Eliminación de compuestos orgánicos volátiles en atmósferas cerradas mediante el uso de un material híbrido, zeolita-mof

128 páginas. Maestría en Ciencias e Ingeniería Ambientales.Ante los problemas de salud generados en el ser humano por la contaminación del aire en espacios cerrados, debida en gran parte por la presencia de compuestos orgánicos volátiles (COV’s) los cuales son generados por las actividades cotidianas y el uso de materiales en espacios interiores, es necesaria la implementación de soluciones eficientes y económicas para resolver esta problemática. En este trabajo de investigación se contribuyó a resolver dicha problemática, con el uso de un material híbrido, conformado por una zeolita natural y una estructura metal-orgánica con cerio, para adsorber y/o oxidar algunos compuestos orgánicos volátiles comúnmente encontrados en interiores, como son: formaldehído, tolueno y xilenos; con el uso del material híbrido se ha logrado tener un efecto sinérgico entre ambos materiales para una completa y efectiva oxidación de los contaminantes atmosféricos en espacios cerrados, con el fin último de proponer una posible solución que propicie una atmósfera limpia y saludable en espacios interiores en donde se desarrollan de manera cotidiana las actividades humanas.Given the health problems generated in humans by air pollution in indoor spaces, due in large part to the presence of volatile organic compounds (VOC’s) which are generated by daily activities and the use of materials in indoor spaces, it is necessary to implementation of efficient and economic solutions to solve this problem. This research work helped to solve this problem, with the use of a hybrid material, consisting of a natural zeolite and a metalorganic framework with cerium, to adsorb and/or oxidize some volatile organic compounds commonly found indoors, such as they are: formaldehyde, toluene and xylenes; with the use of the hybrid material it has been possible to have a synergistic effect between both materials for a complete and effective oxidation of air pollutants in this spaces, with the ultimate goal of proposing a possible solution that promotes a clean and healthy atmosphere in indoor spaces in where human activities develop daily.Consejo Nacional de Ciencia y Tecnología (México)

Síntesis de una estructura metal-orgánica con cerio

En la presente investigación se presenta la síntesis de una estructura metal-orgánica (MOF) tipo MOF-76 con cerio, sintetizado a diferentes tiempos de síntesis solvotermal con el objetivo de obtener el mayor rendimiento del material manteniendo su estructura, dicho material se empleará en un futuro con aplicaciones potenciales para la adsorción de compuestos orgánicos volátiles como el formaldehido, el tolueno oxilenos, comúnmente encontrados en ambientes cerrados. Se estudiaron tres diferentes tiempos de síntesis (30 min, 2 h y 20 h) a la temperatura de 140°C en cada una de las síntesis, los precursores empleados son: ácido trimésico, dimetilformamida y nitrato de cerio. Los materiales se caracterizaron por técnicas convencionales de SEM/EDS y FTIR y los resultados mostraron que el mayor rendimiento en peso se obtiene a 20 h pero con pérdida de su morfología. A dos horas de síntesis se obtiene un menor rendimiento y se conserva la morfología y estructura, por lo que sugerimos que éste es el tiempo óptimo de síntesis.In this research we present the synthesis of a metal-organic structure (MOF) type MOF-76 with cerium, synthesized at different times of solvothermal synthesis in arder to obtain the highest performance ofthe material while maintaining its structure, this material will be used in a future with potential applications for the adsorption of volatile organic compounds such as formaldehyde, toluene or xylenes, commonly found in indoor environments. Three different synthesis times were studied (30 min, 2 h and 20 h) at the temperature of 140 ºC in each of the syntheses, the precursors used are: trimesic acid, dimethylformamide and cerium nitrate. The materials were characterized by conventional techniques of SEM/EDS and FTIR and the results showed that the highest yield in weight is obtained at 20 h but with loss of morphology. After two hours of synthesis, a lower yield is obtained and the morphology and structure are conserved, so we suggest that this is the optimal synthesis time

