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2.
Brain Behav Immun ; 2024 Aug 24.
Artículo en Inglés | MEDLINE | ID: mdl-39187048

RESUMEN

The prevalence of bacterial infections significantly increases among patients with severe traumatic brain injury (STBI), leading to a notable rise in mortality rates. While immune dysfunctions are linked to the incidence of pneumonia, our observations indicate that endogenous pathogens manifest in the lungs post-STBI due to the migration of gut commensal bacteria. This translocation involves gut-innervating nociceptor sensory neurons, which are crucial for host defense. Following STBI, the expression of transient receptor potential vanilloid 1 (TRPV1) in dorsal root ganglion (DRG) neurons significantly decreases, despite an initial brief increase. The timing of TRPV1 defects coincides with the occurrence of pulmonary infections post-STBI. This alteration in TRPV1+ neurons diminishes their ability to signal bacterial injuries, weakens defense mechanisms against intestinal bacteria, and increases susceptibility to pulmonary infections via bacterial translocation. Experimental evidence demonstrates that pulmonary infections can be successfully replicated through the chemical ablation and gene interference of TRPV1+ nociceptors, and that these infections can be mitigated by TRPV1 activation, thereby confirming the crucial role of nociceptor neurons in controlling intestinal bacterial migration. Furthermore, TRPV1+ nociceptors regulate the immune response of microfold cells by releasing calcitonin gene-related peptide (CGRP), thereby influencing the translocation of gut bacteria to the lungs. Our study elucidates how changes in nociceptive neurons post-STBI impact intestinal pathogen defense. This new understanding of endogenous risk factors within STBI pathology offers novel insights for preventing and treating pulmonary infections.

4.
Food Res Int ; 191: 114648, 2024 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-39059902

RESUMEN

In the present study, different oligosaccharides (fructooligosaccharide (FOS), galactooligosaccharide (GOS), isomaltooligosaccharide (IMO), and xylooligosaccharide (XOS)) were modified on casein (CN) via Maillard reaction. The CN-oligosaccharide conjugates were evaluated for modifications to functional groups, fluorescence intensity, water- and oil-holding properties, emulsion foaming properties, as well as general emulsion properties and stability. The results demonstrated that the covalent combination of CN and oligosaccharides augmented the spatial repulsion and altered the hydrophobic milieu of proteins, which resulted in a diminution in water-holding capacity, an augmentation in oil-holding capacity, and an enhancement in the emulsification properties of proteins. Among them, CN-XOS exhibited the most pronounced changes, with the emulsification activity index and emulsion stability index increasing by approximately 72% and 84.3%, respectively. Furthermore, CN-XOS emulsions have smaller droplet sizes and higher absolute potential values than CN emulsions. Additionally, CN-XOS emulsions demonstrate remarkable stability when ion concentration and pH are varied. These findings indicate that oligosaccharides modified via Maillard reaction can be used as good natural emulsifiers. This provides a theoretical basis for using oligosaccharides to modify proteins and act as natural emulsifiers.


Asunto(s)
Caseínas , Emulsionantes , Emulsiones , Reacción de Maillard , Oligosacáridos , Oligosacáridos/química , Caseínas/química , Emulsionantes/química , Emulsiones/química , Concentración de Iones de Hidrógeno , Tamaño de la Partícula , Interacciones Hidrofóbicas e Hidrofílicas , Agua/química
6.
Angew Chem Int Ed Engl ; : e202411197, 2024 Jun 27.
Artículo en Inglés | MEDLINE | ID: mdl-38935406

RESUMEN

The zeolite-catalyzed methanol-to-aromatics (MTA) process is a promising avenue for industrial decarbonization. This process predominantly utilizes 3-dimensional 10-member ring (10-MR) zeolites like ZSM-5 and ZSM-11, chosen for their confinement effect essential for aromatization. Current research mainly focuses on enhancing selectivity and mitigating catalyst deactivation by modulating zeolites' physicochemical properties. Despite the potential, the MTA technology is at a low Technology Readiness Level, hindered by mechanistic complexities in achieving the desired selectivity towards liquid aromatics. To bridge this knowledge gap, this study proposes a roadmap for MTA catalysis by strategically combining controlled catalytic experiments with advanced characterization methods (including operando conditions and "mobility-dependent" solid-state NMR spectroscopy). It identifies the descriptor-role of Koch-carbonylated intermediates, longer-chain hydrocarbons, and the zeolites' intersectional cavities in yielding preferential liquid aromatics selectivity. Understanding these selectivity descriptors and architectural impacts is vital, potentially advancing other zeolite-catalyzed emerging technologies.

