还原氧化石墨烯高效吸附双酚F的机理研究

Study on Mechanism of Highly Effective Adsorption of Bisphenol F by Reduced Graphene Oxide

本研究关注了还原氧化石墨烯(RGO)对内分泌干扰物双酚F(BPF)的高效吸附机理。与同类碳基吸附剂材料GP和GO相比,RGO显示出作为一种高效吸附剂用于去除废水中BPF的巨大潜力。Freundlich模型能够较好地拟合BPF在RGO表面的吸附等温线,这说明BPF在RGO表面可能发生了多层吸附。热力学研究结果表明,BPF在RGO表面吸附是一个自发的吸热过程。溶液pH值从2.0增加到11.0,RGO对BPF的吸附最开始缓慢增加,pH值超过BPF的pKa1后,吸附容量增加到最大值。BPF发生二次解离后,由于静电排斥作用较强,导致其与RGO的结合作用减弱,从而使吸附效率急剧减小。RGO高效吸附BPF的主要机理为π-π相互作用、疏水作用和静电辅助氢键作用,由于溶液pH值不同,导致各种作用的强弱不同,从而使RGO的吸附能力也存在显著差异。本研究为RGO这类石墨烯碳基吸附剂用于去除水环境中具有可解离性的内分泌干扰物提供了理论依据。

The mechanism of highly efficient adsorption of endocrine disruptor bisphenol F(BPF)by reduced graphene oxide(RGO)was investigated in this study.Compared with similar carbonaceous adsorbents(such as GP and GO),RGO exhibit great potential as an efficient adsorbent for removing BPF from waste water.The adsorption isotherm of BPF on the surface of RGO can be well fitted by Freundlich model,which indicated the occurrence of multilayer adsorption of BPF on RGO surface.The results of thermodynamic studies showed that the adsorption of BPF on RGO surface was a spontaneous endothermic process.The adsorption capacity of RGO to BPF increased slowly with the increase of solution pH value from 2.0 to 11.0.After pH exceeded the pKa1 of BPF,there was a rapid raise in the adsorption capacity and interaction affinity until the maximum was achieved.Once the secondary dissociation of BPF occurred,the adsorption capacity and affinity of RGO decreased dramatically,due to the strong electrostatic repulsion.The primary mechanism of highly efficient adsorption of BPF by RGO includedπ-πinteraction,hydrophobic interaction and charge-assisted hydrogen bonding.The different pH value of the solution could lead to significant difference in adsorption capacity of RGO to BPF.This study provided a theoretical basis for the new graphene-based adsorbents used for removing dissociable endocrine disruptors in contaminated water.