文献类型：期刊文献

英文题名：Dispersion and stability of multi-walled carbon nanotubes in water as affected by humic acids

作者：Yang, Quanquan[1] Li, Xiaogang[1] Zhang, Luqing[2] Wang, Guojing[3] Chen, Guangcai[1] Lin, Daohui[2] Xing, Baoshan[4]

第一作者：Yang, Quanquan

通信作者：Chen, GC[1]|[a000551c9abd7c3960d59]陈光才;

机构：[1]Chinese Acad Forestry, Res Inst Subtrop Forestry, Hangzhou 311400, Zhejiang, Peoples R China;[2]Zhejiang Univ, Dept Environm Sci, Hangzhou 310058, Zhejiang, Peoples R China;[3]Chinese Res Inst Environm Sci, State Key Lab Environm Criteria & Risk Assessment, Beijing 100012, Peoples R China;[4]Univ Massachusetts, Stockbridge Sch Agr, Amherst, MA 01003 USA

年份：2019

卷号：279

起止页码：361-369

外文期刊名：JOURNAL OF MOLECULAR LIQUIDS

收录：;EI(收录号：20190606470001);Scopus(收录号：2-s2.0-85060930759);WOS:【SCI-EXPANDED(收录号:WOS:000462101800038)】；

基金：This work was funded by the National Natural Science Foundation of China (21207157, 21337004, 21477145, and 41771507). The authors thank both the anonymous reviewers for their constructive comments and Drs. Zhiguo Pei and Jiang Xiao for their kind help in revision, which significantly improved this manuscript.

语种：英文

外文关键词：MWCNTs; Humic acids; Steric hindrance; Electrostatic repulsion; Adsorption

摘要：The effects of two different humic acids (HAs), commercial Aldrich HA (AHA) and HA extracted from forest soils (FHA), on the dispersion and stability of three multi-walled carbon nanotubes (MWCNTs) in water were investigated. The amount of MWCNTs suspended in pure water increased with increases in the MWCNT surface oxygen content and solution pH, and the amount decreased as the ionic strength increased. These results indicated that electrostatic repulsion drove the dispersion of MWCNTs. Adsorbed HA greatly enhanced the dispersion and stability of MWCNTs due to the increased steric hindrance and electrostatic repulsion between individual MWCNTs. Suspended MWCNT concentrations and HA adsorption to MWCNTs were positively correlated with low ionic strengths (0-40 mM) and/or pH values between 3 and 7, which were independent of the change in electrostatic repulsion, suggesting that the dispersion of MWCNTs was primarily controlled by steric hindrance. At higher ionic strengths, MWCNTs rapidly precipitated due to the reduction of the electrostatic repulsion between individual MWCNTs. AHA could suspend more MWCNTs than FHA, which was ascribed to the higher molecular weight and aromatic carbon content of AHA that led to greater steric hindrance between individual MWCNTs. This result verified that steric hindrance was the dominant mechanism by which HAs disperse MWCNTs. (C) 2019 Elsevier B.V. All rights reserved.