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2.
Chemosphere ; 341: 140097, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37683949

RESUMO

The retention capacity of natural calcareous gravels used as a filling material between the packages containing radioactive waste materials in the disposal cells was evaluated for Sr, U, Ni, Ag, 14C, 99Tc, 239Pu, 228Th and 152Eu. The thermodynamic calculations performed considering repository conditions indicated that the chemistry of most of these elements was dominated by neutral or cationic species, this is the case of 238Pu 152Eu, 228Th, Ni and Ag. The studied gravels presented high sorption capacities for these cationic or neutral species, but they are not efficient on retaining anionic species as in the case of 99Tc or Sr, which is already present in the composition of the studied gravels. For those elements where the predominant species are carbonated (14C and U) low distribution coefficients were obtained. A preliminary mechanistic sorption model was developed for each radionuclide considering carbonate (>CO3H) and calcium hydroxide (>CaOH) sites. Our preliminary model allowed to successfully reproduce the experimental trend of the data obtained in this work.


Assuntos
Hidróxido de Cálcio , Resíduos Radioativos , Radioisótopos , Termodinâmica
3.
Vet Parasitol ; 320: 109981, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37450963

RESUMO

Fasciolosis is a globally widespread trematodiasis with a major economic and veterinary impact. Therefore, this disease is responsible for millions of dollars in losses to the livestock industry, and also constitutes an emerging human health problem in endemic areas. The ubiquitous nature of Fasciola hepatica, the main causative agent, is one of the key factors for the success of fasciolosis. Accordingly, this parasite is able to subsist in a wide variety of ecosystems and hosts, thanks to the development of a plethora of strategies for adaption and immune evasion. Fasciolosis comprises a growing concern due to its high prevalence rates, together with the emergence of strains of the parasite resistant to the treatment of choice (triclabendazole). These facts highlight the importance of developing novel control measures which allow for an effective protection against the disease before F. hepatica settles in a niche inaccessible to the immune system. However, knowledge about the initial phases of the infection, including the migration mechanisms of the parasite and the early innate host response, is still scarce. Recently, our group developed an in vitro host-parasite interaction model that allowed the early events to be unveiled after the first contact between the both actors. This occurs shortly upon ingestion of F. hepatica metacercariae and the emergence of the newly excysted juveniles (FhNEJ) in the host duodenum. Here, we present a transcriptomic analysis of such model using an approach based on RNA sequencing (RNA-Seq), which reveals changes in gene expression related to proteolysis and uptake of metabolites in FhNEJ. Additionally, contact with the parasite triggered changes in host intestinal cells related to pseudogenes expression and host defence mechanisms, including immune response, among others. In sum, these results provide a better understanding of the early stages of fasciolosis at molecular level, and a pool of targets that could be used in future therapeutic strategies against the disease.


Assuntos
Fasciola hepatica , Fasciolíase , Humanos , Animais , Fasciola hepatica/fisiologia , Transcriptoma , Ecossistema , Fasciolíase/veterinária , Células Epiteliais
4.
Int J Mol Sci ; 24(9)2023 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-37175870

RESUMO

Fasciola hepatica is the main causative agent of fasciolosis, a zoonotic parasitic disease of growing public health concern. F. hepatica metacercariae are ingested by the host and excyst in the intestine, thereby releasing the newly excysted juveniles (FhNEJ), which traverse the gut wall and migrate towards the biliary ducts. Since blocking F. hepatica development is challenging after crossing of the intestinal wall, targeting this first step of migration might result in increased therapeutic success. The intestinal extracellular matrix (ECM) is constituted by a network of structural proteins, including laminin (LM) and fibronectin (FN), that provide mechanical support while acting as physical barrier against intestinal pathogens. Here, we employed ELISA and immunofluorescent assays to test for the presence of LM- and FN-binding proteins on a tegument-enriched antigenic fraction of FhNEJ, and further determined their identity by two-dimensional electrophoresis coupled to mass spectrometry. Additionally, we performed enzymatic assays that revealed for the first time the capability of the juvenile-specific cathepsin L3 to degrade LM, and that LM degradation by FhNEJ proteins is further potentiated in the presence of host plasminogen. Finally, a proteomic analysis showed that the interaction with LM triggers protein changes in FhNEJ that may be relevant for parasite growth and adaptation inside the mammalian host. Altogether, our study provides valuable insights into the molecular interplay between FhNEJ and the intestinal ECM, which may lead to the identification of targetable candidates for the development of more effective control strategies against fasciolosis.