7.
Dalton Trans ; 53(27): 11344-11353, 2024 Jul 09.
Artículo en Inglés | MEDLINE | ID: mdl-38899920

RESUMEN

In the context of advancing social modernization, the projected shortfall in the demand for renewable aromatic hydrocarbons is expected to widen, influenced by industries like high-end materials, pharmaceuticals, and consumer goods. Sustainable methods for aromatic production from alternative sources, particularly the methanol-to-aromatics (MTA) process using zeolite ZSM-5 and associated with the "methanol economy", have garnered widespread attention. To facilitate this transition, our project consolidates conventional strategies that impact aromatics selectivity-such as using hierarchical zeolites, metallic promoters, or altering zeolite physicochemical properties-into a unified study. Our findings demonstrate the beneficial impact of elongated crystal size and heightened zeolite hierarchy on preferential aromatics selectivity, albeit through distinct mechanisms involving the consumption of shorter olefins. While metallic promoters enhance MTA performance, crystal size, and hierarchy remain pivotal in achieving the maximized aromatics selectivity. This study contributes to a deeper understanding of achieving superior aromatics selectivity through physicochemical modifications in zeolite ZSM-5 during MTA catalysis, thereby advancing the field's comprehension of structure-reactivity relationships.

8.
Int Immunopharmacol ; 137: 112492, 2024 Aug 20.
Artículo en Inglés | MEDLINE | ID: mdl-38906005

RESUMEN

BACKGROUND: Local treatment may function synergistically with immunotherapy and targeted agents. This study aimed to assess the effectiveness and safety of transcatheter arterial chemoembolization (TACE) and hepatic artery infusion chemotherapy (HAIC) combined with tyrosine kinase inhibitors (TKIs) and programmed death-1 (PD-1) inhibitors in patients with initially unresectable hepatocellular carcinoma (uHCC). METHODS: A retrospective study was conducted on patients diagnosed with initially uHCC who received combined treatment of TACE-HAIC combined with TKIs and PD-1 inhibitors from July 2020 to February 2023. The primary endpoints were overall survival (OS) and progression free survival (PFS) and adverse events (AEs). Objective response rate (ORR), disease control rate (DCR) and conversion surgery rate (CSR), whereas the secondary endpoints. RESULTS: After screening, a total of 62 patients were selected for this study. The overall median OS was 18.2 (95% CI 16.24-20.16) months and median PFS was 9.2 (95% CI 7.24-11.16) months. Based on the modified Response Evaluation Criteria in Solid Tumors (mRECIST) criteria and RECIST v1.1 criteria, ORR was 67.7% (42/62), and the DCR was 90.3% (56/62), the CSR was 27.4% (17/62). The most common treatment-emergent adverse events (TEAEs) were transaminitis (56.4%, 35/62), nausea and vomiting (43.5%, 27/62), thrombocytopenia (37.1%, 23/62), abdominal pain (33.9%, 21/62), and fever (33.9%, 21/62). CONCLUSIONS: TKIs combined with PD-1 inhibitors plus TACE-HAIC therapy represents an effective and tolerable treatment option in patients with uHCC. Patients undergoing surgery after combination therapy may have survival benefits.


