Long-term colloidal stability and metal leaching of single wall carbon nanotubes: Effect of temperature and extracellular polymeric substances
Long-term colloidal stability and metal leaching of single wall carbon nanotubes: Effect of temperature and extracellular polymeric substances
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DOI：
10.1016/j.watres.2013.11.032
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发表时间：
2014-02-01
期刊：
影响因子：
12.8
通讯作者：
Keller, Arturo A.
中科院分区：
文献类型：
--
作者：
Adeleye, Adeyemi S.;Keller, Arturo A.
研究了5种商用单壁碳纳米管(SWCNTs)在淡水、海水、雨水、废水和地下水中的长期稳定性(90天)、在有无天然有机物(NOM)存在和不存在的情况下的聚集动力学和金属浸出，以及温度对SWCNT稳定性和金属浸出的影响。随着温度的升高，单壁碳纳米管的Zeta(Zeta)电位呈下降趋势。在废水中，在40℃下保持30天后，SWCNT从水柱中沉淀到低于可检测的水平，但在20℃下，同样的暴露时间后仍观察到19%的悬浮液。添加0.1 mg-C的L-1EPS通过额外的静电和可能的空间稳定化将SRNOM稳定的单壁碳纳米管的临界凝血浓度从15 mM转移到54 mM NaC。单壁碳纳米管在水体中的附着效率(A)在含10 mg L的去离子溶液中为0.001，在海水中为1。然而，由于浮力和/或阻力的改善，单壁碳纳米管在海水(和其他高离子强度条件)中的沉积速度没有预期的那么快。纯化形式的单壁碳纳米管在大多数水域中表现出更好的分散性和稳定性，但正如预期的那样，原始变体中淋出的金属总量更高。在这些研究中，碳纳米管中金属的浸出受到金属和水的化学成分、碳纳米管的预处理、可浸出金属分数、暴露时间和NOM的存在的控制。(C)2013爱思唯尔有限公司。保留所有权利。
Long term (90 day) stability, aggregation kinetics in the presence and absence of natural organic materials (NOM), and metal leaching of five commercial single wall carbon nanotubes (SWCNTs) in waters (e.g. freshwater, seawater, stormwater, wastewater, and groundwater) were studied, as well as the effect of temperature on SWCNT stability and metal leaching. Zeta (zeta) potential of SWCNT decreased in magnitude with increase in temperature. In wastewater, SWCNT sedimented from the water column to below detectable levels after 30 days when kept at 40 degrees C, but at 20 degrees C 19% suspension was still observed after the same exposure time. Addition of 0.1 mg-C L-1 EPS shifted the critical coagulation concentration (CCC) of SRNOM-stabilized SWCNT from 15 mM to 54 mM NaCl via additional electrostatic and possibly steric stabilization. Attachment efficiencies (a) of SWCNT in waters ranged from 0.001 in DI with 10 mg L-1 SRNOM to 1 in seawater. However, sedimentation of SWCNT in seawater (and other high ionic strength conditions) was not as fast as expected due to improved buoyancy and/or drag. Purified forms of SWCNTs exhibited better dispersibility and stability in most waters, but as expected, the total metal leached out was higher in the raw variants. Metal leaching from CNT in these studies was controlled by metal and water chemistries, CNT pretreatment, leachable metal fraction, exposure time, and presence of NOM. (C) 2013 Elsevier Ltd. All rights reserved.