摘要
作为一种新型的碳质纳米材料,碳纳米管因其独特的物理和化学性能被广泛应用于各种高性能材料或器件.碳纳米管一旦被排放到水体中,因其巨大的比表面积将导致水环境中共存物质形态的改变,碳纳米管自身的赋存状态也将因共存物质的吸附而改变,从而直接或间接影响所在水体的毒理学特性.因此,有关碳纳米管聚集和沉降行为的研究对预测和评价其在自然水体中的环境效应具有重要的意义.本文通过描述胶体稳定性的经典Derjaguin-Landau-Verwey-Overbeek(DLVO)作用力和非DLVO作用力,并借助时间分辨的动态光散射、石英晶体微天平和柱过滤测试,探讨了碳纳米管在水溶液中的聚集和沉降动力学,分析了碳纳米管的结构特性、电解质、溶液pH和天然有机质等因素对碳纳米管在水溶液中分散稳定性的影响及原因,阐明了控制碳纳米管颗粒在水溶液中聚集和沉降行为的作用机制,指出了在碳纳米管的聚集和沉降行为研究中存在的技术难点,并对未来碳纳米管的实验研究进行了展望.
As a novel nanoscale carbonaceous materials,carbon nanotubes（CNTs）have attracted extensive interests.Due to their unique electronic,optical,thermal,and mechanical properties,CNTs have been an ideal materials for industrial application.The ever rising demand and the decreasing cost lead to increased release of CNTs into natural waters.Once exposed to water environment,owing to their large specific surface areas,CNTs will inevitably adsorb the coexsited organic contaminations.Due to their nanoscale,CNTs are easily penetrated into human body,thus becoming a latent threat to both the environment and human being.The bioavailability and the toxicity of CNTs largely depend on their particle size in aquatic environment.In other words,the dispersion stability of CNTs is a key factor in determining their transport and fate in aquatic environment.Therefore,studies on the aggregation and deposition behavior of CNTs is of great significance to predict their environmental effects on water bodies.In this review,the mechanisms for the aggrega-tion and deposition behaviors of CNTs were elucidated by describing the interactions between CNT colloidals with the classical Derjaguin-Landau-Verwey-Overbeek（DLVO）theory and the non-DLVO forces.The aggregation and deposition kinetics of CNTs were probed with the aid of time-resolved dynamic light scattering,quartz crystal microbalance,and column filtration analysis.The effects of some influencing factors,such as the physiochemical properties of CNTs（diameter,length,the content of surface functional groups）,ionic strength,solution pH,and natural organic matters,on the dispersion stability of CNTs were evaluated.Moreover,the main difficulties in the study of the aggregation and deposition behavior of CNTs were pointed out.The complexity of matters in natural water and the lack of suitable experimental approach aggravated the difficulties in the current investigation on CNTs.The possible development of experimental research on CNTs in the near future was put forward.
出处
《南京大学学报（自然科学版）》
CAS
CSCD
北大核心
2014年第4期405-413,共9页
Journal of Nanjing University（Natural Science）
基金
国家自然科学基金(21107045)
江苏省自然科学基金(BK2011575)
教育部新世纪优秀人才支持计划(NCET-10-0489)
关键词
碳纳米管
聚集
沉降
DLVO理论
影响因素
carbon nanotubes
aggregation
deposition
DLVO theory
influencing factor
