造粒的氮掺杂碳纳米管基吸附剂对卤水中硼的吸附行为与机理

Adsorption behavior and Mechanism of nitrogen-doped carbon Nanotube-based adsorbents for Boron in Brine

中文关键词:  盐湖卤水  吸附法  碳纳米管  硼  聚丙烯腈

英文关键词:Salt lake brine  Adsorption  Carbon nanotubes  Boron  Polyacrylonitrile

中文摘要:

      盐湖卤水中的硼的资源丰富，存在形式复杂多样，分离和回收硼的意义重大。基于N掺杂强静电与多羟基协同作用能够有效提高硼阴离子的分离机制，设计以水合肼为N源，多羟基的一维纳米材料碳纳米管（CNTs）为多羟基络合基，采用简单的一锅水热法合成了N掺杂的碳纳米管硼吸附材料（N-CNTs）。此外，以改性的聚丙烯腈为造粒剂，经造粒后，最大硼吸附容量为20.45 mg/g，特别在低浓度硼的分离中表现出优异的性能，这使N-CNTs成为硼的高效吸附材料。吸附机理为一维碳纳米管和改性聚丙烯腈高比表面积上多羟基与N掺杂位置强静电协同增强络合吸附。硼吸附过程符合朗格缪尔吸附等温模型和准二阶动力学模型，在高浓盐多离子溶液中表现出优异的选择性硼吸附性能。该吸附剂在东台吉乃尔盐湖卤水中硼的吸附容量达18.92±1 mg/g，提出的该简单技术在盐湖卤水及水处理行业具有较高的应用潜力。

英文摘要:

      Boron in salt lake brine is rich in resources and exists in complex and diverse forms, so it is of great significance to separate and recover boron. N doping can effectively improve the separation mechanism of boron anions by the synergistic effect of strong electrostatic and polyhydroxy groups on the surface of the material. N-doped carbon nanotube boron adsorption materials (N-CNTs) were synthesized by a simple one-pot hydrothermal method using hydrazine hydrate as N source and one-dimensional carbon nanotubes (CNTs) as polyhydroxyl groups. In addition, using modified polyacrylonitrile as granulator, the maximum boron adsorption capacity is 20.45 mg/g, especially in the separation of low concentration boron, which makes N-CNTs the best adsorption material for boron. The adsorption mechanism is that polyhydroxyl groups and N-doped sites on the high specific surface area of one-dimensional carbon nanotubes and modified polyacrylonitrile are enhanced by strong electrostatic coordination adsorption. The process of boron adsorption accords with Langmuir adsorption isothermal model and Second-order kinetic model, which shows excellent selective boron adsorption performance in high concentration salt multi-ion solution. The adsorption capacity of boron in East Taigener salt lake brine is 18.92 ±1 mg/g. The proposed simple technology has high application potential in salt lake brine and water treatment industry.