Síntese e caracterização de aluminofosfato impregnado com molibdênio/zinco visando a dessulfurização por adsorção

Discussions about pollution caused by vehicles emission are old and have been developed along the years. The search for cleaner technologies and frequent weather alterations have been inducing industries and government organizations to impose limits much more rigorous to the contaminant content in fuels, which have an direct impact in atmospheric emissions. Nowadays, the quality of fuels, in relation to the sulfur content, is carried out through the process of hydrodesulfurization. Adsorption processes also represent an interesting alternative route to the removal of sulfur content. Both processes are simpler and operate to atmospheric temperatures and pressures. This work studies the synthesis and characterization of aluminophosphate impregnate with zinc, molybdenum or both, and its application in the sulfur removal from the gasoline through the adsorption process, using a pattern gasoline containing isooctane and thiophene. The adsorbents were characterized by x-ray diffraction, differential thermal analysis (DTG), x-ray fluorescence and scanning electron microscopy (SEM). The specific area, volume and pore diameter were determined by BET (Brunauer- Emmet-Teller) and the t-plot method. The sulfur was quantified by elementary analysis using ANTEK 9000 NS. The adsorption process was evaluated as function of the temperature variation and initial sulfur content through the adsorption isotherm and its thermodynamic parameters. The parameters of entropy (ΔS), enthalpy variation (ΔH) and free Gibbs energy (ΔG) were calculated through the graph ln(Kd) versus 1/T. Langmuir, Freundlich and Langmuir-Freundlich models were adjusted to the experimental data, and the last one had presented better results. The thermodynamic tests were accomplished in different temperatures, such as 30, 40 and 50ºC, where it was concluded the adsorption process is spontaneous and exothermic. The kinetic of adsorption was studied by 24 h and it showed that the capability adsorption to the adsorbents studied respect the following order: MoZnPO > MoPO > ZnPO > AlPO. The maximum adsorption capacity was 4.91 mg/g for MoZnPO with an adsorption efficiency of 49%.

Análise do processo de avaliação de desempenho ambiental face às diretrizes da ISO 14031: um estudo de caso

The present dissertation aims to analyze the evaluation process of environmental performance inside an organization from the building construction section of civil construction based on the NBR ISO 14031 guidelines, which provide orientation regarding the implementation of this project towards the internal organizational management. The theoretical research has addressed concepts and historical development of environmental management inside organizations, from the emergence of the first models to the strengthening of environmental management through the standardization of the Environmental Management System caused by the publication of ISO 14001. It has also addressed the evaluation of environmental performance, the NBR ISO 14031 (concepts, types of indicators of evaluation of environmental performance, the elaboration process of such indicators, as well as its use and evaluation by the high administration). The research has an applied character, with exploratory and descriptive goals, and a qualitative approach based on case study. The data collection will be made through questionnaires, interviews, and documental analysis. Through the present research project, one expects to learn the elements taken into consideration by the organization for the elaboration and selection of indicators; to identify which interested parties contribute in the aforementioned process; to discover which sources are taken into consideration by the organization while establishing its environmental performance goals; to learn how the different kinds of environmental indicators are handled by organizations on daily basis, considering the existence of interferences on the decision making process, whether or not the interested parties are integrated, and if there is an periodical evaluation of environmental performance and how it is handled. One also expects to identify the opportunities for improvement regarding the organization that is object of study.