Navegando por Autor "Barros Neto, Eduardo Lins"

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Chromium extraction by microemulsions in two- and three-phase systems
(Associação Brasileira de Engenharia Química, 2015) Melo, Keila Rejane de Oliveira; Dantas, Tereza Neuma de Castro; Moura, Maria Carlenise Paiva de Alencar; Dantas Neto, Afonso Avelino; Oliveira, Mônica Rodrigues; Barros Neto, Eduardo Lins
Microemulsion systems were used to remove chromium from an aqueous solution obtained from acid digestion of tannery sludge. The systems were composed by: coconut oil soap as surfactant, 1-butanol as cosurfactant, kerosene as the oil phase, and chromium solution as the aqueous phase. Two- and three-phase microemulsion extraction methods were investigated in the experiments. Viscosity, effective diameter of the droplets, and extraction and re-extraction efficiencies were evaluated for each system. Two- and three-phase systems showed small variations in droplet diameter, which can be attributed to the formation of micellar structures. Chromium recovery efficiencies for the studied systems were over 96%. The re-extraction step showed that the stripping solution used can release more than 96% of the chromium from the microemulsion phase. Experimental results confirm that chromium can be recovered efficiently using microemulsion systems
Development of asphalt emulsions incorporating waste lubricating oil
(Associação Brasileira de Petróleo e Gás, 2015) Brito, P. K. S.; Carvalho, D. F.; Moura, M. C. P. A.; Barros Neto, Eduardo Lins; Dantas, Tereza Neuma de Castro; Dantas Neto, Afonso Avelino
The aim of this study is to develop asphalt emulsions incorporating used lubricating oil (OLUC), as a modifier agent, to produce stable emulsions and resulting in cost-effective and environmentally friendly product suitable for paving applications. A central composite design (CCD) is proposed to reduce the experiment’s number. The asphalt emulsions were characterized by Saybolt Furol viscosity, residue by evaporation, settlement and storage stability, sieve test, ductility, and penetration over residue. The results showed that asphalt emulsions, in accordance with all technical specifications, can be produced at 80°C, using 5 minutes as emulsification time and low amounts of surfactant. Moreover, the experiment incorporated OLUC in the composition of asphalt emulsions to obtain new low-cost products for use in paving operations
Investigation of gas-liquid equilibrium of a surfactantbased desiccant liquid developed for natural gas dehydration
(Associação Brasileira de Pesquisa e Desenvolvimento em Petróleo e Gás, 2008) Nóbrega, Geraldine Angelica Silva da; Moura, Maria Carlenise Paiva de Alencar; Barros Neto, Eduardo Lins; Chiavone Filho, Osvaldo; Dantas Neto, Afonso Avelino
Natural gas is an important source of primary energy that, under normal production conditions, is saturated with water vapor. Water vapor increases the corrosiveness of natural gas, especially when acid gases are present. Several methods can be used to dry natural gas. The objectives of this study were to develop a procedure to absorb the water from natural gas in a new surfactant-based desiccant liquid and to evaluate gas-liquid equilibrium data. The principle of the desiccant liquid preparation is based on microemulsion formation (water-surfactant-oil mixtures). The dynamic method was applied for the determination of the equilibrium data, based on the saturation of the phases. The equilibrium criterion was the constancy in water concentration. Three surfactants were used for the natural gas water removal. The experimental results indicated the feasibility of the water removal from the natural gas using a specially designed absorption column and a desiccant liquid prepared with turpentine and surfactant. The gas-liquid equilibrium data were also calculated by the Peng-Robinson equation of state with the van der Waals and the modified Huron-Vidal mixing rules
Molecular behavior of ionic and nonionic surfactants in saline medium
(ELSEVIER, 2009) Santos, Francisco Klebson Gomes dos; Barros Neto, Eduardo Lins; Moura, Maria Carlenise Paiva de Alencar; Dantas, Tereza Neuma de Castro; Dantas Neto, Afonso Avelino
