Síntese e impregnação de peneiras moleculares Fe MCM-41 derivada de sílica da casca do arroz

The mesoporous molecular sieves of the MCM-41 and FeMCM-41 type are considered promissory as support for metals used as catalysts in oil-based materials refine processes and as adsorbents for environmental protection proposes. In this work MCM-41 and FeMCM41 were synthesized using rice husk ash - RHA as alternative to the conventional silica source. Hydrothermal synthesis was the method chosen to prepare the materials. Pre-defined synthesis parameters were 100°C for 168 hours, later the precursor was calcinated at 550°C for 2 hours under nitrogen and air flow. The sieves containing different proportions of iron were produced by two routes: introduction of iron salt direct synthesis; and a modification post synthesis consisting in iron salt 1 % and 5% impregnation in the material followed by thermal decomposition. The molecular sieves were characterized by X ray diffraction XRD, Fourier transform infrared spectroscopy FT-IR, X ray fluorescence spectroscopy XFR, scanning electronic microscopy SEM, specific surface area using the BET method, Termogravimetry TG. The kinetic model of Flynn Wall was used with the aim of determining the apparent activation energy of the surfactant remove (CTMABr) in the MCM- 41 porous. The analysis made possible the morphology characterization, identifying the presence of hexagonal structure typical for mesoporous materials, as well as observation of the MCM41 and iron of characteristic bands.

Síntese e caracterização de peneiras moleculares mesoporosas do tipo MCM-41 e AlMCM-41 a partir de fontes alternativas de sílica e de alumínio

The mesoporous molecular sieves of MCM-41 and AlMCM-41 type are considered as promising support for metal in the refining processes of petroleum-based materials as catalysts and adsorbents for environmental protection. In this work the molecular sieves MCM-41 and AlMCM-41 were synthesized by replacing the source of silica conventionally used, for quartz, an alternative and abundant, and the use of waste from the production of diatomaceous earth, an aluminum-silicate, as a source aluminum, due to abundant reserves of diatomaceous earth in the state of Rio Grande do Norte in the city of Ceará-Mirim, with the objective of producing high-value materials that have similar characteristics to traditional commercial catalysts in the market. These materials were synthesized by the method of hydrothermal synthesis at 100 º C for 7 days and subjected to calcination at 500 º C for 2 hours under flow of nitrogen and air. The molecular sieves were characterized by X-ray diffraction (XRD), differential thermal analysis (DTA) and thermogravimetric analysis (TG), adsorption of N2 (BET and BJH methods), spectroscopy in the infra red (FTIR), microscopy scanning electron (SEM) and transmission electron microscopy (TEM). The analysis indicated that the synthesized materials showed characteristic hexagonal structure of mesopores materials with high specific surface area and sort and narrow distribution of size of pores

Preparação e caracterização de catalisadores à base de titânio suportado em MCM-41 para produção de compostos oxigenados através da pirólise catalítica do capim elefante

In recent years, the area of advanced materials has been considerably, especially when it comes to materials for industrial use, such as is the case with structured porosity of catalysts suitable for catalytic processes. The use of catalysts combined with the fast pyrolysis process is an alternative to the oxygenate production of high added value, because, in addition to increasing the yield and quality of products, allows you to manipulate the selectivity to a product of interest, and therefore allows greater control over the characteristics of the final product. Based on these arguments, in this work were prepared titanium catalysts supported on MCM-41 for use in catalytic pyrolysis of biomass, called elephant grass. The reactions of pyrolysis of biomass were performed in a micro pyrolyzer, Py-5200, coupled to GC / MS, the company CDS Corporation, headquartered in the United States. The catalysts Ti-MCM-41 in different molar ratios were characterized by XRD, TG / DTG, FT-IR, SEM, XRF, UV-visible adsorption of nitrogen and the distribution of particle diameter and specific surface area measurement by the BET method. From the catalytic tests it was observed that the catalysts synthesized showed good results for the pyrolysis reaction.The main products were obtained a higher yield of aldehydes, ketones and furan. It was observed that the best reactivity is a direct function of the ratio Si/Ti, nature and concentration of the active species on mesoporous supports. Among the catalysts Ti-MCM-41 (molar ratio Si / Ti = 25 and 50), the ratio Si / Ti = 25 (400 ° C and 600 ° C) favored the cracking of oxygenates such as acids , aldehydes, ketones, furans and esters. Already the sample ratio Si / Ti = 50 had the highest yield of aromatic oxygenates

