PDA/RGO复合材料对水中Fe(Ⅲ)的吸附行为

摘要

将多巴胺与氧化石墨烯纳米片层接枝复合制备了聚多巴胺/还原氧化石墨烯(PDA/RGO)复合材料,通过XRD、FTIR、FESEM和XPS等对该复合材料的结构和表面性质进行表征,并研究了其对水中Fe(Ⅲ)的吸附性能,考察了pH、吸附剂用量、吸附时间、Fe(Ⅲ)浓度和温度对其吸附性能的影响.结果表明:通过多巴胺与氧化石墨烯的仿生复合成功制备出具有优良吸附性能的PDA/RGO复合材料.pH为2,293 K时,该吸附材料对水中Fe(Ⅲ)的最大吸附量为59.1 mg·g-1,其吸附等温线符合Freundlich方程,吸附动力学可用准二级动力学方程来描述.吸附热力学研究表明该复合材料对Fe(Ⅲ)的吸附过程为自发吸热过程,呈现非均质吸附特性.作为一种新型吸附材料,该复合材料在Fe(Ⅲ)等金属污染废水处理中将具有潜在的应用前景.%The bio-inspired polydopamine/reduced graphene oxide (PDA/RGO) composites were prepared by grafting dopamine with graphene oxide nanosheets. The structure and surface properties of the as-synthesized composites were characterized by X-ray diffraction (XRD), Fourier-transformed infrared spectroscopy (FTIR), field-emission scanning electron microscopy (FESEM) and X-ray photoelectron spectroscopy (XPS). The adsorption behavior and properties of aqueous Fe(Ⅲ) on the PDA/RGO composites were also investigated. The effects of pH, adsorbent amounts, adsorption time, initial concentration of Fe(Ⅲ) and temperature on adsorption properties were investigated in details. From these characterization results, it was indicated that dopamine and graphene oxide could be successfully produced to PDA/RGO compositesvia the bio-inspired self-assembly. The PDA/RGO composites showed high adsorption performance for aqueous Fe(Ⅲ). The maximum adsorption capacity of 59.1 mg·g-1 for Fe(Ⅲ) on the PDA/RGO composites was obtained at 293 K and pH of 2. The adsorption isotherm of Fe(Ⅲ) on the PDA/RGO composites could be described better with Freundlich equation model than Langmuir model, and the pseudo-second-order kinetics equation fitted well with the adsorption data. The adsorption process for Fe(Ⅲ) on the PDA/RGO composites was an exothermic and spontaneous, exhibiting heterogeneous adsorption characteristics. As a kind of new adsorption materials, the PDA/RGO composites will have potential application in wastewater treatment containing metals such as Fe(Ⅲ).