壳聚糖改性蛭石混凝除藻机理研究

Research on Mechanism of Coagulation to Remove Cyanobacteria by Chitosan Modified Vermiculite

文章对比了壳聚糖和改性蛭石对水华微囊藻的去除效果,通过Zeta电位、藻絮体形态分析探究改性蛭石混凝除藻机理。结果表明,单独壳聚糖投加量为1.8 mg/L时,浊度、藻密度和叶绿素a的去除率分别为93.21%、96.17%和95.63%;壳聚糖与蛭石投加比为1∶15(蛭石投加量为18 mg/L)时,絮凝效果最好,浊度、藻密度和叶绿素a的去除率分别达到95.16%、96.67%和100%,且生成的藻絮体更为密实、沉降性能更好、抗扰动性强。壳聚糖包裹在蛭石表面形成了正电性的改性蛭石,通过中和藻细胞表面电荷,使其脱稳聚集。藻絮体的显微、SEM图像和分形维数分析可得,改性蛭石混凝除藻过程中,藻絮体以蛭石为凝聚核,凝结成了内部为网状的凝聚团且其分形维数为1.832。

The removal effect of chitosan and modified vermiculite on cyanobacteria was compared.Zeta potential and algal floc morphology were used to investigate the mechanism of algae removal by modified vermiculite.Results showed that,when the dosage of chitosan was 1.8 mg/L,the removal rates of turbidity,algae density and chlorophyll a were 93.21%,96.17%and95.63%,respectively.It was achieved the best effect for algae removal,when the ratio of chitosan and vermiculite was 1∶15 with the vermiculite addition amount as 18 mg/L,the removal rates of turbidity,algal density and chlorophyll a were 95.16%,96.67%and 100%,and the treatment effect is better than chitosan alone.Chitosan is coated on the surface of vermiculite,and the surface charge of algae cells is eliminated or reduced by electrical neutralization,and the electric double layer is compressed to destabilize and aggregate.The algae floc uses vermiculite as a condensed nucleus and uses chitosan adsorption frame.The bridge acts to form a network of agglomerates,the generated floc were huge,dense and with good settling property,great performance in anti-turbulence.