Reforma a seco de metano com catalisadores Ni/MCM-41 sintetizados a partir de fontes alternativas de sílica

The production of synthesis gas has received renewed attention due to demand for renewable energies to reduce the emissions of gases responsible for enhanced greenhouse effect. This work was carried out in order to synthesize, characterize and evaluate the implementation of nickel catalysts on MCM-41 in dry reforming reactions of methane. The mesoporous molecular sieves were synthesized using as silica sources the tetraethyl orthosilicate (TEOS) and residual glass powder (PV). The sieves were impregnated with 10% nickel to obtain the metallic catalysts (Ni/MCM-41). These materials were calcined and characterized by Thermogravimetric Analysis (TG), Infrared spectroscopy (FTIR), X-ray Diffraction (XRD), Temperature-Programmed Reduction (TPR) and N2 Adsorption/Desorption isotherms (BET/BJH). The catalytic properties of the samples were evaluated in methane dry reforming with CO2 in order to produce synthesis gas to be used in the petrochemical industry. The materials characterized showed hexagonal structure characteristic of mesoporous material MCM-41 type, being maintained after impregnation with nickel. The samples presented variations in the specific surface area, average volume and diameter of pores based on the type of interaction between the nickel and the mesoporous support. The result of the the catalytic tests showed conversions about 91% CO2, 86% CH4, yelds about 85% CO and 81% H2 to Ni/MCM-41_TEOS_C, and conversions about 87% CO2, 82% CH4, yelds about 70% CO and 59% H2 to Ni/MCM-41_PV_C. The similar performance confirms that the TEOS can be replaced by a less noble materials

Degradacao termica e catalitica da borra oleosa de Petroleo com materiais nanoestruturados al-mcm-41 e AL-SBA-15

Aiming to reduce and reuse waste oil from oily sludge generated in large volumes by the oil industry, types of nanostructured materials Al-MCM-41 and Al-SBA-15, with ratios of Si / Al = 50, were synthesized , and calcined solids used as catalysts in the degradation of oily sludge thermocatalytic oil from oilfield Canto do Amaro, in the state of Rio Grande do Norte. Samples of nanostructured materials were characterized by thermogravimetric analysis (TG / DTG), X-ray diffraction (XRD), scanning electron microscopy (SEM), absorption spectroscopy in the infrared Fourier transform (FT-IR) and adsorption nitrogen (BET). The characterization showed that the synthesized materials resulted in a catalyst nanostructure, and ordered pore diameter and surface area according to existing literature. The oily sludge sample was characterized by determining the API gravity and sulfur content and SARA analysis (saturates, aromatics, resins and asphaltenes). The results showed a material equivalent to the average oil with API gravity of 26.1, a low sulfur content and considerable amount of resins and asphaltenes, presented above in the literature. The thermal and catalytic degradation of the oily sludge oil was performed from room temperature to 870 ° C in the ratios of heating of 5, 10 and 20 ° C min-1. The curves generated by TG / DTG showed a more accelerated degradation of oily sludge when it introduced the nanostructured materials. These results were confirmed by activation energy calculated by the method of Flynn-Wall, in the presence of catalysts reduced energy, in particular in the range of cracking, showing the process efficiency, mainly for extraction of lightweight materials of composition of oily sludge, such as diesel and gasoline

A saúde psíquica de quem faz saúde: uma análise crítica sobre a humanização direcionada ao profissional de saúde

