Adsorção e dessorção de arsênio por hidróxidos duplos lamelares e seu emprego na remoção deste elemento de águas

• Ano de defesa: 2011
• Autor(a) principal: Rosa, Guilherme Fiurin
• Orientador(a): Bellato, Carlos Roberto
• Banca de defesa: Suarez, Willian Toito , Mello, Jaime Wilson Vargas de
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Mestrado em Agroquímica
• Departamento: Agroquímica analítica; Agroquímica inorgânica e Físico-química; Agroquímica orgânica
• País: BR
• Palavras-chave em Português: Hidróxidos duplos lamelares; Arseniato; Adsorção; Águas
• Palavras-chave em Inglês: Layered Double Hydroxides; Arsenate; Adsorption; Water
• Área do conhecimento CNPq: CNPQ::CIENCIAS EXATAS E DA TERRA::QUIMICA::QUIMICA ANALITICA
• Link de acesso: http://locus.ufv.br/handle/123456789/2102

This paper addresses at first the problem of the organisms contamination effect and consequences by arsenic. It also deals with the anionic clays synthesis and characterization of the layered double hydroxides (LDH) type, the best clay choice, and their application for the arsenate removal (As (V)) from contaminated waters. Arsenic is a naturally occurring element, belonging to non metal group of the periodic table. Its content in igneous and sedimentary rocks varies from 0.5 to 2.5 mg kg-1. In sedimentary rocks, it may appear coprecipitate with iron hydroxides or sulfides. Arsenic is present in more than 245 minerals, most of sulfides associated with metals such as Au, Co, Cu, Fe, Ni and Pb. Its mobility in the environment occurs due to various factors. The water contamination by it can be associated with mining activity. Considering the toxicological problems generated by it, the World Health Organization (WHO) has recommended values below 10 mg L-1 for drinking water, whose reference value is followed by the regulatory agencies in Brazil. From this context, this work offers a safe, efficient and environmentally feasible method for the water decontamination from arsenic. This experiment consists of two adsorption methods, being one static and another one dynamic using the synthetic clays. In the first method, we obtained the adsorption values up to 96%, using synthetic materials and natural waters with a 2000 μg L-1 concentration. In the dynamic experiments, we obtained an adsorption capacity of 153.39 mg g-1 to 470.59 mg g-1, according to the adsorbent mass variation and the riverbed flow. It was observed a complete adsorbent material desorption that can be reused for many adsorption/desorption several cycles. Besides the arsenic adsorption efficiency by Layered Double Hydroxides proven through the experiments, the process shows the social and environmental evidence importance, because the population health improvement and the waste low generation by contaminant immobilization in the solid phase and its pre-merger when he desorption was performed.