He Haoyang, Chen Qian, Fu Rongqiang, Liu Zhaoming, Ge Liang, Xu Tongwen
Key Laboratory of Precision and Intelligent Chemistry, School of Chemistry and Materials Science, University of Science and Technology of China, Hefei, 230026, China.
Applied Engineering Technology Research Center for Functional Membranes, Institute of Advanced Technology, University of Science and Technology of China, Hefei, 230088, China.
Chem Bio Eng. 2024 Jul 10;1(7):647-657. doi: 10.1021/cbe.4c00096. eCollection 2024 Aug 22.
Electrodialysis (ED) technology for waste acid treatment has high economic efficiency and environmentally friendly advantages. The primary limitation of ED in the retrieval of low-concentration spent acids lies in the leakage of hydrogen ions through anion exchange membranes (AEMs) due to its extremely small size and high mobility. To address this issue, a series of AEMs named QPAB- ( = 3, 5, 7, 10) were designed for acid concentration in ED process by increasing the membrane densities through in situ crosslinking in this study. The successful synthesis of polymers was confirmed through H nuclear magnetic resonance hydrogen (H NMR) spectroscopy and Attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy. Furthermore, ATR-FTIR spectroscopy showed that the higher the side chain content, the higher the crosslinking degree of the membranes. X-ray photoelectron spectroscopy (XPS) was employed to characterize the effects of aqueous and acidic environments on QPAB membranes. The performance disparities between QPAB- membranes in acidic and aqueous environments were examined separately. Subsequently, the influence of crosslinking degree on the acid-blocking capability of the membranes was thoroughly investigated by conducting ED acid-concentration experiments to monitor the hydrogen ions concentration process and determine the current efficiency and energy consumption of the QPAB- membranes. Our experimental results demonstrated that QPAB- membranes with higher cross-linking degrees have lower water content, especially the QPAB-10 membrane with an IEC of approximately 1.5 mmol g and a remarkably low water content of around 10%. This leads to a reduced H transfer number and excellent acid-blocking properties. Additionally, compared to commercial membrane A2, using the QPAB-10 membrane in the ED process resulted in a higher final H concentration in the concentrated chamber. Consequently, these synthesized membranes exhibit considerable promise in the field of ED acid recovery.
用于废酸处理的电渗析（ED）技术具有高经济效率和环境友好的优势。ED在回收低浓度废酸方面的主要限制在于氢离子由于其极小的尺寸和高迁移率而通过阴离子交换膜（AEM）泄漏。为了解决这个问题，本研究通过原位交联提高膜密度，设计了一系列名为QPAB-（ = 3、5、7、10）的AEM用于ED过程中的酸浓缩。通过氢核磁共振氢谱（H NMR）和衰减全反射傅里叶变换红外光谱（ATR-FTIR）证实了聚合物的成功合成。此外，ATR-FTIR光谱表明侧链含量越高，膜的交联度越高。采用X射线光电子能谱（XPS）表征水性和酸性环境对QPAB膜的影响。分别考察了QPAB-膜在酸性和水性环境中的性能差异。随后，通过进行ED酸浓缩实验来监测氢离子浓度过程并确定QPAB-膜的电流效率和能耗，深入研究了交联度对膜的阻酸能力的影响。我们的实验结果表明，交联度较高 的QPAB-膜含水量较低，特别是IEC约为1.5 mmol g且含水量极低约为10%的QPAB-10膜。这导致H迁移数降低和优异的阻酸性能。此外，与商业膜A2相比，在ED过程中使用QPAB-10膜导致浓缩室中最终H浓度更高。因此，这些合成膜在ED酸回收领域展现出可观的前景。