It is noticeable that pressure, tension and overwork are frequent in health professionals routine. The work related to the ward area demands deep attention and surveillance. Because of that, it is essential to have a specific look at the humanization directed at health professionals, considering that taking care of other human beings is the essence of their job. This study has analyzed the psychic health levels, as well as the stress health professionals are submitted to, providing a debate about the humanization in 06 public hospitals (03 of them awarded by actions of humanization, and 03 not awarded) in Rio Grande do Norte state, Brazil. A study with 126 active health professionals (doctors, nurses, psychologists, nutritionists and social workers) in ward areas in their respective institutions was carried out. The thesis presented, with multi-disciplinary characteristic, counted on the support of statisticians (to calculate samples and data analysis), psychologists, social workers and administrators (linked to the human resources sector in each hospital). A cross-sectional study was performed, taking into consideration both quantitative and qualitative factors. The tools used for that were a semistructured questionnaire with socio-demographic characteristics, work and humanization; Lipp's Stress Symptoms Inventory for Adults (ISSL), and the Goldberg s General Health Questionnaire (QSG). The workers are predominantly women (84,9%), married (54,8%), between 46 and 55 years old (40,5%), working in the same institution for more than 20 years (22,2%), and between 16 and 20 years (20,6%), respectively. They work 40 hours a week (71,4%) and have multiple jobs (61,9%). Although most of these individuals global psychic health is in a good level, there are a significant number of people that is gradually getting worse concerning psychic stress (F1) showed by QSG (54,7%), and stress showed by ISSL(42,1%). Observing the categories, nurses (41,5%). Nutritionists (20,8%), doctors and social workers (18,9%), were among the most affected. About general health (F6), 63% of the awarded hospitals and 70% of the not awarded ones, presented good health levels (ranging from 5 to 50%). It was also noticed that, in the groups mentioned above, 25 and 20% respectively, were inserted in scores between 55 to 90%, what means that they are in worsening phase. The fact that the hospital is awarded or well recognized doesn t interfere in health professionals stress level and in their psychic health. Through what was heard from these individuals, it was possible to verify that they know little about humanization, once few of them identify or know that the service they offer is in an adoption process by Ministerial Policies. It was also detected the necessity of developing actions aimed at worker s health. Such results showed the importance of have more investments in programs that are directed to workers well-being, because they deal with other people s health and it is known that it is difficult for them to offer high-quality assistance if there are not suitable physical, psychological and material conditions to help them develop their jobs. As a warning, it is fair to say that investments in actions that provide humanized care to health professionals, mainly concerning preventive care for their health and life quality in their work

Custo social de oportunidade na trajetória de acesso ao ensino superior: o caso dos ingressantes na UFRN nos vestibulares de 2006 a 2010

Access is a problem of higher education in Brazil that has existed since the formalization of this has occurred since the installation of the Portuguese court in Brazil in 1808. Only 10% of young people between 18 and 24 years of age attending this level of education in 2000, arriving in 2010 just 15%, far from that determined the National Education Plan in 2001, triple that percentage by the year 2010. In addition, a majority of seats of public HEIs is populated by students from the private network, especially in high-demand courses. In this context, this study aims to identify the costs related to the trajectories of students who were successful in the vestibular UFRN editions from 2006 to 2010. Presents an overview of higher education in Brazil, a brief history of vestibular, as well as new forms of access, and some of the policies to expand such access, highlighting the argument Inclusion UFRN. Focusing on the theme of the paper presents the concepts of opportunity costs and social. After collecting data through a questionnaire and consultation of databases COMPERVE was developed to search for a descriptive and analytical, with the participation of 3,995 students, of whom 1642 (41.1%) had completed secondary education in schools public, and 2,078 (52%) in private schools. The profile indicates that 90% are single, about 50% are 21 years of age, are white and female. In the course of preparation for college entrance exams, 80% chose the course during or after completion of the last year of high school, and almost 70% said they had started preparing at that time. Findings related to the costs involved with this preparation indicate that, in most cases there were school fees and disbursements and workshops, and the purchase of books and other materials, with parents primarily responsible for this cost, the amount disbursed each month was up $ 300 for 64% of respondents and only 7% of them exceeded $ 1,000, the major non-financial costs were characterized by the following resignations: job opportunities (24%) or temporary work (20%) courses of languages (26%), leisure activities (48%), leisure travel (43%), and parties and / or shows (54%). Of social investments by the government, stand out in the tax waiver scholarships for study in private institutions, grant exemption from the registration fee of vestibular, the preparatory courses UFRN, and seminars by COMPERVE / UFRN with networks of high school. From the junction of the opportunity costs (private costs) and social costs (public costs), a new concept: the social opportunity cost, which measures the combined efforts of families and government to finance the opportunity to access higher education of an individual. This concept can and should be incorporated as a strategic vector for the sake of democratic university, which reflects the social model that is sought

