Dealcoholization of Beer by Osmotic Distillation for the Beverage Industry

Recently, osmotic distillation (OD) has emerged as an alternative process for the concentration and purification of heat sensitive components. However, OD performance was severely affected by membrane fouling and wetting, which could be minimized through membrane surface roughness creation and surface energy modification. This study incorporated silica nanoparticles and coated tridecafluro-1,1,2,2-tetrahydrooctyl-1-triethoxysilane at various concentration onto polyvinylidene fluoride (PVDF) membrane to improve its hydrophobicity, limiting the contact between foulants in feed solution and membrane surfaces. Generally, the addition of silica reduced the water contact angle (WCA) of the membrane, but the inclusion of silane had increased it. These membranes were then tested through OD with 1 wt% succinic acid feed solution and 50 wt% calcium chloride stripping solution. PVDF membranes that have been modified with 1 wt% silica nanoparticles and coated with 1:50 volume ratio silane solution achieved a transmembrane flux of 0.6019 kg/m<sup>2</sup>⋅h, the highest flux among silanated membrane. This was due to the larger pore size retained after silanization. A rejection rate of 95.66% and above were achieved by the membranes fabricated in this study. Overall, PVDF membrane modified with silica and silane had been successfully utilized in OD process and shown potential as a concentration and purification process.

Controlling the polymorphs of PVDF membranes: Effects of a salt additive on PVDF polarization during phase separation processes

Innovations and technology are the driving forces for new beer industry products, especially in exploring new flavor profiles. Freeze concentration (FC) emerges as an alternative to take advantage of this opportunity. This work studied the falling‐film freeze concentration (FFFC) application on ethanol–water solutions and commercial beer. The effect of flow rate, freezing temperature, and initial concentration of ethanol in the model solution was studied, and the best conditions were found with a surface response analysis and then applied to a commercial beer. The effect on the sensory profile was determined by multidimensional approximation for the lager beer and the concentrated liquid. A significant effect of initial concentration and freezing temperature were found in the ethanol–water solutions, and the best condition was found at −25°C, 400 L/h, and 0.03 w/w, with a concentration index of 1.35. This condition was evaluated for commercial beer, where a concentration index of 1.18 was achieved, caused by solids in beer and molecular interactions of ethanol with other compounds. The sensory profile of a commercial lager beer was modified by increasing the intensity in 38% of the flavor descriptors and the preservation of the other 41% after applying FFFC. The effect of this technique in beer could be a novel method to produce beer products with new flavor profiles.Practical applicationsInnovations in science and technology added to the search for new flavors promote the development of new products in the beer industry. In this article, a potential use of this freeze concentration (FC) technology was identified for the development of new concentrated beer products. The impact of falling‐film FC in a commercial lager beer was studied. First, obtaining a concentrated beer from this technique was possible, with a higher concentration of total solids and ethanol. In addition, the beer's sensory profile was modified by applying FC, which resulted in an increase in the intensity of 38% of the descriptors and the preservation of 41%. It also allowed the appearance of new flavors and aromas.

Polyvinylidene Fluoride (PVDF) has been used as a membrane’s base material for wastewater treatment for quite some time. Due to PVDF hydrophobic nature, fouling will occur, thus, reducing the membrane performance. The main objective of this study was to investigate the effect of various chitosan loadings on membrane hydrophilicity and overall liquid separation performance. The loadings of chitosan (wt.%) used were neat PVDF, 0.25%, 0.5%, 0.75% and 1% in PVDF mixed matrix membrane. It was found that 0.75% chitosan membrane had the lowest contact angle of 63° making it the most hydrophilic. The pure water flux test on the membranes also showed the same trend where the lowest contact angle resulting in the highest pure water flux. The PVDF membrane containing 0.75% chitosan possessed the highest pure water flux of 43.5 Lm−2h−1. With the rejection of dye of over 43.12%. The study proved that adding chitosan into PVDF membrane certainly improved the membrane hydrophilicity and the percentage removal of methylene blue dye.

