活性炭的Zeta电位对其吸附各种染料规律的影响2．活性炭对阴离子染料酚红的吸附

THE EFFECT OF Zeta POTENTIAL OF ACTIVATED CARBON ON THE ADSORPTION OF DYES FROM AOUEOUS SOLUTION Ⅱ. The Adsorption of Anionic Dye Phenol Red

通过在不同ｐＨ下活性炭吸附阴离子染料酚红规律的研究，发现ｐＨ对活性炭吸附酚红的影响，一方面是ｐＨ不同时活性炭表面ζ电位的带电性不同；另一方面是酚红的溶解度随ｐＨ而变化，这两个因素决定了活性炭对酚红的吸附性能。当ｐＨ小于活性炭的ｐＨ＿ｚｐｃ时活性炭表面ζ电位带正电，随着ｐＨ的降低，ζ电位增加，对阴离子酚红的吸附量随之增大。反之，当ｐＨ大于ｐＨ＿ｚｐｃ时，随着ｐＨ的增大，ζ电位降低以及酚红溶解度的增大，吸附量很快下降直至趋于零。此外还通过活性炭对阴离子染料酚红在不同ｐＨ下的吸附动力学和吸附热大学参数的估算，进一步揭示了活性炭在不同ｐＨ下对酚红的吸附机理。

The effect of Zeta potential of the activated carbon on the adsorption of anionic dye phenol red(PR ) from aqueous solution has been studied. The pH_zpc of the activated carbon has been measured bymicroelectrophoresis method. The saturated amount of PR adsorbed on the activated carbon versus Zetapotential plots has also been determined. The results show that the electrostatic interaction between anion-ic dye and the surface of activated carbon has a great effect on the adsorption capacity and that the adsorp-tion capacity also obviously changes with the solubility of PR. When the pH of the activated carbon suspen-sion is lower than pH_zpc,the Zeta potential of the carbon surface is positive, Therefore,with Zeta potentialincreasing the electrostatic attraction between anionic dye and the carbon surface greptly increases the ad-sorption capacity. However, when the pH of the activated carbon suspension is higher than pH_zpc, the Zetapotential of the carbon surface is negative,the electrostatic repulsion between anionic dye and the carbonsurface is enhanced intensively with Zeta potential decreasing. On the other hand, the solubility of PR in-creases with pH increasing,therefore,the adsorption capacity is gradually reduced and down to vanish. The adsorption kinetic and thermodynamic parameters as functions of pH have been evaluated. Themechanism for adsorption of anionic dye PR on activated carbon has also been studied.