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1.
J Chromatogr A ; 1648: 462189, 2021 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-33975082

RESUMO

Ce-doped Fe3O4 magnetic particles (Ce-Fe3O4 MPs) were synthesized by co-precipitation method. The coordination and adsorption properties of Ce-Fe3O4 MPs to different natural products were investigated. The results verified that the "catechol-like","maltol-like" and "acetylacetone-like" donor sets of flavonoids were the binding sites with Ce-Fe3O4 MPs. The adsorption was conformed to be pseudo-second-order model and single-layer adsorption after being characterized by adsorption kinetics and adsorption thermodynamics. The adsorption and desorption conditions were optimized. It was found that different components adsorbed on the Ce-Fe3O4 MPs surface can be selective desorbed in different solvents, which was helpful for the selective separation to adsorbed components. The Ce-Fe3O4 MPs were successfully applied to selective adsorption of compounds containing "catechol-like", "maltol-like" and "acetylacetone-like" donor sets in the crude extract of Scutellaria baicalensis Georgi and Rheum palmatum L. The results demonstrated that the magnetic solid phase extraction (MSPE) method based on Ce-Fe3O4 MPs has the advantages of high structural selectivity, high efficiency and low consumption, and can be used for efficient separation of flavonoids with specific structures from natural products.


Assuntos
Cério/química , Compostos Férricos/química , Flavonoides/química , Adsorção , Cinética , Ligantes , Fenômenos Magnéticos , Magnetismo , Extração em Fase Sólida/métodos , Solventes/química
2.
Nat Commun ; 12(1): 1436, 2021 03 04.
Artigo em Inglês | MEDLINE | ID: mdl-33664241

RESUMO

Acute kidney injury (AKI) is a prevalent and lethal adverse event that severely affects cancer patients receiving chemotherapy. It is correlated with the collateral damage to renal cells caused by reactive oxygen species (ROS). Currently, ROS management is a practical strategy that can reduce the risk of chemotherapy-related AKI, but at the cost of chemotherapeutic efficacy. Herein, we report catalytic activity tunable ceria nanoparticles (CNPs) that can prevent chemotherapy-induced AKI without interference with chemotherapeutic agents. Specifically, in the renal cortex, CNPs exhibit catalytic activity that decomposes hydrogen peroxide, and subsequently regulate the ROS-involved genes by activating the Nrf2/Keap1 signaling pathway. These restore the redox homeostasis for the protection of kidney tubules. Under an acidic tumor microenvironment, CNPs become inert due to the excessive H+ that disrupts the re-exposure of active catalytic sites, allowing a buildup of chemotherapy-mediated ROS generation to kill cancer cells. As ROS-modulating agents, CNPs incorporated with context-dependent catalytic activity, hold a great potential for clinical prevention and treatment of AKI in cancer patients.


Assuntos
Injúria Renal Aguda/prevenção & controle , Antineoplásicos/efeitos adversos , Cério/farmacologia , Túbulos Renais/patologia , Espécies Reativas de Oxigênio/metabolismo , Células A549 , Animais , Antineoplásicos/uso terapêutico , Domínio Catalítico , Linhagem Celular Tumoral , Cério/química , Feminino , Células Hep G2 , Humanos , Proteína 1 Associada a ECH Semelhante a Kelch/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Fator 2 Relacionado a NF-E2/genética , Fator 2 Relacionado a NF-E2/metabolismo , Nanopartículas/química , Neoplasias/tratamento farmacológico , Oxirredução , Estresse Oxidativo/efeitos dos fármacos , Interferência de RNA , RNA Interferente Pequeno/genética , Transdução de Sinais/efeitos dos fármacos , Microambiente Tumoral
3.
Molecules ; 26(4)2021 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-33562554

