Navegando por Palavras-chave "red mud"

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    Assessment of the use of red mud as a catalyst for photodegradation of bisphenol A in wastewater treatment
    (Iwa Publishing, 2016) Busto, Raquel Vieira; Goncalves, Maraisa [UNIFESP]; Gomes Coelho, Lucia Helena
    This study aimed to investigate the use of red mud (RM) - a byproduct of aluminum production, as a photocatalyst, which was characterized physical-chemically and used in the photodegradation of the target compound bisphenol A (BPA). Chemical processing was performed in the RM (acid treatment, chemical reduction and calcination) to verify the most active catalyst. From the results obtained, a complete degradation kinetics of BPA was carried out using a synthetic matrix (BPA in deionized water) and a real matrix (BPA in wastewater) using natural RM/calcined and TiO2 for comparison. The results indicated the potential use of the RM/calcined, which was able to degrade between 88 and 100% of the pollutant in a synthetic sample. Tests on a real effluent sample resulted in degradation rates that ranged from 59 to 100% with chemical oxygen demand reductions of up to 23% using natural RM/calcined in comparison to TiO2. The blank system (irradiation of the solution without the use of a photocatalyst) and the natural RM/calcined one, resulted in reductions of the toxicity in the effluent sample (measured by EC20 using the marine bacteria Vibrio fischeri) of about 12 times, whereas the same treatment using TiO2 resulted in a toxicity reduction of only seven times. Within these results, the RM/calcined showed potential to be used in wastewater treatment in polishing processes.
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    Feasibility of RF Sputtering and PIIID for production of thin films from red mud
    (ABM, ABC, ABPol, 2014-10-01) Antunes, Maria Lúcia Pereira; Cruz, Nilson Cristino Da; Delgado, Adriana De Oliveira; Durrant, Steven Frederick; Bortoleto, José Roberto Ribeiro; Lima, Vivian Faria; Santana, Pericles Lopes; Caseli, Luciano [UNIFESP]; Rangel, Elidiane Cipriano; Universidade Estadual Paulista (UNESP); Universidade Federal de São Carlos; Universidade Federal de São Paulo (UNIFESP)
    During the extraction of aluminum from bauxite, a waste of oxides containing traces of heavy metals in a highly alkaline matrix, called Red Mud (RM), is produced. In this study RM is characterized and the feasibility of using it as a precursor for the production of thin films by Plasma Sputtering and by Plasma Immersion Ion Implantation and Deposition (PIIID) is demonstrated. The chemical structure and composition, surface morphology, topography, and wettability of the films prepared using such methodologies were investigated. The films consist mainly of the elements aluminum, silicon, iron and carbon. Infrared spectroscopic analyses reveal the presence of C=O, C-H2, Fe(OH), Al-O and Si-C functionalities. RF Sputtering produced films with smoother surfaces, whereas PIIID produced granular surface structures. Surface contact angle measurements showed that despite the presence of oxides and hydroxides, the films are hydrophobic, thus exhibiting an interesting link between the physical and thermodynamical properties.