Porous Hollow Fiber Research Articles

Engineering Interfacial Molecular Interactions on Ag Hollow Fibre Gas Diffusion Electrodes for High Efficiency in CO2 Conversion to CO.

The electrochemical CO2 reduction reaction (CO2RR) occurs at the nanoscale interface of the electrode-electrolyte. Therefore, tailoring the interfacial properties in the interface microenvironment provides a powerful strategy to optimise the activity and selectivity of electrocatalysts towards the desired products. Here, the microenvironment at the electrode-electrolyte interface of the flow-through Ag-based hollow fibre gas diffusion electrode (Ag HFGDE) is modulated by introducing surfactant cetyltrimethylammonium bromide (CTAB) as the electrolyte additive. The porous hollow fibre configuration and gas penetration mode facilitate the CO2 mass transfer and the formation of the triple-phase interface. Through the ordered arrangement of hydrophobic long-alkyl chains, CTAB molecules at the electrode/electrolyte interface promoted CO2 penetration to active sites and repelled water to reduce the activity of competitive hydrogen evolution reaction (HER). By applying CTAB-containing catholyte, Ag HFGDE achieved a high CO Faradaic efficiency (FE) of over 95 % in a wide potential range and double the partial current density of CO. The enhancement of CO selectivity and suppression of hydrogen was attributed to the improvement of charge transfer and the CO2/H2O ratio enhancement. These findings highlight the importance of adjusting the local microenvironment to enhance the reaction kinetics and product selectivity in the electrochemical CO2 reduction reaction CO2RR.

A novel TFNi pervaporation membrane with g-C3N4 quantum dots for high-efficiency IPA dehydration

Pervaporation (PV) shows significant potential for the highly selective isopropanol (IPA). The pursuit of developing PV membranes with outstanding separation effect and enduring high purity permeation is an indispensable goal. Based on polyamide (PA) separation layers, a polydopamine (PDA) mixed g-C3N4 quantum dots (gCNQDs) coating as the interlayer was deposited onto a porous ceramic hollow fiber substrate to fabricate thin-film nanocomposite membranes with an interlayer (TFNi). The nanocomposite interlayer enabled the formation of a smoother and highly separated selective polyamide layer. The separation factor exhibited a 31-fold enhancement with the augmentation of the blending fraction of gCNQDs during the PDA coating process. The resulting TFNi membrane attained an exceedingly high separation factor of 10270 ± 90 with a permeate water concentration of 99.9% and demonstrated a satisfactory flux of 1.40 ± 0.08 kg⋅m-2⋅h-1 during the PV process of 90 wt% IPA dehydration at 60 °C. This study presents a fresh perspective on the implementation of nanocomposite interlayers, which is expected to expand the application of high-performance TFNi membranes in PV dehydration processes.

Optimization of hollow fiber membrane contactor system for CO2 mineralization using seawater brine: Comparative analysis of performance and transport mechanisms

Carbon mineralization is a promising approach for carbon capture, utilization, and storage (CCUS) but still faces technical and economic challenges. This study reports on CO2 mineralization using various hollow fiber membrane contactors (HFMCs) to optimize the system and understand the mass transport mechanism. We conducted a quantitative comparative assessment through theoretical and experimental approaches to evaluate the performance of three HFMC types with different morphological and chemical characteristics at various gas and liquid velocities. Results showed that the in-house developed highly porous hollow fiber (HF) membrane exhibited superior CO2 capture efficiency compared to commercial membranes. In contrast to other HFMCs showing a sharp decline in CO2 flux due to internal fouling caused by pore wetting and external fouling, the highly porous HF membrane with surface modification maintained stable performance during continuous operation due to its superhydrophobicity and surface roughness. The HF membrane also achieved the highest overall mass transfer coefficients, closely matching the theoretical non-wetted mode due to negligible partial wetting. We expect that this study will provide insights into optimizing HFMCs for enhanced carbon mineralization efficiency.

Boosting the H2/CO2 and H2/N2 selectivities of a graphene oxide membrane by shrinking the membrane interlayer spacing via thermal treatment

Graphene oxide (GO) membranes have been widely studied and used for gas separation processes, but some structural changes are necessary to guarantee high membrane selectivities. The thermal reduction process stands out for reducing the interlayer channel size of the GO nanosheets to improve the molecular sieving mechanism. Herein, thermally annealed GO layers were deposited on the outer surface of porous alumina hollow fiber substrates and the produced composite membranes were tested for selective hydrogen (H2) separations. The influence of the thermal annealing process at different mild temperatures (80 and 160 °C) on the characteristics of the GO structure was investigated towards the improvement of the membrane efficiency for H2 separation. ATR-FTIR results confirmed the elimination of oxygenated groups, and XRD analyses showed the GO interlayer space decreased from 8.71 to 7.38 Å after the thermal annealing process at 160 °C. The GO thermally annealed membrane presented an H2 permeance of 2032.47 ± 101.69 GPU and an H2/N2 selectivity of 12.16 ± 0.30, which is 315% greater than the selectivity of the pristine GO membrane. Hence, the application of the thermal reduction method to produce GO membranes with greater selectivities is a viable alternative to deal with gas separation processes.

