatocellular carcinoma (HCC) persists to be one of the most devastating and deadliest malignancies globally. Recent research into the molecular signaling networks entailed in many malignancies has given some prominent insights that can be leveraged to create molecular therapeutics for combating HCC. Therefore, in the current communication, an in-silico drug repurposing approach has been employed to target the function of PTP4A3/PRL-3 protein in HCC using antidepressants: Fluoxetine hydrochloride, Citalopram, Amitriptyline, Imipramine, and Escitalopram oxalate as the desired ligands. The density function theory (DFT) and chemical absorption, distribution, metabolism, excretion, and toxicity (ADMET) parameters for the chosen ligands were evaluated to comprehend the pharmacokinetics, drug-likeness properties, and bioreactivity of the ligands. The precise interaction mechanism was explored using computational methods such as molecular docking and molecular dynamics (MD) simulation studies to assess the inhibitory effect and the stability of the interactions against the protein of interest. Escitalopram oxalate exhibited a comparatively significant docking score (-7.4 kcal/mol) compared to the control JMS-053 (-6.8 kcal/mol) against the PRL-3 protein. The 2D interaction plots exhibited an array of hydrophobic and hydrogen bond interactions. The findings of the ADMET forecast confirmed that it adheres to Lipinski's rule of five with no violations, and DFT analysis revealed a HOMO-LUMO energy gap of -0.26778 ev, demonstrating better reactivity than the control molecule. The docked complexes were subjected to MD studies (100 ns) showing stable interactions. Considering all the findings, it can be concluded that Escitalopram oxalate and related therapeutics can act as potential pharmacological candidates for targeting the activity of PTP4A3/PRL-3 in HCC.


Asunto(s)
Antidepresivos , Carcinoma Hepatocelular , Escitalopram , Neoplasias Hepáticas , Simulación del Acoplamiento Molecular , Proteínas Tirosina Fosfatasas , Humanos , Neoplasias Hepáticas/tratamiento farmacológico , Neoplasias Hepáticas/metabolismo , Carcinoma Hepatocelular/tratamiento farmacológico , Carcinoma Hepatocelular/metabolismo , Proteínas Tirosina Fosfatasas/antagonistas & inhibidores , Proteínas Tirosina Fosfatasas/metabolismo , Antidepresivos/farmacología , Antidepresivos/química , Escitalopram/química , Escitalopram/farmacología , Proteínas de Neoplasias/metabolismo , Proteínas de Neoplasias/antagonistas & inhibidores , Simulación de Dinámica Molecular , Oxalatos/química , Oxalatos/metabolismo , Teoría Funcional de la Densidad , Estructura Molecular , Antineoplásicos/farmacología , Antineoplásicos/química
9.
J Phys Chem Lett ; 15(3): 725-732, 2024 Jan 25.
Artículo en Inglés | MEDLINE | ID: mdl-38215403

RESUMEN

Transporter proteins change their conformations to carry their substrate across the cell membrane. The conformational dynamics is vital to understanding the transport function. We have studied the oxalate transporter (OxlT), an oxalate:formate antiporter from Oxalobacter formigenes, significant in avoiding kidney stone formation. The atomic structure of OxlT has been recently solved in the outward-open and occluded states. However, the inward-open conformation is still missing, hindering a complete understanding of the transporter. Here, we performed a Gaussian accelerated molecular dynamics simulation to sample the extensive conformational space of OxlT and successfully predicted the inward-open conformation where cytoplasmic substrate formate binding was preferred over oxalate binding. We also identified critical interactions for the inward-open conformation. The results were complemented by an AlphaFold2 structure prediction. Although AlphaFold2 solely predicted OxlT in the outward-open conformation, mutation of the identified critical residues made it partly predict the inward-open conformation, identifying possible state-shifting mutations.


Asunto(s)
Simulación de Dinámica Molecular , Oxalatos , Oxalatos/química , Oxalatos/metabolismo , Proteínas de Transporte de Membrana/química , Antiportadores/metabolismo , Formiatos/metabolismo , Conformación Proteica
10.
Int J Phytoremediation ; 26(7): 1154-1167, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38149624

