187 research outputs found

    Tailoring activated carbons as catalyst for catalytic wet air oxidation of phenol

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    Since the development of industrial activities in the whole world and specially nowadays, the access to clean water is more and more difficult. Over the past century our water consumption increased tenfold and, according to the World Health Organization, 1.1 thousand million people have no access to clean drinking water, while 2.4 thousand million lack proper sanitary provision. In addition, only 0.8 % of the world stock of water is actually fresh water, so that serious considerations on the availability of a constant supply of fresh water should be done. With this in mind, the need to have different techniques available to treat wastewater arises as a main concern, considering the great variety of chemical industries and activities than can produce contaminated effluents. Therefore, the detoxification of polluted water and its recycling when possible is mandatory for a sustainable and sustained development.For wastewater containing low to medium pollutant load, Catalytic Wet Air Oxidation (CWAO) yielded satisfactory results in laboratory studies, with the advantage that relatively mild operating conditions are needed, leading to lower investment and operation costs. Some activated carbons (AC) have been successfully used as catalyst in the CWAO of phenol in a trickle bed reactor (TBR) configuration. However, the reason for the catalytic activity of AC in CWAO is not yet completely understood. The objective of this work is to identify properties potentially responsible for the catalytic activity shown by some carbonaceous materials. With this goal, eight commercial activated carbons were tested as received and modified by several means (thermal treatment, acid wash and metal impregnation) and its catalytic performance evaluated in the oxidation of phenol. These modifications intended to highlight the effect of the surface oxygen functionalities, textural properties, i.e. surface area and pore volume, and iron (and other metals) content. Simultaneously, the activated carbons were physically and chemically characterised. The results confirm the hypothesis that mineral matter, specifically iron, is mainly responsible for the catalytic behaviour of activated carbons in the CWAO of phenol. However, having iron is not enough to be catalytically active in this reaction. It is necessary iron to be actually available in the carbonaceous matrix and in an appropriate state. Some final attempts for preparing tailored activated carbon from different raw sources still failed due to the lack of iron availability in the carbon matrix or the low mechanical stability of the material.The findings described in this PhD thesis open the doors for a better designing of tailored activated carbons from costless raw materials, allowing cheaper catalytic activated carbons to be available for wet oxidation of phenol. This fact should contribute to the wider implementation of CWAO for recovering polluted aqueous effluents that are reluctant to biotreatment.Debido al marcado desarrollo que han tenido las actividades industriales en el mundo, el acceso al agua potable es cada vez más difícil. Durante el último siglo el consumo mundial de agua se ha incrementado 10 veces y de acuerdo con información de la Organización Mundial de la Salud 1.1 miles de millones de personas no tienen acceso a agua potable y 2.4 miles de millones no disponen de las condiciones sanitarias apropiadas. Adicionalmente, sólo 0.8% de la reserva global de agua es apta para el consumo humano, por lo que serias medidas deben ser tomadas para garantizar un suministro constante de agua a la humanidad. Surge entonces como una necesidad, disponer de diferentes tecnologías de tratamientos de aguas residuales, especialmente considerando la gran variedad de industrias químicas existentes hoy en día, cuyos desechos son, en la mayoría de los casos, no sólo contaminantes sino también tóxicos para los seres vivos. Finalmente, es necesaria la purificación de los efluentes industriales para su posible reutilización si se pretende garantizar el desarrollo sustentable de la sociedad.La oxidación húmeda catalítica con aire (CWAO) es un tratamiento que ha demostrado ser eficiente para el tratamiento de aguas residuales con cargas orgánicas bajas o medias. Esta técnica posee la ventaja de ser eficiente incluso operando en condiciones moderadas de temperaturas y presión, lo que se refleja en bajos costos de instalación y mantenimiento. Si adicionalmente, el catalizador utilizado es de bajo coste, este tipo de tratamiento podría promoverse más fácilmente. Algunos carbones activos comerciales han sido empleados exitosamente como catalizadores en la CWAO de fenol en un reactor de lecho fijo de goteo. Sin embargo, las razones por las que este material presenta actividad catalítica no han sido completamente esclarecidas. Algunos estudios preliminares han demostrado que al realizar modificaciones en las propiedades de los carbones que presentan capacidad catalítica, generalmente se produce también una disminución en su capacidad para oxidar fenol.Por esto, el objetivo de este trabajo de investigación es identificar las propiedades potencialmente responsables de la actividad catalítica del carbón activo. Para ello, se utilizaron ocho carbones activos. Los mismos fueron modificados mediante diferentes tratamientos. Los carbones originales y todas las muestras resultantes de las modificaciones fueron utilizados como catalizadores en la oxidación del fenol, con el objetivo de evaluar el impacto de parámetros como las propiedades físicas (área superficial y porosidad), el contenido de grupos funcionales oxigenados y el contenido de hierro y otros metales en la actividad catalítica.Los resultados obtenidos en este trabajo demuestran que el contenido de hierro es un parámetro determinante que otorga capacidad catalítica al carbón activo. También se demostró que la disminución de grupos superficiales oxigenados mejora la capacidad de adsorción de fenol, obteniéndose mayor eliminación de este compuesto en efluentes líquidos. Finalmente, mediante técnicas de impregnación de metales, puede dotarse de actividad catalítica a materiales carbonosos que, por su origen, no la poseen pudiendo ser utilizados efectivamente en el tratamiento de aguas residuales

