Abstract Due to the special properties of electrospun nanofibers such as high surface area and porosity, ease of surface functionalization, low pressure drop, suitable mechanical strength, their application in the fabrication of air purifying filtration media has increased dramatically in the recent years. The release of nanomaterials from electrospun nanofibers and human exposure to these substances is one of the concerns regarding to application of nanofiber media in air purifying applications. The aims of present study were to fabricate and characterize the nanofiber filter media, and to determine the release of nanomaterials from them during their application in a filter test rig for removing potassium chloride (KCl) nanoparticles. Polyacrylonitrile, one of the most commonly used polymers in electrospun nanofiber filter media, was embedded with various nanomaterials including magnesium oxide nanoparticles and single wall carbon nanotube and was converted to nanofiber filter mats via electrospinning process. The air samples were collected at the downstream of prepared nanofiber filter mats using polycarbonate (PC) and mixed cellulose ester (MCE) filters according to NIOSH methods 7404 and 7402. The PC filters were analyzed by FE-SEM microscopy for assessing potential release of nanofibers and MCE filters were analyzed by CytoViva's Hyper Spectral Imaging System coupled with Enhanced Dark Field Microscopy (HIS-EDFM) for assessing the potential release of nanomaterials (SWNTs and MgO NPs) from the electrospun nanofiber filter mats. The findings indicated that electrospun nanofibers and their embedded nanoparticles were rarely detached and released from the filter media during normal filtration process. Therefore, it is possible to obtain a very low release by improving quality of the nanofiber filter media and applying a safe design approach.

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评估电纺纳米纤维过滤介质中纳米材料的潜在释放

摘要 由于电纺纳米纤维具有高表面积和孔隙率、易于表面功能化、压降低、机械强度合适等特殊性能，近年来它们在空气净化过滤介质制造中的应用急剧增加。从电纺纳米纤维中释放纳米材料和人体接触这些物质是纳米纤维介质在空气净化应用中应用的关注点之一。本研究的目的是制造和表征纳米纤维过滤介质，并确定纳米材料在用于去除氯化钾 (KCl) 纳米颗粒的过滤器试验台中的应用过程中从中释放的纳米材料。聚丙烯腈是电纺纳米纤维过滤介质中最常用的聚合物之一，嵌入了各种纳米材料，包括氧化镁纳米颗粒和单壁碳纳米管，并通过静电纺丝工艺转化为纳米纤维过滤垫。根据 NIOSH 方法 7404 和 7402，使用聚碳酸酯 (PC) 和混合纤维素酯 (MCE) 过滤器在制备的纳米纤维过滤垫的下游收集空气样品。通过 FE-SEM 显微镜分析 PC 过滤器以评估纳米纤维的潜在释放和 MCE 过滤器通过 CytoViva 的高光谱成像系统结合增强暗场显微镜 (HIS-EDFM) 进行分析，以评估纳米材料（SWNT 和 MgO NPs）从电纺纳米纤维过滤垫中的潜在释放。研究结果表明，在正常过滤过程中，电纺纳米纤维及其嵌入的纳米颗粒很少从过滤介质中分离和释放。因此，通过提高纳米纤维过滤介质的质量和应用安全的设计方法，可以获得非常低的释放量。