Search

MIL-101 (Fe) and MIL-GO composites were successfully synthesized and used as fillers for the preparation of Pebax® 2533/PVDF thin film MMMs for CO2/N2 separation.

The fabrication of novel polyethersulfone membranes with a magnetically active surface nanolayer aiming at the reduction of concentration polarization effect and fouling phenomena is reported. Magnetic nanoparticles (MNPs) with the size smaller than 20 nm were immobilized in boundary layer of the membrane using the polyethylenimine flexible spacer. The surface properties of prepared membrane were characterized by a number of techniques: the thermogravimetric analysis (TGA), X-ray diffraction analysis (XRD), infrared spectroscopy (FTIR), scanning electron microscopy (SEM), atomic force microscopy (AFM) and Zeta potential measurements. The applicability of magnetically active membranes in ultrafiltration of different polymer solutions was revealed. The immobilization of MNPs on membrane surface allowed to increase the permeate volume flux and mass transfer coefficient due to the reduction of the concentration polarization effect.

Membrane separation technology can used to capture carbon dioxide from flue gas. However, plenty of research has been focused on the flat sheet mixed matrix membrane rather than the mixed matrix thin film hollow fiber membranes. In this work, mixed matrix thin film hollow fiber membranes were fabricated by incorporating amine functionalized UiO-66 nanoparticles into the Pebax® 2533 thin selective layer on the polypropylene (PP) hollow fiber supports via dip-coating process. The attenuated total reflection-Fourier transform infrared (ATR-FTIR), scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDX) mapping analysis, and thermal analysis (TGA-DTA) were used to characterize the synthesized UiO-66-NH2 nanoparticles. The morphology, surface chemistry, and the gas separation performance of the fabricated Pebax® 2533-UiO-66-NH2/PP mixed matrix thin film hollow fiber membranes were characterized by using SEM, ATR-FTIR, and gas permeance measurements, respectively. It was found that the surface morphology of the prepared membranes was influenced by the incorporation of UiO-66 nanoparticles. The CO2 permeance increased along with an increase of UiO-66 nanoparticles content in the prepared membranes, while the CO2/N2 ideal gas selectively firstly increased then decreased due to the aggregation of UiO-66 nanoparticles. The Pebax® 2533-UiO-66-NH2/PP mixed matrix thin film hollow fiber membranes containing 10 wt% UiO-66 nanoparticles exhibited the CO2 permeance of 26 GPU and CO2/N2 selectivity of 37.

Enzyme immobilization is a well-known method for the improvement of enzyme reusability and stability. To achieve very high effectiveness of the enzyme immobilization, not only does the method of attachment need to be optimized, but the appropriate support must be chosen. The essential necessities addressed to the support applied for enzyme immobilization can be focused on the material features as well as on the stability and resistances in certain conditions. Ceramic membranes and nanoparticles are the most widespread supports for enzyme immobilization. Hence, the immobilization of enzymes on ceramic membrane and nanoparticles are summarized and discussed. The important properties of the supports are particle size, pore structure, active surface area, volume to surface ratio, type and number of reactive available groups, as well as thermal, mechanical, and chemical stability. The modifiers and the crosslinkers are crucial to the enzyme loading amount, the chemical and physical stability, and the reusability and catalytical activity of the immobilized enzymes. Therefore, the chemical and physical methods of modification of ceramic materials are presented. The most popular and used modifiers (e.g. APTES, CPTES, VTES) as well as activating agents (GA, gelatin, EDC and/or NHS) applied to the grafting process are discussed. Moreover, functional groups of enzymes are presented and discussed since they play important roles in the enzyme immobilization via covalent bonding. The enhanced physical, chemical, and catalytical properties of immobilized enzymes are discussed revealing the positive balance between the effectiveness of the immobilization process, preservation of high enzyme activity, its good stability, and relatively low cost.

The development of thin layer on hollow-fiber substrate has drawn great attention in the gas-separation process. In this work, polydimethysiloxane (PDMS)/polyetherimide (PEI) hollow-fiber membranes were prepared by using the dip-coating method. The prepared membranes were characterized by Scanning Electron Microscope (SEM), energy-dispersive X-ray spectroscopy (EDX), and gas permeance measurements. The concentration of PDMS solution and coating time revealed an important influence on the gas permeance and the thickness of the PDMS layer. It was confirmed from the SEM and EDX results that the PDMS layer’s thickness and the atomic content of silicon in the selective layer increased with the growth in coating time and the concentration of PDMS solution. The composite hollow-fiber membrane prepared from 15 wt% PDMS solution at 10 min coating time showed the best gas-separation performance with CO2 permeance of 51 GPU and CO2/N2 ideal selectivity of 21.

