活性炭吸附水中铅离子的动态研究

STUDY OF ADSORPTION OF Pb ION ON ACTIVATED CARBON BY UNSTEADY-STATE METHOD

本文采用两种煤质活性炭,研究了其对不同浓度二价铅离于溶液的吸附,应用固定床吸附动力学模型,Marquadt方法非线性回归固定床吸附流出曲线,获得了铅离子在活性炭上的扩散传质系数.结果发现,孔扩散系数D_P强烈地依赖于铅离子入口浓度,随着入口浓度的升高,孔扩散系数变小.随后用上述扩散系数理论预测了其它操作条件下的流出曲线,结果表明实验曲线与理论预测曲线能很好地相符,动态法能可靠地获取液固吸附过程的吸附及扩散系数,为吸附工程设计提供有益的帮助.

The adsorption of Pb (II) on two kinds of activated carbon made from coal was studied. By using the adsorption dynamic model of fixed-bed, the adsorption equilibrium constants and diffusion coefficient of Pb ion were obtained by regression of the data of effluent curves. The results show that the pore diffusion coefficient depends on the concentration of Pb ion. It increases with the increasing of input concentration. The Freund-lich isotherms and mass transfer coefficients obtained were used to predict the theoretical breakthrough curves under other operation conditions. The results showed that the predicted breakthrough curves agree well with the experimental ones.