Cinética de extração de óleo de mamona empregando etanol como solvente

The sensitization for energy issues and environmental resulting from burning fossil fuels encourage the search for materials, inputs and renewable sources of energy. The biofuel is one of these renewable sources and is produced from vegetable oils extracted from raw material such as castor (Ricinus communis). It has been investigated as a raw material due to the high oil content in the seed, the possibility of plantations in regions with water deficit and high agricultural productivity. In front of the possibility of developing a simplified process for the production of biodiesel, such as in situ transesterification, which avoids the previous separation of the oil existing in the micelle, the present work aims to evaluate the kinetic behavior of extraction from castor oil using ethanol as solvent. In this context, experimental data were obtained about the kinetic from castor oil using ethanol in several conditions of temperature, as well as, fitting mathematical models able to describe the kinetic of the system castor-oil-ethanol. The castor seed used in the work were characterized about its humidity, oil content and acidity, having been obtained 4.86 %, 43.3 % and 2.1 %, respectively. The experiments were carried out in batch using sealed Erlenmeyer flasks in a thermostatic bath with reciprocal agitation to investigate the extraction process at different temperatures (25, 35 and 45 ºC) and solid-liquid ratio equal to 0.08 (g/ml). The percentage extractions were quantified in times of 15, 30, 45, 60, 120, 180, 240, 300, 480, 600 and 1440 min. For description of kinetics extraction, the fit of three different kinetic models to the experimental data was tested, pseudo-first order (PFO), pseudo-second order (PSO) and Patricelli. From the calculation of the corrected Akaike information criterion (AICc), the PSO model was the one that best described the extraction kinetics. In this way, the results obtained in this work contribute to expand the knowledge about the extraction process of castor oil with ethanol as solvent.A sensibilização para questões energéticas e ambientais decorrentes da queima de combustíveis fósseis incentivou a busca por materiais, insumos e fontes renováveis de energias. O biocombustível é uma dessas fontes renováveis e é produzido a partir de óleos vegetais extraídos de matérias primas como a mamona (Ricinus communis). Ela tem sido investigada como matéria-prima devido ao alto teor de óleo na semente, a possibilidade de plantio em regiões com déficit hídrico e à sua elevada produtividade agrícola. Diante da possibilidade de desenvolvimento de um processo simplificado para a produção de biodiesel, como o de transesterificação in situ, que evita a separação prévia do óleo presente na micela, o presente trabalho busca avaliar o comportamento cinético da extração do óleo de mamona empregando etanol como solvente. Nesse contexto, foram obtidos dados experimentais sobre a cinética da extração de óleo de mamona com etanol em diferentes condições de temperatura, bem como, ajustar modelos matemáticos capazes de descrever a cinética do sistema mamona-óleo-etanol. As sementes de mamona empregadas no trabalho foram caracterizadas acerca de sua umidade, teor de óleo e acidez, tendo sido obtido 4,86 %, 43,3 % e 2,1 %, respectivamente. Os experimentos foram realizados em batelada utilizando frascos erlenmeyer selados em banho termostático com agitação recíproca para investigar o processo de extração em diferentes temperaturas (25, 35 e 45 ºC) e razão sólido-líquido 0,08 (g/mL). As extrações percentuais foram quantificadas em tempos de 15, 30, 45, 60, 120, 180, 240, 300, 480, 600 e 1440 min. Para descrição da cinética de extração, foi testado o ajuste de três modelos cinéticos diferentes aos dados experimentais, pseudo-primeira ordem (PFO), pseudo-segunda ordem (PSO) e Patricelli. A partir do cálculo do critério de informação de Akaike corrigido (AICc) o modelo PSO foi o que melhor descreveu a cinética de extração. Deste modo, os resultados obtidos neste trabalho contribuem para ampliação dos conhecimentos acerca do processo de extração de óleo de mamona com etanol como solvente

A utilização de resíduos agroindustriais para adsorção do corante azul de metileno: uma breve revisão / The use of agro-industrial waste for adsorption of the blue dye of methylene: a brief review

