水华蓝藻胞外聚合物对高岭土吸附罗丹明B行为的影响

Effect of Bloom-Forming Cyanobacterial Extracellular Polymeric Substances on Adsorption Performance of Rhodamine B by Kaolinite

蓝藻水华爆发时期会在水中产生大量的蓝藻胞外聚合物(EPS),然而蓝藻水华EPS对于有机染料在水体与沉积物界面之间的影响尚不明确。在实验室条件下利用提取的微囊藻EPS,研究其对高岭土吸附罗丹明B的影响。试验证明,EPS能促进高岭土对罗丹明B的吸附,吸附动力学与伪一级动力学拟合,高岭土与高岭土-EPS复合体的拟合相关系数R^2分别为0.846 7和0.950 1。等温吸附以Langmuir和Freundlich拟合,结果更符合Freundlich吸附模型。不同pH条件下的吸附试验结果表明,罗丹明B在酸性条件下更容易被吸附。

Cyanobacterial blooms can result in high level of cyanobacterial extracellular polymeric substances （ EPS） in water. Whereas,the effects of bloom-forming cyanobacterial EPS on the distribution of organic dyes in the interface between sediments and water are still unknown. The effects of EPS （originate from a typical bloom-forming cyanobacterium Microcystis aeruginosa,which are extracted in laboratory conditions） on the adsorption characteristics of Rhodamine B by kaolinite are investigated. The results indicate that EPS can facilitate adsorption Rhodamine B by kaolinite. The kinetics of adsorption is fitted by pseudo first-order kinetics, and R2 for kaolinite and kaolinite-EPS composites are 0.846 7 and 0.950 1, respectively. Isothermal adsorption is fitted with Langmuir and Freundlich model, and the results are in good agreement with Freundlich adsorption model. Results of adsorption behavior under different pH value indicate that Rhodamine B is more easily adsorbed under acidic conditions.