轮叶黑藻对铅的吸附特征及生物吸附机理研究

研究了轮叶黑藻对重金属铅的吸附特征,同时对吸附机理进行探讨.动力学研究结果表明,轮叶黑藻对铅有较快的吸附能力,10min后铅的去除率达到74.54%;20min后,吸附达到平衡.整个吸附过程符合伪二级动力学方程(R2=0.9910).Sips和Langmuir模型相比Freundlich而言,有着较好的拟合效果,表明轮叶黑藻对重金属铅的吸附属于单层吸附,相邻铅离子间的相互干扰可以忽略不计.红外光谱分析表明:轮叶黑藻叶片富含多种活性基团,羟基、羰基和羧基、C–O及C–N为主要作用基团.吸附铅后,轮叶黑藻叶片内K、Na、Ca、Mg含量明显下降,表明铅离子因产生离子交换而被吸附,且铅离子更易与二价的Ca和Mg产生离子交换.

Characterization and mechanism studies on biosorption of lead onto Hydrilla verticallata

The characterization and mechanism of biosorption of lead onto H. verticallata were studied in this paper. The kinetic study showed that biosorption rate of lead(II) onto H. verticallata was fast as about 74.54% of total lead was removed within 10min and equilibrium was established within 20min. The overall sorption rate can be well fitted to the pseudo-second order model, with correlation of determination (R2) of 0.9910. Sips and Langmuir model were the better-fitting models for the biosorption of lead(II) onto H. verticallata than Freundlich model, which indicated that the biosorption of lead(II) onto H.verticallata follows monolayer coverage of lead(II) on the biomass surface and the interaction between lead molecules can be negligible. The FTIR spectra of biomass showed that there are lots of active groups on leaves of H. verticallata, and the possible functional groups responsible for lead(II) binding were carboxyl, hydroxyl, carbonyl groups, C–O and C–N. The concentration of mineral elements in leaves such as K, Na, Ca, Mg decreased after biosorption of lead, which indicated that lead(II) could be absorbed caused by ion exchanging with mineral elements.Furthermore,divalent elements such as Ca and Mg had better ion exchange capacity with lead ions.