The development of thin layer on hollow-fiber substrate has drawn great attention in the gas-separation process. In this work, polydimethysiloxane (PDMS)/polyetherimide (PEI) hollow-fiber membranes were prepared by using the dip-coating method. The prepared membranes were characterized by Scanning Electron Microscope (SEM), energy-dispersive X-ray spectroscopy (EDX), and gas permeance measurements. The concentration of PDMS solution and coating time revealed an important influence on the gas permeance and the thickness of the PDMS layer. It was confirmed from the SEM and EDX results that the PDMS layer’s thickness and the atomic content of silicon in the selective layer increased with the growth in coating time and the concentration of PDMS solution. The composite hollow-fiber membrane prepared from 15 wt% PDMS solution at 10 min coating time showed the best gas-separation performance with CO2 permeance of 51 GPU and CO2/N2 ideal selectivity of 21.

A highly effective method was developed to functionalize ceramic supports (Al2O3 powders and membranes) using newly synthesized spacer molecules. The functionalized materials were subsequently utilized for Candida antarctica lipase B enzyme immobilization. The objective is to systematically evaluate the impact of various spacer molecules grafted onto the alumina materials will affect both the immobilization of the enzymes and specific material surface properties, critical to enzymatic reactors performance. The enzyme loading was significantly improved for the supports modified with shorter spacer molecules, which possessed higher grafting effectiveness on the order of 90%. The specific enzyme activity was found to be much higher for samples functionalized with longer modifiers yielding excellent enantioselectivity &gt, 97%. However, the enantiomeric ratio of the immobilized lipase was slightly lower in the case of shorter spacer molecules.

International audience; According to the developed bioinspired method in the one-step procedure, the material with the petal effect was switched to lotus one. Therefore, highly hydrophobic and super-hydrophobic materials with tunable adhesive properties and fractal-like structures were successfully produced with high efficiency (67–84%). The work's essence was to modify chemically selected powders of lanthanide oxides (CeO2, Pr6O11, Nd2O3, and Gd2O3). High effectiveness of the functionalization process with 1H,1H,2H,2H-perfluorooctyltriethoxysilane (FC6) and n-octyltriethoxysilane (C6) was proven by various techniques, e.g. XPS, HR-TEM, ATR, XRD, zeta potential. Materials with water contact angle between 143.6° (CeO2-C6) and 175.5° (Nd2O3-FC6) with thermally stable nanolayer (up to 380 °C) were generated. Surfaces functionalized with FC6 possessed a polar component of surface free energy (SFE) close to zero. Water behavior in contact with the modified materials was studied, taking into consideration the unique electron structure of lanthanides assessed by goniometric measurement, also adhesion and spreading pressure were determined. Very low adhesion and polar SFE partly resulted in immediate bouncing of water droplet upon contact with the modified surface. The presented method allows preparing stable materials with a high potential in materials chemistry and modulation of surface features and engineering (e.g. heat transfer fluids, specific coating). © 2020 The Authors

Downstream processing of ABE fermentation broth is challenging issue. In this work, results of the application of both hydrophobic and hydrophilic commercial membranes during the pervaporation of ABE aqueous mixtures were investigated and presented. Hydrophobic pervaporation experiments were performed using ABE-water mixtures containing 0-5 wt% of organics in feed, using commercial membranes: POMS, PEBAX, and PervapTM4060. Separation factor and Pervaporation Separation Index were employed to discuss hydrophobic pervaporation results. PervapTM4060 membrane revealed the best separation performance in the removal of ABE components from diluted aqueous mixtures mimicking the fermentation broth, resulting in two-phase permeate containing ca. 34 wt% of organics. The subsequent liquid-liquid phase separation resulted in the organic phase containing 62 wt% of ABE. Hydrophilic pervaporation experiments were performed in contact with ABE-water system initially comprising 38 wt% of water applying both the PervapTM4100 PVA based polymeric membrane and modified silica ceramic one. Application of hydrophilic membranes allowed for the complete dewatering of ABE-water mixtures. Eventually, the combination of membrane separation processes (microfiltration, hydrophobic pervaporation, hydrophobic thermopervaporation, membrane distillation, and hydrophilic pervaporation) enhanced by the liquid-liquid phase separation was suggested for the recovery and dehydration of ABE aqueous mixture.