Asunto(s)
Carcinoma Hepatocelular , Quimioembolización Terapéutica , Inhibidores de Puntos de Control Inmunológico , Neoplasias Hepáticas , Inhibidores de Proteínas Quinasas , Humanos , Carcinoma Hepatocelular/terapia , Carcinoma Hepatocelular/tratamiento farmacológico , Carcinoma Hepatocelular/mortalidad , Neoplasias Hepáticas/terapia , Neoplasias Hepáticas/tratamiento farmacológico , Neoplasias Hepáticas/mortalidad , Masculino , Femenino , Persona de Mediana Edad , Quimioembolización Terapéutica/métodos , Quimioembolización Terapéutica/efectos adversos , Estudios Retrospectivos , Anciano , Inhibidores de Proteínas Quinasas/uso terapéutico , Inhibidores de Proteínas Quinasas/efectos adversos , Inhibidores de Proteínas Quinasas/administración & dosificación , Inhibidores de Puntos de Control Inmunológico/uso terapéutico , Inhibidores de Puntos de Control Inmunológico/efectos adversos , Adulto , Receptor de Muerte Celular Programada 1/antagonistas & inhibidores , Resultado del Tratamiento , Terapia Combinada , Infusiones Intraarteriales , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Protocolos de Quimioterapia Combinada Antineoplásica/efectos adversos , Arteria Hepática
9.
Langenbecks Arch Surg ; 409(1): 168, 2024 May 30.
Artículo en Inglés | MEDLINE | ID: mdl-38819706

RESUMEN

PURPOSE: To evaluate the safety and efficacy of two-step vascular exclusion and in situ hypothermic portal perfusion in patients with end-stage hepatic hydatidosis. METHODS: This study involved patients with advanced hepatic hydatid disease undergoing surgical treatment between 2022 and 2023, which included resection and reconstruction of the hepatic veins, inferior vena cava (IVC), and portal vein (PV). We described the technical details of liver resection and vascular reconstruction, as well as the use of two-step vascular exclusion and in situ hypothermic portal perfusion techniques during the vascular reconstruction process. RESULT: We included 7 patients with advanced hepatic hydatid disease who underwent surgical resection using two-step vascular exclusion and in situ hypothermic portal perfusion. The mean duration of surgery was 12.5 h (range, 7.5-15.0 h). The average hepatic ischemia time was 45 min (range, 25-77 min), while the occlusion time of the IVC was 87 min (range, 72-105 min). The total blood loss was 1000 milliliters (range, 500-1250 milliliters). Postoperatively, patients exhibited good recovery of liver and renal function. The mean ICU stay was 2 days (range, 1-3 days), and the mean postoperative hospital stay was 13 days (range, 9-16 days), with no Grade III or above complications observed during a mean follow-up period of 15 months (range, 9-24 months), CONCLUSION: two-step vascular exclusion and in situ hypothermic portal perfusion for surgical resection of end-stage hepatic hydatid disease is safe and effective. This significantly reduces the anhepatic time.


Asunto(s)
Equinococosis Hepática , Hepatectomía , Vena Porta , Vena Cava Inferior , Humanos , Equinococosis Hepática/cirugía , Equinococosis Hepática/diagnóstico por imagen , Masculino , Femenino , Hepatectomía/métodos , Adulto , Persona de Mediana Edad , Vena Porta/cirugía , Vena Cava Inferior/cirugía , Hipotermia Inducida , Resultado del Tratamiento , Perfusión/métodos , Estudios Retrospectivos , Venas Hepáticas/cirugía , Anciano
10.
J Dairy Sci ; 107(7): 4161-4173, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38246556

RESUMEN

Whey protein isolate (WPI)-based nanodelivery systems have recently attracted an increasing amount of attention. Despite this, research focusing on milk protein concentrate (MPC) and micellar casein (MCC) as carriers loaded in hydrophobic compounds is lacking. This study investigated the mediated effect of docosahexaenoic acid (DHA) in 3 different milk proteins for the embedding of astaxanthin (ASTA) after ultrasound-assisted pH-shifting treatment. We then evaluated the application of milk protein carriers in cheese processing by comparing MPC, MCC, and WPI. The particle size, polydispersity index, and zeta potential results of the milk protein-DHA complex suggested that the addition of 0.36 µmol/mL DHA optimized the delivery of milk protein to ASTA. All 3 DHA-mediated milk proteins induced an improvement in encapsulation efficiency and antioxidant properties of ASTA. Furthermore, the DHA-mediated MPC and MCC played a stronger role in improving the bioaccessibility and thermal and storage stability of ASTA than those without DHA. Tests conducted to examine the application in cheese production indicated that MCC carrier had a positive effect on the texture of cheeses. However, the delivery effect was dependent on the milk protein variety, and MCC exhibited the best protection ability of ASTA, followed by MPC and WPI. The simulated digestion and storage stability results of cheese further confirmed that the protein encapsulation mediated by DHA was more conducive to ASTA absorption. These findings suggested that the DHA-mediated milk protein complexes studied here may be suitable hydrophilic delivery carriers for the hydrophobic nutrient ASTA, potentially playing different roles in improving its storage stability and bioaccessibility.


