Electret filter media are electrostatically charged nonwovens which are commonly used for separation of fine particles from gases. The separation behavior of the unloaded filter media has been extensively investigated in the past for a variety of filter media and particles using experiments and simulations. Moreover, the phenomenom of filter ageing of filter ageing by particle deposition and possible causes for that are well known, but to what extent these individual effects contribute to the ageing is still unclear. Thus, the aim of this work is to investigate the dominant effects causing filter ageing by means of experiments and simulations.

The experiments revealed a decreasing filtration efficiency with increasing exposure to sodium chloride particles. A detailed consideration of the particle size and charge distribution indicated that charge neutralization is the dominant effect for filter ageing in this case. The implementation of this interaction between particle and fiber charge in a numerical simulation tool showed a good agreement in the decrease of the filtration efficiency with the experimental findings.

驻极体过滤介质是带静电的非织造材料，通常用于从气体中分离细颗粒。过去，已使用实验和模拟对各种过滤介质和颗粒物进行了广泛研究，研究了卸载的过滤介质的分离行为。此外，由于颗粒沉积而引起的过滤器老化的过滤器老化现象及其可能的原因是众所周知的，但是这些个体效应在多大程度上有助于老化的原因尚不清楚。因此，这项工作的目的是通过实验和模拟研究导致过滤器老化的主要影响。

实验表明，随着氯化钠颗粒暴露量的增加，过滤效率降低。对粒度和电荷分布的详细考虑表明，在这种情况下，电荷中和是过滤器老化的主要影响。在数值模拟工具中实现颗粒与纤维电荷之间的这种相互作用，表明过滤效率的降低与实验结果吻合得很好。