Assuntos
Fasciola hepatica , Fasciolíase , Animais , Fasciola hepatica/metabolismo , Laminina/metabolismo , Proteômica , Intestinos , Espectrometria de Massas , Fasciolíase/parasitologia , Mamíferos
5.
PLoS Negl Trop Dis ; 16(10): e0010811, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-36223411

RESUMO

Fasciolosis caused by the trematode Fasciola hepatica is a zoonotic neglected disease affecting animals and humans worldwide. Infection occurs upon ingestion of aquatic plants or water contaminated with metacercariae. These release the newly excysted juveniles (FhNEJ) in the host duodenum, where they establish contact with the epithelium and cross the intestinal barrier to reach the peritoneum within 2-3 h after infection. Juveniles crawl up the peritoneum towards the liver, and migrate through the hepatic tissue before reaching their definitive location inside the major biliary ducts, where they mature into adult worms. Fasciolosis is treated with triclabendazole, although resistant isolates of the parasite are increasingly being reported. This, together with the limited efficacy of the assayed vaccines against this infection, poses fasciolosis as a veterinary and human health problem of growing concern. In this context, the study of early host-parasite interactions is of paramount importance for the definition of new targets for the treatment and prevention of fasciolosis. Here, we develop a new in vitro model that replicates the first interaction between FhNEJ and mouse primary small intestinal epithelial cells (MPSIEC). FhNEJ and MPSIEC were co-incubated for 3 h and protein extracts (tegument and soma of FhNEJ and membrane and cytosol of MPSIEC) were subjected to quantitative SWATH-MS proteomics and compared to respective controls (MPSIEC and FhNEJ left alone for 3h in culture medium) to evaluate protein expression changes in both the parasite and the host. Results show that the interaction between FhNEJ and MPSIEC triggers a rapid protein expression change of FhNEJ in response to the host epithelial barrier, including cathepsins L3 and L4 and several immunoregulatory proteins. Regarding MPSIEC, stimulation with FhNEJ results in alterations in the protein profile related to immunomodulation and cell-cell interactions, together with a drastic reduction in the expression of proteins linked with ribosome function. The molecules identified in this model of early host-parasite interactions could help define new tools against fasciolosis.


Assuntos
Fasciola hepatica , Fasciolíase , Proteômica , Animais , Catepsinas , Fasciolíase/parasitologia , Camundongos , Triclabendazol , Vacinas
6.
PLoS Negl Trop Dis ; 16(9): e0010766, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-36112664

RESUMO

Fasciola hepatica is a trematode parasite that infects animals and humans causing fasciolosis, a worldwide-distributed disease responsible for important economic losses and health problems. This disease is of growing public health concern since parasite isolates resistant to the current treatment (triclabendazole) have increasingly been described. F. hepatica infects its vertebrate host after ingestion of the encysted parasite (metacercariae), which are found in the water or attached to plants. Upon ingestion, newly excysted juveniles of F. hepatica (FhNEJ) emerge in the intestinal lumen and cross the intestinal barrier, reach the peritoneum and migrate to the biliary ducts, where adult worms fully develop. Despite the efforts made to develop new therapeutic and preventive tools, to date, protection against F. hepatica obtained in different animal models is far from optimal. Early events of host-FhNEJ interactions are of paramount importance for the infection progress in fasciolosis, especially those occurring at the host-parasite interface. Nevertheless, studies of FhNEJ responses to the changing host environment encountered during migration across host tissues are still scarce. Here, we set-up an ex vivo model coupled with quantitative SWATH-MS proteomics to study early host-parasite interaction events in fasciolosis. After comparing tegument and somatic fractions from control parasites and FhNEJ that managed to cross a mouse intestinal section ex vivo, a set of parasite proteins whose expression was statistically different were found. These included upregulation of cathepsins L3 and L4, proteolytic inhibitor Fh serpin 2, and a number of molecules linked with nutrient uptake and metabolism, including histone H4, H2A and H2B, low density lipoprotein receptor, tetraspanin, fatty acid binding protein a and glutathione-S-transferase. Downregulated proteins in FhNEJ after gut passage were more numerous than the upregulated ones, and included the heath shock proteins HSP90 and alpha crystallin, amongst others. This study brings new insights into early host-parasite interactions in fasciolosis and sheds light on the proteomic changes in FhNEJ triggered upon excystment and intestinal wall crossing, which could serve to define new targets for the prevention and treatment of this widespread parasitic disease.