RESUMO

Waste lignin is a potential source of renewable fuels and other chemical precursors under catalytic pyrolysis. For this purpose, four mixed metal oxide catalytic mixtures (Cat) derived from Na2CO3, CeO2 and ZrO2 were synthesised in varying compositions and utilised in a fixed bed reactor for catalytic vapour upgrading of Etek lignin pyrolysis products at 600 °C. The catalytic mixtures were analysed and characterised using XRD analysis, whilst pyrolysis products were analysed for distribution of products using FTIR, GC-MS and EA. Substantial phenolic content (20 wt%) was obtained when using equimolar catalytic mixture A (Cat_A), however the majority of these phenols were guaiacol derivatives, suggesting the catalytic mixture employed did not favour deep demethoxylation. Despite this, addition of 40-50% ceria to NaZrO2 resulted in a remarkable reduction of coke to 4 wt%, compared to ~9 wt% of NaZrO2. CeO2 content higher than 50% favoured the increase in conversion of the holo-cellulose fraction, enriching the bio-oil in aldehydes, ketones and cyclopentanones. Of the catalytic mixtures studied, equimolar metal oxides content (Cat_A) appears to showcase the optimal characteristics for phenolics production and coking reduction.


Assuntos
Cério/química , Lignina/química , Óxidos/química , Pirólise , Compostos de Sódio/química , Resíduos/análise , Zircônio/química , Catálise , Fenol/química
4.
Molecules ; 26(4)2021 Feb 03.
Artigo em Inglês | MEDLINE | ID: mdl-33546465

RESUMO

A novel double-decker porphyrin complex, bis{meso-tetrakis(4-N-alkylpyridiniumyl)porphyrinato}cerium, was prepared. Electrochemical measurements revealed that this complex exhibited reversible redox waves corresponding to a 1e- redox reaction of the cerium center. Treating the complex alternately with an oxidant and a reductant resulted in the reversible redox switching between the oxidized and reduced states in an organic solvent.


Assuntos
Cério/química , Metaloporfirinas/química , Metaloporfirinas/síntese química , Modelos Moleculares , Oxirredução
5.
J Agric Food Chem ; 69(3): 1115-1122, 2021 Jan 27.
Artigo em Inglês | MEDLINE | ID: mdl-33450153

RESUMO

The increasing prevalence of products that incorporate engineered nanoparticles (ENPs) has prompted efforts to investigate the potential release, environmental fate, and exposure of the ENPs. However, the investigation of cerium dioxide nanoparticles (CeO2 NPs) in soil has remained limited, owing to the analytical challenge from the soil's complex nature. In this study, this challenge was overcome by applying a novel single particle-inductively coupled plasma-mass spectrometry (SP-ICP-MS) methodology to detect CeO2 NPs extracted from soil, utilizing tetrasodium pyrophosphate (TSPP) aqueous solution as an extractant. This method is highly sensitive for determining CeO2 NPs in soil, with detection limits of size and concentration of 15 nm and 194 NPs mL-1, respectively. Extraction efficiency was sufficient in the tested TSPP concentration range from 1 mM to 10 mM at a soil-to-extractant ratio 1:100 (g mL-1) for the extraction of CeO2 NPs from the soil spiked with CeO2 NPs. The aging study demonstrated that particle size, size distribution, and particle concentration underwent no significant change in the aged soils for a short period of one month. This study showed an efficient method capable of extracting and accurately determining CeO2 NPs in soil matrices. The method can serve as a useful tool for nanoparticle analysis in routine soil tests and soil research.


Assuntos
Cério/química , Espectrometria de Massas/métodos , Nanopartículas/química , Poluentes do Solo/química , Tamanho da Partícula , Sensibilidade e Especificidade , Solo/química
6.
ACS Appl Mater Interfaces ; 13(1): 233-244, 2021 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-33373178

RESUMO

Photodynamic therapy (PDT) and photothermal therapies (PTTs) are both promising strategies for effective tumor therapy. However, the absence of O2 at tumor sites hinders the sustained response of photosensitizers. Here, we develop a recycled cerium oxide (CeO2) catalase nanozyme-loaded hyaluronic acid nanovesicle to address the hypoxic tumor microenvironments and targeted delivery of the photosensitizers [indocyanine green (ICG)] to tumors. A polysaccharide complex effectively modifies the surface of a polyethylenimine phenylboronic acid nanostructure to achieve the CeO2 nanozyme-loading nanovesicles that exhibit both tumor-targeted enhancement and an improved hypoxic microenvironment. Also, the hydrogen peroxide responsiveness and acid-sensitive cleavage of phenylboronic acid specifically disintegrate the ICG/nanozyme coloaded nanovesicles in the tumor microenvironment. The in vitro synergistic tests and tumor suppression rate tests indicated that the cerium oxide nanozyme significantly improves the outcomes of PDT via cerium-element valence state recycling and hypoxia improvement, thus enhancing the tumor suppression efficiency. This pH/H2O2-responsive nanozyme/ICG codelivery system provides a good carrier model for improving the tumor microenvironment and increasing the efficiency of tumor-targeted PTT and PDT therapies.


