1. Water flow decrease of track-etched polyethylene terephthalate membranesAna Ambrož, Zhen Yao, Christopher Rojas, Polina Angelova, Armin Gölzhäuser, Irena Petrinić, 2025, original scientific article Abstract: Track-etched polyethylene terephthalate (TE-PET) membranes, characterized by their well-defined cylindrical pores and narrow pore size distribution, offer advantages in filtration applications but demonstrate a gradual decrease of water flux over time. In this work, we evaluate the performance of track-etched polyethylene terephthalate (TE-PET) membranes as microfilters in low-pressure cross-flow and dead-end filtration systems. Membranes with pore sizes between 0.2 and 2.5 μm and porosities of 0.2–20% were tested at different low pressures (0.02–10 bar). Monitoring water flux over time exhibited a significant reduction. This behaviour is attributed to polymer swelling within the pore walls due to the formation of a sol-gel film. Notably, this swelling is enhanced under dynamic flow conditions, with larger pores exhibiting more rapid and pronounced flux decline. When filtering organic solvents, the flux drop is less pronounced and depends on their viscosity and polarity. Surface characterization by atomic force microscopy further confirmed morphological changes in TE-PET support after water filtration. Additional contributing factors, such as fouling and compaction, are also discussed.
Keywords: track-etched support, polyethylene terephthalate, water filtration, swelling, sol-gel film, carbon nanomembrane
Published in DKUM: 13.06.2025; Views: 0; Downloads: 5
 Full text (5,62 MB) |
2. Energy intake models for intermittent operation of dead-end microfiltration filling lineJure Ravnik, Gorazd Bombek, Aleš Hribernik, Timi Gomboc, Matej Zadravec, Aleks Kapun, Grega Hrovat, Jure Gradišek, Matjaž Hriberšek, 2022, original scientific article Abstract: In filling lines equipped with membrane separation devices in the form of filters energy,
consumption is only one of the important working parameters, the other being sustainable filter
performance in terms of separation efficiency. As the filling line is typically equipped with a valve,
intermittent operation of the filter is an important form of its use. Whereas the overall energy
consumption of the filtration process is governed by the continuous operation mode, the intermittent
mode, characterised by opening/closing of the valve, contributes most to problems of filter failure,
i.e., the breakthrough of filtered particles through the membrane. A model for determination of the
energy intake of a microfiltration membrane during the opening and closing of a valve is presented
in this work. The model is based on computational analysis of the pressure wave signals recorded
during the opening/closing of the valve using Fourier transform, and expressed in a nondimensional
filter area specific energy intake form. The model is applied to a case of constant pressure dead-end
microfiltration with three filter types: a single membrane filter, a stacked filter and a pleated filter
with filtration surface areas ranging from 17.7 cm2
to 2000 cm2. Both clean filters, as well as partially clogged filter cases are taken into account. Second order polynomial models of the energy intake are developed and evaluated based on extensive analysis of the experimental data. The analysis of energy intake results show that the largest energy intake was observed for the clean filter case. When membrane fouling occurs at the constant flow rate values it leads to larger energy intake, however,
due to a decreasing specific flow rate during fouling these values do not exceed the clean filter case.
Keywords: membrane filtration, water hammer effect, membrane energy intake, filter clogging
Published in DKUM: 28.03.2025; Views: 0; Downloads: 2
Full text (4,01 MB)
This document has many files! More... |
