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1.
Chemosphere ; 240: 124928, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31563101

RESUMO

Oxidation is an attractive treatment method to effectively remove organic contaminants in water. In this study, degradation of 30 organic compounds in different oxidation systems was evaluated, including oxygen (O2), hydrogen peroxide (H2O2), ozone (O3) and hydroxyl radical (HO). First, a quantitative structure-activity relationship (QSAR) model for oxidation-reduction potentials (ORPs) of organics was developed and exhibited a good performance to predict ORP values of organics with evaluation indices of squared correlation coefficient (R2) = 0.866, internal validation (q2) = 0.811 and external validation (Qext2) = 0.669. Four quantum parameters, including f(+)n, f(-)n, EHOMO and EB3LYP dominate the ORP values. Subsequently, a relationship between reaction rates (k) and the difference of ORP for oxidants and organics (ΔEoxi-org) was established, however, which was limited (R2= 0.697). Therefore, two new predictors (slopes and intercepts) are proposed based on the linear relationships between k values and ORPs of oxidants. These new predictors can be applied to estimate the reaction rates and minimum oxidation potential for organic compounds. Afterwards, to express the two predictors, QSAR models were established. The two optimal QSAR models fitted very well with experimental values and were demonstrated to be stable and accurate based on R2 (0.982 and 0.965), q2 (0.950 and 0.950) and Qext2 (0.985 and 0.989). BOx, q(H)+ and q(C)x were main factors influencing the slopes and intercepts. This study developed methods to predict ORPs of organics and established two new predictors to estimate the reaction rates undergoing different oxidation processes, offering new insights into the oxidant selection.


Assuntos
Modelos Teóricos , Compostos Orgânicos/análise , Relação Quantitativa Estrutura-Atividade , Poluentes Químicos da Água/análise , Purificação da Água/métodos , Peróxido de Hidrogênio/química , Radical Hidroxila/química , Oxidantes/química , Oxirredução , Oxigênio/química , Ozônio/química , Águas Residuárias/química , Água
2.
Chemosphere ; 239: 124763, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31526989

RESUMO

Nonredox metal ions have been widely recognized to be important in a wide range of biological and chemical oxidations as Lewis acids (LA). However, the role of LA in peroxymonosulfate (PMS) activation for wastewater treatment has not been considered until now. This study shows that oxidizing power of PMS can be promoted after binding nonredox metal ions such as Ca2+ as LA, leading to the easier reduction of the oxidant to radicals and substantial enhancement of dye degradation by employing manganese oxides OMS-2 as model catalysts. Increased with Lewis acidity of the metal ion, the rate of PMS decomposition enhanced linearly, while the dye degradation rate first increased and then declined due to the formation of a larger amount of dioxygen. The interactions between Ca2+ and PMS were further investigated by Raman, cyclic voltammetry and XPS; and the detailed mechanism of PMS activation was proposed. The performance of Ca2++OMS-2/PMS system under different conditions was also studied. The findings indicate the importance of LA in PMS activation reaction and their role must be considered in other transition metal oxides/PMS systems. It will be also helpful to design new and highly active catalysts for the reactions.


Assuntos
Ácidos de Lewis/química , Compostos de Manganês/química , Óxidos/química , Peróxidos/química , Poluentes Químicos da Água/química , Cálcio/química , Catálise , Corantes/química , Oxidantes/química , Oxirredução , Soluções , Eliminação de Resíduos Líquidos/métodos , Águas Residuárias/química
3.
Chemosphere ; 238: 124575, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31446274

