改性氧化石墨烯对水中亚甲基蓝的吸附特性

Adsorption of methylene blue in water by modified graphene oxide

为了解决氧化石墨烯(GO)吸附污染物后难以从水溶液中分离的问题,采用聚乙烯亚胺(PEI)对GO进行改性,制备PEI-GO复合材料,并采用红外光谱仪、拉曼、扫描电镜和能谱仪等对复合材料进行结构和形貌表征。分析不同吸附时间、吸附剂用量对亚甲基蓝(MB)吸附性能的影响,并对其采用动力学及温线模型进行拟合,记录GO吸附MB与PEI-GO吸附MB后从溶液中的分离时间。结果表明,PEI-GO复合材料具有良好的二维纳米结构,纳米片层中的含氧官能团与PEI中的氨基反应生成O=C-NH共价键。复合材料PEI-GO对MB具有良好的吸附性能。在MB初始质量浓度为25 mg/L,PEI-GO投入量为30 mg的条件下,PEI-GO的吸附量可达204.87 mg/g;吸附规律符合准二级动力学模型以及Freundlich等温模型;吸附后,分离速率较GO吸附后快4~5倍。

In order to solve the problem that it is difficult to separate graphene oxide(GO)from aqueous solution after adsorption of pollutants,PEI-GO composite was prepared by modifying GO with PEI,and the structure and morphology of the composite was characterized by FT-IR,Raman,SEM and EDS.The effects of different adsorption time and adsorbent dosage on the adsorption performance of MB were analyzed,and the kinetic and temperature line models were used to fit them.The separation time of MB adsorbed by GO and PEI-GO was recorded respectively.The results show that PEI-GO composite still has a good two-dimensional nanostructure and the O=C-NH covalent bond which is formed by the reaction of the oxygen-containing functional group in the nano film and the amino group in PEI.The composite PEI-GO has good adsorption property for MB.When the initial concentration of MB is 25 mg/L and the input amount of PEI-GO is 30 mg,the adsorption capacity of PEI-GO can reach 204.87 mg/g.The adsorption behavior conformed to quasi second-order kinetic model and Freundlich isothermal model.After adsorption,compared with GO adsorption,the separation rate is 4-5 times faster.