穗花狐尾藻对镉的生物吸附特性研究  

Characteristics of cadmium biosorption onto Myriophyllum spicatum

作　　者：李国新[1] 陈国元[1] 李青松[1] 王蕾[1] 

机构地区：[1]厦门理工学院环境科学与工程学院,福建厦门361024

出　　处：《安全与环境学报》2013年第6期21-25,共5页Journal of Safety and Environment

基　　金：国家自然科学基金项目(51008261);福建省自然科学基金项目(2012J05030);厦门理工学院高层次人才引进项目(YKJ11028R)

摘　　要：沉水植物吸附处理低浓度重金属是一项清洁和廉价的技术。研究了接触时间、pH值、初始质量浓度、共存Ca2＋条件下,穗花狐尾藻对Cd的生物吸附特征。结果表明,穗花狐尾藻对Cd的吸附过程较快,在20 min内达到平衡。伪二级动力学方程能很好地拟合该吸附过程（R2=0.9996）,且Cd吸附量的模型计算值与实测值有很好的一致性（偏差控制在4.89%以下）。pH值显著影响穗花狐尾藻对Cd的吸附量。在初始Cd质量浓度为36 mg/L条件下,Cd吸附量在pH=5.0时达到最大（qe=17.73 mg/g）。与Freundlich模型相比,Langmuir模型对穗花狐尾藻吸附Cd有更好的拟合效果,表明穗花狐尾藻对Cd2＋的吸附属于单层吸附。Cd理论最大吸附量可达34.97 mg/g。运用Langmuir模型参数计算所得的Cd吸附量与其实测值有很好的一致性（除2个点的数据外,其余点的计算值与实测值差异控制在10%以下）。当温度为5-25℃时,升温有利于穗花狐尾藻对Cd的吸附。穗花狐尾藻对Cd的吸附属于自发的吸热过程。溶液中共存的Ca2＋不利于穗花狐尾藻对Cd的吸附。The paper is aimed at offering our analysis results on the characteristic features of cadmium biosorption onto Myriophyllum spi catum in hoping to utilize the submerged aquatic plants as a cheap and clean technique for remedying heavy metal contaminated water plants. It is for this purpose that we have studied the effects of con tact time, pH value, initial concentration of the heavy metal contami nants, and the calcium ions on the biosorption of cadmium via the Myriophyllum spicatum. The kinetic study shows that the cadmium biosorption rate of M. spicatum goes fast and that equilibrium can be reached in 20 rain. The overall absorption rate can be properly shown through a pseudosecond order model with a coefficient of determina tion of 0.999 6. The amount of the adsorbed cadmium worked out by using the pseudosecond order model proves to be consistent with what we have obtained with experiments with deviations less than 4.89% . In addition, the pH was＇found to elicit a significant effect on the cad mium biosorption of M. spicatum. If the initial cadmium concentra tion was set up at 36 mg/L, the specific adsorption capacity would be equal to 17.73 mg/g at pH 5.0. Compared with the Freundlich mod el, it turns out that the Langmuir model tends to be better fit for the biosorption of cadmium by M. spicatum, indicating that there exists a strong positive evidence that the biosorption followed the monolayer coverage of cadmium ions at the biomass surface. The maximum cad mium biosorption capacity for M. spicatum turns to be equal to 34.97 mg/g, whereas the amount of the adsorbed cadmium that was worked out by the Langmuir model should be in excellent consistency with that obtained experimentally （except for two data points, the cal culated data were very close to the experimental data, with deviations of less than 10% ）. Besides, the biosorption of cadmium by M. spi catum can be regarded as a thermodependent process, in which the cadmium biosorption capacity of M. spicatum increased with increas ing temperature. I

关 键 词：环境工程学 生物吸附 镉 穗花狐尾藻 LANGMUIR模型 

分 类 号：X703[环境科学与工程—环境工程]