Assuntos
Antineoplásicos/uso terapêutico , Cério/uso terapêutico , Verde de Indocianina/uso terapêutico , Nanopartículas/química , Neoplasias/tratamento farmacológico , Fármacos Fotossensibilizantes/uso terapêutico , Animais , Catálise , Linhagem Celular Tumoral , Cério/química , Cério/toxicidade , Feminino , Humanos , Ácido Hialurônico/química , Ácido Hialurônico/toxicidade , Peróxido de Hidrogênio , Concentração de Íons de Hidrogênio , Raios Infravermelhos , Camundongos Endogâmicos BALB C , Nanopartículas/toxicidade , Neoplasias/metabolismo , Fotoquimioterapia , Terapia Fototérmica , Espécies Reativas de Oxigênio/metabolismo , Microambiente Tumoral/efeitos dos fármacos
7.
Nat Chem ; 13(3): 284-289, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33318671

RESUMO

Developing targeted α-therapies has the potential to transform how diseases are treated. In these interventions, targeting vectors are labelled with α-emitting radioisotopes that deliver destructive radiation discretely to diseased cells while simultaneously sparing the surrounding healthy tissue. Widespread implementation requires advances in non-invasive imaging technologies that rapidly assay therapeutics. Towards this end, positron emission tomography (PET) imaging has emerged as one of the most informative diagnostic techniques. Unfortunately, many promising α-emitting isotopes such as 225Ac and 227Th are incompatible with PET imaging. Here we overcame this obstacle by developing large-scale (Ci-scale) production and purification methods for 134Ce. Subsequent radiolabelling and in vivo PET imaging experiments in a small animal model demonstrated that 134Ce (and its 134La daughter) could be used as a PET imaging candidate for 225AcIII (with reduced 134CeIII) or 227ThIV (with oxidized 134CeIV). Evaluating these data alongside X-ray absorption spectroscopy results demonstrated how success relied on rigorously controlling the CeIII/CeIV redox couple.


Assuntos
Cério/química , Lantânio/química , Tomografia por Emissão de Pósitrons , Compostos Radiofarmacêuticos/química , Abdome/diagnóstico por imagem , Animais , Radioisótopos de Cério/química , Oxirredução , Compostos Radiofarmacêuticos/metabolismo , Distribuição Tecidual
8.
Chemosphere ; 262: 128215, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33182126

RESUMO

The effluent from conventional treatment process (including anaerobic digestion and anoxic-oxic treatment) for pig farm wastewater was difficult to treat due to its low ratio of biochemical oxygen demand to chemical oxygen demand (BOD5/CODCr) (<0.1). In the present study, electro-Fenton (EF) was used to improve the biodegradability of the mentioned effluent and the properties of self-prepared CeO2-doped multi-wall carbon nanotubes (MWCNTs) electrodes were also studied. An excellent H2O2 production (165 mg L-1) was recorded, after an 80-min electrolysis, when the mass ratio of MWCNTs, CeO2 and pore-forming agent (NH4HCO3) was 6:1:1. Results of scanning electron microscopy (SEM), transmission electron microscope (TEM) and x-ray photoelectron spectroscopy (XPS) showed that addition of NH4HCO3 and the doping of CeO2 could increase the superficial area of the electrode as well as the oxygen reduction reaction (ORR) electro-catalytic performance. The BOD5/CODCr of the wastewater from the first stage AO process increased from 0.08 to 0.45 and CODCr reduced 71.5% after an 80-min electrolysis, with 0.3 mM Fe2+ solution. The non-biodegradable chemical pollutants from the first stage AO process were degraded by EF. The non-biodegradable pollutants identified by LC-MS/MS in the effluent from AO process including aminopyrine, oxadixyl and 3-methyl-2-quinoxalinecarboxylic acid could be degraded by EF process, with the removal rates of 81.86%, 34.39% and 7.13% in 80 min, and oxytetracycline with the removal rate of 100% in 20 min. Therefore, electro-Fenton with the new CeO2-doped MWCNTs cathode electrode will be a promising supplement for advanced treatment of pig farm wastewater.