    Propuesta de un plan de capacitación comunitaria en turismo rural para la revalorización sociocultural del área de conservación privada Chaparrí, 2014

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    La presente investigación intitulada “Propuesta de un Plan de Capacitación Comunitaria en Turismo Rural para la Revalorización Sociocultural del Área de Conservación Privada Chaparrí”, se estructura definiendo las características técnicas de la estrategia integral que replanteará la revalorización sociocultural del Área de conservación Privada de Chaparrí en el distrito de Chongoyape, provincia de Chiclayo en el departamento de Lambayeque. Los resultados muestran que los ingresos salariales de algunos comuneros especialmente en mujeres y ancianos no son tan buenos debido a que ellos no participan en otras actividades laborales como suele suceder con otros sea el motivo por su condición de género y edad avanzada, los niños no participan en algunas actividades turísticas siendo de esta manera excluidos limitando su integración en la sociedad; tanto los comuneros como autoridades locales no contribuyen en gestión ambiental lo cual es un problema que ocasiona contaminación y poco interés con el entorno natural y el buen cumplimiento de las normas de protección del medio ambiente. Actualmente los comuneros no practican muchas de las costumbres, tradiciones y fiestas patronales ancestrales las cuales deben rescatarse por el valor que identifica a una comunidad. En las capacitaciones que les han sido brindadas algunas veces por Empresas Privadas, no asistieron debido a la premura del tiempo y por razones laborales en las cuales se desempeñan. Asimismo, se concluye que el Plan de Capacitación Comunitaria en Turismo Rural basados de los lineamientos propuestos por Mincetur en los siguientes aspectos: Económico, ambiental, social, cultural - educativo y en la oportunidad beneficia a la comunidad rural. Finalmente, se recomienda aprobar la ejecución del Plan de Capacitación Comunitaria en Turismo Rural, el cual permitirá impartir la formación en los comuneros en Agronegocios, producción y promover dichos talleres para valorar sus habilidades y conocimientos en ejecución de programas y proyectos de desarrollo socioculturales en el Área de Conservación Privada de Chaparrí

    Análisis del control y manejo de las cuentas de inventarios y activos fijos por el período comprendido entre el 1 de enero 2020 al 31 de marzo de 2021 en la Finca Miraflowers

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    Analizar la información de la cuenta de inventarios y activos fijos presentada por la empresa MIRAFLOWERS en el periodo comprendido entre enero de 2020 a marzo de 2021.La presente investigación busca determinar un camino claro y preciso para analizar el manejo de activos fijos e inventarios y así obtener información verídica y confiable. La metodología utilizada es un enfoque mixto y se aplican los métodos inductivos, deductivos y analíticos; por medio de recursos como: la entrevista, la observación y verificación de documentos presentados con relación a las existencias y propiedad, planta y equipo. Entre los referentes teóricos están Córdoba (2020) y Palacios (2013) quienes corroboran la importancia de llevar un control eficaz y eficiente de los activos fijos e inventarios. Dentro del ámbito contable, una adecuada administración de los recursos financieros brinda seguridad razonable a la empresa. De esta manera, se procede a evaluar la gestión interna del personal involucrado en las operaciones de estas cuentas objeto de estudio, para sugerir alternativas que contribuyan al mejoramiento de las actividades relacionadas con bienes y existencias. Los resultados obtenidos permiten determinar que existe ausencia de control interno, falta de aplicación de políticas en el registro y manejo de las mercancías, no disponen de registros adecuados de los activos fijos y las depreciaciones. En conclusión, es necesario implementar un sistema informático contable, un manual de políticas internas de acuerdo con la normativa vigente, elaborar un plan estratégico que determine funciones y responsabilidades en cada área, a fin de conseguir resultados financieros confiables.Licenciatur

