改性高炉渣对染料的吸附动力学及热力学研究

Adsorption kinetics and thermodynamics of dyes on modified blast furnace slag

以高炉渣和壳聚糖为原料,制备了高温改性高炉渣-壳聚糖复合吸附剂(TBFSC)和盐酸改性高炉渣-壳聚糖复合吸附剂(ABFSC),考察了2种吸附剂对酸性蒽醌蓝和活性艳红K-2BP的吸附性能,研究了吸附过程的等温吸附特征、吸附动力学和热力学。结果表明,2种染料在TBFSC和ABFSC上的吸附更好地符合Langmuir等温方程,表观二级动力学模型能够很好地描述TBFSC和ABFSC的吸附动力学行为。对于染料在TBFSC上的吸附,粒子内扩散过程和液膜扩散过程是该吸附的速控步骤,而液膜扩散过程为ABFSC吸附染料的速控步骤。热力学参数表明,TBFSC和ABFSC对两种染料的吸附都是自发进行的物理吸附,吸附过程均无配位基交换、化学键等强的作用力。

We synthesized two composite adsorbents,namely tempered blast furnace slag-chitosan( TBFSC) and acid-modified blast furnace slag-chitosan( ABFSC),and used them to investigate the removal of acid anthraquinone blue and reactive brilliant red K-2BP from aqueous solution. Adsorption isotherms,kinetics and thermodynamics of two dyes on TBFSC and ABFSC were studied. The adsorption isotherms can be well described by the Langmuir equation. The adsorption kinetics follow the pseudo second-order kinetics model nicely. Adsorption rate of dyes on TBFSC is mainly governed by liquid film diffusion and intra-particle diffusion,while the adsorption rate of ABFSC is mainly governed by liquid film diffusion only. In addition,thermodynamic parameters show that adsorption of two dyes on TBFSC and ABFSC are spontaneous physical adsorption processes without strong acting force of concerted radical exchange and chemical bond.