【摘要】 采用改变pH值、电解质浓度和各种金属离子插层的方法,调整对蒙脱石胶体的ζ电位,研究了ζ电位变化与吸附金属铬离子性能的关系,并用螯合物调控蒙脱石的ζ电位,探索提高吸附铬离子性能的有效方法.研究结果表明,蒙脱石对铬离子的吸附性与ζ电位有关,随着ζ电位的增大,吸附量明显增大;螯合物改性能使蒙脱石ζ电位发生明显变化,经邻菲罗啉螯合物改性的蒙脱石电性由负变正;对于离子交换吸附,蒙脱石吸附前ζ电位的绝对值必须大于吸附后ζ电位的绝对值,并且吸附前后ζ电位差值越大,越有利于提高对低浓度铬离子的吸附;用邻菲罗啉与铬离子的螯合物调控蒙脱石的ζ电位,能使对铬离子的吸附量增大1倍以上,因此,采用螯合物调控蒙脱石ζ电位的方法有利于提高离子交换吸附的效果.更多还原

【Abstract】 Use of montmorillonite as sorbents to remove toxic heavy metals from aqueous solutions was increa-singly paid attention.In order to improve the soption ability of montmorillonite,various polyoxy cations(Zr4+,Al3+,Si4+,Ti4+),surfasctants(quaternary ammonium cations)and acid activation were widely used to alter the surface properties.In fact,soption ability of montmorillonite depends on electrokinetic behavior of colloid suspension.The values of ζ-potential have a prominent effect on its adsorptive affinity for metal cations.Therefore,the main attempts in this work are focused on ζ-potential of montmorillonite,and the relationships between montmorillonite ζ-potential and adsorption capacity for Cr(Ⅲ).Various chelates were utilized to regulate montmorillonite ζ-potential in order to find a effective method which could improve the adsorption capacity of montmorillonite for Cr(Ⅲ).The results show that the adsorption capacity is ζ-potential-dependent,and increased greatly with its negative value increasing.The ζ-potentials of montmorillonite modified by chelates were changed evidently,and took place reversal from negative to positive after modified by 1,10-phenanthroline chelates.The effect of cation exchange adsorption depended on Absolute values of ζ-potential,which before adsorption must be higher than that after adsorption.It was also found that modified montmorillonite showed higher adsorption capacity with more difference values of ∣[KG-1/6]ζ[KG-2]∣-potential between before and after adsorption.The adsorption quantity of Cr(Ⅲ)on montmorillonite could be double when ζ-potential was regulated by 1,10-phenanthroline chelates.Therefore,the cation exchange adsorption capacity of montmorillonite,whichζ-potential regulated by chelates,could be improved greatly.更多还原