    Responses of Jatropha curcas

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    Two greenhouse experiments were conducted to quantify growth responses of Jatropha curcas to a range of salt and drought stresses. Typical symptoms of salinity stress such as leaf edge yellowing were observed in all elevated salinity treatments and the degree of the foliar salt damage increased with the salinity of irrigation water. Total dry weight (DW) of Jatropha plants was reduced by 30%, 30%, and 50%, respectively, when irrigated with saline solutions at electrical conductivity of 3.0, 6.0, and 9.0 dS m−1 compared to that in the control. Leaf Na+ concentration was much higher than that observed in most glycophytes. Leaf Cl− concentrations were also high. In the drought stress experiment, plants were irrigated daily with nutrient solution at 100%, 70%, 50%, or 30% daily water use (DWU). Deficit irrigation reduced plant growth and leaf development. The DW of leaves, roots, and total were reduced in the 70%, 50%, and 30% DWU compared to the 100% DWU control treatment. In summary, salinity stress and deficit irrigation significantly reduced the growth and leaf development of greenhouse-grown Jatropha plants

    Common and divergent features in transcriptional control of the homologous small RNAs GlmY and GlmZ in Enterobacteriaceae

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    Small RNAs GlmY and GlmZ compose a cascade that feedback-regulates synthesis of enzyme GlmS in Enterobacteriaceae. Here, we analyzed the transcriptional regulation of glmY/glmZ from Yersinia pseudotuberculosis, Salmonella typhimurium and Escherichia coli, as representatives for other enterobacterial species, which exhibit similar promoter architectures. The GlmY and GlmZ sRNAs of Y. pseudotuberculosis are transcribed from σ54-promoters that require activation by the response regulator GlrR through binding to three conserved sites located upstream of the promoters. This also applies to glmY/glmZ of S. typhimurium and glmY of E. coli, but as a difference additional σ70-promoters overlap the σ54-promoters and initiate transcription at the same site. In contrast, E. coli glmZ is transcribed from a single σ70-promoter. Thus, transcription of glmY and glmZ is controlled by σ54 and the two-component system GlrR/GlrK (QseF/QseE) in Y. pseudotuberculosis and presumably in many other Enterobacteria. However, in a subset of species such as E. coli this relationship is partially lost in favor of σ70-dependent transcription. In addition, we show that activity of the σ54-promoter of E. coli glmY requires binding of the integration host factor to sites upstream of the promoter. Finally, evidence is provided that phosphorylation of GlrR increases its activity and thereby sRNA expression

    A IMPORTÂNCIA DAS PLANTAS MEDICINAIS PARA A CONSTRUÇÃO DO CONHECIMENTO EM BOTÂNICA EM UMA ESCOLA PÚBLICA NO MUNICÍPIO DE BENJAMIN CONSTANT-AMAZONAS (BRASIL)

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    O ensino de Ciências é uma das bases para a valorização do conhecimento científico, pois abrange uma infinidade de conceitos importantes para a formação cientifica dos alunos. A valorização do conhecimento popular que os alunos trazem sobre as plantas medicinais potencializa o interesse destes sobre os conhecimentos científicos. Com isso, o presente trabalho teve como objetivo sensibilizar o corpo discente e docente da Escola Estadual Imaculada Conceição, no município de Benjamin Constant-AM, para a importância do conhecimento dessas espécies vegetais no espaço escolar por meio da construção de uma horta. As atividades inicialmente foram desenvolvidas com alunos do ensino médio da Educação de Jovens e Adultos (EJA) consistindo nas seguintes etapas: execução de palestras educativas sobre as espécies vegetais; coleta de material proveniente de reutilização (garrafas plásticas); implantação da horta (preparo da terra, solo e plantio de sementes e mudas de plantas medicinais e condimentares; monitoramento de crescimento, irrigação e limpeza das hortas ecológicas); elaboração dos resultados por meio de cartilhas, banners e outras formas de divulgação em congressos nacionais. Na coleta e na análise dos dados, foram utilizadas as seguintes estratégias: observações participantes e análise documental. Este trabalho teve grande importância para a comunidade escolar envolvida. Levar propostas que associem o ensino de botânica, a educação ambiental e o saber popular sobre plantas para o contexto escolar é imprescindível, pois esse cruzamento de conceitos nos permite melhorar a atuação do ser humano como um cidadão consciente ambientalmente e que tenha atitudes sustentáveis em se tratando da preservação do meio ambiente. Palavras-chave: Conhecimento Científico. Conhecimento Popular. Educação Ambiental. THE IMPORTANCE OF MEDICINAL PLANTS FOR THE CONSTRUCTION OF BOTANICAL KNOWLEDGE IN A PUBLIC SCHOOL IN THE MUNICIPALITY OF BENJAMIN CONSTANT-AM   ABSTRACT: Science education is one of the bases for the valorization of scientific knowledge, since it covers a multitude of concepts important for the scientific formation of students. The appreciation of the popular knowledge that students bring about medicinal plants enhances their interest in scientific knowledge. The objective of this study was to sensitize the student and teaching staff of the Immaculate Conception State School, in the municipality of Benjamin Constant-AM, to the importance of knowledge of these plant species in the school space through the construction of a vegetable garden. The activities were initially developed with high school students of Youth and Adult Education (EJA) consisting of the following stages: educational lectures on plant species; collection of material from re-use (plastic bottles); implementation of the garden (land preparation, soil and planting of seeds and seedlings of medicinal plants and condiments, monitoring of growth, irrigation and cleaning of ecological gardens); elaboration of results through booklets, banners and other forms of dissemination in national congresses. In the data collection and analysis, the following strategies were used: participant observations and documentary analysis. This work had great importance for the school community involved. To carry out proposals that associate the teaching of botany, environmental education and popular knowledge about plants for the school context is essential, since this cross-fertilization of concepts allows us to improve the human being's performance as an environmentally conscious citizen and to have sustainable attitudes in dealing with the preservation of the environment. Keywords: Scientific Knowledge. Popular Knowledge. Environmental Education