Assuntos
Cério/química , Eletrólise/métodos , Nanotubos de Carbono/química , Águas Residuárias/química , Poluentes Químicos da Água/análise , Purificação da Água/métodos , Animais , Biodegradação Ambiental , Análise da Demanda Biológica de Oxigênio , Catálise , Eletrodos , Fazendas , Peróxido de Hidrogênio/análise , Oxirredução , Suínos
9.
Nanotechnology ; 32(2): 025504, 2021 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-32932238

RESUMO

Self-assembled hierarchical nanostructures are slowly superseding their conventional counterparts for use in biosensors. These morphologies show high surface area with tunable porosity and packing density. Modulating the interfacial interactions and subsequent particle assembly occurring at the water-and-oil interface in inverse miniemulsions, are amongst the best strategies to stabilize various type of hollow nanostructures. The paper presents a successful protocol to obtain CeO2 hollow structures based biosensors that are useful for glucose to protein sensing. The fabricated glucose sensor is able to deliver high sensitivity (0.495 µA cm-2 nM-1), low detection limit (6.46 nM) and wide linear range (0 nM to 600 nM). CeO2 based bioelectrode can also be considered as a suitable candidate for protein sensors. It can detect protein concentrations varying from 0 to 30 µM, which is similar or higher than most reports in the literature. The limit of detection (LOD) for protein was ∼0.04 µM. Therefore, the hollow CeO2 electrodes, with excellent reproducibility, stability and repeatability, open a new area of application for cage-frame type particles.


Assuntos
Cério/química , Glucose/análise , Nanoestruturas/química , Proteínas/análise , Técnicas Biossensoriais/métodos , Técnicas Eletroquímicas/métodos , Eletrodos , Humanos , Limite de Detecção , Oxirredução
10.
ACS Appl Mater Interfaces ; 12(51): 56830-56838, 2020 Dec 23.
Artigo em Inglês | MEDLINE | ID: mdl-33319561

RESUMO

Rhabdomyolysis-induced acute kidney injury (AKI) is closely related to abundant reactive oxygen species (ROS). Owing to the multi-enzymatic activity and broad-spectrum ROS scavenging capacity of ceria nanoparticles (ceria NPs), herein, we report ultrasmall citric acid modified ceria nanozymes (3-4 nm) as antioxidants to alleviate rhabdomyolysis-induced AKI through removing excessive ROS. The as-prepared ceria NPs exhibited multi-enzymatic properties such as peroxidase, catalase, and superoxide dismutase, offering efficient protection of renal cells against H2O2 stimulation in vitro. Moreover, due to their ultrasmall size, ceria NPs could efficiently accumulate in the kidneys, thus protecting renal cells against ROS in vivo. Our results present ultrasmall ceria nanozymes as antioxidants for rhabdomyolysis-induced AKI alleviation, which shows great potential in clinic.


Assuntos
Injúria Renal Aguda/prevenção & controle , Cério/uso terapêutico , Sequestradores de Radicais Livres/uso terapêutico , Nanopartículas Metálicas/uso terapêutico , Animais , Catálise , Cério/química , Cério/farmacocinética , Cério/toxicidade , Sequestradores de Radicais Livres/química , Sequestradores de Radicais Livres/farmacocinética , Sequestradores de Radicais Livres/toxicidade , Células HEK293 , Humanos , Rim/efeitos dos fármacos , Rim/patologia , Nanopartículas Metálicas/química , Nanopartículas Metálicas/toxicidade , Camundongos , Espécies Reativas de Oxigênio/metabolismo
11.
Int J Nanomedicine ; 15: 7199-7214, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33061376

RESUMO

The ongoing biomedical nanotechnology has intrigued increasingly intense interests in cerium oxide nanoparticles, ceria nanoparticles or nano-ceria (CeO2-NPs). Their remarkable vacancy-oxygen defect (VO) facilitates the redox process and catalytic activity. The verification has illustrated that CeO2-NPs, a nanozyme based on inorganic nanoparticles, can achieve the anti-inflammatory effect, cancer resistance, and angiogenesis. Also, they can well complement other materials in tissue engineering (TE). Pertinent to the properties of CeO2-NPs and the pragmatic biosynthesis methods, this review will emphasize the recent application of CeO2-NPs to orthopedic biomedicine, in particular, the bone tissue engineering (BTE). The presentation, assessment, and outlook of the orthopedic potential and shortcomings of CeO2-NPs in this review expect to provide reference values for the future research and development of therapeutic agents based on CeO2-NPs.


