Effect of particle morphology on performance of an electrostatic air–liquid interface cell exposure system for nanotoxicology studies

Particle morphology can affect the performance of an electrostatic precipitator air–liquid interface (ESP-ALI) cell exposure system and the resulting cell toxicity. In this study, three types of monodisperse aerosols–spherical sucrose particles, nonspherical align soot aggregates, and nanosilver aggregates/agglomerates–were selected to evaluate the collection efficiency at flow rates ranging from 0.3 to 1.5 lpm. To quantify the particle morphology, the fractal dimensions (D_f) of the tested aerosols were characterized. The penetration of fine particles (d_p = 100–250nm) under different operating conditions was correlated with a characteristic exponential curve using the dimensionless drift velocity (V_c/V_avg,r) as the scaling parameter. For nanoparticles (NPs, d_p <100nm) with different particle morphologies, the particle penetrations in the ESP-ALI were similar, but their diffusion losses were not negligible. In contrast, for fine particles, the collection efficiency of soot nanoaggregates (D_f = 2.29) was higher than that of spherical sucrose particles. This difference might be due to the simultaneous influences of the electric field-induced and flow field-induced alignment. Furthermore, based on Zhibin and Guoquan’s Deutsch model, a quadratic equation was applied to fit the experimental data and to predict the performance of the ESP-ALI.