TCC - Engenharia de Materiais (UACSA)
URI permanente para esta coleçãohttps://arandu.ufrpe.br/handle/123456789/2914
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Item Adsorção de corantes em materiais híbridos obtidos de biomassa pirolisada com nanopartículas magnéticas(2021-03-05) Nascimento, Rizia Keila do; Araújo, Ana Cláudia Vaz de; http://lattes.cnpq.br/6861890992609511; http://lattes.cnpq.br/8972131109377770The adsorption of residues in aqueous medium is an effective process for treating effluents from the textile industry. Several materials have been developed for this purpose, and their adsorptive capacity has been thoroughly studied. In this work, a new adsorbent material was synthesized by a hydrothermal route. This hybrid material (named HB) is formed by biomass residue (sugarcane straw) and magnetite nanoparticles (NPs), an iron oxide. The magnetite cubic phase in HB was identified by X-ray diffraction. The Fe-O vibrational band, characteristic of iron oxide, was observed by infrared spectroscopy. HB presented a globular morphology, with a wide range of size (between 500 nm and 2 m). The performance of HB as an adsorbent was evaluated through the adsorption of the dyes Congo Red (VC) and Indigo Carmine (IC). The concentrations studied varied between 6.97 and 69.67 mg.L-1 for VC and between 4.66 and 46.64 mg.L-1 for IC. The adsorption kinetics curves showed that the saturation time of HB for both dyes was around 120 h. Most of the adsorption (around 71 % for the VC and 28 % for the IC) occurred in the first 24 h of contact between the adsorbent and the dyes. This indicates the feasibility of using HB on an industrial scale, mainly in the treatment of water contaminated by VC residues. The adsorption kinetics for both systems followed the Pseudo Second Order model, with 99% correlation for VC, and 82% for IC. For the adsorption isotherms, the Langmuir, Freundlich and Temkin models satisfactorily described the HB/VC system (above 95 % correlation) and the Freundlich and Temkin models described HB/IC (above 92 % correlation). The results presented show that HB has potential for adsorption of dyes in aqueous medium.Item Síntese e caracterização de um material nanoestruturado magnético, para adsorção de resíduos de corantes em meio líquido(2022-10-06) Alencar, Ellen Oliveira de Assis; Araújo, Ana Cláudia Vaz de; http://lattes.cnpq.br/6861890992609511; http://lattes.cnpq.br/0326211164564344Pernambuco's agreste region has developed with the growth of the local textile industry, this growth has brought with it the pollution of some rivers in the region. One of the steps in the fabric manufacturing process is dyeing, which uses synthetic dyes with high stability and resistance to degradation. In the fabric washing process, excess dye is released from the fibers and generates contaminated effluents. As a result, many studies have been developed aiming at new efficient methodologies for the decontamination of these effluents. Adsorption has been widely used in the treatment of textile effluents with the use of magnetic nanomaterials that work as adsorbents for textile dyes and are easily removed from the medium, through the application of an external magnetic field. In this work, iron oxide magnetic nanoparticles (NPs) with average crystallite size between 30 and 35 nm were synthesized. These NPs were used as adsorbents for Reactive Black 5 (RB5) dye residues in aqueous medium. The decolorization and removal efficiencies of RB5 by the NPs were around 100% and 40%, respectively. The adsorption kinetics was better adjusted to the Pseudo Second Order method with correlation coefficient R2 = 0,95. For the adsorption isotherms, the Langmuir and Freundlich models were satisfactorily adjusted to the results obtained.Item Síntese e caracterização de um nanocompósito de grafite magnético para adsorção dos corantes Reactive Black 5 (RB5) e Azul de Metileno (AM)(2019-12-13) Damasceno, Bárbara Souza; Araújo, Ana Cláudia Vaz de; http://lattes.cnpq.br/6861890992609511; http://lattes.cnpq.br/6533105269743189Magnetic graphite nanocomposite (NGM) based on magnetic nanoparticles (NPs) and graphite nanoplatelets has been synthesized by a novel hydrothermal synthesis route. NGM and its precursors were characterized by X-ray diffraction (XRD) and infrared spectroscopy (FTIR). The nanomaterial discoloration efficiency (%Ads) using reactive black 5 (RB5) and methylene blue (AM) textile dyes in aqueous solution as target pollutant were evaluated. The influence of adsorptive parameters on effluent discoloration efficiency responses was evaluated from a 23 factorial design and the response surface analysis of central rotational composite design. Adsorption parameters evaluated include: adsorbent mass, adsorbate concentration and agitation speed. It was observed that the parameters agitation speed (rpm) and concentration of adsorbate (mg L-1) are the factors more significant than any other combination and it is highly indicated that they should be parameterized in combination. NGM statistical results showed %Ads ~98% in the RB5 removal, extremely high adsorption velocity, since it reached the adsorption equilibrium within 10 minutes of contact with the adsorbate and it presented 99% adjustment for pseudo first and second order kinetics, besides it presented a maximum adsorptive capacity of ~93 mg g-1 for the adjustment of Langmuir model, predominant in this system. The %Ads of AM onto NPs and graphite was ~59% and 100%, respectively. The study shows that NGM can be magnetically separated from the aqueous solution without introduce any byproduct during adsorption and presented favorable adsorptive properties, which makes evident its applicability of use as environmental remediator. The application of this synthetic rout becomes of technological interest when, besides being unprecedented and low cost, NGM adsorptive properties are attractive to effectively discolor wastewater.