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Article

Sustainable Novel Membranes Based on Carboxymethyl Cellulose Modified with ZIF-8 for Isopropanol/Water Pervaporation Separation

by
Anna Kuzminova
1,*,
Mariia Dmitrenko
1,
Roman Dubovenko
1,
Anna Mikulan
1,
Anastasia Stepanova
1,
Margarita Puzikova
1,
Nadezhda Rakovskaya
1,
Anton Mazur
1,
Anna Shurukhina
1,
Aida Rudakova
1,
Alexei Emeline
1,
Rongxin Su
2 and
Anastasia Penkova
1,*
1
St. Petersburg State University, 7/9 Universitetskaya nab., St. Petersburg 199034, Russia
2
State Key Laboratory of Chemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
*
Authors to whom correspondence should be addressed.
Sustainability 2025, 17(9), 3801; https://doi.org/10.3390/su17093801
Submission received: 17 March 2025 / Revised: 4 April 2025 / Accepted: 20 April 2025 / Published: 23 April 2025
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Abstract

:
The present study investigates the potential of novel mixed matrix membranes that are formed from the biopolymer carboxymethyl cellulose (CMC) and the metal–organic framework ZIF-8 to improve the pervaporation dehydration of isopropanol. The effect of ZIF-8 content variation and porous substrate selection (comprising cellulose acetate (CA) and polyacrylonitrile) on dense and supported membrane properties is systematically investigated using multiple analytical techniques. It is found that ZIF-8 incorporation alters the membrane structure (confirmed by FTIR and NMR), increases surface roughness (observed via SEM and AFM), enhances swelling degree (obtained by swelling measurements), improves surface hydrophobicity (determined by contact angle analysis), and elevates thermal stability (verified by TGA). Quantum chemical calculations are used to validate the interactions between the polymer matrix, modifier, and feed components. The transport properties of developed membranes are evaluated through the dehydration of isopropanol via pervaporation. The cross-linked supported CMC membrane with 10 wt% ZIF-8 prepared on the CA substrate has the optimal performance: permeation flux of 0.136–1.968 kg/(m2h) and ˃92 wt% water in the permeate via the dehydration of isopropanol (water content 12–100 wt%) at 22 °C.

Graphical Abstract

1. Introduction

Modern society increasingly prioritizes sustainable processes that balance human needs with environmental preservation. As demands for substance quality, purity, and environmental friendliness grow, energy-efficient methods, advanced materials, and effective purification technologies are gaining prominence [1,2]. Membrane technologies align well with these sustainability goals, offering cost-effectiveness, environmental friendliness, minimal reagent use, and ease of operation compared to traditional separation techniques [3,4]. The creation of new highly efficient membrane materials is a pressing task. The selection of polymer–modifier combinations is critically important in the development of mixed matrix membranes (MMMs), as it significantly influences transport characteristics, allowing for the overcoming of the trade-off limitation between selectivity and permeability, thereby achieving high performance to meet the demands of real-world industrial applications [5]. Currently, metal–organic frameworks (MOFs), which feature advantages such as a high surface area, rich chemical functionality, and tunable pore structures, represent a promising class for the fabrication of MMMs. The characteristics of these membranes depend not only on the nature of the filler but also on various macroscopic properties, including pore architecture, surface features, and the particle size distribution of the filler material [6]. Due to their unique properties, MOFs have recently found wide application as modifiers for the creation of MMMs for pervaporation [7,8], ultrafiltration [9,10], gas separation [11,12,13], and nanofiltration [14,15]. These porous coordination polymers consist of three-dimensionally interconnected metal ions or clusters and polydentate organic linkers that are stabilized by strong metal–ligand interactions [16]. Zeolitic imidazolate frameworks (ZIFs) represent a significant category within metal–organic frameworks (MOFs). These materials, which are formed by linking tetrahedrally coordinated divalent cations (e.g., Zn2+, Fe2+, and Co2+) with imidazolate ligands [17,18,19], exhibit high porosity and exceptional thermal and chemical stability, making them promising for carbon dioxide capture and separation applications [17,19,20]. In membrane technology, ZIFs have been used to make MMMs from polyether block amide for the pervaporation separation of n-butanal/water [21], and phenol/water [22]; from polyvinyl alcohol [23], and polyimide P84 [24] for the pervaporation separation of isopropanol/water; from polybenzimidazole for the pervaporation dehydration of ethanol, isopropanol, butanol [25]; and from polydimethylsiloxane for the pervaporation separation of ethanol/water and 1-butnaol/water [26], among others. Thus, ZIFs have proven themselves as modifiers for creating MMMs.
Carboxymethyl cellulose (CMC) is a highly promising water-soluble cellulose derivative and a naturally abundant polysaccharide valued for its biodegradability, renewability, and biocompatibility [27]. Due to its inherent properties (e.g., mechanical strength, low cost, surface hydrophilicity, etc.), CMC and its hybrid materials find extensive use across diverse sectors, including pharmaceuticals, cosmetics, oil, textiles, food, paper industries, biomedicine, wastewater treatment, and energy production and storage [28]. In membrane technologies, CMC has proven useful as a membrane material for applications such as gas separation [27,29], pervaporation [30,31], and nanofiltration [32].
Pervaporation is a frequently employed technique for the separation of mixtures of low-molecular-weight components and is particularly relevant for separating water–alcohol mixtures. The separation of these mixtures holds significant technological importance, as short-chain alcohols find widespread application in the food, chemical, and pharmaceutical industries. The separation of water/alcohol mixtures through traditional methods such as distillation, esterification, etc., is energy intensive, requires the addition of toxic reagents, and is economically ineffective. The dehydration of alcohols via the pervaporation method uses compact equipment, less energy, and new membrane materials to effectively implement the process. Therefore, despite the diversity of membrane materials, the search for new highly efficient membranes for the pervaporation dehydration of sports fuels is an urgent task. A common model system for studying alcohol dehydration via pervaporation is the isopropanol/water mixture. This particular system presents a separation challenge because isopropanol and water form an azeotrope (12 wt% water, boiling point at 80.3 °C), which limits the effectiveness of conventional distillation [33]. The separation of low-molecular-weight components via a membrane in pervaporation occurs through the “solubility-diffusion” mechanism, which consists of three main steps: (1) sorption of the component, (2) diffusion of the component through the membrane, and (3) desorption of the component from the other membrane side. The introduction of a modifier into a polymer matrix (creation of MMM) allows us to improve, as a rule, two membrane parameters, selectivity and permeation flux, due to the surface modification of the polymer membrane and the change of the free volume. This study presents the first reported development and investigation of CMC-based membranes modified with ZIF-8 particles for the pervaporation dehydration of isopropanol. To the best of our knowledge, no prior work in the literature has explored this specific membrane composition for this application. The effect of introducing ZIF-8 into the CMC matrix on the transport and physicochemical characteristics of membranes was studied. Quantum chemical calculations were used to evaluate the interaction of the polymer, modifier, and components of the feed (water and isopropanol) during pervaporation.
Quantum chemical calculations, especially those based on density functional theory, have become essential in diverse chemical research fields [34]. These calculations allow for the prediction of microscopic properties, including potential sorption sites, and the examination of process mechanisms, as well as the investigation of non-covalent interactions, bond types, and energies. However, applying these computational methods to large-scale systems like peptide chains, nanoparticle clusters, and polymers remains a significant challenge. Conversely, quantum chemical calculations are a well-established and widely used approach for studying MOFs [35,36]. In this study, systems comprising ZIF-8, CMC, and the components of the feed (water and isopropanol) were investigated. Specifically, it investigated the interaction of the carboxymethyl group (CH2-COOH) in the CMC monomer in three different position with the ZIF-8 organic ligand, isopropanol, and water; the interaction of the ZIF-8 organic ligand with isopropanol and water; and the interaction between water and isopropanol. To explain the experimental results, the formation of potential associates, their types, and strengths of non-covalent interactions were assessed using topological analysis of electron density and bond order analysis. This study was carried out to explain the transfer mechanism during pervaporation separation.
Thus, the aim of this study was to develop and study novel dense and supported (prepared with the use of developed different substrates from cellulose acetate and polyacrylonitrile) CMC-based membranes modified with synthesized Zn-based MOF ZIF-8 for enhanced sustainable pervaporation dehydration of isopropanol. The synthesized ZIF-8, developed substrates, and membranes underwent extensive characterization using a variety of techniques, including nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), atomic force microscopy (AFM), surface area analysis, X-ray diffraction analysis (XRD), thermogravimetric analysis (TGA), contact angle measurement, the standard porosimetry method, and swelling experiments. Quantum chemical calculations were used to confirm the interaction between the polymer matrix, modifier, and components of the feed. The transport properties of dense and supported membranes were tested in the pervaporation dehydration of isopropanol. The scheme with the presentation of the study is presented in Figure 1.