RESUMO

Significance of surface and ground water contamination by synthetic organic compounds has been pointed out in a very high number of papers worldwide, as well as the need of application of treatment technologies capable to assure their complete removal. Among these processes, the electrochemical advanced oxidation is an interesting option, especially when irradiated with UVC light (photo-electrochemical, P-EC) to promote homolysis of electrogenerated oxidants. In this work, the herbicide glyphosate (GLP) was used as model compound and it was electrochemically treated under UVC irradiation in the presence of NaCl and using a DSA® and BDD anodes. Total organic carbon concentration was measured throughout the electrolysis, as well as the concentration of short chain carboxylic acids and inorganic ions (NO3-, PO43-,ClO-, ClO3- and ClO4-). The synergism of the P-EC was more pronounced when using a DSA® electrode, which led to complete GLP mineralization in 1 h (0.52 A h L-1), as also confirmed by the stoichiometric formation of NO3- and PO43- ions, with an energy consumption as low as 1.25 kW h g-1. Unexpectedly, the concentration evolution of oxyhalides for the P-EC process using both anodes, especially for DSA® at 10 mA cm-2, showed the production of ClO3-, whereas detection of ClO4- species was only found when using BDD at 100 mA cm-2 for the electrochemical process. Finally, small amounts of carboxylic acids were detected, including dichloroacetic acid, especially when using a BDD electrode.


Assuntos
Técnicas Eletroquímicas/métodos , Glicina/análogos & derivados , Água Subterrânea/química , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/química , Purificação da Água/métodos , Ácidos Carboxílicos/análise , Diamante/química , Eletrodos , Glicina/análise , Oxidantes/química , Oxirredução , Raios Ultravioleta
4.
F1000Res ; 82019.
Artigo em Inglês | MEDLINE | ID: mdl-31583082

RESUMO

Hypochlorous acid (HOCl; bleach) is a powerful weapon used by our immune system to eliminate invading bacteria. Yet the way HOCl actually kills bacteria and how they defend themselves from its oxidative action have only started to be uncovered. As this molecule induces both protein oxidation and aggregation, bacteria need concerted efforts of chaperones and antioxidants to maintain proteostasis during stress. Recent advances in the field identified several stress-activated chaperones, like Hsp33, RidA, and CnoX, which display unique structural features and play a central role in protecting the bacterial proteome during HOCl stress.


Assuntos
Bactérias/metabolismo , Ácido Hipocloroso/química , Chaperonas Moleculares/metabolismo , Oxidantes/química , Estresse Fisiológico , Infecções Bacterianas/imunologia , Proteínas de Bactérias/metabolismo , Humanos , Oxirredução , Proteólise
5.
J Photochem Photobiol B ; 200: 111647, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31648133

RESUMO

Photoactive materials called photosensitizers can be used for treatment of different types of cancer in combination with light source. In this paper, we have investigated pro-oxidant and antioxidant potentials of four graphene based nanomaterials (graphene oxide-GO, graphene quantum dots-GQDs, carbon quantum dots-CQDs and N-doped carbon quantum dots-N-CQDs) depending on the presence/absence of visible light source. Structural and optical properties of these materials and their potentials for reactive oxygen species generation/quenching are investigated by applying different microscopy and spectroscopy techniques (transmission electron microscopy, FTIR, UV-Vis, photoluminescence, electron paramagnetic resonance). Results show that all types of quantum dots has pro-oxidant and antioxidant potentials whereas GO demonstrated only moderate antioxidant effect. The best free radical scavenger is CQDs sample in the absence of light. CQDs are the best singlet oxygen generator under blue light irradiation as well. To check photo-cytotoxicity of these materials, photo-cytotoxic concentrations of the GO, GQDs, CQDs and N-CQDs were determined for three cellular lines: human rhabdomyosarcoma (RD), cell line derived from human cervix carcinoma Hep2c (HeLa) and fibroblast cell line from murine (L2OB). Cytotoxicity test has indicated that all samples are much less photocytotoxic than cis-diamminedichloroplatinum (cis-DPP). The production method and doping of quantum dots affect the photodynamic activity of tested samples very much.


