Adsorção de cádmio e chumbo em solução aquosa por lama vermelha natural e com diferentes ativações

• Autor(a) principal: Silva, Mariana Scicia Gabriel da [UNESP]
• Data de Publicação: 2015
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://hdl.handle.net/11449/132704; http://www.athena.biblioteca.unesp.br/exlibris/bd/cathedra/15-12-2015/000854252.pdf
• topic: Cadmio; Chumbo; Lama vermelha; Adsorção; Cadmium

Some elements are considered toxic, even in low concentrations, causing many public health problems. Among the toxic metals cadmium and lead have highlighted, as they are widely used in industrial activities, can cause contamination of soil and surface water and groundwater. Several alternatives are being studied for the removal of these metals. The aluminum industry generates a by-product known as red mud, formed large-scale requiring large area for your disposal. Studies have been made in order to reduce the amount of waste generated through technologies that will enables their reuse. An alternative is the use of red mud as adsorbent for treating contaminated liquids and waste areas, which when activated by heat and chemical treatment have shown increased adsorption properties. Thus, in the first step of this work red mud samples were activated by heat and chemical treatment, characterized the adsorption isotherms obtained using the Langmuir model and Freundlich. Subsequently, we analyzed the effect of different values of pH and temperature in the adsorption and obtained time balance and adsorption kinetics of the reaction, allowing to quantify the adsorption potential of cadmium and lead. The red mud is a clay material with mesoporous and high alkaline content, and high electrical conductivity. In most cases studied, the samples were best described by the Freundlich model, and the red mud thermally activated 400ºC showed the best adsortpion capacity 0.96 mmol/g Cd2+ and 2.93 mmol/g Pb2+. In all cases, the greater adsorption efficiency occurred at pH around 7, the equilibration time was close to 420 minutes, the reaction kinetics followed best to the pseudo second order model and endothermic reaction occurred