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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. • Aerogel modification changes filter characteristics from non-wettable to wettable. • Initial separation efficiency and pressure drop increase with thickness of aerogel layer on fibres. • Thicker aerogel layer results in longer initial and transitional stages of loading. • Thickness of aerogel structure does not affect separation efficiency in steady-state. • Oil transfer evolution across the material is described via Jump&Channel theory. [ABSTRACT FROM AUTHOR]

Abstract: Conventional MBR has been mostly based on floc sludge and the use of costly microfiltration membranes. Here, a novel aerobic granule (AG)-mesh filter MBR (MMBR) process was developed for cost-effective wastewater treatment. During 32-day continuous operation, a predominance of granules was maintained in the system, and good filtration performance was achieved at a low trans-membrane pressure (TMP) of below 0.025m. The granules showed a lower fouling propensity than sludge flocs, attributed to the formation of more porous biocake layer at mesh surface. A low-flux and low-TMP filtration favored a stable system operation. In addition, the reactor had high pollutant removal efficiencies, with a 91.4% chemical oxygen demand removal, 95.7% removal, and a low effluent turbidity of 4.1NTU at the stable stage. This AG-MMBR process offers a promising technology for low-cost and efficient treatment of wastewaters. [Copyright &y& Elsevier]

• Presence of water droplets in gas strongly influences filtration of nanoparticles. • Less efficiency and higher pressure drop during filtration in presence of droplets. • Change of filtration deposits caused by water as a reason of observed changes. • Mass trapped in filter layers depends mostly on their position, not characteristics. The dynamics of filtration efficiency during graphite nanoparticles aerosol filtration on fibrous filters was investigated. The influence of water droplets in feed gas on filtration efficiency, pressure drop as well as the form and shape of filtration deposits collected on filter was examined. Moreover, the mass distribution of collected deposits in individual layers in the case of multilayer filters was examined. We have observed that during the filtration of graphite aerosol in the presence of water droplets the observed pressure drop is significantly greater than during the filtration of sole graphite aerosol. On the other hand, the filtration efficiency is decreased in the presence of water droplets. During the filtration in multilayer filters we observed that the mass of particles deposited in upstream layer is greater than that in downstream, independently of the structure of both layers. This effect is also more significant in the presence of water droplets in feed gas. [ABSTRACT FROM AUTHOR]