Pervaporation is a membrane technique used to separate azeotropic and close boiling solvents. Heterogenous PVA composite membranes with NaY zeolite supported on polyamide-6 were fabricated and utilized in organic&ndash, organic pervaporation. The efficiency of prepared membranes was evaluated in the separation of ethanol/ethyl tert-butyl ether (EtOH/ETBE) using separation factor (&beta, ) and the thickness normalized pervaporation separation index (PSIN). Implementation of the fringe projection phase-shifting method allowed to the determined contact angle corrected by roughness. The influence of the presence of water traces in the feed on the overall separation efficiency was also discussed using the enrichment factor for water (EFwater). The incorporation of NaY into PVA matrix increases surface roughness and hydrophilicity of the composite membrane. It was found that membranes selectively transport ethanol from the binary EtOH/ETBE mixture. The values of &beta, (2.3) and PSIN (288 &mu, m g m&minus, 2 h&minus, 1) for PVA-NaY/PA6 membrane were improved by 143% and 160% in comparison to the values for the pristine PVA/PA6 membrane. It was found that membranes showed EFwater &gt, 1, thus revealing the preferential transport of water molecules across membranes. These results are also significant for the design of membranes for the removal of water excess from the mixtures of organic solvents.

A novel method of polyethersulfone membrane modification with α-amylase entrapped in polymeric micelles is proposed to improve the antifouling properties of membranes. The immobilization of α-amylase is performed by its incorporation into micelles based on commercial polymeric surfactants (Tetronic®-701 and Tetronic®-90R4) with their subsequent adsorption on the membrane surface. The size of micelles loaded with enzyme depends on the nature of the surfactant and is equal to 400 and 100 nm for Tetronic®-701 and Tetronic®-90R4, respectively. Biocatalytic activity and membrane stability in the process of starch ultrafiltration are discussed in the paper. The optimal pH was found to be 6.5–7.5 for Tetronic®-701 and 6.0–6.5 for Tetronic®-90R4 micelles. The activity of enzyme entrapped in the micelles, adsorbed on the membrane surface, increased 1.5–1.8 times. The starch conversion rate of 80–90% was observed for membranes with immobilized α-amylase. The biocatalytic activity of immobilized enzyme was maintained at a high level during five cycles of regeneration. Moreover, the layer of micelles with incorporated α-amylase on the membrane surface reduced the effect of concentration polarization due to starch hydrolysis. The micelle immobilization caused hydrophilization of the surface and an increase in the number of bound water molecules which prevented the formation of a cake in the boundary layer.

A novel and efficient method is proposed to evaluate the concentration polarization (CP) effect in pervaporation process. The novelty of the method results from the approach towards the CP phenomenon, that proposes the calculation algorithm on the basis of permeate fluxes and feed/permeate compositions as a function of the feed flow velocity only. The main advantage of the method over the approaches available in the literature is that the intrinsic enrichment factor is calculated directly from the experimental data instead of being found as one of the regression parameters. To prove this approach, pervaporation experiments were carried out using commercial hydrophobic composite PDMS based membrane Pervatech for the recovery of methyl acetate (MeAc) from diluted aqueous solutions (0–1.5 wt% MeAc in feed mixture). Pervaporation performance of PDMS membrane was investigated at various feed flow rates in the range 4.8–70 dm3 h−1 and at three different temperatures of feed mixture (i.e. 30 °C, 40 °C, and 50 °C). It was shown that the intrinsic enrichment factor changes noticeably when the process parameters are altered and this change is one of the key factors affecting the concentration polarization modulus value during pervaporative removal of organic compounds from diluted aqueous solutions. With increasing temperature and feed flow rate, the concentration polarization modulus increases, reaching the value close to 1 at temperature of 50 °C and at the average feed flow rate equal to 1.34 cm s−1. Moreover, under these conditions, the thickness of the boundary layer tends to zero.