Assuntos
Antioxidantes/química , Grafite/química , Oxidantes/química , Carbono/química , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Grafite/toxicidade , Humanos , Microscopia Confocal , Pontos Quânticos/química , Pontos Quânticos/toxicidade , Oxigênio Singlete/química , Oxigênio Singlete/metabolismo
6.
Chemosphere ; 235: 1007-1014, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31561289

RESUMO

Electro-peroxone is a novel advanced oxidation process that surpasses ozonation or peroxone because of its advantages. In this technology, combining ozone and hydrogen peroxide generated electrochemically leads to the production of hydroxyl radicals, which are the strongest oxidizing agents. In this study, a cylindrical reactor with a continuous circular flow using novel arrangements of electrodes was used to examine the effects of variant parameters on dye removal efficiency. Acid Orange 7 (C16H11N2NaO4S) served as an indicator pollutant. Based on overall energy consumption and energy consumption per dye removed weight, electro-peroxone not only has proper efficiency at high dye concentrations, it also has the least energy consumption per dye removed weight; 53 KWh kg-1 is achieved for 500 mg L-1 initial dye concentration at 99% removal efficiency after 40 min. The results show that at the optimum condition of [Dye] = 500 mg L-1, pH = 7.7, applied current = 0.5 A, O3 rate = 1 L min-1, and [Na2SO4] = 0.1 M, dye is removed completely after 90 min and COD and TOC removal is 99% and 90%, respectively. LC-MS results also showed that AO7 initially was converted to more toxic compounds than AO7 like benzoic acid but finally linear acidic intermediate with less toxicity such as fumaric acid was formed.


Assuntos
Compostos Azo/química , Benzenossulfonatos/química , Eletrodos , Peróxido de Hidrogênio/química , Radical Hidroxila/química , Oxidantes/química , Ozônio/química , Poluentes Químicos da Água/química , Compostos Azo/análise , Benzenossulfonatos/análise , Eletrólise , Oxirredução , Poluentes Químicos da Água/análise
7.
Molecules ; 24(17)2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31480640

RESUMO

Catalysis mediated by iron complexes is emerging as an eco-friendly and inexpensive option in comparison to traditional metal catalysis. The epoxidation of alkenes constitutes an attractive application of iron(III) catalysis, in which terminal olefins are challenging substrates. Herein, we describe our study on the design of biomimetic non-heme ligands for the in situ generation of iron(III) complexes and their evaluation as potential catalysts in epoxidation of terminal olefins. Since it is well-known that active sites of oxidases might involve imidazole fragment of histidine, various simple imidazole derivatives (seven compounds) were initially evaluated in order to find the best reaction conditions and to develop, subsequently, more elaborated amino acid-derived peptide-like chiral ligands (10 derivatives) for enantioselective epoxidations.


Assuntos
Alcenos/química , Materiais Biomiméticos/química , Compostos de Epóxi/química , Heme/química , Peróxido de Hidrogênio/química , Ferro/química , Oxidantes/química , Catálise , Domínio Catalítico , Imidazóis/química , Ligantes , Conformação Molecular , Peptídeos/química
8.
Artigo em Inglês | MEDLINE | ID: mdl-31484407

RESUMO

The wastewater produced from the oilfield is chemically corrosive due to high salinity in combination with high temperatures. It is also rich in contaminants, such as oil, polyacrylamide, emulsions, suspended solid, etc. The density difference between the oil and water in the wastewater is low, which makes separation via gravity difficult. In this study, a combined pilot treatment is studied, which includes Fenton oxidation, settlement, activated carbon adsorption, and ultrafiltration (UF). The operational conditions of Fenton oxidation are optimized based on alleviating the fouling of the UF membrane. When the Fenton oxidation was operated at the molar ratio of H2O2 to FeSO4 3:1 and pH 2.2-2.5, the UF membrane could operate continuously for 20 h without cleaning. The membrane was fouled by the organics (oil/grease) and polymer, which can be effectively removed by composite cleaning reagent consisting of 0.1% NaOH and 0.1% sodium dodecylbenzenesulfonate (SDBS). With the UF treatment, the chemical oxygen demand (COD) of the effluent was less than 50 mg/L, which could meet the upgraded standard.


