An effect of fibrous filters modification with MTMS aerogel structure on oil mist filtration dynamics

Various modifications are utilized to improve the oil mist separation efficiency of non-woven filters. Our previous work proposed an oleophilisation method involving coating polypropylene filter fibres with porous organosilica aerogel based on methyltrimetoxysilane (MTMS). The filters with fibers with collector area enhanced by this modification exhibited even three times higher initial separation efficiency for oil mists than the native polymer filters. In order to determine the effect of the amount of aerogel layer deposited on polypropylene fibers it is required to investigate the dynamics of filtration of these filters modified with the sol-gel technique over the whole time of use of the filters. This article describes the aerogel deposition influence on the total efficiency of filters over time, efficiency changes for the most penetrating droplets (MPPS), the evolution of pressure drop and oil transport across the material. The results show that the thicker aerogel layer on fibres results in higher initial separation efficiency and pressure drop, simultaneously elongating an initial and transitional loading stage. Filter performance in steady-state seems unaffected by the amount of deposited aerogel. Also, modification with aerogel makes the filter fibres more oleophilic, which translates into changes in filter behaviour described via Jump&Channel theory.