In order to enhance the hydrophobicity of polyvinylidene fluoride (PVDF) porous membranes, the blending of PVDF with a hydrophobic ionic liquid (IL) 1-butyl-3-methylimidazolium hexafluorophosphate ([Bmim][PF6]) was carried out. The modified PVDF membranes with [Bmim][PF6] were fabricated through a non-solvent induced phase inversion using lithium chloride as a porogen in the PVDF casting solution. The effects of [Bmim][PF6] on the membrane characteristics were investigated. FT-IR analysis indicates that the IL is successfully retained by the PVDF membrane. Thermogravimetric analysis reveals that the optimum temperature of the modified membrane is below 300°C. Scanning electron microscopy pictures show that modified membranes have more homogeneous and larger diameter pores with a mean pore size of 0.521 µm and porosity of 78 %. By measuring the IL leaching during the membrane fabrication, it was found that the modified membrane does not lose IL. Atomic force microscopy shows that the roughness of the modified membrane surface increases slightly, but the contact angle of the modified membrane increases significantly from 88.1° to 110.1°. The reason for this is that the fluorine-containing IL has a low surface energy, which can enhance the hydrophobicity of the membrane. Finally, by comparing modified membranes with different IL concentrations, we draw a conclusion that the modified membrane with an IL concentration of 3 wt-% has the best properties of pore size, porosity, and hydrophobicity.

Effects of hydrogen bond donors on PVDF membrane modification using choline chloride-based deep eutectic solvents

Effect of membrane wetting on the performance of PVDF and PTFE membranes in the concentration of pomegranate juice through osmotic distillation

Comparisons of membrane fouling and separation efficiency in protein/polysaccharide cross-flow microfiltration using membranes with different morphologies

Based on the “lotus effect” principle, smooth microreliefs of polyvinylidene fluoride (PVDF) membrane were prepared via thermally induced phase separation process. Hydroxyl groups were introduced into PVDF membrane by pretreatment with KOH/alcohol solution. Subsequently, these hydroxyl groups grafted with (CH3)2SiCl2/CH3SiCl3 to form nano‐clusters, which were decorated on the microreliefs of PVDF membrane. Scanning Electronic Microscopy (SEM) and Atomic Force Microscope (AFM) analysis showed the micro‐ and nano‐scale structures, similar to lotus leaf, were successfully fabricated on the PVDF membrane surface. The water contact angle and sliding angle on the fabricated lotus‐leaf‐like PVDF membrane surface were 154 and 4°, respectively. Self‐cleaning test indicated that the lotus‐leaf‐like surface of PVDF membrane has excellent superhydrophobic and self‐cleaning properties. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Direct-coating of cellulose hydrogel on PVDF membranes with superhydrophilic and antifouling properties for high-efficiency oil/water emulsion separation