2. Materials and Methods

2.1. Materials

Carboxymethyl cellulose (CMC) with Mn = 400 kDa and produced in Bioprod LLC (St. Petersburg, Russia), cellulose acetate (CA) with Mn = 40 kDa and produced in CDA-F Alfa Laval (Copenhagen, Denmark), and polyacrylonitrile (PAN) with Mw = 150 kDa and produced in Ming International Co., (Taiwan, China) were used as membrane materials. Isopropanol (i-PrOH), N,N′-dimethylacetamide (DMA), and dimethyl sulfoxide (DMSO), which were produced in Vekton (St. Petersburg, Russia), and glutaraldehyde (GA, 50 wt% in water, Gala-trade, St. Petersburg, Russia) were applied without further purification. ZIF-8 synthesized at the Saint Petersburg State University (research group “Photoactive nanocomposite materials”) was used as the modifier for the CMC matrix. Materials for ZIF-8 synthesis are described in detail in Supplementary Materials (Sections S1 and S2). The characterization of the phase and chemical composition, as well as the specific surface area value of the synthesized powdered samples, was carried out via XRD, FTIR spectroscopy, and adsorption measurements and presented in detail in Supplementary Materials (Section S3). The obtained characterizations confirmed the formation of the metal–organic framework ZIF-8(Zn) with a specific surface area of 150.968 m2/g. The sample’s morphology was investigated by using the Zeiss Merlin scanning electron microscope. Figure 2 demonstrates the morphology of ZIF-8 samples. The ZIF-8 zeolite–imidazolate framework has flower-like particles with a developed surface area.

2.2. Membrane Preparation

2.2.1. Dense Membranes

A CMC polymer solution was created by stirring CMC in water at 45 °C for 5 h. The solid-phase method was used to prepare CMC+ZIF-8 composites by grinding CMC and ZIF-8 in an agate mortar, with ZIF-8 content up to 15 wt% relative to CMC. The resulting mixture was then dissolved in distilled water at 45 °C for 5 h with stirring. The CMC and CMC+ZIF-8 dispersions were then sonicated at room temperature. Finally, the dispersions were poured into Petri dishes to form dense membranes, which were dried in an oven at 40 °C for 24 h. The thickness of the resulting dense membranes was 40 ± 5 μm, measured with a micrometer.

2.2.2. Porous Membranes (Substrates)

Porous substrates were fabricated using non-solvent-induced phase separation (NIPS). A 15 wt% solution of CA in DMA was prepared via stirring at room temperature for 8 h using an overhead stirrer. For PAN-based substrates, a 15 wt% PAN solution was created by dissolving the polymer in either DMA or DMSO at 120 °C for 5 h with continuous overhead stirring. The CA or PAN solution was then cast onto a glass plate using a casting knife with a 200 µm gap and subsequently immersed in a distilled water coagulation bath at room temperature. The resulting porous substrates were allowed to solidify for 24 h before being used as a foundation for the CMC-based selective layer in the preparation of supported membranes.

2.2.3. Supported Membranes

Supported CMC and CMC+ZIF-8 membranes were prepared by applying the corresponding 1 wt% dispersions onto a porous membrane (substrate), followed by air drying for 24 h. Chemical cross-linking was employed to improve the stability of the supported CMC-based membranes in diluted solutions [37]. The cross-linking procedure consisted of immersing the membranes in a 1 wt% glutaraldehyde (GA) solution containing 0.5 wt% H2SO4 for 1 min, followed by air drying for 30 min and oven-drying at 60 °C for 10 min.
Table 1 shows the designations of the dense and supported membranes developed in this study.

2.3. Characterization Techniques

2.3.1. Study of Structure

Fourier transform infrared (FTIR) spectroscopy was performed to study the structural characteristics of the CMC and CMC+ZIF-8 membranes. A BRUKER-TENSOR 27 spectrometer (Bruker, Billerica, MA, USA) equipped with an attenuated total reflectance (ATR) accessory was used. Spectra were recorded at a controlled temperature of 25 °C over a wave number range of 600 to 4000 cm−1.
The molecular structure of the membranes was studied using nuclear magnetic resonance (NMR) spectroscopy. A Bruker Avance III 400 WB NMR spectrometer (Bruker, Ettlingen, Germany) with a 3.2 mm CP/MAS probe was used. The spectrometer operated with a magnetic field of 9.4 T and a corresponding Larmor frequency of 100.64 MHz. Samples were packed into 3.2 mm zirconia rotors and spun at 12.5 kHz during the experiments. Tetramethylsilane (TMS) in liquid form was used as an external standard to calibrate the 13C nuclei. {1H}13C CP/MAS NMR data were obtained from 8192 accumulated scans using a contact time of 2 ms and a relaxation delay of 5 s.

2.3.2. Study of Morphology

Scanning electron microscopy (SEM) with a Zeiss AURIGA Laser (Carl Zeiss SMT, Oberhochen, Germany) operating at 1 kV was used to analyze the internal morphology and surface features of the dense and supported CMC and CMC+ZIF-8 membranes and porous substrates. For cross-sectional imaging, samples were fractured in liquid nitrogen.
Atomic force microscopy (AFM), performed with an NT-MDT NTegra Maximus microscope (NT-MDT Spectrum Instruments, Moscow, Russia) in tapping mode and using standard silicon cantilevers (15 N·m−1), was employed to characterize the surface topology of the CMC and CMC+ZIF-8 membranes.

2.3.3. Study of Transport Properties

To assess the transport properties of the developed membranes, pervaporation experiments were conducted at 22 °C with constant agitation [33]. The experimental setup is illustrated in Figure 3. The composition of both the feed and permeate streams was analyzed using a Chromatec Crystal 5000.2 gas chromatograph (Chromatec, Yoshkar-Ola, Russia) equipped with a “Hayesep R” column and a thermal conductivity detector.
The permeation flux J (kg/(m2h)) was calculated using Equation (1) [38]:
J = W A · t ,
where W (kg) is the weight of permeate, A (m2) is the effective membrane area, and t (h) is the measurement time.
The separation factor (β) was calculated using Equation (2) [39]:
β = y i y j x i x j
where yi and xi are the weights of the water in the permeate and the feed, respectively, and yj and xj are the weights of isopropanol in the permeate and the feed, respectively.

2.4. Theoretical Consideration

Quantum chemical calculations were performed using Gaussian 16 W, Revision A.03 [40]. The calculations employed the B3LYP function [41,42,43] along with the 6-311++G(d, p) basis set. The systems were evaluated in a singlet state. The optimized structures did not exhibit any negative eigenvalues in the Hessian matrix, and thermodynamic characteristics were obtained at 298.15 K and 101.3 kPa. The wavefunctions were analyzed using the multifunctional wavefunction analyzer (Multiwfn 3.8, release date: 17 April 2024) [44]. The VMD software (Version 1.9.4a53 (29 June 2021)) was utilized for the 3D visualization of non-covalent interaction plots (NCIplots) [45].

3. Results and Discussion

This study introduces novel CMC-based pervaporation membranes incorporating a Zn-based MOF (ZIF-8) to promote a sustainable pervaporation process. This section isdivided into three subsections:
  • Section 3.1 describes the development of dense CMC and CMC+ZIF-8 membranes, examining their transport properties in pervaporation (Section 3.1.1) and their structural and physicochemical characteristics (Section 3.1.2).
  • Section 3.2 details the computational investigation, focusing on the creation and analysis of hypothetical associates (Section 3.2.1) and the study of non-covalent interactions (Section 3.2.2).
  • Section 3.3 presents the development and investigation of supported CMC and CMC+ZIF-8 membranes. This includes the development and characterization of porous substrates (Section 3.3.1), followed by the analysis of untreated supported membranes (Section 3.3.2) and cross-linked supported membranes (Section 3.3.3).

3.1. The Development and Investigation of Dense CMC and CMC+ZIF-8 Membranes

3.1.1. Pervaporation Performance of Dense Membranes

To determine the optimal MOF content, ZIF-8 was incorporated into the CMC matrix at concentrations ranging from 5 to 15 wt%. Figure 4 shows the permeation flux of dense membranes based on the CMC and CMC+ZIF-8 (5–15 wt%) composites in the pervaporation separation of water/isopropanol (12 and 20 wt% water) mixtures.
All dense membranes based on CMC and composites of CMC+ZIF-8 with different amounts of the modifier showed high water content in the permeate (99.99 wt%). It was found that the introduction of ZIF-8 up to 10% led to an increase in the permeation fluxes up to 0.124 and 0.195 kg/(m2h). The incorporation of plate-like ZIF-8, characterized by its highly porous framework, into the CMC matrix induces structural and morphological changes within the membrane during modification [46,47]. These changes, including the generation of “plastic deformations” within the internal structure and an increase in surface roughness (confirmed by SEM and AFM data below), can result in an expanded effective contact area and a greater density of sorption sites. Consequently, this promotes increased swelling of the membrane in the feed (confirmed by swelling degree data below), ultimately leading to increased permeability [33,48]. A more energetically favorable interaction of the feed components with ZIF-8 compared to CMC was also observed through theoretical considerations (Section 3.2), resulting in an increase in permeation flux of modified membranes. A further increase of the ZIF-8 content to 15 wt% in the CMC matrix leads to a slight decrease in the permeation fluxes up to 0.096 and 0.176 kg/(m2h) during the pervaporation separation of water/isopropanol mixtures with 12 and 20 wt% water, respectively. The observed reduction in permeation flux for the membrane containing 15 wt% ZIF-8 can be attributed to significant ZIF-8 agglomeration within the CMC matrix and on the membrane surface. This agglomeration, as confirmed by SEM and AFM data, hinders the efficient transport of feed components across the membrane [49]. Therefore, the optimal concentration of ZIF-8 in the CMC matrix was chosen to be 10 wt%.