Assuntos
Fasciola hepatica , Fasciolíase , alfa-Cristalinas , Animais , Catepsinas , Fasciola hepatica/metabolismo , Fasciolíase/parasitologia , Proteínas de Ligação a Ácido Graxo , Glutationa/metabolismo , Proteínas de Helminto/metabolismo , Histonas/metabolismo , Humanos , Camundongos , Proteômica , Receptores de LDL/metabolismo , Transferases/metabolismo , Triclabendazol , alfa-Cristalinas/metabolismo
9.
Front Pharmacol ; 13: 850583, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35496309

RESUMO

At the beginning of the pandemic, we observed that lithium carbonate had a positive effect on the recovery of severely ill patients with COVID-19. Lithium is able to inhibit the replication of several types of viruses, some of which are similar to the SARS-CoV-2 virus, increase the immune response and reduce inflammation by preventing or reducing the cytokine storm. Previously, we published an article with data from six patients with severe COVID-19 infection, where we proposed that lithium carbonate could be used as a potential treatment for COVID-19. Now, we set out to conduct a randomized clinical trial number EudraCT 2020-002008-37 to evaluate the efficacy and safety of lithium treatment in patients infected with severe SARS-CoV-2. We showed that lithium was able to reduce the number of days of hospital and intensive care unit admission as well as the risk of death, reduces inflammatory cytokine levels by preventing cytokine storms, and also reduced the long COVID syndromes. We propose that lithium carbonate can be used to reduce the severity of COVID-19.

10.
Cell Mol Neurobiol ; 42(6): 1921-1932, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-33712885

RESUMO

The brain extracellular matrix (ECM) is involved in crucial processes of neural support, neuronal and synaptic plasticity, extrasynaptic transmission, and neurotransmission. ECM is a tridimensional fibrillary meshwork composed of macromolecules that determine its bioactivity and give it unique characteristics. The characterization of the brain ECM is critical to understand its dynamic in SZ. Thus, a comparative study was developed with 71 patients with schizophrenia (SZ) and 70 healthy controls. Plasma of participants was analysed by label-free liquid chromatography-tandem mass spectrometry, and the results were validated using the classical western blot method. Lastly, immunostaining of post-mortem human brain tissue was performed to analyse the distribution of the brain ECM proteins by confocal microscopy. The analysis identified four proteins: fibronectin, lumican, nidogen-1, and secreted protein acidic and rich in cysteine (SPARC) as components of the brain ECM. Statistical significance was found for fibronectin (P = 0.0166), SPARC (P = 0.0003), lumican (P = 0.0012), and nidogen-1 (P < 0.0001) that were decreased in the SZ group. Fluorescence imaging of prefrontal cortex (PFC) sections revealed a lower expression of ECM proteins in SZ. Our study proposes a pathophysiological dysregulation of proteins of the brain ECM, whose abnormal composition leads to a progressive neuronal impairment and consequently to neurodegenerative processes due to lack of neurophysiological support and dysregulation of neuronal homeostasis. Moreover, the brain ECM and its components are potential pharmacological targets to develop new therapeutic approaches to treat SZ.


Assuntos
Fibronectinas , Esquizofrenia , Encéfalo/metabolismo , Matriz Extracelular/metabolismo , Proteínas da Matriz Extracelular/metabolismo , Fibronectinas/metabolismo , Humanos , Lumicana/metabolismo , Osteonectina/metabolismo , Esquizofrenia/tratamento farmacológico , Esquizofrenia/metabolismo
11.
Rev. psiquiatr. salud ment. (Barc., Ed. impr.) ; 14(3): 125-138, jul.-sept. 2021. tab, graf
Artigo em Espanhol | IBECS | ID: ibc-229563

