Cinética de la Adsorción de Plaguicidas en Compuestos de Grafeno: Una Revisión

The increase in the concentration of pesticides in bodies of water in recent years can be removed by adsorption. This review took the works from 2010 to 2022 considering as selection criteria work that had to be adsorption of some pesticide with graphene compounds and also their kinetics and adsorption isotherms have been studied mainly, separated into four stages: Research design, review, analysis, and finally the structuring and writing. When analyzing the works, it was found that the pH, initial concentration of the pesticide, volume, and adsorbent ratio, reaction temperature, contact time, temperature, π electron density, specific surface area, time for equilibrium state, and optimal conditions for the pyrolysis (it is an isolated case) are factors that can directly influence the kinetics of pesticides. This process is carried out by the formation of π bonds (as π, π-π, π-alkyl, π-alkaline, π-σ, π-stacked and T-shaped bonds), electrostatic and ionic interactions that allow the pesticide is adsorbed on the different graphene compounds with the help of atoms capable of donating electrons such as sulfur, nitrogen, oxygen, phosphorus or hydrogen bond precursors.El incremento de la concentración de plaguicidas en cuerpos de agua de los últimos años puede eliminarse por adsorción. Esta revisión se tomó los trabajos desde 2010 a 2022 considerando como criterios de selección trabajos se tuvo que sea adsorción de algún plagicida con compuestos de grafeno y además se haya estudiado su cinética e isotermas de adsorción pricipalmente, separadas en cuatro etapas: Diseño de la investigación, realización de la revisión, análisis y finalmente la estructuración y redacción. Al analizar los trabajos se encontró que el pH, concentración inicial del plaguicida, relación volumen y adsorbente, temperatura de reacción, tiempo de contacto, temperatura, densidad de electrones π, área superficial específica, tiempo para el estado de equilibrio y condiciones óptimas para la pirólisis (es caso aislado), son factores que pueden influir directamente la cinética de adsorción de los plaguicidas. Este proceso se lleva a cabo por la formación de enlaces π (como enlaces π, π-π, π-alquilo, π-alcalinos, π-σ, π-apiladas y en forma de T), interacciones electrostáticas e iónicas que permiten que el plaguicida se adsorba en los diferentes compuestos de grafeno ayudándose con los átomos capaces de donar electrones como el azufre, nitrógeno, oxígeno, fósforo o precursores de puentes de hidrógeno

Use of organic fertilizers in solar photo-Fenton process as potential technology to remove pineapple processing wastewater in Costa Rica

Background: This work studied the use of the organic fertilizers DTPA-Fe and EDDS-Fe as iron chelates for solar driven photo-Fenton process at natural pH. This process was proposed to investigate its performance on removing a mixture of agrochemicals (propiconazole, imidacloprid and diuron) from pineapple processing wastewater to obtain a suitable effluent to be reused in the agricultural sector. Methods: Experiments were carried out in a solar simulator with a stirred cylindric photoreactor, with a volume of 150 mL and controlled temperature (20°C). The first set of experiments was carried out with ultrapure water to determine optimal iron and H2O2 concentrations. The second was performed with simulated wastewater of pineapple processing. Results: The optimized operational conditions for both iron complexes were 10 mg L-1 of Fe (III) and 25 mg L-1 of H2O2, since more than 80% of micropollutants (MP) (at an initial concentration of 1 mg L-1 of each compound) were removed in only 20 min with both DTPA-Fe and EDDS-Fe. The effect of organic matter and inorganic salts on radicals scavenging and chelates stability was also investigated in the experiments performed with synthetic pineapple processing wastewater. The results disclosed differences depending on the iron complex. Nitrites were the principal component influencing the tests carried out with EDDS-Fe. While carbonates at low concentration only significantly affected the experiments performed with DTPA-Fe, they were the major influence on the MPs removal efficiency decrease. In contrast, the presence of Ca2+ and Mg2+ only influence on this last one. Finally, the results of phytotoxicity disclosed the suitability of treated effluent to be reused in the agricultural sector. Conclusions: This work demonstrated that solar powered photo-Fenton catalysed by iron fertilizer EDDS is a suitable technology for depolluting water streams coming from pineapple processing plants at circumneutral pH, and its subsequent reuse for crop irrigation

Efficient and reusable iron-zinc oxide catalyst for oxidative desulfurization of model fuel

In this study, Fe-ZnO catalyst synthesized via modified sol–gel technique with different Fe doping ratio (2, 3, and 5) wt% was explored for oxidative desulfurization (ODS) of model fuel. The sol-gel technique was adopted without the use of surfactants. The catalysts were characterized by several means of characterization techniques (TGA, XRD, FTIR, N2- physisorption, XPS, FESEM-EDX and NH3-TPD). The characterization results clearly showed that sol-gel technique is a suitable method to synthesize highly crystalline metal oxide materials with smaller particle size, higher surface area and tunable acidic properties. The ODS reaction conditions and Fe metal loading were found to influence the dibenzothiophene (DBT) removal efficiency. The catalytic ODS data showed that Fe-ZnO with 5 wt% of Fe catalyst is capable in total removal of DBT within shorter reaction time under mild reaction conditions in the presence of H2O2 as an oxidant. The catalyst is reusable for six consecutive cycles of reaction without regeneration steps and the characteristic of spent catalyst was confirmed with XRD and FTIR analysis. The close catalytic cycle involving H2O2 as an oxidant was shown through proposed mechanistic pathway