3.1.2. Structure and Physicochemical Properties of Dense CMC and CMC+ZIF-8 Membranes

The structural characteristics of the CMC and CMC+ZIF-8(10%) (CMC-0 and CMC-10) membranes were studied using FTIR spectroscopy (Figure 5).
The FTIR spectrum acquired for the unmodified CMC membrane demonstrates a number of characteristic spectral features, including prominent peaks located at 3373 cm−1, 1587 cm−1, and 1413 cm−1. These particular absorption bands are attributable to the vibrational modes associated with the presence of hydroxyl (–OH) functional groups [37], carboxyl (COO–) functional groups, as well as the carboxylate moiety when present in its salt form [50]. Additionally, a strong absorption is observable within the spectral region spanning from 900 cm−1 to 1250 cm−1, serving as an indicator for the presence of ether linkages and bonding motifs intrinsic to the CMC polymeric structure [50]. The introduction of 10 wt% ZIF-8 leads to the appearance of a new peak with an absorption maximum at 1366 cm−1, which may correspond to the peak of ZIF-8 with maximum intensity, and corresponds to the extension of the entire ring stretching of ZIF-8 (Figure S2). The presence of ZIF-8 in the polymer matrix was also confirmed via NMR spectroscopy. The remaining characteristic peaks of the modifier coincide with the peaks of the polymer matrix.
The structural characteristics of the CMC-0 and CMC-10 membranes were also studied through NMR spectroscopy (Figure 6). The schemes of the CMC polymer block and the organic component ZIF-8 with the numbering of the carbon atom positions are presented in Figure 6. The position of the components, which corresponds to the numbered carbon atom positions in the structural schemes, is shown under the corresponding spectra (Figure 6).
The 13C NMR spectra of pure CMC-0 and ZIF-8 correspond to those reported in the literature [51,52]. Visually, the spectrum of the modified CMC-10 membrane is a sum of the two previously described spectra (pure CMC and ZIF-8). However, by normalizing the spectra of the pure materials with the corresponding peaks of the modified CMC-10 membrane (the line from the methyl group for ZIF-8 (about 15 ppm) and from the carboxyl group for CMC (about 180 ppm)) and subtracting them from this NMR spectrum, the lower spectrum (grey) was obtained. A line at about 75 ppm is clearly visible in the spectrum obtained. This component is close to the lines from the CMC carbon atoms in positions 2 and 3. This behavior may be attributed to the involvement of the terminal functional groups attached to these atoms in structural interactions with the modifier, as evidenced by the results of the computational investigation, including changes in Gibbs free energies and values of bond orders (confirmed through computational investigation, as shown in Section 3.2).
The morphology of the dense CMC-based membranes with different concentrations of ZIF-8 was studied using SEM (Figure 7).
The SEM micrographs presented for the pristine CMC-0 membrane show a uniform and consistent structure, characterized by a ribbed morphology in the cross-sectional view, with no discernible defects or irregularities (Figure 7). However, the introduction of ZIF-8 into the polymer matrix induces a marked change in the internal morphological characteristics of the membranes, specifically leading to the development of “plastic deformations” within the cross-sectional structure. This particular effect may be attributed to the crystalline properties of the modifier material. Upon the introduction of ZIF-8, “flower-like” particles (Figure 2) appear on the surface of the membranes, the number of which increases with increasing concentrations of modifiers.
Since pervaporation, as suggested by the “solubility-diffusion” mechanism, begins with the sorption of components onto the membrane surface, changes to this surface resulting from modification are likely to have a noticeable impact on the separation properties. AFM was employed to characterize the surface topology of CMC and CMC+ZIF-8 membranes with differing ZIF-8 contents. AFM images with a 30 × 30 μm scan size are provided in Figure 8, along with a presentation of the average surface roughness (Ra) calculated from these images.
Figure 8 shows that the average surface roughness of the CMC membranes increases with increasing ZIF-8 loading. The CMC-15 membrane, in particular, exhibits the highest average roughness (Ra = 40.5 nm), a finding corroborated by SEM data (Figure 7). This suggests that ZIF-8 particles migrate significantly to the membrane surface. The resulting increase in surface roughness enhances the effective surface area available for interaction with feed components, leading to improved sorption and faster permeation through the modified membranes. This, in turn, explains the observed increase in permeation flux, as confirmed by the pervaporation data presented in Figure 4.
To evaluate the thermal stability of the dense CMC-0, CMC-10, and CMC-15 membranes, along with ZIF-8, the membranes were subjected to TGA. The corresponding thermograms are shown in Figure 9.
The TG curves for the dense membranes show three distinct weight loss stages. The first stage (30–200 °C), corresponding to water evaporation and a loss of low-molecular-weight compounds, accounts for 9.5% (CMC-0), 8.7% (CMC-10), and 7.3% (CMC-15) weight losses at 200 °C. The second stage (200–320 °C) is attributed to the thermal decomposition of the carboxyl and hydroxyl groups. The final weight loss stage above 320 °C corresponds to the decomposition of the polymer backbones [53]. The modified membranes exhibit enhanced thermal stability (less weight loss compared to the pristine CMC-0 membrane), attributed to the high thermal stability of ZIF-8, which only begins to decompose above 500 °C (Figure 9). This level of thermal stability suggests that the CMC-based membranes are likely to be stable under high-temperature industrial applications.
The swelling degree of the dense membranes based on CMC and its composites with different concentrations of ZIF-8 is studied and presented in Table 2.
The swelling degree in the water/isopropanol mixture (12/88 wt%) slightly increased with increasing ZIF-8 in the CMC matrix, which was due to the increase of sorption sites on the membrane surface (confirmed by AFM data (Figure 8)) and a more energetically favorable interaction of the water/isopropanol mixture with the MOF compared to CMC (confirmed by theoretical considerations (Section 3.2)). The increase in swelling leads to an increase in permeation flux for the modified membranes (Figure 4).
The changes in the hydrophilic–hydrophobic balance of the surface of the dense membranes based on CMC and its composites with different concentrations of ZIF-8 membranes were studied through the contact angle of the water measurement, as shown in Figure 10.
An increase in the water contact angle was observed; i.e., upon the introduction of the modifier, a hydrophobization of the surface was observed, which was associated with the introduction of the hydrophobic ZIF-8 [54]. The increase in the contact angle can also be associated with a decrease in the oxygen-containing functional groups of the CMC on the surface during the interaction with the organic ligand (MIM) of ZIF-8 (confirmed by NMR data (Figure 6) and computational investigation (Section 3.2)).

3.2. Computational Investigation

The investigation of polymer–modifier interactions is essential for predicting material properties and explaining existing correlations. Weak adhesion between the polymer and MOF can lead to interfacial defects and undesirable voids, reducing separation selectivity and deteriorating the mechanical properties of the membranes. Conversely, strong interactions between the polymer matrix and the filler may restrict the mobility of the polymer chains, thereby diminishing the diffusion of penetrating molecules and reducing flux [55]. The significant impact of these effects has led to the establishment of strategies aimed at improving compatibility between fillers and polymers, which include modifications and alterations to the size and morphology of fillers, polymer functionalization, the addition of a third component, as well as in situ growth and annealing processes [5]. Consequently, the study of interfacial interactions remains a vital and necessary focus for achieving membranes with optimized properties and for elucidating the observed relationships.
In this study, the molecular geometries of several substances, including water, i-PrOH, the 2-methylimidazolate anion (MIM, a ZIF-8 ligand), and model units of mono-substituted CMC at various positions (6th—1-CMC, 2nd—2-CMC, and 3rd—3-CMC (Figure 6)), were optimized. Different substitution positions of the polymer were examined to evaluate their influence on the potential for forming non-covalent interactions. Several hypothetical associative complexes were subsequently created and optimized to investigate the potential non-covalent interactions among these compounds. No further processing was conducted for complexes that demonstrated the least favorable interactions. Detailed structural information, including Cartesian coordinates for all structures, is provided in Table S1 (in Supplementary Materials).

3.2.1. The Creation and Investigation of Hypothetical Associates

Computational modeling was used to determine and optimize the geometries of theoretical complexes formed between membrane components (CMC and the ZIF-8 ligand) and feed mixture (water and isopropanol) constituents. Table S2 (in Supplementary Materials) displays the changes in thermodynamic potentials during the formation of the associates. Meanwhile, Table 3 presents the standard Gibbs free energy changes (ΔG0) for the most energetically favorable complexes.
Based on the changes in Gibbs energy presented in Table 3, a significant affinity of the CMC for the introduced modifier was demonstrated. This finding aligns with the uniform distribution of ZIF-8 within the polymer matrix, as evidenced by cross-sectional SEM images (Figure 7). The investigation of non-covalent interactions, as detailed in Section 3.2.2, indicated that the substantial energy gain observed during the interaction between the MIM anion and CMC was attributed to the protonation of MIM by the hydrogen from the carboxyl group (Figure 11).
A similar effect with the benzimidazolate anion was previously reported in the work by [56], linking this phenomenon to the effectiveness of imidazole anions as nitrogen-donor ligands. When considering the interactions of CMC isomers with MIM, it was found that 2-CMC and 3-CMC were energetically more favorable, as confirmed through NMR spectroscopy (Figure 6). This observation is likely related to the inductive effects of the hydroxyl and ether groups within the cellulose ring, leading to a more efficient redistribution of electronic density and the activation of the carboxyl substituent. Furthermore, it was shown that the interaction of MIM with the components of the feed was energetically more favorable than its interaction with the CMC. This result is in accordance with previously observed increases in permeation fluxes (Figure 4) and swelling degrees (Table 2) of modified membranes.

