三维石墨烯气凝胶的制备及对罗丹明B的吸附性能

Preparation of 3D graphene aerogel and its adsorption properties on Rhodamine B

以氧化石墨烯(GO)为原料,亚硫酸氢钠为还原剂,采用较温和的化学还原法将GO还原成石墨烯,并通过冷冻干燥技术制备具有三维立体结构的石墨烯气凝胶(GA),探究其对罗丹明B(RhB)染料溶液吸附性能的影响;并对吸附平衡、吸附动力学和吸附机理进行研究。结果表明:GA对RhB染料的吸附性较好,吸附剂投加量、RhB溶液初始质量浓度以及吸附时间等因素均对吸附性能有影响;吸附过程符合准二级动力学模型和Langmuir等温线模型,表明GA对RhB染料的吸附反应是化学吸附,且呈单分子层吸附。颗粒内扩散模型分析表明,GA对RhB染料的吸附过程中内部扩散是吸附速率的控制步骤,但不是唯一的速率控制步骤,吸附机理较为复杂。

The 3D graphene aerogels （GA） are prepared via mild chemical reduction method together with freezing-drying technique by using graphene oxide （GO） as the raw material and sodium bisulfite （NaHSO3） as reductant. The factors affecting the adsorption properties of GA on Rhodamine B （RhB） dye solution are investigated, and the adsorption equilibrium, adsorption kinetics as well as adsorption mech- anism are studied. The results show that GA has good adsorption capacity on RhB dye, and the adsorp- tion capacity is affected by the amount of adsorbent, the initial concentration of RhB solution and the ad- sorption time. The adsorption process is in accordance with pseudo-second order kinetic model and Langmuir isotherm model, indicating that the adsorption reaction of GA on RhB dye is chemical adsorp- tion and presented in monolayer adsorption mode. Besides, the intraparticle diffusion model analysis shows that the internal diffusion is the rate controlling step of the adsorption process, but it is not the only rate controlling step, indicating a complicated adsorption mechanism of GA on RhB.