Atuação da escola frente à violência: estudo comparativo entre duas instituiçoes de ensino

It is a descriptive, exploratory study, quantitative comparative approach, whose general objective was to analyze the violence at school in a comparative way in the context of two schools in Natal / RN. The specifics were to identify the types of manifestations of violence in the contexts of public and private schools, to identify the position of the leadership, teachers and school staff during and after the occurrence of manifestations of violence in the school environment, to identify measures to prevent violence within of schools. The results show that 68 of the 121 participants (56.20%) were female and 53 (43.80%) were male, 38 (31.40%) were between 40 and 49, 85 (70.2%) lived in the south of Natal (RN), 46 (38.02%) specialization, 68 (56.20%) were Catholic, 63 (52.07%) married, 41 (33.88%) received between 03 and 05 and 68 minimum wages (56.20%) were teachers, 51 (42.15%) 02 employees (01,65%) and directors, 46 (38.02%) providers had between 05 and 14 years and 11 months experience in teaching 70 (57.85%) less than five years in the job, 68 (56.20%) worked between 20 hours and 40 hours per week, 81 (16.30%) worked in the 9th grade of elementary school II. As for the sizing of violence, 111 (91.74%) respondents witnessed episodes of this event who work in the institution, 100 (82.64%) witnessed verbal violence, 87 (71.90%) called for parents when some event happenedviolent that it caused injury to students, 66 (54.55%) believed that family violence is the main reason for young people practiced bullying, 44 (38.98%) reported daily episodes of bullying, 64 (52.89% ) the event happens in the courtyard. Of the 37 victims of violence at school, 22 (59.45%) suffered verbal abuse, 18 (48.65%) experienced violence once a week, 36 (97.30%) were attacked by students, 104 (85.95 %) are able to differentiate the bad acts of bullying behavior, 28 (23.14%) separated the involved coordination and communicated verbally, 23 (19.00%) stated that the coordination of schools talked with parents about the aggressive behavior of the student. Regarding the actions taken to minimize bullying, 69 (57.02%) participated in any professional education process, 47 (38.84%) was the educational process at another institution, 49 (71.01%) took courses lasting 12 to 24 hours, 59 (48.76%) stated that interaction with parents and family was the most stimulated by the school to try to minimize and prevent the event and 116 (95.87%) participated in meetings at the institutions surveyed , 58 (50.00%) responded that the meetings took place every two months and 121 (100.00%) reported having no refresher course on school violence in the schools surveyed. We conclude that violence in schools has been expressed in any social class and that professionals are poorly prepared to deal with the situation. So we hope that education professionals through the reading of our study may realize that school violence takes place in any institution affecting the lives of all who make up the educational universe. It is extremely important that these professionals always seek to empower through knowledge so that they can develop strategies to prevent and minimize the bullying to change the reality of the workplace

Síntese, caracterização e aplicação de MCM-41 funcionalizado com diisopropilamina no processo de adsorção do dióxido de carbono

Emissions of CO2 in the atmosphere have increased successively by various mechanisms caused by human action, especially as fossil fuel combustion and industrial chemical processes. This leads to the increase in average temperature in the atmosphere, which we call global warming. The search for new technologies to minimize environmental impacts arising from this phenomenon has been investigated. The capture of CO2 is one of the alternatives that can help reduce emis ions of greenhouse gases. The CO2 can be captured through the process of selective adsorption using adsorbents for this purpose. Were synthesized by hydrothermal method, materials of the type MCM-41 and Al-MCM-41 in the molar ratio Si / Al equal to 50. The synthesis of gels were prepared from a source of silicon, sodium, water and aluminum in the case of Al-MCM-41. The period of synthesis of the materials was 5 days in autoclave at 100°C. After that time materials were filtered, washed and dried in greenhouse at 100 º C for 4 hours and then calcined at 450 º C. Then the calcined material was functionalized with the Di-isopropylamine (DIPA) by the method of wet impregnation. We used 0.5 g of material mesopores to 3.5 mL of DIPA. The materials were functionalized in a closed container for 24 hours, and after this period were dried at brackground temperature for 2 hours. Were subsequently subjected to heat treatment at 250°C for 1 hour. These materials were used for the adsorption of CO2 and were characterized by XRD, FT-IR, BET / BJH, SEM, EDX and TG / DTG. Tests of adsorption of CO2 was carried out under the following conditions: 100 mg of adsorbent, temperature of 75°C under flow of 100 mL/min of CO2 for 2 hours. The desorption of CO2 was carried out by thermogravimetry from ambient temperature to 900ºC under flow of 25 mL min of He and a ratio of 10ºC/min. The difratogramas X-ray for the synthesized samples showed the characteristic peaks of MCM-41, showing that the structure of it was obtained. For samples functionalized there was a decrease of the intensities of these peaks, with a consequent reduction in the structural ordering of the material. However, the structure was preserved mesopores. The adsorption tests showed that the functionalized MCM-41 is presented as a material promising adsorbent, for CO2 capture, with a loss of mass on the desorption CO2 of 7,52%, while that in Al-MCM- 41 functionalized showed no such loss