Assuntos
Tecnologia Biomédica , Cério/química , Nanopartículas/química , Ortopedia , Humanos , Nanotecnologia , Próteses e Implantes
12.
Int J Nanomedicine ; 15: 6355-6372, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32922006

RESUMO

Background: Cerium oxide nanoparticles (CeO2NPs) are potent scavengers of cellular reactive oxygen species (ROS). Their antioxidant properties make CeO2NPs promising therapeutic agents for bone diseases and bone tissue engineering. However, the effects of CeO2NPs on intracellular ROS production in osteoclasts (OCs) are still unclear. Numerous studies have reported that intracellular ROS are essential for osteoclastogenesis. The aim of this study was to explore the effects of CeO2NPs on osteoclast differentiation and the potential underlying mechanisms. Methods: The bidirectional modulation of osteoclast differentiation by CeO2NPs was explored by different methods, such as fluorescence microscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), quantitative real-time polymerase chain reaction (qRT-PCR), and Western blotting. The cytotoxic and proapoptotic effects of CeO2NPs were detected by cell counting kit (CCK-8) assay, TdT-mediated dUTP nick-end labeling (TUNEL) assay, and flow cytometry. Results: The results of this study demonstrated that although CeO2NPs were capable of scavenging ROS in acellular environments, they facilitated the production of ROS in the acidic cellular environment during receptor activator of nuclear factor kappa-Β ligand (RANKL)-dependent osteoclast differentiation of bone marrow-derived macrophages (BMMs). CeO2NPs at lower concentrations (4.0 µg/mL to 8.0 µg/mL) promoted osteoclast formation, as shown by increased expression of Nfatc1 and C-Fos, F-actin ring formation and bone resorption. However, at higher concentrations (greater than 16.0 µg/mL), CeO2NPs inhibited osteoclast differentiation and promoted apoptosis of BMMs by reducing Bcl2 expression and increasing the expression of cleaved caspase-3, which may be due to the overproduction of ROS. Conclusion: This study demonstrates that CeO2NPs facilitate osteoclast formation at lower concentrations while inhibiting osteoclastogenesis in vitro by inducing the apoptosis of BMMs at higher concentrations by modulating cellular ROS levels.


Assuntos
Diferenciação Celular , Cério/química , Osteoclastos/citologia , Espécies Reativas de Oxigênio/metabolismo , Actinas/metabolismo , Animais , Apoptose/efeitos dos fármacos , Apoptose/genética , Células da Medula Óssea/citologia , Células da Medula Óssea/efeitos dos fármacos , Reabsorção Óssea/metabolismo , Diferenciação Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Regulação para Baixo/efeitos dos fármacos , Regulação da Expressão Gênica/efeitos dos fármacos , Macrófagos/citologia , Macrófagos/efeitos dos fármacos , Macrófagos/ultraestrutura , Masculino , Camundongos Endogâmicos C57BL , NF-kappa B/metabolismo , Nanopartículas/ultraestrutura , Osteoclastos/efeitos dos fármacos , Osteogênese/efeitos dos fármacos , Ligante RANK/farmacologia , Transdução de Sinais/efeitos dos fármacos , Regulação para Cima/efeitos dos fármacos
13.
Nucleic Acids Res ; 48(17): 9986-9994, 2020 09 25.
Artigo em Inglês | MEDLINE | ID: mdl-32853337

