不同官能团多壁碳纳米管对镉的吸附及细菌毒性

Adsorption of cadmium on multi-walled carbon nanotubes with different functional groups and their bacterial toxicity

【目的】探讨不同官能团多壁碳纳米管对镉离子(Cd^(2+))的吸附作用,揭示多壁碳纳米管影响镉细菌毒性的机制。【方法】通过批量吸附平衡实验研究不同官能团(羟基化、羧基化、氨基化、未经修饰)多壁碳纳米管(MWCNTs)对Cd^(2+)的吸附性能,通过细菌毒性实验评估不同官能团多壁碳纳米管和Cd^(2+)对大肠埃希菌Escherichia coli的毒性效应。【结果】4种多壁碳纳米管对Cd^(2+)的吸附能力从大到小依次为羧基化多壁碳纳米管、羟基化多壁碳纳米管、多壁碳纳米管、氨基化多壁碳纳米管,吸附性能与碳纳米管含氧量相关。多壁碳纳米管-Cd^(2+)复合物细菌毒性低于游离Cd^(2+),随纳米管质量浓度增加(0~200 mg·L^(-1)),羧基化多壁碳纳米管-Cd^(2+)复合物作用下细菌存活率从67%提高到81%。【结论】不同官能团多壁碳纳米管对Cd^(2+)的吸附量与碳纳米管含氧量呈正相关;多壁碳纳米管-Cd^(2+)复合物细菌毒性低于游离Cd^(2+),认为多壁碳纳米管可降低游离Cd^(2+)的细菌毒性。

[Objective]This study attempted to explore the adsorption properties of multi-walled carbon nanotubes(MWCNTs)with different functional groups for cadmium,and to reveal the influence mechanism on the bacterial toxicity of cadmium.[Method]The adsorption abilities of Cd^(2+)on MWCNTs with different functional groups(hydroxylated,carboxylated,aminated and unmodified)were studied by batch adsorption equilibrium test.The effects of MWCNTs with different functional groups on the toxicity of Cd^(2+)to Escherichia coli(E.coli)were evaluated by the bacterial toxicity test.[Result]The order of Cd^(2+)adsorption capacity on the four MWCNTs were carboxylated MWCNTs,hydroxylated MWCNTs,MWCNTs,finally aminated MWCNTs,which was related to the oxygen content.The combined bacterial toxicity of MWCNTs and Cd^(2+)was lower than that of free Cd^(2+),and the bacterial survival rate increased from 67%to 81%with the increasing carboxylated MWCNTs concentration(0-200 mg·L^(-1)).[Conclusion]The adsorption of Cd^(2+)by MWCNTs with different functional groups was positively correlated with their oxygen content.The combined bacterial toxicity of MWCNTs and Cd^(2+)was lower than that of free Cd^(2+),and it was concluded that MWCNTs could reduce the bacterial toxicity of free Cd^(2+).