Abstract

Currently, the use of membrane techniques has undergone dynamic growth, particularly due to the diversification of their fields of application. This trend is expected to increase owing to new environmental protection requirements and thanks to the increasingly competitive energy and technical-economic performances offered by membrane processes. New research is constantly being carried out to better understand the functioning of membranes, to create more efficient or more specific membranes, and also to develop processes for new applications. The aim of this work is to improve the performance of a polyamide reverse osmosis membrane by chemical modification of its surface. Thin film polyamide reverse osmosis membranes are widely used for desalination. However, these membranes face a fouling issue that results in low permeation flux, which is undesirable in the reverse osmosis process. An interesting alternative to improve the properties of these polyamide composite membranes is the use of chemical surface modification. In this context, we studied the chemical grafting of vinyl acetate monomer on the surface of a polyamide membrane in order to improve the selectivity towards sodium ion. The chemical grafting was carried out by radical polymerization of vinyl acetate monomer in the presence of benzoil peroxide as an initiator in an organic medium. Unmodified, modified membranes and evolution of the polymerization reaction were analyzed by Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), interferometric electron microscopy, and contact angle. An application with a front filtration module was investigated to confirm the improved selectivity for sea water. This study revealed an improved efficiency of the reverse osmosis PA membrane after the grafting of polyacetate monomer on the active layer of this membrane.

中文翻译：

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乙烯基单体表面接枝对聚酰胺薄膜复合膜的化学改性

摘要

目前，膜技术的使用经历了动态增长，特别是由于其应用领域的多样化。由于新的环境保护要求以及膜工艺提供的日益具有竞争力的能源和技术经济性能，预计这一趋势将会增加。新的研究不断进行，以更好地了解膜的功能，创造更高效或更具体的膜，并开发新应用的工艺。这项工作的目的是通过对其表面进行化学改性来提高聚酰胺反渗透膜的性能。薄膜聚酰胺反渗透膜广泛用于海水淡化。然而，这些膜面临着导致低渗透通量的结垢问题，这在反渗透过程中是不希望的。改善这些聚酰胺复合膜性能的一个有趣的替代方法是使用化学表面改性。在此背景下，我们研究了醋酸乙烯酯单体在聚酰胺膜表面的化学接枝，以提高对钠离子的选择性。化学接枝通过乙酸乙烯酯单体在有机介质中以过氧化苯甲酰作为引发剂的自由基聚合进行。通过傅里叶变换红外光谱 (FTIR)、扫描电子显微镜 (SEM)、干涉电子显微镜和接触角分析未改性、改性膜和聚合反应的演变。研究了带有前置过滤模块的应用，以确认提高了对海水的选择性。这项研究揭示了在该膜的活性层上接枝聚乙酸酯单体后，反渗透 PA 膜的效率有所提高。