3.2.2. Investigation of Non-Covalent Interactions

Bond lengths and orders were measured to evaluate the strength of non-covalent interactions among CMC, the MIM ligand, and the feed components. This investigation involved topological and bond order analyses conducted using Multiwfn 3.8. The results revealed the presence of bond critical points (BCPs) and bond paths, confirming the existence of these interactions (Figure 11 and Figure 12). Based on the presented images (blue NCIplots index isosurfaces), the formed non-covalent interactions can be classified as hydrogen bonds of varying strength [57]. A detailed summary of the QTAIM parameters at the BCPs is provided in Table S3 in Supplementary Materials.
To evaluate the strength of the bonds, the Wiberg bond index (WBI) [58,59] and the Fuzzy bond order (FBO) [60] were employed. These indices were selected for their robustness against variations in the basis set and their capability to effectively quantify the strength of bonding interactions. The outcomes of the wave function post-processing, along with the interaction lengths and the ratio of these lengths to the sum of van der Waals radii (R), are summarized in Table 4.
In the case of the CMC⋯MIM associates, the interaction lengths, which are less than the sum of the van der Waals radii and comparable to the sum of covalent radii, along with the WBI values of 0.691, 0.670, and 0.670 for 1-CMC, 2-CMC, and 3-CMC, respectively, may indicate the presence of covalent bonds resulting from the observed deprotonation of the carboxyl substituent (Figure 11). Conversely, higher WBI values for the interaction O(COO*H)///H(COOH) indicate a preferential interaction of MIM with the carboxyl group at the second and third positions, as evidenced by the NMR investigation (Figure 6). WBI values for the remaining associative interactions [61], which are below 0.3, confirm their non-covalent nature. When examining the individual hydrogen bonds of MIM with the components of the feed, the binding strength decreases in the order of i-PrOH > H2O (0.214 > 0.184 WBI, respectively). Thus, despite the similar changes in Gibbs free energy (Table 3), the interaction of MIM with i-PrOH results in the formation of stronger hydrogen bonds compared to those with water. This finding aligns with the observed decrease in selectivity when creating supported composite membranes as opposed to the supported CMC membrane, where a reduction in the thickness of the selective layer leads to a greater contribution from sorption compared to the diffusion of the feed components (Section 3.3). The conclusions drawn are consistent with the computed hydrogen bonding energies presented in Table S3 in Supplementary Materials. It is noteworthy that despite the stronger hydrogen interactions between water and i-PrOH with MIM compared to CMC, the introduction of the modifier results in surface hydrophobization (Table 2). This may be due to the fact that CMC possesses a greater number of functional oxygen-containing groups compared to MIM, which has only one active site (as the second site participates in an interaction with Zn), and the strong interaction between MIM and CMC may reduce the number of available polymer functional groups. Additionally, the methyl fragment of MIM appears to contribute significantly to hydrophobization, as the previous work by Dmitrenko et al. [56] has demonstrated the hydrophilizing ability of the benzimidazolate anion.

3.3. The Development and Investigation of Supported CMC and CMC+ZIF-8 Membranes

3.3.1. The Development and Investigation of Porous Substrates

Contrary to the common assumption that the substrate of a supported (composite) membrane has a negligible effect on the penetration of low-molecular-weight compounds in pervaporation, research suggests that the polymer type and substrate porosity can have a significant influence on the transport behavior of the membrane [62,63,64]. Therefore, in this work, the mass transfer mechanism of pervaporation was clarified by characterizing the porous substrates prepared from CA and PAN in different solvents (in DMA and DMSO). This characterization was achieved through a combination of methods, including SEM, AFM, and standard porosimetry.
The inner structure of porous substrates was studied using SEM. The SEM cross-sectional micrographs of porous CA, PAN(DMA), and PAN(DMSO) substrates are presented in Figure 13.
It was found that despite the same method of preparation of porous substrates (phase inversion method via NIPS), the porous structure of the obtained membranes also depended on the polymer and solvent. Thus, the CA membrane has a finer porous structure throughout its thickness with a large “vacuole-shaped” structure. PAN porous membranes have a “finger-shaped” structure, and their porous systems differ depending on the solvents used—DMA or DMSO. For PAN(DMA), shorter “finger-shaped” pores were observed, which then changed to “vacuole-shaped” pores, while for the PAN(DMSO) porous substrate, the finger-like pores were longer and predominant throughout the entire thickness of the membrane.
AFM was used to evaluate the deference in the surface morphology of porous CA, PAN(DMA), and PAN(DMSO) substrates. AFM images with a 30 × 30 μm scan size are provided in Figure 14, along with a presentation of the average surface roughness (Ra) calculated from these images.
It was found that the CA substrate had the lowest roughness (6.4 nm), which could lead to the formation of the thinnest selective layer of CMC. The lowest surface roughness may be associated with the dense porous structure of the CA substrate, which was confirmed through SEM (Figure 13). The substrates based on PAN have the same roughness (~15 nm), which is associated with the similar structure of the upper selective layer (Figure 13).
To study the porosity of porous CA, PAN(DMA), and PAN(DMSO) substrates, the standard porosimetry method was applied. The obtained data are presented in Table 5.
The porosity parameters for the substrates based on PAN are higher than those for the CA substrate, which is consistent with the data obtained using SEM (Figure 13).

3.3.2. The Development and Investigation of Untreated Supported CMC and CMC+ZIF-8 Membranes

To increase the permeation flux of the dense CMC-0 and CMC-10 membranes, supported membranes were developed. Porous CA, PAN(DMA), and PAN(DMSO) membranes were used as substrates, on which thin selective layers based on CMC and the composite with 10 wt% ZIF-8 were deposited. The pervaporation performance of the developed membranes was assessed in pervaporation with water/isopropanol mixtures with water contents of 12 and 20 wt% (Figure 15).
It was found that applying a thin layer of CMC-0 onto all porous substrates (CA, PAN(DMA), and PAN(DMSO)) resulted in an increase in permeation flux compared to the dense CMC-0 membrane while maintaining the maximum water content in the permeate (99.99 wt%). The highest permeation flux is demonstrated by the supported CMC-0/CA membrane. The maximum permeation flux among the supported membranes from pristine CMC is associated with the lowest thickness of the upper selective layer of the CA substrate (confirmed by SEM below (Figure 16)). Thus, the porous CA membrane was chosen as the optimal substrate for the development of supported membranes with a thin selective layer from CMC.
The introduction of 10 wt% ZIF-8 into the CMC matrix and the creation of a supported membrane using a porous CA substrate lead to a greater increase in permeation flux: ~6.1 times compared to the dense CMC-0 membrane and ~1.3 times compared to the supported CMC-0/CA membrane in the pervaporation of a water/isopropanol mixture (12 wt% of water). The increase in permeation flux is associated with the introduction of ZIF-8 and an increase in surface roughness, which leads to an increase in sorption centers on the membrane surface (confirmed by AFM below (Figure 17)). For the modified CMC-10/CA membrane, a slight decrease in water content in the permeate to 98 wt% was noted when separating a water/isopropanol mixture (20 wt% water). This decrease may be due to surface hydrophobization during the introduction of ZIF-8 into the CMC matrix (confirmed by contact angle measurements (Figure 8)) and the favorable interaction of the MIM ligand with i-PrOH (confirmed in Section 3.2.2), which leads to an increase in the sorption of isopropanol and an increase in its diffusion through a thin selective layer.
SEM and AFM were used to characterize the internal structure and surface morphology of the developed supported CMC and CMC-10/CA membranes. Cross-sectional and surface SEM micrographs are shown in Figure 16.
It was found that the use of various porous membranes as substrates for creating supported membranes led to the formation of a selective CMC-based layer with different thicknesses. Thus, when using the developed porous CA membrane, a selective layer based on pure CMC with a thickness of ~1 µm is formed on the surface of the porous substrate. The smallest thickness of the selective layer can be associated with the smallest value of surface roughness of the porous CA membrane. The use of porous PAN-based membranes obtained with various solvent leads to the formation of selective CMC layers of similar thicknesses for supported membranes: ~3.2 µm for the CMC-0/PAN(DMA) membrane and ~3.3 µm for the CMC-0/PAN(DMSO) membrane. Consequently, the supported membranes prepared using PAN substrates, which resulted in thicker selective layers, exhibited the lowest permeation flux values (Figure 15). SEM micrographs reveal that the unmodified, CMC-based supported membranes possess a similar surface structure (Figure 16). The incorporation of 10 wt% ZIF-8, however, caused an increase in the selective layer thickness to approximately 2 µm. This thickening is likely due to a slight increase in the viscosity of the modified polymer solution.
AFM images with a 30 × 30 μm scan size for supported membranes are provided in Figure 17, along with a presentation of the average surface roughness (Ra) calculated from these images.
It was found that for unmodified supported CMC-based membranes, close surface average roughness values were obtained, which was consistent with the SEM surface micrographs (Figure 16). The introduction of 10 wt% ZIF-8 leads to an increase in roughness by ~5 times, which results in an increase in sorption centers on the membrane surface and the maximum permeation flux among composite membranes (Figure 15).

3.3.3. The Development and Investigation of Cross-Linked Supported CMC and CMC+ZIF-8 Membranes

To use membranes with optimal transport characteristics over the entire concentration range, supported CMC-0/CA and CMC-10/CA membranes were cross-linked using GA, and their transport properties were studied through the pervaporation of a water/isopropanol mixture over the entire concentration range (Figure 18).
It was found that the cross-linking of supported membranes led to the stability (invariability) of the membrane selective layer when separating a water/isopropanol mixture with high water content. In this case, a high water content in the permeate (more than 92 wt%) was observed for supported cross-linked membranes. For the modified CMC-10/CACL membrane, the water content in the permeate was slightly lower than that for the unmodified CMC-0/CACL membrane, which, as in the case of untreated supported membranes, was associated with surface hydrophobization and isopropyl alcohol sorption on the membrane surface. The permeation flux of cross-linked membranes was slightly lower than that of untreated supported membranes, which was due to the cross-linking of polymer chains and a decrease in free volume. The cross-linked supported CMC-10/CACL membrane has higher permeation flux (0.136–1.968 kg/(m2h)) compared to the cross-linked unmodified supported CMC-0/CACL membrane. Thus, the CMC-10/CACL membrane has optimal transport properties: high permeation flux with high water content in the permeate (˃92 wt% water) over the entire concentration range of pervaporation of the water/isopropanol mixture.

