The effects of preparation and some physico-chemical parameters on the properties of styrene catalyst - based on iron(III) oxide.

1983 ◽  
Vol 48 (2) ◽  
pp. 421-438 ◽  
Author(s):  
Milan Pospíšil ◽  
Jiří Spěváček ◽  
Jindřich Kryška

Hydrated iron(III) oxides were obtained by discontinuous precipitation of an iron(II) sulfate solution with aqueous ammonium - saturated with carbon dioxide to different CO2/NH3 ratios. An additional thermal treatment of these oxides, under different conditions, provided genetic sequences of intermediates and their final products - catalysts on a Fe2O3/K2O basis, with different promoters. The catalysts were studied by means of the microstructural; analysis, thermogravimetry, DTA, IR spectroscopy and further tested by the dehydrogenation of ethylbenzene to styrene. It was observed that by changing the CO2/NH3 ratio in the precipitation of the initial solutions one can influence some of the properties, as well as, the morphology and thermal stability of the initial intermediates of the preparation of the catalysts. The above mentioned properties become practically unified with the increasing number of the heat treatment operations, with all the investigated catalysts - with the exception of the catalysts' behaviour during their reduction with hydrogen. The presence of iron oxides in various valency states and the different phase composition of the catalysts during their reduction affect the final activity and selectivity of the catalyst in the reaction under the study.

2012 ◽  
Vol 2 (10) ◽  
pp. 1-3
Author(s):  
Gyaneswar Bhuyan ◽  
◽  
Dr. R. Anandhan Dr. R. Anandhan ◽  
V. kavitha V. kavitha

2007 ◽  
Vol 9 (3) ◽  
pp. 236-246
Author(s):  
P. D. Magesh ◽  
J. Santanakumar ◽  
P. Venkateshwaran ◽  
A. K. Abdul Nazar ◽  
R. Venkatesan ◽  
...  

2018 ◽  
Vol 8 (5) ◽  
pp. 48-50
Author(s):  
N.V. Lakina ◽  
◽  
A.I. Golovko ◽  
V.Yu. Doluda ◽  
V.G. Matveeva ◽  
...  

Author(s):  
SAMUEL BRITO ◽  
RODOLFO SOBRAL ◽  
Luiz Carlos Sacramento ◽  
Marcos Paulo de Souza Junior

2020 ◽  
pp. 6-11
Author(s):  
Anton Kasatkin ◽  
Anna Nigmatullina ◽  
Mikhail Kopytov

The article presents the results of studies of osmolality and pH of 0,9 % sodium chloride of various manufacturers. To obtain data on the pH value, the data used in the passports are used, and the indicators of its osmolality are de- termined using laboratory tests. 0,9 % sodium chloride from different manufacturers has different pH and osmolality. Knowing the actual values of physico-chemical parameters can increase the accuracy of the results of future clinical studies, which compare the pharmacokinetics and pharmacodynamics of modern plasma-substituting solutions and a solution of 0,9 % sodium chloride.


2019 ◽  
Vol 21 (2) ◽  
pp. 437-453
Author(s):  
Elna Lucilia Santos Corrêa ◽  
Karina Suzana Feitosa Pinheiro ◽  
Cláudio José Da Silva de Sousa ◽  
Luiz Jorge Bezerra da Silva Dias

O Brasil apresenta grande disponibilidade de água doce em seus mananciais. Fazendo parte desse recurso encontra-se, o rio Paciência, localizado na Ilha do Maranhão destacado pela sua importância local, principalmente por contribuir com suas águas para recarga dos mananciais subterrâneos, fonte de abastecimento público de vários bairros de São Luís, capital do estado. No entanto, este rio vem sofrendo comprometimento da qualidade de suas águas, consequência do processo de uso e ocupação dos espaços em sua bacia. Destacando-se como um dos principais problemas relacionados a qualidade de ambientes fluviais,  a eutrofização, que consiste no processo em que o corpo d’água adquire elevados níveis de nutrientes (fosfatos e nitratos), é um indicador determinante da qualidade da água. Neste sentido, o objetivo deste trabalho foi caracterizar a qualidade da água e do estado trófico na bacia hidrográfica do rio Paciência atráves dos parâmetros fisico-químico evidenciando os trechos mais comprometidos conforme os valores alcançados nas análises. Os resultados das análises foram comparados com a CONAMA No. 357/05 que indicaram uma situação preocupante quanto à qualidade da água no local de estudo.Palavras-chave: Qualidade de água; Eutrofização; Ilha do Maranhão. ABSTRACTThe Brazil has great availability of fresh water in its springs. Within these contexts, the Paciência River, located on the Island of Maranhão stands out for its local importance, mainly for contributing its waters to the recharge of the underground springs, source of public supply of several districts of São Luís, capital of the state. However, this river has been compromising the quality of its waters, a consequence of the process of use and occupation of the spaces in its basin. Highlighting as one of the main problems related to the quality of fluvial environments, eutrophication, which consists of the process in which the body of water acquires high levels of nutrients (phosphates and nitrates), is a determinant indicator of water quality. In this sense, the objective of this work was to characterize the water quality and trophic status in the Paciência river basin through the physico-chemical parameters, showing the most compromised stretches according to the values reached in the analyzes. The results of the analyzes were compared with CONAMA No. 357/05 which indicated a worrying situation regarding the quality of the water at the place of study.Keywords: Water quality; Eutrophication; Island of Maranhão. RESUMENBrasil tiene gran disponibilidad de agua dulce en sus manantiales. Parte de este recurso es el río Paciencia, ubicado en la isla de Maranhão, que destaca por su importancia local, principalmente porque contribuye con sus aguas a recargar las fuentes subterráneas, fuente de suministro público de varios barrios de São Luís, capital del estado. Sin embargo, este río se ha visto afectado por la calidad de sus aguas, como consecuencia del proceso de uso y ocupación de los espacios en su cuenca. Destacando como uno de los principales problemas relacionados con la calidad de los ambientes fluviales, la eutrofización, que consiste en el proceso en el que el cuerpo de agua adquiere altos niveles de nutrientes (fosfatos y nitratos), es un indicador determinante de la calidad del agua. En este sentido, el objetivo de este trabajo fue caracterizar la calidad del agua y el estado trófico en la cuenca del río Paciência a través de los parámetros fisicoquímicos, mostrando las secciones más comprometidas de acuerdo con los valores alcanzados en los análisis. Los resultados de los análisis se compararon con CONAMA N°. 357/05, que indicó una situación preocupante con respecto a la calidad del agua en el sitio de estudio.Palabras clave: Calidad del agua; Eutrofización, Isla Maranhão.


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