金鱼藻对重金属Cr^(6+)的吸附特征研究

Research of Biosorption Characteristics of Cr^(6+) by Ceratophyllum demersum

采用Langmuir和Freundlich模型线性拟合方法研究了金鱼藻(Ceratophyllum demersum)对Cr6+的吸附等温线,分析了2种模型的拟合效果和适用性,结果表明:采用不同等温吸附模型评价植物对重金属的吸附时,根据拟合参数R2进行适用性判断并不准确,在实践中应结合实测数据与拟合模型重新计算获得的数据进行比较,并根据吸附反应本身的特点进行综合判断选择合适的吸附模型;沉水植物金鱼藻吸附Cr6+的行为在平衡质量浓度较低(c e<0.2mg/L)时,Freundlich模型拟合的效果更符合客观实际;在平衡质量浓度较高(ce>0.2mg/L)时,两种模型的拟合效果基本重合,均和实测数据较为吻合;根据Langmuir模型线性拟合参数,沉水植物金鱼藻对Cr6+的最大吸附量为1.5142×10-2 mg/g。

In this study,model linear fitting methods of Langmuir and Freundlich are carried out to investiga-tethe Cr^6＋ adsorption isotherms to Ceratophyllum demersum. And then the results and applicabilities of the two models are compared. The results show that： （1）When using different adsorption isotherm models to e-valuate the absortion of metals by plants,it is not accurate to use the fitting parameters R2 to judge the ap-plicability. In practice, it should compare the measured dates and the dates re-calculated with the fitting model,and also should take a comprehensive judgement to choose the most suitable model; （2）Submerged plant Ceratophyllum＇s adsorption behaviors at the lower （ce〈0.2mg/l） Cr^6＋ equilibrium concentrations are more in line with the realities by using Freundlich model. When the equilibrium concentrations are higher（ce 〉0.2mg/1） ,the two models are coincidence with the fitting results,they both are in line with the measured dates; （3）According to the Langmuir model linear regression parameters,the maximum adsorption of sub-merged plant Ceratophyllum to Cr^6＋ is 1.5142×10^-2mg/g.