改性碳纳米管原始样品吸附亚甲基蓝的性能研究

利用直接制备的碳纳米管原始样品作为染料亚甲基蓝的吸附剂,采用次氯酸钠溶液对于碳纳米管原始样品进行表面修饰改性,改性处理后碳纳米管对亚甲基蓝吸附性较好,本工艺简单有效,所获得的吸附剂具有磁性,吸附过后用磁铁易于达到固液分离的效果.吸附性能结果表明:本吸附剂对水溶液中亚甲基蓝的吸附在60 min基本达到平衡,吸附过程符合准二级动力学模型(R2>0.99).改性后的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>0.99)、Freundlich(R2>0.91)以及Dubinin-Radushkevich(D-R)(R2>0.92)等温吸附模型.通过Langmuir模型计算可知改性磁性碳纳米管对亚甲基蓝的最大吸附容量为101.6 mg.g-1,由D-R模型计算结果可以推断,次氯酸钠改性后的磁性碳纳米管对水溶液中亚甲基蓝的吸附机理以化学吸附为主.

Adsorption of methylene blue on the modified as-prepared carbon nanotubes

In this paper,the adsorption of methylene blue(MB) in water was investigated using as-prepared magnetic carbon nanotubes(mCNTs) modified by NaClO.In particular,the adsorption capacity of modified mCNTs for MB was high.This method to remove MB was simple and effective.The new adsorbent was easily separated from aqueous solution after adsorption due to its magnetic properties.The adsorption of MB reached equilibrium within 60 minutes.Kinetic analyses were conducted using pseudo first- and second-order models and the intra-particle diffusion model.The regression results showed that the adsorption kinetics were more accurately represented by pseudo second-order model(R2>0.99).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 modified mCNTs was 101.6 mg·g-1,and the adsorption process was favored.The adsorption mechanism of mCNTs modified for NaClO for MB was mainly attributed to the chemical adsorption based on the D-R model.