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Polyethersulfone (PES) hollow fiber membranes were produced, containing 3% of two types of clay (Brasgel PA-MMT and Cloisite NA-CLNa), in order to modify the characteristics of the polyethersulfone membrane. By means of the X-ray diffraction, it was possible to observe an exfoliated and/or partially exfoliated structure in the membranes containing clay. From the analysis of contact angle, it was possible to notice an increase in the hydrophilicity of the membrane with the introduction of the clay. Through scanning electron microscopy (SEM), the morphology of the porous support of the membrane was modified with addition of clay, favoring greater uniformity of the pores and fingers. In the flow measurements with distilled water, the membranes with clay obtained the highest flows, being the greater flow with the Cloisite Na clay (~22 L/h.m 2) and was in agreement with the contact angle results. In the analysis of permeation with the oily emulsion, the membrane with Brasgel PA clay in its structure presented the greatest flow (~16 L/h.m 2) and the membrane with Cloisite Na presented the greatest yield (78.28%). Therefore, the clay acted by modifying both the morphology and the hydrophilicity of the polyethersulfone membrane, improving flow and yield.

Membranes have been widely used in the treatment of industrial effluents. However, there are still some limitations in the separation and permeability with respect to these effluents. Therefore, this study investigated the addition of 1% and 5% of an inorganic filler (clay) in polyethersulfone polymer membranes. By contact angle analysis, it was observed that the clay influenced the hydrophilicity of the membrane. The presence of the clay had an important role in the morphology of the membrane, modifying and favoring a greater quantity of pores and macropores for the porous support. For the tensile test, it was seen that the high clay content decreased the membranes properties. The flow tests, having a flow stabilized around 300 L/h·m 2 for membranes containing clay, evidenced the efficiency of the membrane for the treatment of indigo blue, representing a 200% increase in relation to polyethersulfone membrane. The membrane containing 1% of clay presented the highest level of rejection to the effluent, around 94.0%. Thus, it was evident that the addition of montmorillonite clay modified the membrane structure contributing to a higher selectivity and permeability.

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The membrane separation process has been significantly highlighted for the treatment of water and effluents in a scenario of water resource scarcity. Effective treatments capable of reducing costs and waste are always necessary, with the planning of the experiments before their execution of interest. The purpose of this work was to evaluate, through experimental planning, the influence of the polyethersulfone (PES), polyvinylpyrrolidone (PVP), and clay variables on the membranes’ parameters (viscosity and contact angle), seeking the best compositions for the production of hollow fiber membranes. Membranes were produced according to the compositions proposed by the planning and were characterized by Viscosity, Contact Angle, X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), and flow measurements. Through XRD, it was shown that the characteristic peaks of the clay remained in the membranes with higher concentrations. SEM analysis showed the influence of clay on the membranes’ porosity as well as the relation between “fingers” formation and PVP. From the flow measurement test, the relation between the obtained flow and the polymer and clay contents was verified. These tests showed the significant influence of clay on the membranes’ performance. Thus, the use of experimental planning resulted in the development of membranes and their importance in the design of future studies, making it possible to predict and simulate experiments.

Motivado pelas necessidades tecnológicas e ambientais, os processos de separação por membranas têm exibido uma grande melhora em relação às técnicas tradicionais. Estes benefícios incentivam a aplicação de separações por membranas e estimulam o desenvolvimento em processos de purificação e esterilização nas indústrias farmacêutica e alimentícia, em geral. Além disso, elas são utilizadas no tratamento de água para uso industrial ou urbano, dessalinização, separação de gases, clarificação de sucos, hemodiálise e no tratamento de efluentes. Esta última, é a aplicação que este trabalho se destina, especialmente na separação de água dos corantes têxteis, isto é, o índigo blue. Dessa forma, foram sintetizadas membranas de polisulfona na forma de fibra oca, com teores variados de alumina, para uso no tratamento de efluentes. Foram avaliadas as características morfológicas, a hidrofilicidade, as medidas de fluxo e a medida de turbidez delas. As membranas foram produzidas pelo método da inversão de fase, via extrusão a frio, imersão - precipitação. Os resultados obtidos por filtração indicam que as partículas de alumina podem aumentar o fluxo de água melhorando a hidrofilicidade da membrana. Por MEV, foi verificada uma maior quantidade de poros, de tamanhos menores, com a inserção da alumina na polisulfona. Desse modo, por meio da análise do Turbidímetro, a quantidade de partículas suspensas de índigo blue na membrana com alumina foi menor, visto que os poros destas são menores e em maior quantidade, gerando uma maior remoção do corante. Assim, com o aumento do teor de alumina, foi melhorada a separação entre a água e o corante índigo blue.

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In order to reduce the impacts of the industrial effluent on the environment, silicon carbide hollow fiber membranes were prepared by the precipitation-immersion technique and sintered at 1450 and 1500 °C. The membranes were characterized by X-ray diffraction, their surface structure was characterized by scanning electron microscopy and atomic force microscopy, pore size distribution and porosity, mechanical properties, and flow measurements with distilled water and effluent generated by the indigo blue industry. The sintered membranes presented crystalline phases of silicon carbide and aluminum oxide. The tubes presented defect-free microstructure and uniform porous surface, with porosity above 50%. The silicon carbide membrane presented significant reductions of the solutes and colloidal particle contents in the effluent. The membranes sintered at 1500 °C proved to be more efficient for reductions of the turbidity and color of the effluent. Silicon carbide hollow fiber membrane is an interesting alternative for the treatment of effluents from the textile industry.