Zn-MOF-74对Cd(Ⅱ)的吸附性能及机理研究

Adsorption performance and mechanism of Cd(Ⅱ) onto Zn-MOF-74

研究了新型吸附材料Zn-MOF-74对水体中重金属Cd(Ⅱ)的吸附性能和吸附机理。结果表明,吸附过程较好地符合Langmuir模型、Temkin模型、D-R模型和准二级动力学模型,最大吸附量为16.77 mg/g;吸附过程为物理吸附和化学吸附共同作用,且为自发的放热反应。采用Zn-MOF-74处理0.5 mg/L的含镉废水,有效时长可达36.25 h,Cd(Ⅱ)去除率>90%;NaCl溶液的解吸率可达到85%。吸附位点主要集中在孔道中,有静电作用、化学作用和氢键作用。

This paper was aimed at studying the performance and mechanism of Zn-MOF-74,a new porous adsorbent material,for removing heavy metal cadmium in water.The results showed that the static adsorption process accorded with Langmuir,Temkin,D-R and pseudo-second-order models,and the maximum adsorption capacity was 16.77 mg/g.The adsorption process was a combination of physical adsorption and chemical adsorption with a self-heating reaction.In the dynamic adsorption experiment,the Cd(Ⅱ)removal rate of 90%was achieved within 36.25 h for degrading the cadmium the initial concentration of 0.5 mg/L.Additionally,the desorption rate reached 85%in 0.25 mol/L NaCl solution.The adsorption sites were mainly concentrated in the micropores and mesopores by electrostatic action,chemical action and hydrogen bonding.