羧甲基纤维素-石墨烯复合气凝胶的制备及吸附研究

Preparation and adsorption of carboxymethylcellulose graphene composite aerogels

在氧化石墨的基础上添加适量廉价的羧甲基纤维素,以一步水热反应成功制备羧甲基纤维素/石墨烯复合气凝胶(CMC/GA),并对CMC/GA进行官能团结构、微观形貌等表征分析。以水中亚甲基蓝(MB)为吸附对象,研究CMC/GA对水中MB的吸附能力和吸附机制。结果表明:温度越高,MB溶液的初始浓度越大,对吸附越有利;吸附等温线符合Langmuir模型,吸附体系的活化能为57.951 kJ·mol-1,表明CMC/GA对MB的吸附为单分子层吸附且属于化学吸附。MB的吸附动力学符合准二级动力学模型;内扩散模型表明,CMC/GA对不同浓度MB的吸附过程均分为大孔扩散和微孔扩散两个阶段且大孔扩散速率明显大于微孔扩散。

Cellulose graphene composite aerogels(CMC/GA)were prepared by one-step hydrothermal reaction based on graphite oxidation with the addition of low cost carboxymethyl cellulose.The functional group structure and microstructure of CMC/GA were characterized.The mechanism and capacity of the adsorption of Methylene Blue(MB)were investigated by CMC/GA in water.The results show that the higher temperature and higher initial concentration of MB are beneficial to the adsorption of CMC/GA.The adsorption isotherm is fitted with Langmuir model,the adsorption activation energy of the systemis57.951 kJ·mol^-1,indicating that the adsorption of MB by CMC/GA is monolayer and belongs to chemical adsorption.The adsorption kinetics of MB is fitted with pseudo-second order kinetics model.The intrapartical diffusion model of MB with different concentration shows that the adsorption process of CMC/GA for MB can be divided into two stages:macroporous diffusion and microporous diffusion,and the diffusion rate of macroporous diffusion is obviously higher than that of microporous diffusion.