Assuntos
Resíduos Industriais , Campos de Petróleo e Gás , Eliminação de Resíduos Líquidos/métodos , Adsorção , Análise da Demanda Biológica de Oxigênio , Carvão Vegetal/química , Compostos Ferrosos/química , Peróxido de Hidrogênio/química , Membranas Artificiais , Oxidantes/química , Oxirredução , Ultrafiltração , Águas Residuárias
9.
Ecotoxicol Environ Saf ; 183: 109548, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31404726

RESUMO

Chemical oxidation has been applied to remove soil contaminants and thereby reduce human and ecological risks from contaminated sites. However, few studies have been conducted on the natural infiltration of oxidant solutions into unsaturated soil. Moreover, the infiltration capacity of oxidant solutions at various concentrations in unsaturated soil has not yet been studied. This study investigated the natural infiltration tendency of oxidant solutions like hydrogen peroxide (H2O2), potassium permanganate (KMnO4), and sodium persulfate (Na2S2O8), in sand and sandy loam. Cumulative infiltration was recorded from a soil column equipped with a Mariotte reservoir. The infiltration rate, sorptivity, and unsaturated hydraulic conductivity were obtained from the cumulative infiltration results. Na2S2O8 showed the highest infiltration rate in both sand and sandy loam, and the infiltration of Na2S2O8 increased as the concentration was increased from 0.05 to 1%. However, the infiltration of KMnO4 and H2O2 solutions was governed more by chemical reaction behavior than by liquid physical properties or soil hydraulic properties. The production of oxides and gas due to reaction induced clogging in flow paths, resulting in less infiltration. Infiltration of H2O2 at concentrations greater than 0.5% was not observed in sand or sandy loam due to gas formation and swelling.


Assuntos
Peróxido de Hidrogênio/química , Oxidantes/química , Permanganato de Potássio/química , Compostos de Sódio/química , Poluentes do Solo/análise , Solo/química , Sulfatos/química , Oxirredução , Óxidos/análise , Medição de Risco
10.
Chemosphere ; 234: 658-667, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31234083

RESUMO

Introducing peroxymonosulfate (PMS) and peroxydisulfate (PDS) into the photocatalytic fuel cell (PFC) system were investigated by comparing the Reactive Brilliant Blue (KN-R) degradation and synchronous electricity production. The two persulfates (PS) themselves are strong oxidant, and could be activated and as electron sacrificial agent in the PFCs, facilitating the photoelectrocatalysis and expanding redox to the entire cell space. Hence, the two established PFC/PS systems manifested prominent cell performances, enhancing the KN-R decomposition and electric power production relative to the virgin PFC. Thereinto, the KN-R removal rate of PFC/PMS was faster than that of PFC/PDS, but an opposite trend appeared in the electricity generation. Besides, the cell performances of the two cooperative systems were evaluated at different operation conditions, including PS dosage, solution pH, and irradiation strength. Moreover, the dye elimination principle was explored by radicals scavenging experiment, and the consequence revealed that hydroxyl radical (HO•), sulfate radical (SO4•-) and singlet oxygen were chief active species in the PFC/PMS, and HO•, SO4•- and superoxide anion played the key roles in the PFC/PDS. Furthermore, the calculated economic indicator demonstrated that the economy of the two synergistic processes were greater than that of UV/PS and solo PFC, and the PFC/PDS was more cost-effective than PFC/PMS.


Assuntos
Benzenossulfonatos/metabolismo , Fontes de Energia Elétrica , Eletricidade , Oxidantes/química , Peróxidos/química , Poluentes Químicos da Água/química , Catálise , Oxirredução , Processos Fotoquímicos
11.
Med Hypotheses ; 128: 69-75, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31203913

RESUMO

Vitiligo (VL) is a chronic autoimmune pigmentation disorder characterized by destruction of melanocytes. The condition is associated with several other autoimmune diseases, but autoimmune thyroid diseases, especially Hashimoto's thyroiditis (HT), is the most prevalent organ-specific autoimmune disease with a co-morbidity up to 34%. Among the many hypotheses that have been proposed for the pathogenesis of both diseases, autoimmunity and oxidative stress-mediated toxicity in melanocytes or thyrocytes, respectively, have been the most widely accepted - with autoimmunity being the presumed consequence of oxidative stress-mediated toxicity. However, the predominant etiologic basis for impairment of redox balance has rarely been studied. The two autoimmune diseases are not only linked by a concordance of clinical presentations and an autoimmune/oxidative stress-mediated toxicity pathogenesis but also by an apparent biochemical commonality. The target molecules produced in the thyroid and skin, i.e., thyroxine and melanin, respectively, are derived from the same primordial parent molecule, tyrosine. On the basis of these similarities between Hashimoto's thyroiditis and vitiligo, specifically with respect to the activation of oxidative stress, we propose a novel hypothesis accounting for the destruction of melanocytes or thyrocytes in VL and AT. We suggest a new therapeutic regimen of quinone derivatives to combat ROS-induced autoimmunity resulting from this common biochemical etiologic error.


