•Surface patterning of polymer membranes can be an effective strategy to improve the device performances.•Both porous and dense membranes can be patterned via templated-based micro-molding and direct ...printing methods.•Patterned membrane-electrode assembly can enlarge the active surface area and form more effective ion conduction pathways.•Presence of surface pattern can enhance the shear at the porous membrane surface during separation, which can benefit fouling mitigation.
In recent years, surface patterning of membranes has been explored as a new strategy to modify surface properties of polymeric membranes. A variety of methods including template-based micromolding and direct printing have been developed for effective fabrication of surface-patterned membranes. In this review, we compare the underlying pattern replication mechanisms and the advantages and challenges associated with the range of different fabrication methods. The presence of the surface patterns, when properly created, can enlarge the active surface/interfacial area, create more effective conduction pathways, and enhance the hydrodynamic effects. These effects can be harnessed for improving membrane performance for a wide range of applications.
Sustainability integration in project portfolio management helps shape strategic, organizational, and project-based contexts. The authors conducted a structured literature review from 2000 to 2021 ...and developed a novel integrative framework presenting a holistic view highlighting three substantive research themes: sustainability mindset, sustainability assessment, and sustainability integration in project portfolio processes. Noteworthy progress has been made at the strategic and portfolio levels toward framing a sustainability mindset (definition, values, and principles) and developing frameworks/tools for sustainability assessment and project portfolio selection. However, areas for more research include integrating sustainability into project portfolio processes, reporting, and organizational learning for portfolio improvement.
Surface roughness of membranes is often perceived by many as a factor that promotes fouling during filtration, and thus is undesirable. Almost all liquid-based separation membranes display flat ...surfaces with an intrinsic surface roughness that is associated with the membrane manufacturing process. Recently, polymer ultrafiltration and thin film composite membranes containing regular, periodic surface patterns were fabricated using cost-effective lithographic methods. Here, we review the work to date on the fabrication and characterization of these patterned membranes with a focus on processing-structure-performance relationships. In addition, the antifouling performance of these membranes against model foulants including colloidal suspensions and protein solutions is also highlighted.
In the present study, different metals included Ni and Cu were separately loaded on the mixed matrix of Al
2
O
3
-TiO
2
to be used in catalytic-oxidative-adsorptive desulfurization of liquid ...hydrocarbon model fuel. The prepared catalysts were characterized by X-ray diffraction (XRD), N
2
adsorption–desorption and field emission scanning electron microscopy (FE-SEM). The effects of different important parameters on catalytic-adsorptive desulfurization in the presence of hydrogen peroxide including sulfur/catalyst ratio (mg g
−1
) in the range of 4–12, oxidant/sulfur molar ratio (mol mol
−1
) of 4–10, temperature in the range of 30 °C–70 °C, and reaction time of 30–90 min. for the model fuel of n-decane with 800 ppm dibenzothiophene were investigated. Response surface methodology was used to design of experiments and explore the synergistic effects of investigated parameters. The results showed that Ni/Al
2
O
3
-TiO
2
has higher sulfur removal efficiency than Cu/Al
2
O
3
-TiO
2
. Maximum efficiency (83.9%) was achieved when Ni/Al
2
O
3
-TiO
2
was used at the conditions included sulfur to catalyst ratio = 4 mg g
−1
, oxidant to sulfur molar ratio = 10 mol mol
−1
, temperature = 70 °C, and the reaction time = 90 min. It was found that the efficiency of desulfurization for catalysts was increased with decreasing of the sulfur to catalyst ratio and increased when oxidant to sulfur molar ratio, temperature and reaction time increased.
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In this study, bilayer mixed matrix membranes based polyether block amide containing ZIF-8 metal organic nanoparticles, as dispersed particles within the polymer matrix, were synthesized to separate ...carbon dioxide from methane. To prevent nanocomposite membrane selectivity from a drastic reduction at high loading, the particles were modified by APTMS, APTES. The modified nanoparticles were identified and examined using XRD, BET, DLS, and FTIR. Then the permeability tests were performed with carbon dioxide and methane. A 40 μm thick PES membrane was produced as the base and the PEBA/ZIF-8 MMM with the thickness of about 4 μm as the thin, selectively permeable layer. The APTES-modified ZIF-8 nanoparticles increased forces between the particle surface and polymer chains leading to increased permeability without any significant change in the selectivity. At the loading of 40 wt percentage, the permeability of carbon dioxide significantly improved to 6.7 × 10−8 molm−2s−1pa−1 and selectivity remained about 16.
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•The PES/PEBAX/ZIF-8 bilayer mixed matrix membranes modified by two silane coupling agents were synthesized.•The particles and membranes were studied by XRD, BET, SEM, DLS and FTIR and Permeation of gases were evaluated.•The MMM based polyether block amide containing ZIF-8-APTES showed a promising performance in CO2/CH4 Separation.