RESUMO

Telomeric DNA, whose length homeostasis is closely correlated with immortality of cancer cells, is regarded as a molecular clock for cellular lifespan. Regarding the capacity in forming G-quadruplex, G-rich 3'-overhang (G-overhang) has been considered as an attractive anticancer target. However, it is still challenging to precisely target telomeric G-overhang with current ligands because of the polymorphism of G-quadruplexes in cells. Herein, we construct a telomeric G-overhang-specific near-infrared-traceable DNA nano-hydrolase, which is composed of four parts: (i) dexamethasone for targeting cell nuclei; (ii) complementary DNA for hybridizing with G-overhang; (iii) multinuclear Ce(IV) complexes for hydrolyzing G-overhang; and (iv) upconversion nanoparticles for real-time tracking. The multivalent targeted DNA nano-hydrolase can be traced to precisely digest telomeric G-overhang, which contributes to telomeric DNA shortening and thereby causes cell aging and apoptosis. The anticancer treatment is further proved by in vivo studies. In this way, this design provides a telomeric G-overhang-specific eradication strategy based on a non-G-quadruplex targeting manner.


Assuntos
Antineoplásicos/farmacologia , Nanopartículas/química , Neoplasias Experimentais/tratamento farmacológico , Compostos Organometálicos/farmacologia , Telômero/efeitos dos fármacos , Animais , Antineoplásicos/administração & dosagem , Antineoplásicos/uso terapêutico , Cério/química , Dexametasona/química , Quadruplex G , Humanos , Hidrólise , Células MCF-7 , Camundongos , Nanopartículas/metabolismo , Compostos Organometálicos/administração & dosagem , Compostos Organometálicos/uso terapêutico , Telômero/química
14.
Int J Nanomedicine ; 15: 5951-5961, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32848398

RESUMO

During the last decade green synthesized cerium oxide nanoparticles (CeO2 NPs) attracted remarkable interest in various fields of science and technology. This review, explores the vast array of biological resources such as plants, microbes, and other biological products being used in synthesis of CeO2 NPs. It also discusses their biosynthetic mechanism, current understandings, and trends in the green synthesis of CeO2 NPs. Novel therapies based on green synthesized CeO2 NPs are illustrated, in particular their antimicrobial potential along with attempts of their mechanistic elucidation. Overall, the main objective of this review is to provide a rational insight of the major accomplishments of CeO2 NPs as novel therapeutics agents for a wide range of microbial pathogens and combating other diseases.


Assuntos
Anti-Infecciosos/síntese química , Anti-Infecciosos/farmacologia , Cério/química , Nanopartículas Metálicas/química , Antibacterianos/síntese química , Antibacterianos/farmacologia , Química Verde , Extratos Vegetais/química
15.
Chemosphere ; 259: 127488, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32640376

RESUMO

A Ce-doped Ti/PbO2 electrode was prepared in a deposition solution containing Ce3+ and Pb2+ ions by electrodeposition, and the surface morphology, crystal structure and elemental states were characterized by SEM, XRD and XPS. The electrode was used to investigate the simultaneous degradation of three phthalate esters (PAEs), i.e., dimethyl phthalate (DMP), diethyl phthalate (DEP) and dibutyl phthalate (DBP) in synthetic wastewaters. The results showed that the electrode exhibited excellent electrocatalytic activity and good reusability and stability, and the removal efficiencies of 5 mg L-1 DBP, DMP and DEP in 0.05 M Na2SO4 (pH 7) reached 98.2%, 95.8% and 81.1% at current density of 25 mA cm-2 after 10 h degradation, respectively. The degradation processes followed pseudo first-order kinetic model very well, and the observed rate constants of DBP, DEP and DMP were 0.42, 0.40 and 0.29 h-1, respectively. The energy consumption in three PAEs degradation was also assessed. The main degradation products of the three PAEs were identified by using liquid chromatography-tandem mass spectrometry, and the possible degradation pathways mainly included dealkylation, hydroxyl addition, decarboxylation and benzene ring cleavage. This work is a promising candidate for efficient treatment of multiple PAEs in wastewater and protection of the aquatic ecological environment.