4. Conclusions

In the present study, novel dense and supported mixed matrix membranes based on water-soluble cellulose derivative CMC modified with the ZIF-8 for enhanced sustainable pervaporation dehydration of isopropanol were developed.
The influence of the ZIF-8 modifier on the transport and physicochemical properties of the CMC membranes was studied. Increasing the ZIF-8 content (5–15 wt%) in the CMC matrix improved permeation flux and maintained high water content in the permeate (99.99%) for isopropanol dehydration. This was attributed to structural changes, increased roughness and swelling degree, and favorable ZIF-8 and feed component interaction.
Supported membranes were fabricated using porous CA and PAN substrates to enhance permeation flux. The CMC that formed the thinnest selective layer on a CA substrate achieved the optimal membrane performance. The cross-linked CMC-10/CACL membrane with 10 wt% ZIF-8 exhibited high permeation flux (0.136–1.968 kg/(m2·h)) and >92 wt% water content in the permeate, demonstrating suitability for industrial dehydration, even at elevated temperatures.

Supplementary Materials

The following supporting information can be downloaded at https://www.mdpi.com/article/10.3390/su17093801/s1, Figure S1. XRD patterns of synthesized ZIF-8 sample. The positions of the main reflexes of structure ZIF-8 are marked with black vertical lines; Figure S2. IR spectra of ZIF-8 sample; Figure S3. Nitrogen adsorption isotherms for the ZIF-8 sample; Table S1. Cartesian atomic coordinates (in Angstroms) for all optimized equilibrium model structures; Table S2. The changes of thermodynamic potential values during the association of components; Table S3. Electron density ρ(r) (e/bohr3), Laplacian ∇2ρ(r) (e/bohr5), potential energy density V(r) (Hartree), and Lagrangian kinetic energy G(r) (Hartree) at the bond CP (3, −1), corresponding to different noncovalent interactions. aE, bE, cE, and dE (kJ/mol) are values of interaction energy. References [65,66,67,68,69,70,71] are presented in Supplementary Materials.

Author Contributions

Conceptualization, A.K. and A.P.; methodology, A.P., A.R., A.E., A.M. (Anton Mazur) and R.S.; formal analysis, A.K.; investigation, A.M. (Anna Mikulan), A.S. (Anastasia Stepanova), M.P., N.R., A.M. (Anton Mazur) and A.S. (Anna Shurukhina); resources, A.P.; data curation, A.K.; writing—original draft preparation, A.K., R.D., A.R. and M.D.; writing—review and editing, A.K., R.D., M.D. and A.P.; visualization, A.K. and R.D.; supervision, A.P.; project administration, A.P.; funding acquisition, A.P. All authors have read and agreed to the published version of the manuscript.

Funding

This study was supported by the Russian Science Foundation, grant number 20-79-10064, https://rscf.ru/en/project/20-79-10064/ (accessed on 18 April 2025).

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

Data will be made available upon request.

Acknowledgments

The experimental work of this study was facilitated by the equipment from the Chemical Analysis and Materials Research Centre, Centre for X-ray Diffraction Methods, Magnetic Resonance Research Centre, Centre for Innovative Technologies of Composite Nanomaterials, Nanophotonics Centre, Cryogenic department, Computing Centre, Geomodel, Centre for Diagnostics of Functional Materials for Medicine, Pharmacology and Nanoelectronics, Thermogravimetric and Calorimetric Research Centre, and the Interdisciplinary Resource Centre for Nanotechnology at the St. Petersburg State University.

Conflicts of Interest

The authors declare no conflicts of interest.