Fabrication of a high-performance MOF-COP-based porous hollow fiber membrane for carbon dioxide separation

A thin-film nanocomposite (TFNC) hollow fiber membrane with high CO2 permeability and selectivity was synthesized for the separation of carbon dioxide, a major greenhouse gas. A highly porous polyethersulfone (PES) hollow fiber membrane support with a porous structure was first fabricated using heat and pressure treatments, and a thin film was prepared via interfacial polymerization by reacting polyethylenimine (PEI) with 1,3,5-benzenetricarbonyl trichloride (TMC) on the surface of the PES support. A metal–organic framework (MOF)-covalent organic polymer (COP) complex, obtained via polycondensation between an UiO-66-NH2 based MOF and a piperazine- and cyanuric chloride-based COP, was then added to the TFNC to prepare the mixed matrix membrane. The complex contributed to reducing defects between the porous support and the coating layer and additionally led to high CO2 permselectivity by providing a CO2 permeation pathway within the support. The newly prepared TFNC hollow fiber membrane contributed to its excellent separation performance, as evidenced by a CO2 permeability of 352 GPU and a CO2/N2 ideal selectivity of 75 after optimization of the MOF-COP content.

Core-sheath PVDF hollow porous fibers via coaxial wet spinning for energy harvesting

Flexible piezoelectric nanogenerators (PENGs), as a promising sustainable power source in smart electronics, have attracted much attention for their potential applications in the Internet of Things. In this paper, poly(vinylidene fluoride) (PVDF) fibers with core-sheath hollow porous structure were prepared by coaxial wet spinning process, serving as the dielectric layer, which were perfused internally by liquid metal (LM) as the inner electrode layer and wrapped outside by copper-silver nanoparticles (Cu@AgNP) as the outer electrode layer, thus constructing high-performance PVDF/LM/Cu@AgNP composite fibers. The composite PVDF fibers have a layered pore structure and arbitrarily deformable LM electrodes, which can significantly reduce the effective electric constant and thus enhance the piezoelectric properties. The results reveal that PVDF/LM/Cu@AgNP-PENG yields an optimal voltage output of 410 mV, providing a clear advantage over PENG by using alternative fibers. Moreover, the PVDF/LM/Cu@AgNP-PENG shows an excellent charging capability for energy storage devices, being able to charge 1 μF capacitors to 10 V within 30 s and directly power commercial LEDs. This study demonstrates the significant potential for utilizing composite PVDF piezoelectric fibers in flexible wearable electronic devices.

Electromembrane Extraction of Ofloxacin from Human Plasma and Its Quantification by Capillary Electrophoresis

Background: Application of electromembrane extraction coupled with capillary electrophoresis was studied for ofloxacin extraction from plasma samples. Methods: Ofloxacin migrated from acidic plasma samples through a thin layer of 1-octanol immobilized in the pores of a porous hollow fiber wall into a 10 µL acidic aqueous acceptor solution located inside the lumen of the fiber. Results: Under optimum conditions influencing electromigration (i.e., 20 min of the operation time, stirring speed of 750 rpm, donor phase pH at 4.0, acceptor pH at 3.0, and applied voltage of 30 V across the supported liquid membrane), ofloxacin was extracted from plasma samples with an enrichment factor of 100-fold corresponding to extraction percent of 24%. The calibration curve showed acceptable linearity in the range of 0.2-7.0 µg.mL-1 (R=0.9993). The limits of detection and quantification of 0.05 and 0.2 µg.mL-1 were obtained, respectively. The inter- and intra-day precision and accuracy were obtained below 8.65%. Conclusion: The validated method was successfully processed for the ofloxacin determination in the plasma samples of patients under ofloxacin therapy. There were no interfering peaks which indicates the great selectivity of the developed method.