RESUMO

Introducción: La esquizofrenia es una enfermedad crónica que suele ir acompañada de trastornos metabólicos como la diabetes, la obesidad y problemas cardiovasculares asociados muchas veces a estilos de vida poco saludables, así como a problemas neuroendocrinos ocasionados por la propia enfermedad. Los cambios en el estilo de vida, como la práctica de ejercicio físico regular, tienen un efecto positivo sobre los trastornos metabólicos y la salud mental. Sin embargo, se desconocen los cambios moleculares y su consecuente repercusión en los pacientes diagnosticados con esquizofrenia. Con este estudio se pretenden analizar los cambios moleculares inducidos por el ejercicio físico en pacientes crónicos con esquizofrenia.MétodosVeintiún pacientes con esquizofrenia crónica fueron sometidos a un programa de entrenamiento aeróbico diario durante 6 meses. El grupo de pacientes se dividió en 2 subgrupos: un subgrupo que completó en su totalidad el programa de entrenamiento (12 pacientes) y un segundo subgrupo que abandonó el programa el primer día (9 pacientes). Se analizaron los datos bioquímicos y clínicos de cada paciente y se estudió el perfil proteómico del plasma mediante ESI-LC-MS/MS de tipo shotgun.ResultadosEl análisis proteómico reconoció 21.165 proteínas y péptidos diferentes en el plasma de los pacientes. Concretamente, 4.657 proteínas sufrieron variaciones significativas, de las cuales fueron identificadas 1.812 proteínas relacionadas con las vías metabólicas y de regulación biológica. Tras el análisis de los parámetros clínicos en estos pacientes, se encontraron diferencias significativas en el peso, el IMC, el perímetro abdominal, la presión arterial diastólica y los niveles de colesterol HDL. La puntuación en la Escala de Autoevaluación de Anhedonia fue el cambio más significativo, siendo más elevada en el subgrupo que abandonó el programa de entrenamiento en comparación con el subgrupo activo. (AU)


Introduction: Schizophrenia is a chronic illness often accompanied by metabolic disorders, diabetes, obesity and cardiovascular problems often associated with unhealthy lifestyles, as well as neuroendocrine problems caused by the disease itself. Lifestyle changes, such as regular physical exercise, have a positive effect on metabolic disorders and mental health, although the molecular changes that occur in this type of patient and how they explain the changes in their response are unknown. This study wants to analyze in a novel way the proteins and molecular pathways involved in critical plasmatic proteins in plasma to reveal the pathways involved in the implementation of physical exercise and the changes that occur among patients who participate in such programs with those who leave.MethodsTwenty-one patients with chronic schizophrenia underwent a daily, 6-month aerobic training program. We divided them into a group that completed the program (12 patients) and a second group that left the training program (9 patients). The biochemical and clinical data of each patient were analyzed and the proteomic profile of the plasma was studied using ESI-LC-MS/MS.ResultsProteomic analysis recognizes 21.165 proteins and peptides in each patient, of which we identified 1,812 proteins that varied between both groups linked to the metabolic and biological regulation pathways. After clinical analysis of each patient we found significant differences in weight, BMI, abdominal perimeter, diastolic blood pressure, and HDL cholesterol levels. The main change that vertebrates both groups is the Self-Assessment Anhedonia Scale, where we detected higher levels in the dropout group (no physical activity) compared to the active group. (AU)


Assuntos
Humanos , Cromatografia Líquida , Exercício Físico , Proteômica , Espectrometria de Massas em Tandem , Esquizofrenia
12.
Int J Mol Sci ; 22(16)2021 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-34445205

RESUMO

The neurobiology of schizophrenia is multifactorial, comprising the dysregulation of several biochemical pathways and molecules. This research proposes a peripheral biomarker for schizophrenia that involves the second extracellular loop of norepinephrine transporter (NEText), the tropomyosin receptor kinase C (TrkC), and the neurotrophin-3 (NT-3) in T cells. The study of NEText, NT-3, and TrkC was performed in T cells and plasma extracted from peripheral blood of 54 patients with schizophrenia and 54 healthy controls. Levels of NT-3, TrkC, and NET were significantly lower in plasma and T cells of patients compared to healthy controls. Co-immunoprecipitation (co-IPs) showed protein interactions with Co-IP NEText-NT-3 and Co-IP NEText-TrkC. Computational modelling of protein-peptide docking by CABS-dock provided a medium-high accuracy model for NT-3-NEText (4.6935 Å) and TrkC-NEText (2.1365 Å). In summary, immunocomplexes reached statistical relevance in the T cells of the control group contrary to the results obtained with schizophrenia. The reduced expression of NT-3, TrkC, and NET, and the lack of molecular complexes in T cells of patients with schizophrenia may lead to a peripheral dysregulation of intracellular signaling pathways and an abnormal reuptake of norepinephrine (NE) by NET. This peripheral molecular biomarker underlying schizophrenia reinforces the role of neurotrophins, and noradrenergic and immune systems in the pathophysiology of schizophrenia.


