Adsorção e dessorção de arsênio por quitosana-Fe(III)- reticulada e seu emprego na remoção deste elemento de águas da região do Quadrilátero Ferrífero, MG.

• Autor(a) principal: Oliveira, Cristiane Pereira de
• Data de Publicação: 2008
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/2135
• topic: Quitosana-Fe(III)- reticulada; Adsorção; Arsênio; Quitosana; Chitosan-Fe(III) crosslinked; Adsorption; Arsenic; Chitosan; CNPQ::CIENCIAS EXATAS E DA TERRA::QUIMICA::QUIMICA ANALITICA

Arsenic occurs in nature in a variety of chemical forms, including organic and inorganic species. Waters used for human consumption with arsenic concentrations above the established limits for the environmental control agencies (10,0 μg L-1) are considered dangerous to human health. Among the alternative methods employed for arsenic removal from polluted waters, stands out the method of adsorption by natural materials as chitosan, obtained by alkaline deacetylation of the chitin, one of the most abundant biopolymers in nature. This present work had as objective to evaluate the efficiency of the chitosan-Fe(III)-crosslinking in the adsorption and removal of As(V) of waters of the Iron Quadrangle region, MG. The chitosan samples and the complex chitosan-Fe(III)-R characterization was accomplished by different analyses. The As (V) adsorption in the chitosan-Fe(III)-R studies were carried out with 50,0 mg of adsorbent in 10,00 mL of As(V) solution, with optimum pH of 7,00 and the time of equilibrium of 60 minutes. The maximum As(V) adsorption capacity in chitosan-Fe(III)-R was 39,2 mg g-1 and it was determined by the Langmuir isotherm. The As(V) adsorption capacity in the natural purified chitosan was lower than the one for the chitosan-Fe(III)-R complex, what demonstrates the importance of the chemical modification of chitosan. High concentration of chloride and nitrate anions did not show significant effect in the As(V) removal. The As(V) adsorption was reduced by phosphate ions present in concentrations higher than the As(V) concentration. The desorption was achieved with 1,00 mol L-1 (97,5%) citric acid solution. The As(V) removal process by chitosan-Fe(III)-R was applied to samples of waters of the Iron Quadrangle region, MG, removing up to 99,9% of the pollutant.