三维石墨烯-碳纳米管磁性气凝胶的制备及其染料吸附性能

Preparation of 3D graphene-carbon nanotube-magnetic hybrid aerogels for dye adsorption

将ZnCl_(2)、NiCl_(2)·6H_(2)O、FeCl_(2)·4H_(2)O和FeCl_(3)·6H_(2)O分别加入氧化石墨烯和碳纳米管的悬浮液中,在碱性条件下共沉淀和水中与聚乙烯醇交联后,冷冻干燥制备气凝胶。制备的气凝胶由磁性Ni_(0.5)Zn_(0.5)Fe_(2)O_(4)纳米粒子、氧化石墨烯、碳纳米管和聚乙烯醇组成,不仅具有吸附染料分子的活性位点,而且可通过外加磁场从水中分离。在最佳质量比下,制备的气凝胶对亚甲基蓝具有高的吸附容量(q_(e)=71.03 mg g^(-1))和中等磁性强度(M_(S)=3.519 emu g^(-1))。在染料浓度为0.025 mg mL^(-1)的条件下,气凝胶对亚甲基蓝、甲基橙、结晶紫及其相等质量的混合物的去除效率分别为70.1%、4.2%、8.9%和11.1%。该气凝胶重复使用3次后,再生效率仍超过82%。此外,它对生物体无毒,有望用作处理工业废水的吸附剂。

Novel hybrid aerogels were prepared by adding ZnCl_(2),NiCl_(2)·6 H_(2)O,FeCl_(2)·4 H_(2)O and FeCl_(3)·6 H_(2)O to a suspension of equal weights of graphene oxide and oxidized carbon nanotubes,followed by co-precipitation under basic conditions.The aerogels were then crosslinked with polyvinyl alcohol in water and freeze-dried.They consisted of magnetic Ni_(0.5)Zn_(0.5)Fe_(2)O_(4) nanoparticles,graphene oxide,carbon nanotubes and polyvinyl alcohol,which have active sites that attract dye molecules and could be extracted from water by applying a magnetic field.Using optimum mass ratios of ZnCl_(2)/NiCl_(2)·6 H_(2)O/FeCl_(2)·4 H_(2)O/FeCl_(3)·6 H_(2)O/(graphene oxide+oxidized carbon nanotube)at 6:6:12:12:1,the hybrid aerogel has a high adsorption capacity of 71.03 mg g^(-1) for methylene blue and a moderate magnetic strength of M_(S)=3.519 emu g^(-1).Its removal efficiencies for methylene blue,methyl orange,crystal violet and a mixture of equal masses of the three were 70.1%,4.2%,8.9% and 11.1%,respectively for the same dye concentration of 0.025 mg mL^(-1).It could be used for 3 regeneration cycles with a regeneration efficiency of over 82%.It was also not toxic to the living organisms,sugge sting that it is a promising adsorbent for treating industrial wastewater.