RESUMEN

The discharge of colored effluent into water bodies is a big concern; hence, the current work was designed to fabricate a superior nanocomposite (NBM) using the Newbouldia laevis husk (NB) and functionalized multiwalled carbon nanotubes (f-MWCNTs) for the adsorption of malachite green oxalate (MGO). Brunauer-Emmett-Teller (BET) surface analysis was used to assess the specific surface area of NB (0.7699 m2 g-1) and NBM (94.006 m2 g-1). Fourier transform infrared spectroscopy (FTIR) was employed to determine the chemical moieties on the surface of the adsorbent. Field emission scanning electron microscopy (FESEM) and thermogravimetric analysis (TGA) were used to analyze the surface morphology and the thermal behavior of the adsorbents. Essential factors of the adsorption process were investigated, and it was revealed that pH 6.0, adsorbent dose of 0.05 g, contact time 80 min, concentration of 100 mg dm-3 and maximum adsorption capacity of 35.78 mg g-1 (NB) and 69.97 mg g-1 (NBM) were the optimal parameters. The NB and NBM adsorption processes followed a pseudo-first-order kinetic model. The exothermic and endothermic adsorptive processes were noticed to be the best descriptions of MGO elimination by NB and NBM, respectively. The uptake of MGO by NB and NBM was best described by models of Freundlich and Langmuir isotherms. Besides, NBM demonstrated uptake efficiency that is >80% after the fourth adsorption/desorption cycle. As a result, NBM has a wide range of possible uses in environmental remediation.


The husk of Newbouldia laevis is a frequent waste that must be managed properly. This paper describes the application of Newbouldia laevis husk as a value-added material for the design of a water treatment agent. The use of carbon nanotube in the modification of Newbouldia laevis husk would have a synergistic effect on the overall property of the nanocomposite. Nanocomposite synthesized from multiwalled carbon nanotubes (MWCNTs) and Newbouldia laevis husk were characterized and used for the sequestration of malachite green oxalate from contaminated water. Our primary goal is to optimize the nanocomposite by varying factors of adsorption such as solution pH, equilibrium, kinetic, thermodynamic, and regeneration studies. We believe that this study will contribute to the existing knowledge of Newbouldia laevis husk. Owing to the exceptional potential of the nanocomposite, this adsorbent can be extended to possible field applications.


Asunto(s)
Nanocompuestos , Nanotubos de Carbono , Colorantes de Rosanilina , Termodinámica , Contaminantes Químicos del Agua , Colorantes de Rosanilina/química , Cinética , Adsorción , Nanotubos de Carbono/química , Biodegradación Ambiental , Oxalatos/química
11.
Environ Pollut ; 343: 123205, 2024 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-38142033

RESUMEN

The oxidation of hexachlorocyclohexane isomers in the aqueous phase (Milli-Q and groundwater) was studied using persulfate activated by ferrioxalate and solar light at circumneutral pH. The experiments were conducted in a solar simulator reactor with local radiation fluxes qw= 1.12·10-7 E cm-2s-1 and in compound parabolic collectors with solar light (qw≈10-7 E cm-2s-1) for 390 min. The effect of activator dosage (18-125 µM ferrioxalate) and persulfate concentration (520-2600 µM) on hexachlorocyclohexane conversion and oxalate and oxidant consumption was analyzed. Conversion of about 95% of ß isomer was achieved at 390 min using 1300 µM of initial persulfate and 63 µM of Fe3+ concentration despite this ß isomer being the most recalcitrant to oxidation (XHexachlorocyclohexanes=0.98). Dechlorination above 80% was achieved under these conditions, analyzing the chlorides released into the water. The influence of chloride and bicarbonate on hexachlorocyclohexanes degradation was analyzed in milli-Q water and in groundwater. Hexachlorocyclohexane conversion at 390 min decreases from 98% to 83, 75 and 65% in the presence of chloride, bicarbonate or groundwater, respectively. Results obtained with compound parabolic collectors and solar light using 2600 µM Na2S2O8 and 63 µM Fe for removing hexachlorocyclohexanes agreed with those from the solar simulator reactor, supporting using solar light to activate persulfate for sustainable abatement of persistent organic pollutants in aqueous matrixes.


Asunto(s)
Agua Subterránea , Plaguicidas , Contaminantes Químicos del Agua , Hexaclorociclohexano , Bicarbonatos , Cloruros , Oxalatos/química , Agua Subterránea/química , Agua , Oxidación-Reducción , Contaminantes Químicos del Agua/análisis , Sulfatos/química
12.
Chemosphere ; 339: 139790, 2023 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-37572712