Assuntos
Doenças Autoimunes/fisiopatologia , Doença de Hashimoto/fisiopatologia , Estresse Oxidativo , Vitiligo/fisiopatologia , Animais , Doenças Autoimunes/complicações , Autoimunidade , Benzoquinonas/química , Modelos Animais de Doenças , Doença de Hashimoto/complicações , Humanos , Peróxido de Hidrogênio/química , Hidroquinonas/química , Melaninas/química , Melanócitos/citologia , Melanócitos/metabolismo , Modelos Teóricos , Oxidantes/química , Oxirredução , Oxigênio/química , Espécies Reativas de Oxigênio/metabolismo , Superóxidos/química , Células Epiteliais da Tireoide/metabolismo , Glândula Tireoide/metabolismo , Tiroxina , Vitiligo/complicações
12.
Molecules ; 24(12)2019 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-31226759

RESUMO

Sorbus domestica leaves are a traditionally used herbal medicine recommended for the treatment of oxidative stress-related diseases. Dry leaf extracts (standardized by LC-MS/MS and LC-PDA) and nine model activity markers (polyphenols), were tested in scavenging assays towards six in vivo-relevant oxidants (O2•-, OH•, NO•, H2O2, ONOO-, HClO). Ascorbic acid (AA) and Trolox (TX) were used as positive standards. The most active extracts were the diethyl ether and ethyl acetate fractions with activities in the range of 3.61-20.03 µmol AA equivalents/mg, depending on the assay. Among the model compounds, flavonoids were especially effective in OH• scavenging, while flavan-3-ols were superior in O2•- quenching. The most active constituents were quercetin, (-)-epicatechin, procyanidins B2 and C1 (3.94-24.16 µmol AA/mg), but considering their content in the extracts, isoquercitrin, (-)-epicatechin and chlorogenic acid were indicated as having the greatest influence on extract activity. The analysis of the synergistic effects between those three compounds in an O2•- scavenging assay demonstrated that the combination of chlorogenic acid and isoquercitrin exerts the greatest influence. The results indicate that the extracts possess a strong and broad spectrum of antioxidant capacity and that their complex composition plays a key role, with various constituents acting complementarily and synergistically.


Assuntos
Antioxidantes/química , Oxidantes/química , Plantas Medicinais/química , Sorbus/química , Antioxidantes/farmacologia , Flavonoides/química , Flavonoides/farmacologia , Humanos , Peróxido de Hidrogênio/química , Oxidantes/farmacologia , Oxirredução/efeitos dos fármacos , Fenóis/química , Fitoterapia , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Espectrometria de Massas em Tandem
13.
Ultrason Sonochem ; 55: 117-124, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31084785

RESUMO

The aim of the present investigation was the combination of ZnO nanostructures with nano-cellulose (NC) for the efficient degradation of tetracycline (TC) antibiotic under ultrasonic irradiation. The removal efficiency of 12.8% was obtained by the sole use of ultrasound (US), while the removal efficiency increased up to 70% by the US/ZnO treatment process. Due to the integration of ZnO nanostructures with NC, the removal efficiency of 87.6% was obtained within 45 min. The removal efficiency substantially decreased in the presence of tert-butyl alcohol (more than 25% reduction), indicating that radOH-mediation oxidation is responsible for the degradation of TC molecules. Peroxymonosulfate (PMS) led to the most enhancing effect on the removal of TC among percarbonate, persulfate and periodate ions. The addition of PMS caused the degradation efficiency of 96.4% within the short contact time of 15 min. The bio-toxicity examination on the basis of inhibition test conducted on activated sludge revealed diminishing the oxygen consumption inhibition percent [IOUR (%)] from 33.6 to 22.1% during the US/ZnO/NC process. Consequently, the utilization of the US/ZnO/NC process can convert TC molecules to less toxic compounds. However, longer reaction time is required for complete conversion into non-toxic substances.


