[关键词]
[摘要]
采用氯化铁和硫酸铝作为混凝剂,分别研究了不同形态结构的铜绿微囊藻、针杆藻和水华鱼腥藻的混凝效果及絮体特性。结果表明:在铁盐、铝盐混凝剂不同投加量下,铁盐对三种藻的混凝去除效果优于铝盐;三种藻在铁盐和铝盐各自达到最佳混凝效果时的混凝剂投加量:铁盐>铝盐。铜绿微囊藻的整体混凝效果最差,针杆藻的最好。相比于铝盐,三种藻在采用铁盐混凝时形成的藻絮体更密实且分形维数值也更大;针杆藻絮体的整体分形维数最大(最大值:1.72),铜绿微囊藻的最小(最大值:1.17),表明藻种形态对混凝絮体结构的影响。三种藻在采用铁盐混凝时的絮体粒径(d50)均大于铝盐絮体,絮体强度和恢复因子小于铝盐絮体的对应值。当采用铁盐混凝剂时,铜绿微囊藻絮体d50的最大值(632μm)小于针杆藻(765μm)和水华鱼腥藻(777μm);针杆藻絮体的恢复因子最大(26.54%),水华鱼腥藻的恢复因子最小(11.04%)。三种藻絮体到达等电点的铁盐投加量大于铝盐投加量,藻絮体Zeta电位可用于分析藻类混凝时最佳去除率对应的投加量。铜绿微囊藻以电性中和混凝机制为主,吸附架桥和网捕卷扫机制则可能对水华鱼腥藻和针杆藻的絮凝作用更重要。
[Key word]
[Abstract]
The coagulation effects and floc characteristics of M.aeruginosa, Synedra and Anabaena were studied, respectively, by using ferric chloride and aluminum sulfate coagulants. The results show that the ferric salt has better coagulation and removal effect on the three algae species than that of aluminum salt, and the optimal dosage of ferric salt coagulation is also greater than that of aluminum salt under different dosages of ferric and aluminum salts coagulant.The M.aeruginosa has the worst coagulation effect, and Synedra has the best under different dosages of ferric and aluminum salts. Compared with the use of aluminum salt, the three algae flocs coagulated by iron salt are denser and have larger fractal dimension. The fractal dimension value of Synedra is the largest(the maximum value:1.72) and that of M.aeruginosa is the smallest(the maximum value:1.17), indicating the effect of algae morphology on the flocs structure. The particle size(d50) of the three algae species when coagulated with ferric salt are larger than that of the flocs using aluminum salt, and the strength and recovery factor of the ferric salt flocs are smaller than that of the aluminum salt flocs. The maximum value of d50 of M.aeruginosa floc(632μm) is smaller than that of Synedra floc (765μm) and Anabaena floc(777μm) when using ferric salt. Synedra has the largest recovery factor of 26.54%, and Anabaena has the smallest recovery factor of 11.04% when using ferric salt. When the three algal flocs reach the isoelectric point, the dosage of ferric salt is greater than that of aluminum salt.The zeta potential of algal floc can be used to analyze the dosage corresponding to the optimal removal rate of algae coagulation. The M.aeruginosa flocculation is mainly electroneutralized, while the adsorption bridge and netting may play a more important role in the flocculation of Anabaena and Synedra.
[中图分类号]
TU991.2
[基金项目]
国家自然科学基金项目(面上项目,重点项目,重大项目)