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Niu, Z., Bian, Y., Xia, T., Zhang, Li.*, Chen, C.* (2021). An optimization approach for fabricating electrospun nanofiber air filters with minimized pressure drop for indoor PM2.5 control. Building and Environment, 188, 107449. (Particle filtration, PM2.5, Building)

Electrospun nanofiber air filters can achieve remarkable particle filtration efficiency with low pressure drop. Therefore, they can potentially be installed in buildings for reducing indoor PM2.5 concentrations. To improve filtration performance, this study developed a design and fabrication approach for electrospun nanofiber air filters with minimized pressure drop under a target PM2.5 filtration efficiency. First, this research developed semi-empirical models for calculating the pressure drop and PM2.5 filtration efficiency of nylon electrospun nanofiber filters using the fabrication parameters of electrospinning time and nylon concentration. With the developed models, this investigation then proposed an optimization approach to minimize the pressure drop under a given PM2.5 filtration efficiency and air velocity. For a given air velocity and PM2.5 filtration efficiency, one can minimize the pressure drop by finding the optimal solution concentration, while the target PM2.5 filtration efficiency can be achieved through adjustment of the electrospinning time. Furthermore, the proposed optimization approach successfully minimized the pressure drop for 110 out of the 125 cases, with an average pressure drop reduction of 32.7%. Finally, this research numerically studied the performance of a window screen coated with the optimized nanofiber filter in reducing indoor PM2.5 of outdoor origin

Xia, T., Chen, C.* (2021). Evolution of pressure drop across electrospun nanofiber filters clogged by solid particles and its influence on indoor particulate air pollution control. Journal of Hazardous Materials, 402, 123479. (Particle filtration, PM2.5, Building)

Because of the relatively low pressure drop and high particle removal efficiency, nanofiber filter media can be potentially used for indoor particulate air pollution control. However, the influence of particle loading on the long-term performance of nanofiber filters in indoor particle control has not been well studied. This study first experimentally investigated the relationship between the pressure drop and solid particle loading mass for 42 nanofiber filter samples under various face velocities. The results show that the air resistance coefficient increased with the solid particle loading mass for the nanofiber filter media. Furthermore, the air resistance coefficient was positively associated with the face velocity, as a higher air velocity tended to make the particle cake tighter with higher resistance. Based on the experimental data, a semi-empirical equation was developed for predicting the pressure drop under different particle loading masses and face velocities. The developed semi-empirical model was then used to assess the long-term performance of an air cleaner equipped with nanofiber filter media in indoor PM2.5 control. The case study demonstrated that an air cleaner equipped with nanofiber filter media could effectively control indoor PM2.5, but the lifetime of the nanofiber filter was shorter than that of traditional HEPA filters

2020 Particle