The presence of surface patterns on separation membranes, when properly designed, can enhance the membrane performance by increasing the active surface area, tuning the surface wettability, and ...promoting mass transfer in the boundary layer. This work reports a new method of patterning microporous membranes, namely, lithographically templated thermally induced phase separation (lt-TIPS). Templated by surface-patterned elastomeric molds, the TIPS of poly (vinylidene fluoride) (PVDF) and tributyl O-acetylcitrate (ATBC) lead to successful pattern replication onto the PVDF membranes. We systematically examined the TIPS processing conditions, including PVDF/ATBC concentration (20 wt%, 25 wt% and 30 wt%) and quenching temperature (25 °C and 100 °C), on the fidelity of pattern replication, as well as structure and properties of the PVDF membranes. Experimental results show that lower solution concentration and direct quenching to 25 °C lead to higher fidelity of pattern replication. Lower concentration and higher quenching temperature result in membranes with larger pores and higher porosity. In comparison with non-patterned PVDF membranes, the patterned PVDF membranes display similar pore structures, mechanical characteristics and crystallinity. In contrast, the presence of the surface pattern significantly increases the water contact angle and pure water flux, as expected from the increase in active surface area. The work shows that lt-TIPS is an effective method for patterning membranes, complementary to existing imprinting and phase-inversion based methods.
•A new method is shown to pattern membranes by combining thermally induced phase separation and soft lithography.•PVDF membranes were patterned with this method under varying concentration and quenching depth.•Patterning fidelity of this method is between 0.5 and 0.7•Patterned membranes display enhanced hydrophobicity and pure water flux, compared with control membranes.
The permeation resistance of the porous support in a thin film composite (TFC) membrane is believed to be negligible compared with that of the thin polyamide film. Indeed, the resistance of a porous ...support, as determined from direct water permeation experiments as a function of transmembrane pressure (TMP), is only a fraction of the total resistance of a typical TFC membrane. However, the true resistance of the porous support in a TFC membrane, especially during high-pressure reverse osmosis (RO), could be significantly different from the value obtained via direct permeation measurement. Although the porous support is subjected to mechanical loading equivalent to the overall TMP, the effective TMP across the porous support that generates deformation can be significantly lower due to the internal pressure of the water within the pores. In this study we utilized a serial configuration, consisting of a TFC membrane on top of a representative porous support, to quantify the true resistance of the porous support under conditions of high mechanical loading but low permeation. Unsurprisingly, the results confirm that the porous support resistance appears negligible as compared with that of the TFC membrane under low TMP. However, after exposure to high TMP in the serial configuration, the porous support evidences up to 15X larger plastic strain and 28X higher resistance as compared to the same support tested separately under low TMP. At TMP = 8.3 MPa, the additional porous support beneath the TFC membrane increases the overall resistance by 31%. Using a resistance in-series model, the data suggest that the true resistance of the porous support could be as high as ~ 45% that of the thin film under the high-TMP but low-permeation condition encountered during high-pressure RO desalination.
•A serial configuration is used to determine the true permeation resistance of the porous support under RO condition.•The plastic strain of the porous support under the serial configuration is determined.•The porous support experience significantly more deformation under RO condition than under direct permeation measurements.•True resistance of the porous support is significant for a TFC membrane under high-pressure RO.
This work investigates the convective heat transfer enhancement of water-based nanofluids in pipe heat exchanger used for the ethanol condensation process. The nanofluids were produced with different ...nature of nanoparticles, Cu, Fe3O4, MWCNT, and graphene, in the volume concentration 0.01–0.1%, using different surfactants. These nanoparticles are characterized by X-ray powder diffraction (XRD), Scanning electron microscopy (SEM), specific surface area (BET), and Dynamic light scattering (DLS). Density, thermal conductivity, and viscosity of base fluids and nanofluids were experimentally determined at a relevant temperature of 20 °C. Convective heat transfer enhancement under laminar regime was evaluated from a well-designed experimental setup. As the main results, the thermal conductivity of nanofluids increases up to 3–5% and the viscosity can increase or decrease with nanoparticle concentration, showing a lubricating effect of nanoparticles coupled with respective surfactant. It was shown that the heat transfer properties, heat transfer coefficient, and Nusselt number, are increased with nanofluids compared to water and base-fluids, up to 20%, in the range of Pe 2000–10000. Experimental heat transfer properties are shown to be greater than theoretical ones. Finally, copper nanofluid at low concentration appear to be the best candidate for the application and pipe flow geometry considered.
Water-based nanofluids for heat transfer enhancement Display omitted
•Heat transfer of water-based nanofluids during ethanol process condensation.•Characterization of Cu, Fe3O4, MWCNT and graphene nanoparticles.•Impact of surfactant, nanoparticle nature and content on nanofluid heat transfer.•Density, thermal conductivity and viscosity experimental evaluation.•Comparison between theoretical heat transfer properties and experimental data.
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