Assuntos
Simulação de Acoplamento Molecular , Neurotrofina 3/química , Proteínas da Membrana Plasmática de Transporte de Norepinefrina/química , Receptor trkC/química , Esquizofrenia/etiologia , Adulto , Biomarcadores/metabolismo , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Neurotrofina 3/genética , Neurotrofina 3/metabolismo , Proteínas da Membrana Plasmática de Transporte de Norepinefrina/genética , Proteínas da Membrana Plasmática de Transporte de Norepinefrina/metabolismo , Estrutura Secundária de Proteína , Receptor trkC/genética , Receptor trkC/metabolismo , Esquizofrenia/genética , Esquizofrenia/metabolismo
13.
Rev Psiquiatr Salud Ment (Engl Ed) ; 14(3): 125-138, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34384726

RESUMO

INTRODUCTION: Schizophrenia is a chronic illness often accompanied by metabolic disorders, diabetes, obesity and cardiovascular problems often associated with unhealthy lifestyles, as well as neuroendocrine problems caused by the disease itself. Lifestyle changes, such as regular physical exercise, have a positive effect on metabolic disorders and mental health, although the molecular changes that occur in this type of patient and how they explain the changes in their response are unknown. This study wants to analyze in a novel way the proteins and molecular pathways involved in critical plasmatic proteins in plasma to reveal the pathways involved in the implementation of physical exercise and the changes that occur among patients who participate in such programs with those who leave. METHODS: Twenty-one patients with chronic schizophrenia underwent a daily, 6-month aerobic training program. We divided them into a group that completed the program (12 patients) and a second group that left the training program (9 patients). The biochemical and clinical data of each patient were analyzed and the proteomic profile of the plasma was studied using ESI-LC-MS/MS. RESULTS: Proteomic analysis recognizes 21.165 proteins and peptides in each patient, of which we identified 1.812 proteins that varied between both groups linked to the metabolic and biological regulation pathways. After clinical analysis of each patient we found significant differences in weight, BMI, abdominal perimeter, diastolic blood pressure, and HDL cholesterol levels. The main change that vertebrates both groups is the Self-Assessment Anhedonia Scale, where we detected higher levels in the dropout group (no physical activity) compared to the active group. CONCLUSION: The benefits of physical exercise are clear in chronic patients with schizophrenia, as it substantially improves their BMI, as well as their clinical and biochemical parameters. However, our study reveals the biological and molecular pathways that affect physical exercise in schizophrenia, such as important metabolic proteins such as ApoE and ApoC, proteins involved in neuronal regulation such as tenascin and neurotrophins, neuroinflammatory regulatory pathways such as lipocalin-2 and protein 14-3-3, as well as cytoskeleton proteins of cells such as spectrins and annexines. Understanding these molecular mechanisms opens the door to future therapies in the chronicity of schizophrenia.


Assuntos
Esquizofrenia , Animais , Cromatografia Líquida , Exercício Físico , Humanos , Projetos Piloto , Proteômica , Espectrometria de Massas em Tandem
14.
Nanomaterials (Basel) ; 11(7)2021 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-34202397

RESUMO

In this work, water extracts from different bio-based products of plant origin were studied to evaluate their antioxidant capacity and their potential to form metal nanoparticles from aqueous solutions. Two traditional tests, the Folin-Ciocalteu assay and the DPPH radical scavenging capacity method were compared with a more recent one, SNPAC, based on the formation of silver nanoparticles. The silver nanoparticle antioxidant capacity method (SNPAC) was optimized for its application in the characterization of the extracts selected in this work; kinetic studies and extract concentration were also evaluated. The extracts were obtained from leaves of oak, eucalyptus, green tea, white and common thyme, white cedar, mint, rosemary, bay, lemon, and the seaweed Sargassum muticum. The results demonstrate that any of these three methods can be used as a quick test to identify an extract to be employed for nanoparticle formation. Additionally, we studied the synthesis of Cu, Fe, Pb, Ni, and Ag nanoparticles using eucalyptus extracts demonstrating the efficiency of this plant extract to form metallic nanoparticles from aqueous metal salt solutions. Metal nanoparticles were characterized by transmission electron microscopy and dynamic light scattering techniques.

