Rafi Mohammad, Samiey Babak, Cheng Chil-Hung
Department of Chemistry, Faculty of Science, Lorestan University, Khoramabad 68137-17133, Lorestan, Iran.
Department of Chemical Engineering, Ryerson University, Toronto, ON M5B 2K3, Canada.
Materials (Basel). 2018 Mar 26;11(4):496. doi: 10.3390/ma11040496.
Graphene oxide/poly(amidoamine) (GO/PAMAM) nanocomposite adsorbed high quantities of congo red (CR) anionic dye in 0.1 M NaCl solution, with the maximum adsorption capacity of 198 mg·g. The kinetics and thermodynamics of adsorption were investigated to elucidate the effects of pH, temperature, shaking rate, ionic strength, and contact time. Kinetic data were analyzed by the KASRA model and the KASRA, ISO, and pore-diffusion equations. Adsorption adsorption isotherms were studied by the ARIAN model and the Henry, Langmuir, and Temkin equations. It was shown that adsorption sites of GO/PAMAM at experimental conditions were phenolic hydroxyl groups of GO sheets and terminal amine groups of PAMAM dendrimer. Analysis of kinetic data indicated that amine sites were located on the surface, and that hydroxyl sites were placed in the pores of adsorbent. CR molecules interacted with the adsorption sites via hydrogen bonds. The molecules were adsorbed firstly on the amine sites, and then on the internal hydroxyl sites. Adsorption kinetic parameters indicated that the interaction of CR to the -NH₃⁺ sites was the rate-controlling step of adsorption of CR on this site and adsorption activation energies calculated for different parts of this step. On the other hand, kinetic parameters showed that the intraparticle diffusion was the rate-controlling step during the interaction of CR molecules to -OH sites and activation energy of this step was not calculable. Finally, the used GO/PAMAM was completely regenerated by using ethylenediamine.
氧化石墨烯/聚酰胺胺（GO/PAMAM）纳米复合材料在0.1 M NaCl溶液中吸附了大量刚果红（CR）阴离子染料，最大吸附容量为198 mg·g。研究了吸附的动力学和热力学，以阐明pH值、温度、振荡速率、离子强度和接触时间的影响。动力学数据通过KASRA模型以及KASRA、ISO和孔扩散方程进行分析。吸附等温线通过ARIAN模型以及亨利、朗缪尔和坦金方程进行研究。结果表明，在实验条件下，GO/PAMAM的吸附位点是氧化石墨烯片层的酚羟基和聚酰胺胺树枝状大分子的末端胺基。动力学数据分析表明，胺位点位于表面，而羟基位点位于吸附剂的孔中。CR分子通过氢键与吸附位点相互作用。分子首先吸附在胺位点上，然后吸附在内侧羟基位点上。吸附动力学参数表明，CR与-NH₃⁺位点的相互作用是CR在该位点吸附的速率控制步骤，并计算了该步骤不同部分的吸附活化能。另一方面，动力学参数表明，颗粒内扩散是CR分子与-OH位点相互作用期间的速率控制步骤，且该步骤的活化能无法计算。最后，使用乙二胺可使所用的GO/PAMAM完全再生。
