悬浮液中硫酸根对改性粘土去除藻华生物效率的影响

本文研究了改性粘土悬浮液中硫酸根对其去除藻华生物效率的影响,通过Zeta电位、沉降速率和粒径分布等分析了改性粘土对藻华生物的去除效率,探讨了硫酸根与改性粘土的作用机制。结果显示:改性粘土对抑食金球藻(Aureococcus anophagefferens)的去除效率随悬浮液中硫酸根浓度的增加呈现先降低后升高的趋势,改性湖北土和改性江苏土对抑食金球藻去除率较低时(40%)的硫酸根浓度分别为6.46×10–3—2.42×10–1mol/L和6.46×10–3—2.42×10–2mol/L;改性粘土颗粒的Zeta电位随着硫酸根浓度的增加而降低,然后保持相对稳定;悬浮液中改性粘土颗粒的沉降速率和中值粒径D50呈现先增加后降低的趋势,对于改性江苏土,在硫酸根浓度为2.42×10–2mol/L时颗粒的沉降速率最大。综上所述,悬浮液中硫酸根主要通过降低粘土颗粒表面电荷密度、桥联改性粘土组分和影响粘土颗粒分散性等作用影响改性粘土对藻华生物的去除效率。

EFFECTS OF SULFATE ION IN SUSPENSION ON MODIFIED CLAY PARTICLES IN REMOVING HARMFUL ALGAL ORGANISMS

In present study, we investigated the effects of sulfate ion in suspension on modified clay particles in removing brown tide organism Aureococcus anophagefferens. Zeta potentials,size distribution and coagulation rates were employed to study the mechanism of sulfate ion on modified clay particle behaviors. Correlations between zeta potential, coagulation rates and removal efficiency were also analyzed respectively. Our results showed that with increasing concentration of sulfate ion in modified clay suspension, the removal efficiency of modified clay on Aureococcus anophagefferens decreased gradually and then increased. The removal efficiency was low (<40%) when the concentration of sulfate ion in suspension was between 6.46E-3~2.42E-1mol/L and 6.46E-3~2.42E-2mol/L for GXHB clay and GXJS clay respectively. The Zeta potential of the modified clay particle decreased gradually with increasing concentration of sulfate ion, and then remained stable. Zeta potential of clay particles was positively correlated with the removal efficiency of Aureococcus anophagefferens by modified clay. The coagulation rates and median size D50 rose gradually, and then decreased gradually. The coagulation rates reached the maximum at the sulfate ion concentration of 2.42E-2 mol/L for GXJS clay. The effects of sulfate ion on properties of modified clay suspension were caused by decreasing the surface charge density on modified clay particles, interacting with the ingredient of modified clay and affecting the transformation of the hydrolysis production, etc.