The development of a renewable absorbent with a high adsorption efficiency is of great importance for the purification of dye wastewater. A nitrogen-doped graphene aerogel (N-GA) was prepared by a one-step hydrothermal and freeze-drying method using polyvinyl alcohol (PVA) as a cross-linking agent. Results indicated that the nitrogen doping provided more adsorption sites for the dyes. The PVA-N-GA showed excellent adsorption efficiencies for methylene blue (MB) (98.39% at pH=8) and methyl orange (MO) (78.78% at pH=2). The adsorption kinetic data of MB and MO on the PVA-N-GA were better fitted with a pseudo-second-order kinetic model than a pseudo-first-order kinetic model while the adsorption isotherms of MB and MO were better described by the monolayer Langmuir model and the multilayer Freundlich model, respectively. The PVA-N-GA showed excellent recycling stability with a negligible decay of adsorption efficiency after five cycles, which was ascribed to PVA making the three-dimensional (3D) pore structure of the N-GA more stable. The adsorption of the PVA-N-GA for dyes was mainly attributed to the π-π bonds, hydrogen bonds and electrostatic interactions.

具有高吸附效率的可再生吸收剂的开发对于染料废水的净化非常重要。使用聚乙烯醇（PVA）作为交联剂，通过一步水热冷冻干燥法制备了氮掺杂石墨烯气凝胶（N-GA）。结果表明，氮掺杂为染料提供了更多的吸附位。PVA-N-GA对亚甲基蓝（MB）（pH = 8时为98.39％）和甲基橙（MO）（pH = 2时为78.78％）表现出优异的吸附效率。MB和MO在PVA-N-GA上的吸附动力学数据比拟一阶动力学模型更适合拟二阶动力学模型，而MB和MO的吸附等温线可通过单层更好地描述Langmuir模型和多层Freundlich模型。PVA-N-GA在五个循环后显示出极好的循环稳定性，而吸附效率几乎没有下降，这归因于PVA，从而使N-GA的三维（3D）孔结构更加稳定。PVA-N-GA对染料的吸附主要归因于π-π键，氢键和静电相互作用。