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

Química Nova

Jardim, Wilson F.¹  Rocha, Júlio César¹  Miretzky, Patricia¹  Bisinoti, Márcia Cristina¹  Universidad de Buenos Aires, Buenos Aires, Argentina¹  Universidade Estadual Paulista, Araraquara, Brasil¹  Universidade Estadual de Campinas, Campinas, Brasil¹ 

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) adsorption studies in top soils (top 10 cm) from the Rio Negro basin show this process depends strongly on some selected parameters of the aqueous phase in contact with 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 solution resulted in a lower adsorption of Hg (II) at pH 5.0. Soils with higher organic matter content were less affected by changes in the salinity. An increase in the initial Hg (II) concentration increased the amount of Hg (II) adsorbed by the soil and decreased the time needed to reach equilibrium. A Freundlich isotherm provided 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 fast and followed pseudo-second order kinetics. An environmental implication of these results 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】

Unknown