Preparación de un material híbrido adsorbente

El objetivo de esta investigación es desarrollar un material híbrido para ser usado, en un futuro, como adsorbente y/o catalizador de compuestos orgánicos volátiles (COV´s), dicho material está conformado por una zeolita natural, que es un sustrato de estructura cristalina cuyas propiedades son ampliamente utilizadas en el tratamiento de COV’s y, por otra parte, por una estructura metal orgánica (MOF) compuesta de cerio, que también es sabido tiene excelentes propiedades como adsorbente; se busca lograr un efecto sinérgico entre ambos materiales, y que el material híbrido así conformado funcione primeramente como adsorbente y además como un catalizador con propiedades redox, que permita la oxidación de los COV´s en sustancias no tóxicas. Por lo que en esta propuesta se propone preparar un material híbrido eficiente y de bajo costo a partir el uso de una MOF con Ce y una zeolita natural, para una completa y efectiva oxidación de COV´s.The objective of this research is to develop a hybrid material to be used, in the future, as an adsorbent and/or catalyst of volatile organic compounds (VOC’s), said material is formed by a natural zeolite, which is a substrate of crystalline structure whose properties are widely used in the treatment of VOC’s and, on the other hand, by an organic metal structure (MOF) composed of cerium, which is also known to have excellent adsorbent properties. We want to achieve a synergistic effect between both materials, and that the hybrid material thus formed functions primarily as an adsorbent and also as a catalyst with redox properties, which allows the oxidation of VOC’s into non-toxic substances. So in this proposal it is proposed to prepare an efficient and low-cost hybrid material from the use of a MOF with Ce and a natural zeolite, for a complete and effective oxidation of VOC’s

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

Reduction of cardiac imaging tests during the COVID-19 pandemic: The case of Italy. Findings from the IAEA Non-invasive Cardiology Protocol Survey on COVID-19 (INCAPS COVID)

Background: In early 2020, COVID-19 massively hit Italy, earlier and harder than any other European country. This caused a series of strict containment measures, aimed at blocking the spread of the pandemic. Healthcare delivery was also affected when resources were diverted towards care of COVID-19 patients, including intensive care wards. Aim of the study: The aim is assessing the impact of COVID-19 on cardiac imaging in Italy, compare to the Rest of Europe (RoE) and the World (RoW). Methods: A global survey was conducted in May–June 2020 worldwide, through a questionnaire distributed online. The survey covered three periods: March and April 2020, and March 2019. Data from 52 Italian centres, a subset of the 909 participating centres from 108 countries, were analyzed. Results: In Italy, volumes decreased by 67% in March 2020, compared to March 2019, as opposed to a significantly lower decrease (p < 0.001) in RoE and RoW (41% and 40%, respectively). A further decrease from March 2020 to April 2020 summed up to 76% for the North, 77% for the Centre and 86% for the South. When compared to the RoE and RoW, this further decrease from March 2020 to April 2020 in Italy was significantly less (p = 0.005), most likely reflecting the earlier effects of the containment measures in Italy, taken earlier than anywhere else in the West. Conclusions: The COVID-19 pandemic massively hit Italy and caused a disruption of healthcare services, including cardiac imaging studies. This raises concern about the medium- and long-term consequences for the high number of patients who were denied timely diagnoses and the subsequent lifesaving therapies and procedures

Impact of COVID-19 on Diagnostic Cardiac Procedural Volume in Oceania: The IAEA Non-Invasive Cardiology Protocol Survey on COVID-19 (INCAPS COVID)

Objectives: The INCAPS COVID Oceania study aimed to assess the impact caused by the COVID-19 pandemic on cardiac procedure volume provided in the Oceania region. Methods: A retrospective survey was performed comparing procedure volumes within March 2019 (pre-COVID-19) with April 2020 (during first wave of COVID-19 pandemic). Sixty-three (63) health care facilities within Oceania that perform cardiac diagnostic procedures were surveyed, including a mixture of metropolitan and regional, hospital and outpatient, public and private sites, and 846 facilities outside of Oceania. The percentage change in procedure volume was measured between March 2019 and April 2020, compared by test type and by facility. Results: In Oceania, the total cardiac diagnostic procedure volume was reduced by 52.2% from March 2019 to April 2020, compared to a reduction of 75.9% seen in the rest of the world (p<0.001). Within Oceania sites, this reduction varied significantly between procedure types, but not between types of health care facility. All procedure types (other than stress cardiac magnetic resonance [CMR] and positron emission tomography [PET]) saw significant reductions in volume over this time period (p<0.001). In Oceania, transthoracic echocardiography (TTE) decreased by 51.6%, transoesophageal echocardiography (TOE) by 74.0%, and stress tests by 65% overall, which was more pronounced for stress electrocardiograph (ECG) (81.8%) and stress echocardiography (76.7%) compared to stress single-photon emission computerised tomography (SPECT) (44.3%). Invasive coronary angiography decreased by 36.7% in Oceania. Conclusion: A significant reduction in cardiac diagnostic procedure volume was seen across all facility types in Oceania and was likely a function of recommendations from cardiac societies and directives from government to minimise spread of COVID-19 amongst patients and staff. Longer term evaluation is important to assess for negative patient outcomes which may relate to deferral of usual models of care within cardiology