Kao Wei-Chen, Wu Jane-Yii, Chang Chia-Che, Chang Jo-Shu
Department of Chemical Engineering, National Cheng Kung University, Tainan 701, Taiwan.
J Hazard Mater. 2009 Sep 30;169(1-3):651-8. doi: 10.1016/j.jhazmat.2009.03.140. Epub 2009 Apr 7.
Recombinant Escherichia coli expressing human metallothionein protein was immobilized with polyvinyl alcohol (PVA) for the removal of cadmium from solution. The adsorption ability was strongly affected by pH with optimal performance at pH 5.0, while it was less sensitive to temperature over the range of 20-42 degrees C. The adsorption kinetics and equilibrium of PVA-immobilized cells was best described by pseudo-second order model and Langmuir isotherm, respectively. Over the Cd concentrations range of 10-150 mg/l, PVA-cells had the highest Cd removal percentage (82.7%) at 10mg Cd/l and a biomass loading of 15.4 wt.%. Better adsorption ability was obtained when biomass loading was increased, as the highest adsorption capacity of 4.29 mg/g was achieved at 33.0 wt.% of biomass (initial Cd concentration=100mg/l). An aqueous solution of 0.01 M Na(3)NTA displayed the best desorption efficiency (57-89%) for four A/D cycles, while 51-61% of the original adsorption capacity was retained after regeneration.
表达人金属硫蛋白的重组大肠杆菌用聚乙烯醇（PVA）固定化，用于从溶液中去除镉。吸附能力受pH值影响很大，在pH 5.0时性能最佳，而在20-42摄氏度范围内对温度不太敏感。PVA固定化细胞的吸附动力学和平衡分别用伪二级模型和朗缪尔等温线来最好地描述。在Cd浓度为10-150 mg/l的范围内，PVA细胞在Cd浓度为10mg/l且生物量负载为15.4 wt.%时具有最高的Cd去除率（82.7%）。当生物量负载增加时，吸附能力增强，在生物量为33.0 wt.%（初始Cd浓度=100mg/l）时达到最高吸附容量4.29 mg/g。0.01 M Na(3)NTA水溶液在四个吸附/解吸循环中显示出最佳解吸效率（57-89%），再生后保留了51-61%的原始吸附容量。
