05.1 - Graduação (UACSA)
URI permanente desta comunidadehttps://arandu.ufrpe.br/handle/123456789/2909
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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 Aplicação de nanomateriais advindos de biomassa para tratamento de águas residuárias da indústria têxtil(2019-01-25) Nascimento, Rizia Keila do; Araújo, Ana Cláudia Vaz de; http://lattes.cnpq.br/6861890992609511; http://lattes.cnpq.br/8972131109377770The inadequate disposal of industrial effluents has caused serious problems of environmental contamination worldwide. In the textile pole of Pernambuco some cases of river pollution were reported due to the process of dyeing and washing of fabrics. In this work, the feasibility of the use of nanostructured carbonaceous materials (CN) in the adsorption of textile dyes is studied. To obtain the carbonaceous material sugarcane leaves were used, these were washed, dried, crushed and submitted to hydrothermal synthesis. The samples were characterized by X-ray diffractometry (XRD), infrared (IR) spectroscopy, thermogravimetric analysis (TGA) and porosimetric analysis. The synthesized materials were presented as finely divided dark powders. In adsorption analyzes of the indigo carmine and red congo dyes the nanomaterials showed to be promising adsorbents. It was possible to observe a favorable behavior in relation to the adsorption of the dyes in liquid medium. The Langmuir, Freundlich and Redlich- Peterson isotherm models were suitable for the studied materials. The kinetic adsorption analysis suggests a pseudo second order behavior. The adsorptive mechanism of the nanomaterials could be characterized as heterogeneous, with adsorbate / adsorbent interactions of a chemical nature, where adsorption in monolayers is carried out at low concentrations and in multilayers at high concentrations of dye.Item Produção de nanopartículas magnéticas aplicada ao processo de tratamento de efluentes oriundos das indústrias têxteis(2018-08-27) Damasceno, Bárbara Souza; Araújo, Ana Cláudia Vaz de; http://lattes.cnpq.br/6861890992609511; http://lattes.cnpq.br/6533105269743189Iron oxide magnetic nanoparticles (NPs) were synthetized by chemical coprecipitation method under ultrasound. Synthetized NPs were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, porosimetry and magnetometry. The crystalline phase of the obtained NPs was identified as maghemite and the crystallite average size was estimated by Scherrer equation around 31.5 nm. The FTIR spectra presented distinct absorptions bands at corresponding to intrinsic stretching vibrations of Fe–O bond at the iron oxides. Langmuir and BET surface areas of as-formed samples is 220,15 ± 19,81 m2 g-1 and 127,19 ± 4,94 m2 g-1 respectively. NPs samples present ferromagnetic behavior and saturation magnetization (SM) value of 46 emu g-1. Adsorption performances on synthetized and commercial nanoparticles were investigated and compared. The influences of parameters including pH, dye concentration, and agitation time have been investigated in order to find the optimum adsorption conditions. Parameters as pH 4.0, with 150 min of contact time and dye concentration of 20 mg L-1 were chosen. Adsorption results indicate that the isotherm and kinetics for dye adsorption on NPs obey Freundlich isotherm and pseudo-second-order kinetic, respectively. The maximum dye (20 mg·L-1) removal efficiency to maghemite NPs was found to be 43% and to commercial magnetite NPs was 33%. For the same experimental conditions, maghemite also had better application of the available area for adsorption than the magnetite NPs, presenting values of 8.80 mg g-1 and 6.12 mg g-1, respectively.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.