有机污染物在碳纳米管上的吸附解吸动力学研究

Adsorption and desorption kinetics of organic contaminants on carbon nanotubes

为了分析研究有机物在碳纳米管上的吸附/解吸动力学机理,选用原始单壁碳纳米管(r-SWNTs)和氧化单壁碳纳米管(O-SWNTs)作为吸附剂,对比了2种碳纳米管对1,3-二氯苯(1,3-DCB)、2,4-二氯酚(2,4-DCP)和硝基苯(NBZ)3种不同污染物的吸附和解吸行为.研究结果表明:与非极性有机污染物相比,极性有机污染物具有相对较快的快吸附/解吸阶段和相对缓慢的慢吸附/解吸阶段.有机污染物在氧化碳纳米管上的吸附解吸动力学速率比在原始碳纳米管上缓慢,这主要是由于碳纳米管与有机污染物间的氢键和π-π电子供受体等的特殊作用所致.研究结果对碳纳米管在废水处理中的应用具有指导意义,同时可为评价碳纳米管的环境风险提供重要的技术参考.

In order to study the adsorption/desorption kinetics mechanism of organic contaminants on carbon nanotubes,the raw single-walled carbon nanotubes(r-SWNTs)and oxidized single-walled carbon nanotubes(O-SWNTs)were selected as the adsorbents,1,3-dichlorobenzene(1,3-DCB),2,4-dichlorophenol(2,4-DCP)and nitrobenzene(NBZ)were selected as the adsorbates,and the adsorption/desorption behaviors of these organic contaminants on r-SWNTs and O-SWNTs were compared. The results show that the rapid adsorption/desorption stage of the polar contaminants is relatively faster than that of nonpolar contaminants,and slow adsorption/desorption stage of the polar contaminants is relatively slower than that of nonpo-lar contaminants. The adsorption/desorption rate of all organic contaminants on O-SWNTs are slower than those on r-SWNTs.This is likely because of the specific interaction force(H-bonding,π-π electron donor-acceptor interactions,etc.)between organic contaminants and CNTs. It is important for CNTs in their application in wastewater treatment and assessment of their environmental risk.