芬顿试剂法制备磁性碳纳米管及其对亚甲基蓝的吸附性能

采用芬顿试剂法在碳纳米管纯化样品表面负载纳米磁性氧化铁颗粒,制备磁性碳纳米管杂化材料(MWCNTs/Fe2O3),该杂化材料具有较高的纳米氧化铁负载率(>50%)和优异的磁性能,制备过程中无需额外添加阳离子,不会对环境造成不利影响.将磁性碳纳米管杂化材料应用于染料废水处理中,结果发现MWCNTs/Fe2O3对亚甲基蓝染料吸附性能较好,吸附后用磁铁易于达到固液分离的效果.吸附性能研究表明,磁性碳纳米管对水溶液中亚甲基蓝的吸附在40 min内吸附容量迅速上升,其值达到最大平衡吸附容量的88%以上,60 min基本达到平衡,吸附过程符合准二级动力学模型(R2>0.999).磁性碳纳米管吸附亚甲基蓝的平衡吸附量qe与亚甲基蓝溶液的平衡浓度Ce的关系满足Langmuir(R2>0.999)、Freundlich(R2>0.97)以及Dubinin-Radushkevich(D-R)(R2>0.96)等温吸附模型.通过Langmuir模型计算可知磁性碳纳米管对亚甲基蓝的最大吸附容量为69.98 mg.g-1,吸附过程为有利吸附,由D-R模型计算结果可以推断MWCNTs/Fe2O3对水溶液中亚甲基蓝的吸附机制以化学吸附为主.

Adsorption of methylene blue on magnetic multiwalled carbon nanotube synthesized by Fenton reaction

In this paper,novel magnetic carbon nanotubes/iron oxide hybrids(MWCNTs/Fe2O3) were synthesized by Fenton reaction without the need of additional cations.The novel magnetic MWCNTs/Fe2O3 hybrid was used to remove methylene blue(MB) from aqueous solutions.Experimental results indicated that the MWCNTs/Fe2O3 hybrid has good adsorption capacity(qe) for MB,and the adsorbent was easily separated from aqueous solution after adsorption due to its magnetic properties.The adsorption of MB reached equilibrium within 40 minutes.The regression results showed that the adsorption kinetics were more accurately represented by pseudo second-order model(R2>0.999).The equilibrium adsorption data were analyzed using three widely applied isotherms: Langmuir,Freundlich and Dubinin-Radushkevich(D-R).The results suggested that all isotherm models can fit the experimental data reasonably well.Based on the Langmuir model,the maximum adsorption capacity of MWCNTs/Fe2O3 was 69.98 mg·g-1,and the adsorption process was favored.The adsorption of MB on the novel magnetic MWCNTs/Fe2O3 hybrids was mainly attributed to the chemical adsorption based on the D-R model.