17.
Front Pharmacol ; 11: 557629, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32973537

RESUMO

Lithium has shown the capacity to: a) inhibit the replication of several types of viruses, some of which are similar to the SARS-CoV-2 virus, b) increase the immune response by reducing lymphopenia, and c) reduce inflammation by preventing or reducing the cytokine storm. In the present study, we have treated six patients with severe COVID-19 infection with lithium carbonate. We found that lithium carbonate significantly reduced plasma reactive C-Protein levels, increased lymphocyte numbers and decreased the neutrophil-lymphocyte ratio, improving both inflammatory activity and the immune response in these patients. We propose that lithium carbonate may deserve a place in the treatment against COVID-19.

18.
Sci Rep ; 10(1): 12168, 2020 Jul 22.
Artigo em Inglês | MEDLINE | ID: mdl-32699386

RESUMO

Most of the highly radioactive spent nuclear fuel (SNF) around the world is destined for final disposal in deep-mined geological repositories. At the end of the fuel's useful life in a reactor, about 96% of the SNF is still UO2. Thus, the behaviour of UO2 in SNF must be understood and evaluated under the weathering conditions of geologic disposal, which extend to periods of hundreds of thousands of years. There is ample evidence from nature that many uranium deposits have experienced conditions for which the formation of coffinite, USiO4, has been favoured over uraninite, UO2+x, during subsequent alteration events. Thus, coffinite is an important alteration product of the UO2 in SNF. Here, we present the first evidence of the formation of coffinite on the surface of UO2 at the time scale of laboratory experiments in a solution saturated with respect to amorphous silica at pH = 9, room temperature and under anoxic conditions.

19.
Food Chem ; 199: 597-604, 2016 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-26776013

RESUMO

In this work MALDI-TOF mass spectroscopy was investigated to characterise the ß-glucan profiles of several commercial health supplements, without any derivatisation or purification pre-treatment. The effect of two solvents (water and dimethyl sulfoxide) and two MALDI matrices (2,5-dihydroxybenzoic acid and 2',4',6'-trihydroxyacetophenone) was first evaluated on dextran standards. MALDI-TOF was found as a useful and quick technique to obtain structural information of diverse food supplements based on mushroom extracts. The MALDI polysaccharide profiles of 5 supplements from different mushroom species were qualitatively similar showing [Glucan+Na](+) cations with a peak-to-peak mass difference of 16 Da consistent with the repeating unit of the ß-(1→3)-glucan. The profiles strongly depended on the sample solvent used, with m/z values around 5000-8000 for water and 2000 for dimethyl sulfoxide; differences between samples were revealed in the molecular weight of the aqueous preparation, with the highest values for Maitake and Cordyceps species.


Assuntos
Agaricales/química , Polissacarídeos/análise , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Suplementos Nutricionais , Dimetil Sulfóxido , Peso Molecular , Solventes/química , Especificidade da Espécie , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos , Água , beta-Glucanas/análise , beta-Glucanas/química
20.
Bioresour Technol ; 139: 181-9, 2013 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-23665682

RESUMO

This work reports experimental evidences, not previously considered, to evaluate the Cr(VI) removal by protonated banana skin biomass. Variations in the number of hydroxyl groups, quantified by potentiometric titrations, and CO2 evolution during experiments, were attributed mainly to the oxidation of hydroxylic entities present in the studied material. The results indicate that these groups together with the carboxylic moieties are the main functionalities involved on the adsorption-coupled reduction process. The column experiment carried out provides a new approach to obtain the maximum reduction capacity of the material (3.72 mmol g(-1)). Moreover, we hereby propose a model that reports the first evidence for the instant bound of Cr(III) species to the material used, formed after the reduction of Cr(VI) present in solution. The removal process was quantified carrying out experiments under various pHs, biomass doses and Cr(VI) concentrations, and the mechanism underlying chromium removal was identified.


Assuntos
Cromo/química , Modelos Químicos , Musa/química , Prótons , Resíduos , Adsorção , Biomassa , Concentração de Íons de Hidrogênio , Cinética , Oxirredução , Potenciometria , Soluções , Temperatura , Fatores de Tempo
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