RESUMEN

A photochemical system combining iron (hydr)oxides and oxalate (Ox) shows application prospects in wastewater treatment due to the abundance of reactive oxygen species (ROS) generation. Nevertheless, it is a challenge to the investigate photochemical activity of iron (hydr)oxides/Ox systems with varying structural properties. Herein, the photochemical behaviors of Ox on goethite (Gt) surface from the view of structural dependent activity, containment degradation, and ROS generation were explored in detail. Results confirmed that bidentate mononuclear was formed on Gt surface after complexing Ox. Combined with density functional theory calculation and pH time evolution during aniline degradation, the photochemical activity of the Gt/Ox system fell in between that of ferrihydrite/Ox and hematite/Ox systems. After irradiating 120 min visible light, 96.5% aniline was degraded by 1.0 mM Ox and 0.2 g/L Gt. The amount of •OH in vis/Gt/Ox system could be up to 309.3 µM and its generation was closely associated with Fe(II) while slightly affected by the generated H2O2. Moreover, as revealed by high-performance liquid chromatography with mass spectrometric and Ecological Structure Activity Relationships software, the toxicity of the intermediates of aniline degradation in the vis/Gt/Ox system towards fish and green algae increased first but then declined accompanied by the generation of non-toxic ring-opening products at the end of reaction. According to the findings in the presented study, it could be concluded that vis/Gt/Ox is a promising approach to wiping out aniline wastewater.


Asunto(s)
Radical Hidroxilo , Oxalatos , Oxalatos/química , Radical Hidroxilo/química , Peróxido de Hidrógeno/química , Especies Reactivas de Oxígeno , Oxidación-Reducción , Compuestos Férricos/toxicidad , Compuestos Férricos/química , Hierro/química , Óxidos
13.
Fungal Biol ; 127(7-8): 1187-1197, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37495308

RESUMEN

Cerium is the most sought-after rare earth element (REE) for application in high-tech electronic devices and versatile nanomaterials. In this research, biomass-free spent culture media of Aspergillus niger and Neurospora crassa containing precipitant ligands (oxalate, carbonate) were investigated for their potential application in biorecovery of Ce from solution. Precipitation occurred after Ce3+ was mixed with biomass-free spent culture media and >99% Ce was recovered from media of both organisms. SEM showed that biogenic crystals with distinctive morphologies were formed in the biomass-free spent medium of A. niger. Irregularly-shaped nanoparticles with varying sizes ranging from 0.5 to 2 µm and amorphous biominerals were formed after mixing the carbonate-laden N. crassa supernatant, resulting from ureolysis of supplied urea, with Ce3+. Both biominerals contained Ce as the sole metal, and X-ray diffraction (XRD) and thermogravimetric analyses identified the biominerals resulting from the biomass-free A. niger and N. crassa spent media as cerium oxalate decahydrate [Ce2(C2O4)3·10H2O] and cerium carbonate [Ce2(CO3)3·8H2O], respectively. Thermal decomposition experiments showed that the biogenic Ce oxalates and carbonates could be subsequently transformed into ceria (CeO2). FTIR confirmed that both amorphous and nanoscale Ce carbonates contained carbonate (CO32-) groups. FTIR-multivariate analysis could classify the biominerals into three groups according to different Ce concentrations and showed that Ce carbonate biominerals of higher purity were produced when precipitated at higher Ce3+ concentrations. This work provides new understanding of fungal biotransformations of soluble REE species and their biorecovery using biomass-free fungal culture systems and indicates the potential of using recovered REE as precursors for the biosynthesis of novel nanomaterials.


Asunto(s)
Cerio , Oxalatos/química , Carbonatos/química , Biotransformación , Medios de Cultivo/química
14.
Nat Commun ; 14(1): 1730, 2023 04 03.
Artículo en Inglés | MEDLINE | ID: mdl-37012268

RESUMEN

An oxalate-degrading bacterium in the gut microbiota absorbs food-derived oxalate to use this as a carbon and energy source, thereby reducing the risk of kidney stone formation in host animals. The bacterial oxalate transporter OxlT selectively uptakes oxalate from the gut to bacterial cells with a strict discrimination from other nutrient carboxylates. Here, we present crystal structures of oxalate-bound and ligand-free OxlT in two distinct conformations, occluded and outward-facing states. The ligand-binding pocket contains basic residues that form salt bridges with oxalate while preventing the conformational switch to the occluded state without an acidic substrate. The occluded pocket can accommodate oxalate but not larger dicarboxylates, such as metabolic intermediates. The permeation pathways from the pocket are completely blocked by extensive interdomain interactions, which can be opened solely by a flip of a single side chain neighbouring the substrate. This study shows the structural basis underlying metabolic interactions enabling favourable symbiosis.