Asunto(s)
Queso , Ácidos Docosahexaenoicos , Proteínas de la Leche , Xantófilas , Animales , Concentración de Iones de Hidrógeno , Proteína de Suero de Leche , Caseínas
11.
J Ethnopharmacol ; 325: 117825, 2024 May 10.
Artículo en Inglés | MEDLINE | ID: mdl-38296175

RESUMEN

ETHNOPHARMACOLOGICAL RELEVANCE: As a classic traditional Chinese medicine, Magnolia officinalis (M. officinalis) is widely used in digestive diseases. It has rich gastrointestinal activity including inflammatory bowel disease (IBD) treatment, but the mechanism is not clear. AIM OF THE STUDY: In recent years, there has been a growing interest in investigating the regulatory effects of herbal compounds on transient receptor potential (TRP) channel proteins. Transient receptor potential vanilloid 4 (TRPV4), a subtype involved in endothelial permeability regulation, was discussed as the target of M. officinalis in the treatment of IBD in the study. Based on the targeting effect of TRPV4, this study investigated the active ingredients and mechanism of M. officinalis extract in treating IBD. MATERIALS AND METHODS: To reveal the connection between the active ingredients in M. officinalis and TRPV4, a bioactivity-guided high performance liquid chromatography system coupled with mass spectrometry identification was utilized to screen for TRPV4 antagonists. TRPV4 siRNA knockdown experiment was employed to validate the significance of TRPV4 as a crucial target in regulating endothelial permeability by honokiol (HON). The interaction of the active ingredient representing HON with TRPV4 was confirmed by molecular docking, fluorescence-based thermal shift and live cell calcium imaging experiments. The potential binding sites and inhibitory mechanisms of HON in TRPV4 were analyzed by molecular dynamics simulation and microscale thermophoresis. The therapeutic effect of HON based on TRPV4 was discussed in DSS-IBD mice. RESULTS: Our finding elucidated that the inhibitory activity of M. officinalis against TRPV4 is primarily attributed to HON analogues. The knockdown of TRPV4 expression significantly impaired the calcium regulation and permeability protection in endothelial cells. The mechanism study revealed that HON specifically targets the Q239 residue located in the ankyrin repeat domain of TRPV4, and competitively inhibits channel opening with adenosine triphosphate (ATP) binding. The immunofluorescence assay demonstrated that the administration of HON enhances the expression and location of VE-Cadherin to protect the endothelial barrier and attenuates immune cell infiltration. CONCLUSIONS: The finding suggested that HON alleviates IBD by improving endothelial permeability through TRPV4. The discovery provides valuable insights into the potential therapeutic strategy of active natural products for alleviating IBD.


Asunto(s)
Compuestos Alílicos , Repetición de Anquirina , Compuestos de Bifenilo , Enfermedades Inflamatorias del Intestino , Fenoles , Ratones , Animales , Células Endoteliales , Canales Catiónicos TRPV/metabolismo , Calcio/metabolismo , Simulación del Acoplamiento Molecular , Enfermedades Inflamatorias del Intestino/tratamiento farmacológico , Enfermedades Inflamatorias del Intestino/metabolismo , Permeabilidad
12.
Int J Biol Macromol ; 259(Pt 1): 129148, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38176483

