表面活性剂与纳米SiO2作用下聚合铝的絮凝特性

在6NTU高岭土原水中,溶入低浓度溶解性有机物-阴离子表面活性剂(十二烷基硫酸钠,SDS),投加聚合铝PAC与新型水处理剂-纳米SiO2稳定分散液进行动态混凝实验与静止沉降实验.借助图像分析技术与分形理论,对SDS与纳米SiO2作用下PAC的絮凝特性与絮体分形结构的形态学特征进行研究.结果表明:存在SDS时,高岭土颗粒表面ζ电位增加.SDS在颗粒表面的吸附等温曲线符合Langmiur方程;PAC对无机颗粒的去除效果明显,但对SDS的表观去除率较低.SDS阻碍絮凝初絮体的形成.纳米SiO2使颗粒表面ζ电位增加,对无机颗粒处理效果较差,但对去除有机物有利.絮凝机理主要是吸附架桥;助凝剂纳米SiO2能促进PAC对无机颗粒与SDS絮凝,处理效果显著.悬浊液中絮体粒径大,有效质量密度增加,沉速加快,分维值下降.

Flocculation Properties of Polymeric Aluminium Chloride under Actions of Surfactant and Silica Dioxide Nanoparticles

Dynamic coagulation experiments and quiescent settling experiments were done by dissolving low concentration dissolvable organic material-anionic surfactants(Sodium Dodecyl Sulfate,SDS),and adding polyaluminium chloride (PAC) and a new water treatment chemical nano-silica dioxide stable dispersion solution to 6NTU Kaolin raw water respectively.The flocculation properties of PAC under actions of SDS and nano-particles of silica dioxide and morphological characteristics of flocs fractal structures were investigated by using image analysis technology and fractal theory.The results showed that Zeta potential on the surfaces of Kaolin particles increased with the presence of SDS.The adsorption isotherms of SDS on Kaolin particles followed the Langmiur equation;the removal efficiency of inorganic Kaolin particles with the presence of PAC in solution was higher compared with the low efficiency to SDS.SDS prevented flocs formation at the initial flocculation stage.Zeta potential on the surfaces of Kaolin particles increased with the presence of nanoparticles of silica dioxide.The removal efficiency of inorganic particles with the presence of nano-particles of silica dioxide in solution was poor but could produce a favorable result for the removal of the organic matter.Main flocculation mechanism was adsorption-bridging.The flocculant aid of silica dioxide nano-particles could dramatically promote the removal of inorganic particles and SDS.The flocs had a big size in suspension and an increased effective mass density and settling velocity,and a low value of fractal dimension.