No âmbito industrial há uma crescente preocupação com o setor têxtil, em especial com os efluentes gerados por ele, em virtude de seu potencial como fonte de contaminação de águas. Nestes efluentes estão presentes inúmeros corantes, dentre os quais evidencia-se o azul de metileno (AM), amplamente usado em função de suas características. Portanto, é essencial realizar um tratamento adequado dos efluentes, a fim de possibilitar seu lançamento em corpos receptores sem comprometê-los. Dentre as alternativas de tratamento disponíveis, a adsorção com carvão ativado ganha destaque pela elevada eficiência, mas apresenta-se muito custosa, motivo pelo qual buscam-se outros materiais com capacidade adsortiva e, sob esse viés surgem os resíduos agroindustriais. Estes são utilizados in natura ou transformados em carvão ativado, através de ativação física ou química. Devido a extensão territorial brasileira, encontram-se uma ampla gama de resíduos que vêm sendo pesquisados como adsorventes, dentre os quais destacam-se a serragem de madeira, cascas de frutas, sementes de frutas e amêndoas, bagaço de frutas, cana-de-açúcar, resíduos de cereais e leguminosas como palha, sabugo, bainha e tortas, além de resíduos de erva-mate. Os dados das pesquisas mostram resultados satisfatórios para os adsorventes alternativos e dessa maneira, além da remoção eficiente do corante, também é possível reduzir custos do processo de tratamento, agregando valor a um resíduo e solucionando-se uma problemática ambiental, tanto na questão de destinação de resíduos, bem como no tratamento de efluentes

Adsorção de corante vermelho do congo empregando carvão ativado de casca de arroz

The consumption pattern of contemporary society has created challenges in seeking solutions to mitigate the inherent environmental impacts. Among these impacts are the contamination of water bodies by organic pollutants, such as dyes. In this way, several alternatives for wastewater treatment are sought, such as adsorption. For dyes, the adsorption technology has been considered promising due to its high efficiency, low cost and simplicity of operation. Thus, the present work aims to investigate the use of activated charcoal from rice husk for the treatment of Congo red dye, through studies of the thermodynamic balance of the system and the adsorption kinetics. The equilibrium experiments were conducted at different initial concentrations (25, 50, 100 and 150 mg L-1) and temperatures (25, 35 and 45 ° C). In the kinetic experiments, temperatures of 25, 35 and 45 ºC and initial concentrations of 50, 100 and 150 mg L-1 were used. In order to describe the adsorption isotherms, an integrated adjustment strategy for data from different temperatures was adopted, using the appropriate thermodynamic concepts. From the calculation of the corrected Akaike information criterion (AICc), the Langmuir model (AICc = 86.3) was determined to be the most appropriate to describe the adsorption balance. Thermodynamic parameters point to the phenomenon of physical adsorption in monolayer, with maximum adsorption capacity close to 160 mg g-1. For the study of adsorption kinetics, the mathematical models of Pseudo-First Order (PFO) and PseudoSecond Order (PSO) were tested, each employing different adjustment strategies to minimize the number of parameters. The most appropriate model was the PSO with coupling of the Langmuir isotherm model determined in the study (AICc = 127.4). In this way, the results obtained in this work contribute to the expansion of knowledge about the Congo red adsorption process using activated charcoal from rice biomass of rice husk and rational design of operation for the treatment of such effluent.O padrão de consumo da sociedade contemporânea tem gerado desafios na busca de soluções para mitigação dos inerentes impactos ambientais. Dentre esses impactos, estão a contaminação de corpos hídricos por poluentes orgânicos, como os corantes. Desta forma, buscam-se diversas alternativas de tratamento de águas residuárias, como a adsorção. Para os corantes, a tecnologia de adsorção vem sendo considerada promissora em função de apresentar alta eficiência, baixo custo e simplicidade de operação. Deste modo, o presente trabalho tem como objetivo investigar o uso de carvão ativado da casca de arroz para o tratamento do corante vermelho do congo, através de estudos do equilíbrio termodinâmico do sistema e da cinética de adsorção. Os experimentos de equilíbrio foram conduzidos em diferentes concentrações iniciais (25, 50, 100 e 150 mg L-1) e temperaturas (25, 35 e 45 °C). Nos experimentos de cinética, foram empregadas temperaturas de 25, 35 e 45 ºC e concentrações iniciais de 50, 100 e 150 mg L-1. Para descrição das isotermas de adsorção, foi adotada estratégia de ajuste integrado dos dados de diferentes temperaturas, empregando os conceitos termodinâmicos apropriados. A partir do cálculo do critério de informação de Akaike corrigido (AICc) o modelo Langmuir (AICc = 86,3) foi determinado como o mais apropriado para descrever o equilíbrio de adsorção. Os parâmetros termodinâmicos apontam para o fenômeno de adsorção física em monocamada, com capacidade máxima de adsorção próxima a 160 mg g-1. Para o estudo da cinética de adsorção, foram testados os modelos matemáticos de Pseudo-Primeira Ordem (PFO) e Pseudo-Segunda Ordem (PSO), cada um deles empregando diferentes estratégias de ajuste para minimização do número de parâmetros. O modelo mais apropriado foi o PSO com acoplamento do modelo de isoterma de Langmuir determinado no trabalho (AICc = 127,4). Deste modo, os resultados obtidos neste trabalho contribuem para ampliação dos conhecimentos acerca do processo adsorção de vermelho do congo utilizando carvão ativado de biomassa vegetal da casca de arroz e dimensionamento racional de operação para o tratamento de tal efluente