RESUMEN

This study explored the improvement of casein (CN)'s properties by conjugating it with oligosaccharides, namely, fructooligosaccharide (FOS), galactooligosaccharide (GOS), isomaltooligosaccharide (IMO), and xylo-oligosaccharide (XOS) via Maillard reaction to identify the most optimal oligosaccharides and modification conditions. The degree of grafting was 30.5 ± 0.41 % for CN-FOS, 33.7 ± 0.62 % for CN-GOS, 38.9 ± 0.51 % for CN-IMO, and 43.7 ± 0.54 % for CN-XOS. With the degree of grafting rising, more oligosaccharides were conjugated, causing greater changes in CN properties. The CN-XOS underwent significant alterations, as the introduction of oligosaccharides led to a decrease in particle size by around 51 nm. Furthermore, the hydroxyl groups caused a reduction in surface hydrophobicity, which in turn decreased the proportion of hydrophobic groups. The solubility of CN-XOS increased significantly at pH 3, by approximately 30.99 %. Additionally, the conjugation of oligosaccharides substantially boosted the rates of DPPH, ABTS, and -OH radical scavenging by 4.61 times, 2.20 times, and 2.58 times, respectively, and also improved the thermal stability of the modified CN. Moreover, the process lowered the protein digestibility, possibly enhancing its applicability as an active substance transporter. This research offers additional theoretical backing for altering CN with oligosaccharides and implementing it in the food and pharmaceutical sectors.


Asunto(s)
Caseínas , Reacción de Maillard , Solubilidad , Oligosacáridos/química , Antígenos
13.
Int J Biol Macromol ; 255: 128274, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-37989432

RESUMEN

Heavy metal ions (HMIs) have been widely applied in various industries because of their excellent physicochemical properties. However, their discharging without appropriate treatment brought about serious pollution problems. So it is desirable but challenging to rapidly and completely clean up these toxic pollutants from water, especially utilizing environmentally friendly and naturally rich biomass materials. In this work, we prepared nanocellulose/carbon dots/magnesium hydroxide (CCMg) ternary composite using cotton via a simple hydrothermal method. The removal mechanism towards Cd2+ and Cu2+ was investigated using a combination of experimental techniques and density functional theory calculations. CCMg shows a good ability to remove HMIs. It is realized that the interaction between each component of CCMg and cadmium nitrate is mainly of hydrogen/dative bonds. Cadmium nitrate is preferentially enriched by the Mg(OH)2 moiety, proved by calculated thermodynamics, interfacial interactions and charges. After transformation, the cadmium carbonate precipitate is fixed on the surface by nanocellulose (NC) via chemical coupling; and of interest is that copper ion precipitates in the form of basic sulfate. Due to its high adsorption effect and simple recovery operation, CCMg is having a wide range of application prospects as a water treatment agent.


Asunto(s)
Metales Pesados , Contaminantes Químicos del Agua , Aguas Residuales , Carbono , Metales Pesados/química , Cadmio/química , Nitratos , Adsorción , Iones , Contaminantes Químicos del Agua/química , Cinética , Concentración de Iones de Hidrógeno
14.
Chin Herb Med ; 15(4): 496-508, 2023 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-38094018

RESUMEN

Ischemic stroke (IS) is a severe cerebrovascular disease with a high incidence, mortality, and disability rate. The first-line treatment for IS is the use of recombinant tissue plasminogen activator (r-tPA). Regrettably, numerous patients encounter delays in treatment due to the narrow therapeutic window and the associated risk of hemorrhage. Traditional Chinese medicine (TCM) has exhibited distinct advantages in preventing and treating IS. TCM enhances cerebral microcirculation, alleviates neurological disorders, regulates energy metabolism, mitigates inflammation, reduces oxidative stress injuries, and inhibits apoptosis, thereby mitigating brain damage and preventing IS recurrence. This article summarizes the etiology, pathogenesis, therapeutic strategies, and relationship with modern biology of IS from the perspective of TCM, describes the advantages of TCM in the treatment of IS, and further reviews the pharmacodynamic characteristics and advantages of TCM in the acute and recovery phases of IS as well as in post-stroke complications. Additionally, it offers valuable insights and references for the clinical application of TCM in IS prevention and treatment, as well as for the development of novel drugs.

