Factors affecting Hg (II) adsorption in soils from the Rio Negro basin (Amazon)

Quimica nova

Miretzky, Patricia¹  Rocha, Júlio César²  Jardim, Wilson F.³  Bisinoti, Márcia Cristina³ 

[1] Universidad de Buenos Aires, Buenos Aires, Argentina;Universidade Estadual Paulista, Araraquara, Brasil;Universidade Estadual de Campinas, Campinas, Brasil

关键词: mercury;    soils;    Freundlich isotherm.;   

DOI  :  10.1590/S0100-40422005000300014

学科分类：化学（综合）

来源: Sociedade Brasileira de Quimica

【 摘 要 】

Mercury (II) adsorptionstudies in top soils (top 10 cm) from the Rio Negro basin show this processdepends strongly on some selected parameters of the aqueous phase in contactwith the soils. Maximum adsorption occurred in the pH range 3.0-5.0 (>90%).Dissolved organic matter shows an inhibitory effect on the availability of Hg(II) to be adsorbed by the soils, whereas a higher chloride content of the solutionresulted in a lower adsorption of Hg (II) at pH 5.0. Soils with higher organicmatter content were less affected by changes in the salinity. An increase inthe initial Hg (II) concentration increased the amount of Hg (II) adsorbed bythe soil and decreased the time needed to reach equilibrium. A Freundlich isothermprovided a good model for Hg (II) adsorption in the two types of soil studied.The kinetics of Hg (II) adsorption on Amazonian soils showed to be very fastand followed pseudo-second order kinetics. An environmental implication of theseresults is discussed under the real scenario present in the Negro River basin,where acidic waters are in contact with a soil naturally rich in mercury.

【 授权许可】

CC BY