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以聚合氯化铝PAC为混凝剂,纳米SiO2为助凝剂,对含有下列微污染物:十二烷基硫酸钠(SDS)、氨氮(NH3-N)或腐植酸(HA)的高岭土悬浊液进行混凝沉降实验。借助形态学理论、电镜观察与图像分析技术,研究纳米SiO2对微污染物的助凝作用效果、吸附特性与絮体结构的形态学特征。结果表明:(1)在含有HA、SDS、NH3-N的模拟原水中,污染物去除率与浊度去除率的相关性随污染物分子量的增大而增强;(2)纳米SiO2对HA、SDS及NH3-N的助凝吸附效果,随分子量的降低而减弱。纳米SiO2能促使PAC对HA、SDS与NH3-N的去除率分别提高40%～50%、20%～30%和10%～15%;(3)纳米SiO2能促使PAC作用下的絮体粒径增大、密实度和分维值增加、沉速加快。
Using polyaluminum chloride (PAC) as coagulant and nano-SiO2 as coagulant, kaolin suspension containing the following micro-pollutants: sodium dodecyl sulfate (SDS), ammonia nitrogen (NH3-N) Turbid fluid coagulation experiments. Morphological theory, electron microscopy and image analysis techniques were used to study the effect of nano-SiO2 on the coagulation-promoting effect of micro-pollutants, the adsorption characteristics and the morphological characteristics of floc structure. The results show that: (1) The correlation between pollutant removal rate and turbidity removal rate increases with the increase of molecular weight of pollutants in simulated raw water containing HA, SDS and NH3-N; (2) SDS and NH3-N coagulant adsorption effect, with the molecular weight decreased. Nano-SiO2 can promote the removal of HA, SDS and NH3-N by PAC by 40% -50%, 20% -30% and 10% -15%, respectively. (3) The diameter increases, the density and the fractal dimension increase, sinks quickly.