水环境中不同浓度TiO₂纳米颗粒混凝工艺去除效果

王秀蘅, 龚小娟, 尤世界

(哈尔滨工业大学 城市水资源与水环境国家重点实验室, 150090 哈尔滨)



摘要:

为了探究水环境中不同质量浓度TiO₂ 纳米颗粒(NPs)混凝工艺去除影响因素及与浊度去除规律的区别,研究了在超声预处理后投加表面活性剂(LAS)对TiO₂ NPs分散稳定性的影响,通过烧杯实验分别考察了混凝剂(聚合氯化铝,PAC)投加量及pH对不同质量浓度TiO₂ NPs和浊度去除的影响,及pH对TiO₂ NPs表面Zeta电位的影响机制．结果表明,在250 W超声处理10 min后加入20 mg／L的LAS获得的纳米悬浮液稳定性最好;不同混凝剂投加量下,TiO₂ NPs和浊度的去除规律呈相近趋势,TiO₂ NPs初始质量浓度为0.5,1和2 mg／L时,PAC最优投加量为3 mg／L,对应TiO₂ NPs和浊度最大去除率分别为46.2％、60.2％、68.8％和23.2％、43.6％、47.6％．TiO₂ NPs初始质量浓度为5 mg／L时,PAC最优投量为4 mg／L,TiO₂ NPs和浊度最大去除率分别为77.64％和54.08％．pH对TiO₂ NPs表面Zeta电位有明显影响,进而影响TiO₂ NPs的去除效果．

关键词:  TiO₂纳米颗粒  混凝实验  浊度  去除率

DOI：10.11918/j.issn.0367-6234.2014.02.008

分类号:

基金项目:城市水资源与水环境重点实验室资助项目(2012DX05).



Removal of TiO₂ nanoparticles in water environment by coagulation process

WANG Xiuheng, GONG Xiaojuan, YOU Shijie

(State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, 150090 Harbin, China)

Abstract:

To inquiry the factors of removal efficiency of different-concentration TiO₂ NPs by coagulation processes and the difference between different-concentration TiO₂ NPs and turbidity in removal performance. This paper investigated the impact of sonication pretreatment and surfactant (LAS) on the stability of TiO₂ nanoparticles (NPs) in solution firstly, for getting dispersion stabilized suspension. We also studied the effect of dosage of coagulant (PAC) on different-concentration TiO₂ NPs based on jar test, and the dependence of surface zeta potential on pH.The results demonstrated that the best stability of TiO₂ NPs was obtained at sonication power of 250 W for 10 min under LAS concentration of 20 mg／L. The removal of TiO₂ NPs and turbidity exhibited the similar trends under various coagulant concentrations. The optimum coagulation dosage was 3 mg／L at initial TiO₂ NPs concentration of 0.5,1 and 2 mg／L, which corresponded to removing efficiency of TiO₂ NPs and turbidity of 46.2％, 60.2％, 68.8％ and 23.2％, 43.6％, 47.6％ respectively. The optimum coagulation dosage of 4 mg／L for initial TiO₂ NPs concentration of 5 mg／L resulted in removal of TiO₂ NPs and turbidity of 77.6％ and 54.1％. The pH value was found to have significant impact to Zeta potential, and then has influence on the removal effect of TiO₂ NP.

Key words:  TiO2 nanoparticles (NPs)  turbidity  coagulation experiment  removal rate