Membranas híbridas de poliamida/zinco para o tratamento de efluentes com corantes

Abstract

Industrial processes use large volumes of water, thus contributing to the pollution of water resources. In this context, the textile industry has been standing out due to its high degree of pollution, mainly because of the use of pigments. In recent years, modern technologies have been developed for the treatment of these effluents, such as the membrane separation process (MSP), which aims to bring the effluent into compliance with discharge standards. Membranes were prepared using the phase inversion technique from waste synthetic PA66 fiber from the automotive industry, containing zinc (Zn) in proportions of 1, 3, and 5% by weight, with the introduction of magnesium chloride (MgCl2) as a pore-forming agent. Membrane films were evaluated through rheological and morphological characterization techniques, as well as flow measurements. Factorial design was used to assess the influence of membrane factors, effluent concentration, and pressure. Characterization results indicated that the addition of Zn particles favored the formation of more pores, allowing for a greater amount of empty spaces that aid in water absorption, thereby increasing the porosity of the membranes. Based on the analysis of average pore radius, maximum pore radius, water flow, and permeate, the membrane containing 3% by weight of zinc showed lower results compared to the other membranes, likely due to Zn agglomerations. On the other hand, the membrane containing 5% by weight of zinc showed results above 90% in selectivity and color removal, and it had the highest permeate and water flow. Membranes were successfully obtained from waste synthetic polyamide 66 fibers, and the introduction of the inorganic load Zn altered the microstructure of the hybrid membranes compared to the polymeric membrane, achieving results above 90% in color removal from the effluent for both pure PA66 and its hybrids. Statistical analysis (ANOVA) indicated that the type of membrane was significant for flow, final color concentration, and pH, with the membrane containing 5% by weight of zinc being promising, as it offers a cost-effective solution for reducing energy consumption and achieving high color removal.