Asunto(s)
Microbioma Gastrointestinal , Oxalatos , Animales , Oxalatos/química , Proteínas Bacterianas/metabolismo , Proteínas de Transporte de Membrana/metabolismo , Transporte Biológico , Bacterias/metabolismo
15.
Mar Pollut Bull ; 189: 114823, 2023 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-36931154

RESUMEN

Mutual transformations of rhizospheric arsenic (As) in pollution-prone mangrove sediments affected by root exudate oxalate were simulated. This study focuses on the effect of oxalate on As release, mobilization, and phase speciation associated with P and Fe was examined under anoxic conditions in time-dependent changes. Results showed that oxalate addition significantly facilitated As-Fe-P release from As-contaminated mangrove sediments. Sediment As formed the adsorptive and the carbonate-binding fractionations, facilitating the re-adsorption processes. Solution As and As5+ correlated with NaOH-P positively but with NaHCO3-P and HCl-P negatively. Dominant Fe3+ (>84 %) from the amorphous Fe regulated suspension changes and then time-dependent co-precipitation with As and P. Sediment P formed strong complexes with Fe oxides and could be substituted for As via STEM analysis. Oxalate ligand exchange, competitive adsorption of oxalate, and Fe-reduced dissolution are confirmed to involve, allowing for an insight As/P/Fe mobilization and fate in mangrove wetland.


Asunto(s)
Arsénico , Hierro , Hierro/química , Arsénico/análisis , Oxalatos/química , Fosfatos , Contaminación Ambiental , Sedimentos Geológicos/química
16.
Int J Mol Sci ; 23(23)2022 Nov 25.
Artículo en Inglés | MEDLINE | ID: mdl-36499066

RESUMEN

To clarify the crystal chemical features of natural and synthetic oxalates Me2+(C2O4)∙2H2O (Me2+ = Fe, Mn, Mg, Zn), including minerals of the humboldtine group, solid solutions of lindbergite Mn(C2O4)∙2H2O−glushinskite Mg(C2O4)∙2H2O were precipitated under various conditions, close to those characteristic of mineralization in biofilms: at the stoichiometric ratios ((Mn + Mg)/C2O4 = 1) and non-stochiometric ratios ((Mn + Mg)/C2O4 < 1), in the presence and absence of citrate ions. Investigation of precipitates was carried out by powder X-ray diffraction, scanning electron microscopy and energy-dispersive X-ray spectroscopy. Thermodynamic modelling was performed in order to evaluate the lindbergite−glushinskite equilibrium. It was shown that glushinskite belongs to the orthorhombic ß-modification (sp. Gr. Fddd), while lindbergite has a monoclinic α-modification (sp. gr. C2/c). Mg ions incorporate lindbergite in much higher quantities than Mn ions incorporate glushinskite; moreover, Mn glushinskites are characterized by violations of long-range order in their crystal structure. Lindbergite−glushinskite transition occurs abruptly and can be classified as a first-order isodimorphic transition. The Me2+/C2O4 ratio and the presence of citric acid in the solution affect the isomorphic capacity of lindbergite and glushinskite, the width of the transition and the equilibrium Mg/Mn ratio. The transition is accompanied by continuous morphological changes in crystals and crystal intergrowths. Given the obtained results, it is necessary to take into account in biotechnologies aimed at the bioremediation/bioleaching of metals from media containing mixtures of cations (Mg, Mn, Fe, Zn).


Asunto(s)
Oxalatos , Difracción de Rayos X , Oxalatos/química , Microscopía Electrónica de Rastreo , Iones
17.
J Am Chem Soc ; 144(42): 19603-19610, 2022 10 26.
Artículo en Inglés | MEDLINE | ID: mdl-36239996

RESUMEN

An oxalate-assisted lanthanide (Ln) incorporation strategy is first demonstrated for creating rare high-nuclearity Ln-containing polyoxoniobates (PONbs). With the strategy, a series of high-nuclearity Ln-containing PONbs of 50-nuclearity Dy2Nb48, 103-nuclearity Dy7Nb96, 200-nuclearity Dy10Nb190, and 206-nuclearity Dy14Nb192 have been made, showing an increasingly large structure evolution from Dy2Nb48 monomer to Dy7Nb96 dimer and to distinct Dy10Nb190 and Dy14Nb192 tetramers. Among them, Dy14Nb192 presents the largest heterometallic PONb and also the PONb with the greatest number of Ln ions reported thus far. Interestingly, both giant Dy14Nb192 and Dy10Nb190 molecules can further undergo single-crystal to single-crystal intermolecular aggregations, forming infinite {Dy14Nb192}∞ and {Dy10Nb190}∞ chains, respectively. The former structural transformation shows a reversible humidity-dependent aggregation-disaggregation process accompanied by a proton conductivity response, while the latter structural transformation is irreversible. These new species largely enrich the very limited members of Ln-containing PONb family and offer rare examples for studying structural transformations between giant molecular aggregates and infinitely extended structures at the atomic level.


