芒草基木质纳米纤维素气凝胶的制备及其对罗丹明B吸附性能的研究

Preparation of Miscanthus-based Lignocellulosic Nanofibrils Aerogel and Its Adsorption Property Towards Rhodamine B

中文关键词:  芒草  木质纳米纤维素  气凝胶  罗丹明B  吸附机理

Key Words:Miscanthus  lignocellulosic nanofibrils  aerogel  Rhodamine B  adsorption mechanism

中文摘要:

      以芒草秸秆为原料，采用柠檬酸预处理结合高压均质，制得木质纳米纤维素（LCNF），并经冷冻干燥得到LCNF气凝胶，研究了LCNF气凝胶对阳离子染料罗丹明B（RB）的吸附性能和吸附机理。结果表明，在中性条件下，LCNF气凝胶对RB的吸附效果最佳，温度为55 ℃时，平衡吸附量增至40.0 mg/g。吸附动力学和热力学研究表明，LCNF气凝胶对RB的吸附过程符合准二级吸附动力学模型，以化学吸附为主导，且吸附过程是自发进行的；吸附过程中LCNF与RB间存在氢键、静电等相互作用。LCNF气凝胶具有良好的可重复使用性，循环使用4次后，RB去除率仍保持在83%以上。

Abstract:

      Lignocellulosic nanofibrils （LCNF） was prepared from Miscanthus using citric acid pretreatment combined with high-pressure homogenization， and LCNF aerogel was obtained after freeze-drying. The adsorption performance and mechanism of the aerogel towards cationic dye Rhodamine B （RB） was investigated. The results showed that the adsorption capacity towards RB by LCNF aerogel was the best under neutral conditions， and the equilibrium adsorption capacity increased to 40.0 mg/g at 55 ℃. The adsorption kinetics and thermodynamics studies showed that the adsorption towards RB by LCNF aerogel conformed to the pseudo-second-order kinetic model， which was mainly dominated by chemical adsorption and spontaneous. There were some interactions such as hydrogen bonding and electrostatic attraction between LCNF and RB during the adsorption process. In addition， LCNF aerogel showed good reusability and the removal rate of RB remained above 83% after four cycles.