Tiago Gonçalo, Cristóvão Maria Beatriz, Marques Ana Paula, Huertas Rosa, Merino-Garcia Ivan, Pereira Vanessa Jorge, Crespo João Goulão, Velizarov Svetlozar
LAQV-REQUIMTE, Department of Chemistry, NOVA School of Science and Technology, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal.
IBET-Instituto de Biologia Experimental e Tecnológica, Apartado 12, 2780-901 Oeiras, Portugal.
Membranes (Basel). 2022 Jul 8;12(7):697. doi: 10.3390/membranes12070697.
This study covers the modification, (bio)fouling characterization, use, and cleaning of commercial heterogeneous anion exchange membranes (AEMs) to evaluate their feasibility for reverse electrodialysis (RED) applications. A surface modification with poly (acrylic) acid resulted in an improved monovalent perm-selectivity (decreased sulfate membrane transport rate). Moreover, we evaluated the (bio)fouling potential of the membrane using sodium dodecyl sulfate (SDS), sodium dodecyl benzenesulfonate (SDBS), and Aeromonas hydrophila as model organic foulants and a biofoulant, respectively. A detailed characterization of the AEMs (water contact angle, ion exchange capacity (IEC), scanning electron microscopy (SEM), cyclic voltammetry (CV), and Fourier Transform Infrared (FTIR) spectra) was carried out, verifying that the presence of such foulants reduces IEC and the maximum current obtained by CV. However, only SDS and SDBS affected the contact angle values. Cleaning of the biofouled membranes using a sodium hypochlorite aqueous solution allows for (partially) recovering their initial properties. Furthermore, this work includes a fouling characterization using real surface and sea water matrixes, confirming the presence of several types of fouling microorganisms in natural streams. A lower adhesion of microorganisms (measured in terms of total bacteria counts) was observed for the modified membranes compared to the unmodified ones. Finally, we propose a cleaning strategy to mitigate biofouling in AEMs that could be easily applied in RED systems for an enhanced long-term process performance.
本研究涵盖了商用异相阴离子交换膜（AEMs）的改性、（生物）污垢表征、使用和清洗，以评估其在反向电渗析（RED）应用中的可行性。用聚丙烯酸进行表面改性可提高单价离子选择透过性（降低硫酸盐膜传输速率）。此外，我们分别使用十二烷基硫酸钠（SDS）、十二烷基苯磺酸钠（SDBS）和嗜水气单胞菌作为模型有机污垢剂和生物污垢剂，评估了膜的（生物）污垢潜力。对AEMs进行了详细表征（水接触角、离子交换容量（IEC）、扫描电子显微镜（SEM）、循环伏安法（CV）和傅里叶变换红外（FTIR）光谱），证实这些污垢剂的存在会降低IEC和CV获得的最大电流。然而，只有SDS和SDBS影响接触角值。使用次氯酸钠水溶液清洗生物污染的膜可（部分）恢复其初始性能。此外，这项工作还包括使用真实表面和海水基质进行污垢表征，证实在天然水流中存在几种类型的污垢微生物。与未改性的膜相比，改性膜上观察到微生物的附着力较低（以总细菌数衡量）。最后，我们提出了一种减轻AEMs中生物污垢的清洗策略，该策略可轻松应用于RED系统，以提高长期工艺性能。