Asunto(s)
Elementos de la Serie de los Lantanoides , Elementos de la Serie de los Lantanoides/química , Protones , Modelos Moleculares , Iones , Oxalatos/química
18.
Chem Commun (Camb) ; 58(83): 11657-11660, 2022 Oct 18.
Artículo en Inglés | MEDLINE | ID: mdl-36164825

RESUMEN

A Ru/NH2-MCM-41 catalyst was prepared via a coordination-assisted strategy for chemoselective hydrogenation of dimethyl oxalate with a high selectivity of methyl glycolate (ca. 100%) and ethylene glycol (>90%) at reaction temperatures of 343 K and 433 K, respectively. The amino groups help to anchor and form stable electron-rich Ru active sites, which accounts for the excellent CO bond activation and hydrogenation selectivity.


Asunto(s)
Glicol de Etileno , Oxalatos , Catálisis , Glicol de Etileno/química , Glicolatos , Hidrogenación , Oxalatos/química
19.
Acta Crystallogr C Struct Chem ; 78(Pt 4): 212-217, 2022 04 01.
Artículo en Inglés | MEDLINE | ID: mdl-35380123

RESUMEN

The X-ray structure of racemic tris(ethane-1,2-diamine-κ2N,N')cobalt(III) tris(oxalato-κ2O1,O2)cobaltate(III) pentahydrate, [Co(C2H8N2)3][Co(C2O4)3]·5H2O or [Co(en)3][Co(ox)3]·5H2O, has been determined. Hydrogen-bonding interactions along the C3-axis of the [Co(en)3]3+ cation with the [Co(ox)3]3- anion are heterochiral, while those perpendicular to this axis are homochiral. Implications for the interpretation of chiral discriminations and induction in electron-transfer reactions in solution are discussed.


Asunto(s)
Etano , Oxalatos , Cristalografía por Rayos X , Diaminas , Etilenodiaminas , Enlace de Hidrógeno , Oxalatos/química , Rayos X
20.
Int J Mol Sci ; 23(3)2022 Jan 29.
Artículo en Inglés | MEDLINE | ID: mdl-35163480

RESUMEN

We report a new structure of {[Co(bpy)2(ox)][{Cu2(bpy)2(ox)}Fe(ox)3]}n·8.5nH2O NCU-1 presenting a rare ladder topology among oxalate-based coordination polymers with anionic chains composed of alternately arranged [Cu2(bpy)2(ox)]2+ and [Fe(ox)3]3- moieties. Along the a axis, they are separated by Co(III) units to give porous material with voids of 963.7 Å3 (16.9% of cell volume). The stability of this structure is assured by a network of stacking interactions and charge-assisted C-H…O hydrogen bonds formed between adjacent chains, adjacent cobalt(III) units, and alternately arranged cobalt(III) and chain motifs. The soaking experiment with acetonitrile and bromobenzene showed that water molecules (8.5 water molecules dispersed over 15 positions) are bonded tightly, despite partial occupancy. Water adsorption experiments are described by a D'arcy and Watt model being the sum of Langmuir and Dubinin-Serpinski isotherms. The amount of primary adsorption sites calculated from this model is equal 8.2 mol H2O/mol, being very close to the value obtained from the XRD experiments and indicates that water was adsorbed mainly on the primary sites. The antiferromagnetic properties could be only approximately described with the simple CuII-ox-CuII dimer using H = -J·S1·S2, thus, considering non-trivial topology of the whole Cu-Fe chain, we developed our own general approach, based on the semiclassical model (SC) and molecular field (MF) model, to describe precisely the magnetic superexchange interactions in NCU-1. We established that Cu(II)-Cu(II) coupling dominates over multiple Cu(II)-Fe(III) interactions, with JCuCu = -275(29) and JCuFe = -3.8(1.6) cm-1 and discussed the obtained values against the literature data.


Asunto(s)
Fenómenos Magnéticos , Metales/química , Oxalatos/química , Adsorción , Cristalización , Dimerización , Enlace de Hidrógeno , Modelos Moleculares , Conformación Molecular , Espectrofotometría Infrarroja , Espectroscopía Infrarroja por Transformada de Fourier , Temperatura , Agua/química , Espectroscopía de Absorción de Rayos X
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