Síntese, caracterização e aplicação do MCM-41 e A1-MCM-41 na pirólise do resíduo atmosférico de petróleo

In present work, mesoporous materials of the M41S family were synthesized, which were discovered in the early 90s by researchers from Mobil Oil Corporation, thus allowing new perspectives in the field of catalysis. One of the most important members of this family is the MCM-41, which has a hexagonal array of mesopores with pore diameters ranging from 2 to 10 nm and a high surface area, enabling it to become very promising for the use as a catalyst in the refining of oil in the catalytic cracking process, since the mesopores facilitate the access of large hydrocarbon molecules, thereby increasing the production of light products, that are in high demand in the market. The addition of aluminum in the structure of MCM-41 increases the acidity of the material, making it more beneficial for application in the petrochemical industry. The mesoporous materials MCM-41 and Al-MCM-41 (ratio Si / Al = 50) were synthesized through the hydrothermal method, starting with silica gel, NaOH and distilled water. CTMABr was used as template, for structural guiding. In Al-MCM-41 the same reactants were used, with the adding of pseudoboehmite (as a source of aluminum) in the synthesis gel. The syntheses were carried out over a period of four days with a daily adjustment of pH. The optimum conditions of calcination for the removal of the organic template (CTMABr) were discovered through TG / DTG and also through analysis by XRD, FTIR and Nitrogen Adsorption. It was found that both the method of hydrothermal synthesis and calcination conditions of the studies based on TG were promising for the production of mesoporous materials with a high degree of hexagonal array. The acidic properties of the materials were determined by desorption of n-butylamine via thermogravimetry. One proved that the addition of aluminum in the structure of MCM-41 promoted an increase in the acidity of the catalyst. To check the catalytic activity of these materials, a sample of Atmospheric Residue (RAT) that is derived from atmospheric distillation of oil from the Pole of Guamaré- RN was used. This sample was previously characterized by various techniques such as Thermogravimetry, FTIR and XRF, where through thermal analysis of a comparative study between the thermal degradation of the RAT, the RAT pyrolysis + MCM-41 and RAT + Al- MCM-41. It was found that the Al-MCM-41 was most satisfactory in the promotion of a catalytic effect on the pyrolysis of the RAT, as the cracking of heavy products in the waste occurred at temperatures lower than those observed for the pyrolysis with MCM-41, and thereby also decreasing the energy of activation for the process and increasing the rates of conversion of residue into lighter products

Síntese e caracterização da peneira molecular MCM-41 contendo terras raras na dessulfurização, utilizando tiofeno como molécula sonda