Performances of various hydrophilic and hydrophobic commercial membranes were evaluated in the pervaporative separation of binary organic-organic mixtures. The research was performed for the following binary mixtures: acetone-ethanol, ethanol-butanol, and acetone-butanol using chosen commercial membranes: DuraMem™150 (polyimide), Pervap 1060 (poly(dimethylsiloxane)) and Pervap 2216 (poly(vinyl alcohol)). For the assessment of membrane performance, in organic-organic pervaporation, transport and separation features (pervaporative separation index and separation factor) were taken into account. Regardless the membrane nature, the same component of the separated mixture was preferentially transported across the membrane. The assessment of membrane performance was additionally discussed by using Hansen's Solubility Parameters. The detailed physicochemical analyses focused on contact angle, spreading pressure and surface free energy with their components calculation were performed. The established physicochemical parameters were in a good accordance with the observed changes during pervaporative separation of organic-organic mixtures. Furthermore, an investigation of traces of water presence in feed of organic-organic mixtures on the membrane performance was discussed.

A strategy for the bioconjugation of the enzyme Candida antarctica lipase B onto titania ceramic membranes with varied pore sizes (15, 50, 150, and 300 kDa) was successfully performed. The relationship between the membrane morphology, i.e.,the pore size of the ceramic support, and bioconjugation performance was considered. Owing to the dimension of the enzyme (~33 kDa), the morphology of the ceramics allowed (50, 150, and 300 kDa) or did not allow (15 kDa) the entrance of the enzyme molecules into the porous structure. Such a strategy made it possible to better understand the changes in the material (morphology) and physicochemical features (wettability, adhesiveness, and surface charge) of the samples, which were systematically examined. The silane functionalization and enzyme immobilization were accomplished via the covalent route. The samples were characterized after each stage of the modification, which was very informative from the material point of view. As a consequence of the modification, significant changes in the contact angle, roughness, adhesion, and zeta potential were observed. For instance, for the 50 kDa membrane, the contact angle increased from 29.1 ± 1.5° for the pristine sample to 72.3 ± 1.5° after silane attachment; subsequently, it was reduced to 57.2 ± 1.5° after the enzyme immobilization. Finally, the contact angle of the bioconjugated membrane used in the enzymatic process rose to 92.9 ± 1.5°. By roughness (Sq) controlling, the following amendments were noticed: for the pristine 50 kDa membrane, Sq = 1.87 ± 0.21 µm; after silanization, Sq = 2.33 ± 0.30 µm; after enzyme immobilization, Sq = 2.74 ± 0.26 µm; and eventually, after the enzymatic process, Sq = 2.37 ± 0.27 µm. The adhesion work of the 50 kDa samples was equal to 136.41 ± 2.20 mN m−1 (pristine membrane), 94.93 ± 2.00 mN m−1 (with silane), 112.24 ± 1.90 mN m−1 (with silane and enzyme), and finally, 69.12 ± 1.40 mN m−1 (after the enzymatic process). The materials and physicochemical features changed substantially, particularly after the application of the membrane in the enzymatic process. Moreover, the impact of ceramic material morphology on the zeta potential value is here presented for the first time. With an increase in the ceramic support cut-off, the amount of immobilized lipase rose, but the specific productivity was higher for membranes possessing smaller pores, owing to the higher grafting density. For the enzymatic process, two modes of accomplishment were selected, i.e., stirred-tank and cross-flow. The latter method was characterized by a much higher effectiveness, with a resulting productivity equal to 99.7 and 60.3 µmol h−1 for the 300 and 15 kD membranes, respectively.

The recent progress in the development of membrane materials expands the applications and requirements for new, more stable, and highly effective separation materials. One of the most interesting research directions is related to membranes containing metal–organic frameworks (MOFs), and covalent organic frameworks (COFs) either in the membrane matrix or inside the membrane surface. The addition of these (macro)molecules makes it possible to tune first material properties and resistance and then transport and separation features, finally improving the membrane performance significantly. This article aims to: i) review the structure and characterization of different MOFs and COFs; ii) present the experimental protocols of MOF- or/and -COFs containing membranes formation, and iii) discuss their applications in terms of liquid separation. The important and representative studies in each field will be comprehensively revised and debated for perspectives, to await use as a reference for scientists working in associated areas. In the end, a summary and future perspectives on the utilization of MOF-/COF-containing membranes, including also niche applications, will be presented.