Assuntos
Celulose/química , Nanocompostos/química , Tetraciclina/química , Tetraciclina/isolamento & purificação , Ondas Ultrassônicas , Óxido de Zinco/química , Antibacterianos/química , Antibacterianos/isolamento & purificação , Catálise , Oxidantes/química , Peróxidos/química , Água/química , Poluentes Químicos da Água/química , Poluentes Químicos da Água/isolamento & purificação
14.
Biochimie ; 162: 185-197, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31059754

RESUMO

Flavonoids like quercetin and myricetin serve as naturally occurring antioxidants but their bioactivity is limited due to low aqueous solubility and oxidation under physiological conditions. In this current study, the antioxidant activity of quercetin and myricetin loaded chitosan nanoparticles during the induced oxidation of Ribonuclease A (RNase A) has been compared with the corresponding free flavonoids. Oxidation of RNase A leads to intermolecular dityrosine (DT) bond formation which shows a characteristic fluorescence emission around 405 nm. Although both quercetin and myricetin loaded nanoparticles initially exhibit lower antioxidant property compared to the free flavonoids, however, with increase in oxidant concentration over time the DT fluorescence showed greater increase for free flavonoids in comparison to the nanoparticles. The polyphenol loaded nanoparticles are also found to be effective in preventing bacterial cell damage in oxidizing medium. The slow release of flavonoids from the nanoparticles is responsible for their prolonged antioxidant effect in the oxidizing medium unlike the free flavonoids which are exhausted almost completely in the initial phase.


Assuntos
Flavonoides/farmacologia , Nanopartículas/química , Estresse Oxidativo/efeitos dos fármacos , Quercetina/farmacologia , Ribonuclease Pancreático/metabolismo , Antioxidantes/farmacologia , Quitosana/química , Escherichia coli , Simulação de Acoplamento Molecular/métodos , Oxidantes/química , Oxirredução , Polifenóis/farmacologia , Tirosina/análogos & derivados , Tirosina/metabolismo
15.
Chemosphere ; 228: 335-344, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31039540

RESUMO

Existing methods for cleanup of wastewaters and soils polluted with the extremely toxic rocket fuel unsymmetrical dimethylhydrazine (UDMH) are mainly based on the treatment with various oxidative reagents. Until now, the assessment of their effectiveness was based on the residual content of UDMH and did not take into account the possibility of the formation of a large number of potentially dangerous nitrogen-containing transformation products (TPs). In this study, using the recently developed approach based on high-resolution Orbitrap mass spectrometry, the comprehensive characterization of UDMH TPs formed by the action of air oxygen and different oxidants (Fenton's reagent, KMnO4, HOCl, H2O2 in the presence of Cu2+ and [Fe (EDTA)]- catalysts) typically used to detoxify spill sites was performed. The range of the identified molecular formulas of TPs comprised 303 compounds of various classes. Among them, there is a number of major products not previously described in the literature. It was established that none of the investigated oxidative reagents ensures complete conversion of rocket fuel to safe compounds. The hydrogen peroxide based reagents, particularly H2O2 + Na [Fe (EDTA)] system currently used in Kazakhstan, give the greatest number of TPs, for many of which a toxicity was not characterized so far. The majority of the compounds found in model solutions was detected in extracts of soil from the crash site of the Proton carrier rocket, which was subjected to the on-site reagent treatment. During successive treatments, along with the decrease in the number of detectable UDMH TPs, their ratios change in favor of amines.