Assuntos
Cério/química , Galvanoplastia/métodos , Recuperação e Remediação Ambiental/métodos , Ácidos Ftálicos/química , Águas Residuárias/química , Poluentes Químicos da Água/química , Dibutilftalato/química , Eletrodos , Ésteres/química , Chumbo/química , Óxidos/química , Titânio/química
16.
Chemosphere ; 261: 127739, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32717516

RESUMO

Copper/cerium bimetallic catalyst is an efficient material for the removal of carbon monoxide, while the rapid deactivation under moisture-rich conditions in the conventional thermal-catalysis limited its wide application. Here, we investigated the plasma-assisted catalytic oxidation of CO over Cu/Ce oxides supported on γ-Alumina in comparison with the conventional thermal catalytic oxidation. The TOF values of the Cu/Ce catalysts showed that the plasma catalysis was the better catalytic system for CO oxidation (2.96 s-1 for thermal catalysis, 5.13 s-1 for plasma catalysis). Importantly, the energy barriers for plasma catalysis were much lower than that for thermal catalysis, especially under moisture-rich conditions (e.g. 130.3 kJ/mol versus 246.1 kJ/mol under 9.8 vol% water vapor). The loss of activity caused by water was reversible for the plasma process, but not for the thermal process. The Cu/Ce catalyst remained good stability within 60 h in the presence of 6.1% water for plasma oxidation, while the thermal catalytic activity declines gradually. Also, water could inhibit the formation of gas byproducts (O3 and NOx). The promoting role of plasma could be mainly ascribed to the enhanced strength of oxygen mobility and plasma-assisted decomposition of surface carbonate in the presence of water, as revealed by the in-situ NTP-TPR, XPS, and the ex-situ DRIFTS analyses.


Assuntos
Monóxido de Carbono/química , Cério/química , Cobre/química , Catálise , Oxirredução , Óxidos/química , Oxigênio/química , Água/química
17.
Chemosphere ; 258: 127334, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32540536

RESUMO

Herein, MgO cathode and graphene Mn-Ce bimetallic oxide were utilized to jointly enhance the removal of toluene in pulsed discharge plasma (PDP). Compared to the common cathode, the MgO cathode enhanced the density of high energy electrons, and then induced to higher removal of toluene. However, the removal of toluene by PDP/MgO system was still insufficient, and there was a large amount of underutilized O3 in the products. Based on this, Mn-Ce/graphene catalysts were introduced into PDP/MgO system. The Mn-Ce (8:1)/graphene catalyst had the highest catalytic activity. Under the discharge power of 2.1 W, toluene degradation rate and CO2 selectivity increased by 27.5% and 22.0%, respectively. This was ascribed to the synergistic effect of the solid solution formed between MnOx and CeOx, increasing the proportion of Oads on the surface of the catalyst. The higher Oads/Olatt ratio lead to the better catalytic activity, which was conducive to the complete transformation of the intermediate products to CO2 and H2O. According to the detected products, the degradation pathway and the mechanism of toluene degradation were proposed finally. The PDP itself, field emission effect of MgO cathode and catalytic effect of Mn-Ce/graphene for jointly improve the toluene removal and CO2 selectivity.


Assuntos
Técnicas Eletroquímicas/métodos , Grafite/química , Óxido de Magnésio/química , Tolueno/isolamento & purificação , Dióxido de Carbono , Catálise , Cério/química , Eletrodos , Compostos de Manganês/química , Óxidos/química , Água
18.
Nanotoxicology ; 14(6): 827-846, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32552239

RESUMO

Prior studies showed nanoparticle clearance was different in C57BL/6 versus BALB/c mice, strains prone to Th1 and Th2 immune responses, respectively. Objective: Assess nanoceria (cerium oxide, CeO2 nanoparticle) uptake time course and organ distribution, cellular and oxidative stress, and bioprocessing as a function of mouse strain. Methods: C57BL/6 and BALB/c female mice were i.p. injected with 10 mg/kg nanoceria or vehicle and terminated 0.5 to 24 h later. Organs were collected for cerium analysis; light and electron microscopy with elemental mapping; and protein carbonyl, IL-1ß, and caspase-1 determination. Results: Peripheral organ cerium significantly increased, generally more in C57BL/6 mice. Caspase-1 was significantly elevated in the liver at 6 h, to a greater extent in BALB/c mice, suggesting inflammasome pathway activation. Light microscopy revealed greater liver vacuolation in C57BL/6 mice and a nanoceria-induced decrease in BALB/c but not C57BL/6 mice vacuolation. Nanoceria increased spleen lymphoid white pulp cell density in BALB/c but not C57BL/6 mice. Electron microscopy showed intracellular nanoceria particles bioprocessed to form crystalline cerium phosphate nanoneedles. Ferritin accumulation was greatly increased proximal to the nanoceria, forming core-shell-like structures in C57BL/6 but even distribution in BALB/c mice. Conclusions: BALB/c mice were more responsive to nanoceria-induced effects, e.g. liver caspase-1 activation, reduced liver vacuolation, and increased spleen cell density. Nanoceria uptake, initiation of bioprocessing, and crystalline cerium phosphate nanoneedle formation were rapid. Ferritin greatly increased with a macrophage phenotype-dependent distribution. Further study will be needed to understand the mechanisms underlying the observed differences.


