Adsorção de cobre e chumbo em material particulado

AUTOR(ES)
DATA DE PUBLICAÇÃO

2000

RESUMO

The interactions of copper (II) and lead (II) were investigated on suspended particles (lake sediment) in the absence and presence of humic acid as dissolved organic matter (DOM), where the metal and particulate concentrations, ionic strength, and pH were varied. The reaction time was 24 h at room temperature. The surface site density (Ns) and surface acidity constants (pKa1, pKa2) were estimated by calculating the potentiometric titration data conducted in three ionic strength values. The presence of DOM increased the dissolved metal cencentrations. The model of Langmuir s adsorption isotherm was utilized to treat the data, KL and qmax parameters were estimated. The ion Pb showed higher aflinity than Cu to the solid surface. The "particle concentration effect" has been observed. Increasing ionic strength leads to a decreasing metal adsorption to most of the the suspensions and dissolved organic carbon (DOC) values too. Adsorption increased with increasing pH. Kd values were higher at alkaline pH range and in the absence of DOM. The diffuse layer-surface complexation model (DLM) was used to describe pH-adsorption edges. The adsorption constants were determined by DLM. Metal species weakly adsorbed at pH from neutral to alkaline were dominant.

ASSUNTO(S)

complexos metalicos adsorção acido humico

ACESSO AO ARTIGO

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