磁核颗粒自生成的磁絮凝除藻特性

Characteristics of Algae Removal by Magnetic Flocculation of Self-generated Magnetic Particles

分别采用亚铁盐+铁盐(方案一)和亚铁盐+高锰酸钾(方案二)处理淡水蓝藻,研究在外磁场作用下2种方案对水中铜绿微囊藻的去除效果及机理。结果表明:在合适投药配比情况下,方案一、方案二在絮凝过程中分别自发生成磁核颗粒Fe3O4与MnFe2O4并实现藻絮体的快速磁分离,方案一对污染物的去除效率以及藻毒素的控制效果优于方案二,铁盐絮凝剂对藻团表面的亲水性EOM影响较小,KMnO4的强氧化作用使表层EOM脱落并损坏藻团结构从而造成藻毒素释放。水温、高岭土浓度以及藻絮体表面Zeta电位的变化对浊度和叶绿素的去除效果影响较小,TP去除受上述因素影响较大,且与藻絮体表面Zeta电位的变化趋势一致,可推断铜绿微囊藻和TP的主要去除机理分别为网捕卷扫作用和静电吸附作用。

Method one(ferrous salt+iron salt)and method two(ferrous salt+potassium permanganate)were employed to treat freshwater blue alga.The removal efficiency and mechanism of Microcystis aeruginosa from water under external magnetic field was studied.The results showed that under the condition of suitable dosage ratio,magnetic particles were formed spontaneously during flocculation of both methods and rapid magnetic separation of algae flocs was achieved,and the magnetic particles of method one and method two were Fe3O4 and MnFe2O4,respectively.The pollution removal rate and microcystin control of method one was better than that of method two.The ferrous and iron salts had little effect on the hydrophilic EOM of algae surface,but KMnO4 could make EOM fall off and damage the algal structure to cause release of microcystin.The changes of water temperature,kaolin concentration and zeta potential of algae floc surface had little effect on the removal of turbidity and Chl-a.The TP removal was greatly affected by the above factors and was consistent with the change trend of surface zeta potential.The main removal mechanism of Microcystis aeruginosa and TP could be catching-sweeping action and electrostatic adsorption,respectively.