SARS-CoV-2 vaccination modelling for safe surgery to save lives: data from an international prospective cohort study

Background Preoperative SARS-CoV-2 vaccination could support safer elective surgery. Vaccine numbers are limited so this study aimed to inform their prioritization by modelling. Methods The primary outcome was the number needed to vaccinate (NNV) to prevent one COVID-19-related death in 1 year. NNVs were based on postoperative SARS-CoV-2 rates and mortality in an international cohort study (surgical patients), and community SARS-CoV-2 incidence and case fatality data (general population). NNV estimates were stratified by age (18-49, 50-69, 70 or more years) and type of surgery. Best- and worst-case scenarios were used to describe uncertainty. Results NNVs were more favourable in surgical patients than the general population. The most favourable NNVs were in patients aged 70 years or more needing cancer surgery (351; best case 196, worst case 816) or non-cancer surgery (733; best case 407, worst case 1664). Both exceeded the NNV in the general population (1840; best case 1196, worst case 3066). NNVs for surgical patients remained favourable at a range of SARS-CoV-2 incidence rates in sensitivity analysis modelling. Globally, prioritizing preoperative vaccination of patients needing elective surgery ahead of the general population could prevent an additional 58 687 (best case 115 007, worst case 20 177) COVID-19-related deaths in 1 year. Conclusion As global roll out of SARS-CoV-2 vaccination proceeds, patients needing elective surgery should be prioritized ahead of the general population.The aim of this study was to inform vaccination prioritization by modelling the impact of vaccination on elective inpatient surgery. The study found that patients aged at least 70 years needing elective surgery should be prioritized alongside other high-risk groups during early vaccination programmes. Once vaccines are rolled out to younger populations, prioritizing surgical patients is advantageous

Effects of pre-operative isolation on postoperative pulmonary complications after elective surgery: an international prospective cohort study an international prospective cohort study

We aimed to determine the impact of pre-operative isolation on postoperative pulmonary complications after elective surgery during the global SARS-CoV-2 pandemic. We performed an international prospective cohort study including patients undergoing elective surgery in October 2020. Isolation was defined as the period before surgery during which patients did not leave their house or receive visitors from outside their household. The primary outcome was postoperative pulmonary complications, adjusted in multivariable models for measured confounders. Pre-defined sub-group analyses were performed for the primary outcome. A total of 96,454 patients from 114 countries were included and overall, 26,948 (27.9%) patients isolated before surgery. Postoperative pulmonary complications were recorded in 1947 (2.0%) patients of which 227 (11.7%) were associated with SARS-CoV-2 infection. Patients who isolated pre-operatively were older, had more respiratory comorbidities and were more commonly from areas of high SARS-CoV-2 incidence and high-income countries. Although the overall rates of postoperative pulmonary complications were similar in those that isolated and those that did not (2.1% vs 2.0%, respectively), isolation was associated with higher rates of postoperative pulmonary complications after adjustment (adjusted OR 1.20, 95%CI 1.05–1.36, p = 0.005). Sensitivity analyses revealed no further differences when patients were categorised by: pre-operative testing; use of COVID-19-free pathways; or community SARS-CoV-2 prevalence. The rate of postoperative pulmonary complications increased with periods of isolation longer than 3 days, with an OR (95%CI) at 4–7 days or ≥ 8 days of 1.25 (1.04–1.48), p = 0.015 and 1.31 (1.11–1.55), p = 0.001, respectively. Isolation before elective surgery might be associated with a small but clinically important increased risk of postoperative pulmonary complications. Longer periods of isolation showed no reduction in the risk of postoperative pulmonary complications. These findings have significant implications for global provision of elective surgical care. We aimed to determine the impact of pre-operative isolation on postoperative pulmonary complications after elective surgery during the global SARS-CoV-2 pandemic. We performed an international prospective cohort study including patients undergoing elective surgery in October 2020. Isolation was defined as the period before surgery during which patients did not leave their house or receive visitors from outside their household. The primary outcome was postoperative pulmonary complications, adjusted in multivariable models for measured confounders. Pre-defined sub-group analyses were performed for the primary outcome. A total of 96,454 patients from 114 countries were included and overall, 26,948 (27.9%) patients isolated before surgery. Postoperative pulmonary complications were recorded in 1947 (2.0%) patients of which 227 (11.7%) were associated with SARS-CoV-2 infection. Patients who isolated pre-operatively were older, had more respiratory comorbidities and were more commonly from areas of high SARS-CoV-2 incidence and high-income countries. Although the overall rates of postoperative pulmonary complications were similar in those that isolated and those that did not (2.1% vs 2.0%, respectively), isolation was associated with higher rates of postoperative pulmonary complications after adjustment (adjusted OR 1.20, 95%CI 1.05–1.36, p = 0.005). Sensitivity analyses revealed no further differences when patients were categorised by: pre-operative testing; use of COVID-19-free pathways; or community SARS-CoV-2 prevalence. The rate of postoperative pulmonary complications increased with periods of isolation longer than 3 days, with an OR (95%CI) at 4–7 days or ≥ 8 days of 1.25 (1.04–1.48), p = 0.015 and 1.31 (1.11–1.55), p = 0.001, respectively. Isolation before elective surgery might be associated with a small but clinically important increased risk of postoperative pulmonary complications. Longer periods of isolation showed no reduction in the risk of postoperative pulmonary complications. These findings have significant implications for global provision of elective surgical care