    A haemagglutination test for rapid detection of antibodies to SARS-CoV-2

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    Serological detection of antibodies to SARS-CoV-2 is essential for establishing rates of seroconversion in populations, and for seeking evidence for a level of antibody that may be protective against COVID-19 disease. Several high-performance commercial tests have been described, but these require centralised laboratory facilities that are comparatively expensive, and therefore not available universally. Red cell agglutination tests do not require special equipment, are read by eye, have short development times, low cost and can be applied at the Point of Care. Here we describe a quantitative Haemagglutination test (HAT) for the detection of antibodies to the receptor binding domain of the SARS-CoV-2 spike protein. The HAT has a sensitivity of 90% and specificity of 99% for detection of antibodies after a PCR diagnosed infection. We will supply aliquots of the test reagent sufficient for ten thousand test wells free of charge to qualified research groups anywhere in the world

    Adenovirus-5-Vectored P. falciparum Vaccine Expressing CSP and AMA1. Part B: Safety, Immunogenicity and Protective Efficacy of the CSP Component

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    Background: A protective malaria vaccine will likely need to elicit both cell-mediated and antibody responses. As adenovirus vaccine vectors induce both these responses in humans, a Phase 1/2a clinical trial was conducted to evaluate the efficacy of an adenovirus serotype 5-vectored malaria vaccine against sporozoite challenge.\ud \ud Methodology/Principal Findings: NMRC-MV-Ad-PfC is an adenovirus vector encoding the Plasmodium falciparum 3D7 circumsporozoite protein (CSP). It is one component of a two-component vaccine NMRC-M3V-Ad-PfCA consisting of one adenovector encoding CSP and one encoding apical membrane antigen-1 (AMA1) that was evaluated for safety and immunogenicity in an earlier study (see companion paper, Sedegah et al). Fourteen Ad5 seropositive or negative adults received two doses of NMRC-MV-Ad-PfC sixteen weeks apart, at 1x1010 particle units per dose. The vaccine was safe and well tolerated. All volunteers developed positive ELISpot responses by 28 days after the first immunization (geometric mean 272 spot forming cells/million[sfc/m]) that declined during the following 16 weeks and increased after the second dose to levels that in most cases were less than the initial peak (geometric mean 119 sfc/m). CD8+ predominated over CD4+ responses, as in the first clinical trial. Antibody responses were poor and like ELISpot responses increased after the second immunization but did not exceed the initial peak. Pre-existing neutralizing antibodies (NAb) to Ad5 did not affect the immunogenicity of the first dose, but the fold increase in NAb induced by the first dose was significantly associated with poorer antibody responses after the second dose, while ELISpot responses remained unaffected. When challenged by the bite of P. falciparum-infected mosquitoes, two of 11 volunteers showed a delay in the time to patency compared to infectivity controls, but no volunteers were sterilely protected.\ud \ud Significance: The NMRC-MV-Ad-PfC vaccine expressing CSP was safe and well tolerated given as two doses, but did not provide sterile protection
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