SciELO - Scientific Electronic Library Online

 
vol.80 número2Anthelmintic acetogenin from Annona squamosa L. SeedsHerpetofauna of an Atlantic rainforest area (Morro São João) in Rio de Janeiro State, Brazil índice de autoresíndice de assuntospesquisa de artigos
Home Pagelista alfabética de periódicos  

Serviços Personalizados

Journal

Artigo

Indicadores

Links relacionados

Compartilhar


Anais da Academia Brasileira de Ciências

versão impressa ISSN 0001-3765versão On-line ISSN 1678-2690

Resumo

MARTINS, Cláudia R. et al. Influence of NO2 and metal ions on oxidation of aqueous-phase S(IV) in atmospheric concentrations. An. Acad. Bras. Ciênc. [online]. 2008, vol.80, n.2, pp.279-290. ISSN 0001-3765.  http://dx.doi.org/10.1590/S0001-37652008000200006.

An investigation was made of the influence of atmospheric concentrations (15 or 130 ppbv) of NO2 on the aqueous-phase oxidation rate of S(IV) in the presence and absence of Fe(III), Mn(II) and Cr(VI) metal ions under controlled experimental conditions (pH, T, concentration of reactants, etc.). The reaction rate in the presence of the NO2 flow was slower than the reaction rate using only clean air with an initial S(IV) concentration of 10-4 mol/L. NO2 appears to react with S(IV), producing a kind of inhibitor that slows down the reaction. Conversely, tenfold lower concentrations of S(IV) ([S(IV)]º = 10-5 mol/L) caused a faster reaction in the presence of NO2 than the reaction using purified air. Under these conditions, therefore, the equilibrium shifts to sulfate formation. With the addition of Fe(III), Mn(II) or Cr(VI) in the presence of a NO2 flow, the reaction occurred faster under all the conditions in which S(IV) oxidation was investigated.

Palavras-chave : aqueous S(IV) oxidation; metal ions; NO2; acid rain formation.

        · resumo em Português     · texto em Inglês     · Inglês ( pdf )

 

Creative Commons License Todo o conteúdo deste periódico, exceto onde está identificado, está licenciado sob uma Licença Creative Commons