Removal of dispersant-stabilized carbon nanotubes by regular coagulants  

作　　者：Ni Liu Changli Liu Jing Zhang Daohui Lin 

机构地区：[1]Department of Environmental Science,Zhejiang University,Hangzhou 310058,China [2]Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control,Hangzhou 310058,China

出　　处：《Journal of Environmental Sciences》2012年第8期1364-1370,共7页环境科学学报（英文版）

基　　金：supported by the National Basic Research Program (973) of China (No. 2008CB418204);the National Natural Science Foundation of China (No. 21077089,40873072);the Zhejiang Provincial "Qianjiang Talent Program" (No. 2010R10041);Zhejiang Provincial Innovative Research Team of Water Treatment Functional Materials and their Application

摘　　要：Coagulation followed by sedimentation, as a conventional technique in the water treatment plant, can be the first line of defense against exposures of carbon nanotubes （CNTs） to aquatic organisms and human beings, which has been rarely documented. This study investigated the removal of dispersant-stabilized CNT suspensions by poly aluminum chloride （PAC1） and KAl（SO4）2-12H20 （alum）, with a focus on the effects of dispersant type, coagulant type and dosage. PAC1 performed better than alum in the removal of tannic acid-, humic acid-, and sodium dodecyl benzenesulfonate-stabilized CNTs, but worse for polyethylene glycol octylphenyl ether （TX100）-stabilized CNTs. Neither coagulant could effectively precipitate cetyltrimethyl ammonium bromide-stabilized CNTs. The removal by PACl first increased up to a plateau and then decreased with the continued increase of coagulant dosage. However, the removal rates leveled off but did not decrease after achieving their highest level with the continued addition of alum. The coagulation and flocculation of the CNT suspensions by PACl could be regulated mainly by the mechanism of adsorption charge neutralization, whereas the coagulation by alum mainly involved electrical double-layer compression.Coagulation followed by sedimentation, as a conventional technique in the water treatment plant, can be the first line of defense against exposures of carbon nanotubes （CNTs） to aquatic organisms and human beings, which has been rarely documented. This study investigated the removal of dispersant-stabilized CNT suspensions by poly aluminum chloride （PAC1） and KAl（SO4）2-12H20 （alum）, with a focus on the effects of dispersant type, coagulant type and dosage. PAC1 performed better than alum in the removal of tannic acid-, humic acid-, and sodium dodecyl benzenesulfonate-stabilized CNTs, but worse for polyethylene glycol octylphenyl ether （TX100）-stabilized CNTs. Neither coagulant could effectively precipitate cetyltrimethyl ammonium bromide-stabilized CNTs. The removal by PACl first increased up to a plateau and then decreased with the continued increase of coagulant dosage. However, the removal rates leveled off but did not decrease after achieving their highest level with the continued addition of alum. The coagulation and flocculation of the CNT suspensions by PACl could be regulated mainly by the mechanism of adsorption charge neutralization, whereas the coagulation by alum mainly involved electrical double-layer compression.

关 键 词：water treatment COAGULANTS NANOMATERIAL SURFACTANT natural organic matter 

分 类 号：X703.1[环境科学与工程—环境工程] TB383[一般工业技术—材料科学与工程]