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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/8972131109377770
The 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.
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/8972131109377770
The 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.