References

  1. Atlaskin, A.A.; Trubyanov, M.M.; Yanbikov, N.R.; Bukovsky, M.V.; Drozdov, P.N.; Vorotyntsev, V.M.; Vorotyntsev, I.V. Total Reflux Operating Mode of Apparatuses of a Membrane Column Type during High Purification of Gases to Remove a Highly Permeable Impurity. Pet. Chem. 2018, 58, 508–517. [Google Scholar] [CrossRef]
  2. Davletbaeva, I.; Zaripov, I.; Mazilnikov, A.; Davletbaev, R.; Sharifullin, R.; Atlaskin, A.; Sazanova, T.; Vorotyntsev, I. Synthesis and Study of Gas Transport Properties of Polymers Based on Macroinitiators and 2,4-Toluene Diisocyanate. Membranes 2019, 9, 42. [Google Scholar] [CrossRef] [PubMed]
  3. Besha, A.T.; Tsehaye, M.T.; Tiruye, G.A.; Gebreyohannes, A.Y.; Awoke, A.; Tufa, R.A. Deployable Membrane-Based Energy Technologies: The Ethiopian Prospect. Sustainability 2020, 12, 8792. [Google Scholar] [CrossRef]
  4. Gui, S.; Mai, Z.; Fu, J.; Wei, Y.; Wan, J. Transport Models of Ammonium Nitrogen in Wastewater from Rare Earth Smelteries by Reverse Osmosis Membranes. Sustainability 2020, 12, 6230. [Google Scholar] [CrossRef]
  5. Yin, J.; Zhang, C.; Ding, S.; Du, H.; Tan, Z.; Li, M.; Wang, B.; Wang, T. The strategies to improve the interfacial compatibility in mixed-matrix membranes: A review. Mater. Today Energy 2025, 49, 101811. [Google Scholar] [CrossRef]
  6. Jia, Z.; Wu, G. Metal-organic frameworks based mixed matrix membranes for pervaporation. Microporous Mesoporous Mater. 2016, 235, 151–159. [Google Scholar] [CrossRef]
  7. Penkova, A.V.; Kuzminova, A.I.; Dmitrenko, M.E.; Surkova, V.A.; Liamin, V.P.; Markelov, D.A.; Komolkin, A.V.; Poloneeva, D.Y.; Laptenkova, A.V.; Selyutin, A.A.; et al. Novel pervaporation mixed matrix membranes based on polyphenylene isophtalamide modified by metal–organic framework UiO-66(NH2)-EDTA for highly efficient methanol isolation. Sep. Purif. Technol. 2021, 263, 118370. [Google Scholar] [CrossRef]
  8. Zhang, H.; Xiao, F.; Wu, Y. Fluorinated Metal–Organic Framework–Polymer Mixed Matrix Membrane with Tunable Hydrophobic Channel for Efficient Pervaporation of Butanol/Water. Small Struct. 2024, 5, 2300333. [Google Scholar] [CrossRef]
  9. Liu, R.; Sui, Y.; Wang, X. Metal–organic framework-based ultrafiltration membrane separation with capacitive-type for enhanced phosphate removal. Chem. Eng. J. 2019, 371, 903–913. [Google Scholar] [CrossRef]
  10. Al-Shaeli, M.; Smith, S.J.D.; Jiang, S.; Wang, H.; Zhang, K.; Ladewig, B.P. Long-term stable metal organic framework (MOF) based mixed matrix membranes for ultrafiltration. J. Membr. Sci. 2021, 635, 119339. [Google Scholar] [CrossRef]
  11. Li, S.; Liu, Y.; Wong, D.A.; Yang, J. Recent Advances in Polymer-Inorganic Mixed Matrix Membranes for CO2 Separation. Polymers 2021, 13, 2539. [Google Scholar] [CrossRef] [PubMed]
  12. Jeazet, H.B.T.; Staudt, C.; Janiak, C. Metal-organic frameworks in mixed-matrix membranes for gas separation. Dalton. Trans. 2012, 41, 14003–14027. [Google Scholar] [CrossRef] [PubMed]
  13. Daglar, H.; Aydin, S.; Keskin, S. MOF-based MMMs breaking the upper bounds of polymers for a large variety of gas separations. Sep. Purif. Technol. 2022, 281, 119811. [Google Scholar] [CrossRef]
  14. Yao, A.; Hua, D.; Zhao, F.; Zheng, D.; Pan, J.; Hong, Y.; Liu, Y.; Rao, X.; Zhou, S.; Zhan, G. Integration of P84 and porphyrin–based 2D MOFs (M−TCPP, M = Zn, Cu, Co, Ni) for mixed matrix membranes towards enhanced performance in organic solvent nanofiltration. Sep. Purif. Technol. 2022, 282, 120022. [Google Scholar] [CrossRef]
  15. Kuzminova, A.; Dmitrenko, M.; Zolotarev, A.; Korniak, A.; Poloneeva, D.; Selyutin, A.; Emeline, A.; Yushkin, A.; Foster, A.; Budd, P.; et al. Novel Mixed Matrix Membranes Based on Polymer of Intrinsic Microporosity PIM-1 Modified with Metal-Organic Frameworks for Removal of Heavy Metal Ions and Food Dyes by Nanofiltration. Membranes 2021, 12, 14. [Google Scholar] [CrossRef]
  16. Lalawmpuia, R.; Lalhruaitluangi, M.; Lalhmunsiama; Tiwari, D. Metal organic framework (MOF): Synthesis and fabrication for the application of electrochemical sensing. Environ. Eng. Res. 2024, 29, 230636. [Google Scholar] [CrossRef]
  17. Phan, A.; Doonan, C.J.; Uribe-Romo, F.J.; Knobler, C.B.; O’Keeffe, M.; Yaghi, O.M. Synthesis, Structure, and Carbon Dioxide Capture Properties of Zeolitic Imidazolate Frameworks. Acc. Chem. Res. 2010, 43, 58–67. [Google Scholar] [CrossRef]
  18. Li, M.-Y.; Liu, J.; Gao, R.; Lin, D.-Y.; Wang, F.; Zhang, J. Design and synthesis of zeolitic tetrazolate-imidazolate frameworks. Mater. Today Adv. 2021, 10, 100145. [Google Scholar] [CrossRef]
  19. Nazir, M.A.; Ullah, S.; Shahid, M.U.; Hossain, I.; Najam, T.; Ismail, M.A.; Rehman, A.U.; Karim, M.R.; Shah, S.S.A. Zeolitic imidazolate frameworks (ZIF-8 & ZIF-67): Synthesis and application for wastewater treatment. Sep. Purif. Technol. 2025, 356, 129828. [Google Scholar] [CrossRef]
  20. Chen, B.; Yang, Z.; Zhu, Y.; Xia, Y. Zeolitic imidazolate framework materials: Recent progress in synthesis and applications. J. Mater. Chem. A 2014, 2, 16811–16831. [Google Scholar] [CrossRef]
  21. Cai, P.; Li, J.; Song, D.; Zhang, N.; Wang, N.; An, Q.-F. Enhancing permeability and stability of ZIF-8/PEBA pervaporation membrane through interface-induced directional nanoparticle distribution. J. Membr. Sci. 2024, 695, 122489. [Google Scholar] [CrossRef]
  22. Fang, L.J.; Chen, J.H.; Yang, Q.; Lin, W.W.; Lin, Q.J.; He, Y.S.; Zhuo, Y.Z. S-ZIF-8/PEBA/ZIF-8 pervaporation membrane with in situ growing of ZIF-8 active layer on the surface owing outstanding phenol enrichment performance. J. Taiwan Inst. Chem. Eng. 2022, 134, 104356. [Google Scholar] [CrossRef]
  23. Benzaqui, M.; Semino, R.; Carn, F.; Tavares, S.R.; Menguy, N.; Giménez-Marqués, M.; Bellido, E.; Horcajada, P.; Berthelot, T.; Kuzminova, A.I.; et al. Covalent and Selective Grafting of Polyethylene Glycol Brushes at the Surface of ZIF-8 for the Processing of Membranes for Pervaporation. ACS Sustain. Chem. Eng. 2019, 7, 6629–6639. [Google Scholar] [CrossRef]
  24. Fazlifard, S.; Allahgholi, N.; Mohammadi, T.; Bakhtiari, O. P84/ZIF-8 mixed matrix membranes for pervaporation dehydration of isopropanol. Desalination Water Treat. 2017, 77, 282–290. [Google Scholar] [CrossRef]
  25. Shi, G.M.; Yang, T.; Chung, T.S. Polybenzimidazole (PBI)/zeolitic imidazolate frameworks (ZIF-8) mixed matrix membranes for pervaporation dehydration of alcohols. J. Membr. Sci. 2012, 415–416, 577–586. [Google Scholar] [CrossRef]
  26. Yin, H.; Lau, C.Y.; Rozowski, M.; Howard, C.; Xu, Y.; Lai, T.; Dose, M.E.; Lively, R.P.; Lind, M.L. Free-standing ZIF-71/PDMS nanocomposite membranes for the recovery of ethanol and 1-butanol from water through pervaporation. J. Membr. Sci. 2017, 529, 286–292. [Google Scholar] [CrossRef]
  27. Zhang, F.; Dou, J.; Zhang, H. Mixed Membranes Comprising Carboxymethyl Cellulose (as Capping Agent and Gas Barrier Matrix) and Nanoporous ZIF-L Nanosheets for Gas Separation Applications. Polymers 2018, 10, 1340. [Google Scholar] [CrossRef]
  28. Rahman, M.S.; Hasan, M.S.; Nitai, A.S.; Nam, S.; Karmakar, A.K.; Ahsan, M.S.; Shiddiky, M.J.A.; Ahmed, M.B. Recent Developments of Carboxymethyl Cellulose. Polymers 2021, 13, 1345. [Google Scholar] [CrossRef]
  29. Araújo, T.; Parnell, A.J.; Bernardo, G.; Mendes, A. Cellulose-based carbon membranes for gas separations—Unraveling structural parameters and surface chemistry for superior separation performance. Carbon 2023, 204, 398–410. [Google Scholar] [CrossRef]
  30. Kalahal, P.B.; Sajjan, A.M.; Yunus Khan, T.M.; Rajhi, A.A.; Achappa, S.; Banapurmath, N.R.; Ashwini, M.; Duhduh, A.A. Novel Polyelectrolyte Complex Membranes Containing Carboxymethyl Cellulose–Gelatin for Pervaporation Dehydration of Azeotropic Bioethanol for Biofuel. Polymers 2022, 14, 5114. [Google Scholar] [CrossRef]
  31. Jo, S.; Chaudhari, S.; Shin, H.; Fitriasari, E.I.; Shon, M.; Nam, S.; Park, Y. Strategies to overcome the limitations of cross-linked hydrophilic PVA membranes; carboxy methyl cellulose blending for epichlorohydrin-isopropanol-water pervaporation dehydration. J. Water Process Eng. 2023, 55, 104101. [Google Scholar] [CrossRef]
  32. Gasemloo, S.; Khosravi, M.; Sohrabi, M.R.; Dastmalchi, S.; Gharbani, P. Response surface methodology (RSM) modeling to improve removal of Cr (VI) ions from tannery wastewater using sulfated carboxymethyl cellulose nanofilter. J. Clean. Prod. 2019, 208, 736–742. [Google Scholar] [CrossRef]
  33. Kuzminova, A.I.; Dmitrenko, M.E.; Poloneeva, D.Y.; Selyutin, A.A.; Mazur, A.S.; Emeline, A.V.; Mikhailovskii, V.Y.; Solovyev, N.D.; Ermakov, S.S.; Penkova, A.V. Sustainable composite pervaporation membranes based on sodium alginate modified by metal organic frameworks for dehydration of isopropanol. J. Membr. Sci. 2021, 626, 119194. [Google Scholar] [CrossRef]
  34. Sales, P.d.T.F.; de Souza, K.M.; Bezerra, A.G.; Ojala, S.A.; de Oliveira, S.B.; Bara, M.T.F. Cálculos químicos quânticos e seus usos. Res. Soc. Dev. 2021, 10, e45910817567. [Google Scholar] [CrossRef]
  35. Keskin, S.; Liu, J.; Rankin, R.B.; Johnson, J.K.; Sholl, D.S. Progress, Opportunities, and Challenges for Applying Atomically Detailed Modeling to Molecular Adsorption and Transport in Metal−Organic Framework Materials. Ind. Eng. Chem. Res. 2009, 48, 2355–2371. [Google Scholar] [CrossRef]
  36. Odoh, S.O.; Cramer, C.J.; Truhlar, D.G.; Gagliardi, L. Quantum-Chemical Characterization of the Properties and Reactivities of Metal–Organic Frameworks. Chem. Rev. 2015, 115, 6051–6111. [Google Scholar] [CrossRef]
  37. Zhang, Y.; Yu, C.; Lü, Z.; Yu, S. Modification of polysulfone ultrafiltration membrane by sequential deposition of cross-linked poly(vinyl alcohol) (PVA) and sodium carboxymethyl cellulose (CMCNa) for nanofiltration. Desalination Water Treat. 2016, 57, 17658–17669. [Google Scholar] [CrossRef]
  38. Baker, R.W. Membrane Technology and Applications; McGraw-Hill: New York, NY, USA, 2000. [Google Scholar]
  39. Baker, R.W.; Wijmans, J.G.; Huang, Y. Permeability, permeance and selectivity: A preferred way of reporting pervaporation performance data. J. Membr. Sci. 2010, 348, 346–352. [Google Scholar] [CrossRef]
  40. Frisch, M.J. Gaussian 16, Revision A.03; Gaussian, Inc., Wallingford CT. 2016. Available online: https://gaussian.com/citation_a03/ (accessed on 18 April 2025).
  41. Becke, A.D. Density-functional thermochemistry. I. The effect of the exchange-only gradient correction. J. Chem. Phys. 1992, 96, 2155–2160. [Google Scholar] [CrossRef]
  42. Becke, A.D. Density-functional exchange-energy approximation with correct asymptotic behavior. Phys. Rev. A 1988, 38, 3098–3100. [Google Scholar] [CrossRef]
  43. Lee, C.; Yang, W.; Parr, R.G. Development of the Colle-Salvetti correlation-energy formula into a functional of the electron density. Phys. Rev. B 1988, 37, 785–789. [Google Scholar] [CrossRef] [PubMed]
  44. Lu, T.; Chen, F. Multiwfn: A multifunctional wavefunction analyzer. J. Comput. Chem. 2012, 33, 580–592. [Google Scholar] [CrossRef] [PubMed]
  45. Johnson, E.R.; Keinan, S.; Mori-Sánchez, P.; Contreras-García, J.; Cohen, A.J.; Yang, W. Revealing Noncovalent Interactions. J. Am. Chem. Soc. 2010, 132, 6498–6506. [Google Scholar] [CrossRef] [PubMed]
  46. Batonneau-Gener, I.; Sachse, A. Determination of the Exact Microporous Volume and BET Surface Area in Hierarchical ZSM-5. J. Phys. Chem. C 2019, 123, 4235–4242. [Google Scholar] [CrossRef]
  47. Walton, K.S.; Snurr, R.Q. Applicability of the BET Method for Determining Surface Areas of Microporous Metal−Organic Frameworks. J. Am. Chem. Soc. 2007, 129, 8552–8556. [Google Scholar] [CrossRef]
  48. Kuzminova, A.; Dmitrenko, M.; Zolotarev, A.; Myznikov, D.; Selyutin, A.; Su, R.; Penkova, A. Pervaporation Polyvinyl Alcohol Membranes Modified with Zr-Based Metal Organic Frameworks for Isopropanol Dehydration. Membranes 2022, 12, 908. [Google Scholar] [CrossRef]
  49. Kuzminova, A.; Dmitrenko, M.; Mazur, A.; Ermakov, S.; Penkova, A. Novel Pervaporation Membranes Based on Biopolymer Sodium Alginate Modified by FeBTC for Isopropanol Dehydration. Sustainability 2021, 13, 6092. [Google Scholar] [CrossRef]
  50. Hidayat, S.; Ardiaksa, P.; Riveli, N.; Rahayu, I. Synthesis and characterization of carboxymethyl cellulose (CMC) from salak-fruit seeds as anode binder for lithium-ion battery. In Proceedings of the 3rd Padjadjaran International Physics Symposium, Bandung, Indonesia, 14–15 November 2017; IOP Publishing Ltd.: Bristol, UK, 2018; Volume 1080, p. 012017. [Google Scholar] [CrossRef]
  51. Hernández, M.; Leyva, G.; Magaña, J.J.; Guzmán-Vargas, A.; Felipe, C.; Lara, V.; Lima, E. New copolymers as hosts of ribosomal RNA. BMC Chem. 2019, 13, 33. [Google Scholar] [CrossRef]
  52. Li, Z.; Cao, Z.; Grande, C.; Zhang, W.; Dou, Y.; Li, X.; Fu, J.; Shezad, N.; Akhtar, F.; Kaiser, A. A phase conversion method to anchor ZIF-8 onto a PAN nanofiber surface for CO2 capture. RSC Adv. 2022, 12, 664–670. [Google Scholar] [CrossRef]
  53. Yáñez-S, M.; Matsuhiro, B.; Maldonado, S.; González, R.; Luengo, J.; Uyarte, O.; Serafine, D.; Moya, S.; Romero, J.; Torres, R.; et al. Carboxymethylcellulose from bleached organosolv fibers of Eucalyptus nitens: Synthesis and physicochemical characterization. Cellulose 2018, 25, 2901–2914. [Google Scholar] [CrossRef]