Assuntos
Cério/toxicidade , Fígado/efeitos dos fármacos , Nanopartículas/toxicidade , Estresse Oxidativo/efeitos dos fármacos , Baço/efeitos dos fármacos , Animais , Cério/química , Cério/metabolismo , Feminino , Fígado/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Microscopia Eletrônica , Nanopartículas/química , Nanopartículas/metabolismo , Fosfatos/metabolismo , Especificidade da Espécie , Baço/metabolismo , Propriedades de Superfície , Distribuição Tecidual
19.
Chemosphere ; 257: 127215, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32505950

RESUMO

Red mud, as industrial solid waste, causes severe environmental problems such as soil alkalization and groundwater pollution. In this work, we researched and developed the red mud as a selective catalytic reduction catalyst for NOx removal with NH3 (NH3-SCR). After selective dissolution and specific heat treatment, different Ce precursors were used to modifying its physical and chemical properties. The results showed that Ce(NO3)3 and Ce(NH4)2(NO3)6 modified red mud (RMcn and RMcan) had excellent SCR performance below 300 °C. Ce(SO4)2 modified red mud (RMcs) showed relatively low NOx conversions at 200-300 °C. The redox property was improved with the Ce(NO3)3 and Ce(NH4)2(NO3)6, while depressed with the Ce(SO4)2. Agglomerates generated on the RMcs and blocked the accumulated pores due to the formation of Ce2(SO4)3. The surface acidity of RMcs enhanced with increased adsorption for ammonia. However, these new adsorbed ammonia species, highly related to the sulfate from the Ce2(SO4)3, were inert and did not react with the adsorbed or gaseous NO species at 200-300 °C. The abundant surface lattice oxygen from CeO2 microcrystals improved the catalytic oxidation capacity of the RMcn and RMcan.


Assuntos
Cério/química , Adsorção , Amônia/química , Catálise , Óxidos de Nitrogênio , Oxirredução , Óxidos/química , Oxigênio , Sulfatos/química , Propriedades de Superfície
20.
Chemosphere ; 256: 127056, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32447108

RESUMO

Trivalent cerium (Ce(Ⅲ)) was demonstrated to have great potential for phosphate (P) removal. Besides the valence states, the relationship of nano-structure and adsorption capacity needs further study to explore more efficient adsorbents. Herein, a series of Ce(Ⅲ)-terephthalate (BDC) metal-organic framework (MOF) with linker deficiencies are fabricated to achieve excellent P capture. The defective density can be increased by decreasing the reaction time and the ratio of organic linkers/metal. TGA reveals Ce-BDC-48 synthesized with BDC:Ce ratio of 1:1 for 48 h possessed 2.5 missing linkers per inorganic node. And the P uptake of Ce-BDC-48 was 35% higher than that of Ce-BDC-72 without defects. The maximum adsorption capacity of Ce-BDC-48 was 278.8 mg/g for P and 128.0 mg/g for fluoride (F), respectively. The adsorption mechanism illustrates that both P and F mainly focus on the Ce(Ⅲ) active sites to achieve ligand exchange. The competing adsorption of P and F at the lower concentration of F (50 mg/L) indicates that the interference of F for P removal is insignificant on account of the selective preferential order of P. However, with the increment of F concentration (100 mg/L), amount of F with small sizes gathering around the adsorbent surface enlarge the steric hindrance to hinder the access of P, leading to the sharp decline of P uptake. This study not only provides promising candidate by the design of structural defects for the P removal in practical application but also give a deep analysis on the adsorption mechanism of P with competing F surrounded.


Assuntos
Cério/química , Fluoretos/química , Fosfatos/química , Poluentes Químicos da Água/química , Adsorção
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