15.
Dalton Trans ; 52(40): 14390-14399, 2023 Oct 17.
Artículo en Inglés | MEDLINE | ID: mdl-37781869

RESUMEN

Introducing sustainability into advanced catalytic material design is essential to address growing environmental concerns. Among them, synthesizing inorganic zeolite materials from non-traditional sources (like natural clay) offers several advantages, contributing to sustainability and environmental stewardship. With this objective, we used kaolin to synthesize zeolites with different topologies: SSZ-13 (8-MR with CHA topology), ZSM-5 (10-MR with MFI topology), and Beta (12-MR with BEA topology) (MR: member ring), where a simple and flexible synthetic protocol was adopted without any significant changes. All these zeolites were subjected to catalytic performance evaluation concerning the industrially relevant methanol-to-hydrocarbon (MTH) process. Herein, the kaolin-derived zeolites, especially ZSM-5, led to superior performance and demonstrated enhanced catalyst deactivation-resistant behavior compared to their zeolite counterparts prepared from traditional synthetic routes. Various characterization tools (including under operando conditions) were employed to understand their reactions and deactivation mechanisms. Overall, making zeolites from non-traditional sources presents a pathway for sustainable and environmentally friendly material production, offering benefits such as reduced resource dependence, lower energy consumption, and tailored physicochemical properties beneficial to catalysis. In a broader context, such a research approach contributes to the transition toward a more sustainable and circular economy.

16.
Heliyon ; 9(5): e15152, 2023 May.
Artículo en Inglés | MEDLINE | ID: mdl-37251840

RESUMEN

Angiogenesis plays a critical role in the survival, progression and metastasis of malignant tumors. Multiple factors are known to induce tumor angiogenesis, vascular endothelial growth factor (VEGF) is the most important one. Lenvatinib is an oral multi-kinase inhibitor of VEGFRs which has been approved for the treatment of various malignancies as the first-line agent by the Food and Drug Administration (FDA). It shows excellent antitumor efficacy in clinical practice. However, the adverse effects of Lenvatinib may seriously impair the therapeutic effect. Here we report the discovery and characterization of a novel VEGFR inhibitor (ZLF-095), which exhibited high activity and selectivity for VEGFR1/2/3. ZLF-095 displayed apparently antitumor effect in vitro and in vivo. We discovered that Lenvatinib could provoke fulminant ROS-caspase3-GSDME-dependent pyroptosis in GSDME-expressing cells by loss of mitochondrial membrane potential, which may be one of the reasons for Lenvatinib's toxicity. Meanwhile, ZLF-095 showed less toxicity than Lenvatinib by switching pyroptosis to apoptosis. These results suggest that ZLF-095 could become a potential angiogenesis inhibitor for cancer therapy.

17.
Commun Chem ; 6(1): 101, 2023 May 29.
Artículo en Inglés | MEDLINE | ID: mdl-37248368

RESUMEN

Water and its dissociated species at the solid‒liquid interface play critical roles in catalytic science; e.g., functions of oxygen species from water dissociation are gradually being recognized. Herein, the relationship between oxide identity (PtOHads, PtOads, and PtO2) and electrocatalytic activity of platinum for ethanol electrooxidation was obtained in perchlorate acidic solution over a wide potential range with an upper potential of 1.5 V (reversible hydrogen electrode, RHE). PtOHads and α-PtO2, rather than PtOads, act as catalytic centers promoting ethanol electrooxidation. This relationship was corroborated on Pt(111), Pt(110), and Pt(100) electrodes, respectively. A reaction mechanism of ethanol electrooxidation was developed with DFT calculations, in which platinum oxides-mediated dehydrogenation and hydrated reaction intermediate, geminal diol, can perfectly explain experimental results, including pH dependence of product selectivity and more active α-PtO2 than PtOHads. This work can be generalized to the oxidation of other substances on other metal/alloy electrodes in energy conversion and electrochemical syntheses.

