Sari Ahmet, Mendil Durali, Tuzen Mustafa, Soylak Mustafa
Department of Chemistry, Gaziosmanpasa University, Tokat 60250, Turkey.
J Hazard Mater. 2009 Mar 15;162(2-3):874-9. doi: 10.1016/j.jhazmat.2008.05.112. Epub 2008 May 28.
The biosorption potential of Racomitrium lanuginosum as aquatic moss biosorbent for the removal of Pd(II) from aqueous solution was investigated. The effects of pH, biomass dosage, contact time, and temperature on the biosorption processes were systematically studied. Experimental data were modeled by Langmuir, Freundlich and Dubinin-Radushkevich (D-R) isotherms. Langmuir isotherm model (R(2)=0.994) fitted the equilibrium data better than the Freundlich isotherm model (R(2)=0.935). The monolayer biosorption capacity of R. lanuginosum biomass for Pd(II) was found to be 37.2mg/g at pH 5. The mean free energy was calculated as 9.2 kJ/mol using the D-R isotherm model (R(2)=0.996). This result indicated that the biosorption of Pd(II) was taken place by chemical ion-exchange. The calculated thermodynamic parameters, DeltaG degrees , DeltaH degrees and DeltaS degrees showed that the biosorption of Pd(II) on R. lanuginosum biomass was feasible, spontaneous and exothermic under examined conditions. Experimental data were also tested using the biosorption kinetic models. The results showed that the biosorption processes of Pd(II) on R. lanuginosum followed well pseudo-second-order kinetics at 20-50 degrees C (R(2)=0.999).
研究了毛棉藓作为水生苔藓生物吸附剂从水溶液中去除钯（II）的生物吸附潜力。系统研究了pH值、生物量剂量、接触时间和温度对生物吸附过程的影响。实验数据采用朗缪尔、弗伦德利希和杜宾宁-拉杜舍维奇（D-R）等温线进行建模。朗缪尔等温线模型（R² = 0.994）比弗伦德利希等温线模型（R² = 0.935）能更好地拟合平衡数据。在pH值为5时，毛棉藓生物量对钯（II）的单层生物吸附容量为37.2mg/g。使用D-R等温线模型（R² = 0.996）计算出平均自由能为9.2 kJ/mol。该结果表明钯（II）的生物吸附是通过化学离子交换进行的。计算得到的热力学参数ΔG°、ΔH°和ΔS°表明，在考察条件下，钯（II）在毛棉藓生物量上的生物吸附是可行的、自发的且放热的。实验数据也使用生物吸附动力学模型进行了测试。结果表明，在20 - 50℃下，钯（II）在毛棉藓上的生物吸附过程很好地遵循拟二级动力学（R² = 0.999）。
