研究了MgAl水滑石(LDH)焙烧产物(LDO)对Cr(Ⅵ)的吸附性能.考察了吸附温度对LDO吸附性能的影响,研究了吸附过程的热力学和动力学行为.结合XRD和FT-IR表征,阐明其吸附机理.结果表明,CrO42-已成功插入水滑石层间,适当提高吸附温度有利于LDO恢复LDH晶相.在20～60℃范围内,随吸附温度升高,LDO对Cr(Ⅵ)吸附量增大,50～60℃时,Cr(Ⅵ)吸附量为91 mg/g.Cr(Ⅵ)的吸附平衡数据符合Langmuir模型方程,△G°为负值说明吸附过程为自发过程,△S°和△H°为正值表明吸附为熵增的吸热过程.吸附动力学符合伪二级动力学模型,LDO的吸附活化能为20.04 kJ/mol,表现为扩散控制的活性化学吸附过程.
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