摘要
以富勒烯(C60)纳米颗粒稳定悬浮液为对象,采用动态光散射技术研究了天然有机物和电解质对其在水中凝聚行为的影响.结果表明,采用甲苯溶剂替换法制备的稳定悬浮液中C60浓度为20 mg·L-1左右,表面呈较高的电负性,粒径在120 nm左右,具有较强的稳定性.投加简单电解质可通过压缩双电层机制使其发生凝聚,并符合经典的胶体稳定性(DLVO)理论.Mg Cl2和Ca Cl2的临界凝聚浓度分别为9.6 mmol·L-1和6.7 mmol·L-1.腐殖酸(humic acid,HA)存在时,投加Na Cl和Mg Cl2可使C60颗粒间有效碰撞概率及凝聚反应速度降低,临界凝聚浓度提高;HA可通过增大C60颗粒间的空间位阻效应,抑制凝聚反应发生,提高其在水中的稳定性.但Ca2+可与HA间发生络合反应,并对C60纳米颗粒产生吸附架桥作用,导致凝聚速度大幅提高,强化凝聚反应发生.水中C60纳米颗粒的凝聚和分散行为将受到有机物性质和电解质种类等复杂因素的影响.
The effect of natural organic matter( NOM) and electrolytes on the aggregation of C60 nanoparticles in aquatic systems was studied by using dynamic light scattering. The results showed that the concentration of C60 stable suspension prepared by toluene solvent-exchange method was about 20 mg·L- 1. The C60 nanoparticles in the suspension showed a high zeta potential and particle diameter was around 120 nm. Addition of simple electrolytes induced aggregation of C60 nanoparticles through acompressing electric double layer,which was consistent with the classic Derjaguin-Landau-Verwey-Overbeek( DLVO) theory of colloidal stability. The critical coagulation concentration( CCC) values of Mg Cl2 and Ca Cl2 were 9. 6 and 6. 7 mmol·L- 1. In presence of humic acid,the addition of Na Cl and Mg Cl2 reduced the attachment efficiency and aggregation rate of C60 and increased CCCs. Humic acid enhanced the stability of C60 in water due to steric repulsion. However,the complexation reaction between Ca2 +and humic acid caused adsorption bridging with C60,which increased the aggregation rate and led to enhanced aggregation. This was identified as the primary mechanism of such enhanced aggregation behaviour. The aggregation and dispersion of C60 in water was influenced by the characteristics of organic matters,electrolyte species and other complex factors.
出处
《环境科学》
EI
CAS
CSCD
北大核心
2015年第10期3715-3719,共5页
Environmental Science
基金
国家自然科学基金项目(41401546)
江苏省普通高校研究生实践创新计划项目(SJLX_0388)
关键词
富勒烯(C60)
凝聚
天然有机物
电解质
有效碰撞概率
fullerene(C60)
aggregation
natural organic matter(NOM)
electrolytes
attachment efficiency
