磁性氧化石墨烯制备及去除水中刚果红的研究

采用Hummer方法制备了氧化石墨烯(GO),采用化学共沉淀法把铁氧化物纳米粒子覆盖在GO上制成磁性氧化石墨烯(MGO),并把MGO用作吸附剂去除水中阴离子染料刚果红.采用扫描电镜(SEM)、透射电镜(TEM)、Zeta电位仪和磁强计对MGO进行了表征.研究了吸附动力学,吸附等温线及初始pH值,离子强度对吸附的影响.考察了MGO对自来水中刚果红的去除效果.结果表明,GO具有片状的二维纳米结构,表面有许多的褶皱;当pH3.5,吸附剂表面带负电荷,等电点为3.5;MGO的饱和磁化强度为31.2emu/g,足够从水溶液中分离出来.刚果红的吸附符合准二级动力学模型,且在吸附时间为7h内基本达到吸附平衡.在超纯水中最大吸附容量高达140.6mg/g,且吸附量随pH值升高先增加再降低,当pH4~5达到最大值.MGO对自来水中刚果红的最大吸附容量为287.6 mg/g,为在超纯水中的2倍,表明MGO对刚果红具有很好的去除效果.

Synthesis of magnetic graphene oxide adsorbent for congo red removal from aqueous solution

Graphene oxide (GO) was synthesized using Hummer’s method and magnetic graphene oxide (MGO) was prepared by coprecipitation of iron oxide nanoparticles on GO nanosheets. MGO was used as adsorbent for removing anionic dye congo red from aqueous solution and was characterized by scanning electron microscope(SEM), transmission electron microscope (TEM), Zeta SIZER and vibrating sample magnetometer(VSM). Adsorption kinetics, isotherms, the effects of initial pH and ionic strength on adsorption, and congo red removal efficiency in tap water were also investigated. Results showed that GO exhibited layered 2D nanostructure with many wrinkles on the surface. The surface charge was positive at pH3.5, the pH PZC value of MGO was 3.5. The saturation magnetization of MGO adsorbent was 31.2emu/g, which was sufficient to separate from aqueous solution. The sorption processes coincided with the pseudo-second-order kinetic model and the adsorption equilibrium was reached within 7 h. The maximum adsorption capacity reached up to 140.6 mg/g in ultrapure water. Adsorption quantity first increased and then decreased gradually with increasing pH value, and reached the maximum at pH 4~5.The adsorption capacity for congo red in tap water was 287.6 mg/g, which was two times of that in ultrapure water, indicating that MGO was effective in removing congo red and had the potential in the application of congo red removal in real wastewater treatment.