  54. Duan, J.; Pan, Y.; Pacheco, F.; Litwiller, E.; Lai, Z.; Pinnau, I. High-performance polyamide thin-film-nanocomposite reverse osmosis membranes containing hydrophobic zeolitic imidazolate framework-8. J. Membr. Sci. 2015, 476, 303–310. [Google Scholar] [CrossRef]
  55. Lin, R.; Hernandez, B.V.; Ge, L.; Zhu, Z. Metal organic framework based mixed matrix membranes: An overview on filler/polymer interfaces. J. Mater. Chem. A 2018, 6, 293–312. [Google Scholar] [CrossRef]
  56. Dmitrenko, M.; Kuzminova, A.; Dubovenko, R.; Mikulan, A.; Puzikova, M.; Selyutin, A.; Mazur, A.; Ermakov, S.; Su, R.; Penkova, A. Carboxymethyl cellulose/Zn-based metal organic frameworks membranes for pervaporation-assisted esterification reactor. Sep. Purif. Technol. 2024, 332, 125720. [Google Scholar] [CrossRef]
  57. Dmitrenko, M.; Mikhailovskaya, O.; Dubovenko, R.; Kuzminova, A.; Myznikov, D.; Mazur, A.; Semenov, K.; Rusalev, Y.; Soldatov, A.; Ermakov, S.; et al. Pervaporation Membranes Based on Polyelectrolyte Complex of Sodium Alginate/Polyethyleneimine Modified with Graphene Oxide for Ethanol Dehydration. Polymers 2024, 16, 1206. [Google Scholar] [CrossRef]
  58. Wiberg, K.B. Application of the pople-santry-segal CNDO method to the cyclopropylcarbinyl and cyclobutyl cation and to bicyclobutane. Tetrahedron 1968, 24, 1083–1096. [Google Scholar] [CrossRef]
  59. Trindle, C. Bond index description of delocalization. J. Am. Chem. Soc. 1969, 91, 219–220. [Google Scholar] [CrossRef]
  60. Mayer, I.; Salvador, P. Overlap populations, bond orders and valences for ‘fuzzy’ atoms. Chem. Phys. Lett. 2004, 383, 368–375. [Google Scholar] [CrossRef]
  61. Georgiou, D.C.; Butler, P.; Browne, E.C.; Wilson, D.J.D.; Dutton, J.L. On the Bonding in Bis-pyridine Iodonium Cations. Aust. J. Chem. 2013, 66, 1179. [Google Scholar] [CrossRef]
  62. Naik, P.V.; Bernstein, R.; Vankelecom, I.F.J. Influence of support layer and PDMS coating conditions on composite membrane performance for ethanol/water separation by pervaporation. J. Appl. Polym. Sci. 2016, 133, 43670. [Google Scholar] [CrossRef]
  63. Kattula, M.; Ponnuru, K.; Zhu, L.; Jia, W.; Lin, H.; Furlani, E.P. Designing ultrathin film composite membranes: The impact of a gutter layer. Sci. Rep. 2015, 5, 15016. [Google Scholar] [CrossRef]
  64. Wijmans, J.G.; Hao, P. Influence of the porous support on diffusion in composite membranes. J. Membr. Sci. 2015, 494, 78–85. [Google Scholar] [CrossRef]
  65. Nordin, N.A.H.M.; Ismail, A.F.; Misdan, N.; Nazri, N.A.M. Modified ZIF-8 mixed matrix membrane for CO2/CH4 separation. AIP Conf. Proc. 2017, 1891, 020091. [Google Scholar] [CrossRef]
  66. Kachhadiya, D.D.; Murthy, Z.V.P. Preparation and characterization of ZIF-8 and ZIF-67 incorporated poly(vinylidene fluoride) membranes for pervaporative separation of methanol/water mixtures. Mater. Today Chem. 2021, 22, 100591. [Google Scholar] [CrossRef]
  67. Zhang, Y.; Jia, Y.; Li, M.; Hou, L. Influence of the 2-methylimidazole/zinc nitrate hexahydrate molar ratio on the synthesis of zeolitic imidazolate framework-8 crystals at room temperature. Sci. Rep. 2018, 8, 9597. [Google Scholar] [CrossRef]
  68. Cravillon, J.; Münzer, S.; Lohmeier, S.-J.; Feldhoff, A.; Huber, K.; Wiebcke, M. Rapid Room-Temperature Synthesis and Characterization of Nanocrystals of a Prototypical Zeolitic Imidazolate Framework. Chem. Mater. 2009, 21, 1410–1412. [Google Scholar] [CrossRef]
  69. Ordoñez, M.J.C.; Balkus, K.J.; Ferraris, J.P.; Musselman, I.H. Molecular sieving realized with ZIF-8/Matrimid® mixed-matrix membranes. J. Membr. Sci. 2010, 361, 28–37. [Google Scholar] [CrossRef]
  70. Jomekian, A.; Behbahani, R.M.; Mohammadi, T.; Kargari, A. Innovative layer by layer and continuous growth methods for synthesis of ZIF-8 membrane on porous polymeric support using poly(ether- block -amide) as structure directing agent for gas separation. Microporous Mesoporous Mater. 2016, 234, 43–54. [Google Scholar] [CrossRef]
  71. Mata, I.; Alkorta, I.; Espinosa, E.; Molins, E. Relationships between interaction energy, intermolecular distance and electron density properties in hydrogen bonded complexes under external electric fields. Chem. Phys. Lett. 2011, 507, 185–189. [Google Scholar] [CrossRef]
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Figure 1. The scheme of research.
Figure 1. The scheme of research.
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Figure 2. SEM images of the sample ZIF-8.
Figure 2. SEM images of the sample ZIF-8.
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Figure 3. The pervaporation setup.
Figure 3. The pervaporation setup.
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Figure 4. The dependence of permeation flux on the ZIF-8 content in the CMC matrix in the pervaporation separation of water/isopropanol (12 and 20 wt% water) mixtures.
Figure 4. The dependence of permeation flux on the ZIF-8 content in the CMC matrix in the pervaporation separation of water/isopropanol (12 and 20 wt% water) mixtures.
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Figure 5. FTIR spectra of the dense CMC-0 and CMC-10 membranes.
Figure 5. FTIR spectra of the dense CMC-0 and CMC-10 membranes.
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Figure 6. 13C NMR spectra of ZIF-8, the dense CMC-0, and CMC-10 membranes.
Figure 6. 13C NMR spectra of ZIF-8, the dense CMC-0, and CMC-10 membranes.
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Figure 7. SEM micrographs (cross-sectional and surface) of dense membranes based on CMC and its composites with different concentrations of ZIF-8.
Figure 7. SEM micrographs (cross-sectional and surface) of dense membranes based on CMC and its composites with different concentrations of ZIF-8.
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Figure 8. AFM images and the average roughness (Ra) of the membrane surface of dense membranes based on CMC and its composites with different concentrations of ZIF-8.
Figure 8. AFM images and the average roughness (Ra) of the membrane surface of dense membranes based on CMC and its composites with different concentrations of ZIF-8.
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Figure 9. Thermogravimetric curves for the developed dense CMC-0, CMC-10, and CMC-15 membranes and ZIF-8.
Figure 9. Thermogravimetric curves for the developed dense CMC-0, CMC-10, and CMC-15 membranes and ZIF-8.
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Figure 10. Water contact angles for the developed dense CMC and CMC+ZIF-8 membranes.
Figure 10. Water contact angles for the developed dense CMC and CMC+ZIF-8 membranes.
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Figure 11. QTAIM analysis reveals bond critical points (BCPs, blue spheres) and bond paths for the CMC⋯MIM associates. Non-covalent interaction (NCI) isosurfaces (isovalue 0.5 (e1/3 bohr)−1) are also depicted, colored according to the sign (λ2)ρ range of −0.04 to 0.02 e/bohr3.
Figure 11. QTAIM analysis reveals bond critical points (BCPs, blue spheres) and bond paths for the CMC⋯MIM associates. Non-covalent interaction (NCI) isosurfaces (isovalue 0.5 (e1/3 bohr)−1) are also depicted, colored according to the sign (λ2)ρ range of −0.04 to 0.02 e/bohr3.
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Figure 12. The QTAIM analysis reveals bond critical points (BCPs, blue spheres) and bond paths for the studied associates. Non-covalent interaction (NCI) isosurfaces (isovalue 0.5 (e1/3 bohr)−1) are also depicted, colored according to the sign (λ2)ρ range of −0.04 to 0.02 e/bohr3.
Figure 12. The QTAIM analysis reveals bond critical points (BCPs, blue spheres) and bond paths for the studied associates. Non-covalent interaction (NCI) isosurfaces (isovalue 0.5 (e1/3 bohr)−1) are also depicted, colored according to the sign (λ2)ρ range of −0.04 to 0.02 e/bohr3.
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Figure 13. SEM micrographs of cross-sections at different magnifications of the porous CA, PAN(DMA), and PAN(DMSO) substrates.
Figure 13. SEM micrographs of cross-sections at different magnifications of the porous CA, PAN(DMA), and PAN(DMSO) substrates.
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Figure 14. AFM images and the average roughness (Ra) of the porous CA, PAN(DMA), and PAN(DMSO) substrates.
Figure 14. AFM images and the average roughness (Ra) of the porous CA, PAN(DMA), and PAN(DMSO) substrates.
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Figure 15. (a) Permeation flux and (b) permeate water content as a function of feed water content during the pervaporation of water/isopropanol (12 and 20 wt% water) mixtures for supported membranes.
Figure 15. (a) Permeation flux and (b) permeate water content as a function of feed water content during the pervaporation of water/isopropanol (12 and 20 wt% water) mixtures for supported membranes.
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Figure 16. Cross-sectional and surface SEM micrographs of supported CMC-based and CMC-10/CA membranes.
Figure 16. Cross-sectional and surface SEM micrographs of supported CMC-based and CMC-10/CA membranes.
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Figure 17. AFM images and the average roughness (Ra) of the untreated supported membranes.
Figure 17. AFM images and the average roughness (Ra) of the untreated supported membranes.
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Figure 18. (a) Permeation flux and (b) permeate water content as a function of feed water content during the pervaporation of water/isopropanol (12 and 20 wt% water) mixtures for cross-linked supported membranes.
Figure 18. (a) Permeation flux and (b) permeate water content as a function of feed water content during the pervaporation of water/isopropanol (12 and 20 wt% water) mixtures for cross-linked supported membranes.
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Table 1. Developed dense and supported membranes based on the CMC and CMC+ZIF-8 composites.
Table 1. Developed dense and supported membranes based on the CMC and CMC+ZIF-8 composites.
MembraneTypeContent of
ZIF-8,
wt%		SupportCross-Linking
CMC-0dense0--
CMC-5dense5--
CMC-10dense10--
CMC-15dense15--
CMC-0/CAsupported0CA-
CMC-0/PAN(DMA)supported0PAN(DMA)-
CMC-0/PAN(DMSO)supported0PAN(DMSO)-
CMC-10/CAsupported10CA-
CMC-0/CACLsupported0CA+
CMC-10/CACLsupported10CA+
Table 2. Swelling degree in water/isopropanol mixture for the developed dense CMC and CMC+ZIF-8 membranes.
Table 2. Swelling degree in water/isopropanol mixture for the developed dense CMC and CMC+ZIF-8 membranes.
MembraneSwelling Degree in Water/Isopropanol (12/88 wt%), %
CMC-05.8
CMC-58.1
CMC-109.9
CMC-1510.9
Table 3. Change in isothermal–isobaric potential during the formation of the most energetically favorable associates.
Table 3. Change in isothermal–isobaric potential during the formation of the most energetically favorable associates.
ΔG0, (kJ/mol)
B3LYP/6-311++G**MIMi-PrOHH2O
1-CMC−146.5−0.7−1.0
2-CMC−148.94.11.8
3-CMC−155.00.41.4
MIM~−32.4−32.3
i-PrOH ~10.7
Table 4. Information about the interaction geometry, including the distances between interacting atoms, the ratio of these distances to the sum of the van der Waals radii, and the corresponding WBI and FBO.
Table 4. Information about the interaction geometry, including the distances between interacting atoms, the ratio of these distances to the sum of the van der Waals radii, and the corresponding WBI and FBO.
B3LYP/6-311++G**
AssociateInteractionWBIFBOd, ÅR, %
1-CMCMIMO(CO*OH)///H(CH3)0.0420.0492.3766987.4%
H(COOH)//N0.8560.6911.0388837.8%
O(COO*H)///H(COOH)0.0890.0941.7827365.5%
i-PrOHO(CO*OH)///H(OH)0.0480.0392.2179181.5%
H(COOH)///O0.1850.1221.6803861.8%
O(OH)///H(CH3)0.0050.0093.25592119.7%
H2OO(CO*OH)///H0.0720.0542.0602575.7%
H(COOH)///O0.1540.1161.7493964.3%
2-CMCMIMO(CO*OH)///H(CH3)0.0300.0362.5809194.9%
H(COOH)//N0.8420.6701.0473438.1%
O(COO*H)///H(COOH)0.1890.1301.6868262.0%
i-PrOHH(CH2*OH)///H(CH3)0.0020.0023.15786116.1%
O(CH2OH)///H(OH)0.0900.0741.9457871.5%
H2OO(CO*OH)///H0.0680.0522.0783876.4%
H(COOH)///O0.1430.1091.7681865.0%
3-CMCMIMO(COO*H)///H(COOH)0.1850.1271.7015762.6%
H(COOH)//N0.8410.6701.0472438.1%
i-PrOHO(CO*OH)///H(OH)0.0510.0412.1873280.4%
H(COOH)///O0.1650.1121.7100662.9%
H2OO(CO*OH)///H0.0680.0522.0758476.3%
H(COOH)///O0.1440.1101.7664364.9%
MIMi-PrOHN///H(OH)0.2140.1471.7374363.2%
H2ON///H0.1840.1461.7468363.5%
IPAH2OO///H0.1080.0811.885769.3%
Table 5. Porosity characteristics of porous CA, PAN-(DMA), and PAN(DMSO) substrates.
Table 5. Porosity characteristics of porous CA, PAN-(DMA), and PAN(DMSO) substrates.
Porosity CharacteristicsPorous Support
CAPAN(DMA)PAN(DMSO)
Porosity over weight (cm3/g)2.02.54.9
Porosity over volume (cm3/cm3)0.80.90.9
Meso- and macro-pore surface over weight (m2/g)30.161.284.0
Meso- and macro-pore surface over volume (m2/cm3)12.220.915.8
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Kuzminova, A.; Dmitrenko, M.; Dubovenko, R.; Mikulan, A.; Stepanova, A.; Puzikova, M.; Rakovskaya, N.; Mazur, A.; Shurukhina, A.; Rudakova, A.; et al. Sustainable Novel Membranes Based on Carboxymethyl Cellulose Modified with ZIF-8 for Isopropanol/Water Pervaporation Separation. Sustainability 2025, 17, 3801. https://doi.org/10.3390/su17093801