Measurements of the Total and Differential Higgs Boson Production Cross Sections Combining the H??????? and H???ZZ*???4??? Decay Channels at s\sqrt{s}=8??????TeV with the ATLAS Detector

Measurements of the total and differential cross sections of Higgs boson production are performed using 20.3~fb$^{-1}$ of $pp$ collisions produced by the Large Hadron Collider at a center-of-mass energy of $\sqrt{s} = 8$ TeV and recorded by the ATLAS detector. Cross sections are obtained from measured $H \rightarrow \gamma \gamma$ and $H \rightarrow ZZ ^{*}\rightarrow 4\ell$ event yields, which are combined accounting for detector efficiencies, fiducial acceptances and branching fractions. Differential cross sections are reported as a function of Higgs boson transverse momentum, Higgs boson rapidity, number of jets in the event, and transverse momentum of the leading jet. The total production cross section is determined to be $\sigma_{pp \to H} = 33.0 \pm 5.3 \, ({\rm stat}) \pm 1.6 \, ({\rm sys}) \mathrm{pb}$. The measurements are compared to state-of-the-art predictions.Measurements of the total and differential cross sections of Higgs boson production are performed using 20.3  fb-1 of pp collisions produced by the Large Hadron Collider at a center-of-mass energy of s=8  TeV and recorded by the ATLAS detector. Cross sections are obtained from measured H→γγ and H→ZZ*→4ℓ event yields, which are combined accounting for detector efficiencies, fiducial acceptances, and branching fractions. Differential cross sections are reported as a function of Higgs boson transverse momentum, Higgs boson rapidity, number of jets in the event, and transverse momentum of the leading jet. The total production cross section is determined to be σpp→H=33.0±5.3 (stat)±1.6 (syst)  pb. The measurements are compared to state-of-the-art predictions.Measurements of the total and differential cross sections of Higgs boson production are performed using 20.3 fb$^{-1}$ of $pp$ collisions produced by the Large Hadron Collider at a center-of-mass energy of $\sqrt{s} = 8$ TeV and recorded by the ATLAS detector. Cross sections are obtained from measured $H \rightarrow \gamma \gamma$ and $H \rightarrow ZZ ^{*}\rightarrow 4\ell$ event yields, which are combined accounting for detector efficiencies, fiducial acceptances and branching fractions. Differential cross sections are reported as a function of Higgs boson transverse momentum, Higgs boson rapidity, number of jets in the event, and transverse momentum of the leading jet. The total production cross section is determined to be $\sigma_{pp \to H} = 33.0 \pm 5.3 \, ({\rm stat}) \pm 1.6 \, ({\rm sys}) \mathrm{pb}$. The measurements are compared to state-of-the-art predictions