Anexo 7. Gastos ocasionados por la fragata San Joseph en Valdivia, La Concepción y Valparaíso de marzo a mayo de 1723

Gastos que ha causado la fragata de mi cargo Señor San Joseph y las Animas desde el día 14 de marzo que dio fondo en el puerto de Valdivia hasta el día 12 de mayo de 1723 años que salió de el de Valparaíso cargado para el del Callao En Valdivia se gastaron diez pesos de pescado en los 23 días que allí estuvimos por ser cuaresma y que comíamos los más abordo y los huéspedes precisos 10 p Por tres pesos que les di para comer a seis hombres el día que me llevaron en la góndola y el día que me tr..

El desarrollo cognoscitivo piagetiano y su relación con los documentos referenciales de gestión educativa, en el nivel primario, institución educativa “Divino Corazón de Jesús”, distrito Paucarpata, Región Arequipa, 2017.

TesisLa investigación titulada El desarrollo cognoscitivo piagetiano y su relación con los documentos referenciales de gestión educativa, en el nivel primario, institución educativa “Divino Corazón de Jesús”, distrito Paucarpata, Región Arequipa, 2017, tiene como objetivo general, determinar la relación entre el desarrollo cognoscitivo piagetiano y los documentos referenciales de gestión educativa, en el nivel primario, Institución Educativa “Divino Corazón de Jesús”. El tipo es básico; el nivel es relacional; el método es hipotético deductivo. Se investigó en una población de 76 niños y niñas del primer al tercer grado, de ambos sexos, matriculados, con muestra censal. La técnica para la variable independiente fue la observación, para la variable dependiente, la revisión documental; los instrumentos, para la variable independiente: la Ficha de Observación (Seriación, conservación y clasificación. Concepción etápica piagetiana), para la variable dependiente: Ficha de Revisión Documental. La variable independiente: El desarrollo cognoscitivo piagetiano. La variable dependiente: Los documentos referenciales de gestión educativa. Se concluye que, existe una relación negativa moderada entre el Desarrollo Cognoscitivo Piagetiano y los Documentos Referenciales de Gestión Educativa en el nivel primario, Institución Educativa “Divino Corazón de Jesús”, distrito Paucarpata, región Arequipa, 2017

Service restoration in distribution systems with prioritization of remote controlled switches

Esta dissertação trata do problema de restabelecimento de energia em sistemas de distribuição de grande porte (com milhares de linhas, barras de carga e chaves seccionadoras) em situações de contingência. Este problema consiste basicamente na determinação de chaves seccionadoras que devem ser operadas para permitir a transferência de blocos de carga a fim de re-conectar consumidores fora de serviço atendendo às restrições operacionais do sistema. Diversas metodologias têm sido desenvolvidas para lidar com o problema de restabelecimento de energia. Entretanto, a maioria perde eficiência computacional quando aplicadas em sistemas de distribuição de grande porte e/ou não fazem distinção entre chaves manuais e automáticas (controladas remotamente). Propõe-se uma metodologia para obtenção, em tempo-real, de planos de restabelecimento de energia em sistemas de distribuição de grande porte, que priorize a utilização de chaves seccionadoras controladas remotamente. Priorizar a utilização de chaves controladas remotamente permite a obtenção de planos de restabelecimento mais rápidos de serem implantados. Para lidar com os múltiplos objetivos e restrições do problema de restabelecimento de energia, a metodologia proposta será baseada em Algoritmos Evolutivos Multi-Objetivo, enquanto que a eficiência computacional para possibilitar o tratamento de sistemas de grande porte será proporcionada através da utilização da codificação de dados denominada Representação Nó-Profundidade. Para validar a metodologia proposta realizar-se-ão diversas simulações computacionais no sistema de distribuição real da cidade de São Carlos-SP, e nas suas versões duplicada, quadruplicada e octuplicada, considerando-se a ocorrência tanto de falta única quanto de múltiplas faltas.This thesis focuses on the service restoration problem in large scale distribution systems (distribution systems with thousands of switches and load buses) in contingency situations. This problem consists basically in determining the sectionalizing switches that must be operated in order to reconnect the out of service loads without violating any operational constraints. Several methodologies have been developed to deal with the service restoration problem in distribution systems. However, the majority of them demand high running time when used for large scale distribution systems and/or do not consider the existence of switches that can be remotely operated. It is proposed a methodology for determining, in real time, service restoration plans in large scale distribution systems. In order to determine service plans that can be implemented faster, the methodology will give priority to use remotely controlled switches. To deal with the multiple objectives and constraints of the service restoration problem, the proposed methodology will be based on Multi-objective Evolutionary algorithms. To guarantee computational efficiency to treat large scale distribution systems, the data encoding called Node-Depth Encoding will be used. The real distribution system of the São Carlos-SP city, and its doubled, quadruplicated and octuplicate versions will be used to validate the proposed methodology. It will be simulated cases considering one and multiple faults