The aim of this study was to investigate the molecular behavior of ionic and nonionic surfactants at differ ent salt concentrations. The nonionic surfactants used in this work were nonylphenol 20 EO, nonylphenol 100 EO, lauryl alcohol 10 EO, and lauryl alcohol 23 EO, being EO the number of ethene oxide groups. The ionic surfactants were synthesized through saponification reactions using the following vegetable oils: coconut oil and castor oil. The cmc (critical micelle concentration) of each surfactant was determined using surface tension measurements at different surfactant and salt concentrations. The study of surfac tant adsorption, using the Gibbs equation with factor n = 1 for nonionic surfactants and n = 2 for ionic ones, allowed to obtain the packing area per surfactant molecule, the surface excess, and the Gibbs free energy of micellization. The obtained results were compared and discussed in view of the hole of the type of surfactant and electrolyte influence. From the obtained results, it can be concluded that the ionic surfactants, due to electrostatic repulsion between ionic head groups, showed higher cmc values than those obtained for nonionic ones. When salt ions were added to the ionic surfactant solution, the cmc values were decreased due to the existence of electrostatic interactions between the ionic head groups of these molecules with the electrolytes. For nonionic surfactants, the increasing ethoxylation degree, the hydrophilic portion of surfactant molecule, and electrolyte addition diminishes cmc values. Concerning to the Gibbs free energy of micellization, the obtained results showed that the adsorption process was spontaneous for all studied surfactants, but it was thermodynamically more favorable for nonionic ones
Remoção de corante têxtil utilizando a casca do abacaxi como adsorvente natura
(Instituto Federal de Educacao, Ciencia e Tecnologia do Rio Grande do Norte (IFRN), 2018-08-30) Antunes, Evelyn Cristine Evangelista da Silva; Pereira, Jéssyca Emanuella Saraiva; Ferreira, Ruan Landolfo da Silva; Medeiros, Maria de Fátima Dantas de; Barros Neto, Eduardo Lins
Este trabalho avaliou a utilização da casca de abacaxi (Ananas comosus) como adsorvente para remoção do corante catiônico azul de metileno presente em solução aquosa. O adsorvente foi obtido através da secagem e trituração das cascas da fruta. A granulometria do material foi < 0.2 mm. Os ensaios de adsorção foram realizados em batelada, sob rotação de 150 rpm e à temperatura de 30 e 40°C. O efeito da quantidade de adsorvente (0,1g-0,5g) e concentração inicial de adsorbato (60ppm-100ppm) no percentual de remoção (%R) e na capacidade de adsorção unitária (qe) foram avaliados. Os modelos de isoterma de Langmuir e Freundlich foram utilizados na descrição matemática do sistema. A casca de abacaxi apresentou remoção de até 81 % do corante azul de metileno. O aumento da massa de adsorvente proporcionou um aumento na percentagem de remoção do corante e diminuição da capacidade de adsorção unitária (qe). O aumento da concentração inicial do adsorbato em solução aquosa provocou uma redução na percentagem de remoção e um aumento na capacidade de adsorção unitária (qe). O modelo de isoterma de Freundlich foi o que melhor se ajustou aos dados experimentais. O ajuste do modelo de Langmuir aos dados experimentais revelou a capacidade de adsorção unitária máxima para a casca de abacaxi como sendo de 17,12 mgg-1 e 10,06 mgg-1 à 30C e 40°C, respectivamente. O caráter da reação de adsorção foi exotérmico pois a elevação da temperatura desfavoreceu a remoção do corante. Os resultados apontam que esse resíduo agroindustrial tem potencial para ser utilizado como um adsorvente econômico para a remoção de azul de metileno
A review on chemical flooding methods applied in enhanced oil recovery
(Associação Brasileira de Pesquisa e Desenvolvimento em Petróleo e Gás, 2008) Gurgel, Alexandre; Moura, Maria Carlenise Paiva de Alencar; Dantas, Tereza Neuma de Castro; Barros Neto, Eduardo Lins; Dantas Neto, Afonso Avelino
In spite of the recent worldwide interest for alternative sources of energy, with especial and strategic interest in fuels derived from renewable products, the situation of petroleum in many countries stills drives much concern. Brazil, for example, is continuously advancing in the discovery of novel oil reservoirs and in the devise of potential ways to exploit oil both onshore and offshore. Many research projects are joining industry and university personnel, aiming to improve the technology to enhance oil productivity. In addition to the primary recovery techniques and several physical methods conceived as enhanced oil recovery (EOR) methods, the development of EOR processes based on operations which involve chemicals is greatly promising, many of which employing surfactants. Knowledge on the interfacial properties between oil, water and solid rock reservoirs, especially under extreme conditions, with occasional presence of natural gas, is important to better implement the EOR method. In view of this, surfactant-based chemical systems have been reported by innumerous academic studies and technological operations throughout the years as potential candidates for EOR activities. In this article, focus is given on recent advances effected by the application of chemical methods in oil recovery

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Navegando por Autor "Barros Neto, Eduardo Lins"