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Ref.: MceSi33-001

Production and Characterization of Novel CoAlFe-Layered Double Hydroxide employing bauxite residues from Amazon Region (Brazil)

Apresentador: CASSIO FERNANDES DE ARAUJO

Autores (Instituição): DE ARAUJO, C.F.(INSTITUTO FEDERAL DO PARÁ); CAMPOS, A.D.(UNIVERSIDADE FEDERAL DO PARÁ); DOS SANTOS, G.R.(UNIVERSIDADE FEDERAL DO PARÁ); NASCIMENTO, R.S.(UNIVERSIDADE FEDERAL DO PARÁ); FIGUEIRA, B.A.(INSTITUTO FEDERAL DO PARÁ);

Resumo:
Layered double hydroxide (LDH) are part of an important group of anionic clays with great technological relevance in areas such as biodiesel production, catalysis, slow release of pharmaceuticals and retention/photodegradation of a wide range of persistent organic pollutants. They are usually obtained through synthetic co-precipitation routes using commercial reagents. This work presents a study of the transformation of bauxite tailings from the western region of Pará (Amazon, Brazil) into layered double hydroxide in the Co-Al-Fe system, after acid leaching of the tailings (extraction of Al3+ and Fe3+ ions), with the addition of CoCl2 and NaOH solution up to alkaline pH (co-precipitation method). The influence of the synthesis parameters (time and temperature) on the production of LDH without impurities was investigated. The bauxite residues and LDH have been characterized by elemental analysis, powder X-ray diffraction, FT-IR spectroscopy and scanning electron microscopy. The results indicated that LDH material was successfully synthesized at 100º C for 24 h of hydrothermal treatment with high degree of crystallinity, interlamellar spacing of around 7 Å and average crystal size of 12,6 nm (Scherrer Equation) observed by XRD analysis. Diagnostic FTIR bands of the octahedral layers were identified between 4000-400 cm-1 and platy morphology with an average crystallite size of around 10 micrometers.