Hybrid separation materials intended for the hydrophobic pervaporation process with a new type of fillers were generated. Membranes based on poly(ether block amide) (Peba 2533) containing two organic fillers: 4-(trifluoromethyl)-N-(pyridine-2-yl)benzamide (denoted as F1) and 4-(dimethylamino)-N-(pyridine-2-yl)benzamide (denoted as F2) were fabricated. Novel materials were systematically characterized from the material point of view and subsequently applied in the pervaporative separation of binary water-organic mixture. The correlation between the type (e.g. hydrophobicity) and amount of the filler on the membrane performance has been discussed. The pervaporation performance was assessed for ethanol/water mixture containing 5 wt% ethanol at temperatures ranging from 30 °C to 60 °C. The separation factor (β), thickness normalized total and partial permeate fluxes (Jt,N and Ji,N), and thickness normalized Pervaporation Separation Index (PSIN) were utilized for evaluation of the process. The best efficiency in recovery of ethanol from a mixture containing 5 wt% of ethanol was found for the membranes containing 2.5 wt% of F1 (membrane denoted as PF1-2.5) and 10 wt% of F2 (membrane denoted as PF2-10). The incorporation of the organic fillers improved the pervaporation performance of the PEBA membrane, regarding both permeate flux and separation factor. The highest normalized flux of 28.9 μm kg m-2h−1 and separation factor of 4.6 was achieved at 60 °C, using PF1-2.5 in contact with 5 wt% ethanol as feed.

In this study the efficiency of three various commercial membranes based on poly(octylmethyl siloxane), poly(ether-block-amide), and poly(dimethylsiloxane) polymers were investigated in pervaporative separation of acetone, butanol, and ethanol from aqueous binary solutions (0–5 wt% of organics) at 60 °C. The influence of fermentation broth microfiltration on membrane performances in pervaporative removal of ethanol was also investigated. The use of microfiltration improved the effectiveness of the removal of ethanol from the broth comparing with the unfiltered one. Molar ratios of organics to water fluxes and Pervaporative Separation Index (PSI) values were employed to discuss membranes' performance in removal of organic solvents from binary aqueous mixture. It was found that PDMS based (Pervap4060) membrane shows the best separation efficiency in all tested binary aqueous mixtures. Modelling of the process proved the feasibility of pervaporation process for the removal of acetone, butanol and ethanol from binary and quaternary aqueous mixtures.

Pervap™ 2200, 2201, 2216, 2255, and 2510 hydrophilic, PVA membranes were investigated in pervaporation of water-tetrafluoropropanol mixtures. Physicochemical properties of membranes were characterized by determining the contact angle (CA) of water and glycerol and the surface free energy (SFE). The separation and transport properties of membranes were determined during vacuum pervaporation in contact with water-TFP mixtures containing up to 22 wt.% water. It was found that all membranes were hydrophilic (CA < 90°) and the polar component of SFE was much higher than the dispersive one. The apparent activation energy for water transport was very high (Eapp = 81.3 kJ/mol), indicated that water transport is activated thermally. Pervap™ membranes were very selective during the dehydration process of TFP. In contact with the Pervap™ 2200, 2201, and 2216 permeate contained practically pure water, regardless the feed composition. The process separation index (PSI) for Pervap™ 2200 and 2216 was close to 5000 kg m−2 h−1, suggesting that both membranes can be efficiently applied in the batch pervaporation process for TFP dehydration.

Four main tasks were presented: (i) ceramic membrane functionalization (TiO2 5 kDa and 300 kDa), (ii) extended material characterization (physicochemistry and tribology) of pristine and modified ceramic samples, (iii) evaluation of chemical and mechanical stability, and finally (iv) assessment of membrane efficiency in vacuum membrane distillation applied for volatile organic compounds (VOCs) removal from water. Highly efficient molecular grafting with four types of perfluoroalkylsilanes and one nonfluorinated agent was developed. Materials with controllable tribological and physicochemical properties were achieved. The most meaningful finding is associated with the applicability of fluorinated and nonfluorinated grafting agents. The results of contact angle, hysteresis of contact angle, sliding angle, and critical surface tension as well as Young’s modulus, nanohardness, and adhesion force for grafting by these two modifiers are comparable. This provides insight into the potential applicability of enviro...

