Innovation in air filtration devices using advanced salt recrystallization techniques

带电过滤器广泛应用于空气过滤设备和空气污染物的个人防护措施。然而，过滤纤维的电荷衰减和疏水性引起了人们对其抗生物气溶胶性能的担忧。因此，过滤器上捕获的细菌等生物污染物可以存活很多天，由于交叉感染、新的气溶胶释放和受污染的废物，对公共安全构成直接威胁。因此，开发一种创新的机制来提高现有过滤设备对抗生物气溶胶的性能并将这一概念应用于制造能够迅速灭活细菌的新的过滤设备是至关重要的。 我们的目标是开发一种简单而高效的抗菌过滤装置，利用聚丙烯(PP)纤维和盐重结晶现象。盐涂层空气过滤器的设计不仅可以防止生物气溶胶的传播，而且可以物理地摧毁它们。具体地说，当携带细菌的气溶胶与过滤纤维接触时，盐涂层溶解，然后随着气溶胶的蒸发，盐重结晶。这会通过抗原的变性和/或脂膜的破坏而使细菌失活。在这个项目中，我们将主要致力于盐涂层PP过滤器的设计、开发和性能测试。通过用生理盐水配方浸泡或喷洒PP过滤器，然后干燥，将形成盐涂层。不同的盐浓度和干燥方法可以控制包覆盐晶体的厚度和形貌。盐涂层将进行优化，以满足不同应用的具体要求。例如，不同的盐类型和表面活性剂将分别提高在不同湿度条件和底物类型下的稳定性。我们将通过测量压降、过滤效率、随时间变化的传染性变化、菌株非特异性、环境稳定性和可重用性来评估原型空气过滤器的性能，以符合监管机构的标准。 该计划的技术成果将推进保护加拿大人和世界免受生物气溶胶侵害的总体战略。这反过来将通过将研究成果扩展到专门从事个人/公共保护措施(即机舱空气和暖通空调过滤器、口罩和呼吸器)的行业，并促进向行业合作伙伴转让技术，从而为加拿大经济做出贡献。最终，该计划将导致在先进材料科学、过滤器制造/表面改性技术和生物技术方面对高素质人员进行多学科培训，并将加拿大带入针对细菌污染的高效空气过滤设备的全球研究的前沿。

Electrically charged filters are widely used in air filtration devices and personal protective measures against airborne contaminants. However, electrical charge decay and hydrophobic nature of the filter fibers raise a concern over their performance against bioaerosols. As a result, the biological contaminants such as bacteria captured on filters can survive for many days, posing an immediate danger to public safety due to cross-infection, new aerosol release, and contaminated waste. Therefore, it is critical to develop an innovative mechanism to increase the performance of existing filtration devices against bioaerosols and apply the concept to fabricate new filtration devices capable of inactivating bacteria swiftly. We aim to develop a simple yet efficient antibacterial filter device, utilizing polypropylene (PP) fibers and salt recrystallization phenomenon. Salt-coated air filters can be designed not only to prevent transmission of bioaerosols but to physically destroy them. Specifically, when the bacteria-laden aerosols make contact with the filter fibers, the salt coating dissolves and then salt recrystallizes as aerosols evaporate. This causes inactivation of the bacteria through denaturation of antigens and/or destruction of lipid envelopes. In this program, we will be primarily dedicated to the design, development, and performance testing of the salt-coated PP filters. A salt coating will be formed by soaking or spraying the PP filters with a saline formulation, followed by drying. The thickness and morphology of the coated salt crystals will be controlled by varying salt concentration and drying method. The salt coating will be optimized to meet diverse application-specific requirements. For example, stability at different humidity conditions and substrate types will be improved by varying salt types and surfactants, respectively. We will evaluate the performance of the prototype air filters against regulatory agency standards by measuring pressure drop, filtration efficiency, time-dependent infectivity change, strain non-specificity, environmental stability, and reusability. The technological outcomes of this program will advance the general strategy to protect the Canadians and the world against bioaerosols. This in turn will contribute to the Canadian economy by expanding research outcomes to the industries specializing in personal/public protective measures (i.e. cabin air and HVAC filters, facial masks, and respirators), and promoting technology transfer to industrial partners. Ultimately, this program will lead to the multidisciplinary training of highly qualified personnel in advanced materials science, filter fabrication/surface modification techniques, and biotechnology, and bring Canada to the forefront of the universal search of an efficient air filtration device against bacterial pollution.