Mesoporous molecular sieves of MCM-41 type are considered as promising support for metal in the refining processes of petroleum-based materials as catalysts and adsorbents for environmental protection. In this work, mesoporous molecular sieves MCM-41 were modified with different rare earth ions (La, Eu e Yb) for the obtaining nanostrutured materials with catalytic properties. The catalysts were synthesized by the hydrothermal method at 100oC for 120 h, presenting, all the samples, in the gel of synthesis molar ratio Si/Ln = 50. The obtained materials after calcination at 500oC for 2 h were characterized by XRD, surface area BET, TG/DTG, FTIR, and hydrothermal stability at 700ºC. The XRD analysis of the catalysts indicated that the materials containing rare earth presented characteristic hexagonal structure of the mesoporous materials of the type MCM-41. The TG curves showed that the decomposition of the structural template occurs in the materials at temperatures lower than 500oC. The samples presented variations as the specific superficial area, average diameter of pores and thickness of the silica wall, as a function of the nature of the rare earth impregnated in the mesoporous material. Hydrotermal stability was evaluated through the exposition of the materials to water vapour at 700°C. The thiophene adsorptions reach a maximum at 80% of conversion and incorporation of the rare earths showed influence in the process. Adsorption capacity followed the sequence: Yb-MCM-41 < La-MCM-41 < Eu-MCM-41 < MCM-41

Avaliação da remoção de hidrocarbonetos aromáticos (BTEX) em águas utilizando materiais nanoestruturados do tipo Ti-MCM-41

Volatile Organic Compounds are pollutants coming mainly from activities that use fossil fuels. Within this class are the BTEX (benzene, toluene, ethylbenzene and xylenes) compounds that are considered hazardous. Among the various existing techniques for degradation of pollutants, there is advanced oxidation using H2O2 generating hidoxil radical ( OH). In this work, the mesoporous material of MCM-41 was synthesized by hydrothermal method and then was used as support, the impregnation of titanium by the method of synthesis with excess solvent to obtain the catalyst Ti-MCM-41. The catalyst was used in the reaction catalyzed removal of BTEX in water using H2O2 as oxidant. The materials were characterized by: XRD, TG/DTG, FTIR, nitrogen adsorption-desorption and FRX-EDX, in order to verify the method of impregnation of the mesoporous titanium support was effective. Catalytic tests were carried out in reactors of 20 mL containing BTEX (100.0 μg/L), H2O2 (2.0 M) and Ti-MCM-41 (2.0 g/L) in acid medium. The reaction occurred for 5 h at 60 °C and analysis were performed by gas chromatography with photoionization detector and static headspace sampler. The characterizations have proven the effectiveness of the synthesis method used and the incorporation of titanium lt in the support. The catalytic tests showed satisfactory results with conversion of more than 95 % for the studied compounds, where the catalyst 48% Ti-MCM-41 showed a higher removal efficiency of the compounds under study

Estudo cinético da degradação térmica e catalítica de petróleo pesado usando Al-MCM-41

The mesoporous nanostructured materials have been studied for application in the oil industry, in particular Al-MCM-41, due to the surface area around 800 to 1.000 m2 g-1 and, pore diameters ranging from 2 to 10 nm, suitable for catalysis to large molecules such as heavy oil. The MCM-41 has been synthesized by hydrothermal method, on which aluminum was added, in the ratio Si/Al equal to 50, to increase the generation of active acid sites in the nanotubes. The catalyst was characterized by X-ray diffraction (XRD), surface area by the BET method and, the average pore volume BJH method using the N2 adsorption, absorption spectroscopy in the infrared Fourier Transform (FT-IR) and determination of surface acidity with application of a probe molecule - n-butylamine. The catalyst showed well-defined structural properties and consistent with the literature. The overall objective was to test the Al-MCM-41 as catalyst and thermogravimetric perform tests, using two samples of heavy oil with API º equal to 14.0 and 18.5. Assays were performed using a temperature range of 30-900 ° C and heating ratios (β) ranging from 5, 10 and 20 °C min-1.The aim was to verify the thermogravimetric profiles of these oils when subjected to the action of the catalyst Al- MCM-41. Therefore, the percentage ranged catalyst applied 1, 3, 5, 10 and 20 wt%, and from the TG data were applied two different kinetic models: Ozawa-Flynn-Wall (OFW) and Kissinger-Akahrira-Sunose (KAS).The apparent activation energies found for both models had similar values and were lower for the second event of mass loss known as cracking zone, indicating a more effective performance of Al-MCM-41 in that area. Furthermore, there was a more pronounced reduction in the value of activation energy for between 10 and 20% by weight of the oil-catalyst mixture. It was concluded that the Al-MCM-41 catalyst has applicability in heavy oils to reduce the apparent activation energy of a catalyst-oil system, and the best result with 20% by weight of Al-MCM-41