多壁碳纳米管吸附去除水中1,2,3 - 三氯苯

采用3种不同直径的多壁碳纳米管(MWNTs)对1,2,3 - 三氯苯(TCB)进行吸附实验.结果表明,随MWNTs直径减小,1,2,3 - 三氯苯吸附量增加.实验中发现MWNT(L-8)对TCB的吸附仅需150 min就能基本达到平衡,且最大吸附量达77.5 mg/g;其吸附动力学和热力学过程可分别用假二级反应动力学模型和Freundlich吸附等温线模型来描述.在278 K±1 K,288 K±1 K和298 K±1 K下进行的MWNT(L-8)吸附热力学实验所得到的如平衡常数(K~0)、吉布斯自由能(ΔG~0)、标准焓变(ΔH~0)、熵变(ΔS~0)等热力学参数表明,MWNTs吸附TCB过程为自发吸热反应.当pH值在2～11之间变化时,吸附量基本不变,表明H键对MWNTs吸附TCB过程无显著影响,MWNTs对TCB的强吸附作用可能是MWNTs表面存在的π电子与TCB苯环中的π电子形成π电子对的作用结果.

Study of the Adsorptive Removal of 1,2,3 - Trichlorobenzene from Water Using Multi-wall Carbon Nanotubes

Three kinds of multi-walled carbon nanotubes (MWNTs) with different diameters were tested for the adsorption of 1,2,3-trichlorobenzene (TCB) from water. Results showed that the adsorption quantity of the tested TCB increased with the decrease of the diameter of MWNTs. Further experiments demonstrated that it took only 150 min for MWNT(L-8) to attain equilibrium, and the maximal adsorption capacity was 77.5mg/g. The adsorption kinetics and isotherm could be well described with a pseudo-second-order rate model and Freundlich isotherm respectively. The adsorption thermodynamics of 1,2,3 - Trichlorobenzene on the MWNT(L-8) was carried out at 278 K±1 K,288 K±1 K,298 K±1 K, respectively.And the thermodynamic parameters, such as equilibrium constant(K~0), standard free energy changes(ΔG~0), standard enthalpy change(ΔH~0) and standard entropy change(ΔS~0), were obtained, indicating that the adsorption of the TCB on the MWNT was spontaneous and endothermic. The fact that the variation of pH from 2 to 11 had little effect on the TCB adsorption on the MWNT showed that the H bond between TCB and MWNT did not play much role, while the π electronics on the surface of MWNTs and TCB benzene ring might be coupled and acted as a strong adsorption force.