Assuntos
Dimetilidrazinas/química , Espectrometria de Massas/métodos , Oxidantes/química , Solo/química , Água/química , Dimetilidrazinas/análise
16.
Environ Sci Pollut Res Int ; 26(19): 19684-19696, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31081534

RESUMO

Doxorubicin (DOX) is a chemotherapeutic agent from anthracycline class, which acts unselectively on all cells; thus, it may have genotoxic and/or mutagenic effects and cause serious environmental problems. Herein, the decomposition of a diluted solution of DOX hydrochloride for injection has been investigated under photo-oxidative conditions, in ambient light and without pH modification, using hydrogen peroxide as oxidizing agent and hydrophobic siloxane-based metal-organic frameworks (MOFs) as heterogeneous catalysts. The kinetics of the photodegradation process was followed by UV-Vis spectroscopy and by ESI-MS. According to UV-Vis data, two pseudo-first-order kinetic steps describe the process, with rate constants in the order of 10-3-10-2 min-1 for the rate-determining one. ESI-MS provided more accurate information, with a rate constant of 2.6 · 10-2 min-1 calculated from the variation of DOX ion abundance. Complete decomposition of DOX was achieved after 120 min in the shade and after only 20 min by exposure to sunlight. The analysis of the residual waters by mass spectrometry and 1D and 2D NMR spectroscopy showed complete disappearance of DOX in all cases, excluded any anthracycline species, which are destroyed in the tested conditions, and proved formation of an un-harmful compound-glycerol, while no trace of metal was detected by XRF. Preliminary data also showed decomposition of oxytetracycline in similar conditions. By this study, we bring into attention a less-addressed pollution issue and we propose a mild and effective method for the removal of drug emerging pollutants.


Assuntos
Doxorrubicina/análise , Luz , Estruturas Metalorgânicas/química , Fotólise , Siloxanas/química , Poluentes Químicos da Água/análise , Purificação da Água/métodos , Catálise , Doxorrubicina/efeitos da radiação , Peróxido de Hidrogênio/química , Concentração de Íons de Hidrogênio , Cinética , Oxidantes/química , Oxirredução , Poluentes Químicos da Água/efeitos da radiação
17.
Int J Biol Macromol ; 134: 1-10, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31071390

RESUMO

In this work, various new nano-alkalinecellulose carboxylates (NACCs) were prepared by oxidative hydrolysis of microalkalinecellulose (MACp) given from prewashed cotton. After the optimization of the reaction time, temperature, oxidant system, and oxidant loading, the new flake-shape anionic NACC24 with base capacity 10.8 mmol HO-/g was obtained from MACp at 50 °C. The characterized NACC24 and MACp were comparatively used as bio-sorbent for removal of methylene blue (MB) from wastewater and as the catalyst in the large-scale synthesis of nifedipine. With the Langmuir model and monolayer pseudo-second-order kinetic mechanism, the negatively charged polymer NACC24 represented high sorption capacity for the MB removal at 780 ±â€¯10 mg/g. A high regeneration stability and 90.5% original efficiency was verified for the NACC24 after five consequence adsorption-desorption cycles, where acidic methanol and aqueous NaOH were used for the efficient desorption of electrostatically interacted MB to NACC24 and respective reactivation of the NACC24 for further runs. Besides, NACC24 showed a high catalytic activity in the base-catalyzed rapid synthesis of anti-hypertension nifedipine even after the five times reusing of catalyst.


Assuntos
Celulose/análogos & derivados , Celulose/química , Azul de Metileno , Nanopartículas/química , Nifedipino/síntese química , Adsorção , Catálise , Técnicas de Química Sintética , Cinética , Azul de Metileno/química , Estrutura Molecular , Nanopartículas/ultraestrutura , Oxidantes/química , Espectroscopia de Infravermelho com Transformada de Fourier , Águas Residuárias/química , Poluentes Químicos da Água , Purificação da Água
18.
Adv Exp Med Biol ; 1127: 59-65, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31140171

RESUMO

Inhibition of xanthine oxidoreductase (XOR) has proven beneficial in a plethora of inflammatory disease processes due to a net reduction in pro-inflammatory oxidants and secondary nitrating species. Electrophilic nitrated fatty acid derivatives, such as nitro-oleic acid (OA-NO2) are also noted to display a broad spectrum of anti-inflammatory effects via interaction with critical signaling pathways. An alternative process in which nitrated fatty acids may extend anti-inflammatory actions is via inactivation of XOR, a process that is more effective than allo/oxypurinol-mediated inhibition. Herein, we describe the molecular aspects of nitrated fatty acid-associated inactivation of XOR, identify specificity via structure function relationships and discuss XOR as a crucial component of the anti-inflammatory portfolio of nitrated fatty acids.


