磁性Fe_3O_4/膨胀石墨对亚甲基蓝的吸附性能研究

Study on the Adsorption Property of Magnetic Fe_3O_4/Expanded Graphite for Methylene Blue

以膨胀石墨(EG)为载体,采用简单的水热法,制备出磁性Fe_3O_4/膨胀石墨(MEG)。采用X-射线衍射仪(XRD)和扫描电子显微镜(SEM)对MEG的组成结构和形貌进行表征。以亚甲基蓝为目标污染物,探讨了溶液pH值、吸附时间、盐离子浓度和亚甲基蓝初始浓度对吸附性能的影响,并对吸附动力学和吸附等温线进行研究。结果表明:当亚甲基蓝初始浓度为50 mg·L^(-1),pH值为7,吸附时间为60 min时,对亚甲基蓝的去除率和吸附量分别为97.03%和48.52 mg·g^(-1),随着溶液中盐离子Na^+和Ca^(2+)浓度的增加,MEG对亚甲基蓝的吸附性能降低;MEG对亚甲基蓝的吸附行为符合拟二级动力学模型和Langmuir等温吸附模型。MEG可以使用磁铁进行分离回收,回收率达95.71%。5次吸附-再生后,吸附量仍较高为41.72 mg·g^(-1),说明MEG吸附剂具有较稳定的重复使用能力。

Using expanded graphite （EG） as carrier, the magnetic Fe304/expanded graphite （ MEG） was prepared by hydrothermal method. The structures and morphologies of the MEG were characterized by X- ray diffraction （XRD） and Scanning electron microscope（ SEM）. Methylene Blue was used as a probe pollutant to investigate the effects of pH value, adsorption time, salt ionic strength and initial concentration on adsorption property, corresponding adsorption kinetics and adsorption isotherm were researched. The results indicate that the adsorption rate and adsorption capacity of 50 mg · L-1 methylene blue can reache 97. 03% and 48. 52 mg·g^（-1） in the condition of pH 7, absorption time 60 min ; The adsorption capacity reduces with the Na ＋ and Ca2 ＋ increase ; the adsorption behavior is mainly in accordance with the pseudo-second-order kinetics model and Langmuir model. The recovery rate can reach 97. 51% by magnet. The adsorption amount for Methylene Blue is also 41.72 mg·g^（-1） after five adsorption-regeneration cycles, which show that MEG has stable reuse ability.Key word