蓖麻秸秆对铅、汞、镍和镉的吸附特征

Study on kinetics and thermodynamics of Pb^(2+),Hg^(2+),Cd^(2+),and Ni^(2+) adsorption onto castor straw

以蓖麻秸秆粉末为吸附剂,采用批量平衡法,研究固液比、pH、重金属离子初始质量浓度对蓖麻秸秆粉末吸附Pb,Hg,Cd和Ni离子的影响,探讨蓖麻秸秆粉末对4种重金属离子的等温吸附和吸附动力学特征。结果表明:Langmuir、Freundlich和Temkin模型能更好地描述蓖麻秸秆粉末对Pb的吸附,Langmuir和Temkin模型能更好地描述蓖麻秸秆粉末对Hg和Cd的吸附,Langmuir模型能更好地描述蓖麻秸秆粉末对Ni的吸附;蓖麻秸秆粉末对4种重金属离子的最大吸附量分别是209.60、129.41、62.78和25.86mg/g;准一级动力学、准二级动力学和叶洛维奇方程能很好地描述蓖麻秸秆粉末对Pb,Hg,Cd和Ni离子的吸附过程。蓖麻秸秆粉末可用于处理多种重金属离子污染的废水。

Castor straw was used to remove Pb, Hg, Cd, and Ni from aqueous solution as an adsorbent by bath adsorption experiments. The effect of solid-liquid ratio, pH and initial heavy metal concentrations on the removal of heavy metals was investigated. Isotherm adsorption and kinetic characteristics were also discussed. The results showed that the adsorption parameters of Pb well followed Langmuir model, Freundlich model and Temkin model. The adsorption parameters of Hg and Cd well followed the Langmuir model and Temkin model. And the adsorption parameters of Ni well followed the Langmuir model;The adsorption kinetics of heavy metal ions could be described by the pseudo-first order model,pseudo-second order model and Elovich model; The maximum adsorption onto castor straw capacities were 209.60 mg/g Pb2＋ , 129.41 mg/g Hg2＋ , 62.78 mg/g Cd2＋ ,25.86 mg/g Ni2＋ , respectively. In conclusion, the castor straw was effective for the removal of heavy metals from multi-metallic mixture aqueous solutions.