Cyclodextrin-modified PVDF membranes with improved anti-fouling performance

Ultrafiltration (UF) is widely used in water treatment to remove turbidity and pathogens; in wastewater membrane bioreactor to retain biomass; in desalination for pre-treatment of seawater. One of the main challenges during UF operation is membrane fouling which limits the potential of UF technology. The occurrence of fouling is inevitable and usually results in an increase in operational costs due to several factors such as reduced membrane lifespan, increased energy demand, and increased chemical cleaning. Many fouling control methods are available for UF operation. An example would be commercially available vibratory shear-enhanced process (VSEP), a type of unsteady-shear methods. In comparison with VSEP, piezoelectric membrane serves as the source of agitation and potentially offers lower energy consumption as an anti-fouling strategy. However, previous studies on piezoelectric membranes mainly focused on enhancing the piezoelectricity of commercial membranes through electrical poling, and the optimal operating conditions for piezoelectric membrane to improve filtration performance. It is important to extend the research to cover the fundamental understanding between membrane properties and piezoelectricity and its impact on membrane fouling, as well as the long-term application of piezoelectric membrane. In the first part of this study, piezoelectric flat sheet polyvinylidene fluoride (PVDF) membranes with different morphologies were fabricated by using different solvents via non-solvent induced phase separation (NIPS). The fabricated membranes were then electrically poled to enhance piezoelectricity and subsequently characterised in terms of morphology, piezoelectric properties, and mechanical properties. The effects of morphology on the filtration performance of piezoelectric PVDF membranes were also analysed. PVDF membranes, with finger-like morphology, had better dielectric and piezoelectric properties among all the fabricated membranes. Electrical poling aligned the dipoles of PVDF which enhanced piezoelectric properties of PVDF membranes and reduced finger-like cavities to drop-like cavities. For poled piezoelectric membranes under electrical signals, 25 to 46% significant improvement in critical flux, 66% reduction in rate of transmembrane pressure increase and approximately 3 times increase in filtration duration were observed. In the second part of this study, different quantities of piezoelectric barium titanate (BaTiO3) nanoparticles (NPs) were added during the fabrication of PVDF membranes to enhance piezoelectricity of the membranes. Some of the BaTiO3 NPs were modified by silane coupling agent to enhance dispersion and compatibility in PVDF membranes. The modified BaTiO3 NPs, particularly 0.1 wt.%, were well-dispersed in the PVDF membranes than unmodified BaTiO3 NPs, which had similar finger-like structures to neat PVDF membranes. The addition of BaTiO3 NPs to PVDF membranes improved its dielectric strength, piezoelectric coefficient, and mechanical properties. Electrical poling of the membranes further improved their piezoelectricity. A linear correlation between piezoelectric d_33 coefficient and critical flux was observed for poled piezoelectric membranes under the influence of applied electrical signals when colloidal silica was used as model foulant. In comparison with neat PVDF membranes, improvement in critical flux by up to 51% and extended duration of multiple filtration cycles by up to factor of 2 to 4 were observed for poled BaTiO3-PVDF membranes under application of electrical signals In the final part of this study, piezoelectric membrane was then implemented to filtration of real wastewater to evaluate long-term performance. The energy consumption to agitate the piezoelectric membrane through electrical AC signals and energy consumption to sustain transmembrane pressure were computed to assess the potential cost savings as compared with conventional VSEP method. The advancements of reversible, irreversible, and irremovable fouling were significantly lowered for piezoelectric membranes. The fouling pattern shifted from irremovable dominance of non-piezoelectric membrane to reversible dominance of piezoelectric membrane. The impacts of alternating current (AC) voltages and cross-flow velocities on fouling mitigation were also examined which demonstrated piezoelectric membrane under AC signals is more favourable as a fouling control strategy than increasing cross-flow due to better fouling mitigation for equivalent energy consumption. A possible synergy between piezoelectric effect and chemical cleaning was also noticed as less foulants were detected on the piezoelectric membranes at the end of the filtration cycles. The findings of this study would provide a better understanding on the fundamental relationships among membrane properties, piezoelectric properties and filtration performance and offer valuable information for the future development of piezoelectric membrane as an energy efficient anti-fouling method.

TiO2 nanoparticles with diameter of approximately 20 nm were successfully assembled on polyvinylidene fluoride (PVDF) membranes layer-by-layer so as to improve the hydrophilicity of the PVDF membranes. SEM and droplet imaging system were used to determine microstructure and hydrophilicity of PVDF membranes. The effect of the TiO2 assembling layers on the contact angle (CA) of PVDF membranes was explored. As the number of the assembling layers were 2 and 3, the CAs of the modified PVDF membranes slightly increased at initial frozen time whilst decreased obviously after 1 min. For the modified PVDF membrane with assembling 5 layers TiO2 nanoparticles, the initial CA significantly decreased to 72.1° by approximately 30%. This novel method can be used to develop high performance hydrophilic PVDF membranes with high dispersion of TiO2 in filtration and separation applications.

Polyvinylidene fluoride (PVDF) membranes represent a potential technology for the in-depth treatment of organic dye-containing wastewater. Nevertheless, the intractable membrane fouling and the limited versatility have significantly constrained its applications. Herein, through the nonsolvent-induced phase inversion method, we have successfully fabricated the PDA@MgO/PVDF and PDA@ZnO/PVDF membranes, which are modified by the synergistic action of MgO or ZnO nanoparticles with polydopamine (PDA), respectively. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), as well as the analyses of pore structure, contact angle, and surface free energy, were utilized to characterize the hybrid membranes. The results demonstrate that the modification of PDA@MgO and PDA@ZnO can enhance the hydrophilicity, pure flux, dye rejection, and pollution resistance of PVDF membranes. The enhanced hydrophilicity of the modified membranes results from the increase in surface free energy and its polar component term. Comparatively, the PDA@ZnO/PVDF membrane exhibits a smaller contact angle (69°) and a higher pure water flux (378.63 L/m2·h·bar), whereas the PDA@MgO/PVDF membrane possesses greater mechanical strength and better antifouling performance. The PDA@MgO/PVDF membrane can achieve a rejection rate of 94.6% for disperse deep blue 79, and the flux recovery rate can reach approximately 82%. This research offers novel insights into the application of PVDF membranes for the treatment of organic dye-containing wastewater.

Bio-inspired method for preparation of multiwall carbon nanotubes decorated superhydrophilic poly(vinylidene fluoride) membrane for oil/water emulsion separation