AMA Style

Kuzminova A, Dmitrenko M, Dubovenko R, Mikulan A, Stepanova A, Puzikova M, Rakovskaya N, Mazur A, Shurukhina A, Rudakova A, et al. Sustainable Novel Membranes Based on Carboxymethyl Cellulose Modified with ZIF-8 for Isopropanol/Water Pervaporation Separation. Sustainability. 2025; 17(9):3801. https://doi.org/10.3390/su17093801

Chicago/Turabian Style

Kuzminova, Anna, Mariia Dmitrenko, Roman Dubovenko, Anna Mikulan, Anastasia Stepanova, Margarita Puzikova, Nadezhda Rakovskaya, Anton Mazur, Anna Shurukhina, Aida Rudakova, and et al. 2025. "Sustainable Novel Membranes Based on Carboxymethyl Cellulose Modified with ZIF-8 for Isopropanol/Water Pervaporation Separation" Sustainability 17, no. 9: 3801. https://doi.org/10.3390/su17093801

APA Style

Kuzminova, A., Dmitrenko, M., Dubovenko, R., Mikulan, A., Stepanova, A., Puzikova, M., Rakovskaya, N., Mazur, A., Shurukhina, A., Rudakova, A., Emeline, A., Su, R., & Penkova, A. (2025). Sustainable Novel Membranes Based on Carboxymethyl Cellulose Modified with ZIF-8 for Isopropanol/Water Pervaporation Separation. Sustainability, 17(9), 3801. https://doi.org/10.3390/su17093801

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