Hammaini A, González F, Ballester A, Blázquez M L, Muñoz J A
Dpto. de Ciencia de los Materiales e Ingeniería Metalúrgica, Facultad de Ciencias Químicas, Universidad Complutense, Ciudad Universitaria, 28040 Madrid, Spain.
J Environ Manage. 2007 Sep;84(4):419-26. doi: 10.1016/j.jenvman.2006.06.015. Epub 2006 Sep 18.
The biosorption of different metals (Cu2+, Cd2+, Zn2+, Ni2+ and Pb2+) was investigated using activated sludge. The optimum pH was 4 for Cd, Cu and Pb sorption and 5 for Ni and Zn. Biomass metal uptake clearly competed with protons present in the aqueous medium, making pH an important variable in the process. Protons consumed by biomass in control tests versus protons exchange in biosorption tests confirmed a maximum exchange between metal cations and protons at pH 2. The study of the influence of biomass concentration revealed that the amount of protons released from biomass increased with biomass concentration. This would confirm the hypothesis of ion exchange between both types of ions. The application of the Langmuir and Freundlich models showed a better fitting of experimental data to the first model. The maximum sorption uptake of the studied metals by the activated sludge showed the following decreasing order: Pb>Cu>CdZn>Ni. Desorption experiments showed that HCl was a good eluent for the five metals tested, particularly at low pH values (1 and 2). At pH 3 or 4 the desorption yield was significantly lower. However, its use did not allow the reuse of biomass in subsequent loading and unloading cycles. EDTA was also a good desorption agent, achieving the total recovery for the five metals tested at a concentration of 1mM, with the advantage that biomass could be reused for three sorption-desorption cycles.
使用活性污泥研究了不同金属（Cu2+、Cd2+、Zn2+、Ni2+和Pb2+）的生物吸附。Cd、Cu和Pb吸附的最佳pH值为4，Ni和Zn吸附的最佳pH值为5。生物质对金属的吸收明显与水介质中存在的质子竞争，使得pH成为该过程中的一个重要变量。对照试验中生物质消耗的质子与生物吸附试验中的质子交换情况证实，在pH为2时金属阳离子与质子之间的交换达到最大值。对生物质浓度影响的研究表明，生物质释放的质子数随生物质浓度的增加而增加。这将证实两种离子之间离子交换的假设。Langmuir模型和Freundlich模型的应用表明，实验数据与第一个模型的拟合效果更好。活性污泥对所研究金属的最大吸附量呈现以下递减顺序：Pb>Cu>Cd>Zn>Ni。解吸实验表明，HCl是所测试的五种金属的良好洗脱剂，特别是在低pH值（1和2）时。在pH为3或4时，解吸率显著降低。然而，使用HCl后生物质无法在后续的加载和卸载循环中重复使用。EDTA也是一种良好的解吸剂，在浓度为1mM时可实现对所测试的五种金属的完全回收，其优点是生物质可用于三个吸附-解吸循环。
