离子液体改性花生壳对铬离子的吸附行为与机制

Adsorption Isotherm and Kinetic of Peanut Shells Modified by Ionic Liquid for Cr(Ⅵ)

研究了用离子液体改性花生壳,并考察了改性花生壳对Cr(Ⅵ)的吸附行为与机制。结果表明:在改性花生壳用量10 g/L、温度50℃、初始Cr(Ⅵ)质量浓度10 mg/L条件下,改性花生壳对Cr(Ⅵ)的吸附率达99.82%;吸附过程符合Langmuir等温吸附模型,为单分子层吸附,吸附发生在均匀的吸附点位上,理论最大吸附量q_(m)=9.70 mg/g;R_(L)=0.221<1,表明吸附过程为优惠吸附;吸附过程符合准二级动力学模型,动力学常数k_(2)=0.0452 g/(mg·min),理论平衡吸附量q_(e)=1.14 mg/L,表明吸附过程主要为化学吸附。

The modification of peanut shell by ionic liquid was studied,and the adsorption behavior and mechanism of the modified peanut shell for Cr(Ⅵ)were researched.The results show that under the conditions of peanut shell dosage of 10 g/L,50℃and Cr(Ⅵ)initial mass concentration of 10 mg/L,the adsorption rate is up to 99.82%.The adsorption process fittes well with Langmuir isotherm model which indicates the adsorption is monolayer and take place at specific homogeneous sites.The maximum adsorption capacity is 9.70 mg/g,R_(L)=0.221<1,which indicates the adsorption is favorable.The adsorption kinetics is well expressed by pseudo-second order model with k_(2)=0.0452 g/(mg·min)and q_(e,cal)=1.14 mg/L,which indicate the adsorption process is controlled by chemical adsorption.