厚度依赖CO2吸附聚乙烯胺薄膜用于直接捕获空气
John R Hoffman1, Avery E Baumann1, Christopher M Stafford1
1Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, MD, 20899, United States.
Chemical engineering journal (Lausanne, Switzerland : 1996)
|March 21, 2024
概括
在二氧化上的聚乙烯胺 (PEI) 是有效的二氧化碳捕获. 最佳的PEI薄膜厚度 (50纳米) 平衡了直接捕获空气的容量和效率,改进了吸附剂设计.
科学领域:
- 材料科学 材料科学 材料科学
- 化学工程是化学工程的重要组成部分.
- 环境科学 环境科学
背景情况:
- 用聚乙烯胺 (PEI) 浸的半孔是一种有前途的材料,用于直接捕获CO2的空气 (DAC).
- 诸如二氧化碳度,温度和氨基荷载等因素通过影响扩散和反应动力学来影响捕获能力和效率.
- 在3D吸附剂材料中的内部扩散使在空气/胺基界面上的反应动力学的分析变得复杂.
研究的目的:
- 在2D几何学中研究基于PEI的氨基层的CO2吸附动力学.
- 了解薄膜厚度,温度和二氧化碳度对二氧化碳捕获的影响.
- 为了确定CO2吸附在空气/胺基接口的最佳条件.
主要方法:
- 设计了一种结合石英晶体微平衡与散射 (QCM-D) 和偏振调制红外反射吸收光谱 (PM-IRRAS) 的新型双重仪器.
- 研究了PEI薄膜 (10-100纳米厚) 在不同温度 (25-80°C) 和CO2度 (0.04%和5%) 的二氧化碳吸附动力学.
- 适应了伪第一顺序和Avrami分数顺序模型的吸附配置文件.
主要成果:
- 随着薄膜厚度的增加,二氧化碳捕获能力增加,但由于扩散限制,氨基效率下降.
- 厚薄膜 (>50 nm) 被氨基可用性限制,而薄薄膜 (<50 nm) 被CO2可用性限制.
- 一个50纳米的PEI薄膜表现出最佳的性能,可以捕获0.04%的CO2. 反应机制从扩散受限转变为根据二氧化碳度在特定温度下动力受限.
结论:
- 在PEI薄膜的空气/氨基接口上实现了CO2吸附的准确分析.
- 结果提供了关于二氧化碳捕获中扩散和动力学之间的相互作用的见解.
- 这些发现可以指导用于直接捕获空气应用的改进吸附材料的设计.
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