Tuzen Mustafa, Sari Ahmet, Mendil Durali, Uluozlu Ozgur Dogan, Soylak Mustafa, Dogan Mehmet
Department of Chemistry, Gaziosmanpasa University, Tokat, Turkey.
J Hazard Mater. 2009 Jun 15;165(1-3):566-72. doi: 10.1016/j.jhazmat.2008.10.020. Epub 2008 Oct 14.
Arsenic (As) is generally found as As(III) and As(V) in environmental samples. Toxicity of As(III) is higher than As(V). This paper presents the characteristics of As(III) biosorption from aqueous solution using the green algae (Ulothrix cylindricum) biomass as a function of pH, biomass dosage, contact time, and temperature. Langmuir, Freundlich and Dubinin-Radushkevich (D-R) models were applied to describe the biosorption isotherm of As(III) by U. cylindricum biomass. The biosorption capacity of U. cylindricum biomass was found as 67.2mg/g. The metal ions were desorbed from U. cylindricum using 1M HCl. The high stability of U. cylindricum permitted 10 times of adsorption-elution process along the studies with a slightly decrease about 16% in recovery of As(III) ions. The mean free energy value evaluated from the D-R model indicated that the biosorption of As(III) onto U. cylindricum biomass was taken place by chemical ion-exchange. The calculated thermodynamic parameters, DeltaG degrees , DeltaH degrees and DeltaS degrees showed that the biosorption of As(III) onto U. cylindricum biomass was feasible, spontaneous and exothermic under examined conditions. Experimental data were also tested in terms of biosorption kinetics using pseudo-first-order and pseudo-second-order kinetic models. The results showed that the biosorption processes of As(III) followed well pseudo-second-order kinetics.
在环境样品中，砷（As）通常以三价砷（As(III)）和五价砷（As(V)）的形式存在。As(III)的毒性高于As(V)。本文介绍了以绿藻（圆柱鞘丝藻）生物质为吸附剂，从水溶液中吸附As(III)的特性，该特性是pH、生物质用量、接触时间和温度的函数。应用朗缪尔（Langmuir）、弗伦德利希（Freundlich）和杜比宁-拉杜舍维奇（Dubinin-Radushkevich，D-R）模型来描述圆柱鞘丝藻生物质对As(III)的生物吸附等温线。发现圆柱鞘丝藻生物质的生物吸附容量为67.2mg/g。使用1M盐酸从圆柱鞘丝藻中解吸金属离子。圆柱鞘丝藻的高稳定性使得在整个研究过程中可以进行10次吸附-洗脱过程，As(III)离子的回收率略有下降，约为16%。从D-R模型评估的平均自由能值表明，As(III)在圆柱鞘丝藻生物质上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，在研究条件下，As(III)在圆柱鞘丝藻生物质上的生物吸附是可行的、自发的且放热的。还使用伪一级和伪二级动力学模型对实验数据进行了生物吸附动力学测试。结果表明，As(III)的生物吸附过程符合伪二级动力学。
