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Particulate matter poses a serious threat to human health. In particular, exposure to submicron particles can result in more severe health effects as they can deposit more deeply into human tissues. Metal–organic framework (MOF)-based nanofiber filters are regarded as promising candidates for efficient particle control. In this study, ZIF-8@PAN nanofiber filters that were developed via an in situ growth strategy were selected for the filtration of submicron particles. The addition of ZIF-8 more effectively enhanced the filtration of particles with smaller sizes. For the most penetrating particle size of around 0.3 μm, the MOF-based nanofiber filter exhibited an 8.9% increase in filtration efficiency compared with that of the pure nanofiber filter. Meanwhile, for particles with large aerodynamic diameters (in the range of 0.7–1 μm, for example), the role of ZIF-8 was negligible. This work provides important insights into the filtration performance of MOF-based nanofiber filters in capturing submicron particles and may aid in designing nanofiber filters for efficient control of particles.

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In this paper, a simple nonlinear constitutive model for piezoelectric ceramics is devised. The model is implemented in a research finite element code and used to study the effect of domain switching and electric nonlinearity on the cracking behaviour. J-integrals are computed along contours close to and well away from the crack tip. For linear materials, the computed J-integrals are essentially path independent. With the material non-linearity considered, the integrals computed at the crack tip vicinity is higher than the ones computed well away from the crack tip. Using the former as the fracture criterion, it is found that crack propagation can be promoted by the electric field.