1-(1,3-diethoxy-1,3-dioxopropan-2-ylo)-3-methylimidazolium bromide (RIL1_Br), 1-(2-etoxy-2-oxoethyl)-3-methylimidazolium bromide (RIL2_Br), 1-(2-etoxy-2-oxoethyl)-3-methylimidazolium tetrafluoroborate (RIL3_BF4) ionic liquids were synthesized. Subsequently, the dense cellulose acetate propionate (CAP)-based materials containing from 9 to 28.6 wt % of these reactive ionic liquids were elaborated. Reactive ionic liquids (RILs) were immobilized in CAP as a result of the transesterification reaction. The yield of this reaction was over 90% with respect to the used RIL. The physicochemical properties of resultant films were studied using nuclear magnetic resonance (NMR), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), atomic force microscopy (AFM), and thermogravimetric analysis (TGA). The RIL incorporation influenced the morphology of films by increasing their surface roughness with the rise of RIL content. The thermal stability of CAP-based membranes was dependent on the nature of the ionic liquid. Nevertheless, it was proven that CAP films containing RILs were stable up to 120&ndash, 150 &deg, C. Transport properties were characterized by water permeation tests. It was found that the type and the amount of the ionic liquid in the CAP matrix substantially influenced the transport properties of the prepared hybrid materials.

Highly efficient PDMS based membranes with a new type of fluorinated MOF-808 were successfully prepared and used for the first time in pervaporation (PV). Two types of ligands i.e. trifluoroacetic acid (TFA) and pentafluoropropionic acid (PFPA) were used during the MOF synthesis. These ligands with slightly different size and chemical character influenced the material properties of the membranes, i.e. roughness, contact angle, surface free energy, and thermal features. Incorporation of MOFs enhanced the membrane hydrophobicity and the performance in organic-organic PV for the separation of industrially important mixtures like, ethyl acetate-EtAc and ethyl tert-butyl ether-ETBE. The filled membranes possessed much better transport and separation features than the pristine PDMS. Substantial improvement of modified membrane performance with 5 wt% MOF (normalized Pervaporation Separation Index – PSIN = 1540 µm kg m−2 h−1) was observed in relation to pristine PDMS (PSIN = 780 µm kg m−2 h−1) and commercial Pervap™4060 (PSIN = 150 µm kg m−2h−1), during the separation of ETBE/EtOH. An important added value was the study of the impact of water traces (in the range 0.1–0.3 wt%) in the feed on the membrane performance. The level of water in the permeate was dependent on the membrane material composition, i.e. the MOF loading, since the presence of hydrophobic MOF restricted the transport of water to the permeate side.

Properties of one POMS and two PDMS based (Pervatech, Pervap 4060) membranes in recovery of various organic components (acetone, butanol, ethanol, ethyl acetate) from aqueous binary mixtures (4 wt.% of organics) were determined during pervaporation at various permeate pressures (1–25 mbar). Performances of membranes were compared, finding that Pervap 4060 is the most effective membrane in all systems tested, whereas Pervatech is the least effective. Permeances of organics and water increased with an increase of pressure on the permeate side in the most of the tested binary aqueous mixtures. Selectivity of the tested membranes towards organics was improved by increase of permeate pressure. Comparing the effectiveness of membranes, it was found that it is related to the hydrophobicity of membranes expressed by surface free energy (SFE) parameter. SFE changes in the following order: Pervap 4060 > POMS > Pervatech. Membrane performances also follow this order during pervaporation.

Pervaporation separation of acetone-butanol-ethanol aqueous mixture was studied to recover butanol. Polyphenylsulfone supported polydimethylsiloxane coated membranes were developed with polyvinylpyrrolidone additive and with two fumed silica fillers; Aerosil R202, treated with polydimethylsiloxane and Aerosil R972, treated with dimethyldichlorosilane. Membranes were prepared with fillers in each layer of the membrane, in both layers and without any filler, to investigate the effect of the fillers on the membrane performance. Furthermore, the effect of the thickness of each membrane layer was investigated. An increase in PDMS layer thickness promotes separation factor and suppresses flux, while an increase in the PPSU layer thickness has an inverse effect. After pervaporation tests at various operating conditions, the best PV performance was achieved with the membranes including R972 particles in the support layer. In the concentration range of 2-5% BuOH of feed, the average separation factor increased from 7.6 to 30.6, and the average flux increased from 300 to 536 g.m-2 h-1 by the incorporation of 3% R972 silica in the support layer. The partial fluxes of the solvents obtained from PV tests followed the order: butanol > water > acetone > ethanol. The developed R972 silica filled PPSU/PDMS membranes are found to be promising for butanol recovery from binary and quaternary aqueous mixtures.