Assuntos
Ácidos Graxos/farmacologia , Inflamação , Nitratos/química , Oxidantes/química , Xantina Desidrogenase/antagonistas & inibidores , Humanos
19.
Pharm Res ; 36(7): 103, 2019 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-31101998

RESUMO

PURPOSE: A rapid and broadly applicable method to assess relevant oxidative damage in biopharmaceuticals is important for lifecycle management of product quality. Multiple methods are currently employed as stress tests to induce oxidative damage for assessment of stability, safety, and efficacy. We compared two common methods for inducing oxidative damage to assess differences in impact on bioactivity and structure of the biopharmaceuticals. METHODS: Biopharmaceuticals were treated with either metal-catalyzed oxidation (MCO) conditions or the reactive-oxygen species (ROS) inducer 2,2'-Azobis(2-amidinopropane) dihydrochloride (AAPH), then analyzed for changes in structure and bioactivity. RESULTS: We demonstrate that commonly used chemical methods for assessing oxidation yield distinct oxidation profiles for each of the biotechnology products analyzed, including monoclonal antibodies. We further report oxidant- and product-specific changes in bioactivity under oxidizing conditions, along with differential oxidation on the molecular subunits of monoclonal antibodies. CONCLUSION: Our results highlight the need for product-specific optimization and selection of orthogonal, relevant oxidizers when characterizing stress responses in biopharmaceuticals.


Assuntos
Produtos Biológicos/química , Estresse Oxidativo , Anticorpos Monoclonais Humanizados/química , Anticorpos Monoclonais Humanizados/farmacologia , Antineoplásicos Imunológicos/química , Antineoplásicos Imunológicos/farmacologia , Produtos Biológicos/farmacologia , Linhagem Celular Tumoral , Estabilidade de Medicamentos , Humanos , Indicadores e Reagentes/química , Metionina/química , Oxidantes/química , Oxirredução , Espécies Reativas de Oxigênio/química , Rituximab/química , Rituximab/farmacologia , Trastuzumab/química , Trastuzumab/farmacologia
20.
Int J Mol Sci ; 20(8)2019 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-30991685

RESUMO

Fracturing wastewater is often highly emulsified, viscous, and has a high chemical oxygen demand (COD), which makes it difficult to treat and recycle. Ferrate(VI) is a green oxidant that has a high redox potential and has been adopted for the efficient oxidation of fracturing wastewater to achieve triple effects: demulsification, visbreaking, and COD removal. Firstly, optimal conditions were identified to build a model for fast and efficient treatment. Secondly, wastewater treatment using ferrate oxidation was investigated via demulsification, visbreaking, and COD removal. Finally, a mechanism for ferrate oxidation was proposed for the three effects using Fourier-transform infrared (FT-IR) spectroscopy and scanning electron microscopy (SEM). The theoretical and experimental data demonstrated that the ferrate oxidation achieved the three desired effects. When ferrate was added, the demulsification efficiency increased from 56.2% to 91.8%, the total viscosity dropped from 1.45 cp to 1.10 cp, and the total removal rate of COD significantly increased to 74.2%. A mechanistic analysis showed that the strongly-oxidizing ferrate easily and efficiently oxidized the O/W interfacial film materials, viscous polymers, and compounds responsible for the COD, which was a promising result for the triple effects.


Assuntos
Emulsões/química , Compostos de Ferro/química , Oxidantes/química , Compostos de Potássio/química , Águas Residuárias/química , Análise da Demanda Biológica de Oxigênio , Oxirredução , Viscosidade , Poluentes Químicos da Água , Purificação da Água/métodos
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