稀土金属-铝复合金属氧化物对As(Ⅴ)的吸附

As(Ⅴ) adsorption by the composite oxide of rare earth-aluminum

本文以介孔氧化铝为载体、稀土金属的硝酸盐为原料制备了稀土金属-铝复合金属氧化物,通过N2吸脱附等温线对所得稀土金属-铝复合金属氧化物的结构进行表征分析,采用静态吸附实验对所得复合金属氧化物对As(Ⅴ)的吸附性能进行了研究,并就最优吸附剂对As(Ⅴ)的等温吸附和吸附动力学进行了考察.结果表明,嫁接稀土金属之后所得复合金属氧化物仍然保有原来的介孔结构;Y-Al复合氧化物对As(Ⅴ)的吸附性能优于Eu-Al、Pr-Al和Sm-Al复合金属氧化物;最佳Y/MA质量比为1∶10;实验数据经吸附等温式分析发现,Y-Al复合氧化物对As(Ⅴ)的最大吸附容量为62.2 mg·g^-1;根据吸附动力学方程分析发现,Y-Al复合氧化物对As(Ⅴ)的吸附行为遵从准二级动力学方程,因此吸附过程中"表面反应"是主要速率控制步骤.

In this study,rare earth-aluminum composite was synthesized by employing mesoporous alumina and rare earth nitrate as the carrier and rare earth source,respectively.The obtained material was characterized by N2 adsorption-desorption isotherm,and the performance of As(Ⅴ) adsorption over was composite materials were investigated by batch experiments,including adsorption isotherms and kinetics.It was found that the mesoporous structure of alumina was kept well after incorporating rare earth.And As(Ⅴ) adsorption performance of Y-Al composite was better than that of Eu-Al composite,Pr-Al composite and Sm-Al composite.The optimal mass ratio of Y/MA is 1∶10.Additionally,the adsorption data of Y-Al composite were fitted well by Langmuir model,and the maximum As(Ⅴ) adsorption capacity was 62.2 mg·g^-1.The adsorption kinetics were obeyed by pseudo-second-order model,which indicated that "surface reaction" was the limiting step.