18.
Environ Technol ; 44(17): 2631-2647, 2023 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-35113005

RESUMEN

The performance of granular activated carbon (GAC) loaded with different combinations of Fe, Co, Ni, Mn, and Ti was examined for the electrochemical degradation of an azo dye such as acid red B (AR-B). Among the bimetallic groups, the combination of Fe and Co exhibited the best degradation effect. X-ray diffraction and X-ray photoelectron spectroscopy revealed that the morphology of the catalyst is CoFe2O4, and scanning electron microscopy manifested that the catalyst is distributed on the GAC surface and holes. The initial pH, hydraulic retention time, and current intensively affected the decolourisation and degradation efficiencies of AR-B, while the electrolyte types and concentrations did not exert any considerable effect. Electron spin resonance spectroscopy indicated that strong signals of hydroxyl radicals are produced by the Fe-Co/GAC electrodes. Results from fluorescence spectroscopy and gas chromatography-mass spectrometry suggested that hydroxyl radicals preferentially attack azo bonds during the degradation of AR-B, forming a series of compounds, and these compounds are finally degraded into small molecules of organic acids, carbon dioxide, and water.


Asunto(s)
Compuestos Azo , Óxidos , Contaminantes Químicos del Agua , Compuestos Azo/química , Carbón Orgánico/química , Electrodos , Oxidación-Reducción , Óxidos/química , Espectroscopía de Fotoelectrones , Contaminantes Químicos del Agua/química
19.
Artículo en Inglés | MEDLINE | ID: mdl-35328958

RESUMEN

NH4+ is often produced during the electro-reduction of NO3-, which results in inadequate total nitrogen (TN) removal during advanced sewage treatment. In this study, the electro-reduction byproduct NH4+ was oxidized and removed using sulfate radical (SO4•-)-based advanced oxidation. Persulfate (PS) was activated by electrocatalysis, using Co/AC0.9-AB0.1 particle electrodes to produce SO4•-. Results showed that when the influent concentration of NO3--N was 20 mg/L, a PS dosage of 5.0 mM could completely oxidize NH4+ at 0.1 A (nondetectable in effluent) reducing the TN concentration from 9.22 to 0.55 mg/L. The presence of coexisting PO43-, CO32- and humic acid suppressed the oxidation and removal of NH4+. Electron spin resonance (ESR) spectra and quenching experiments revealed SO4•- as the dominant radical in the process of indirect NH4+ oxidation, while •OH radicals only had an assisting role, and the surface accumulated free radicals were responsible for the indirect oxidation of NH4+. Cyclic voltammetry (CV) curves indicated that NO3- was primarily reduced via atomic H*-mediated indirect reduction. Therefore, the activation of PS using Co/AC0.9-AB0.1 particle electrodes might be a promising alternative method for oxidizing byproduct NH4+ in the electro-reduction of NO3- and reduce TN concentration in advanced sewage treatment.


Asunto(s)
Amoníaco , Contaminantes Químicos del Agua , Nitratos , Nitrógeno , Óxidos de Nitrógeno , Compuestos Orgánicos , Oxidación-Reducción , Aguas del Alcantarillado
20.
J Phys Chem Lett ; 12(50): 12062-12066, 2021 Dec 23.
Artículo en Inglés | MEDLINE | ID: mdl-34908416

RESUMEN

The electrodissolution of Au(111) in anaerobic cupric/ammonia/thiosulfate solutions, typical of a non-equilibrium dissipative system, was investigated via in situ electrochemical atomic force microscopy. At a specific initial concentration ratio of aqueous ammonia to cupric ions, the pit number and average pit area increase autocatalytically, while the pit depth increases monotonically during dissolution. A further increase in this initial concentration ratio leads to oscillatory dynamics in the pit number and average pit area while the pit depth fluctuates between one and two atoms. Mechanistic analysis indicates that alternation between formation and dissolution of a sulfur film results in periodic pitting, which produces gold dissolution layer by layer. This work presents a new dissolution mode, i.e., periodic layer dissolution generated by oscillatory pitting processes in addition to a pitting mode with a continually increasing depth, and the use of high initial concentration ratios of ammonia to cupric ion to accelerate the elimination of passivating sulfur film for Au dissolution.

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