【作者】 张彬；

【导师】 施周；

【作者基本信息】 湖南大学 ， 市政工程， 2003， 硕士

【摘要】 本文对纳米SiO₂分散液的性质及纳米SiO₂作为助凝剂去除水溶性有机物进行了研究。通过调节pH为7及超声波震荡10min后获得了一种纳米尺度的分散液。扫描电镜、透射电镜及激光粒度检测表明该溶液中有99％的SiO₂颗粒尺寸小于30nm，并且该分散液中的颗粒保持这一尺寸10小时。 选取三种代表不同分子量大小的有机物：腐殖酸（HA）、阴离子表面活性剂（SDS）及对氯酚作为典型有机污染物进行纳米SiO₂作为助凝剂的强化絮凝实验。对腐殖酸这一大分子有机物而言，试验结果表明，用硫酸铝作絮凝剂（20mg/L）及纳米SiO₂作为助凝剂（1mg/L）可以去除高达73％的腐殖酸，相对而言，没有纳米SiO₂作助凝剂的腐殖酸去除率只有30％。同样强化絮凝条件下，对比大分子腐殖酸，小分子的有机物SDS及对氯酚的去除率要低得多（＜8％），这一结果说明纳米SiO₂的强化絮凝对大分子物质更有效。 此外，pH值、温度、硫酸铝及纳米SiO₂的投加量能影响溶解性有机物的去除，对腐殖酸有较好去除的条件为：pH=5～9，硫酸铝投加量为20～40mg／L，SiO₂投加量为1～10mg／L。更多还原

【Abstract】 Characteristics of nano-SiO2 dispersions and application of nano-SiO2 as coagulation-aid in removal of dissolved organic pollutants were studied. A nano- SiO2 dispersion was obtained by adjusting of the dispersion to pH 7 and supersonic agitating it for 10 minutes. Results of SEM, TEM, and Laser seizer measurements indicated that there more than 99% of the SiO2 particles were less than 30 nm size. The dispersion could be stable with the particle size for 10 hours.Three organic compounds, humic acid(HA), anionic surfactant(SDS) and p-chlorphenol, representing different molecule size, were selected as typical organic pollutants for enhanced coagulation experiment with nano-SiO2 as the aid. For HA, a big molecule compound, results showed that it could be removed up to 73% by coagulation with Al2(SO4)3 (20mg/L) as coagulant and nano-SiO2 (Img/L) as the aid, comparing a lower removal of 30 % without the aiding of nano-SiO2 at the same conditions.Comparison to the big molecule compound HA, smaller molecule compounds SDS and p-chlorphenol, a much lower removal (less than 8%) was obtained under the same coagulation conditions with the aid of nano-sized SiO2 as the HA, indicating that the enhancement of nano-sized SiO2 was more effective for bigger molecule compound than the smaller ones.In addition, conditions such as pH volume, temperature, dosage of Al2(SO4)3 and SiO2, could also affect the removal of the dissolved organics. The suggested conditions for good removal of HA were pH 5-9, Al2(SO4)3 20mg/L, SiO2 1~10mg/L.更多还原