Novel heterogeneous membranes based on poly(ether block amide) and poly(dimethylsiloxane) were prepared and modified by incorporating the grafted alumina oxides into the polymer matrix. Membranes were subsequently used for separation of organic solvent mixtures (ethyl acetate/ethanol and ethyl acetate/isopropanol). There were four types of grafting compounds applied in this research: octyltriethoxysilane (C6), 1H,1H,2H,2H-perfluorooctyltriethoxysilane (FC6), tetradecyltriethoxysilane (C12), 1H,1H,2H,2H-perfluorotetradecyltriethoxysilane (FC12). The influence of incorporation of grafted alumina oxide on physicochemical, equilibrium, transport, and separation properties was investigated. Pervaporation results were assessed using thickness-normalized Pervaporation Separation Index (PSIN) and separation factor (β). Additionally, membrane performance and equilibrium properties were discussed using Hansen's Solubility Parameters. It was found that incorporation of grafted alumina oxide improved membranes performances. The best efficiency during the separation of ethyl acetate/ethanol and ethyl acetate/isopropanol mixtures was found for membranes modified by alumina oxides grafted with octyltriethoxysilane (βEtAc/EtOH = 3.9, βEtAc/IPA = 3.4) and 1H,1H,2H,2H-perfluorotetradecyltriethoxysilane (βEtAc/EtOH = 4.3, βEtAc/IPA = 3.6). Moreover, the presence of water traces (in the range 0.1–0.3 wt%) in feed and permeate was monitored and correlated to the membrane material features. It was found that the presence of water in permeate depends on the character of the membrane and the filler used. The enrichment factor of water for PDMS/(Al2O3+FC12) obtained during separation of EtAc/EtOH and EtAc/IPA was equal to 1.11 and 0.95, respectively.

PDMS based membranes were prepared using various modification approaches. Structural and surface properties of prepared membranes were investigated applying a number of instrumental techniques (AFM, FT-IR, DSC, SEM, CA). Finally, transport and separation properties of the developed membranes were determined during pervaporation (PV) experiments in contact with water and water-ethanol mixture. The results were compared with efficiency of the native and commercial PDMS based membrane. Applied preparation procedures resulted in creation of membranes possessing different morphology and pervaporative performance, e.g. modification of membrane matrix with salt method resulted in smaller crosslinking ratio of poly(dimethyl siloxane) sample comparing with pristine PDMS membrane. Whereas, plasma treatment of PDMS sample caused reduction of hydrophobic properties of PDMS membrane resulting in much lower separation factor (β = 6.0). PV results showed that PDMS_NaCl (β = 10.5) and PDMS_Al2O3_mod._C8 (β = 10.8) possessed the most selective properties towards organics among all PDMS based membranes tested in this study, showing that salt method and filling of poly(dimethylsiloxane) matrix with triethoxy(octyl)silane (C8) modified Al2O3 allowed to obtain improved membranes performance in hydrophobic pervaporation.

Hydrophilic ceramic membranes (tubular and planar) made of TiO2 and Al2O3 were efficiently modified with non-fluorinated hydrophobic grafting molecules. As a result of condensation reaction between hydroxyl groups on the membrane and reactive groups of modifiers, the hydrophobic surfaces were obtained. Ceramic materials were chemically modified using three various non-fluorinated grafting agents. In the present work, the influence of grafting time and type of grafting molecule on the modification efficiency was evaluated. The changes of physicochemical properties of obtained hydrophobic surfaces were determined by measuring the contact angle (CA), roughness (RMS), and surface free energy (SFE). The modified surfaces were characterized by contact angle in the range of 111–132°. Moreover, hydrophobic tubular membranes were utilized in air-gap membrane distillation to desalination of sodium chloride aqueous solutions. The observed permeate fluxes were in the range of 0.7–4.8 kg·m−2·h−1 for tests with pure water. The values of permeate fluxes for membranes in contact with NaCl solutions were smaller, within the range of 0.4–2.8 kg·m−2·h−1. The retention of NaCl in AGMD process using hydrophobized ceramic membranes was close to unity for all investigated membranes.