High performance Ce0.8Nd0.2O2-δ-carbonate hollow fiber membrane for high-temperature CO2 separation

Ceramic-carbonate dual phase (CCDP) membrane consisting of oxygen ionic conductor and molten carbonate has potential applications in clean energy delivery as it enabling the direct CO2 separation or capture at the elevated temperatures. The performance of previous CCDP membranes is not ideal either with a low CO2 flux or with a poor operational stability. In the present work, we looked at the CeO2-based oxygen ionic conductor (neodymium doped cerium (NDC)) as the porous ceramic hollow fiber support to form NDC-carbonate hollow fiber membranes. The NDC hollow fiber was fabricated by the combined phase inversion and sintering techniques and the preparation conditions were optimized to better accommodate the carbonate phase and maintain the mechanical stability. The NDC hollow fibers possessed good bending strength, reaching 91.5 MPa upon sintering at 1500 °C. The effects of feed gas composition and sweep flow rates on the CO2 separation performance were carefully investigated. The resultant dual phase hollow fiber membranes exhibited appreciably high CO2 permeation fluxes at temperatures exceeding 800 °C, which was required to activate both conductions of oxygen and carbonate ions. The achieved maximum CO2 flux of the optimized NDC-carbonate hollow fiber membranes was up to 5.08 mL min−1 cm−2 with 50%CO2–50%N2 as the feed gas at 900 °C. At 700 °C, the membrane exhibited a relatively stable CO2 permeation behavior over 120 h and the spent membrane maintained a stable structure. The high flux and good operational stability of the developed membrane make a huge step towards practical applications.

Carbon Molecular Sieve Membranes with Ultra‐Thin Selective Skin Layer by Pyrolysis of Porous Hollow Fibers (Small 20/2024)

Carbon Molecular Sieve Membranes with Ultra‐Thin Selective Skin Layer by Pyrolysis of Porous Hollow Fibers (Small 20/2024)

Modeling of dual-skin asymmetric hollow fiber microporous membranes for predicting the skins parameters separately using gas permeation test

This study presented a comprehensive gas permeation model to predict the skin parameters of a complex system, specifically a hollow fiber membrane with an asymmetric structure consisting of two external and internal skin layers. According to the work of Haefer for n segments of pores connected in series as in hollow fiber membranes, applying the Wakao et al. model, a comprehensive model for the transition regime was derived. The model was examined against the various fabricated PES and PEI hollow fiber membranes. Unlike conventional models, the proposed method predicted the mean pore size and mean pore length independent of surface porosity for each skin layer. The study revealed valuable insights into i) the middle pressure, ii) the difference between the skin parameters of the two membrane skins, and iii) the impact of the feeding direction on gas permeation behavior. It was shown that the dependency of permeation behavior on the feeding direction is linked to the influence of middle pressure on viscous flow, which is closely related to surface porosities of each side. It is evident that even the slightest variations in the fabrication parameters can result in different structures. Furthermore, it is evident that the assumption of neglecting slip flow was reasonable within the experienced Knudsen number range. The model also highlighted that the skin parameters of the two skin layers may not be identical, a distinction not captured by the current models. The traditional approach of setting the middle pressure as the average of the upstream and downstream pressures has been improved by expressing it as a linear function of both pressures. In the feed side, higher pressures led to dominant viscous flow, whilst the permeate side was more influenced by the free molecular regime due to lower pressures. There existed a competition between the Knudsen flow and the viscous flow at a specific Knudsen number for the feeding side pores, whether it was the inner or outer surface. The finding emphasized the significance of porosity values on each side in determining the proximity of middle pressure to feed and permeate side pressures, underscoring the importance of accurate knowledge of surface porosities, mean pore sizes, and pore lengths for both skin layers in understanding processes involving porous dual-skin hollow fiber membranes.

A new coaxial flow-through probe for electromembrane extraction of methadone from clinical samples on-line coupled to capillary electrophoresis

BackgroundA new design of a flow-through coaxial electromembrane extraction (EME) probe that can be on-line coupled with CE instrument is described and tested. The supporting base of the probe is a PDMS microchip with T-shaped channels into which two coaxially arranged capillaries for inlet and outlet solutions are inserted. The extraction part of the probe is a porous polypropylene hollow fiber, sealed at one end and modified with nitrophenyloctyl ether (NPOE) extraction fluid. The internal volume of the extraction probe is 1.1 μL. ResultsThe EME probe was tested on laboratory samples and methadone was extracted into 3.0 M AcOH as acceptor. The concentration dependence was linear in the range of 0.1–1.0 μg mL−1 at EME 300 s/150 V and in the range of 0.5–10.0 μg mL−1 at EME 100 s/150 V. The enrichment factor was greater than 30 and the LOD was 0.21 μg mL−1. The EME of methadone in clinical samples showed a linear concentration dependence in human urine and a nonlinear concentration dependence in serum. The distribution of methadone in each phase of the extraction system and the effect of extraction membrane thickness on the enrichment factor were studied. The EME probe can be applied repeatedly. SignificanceThe supporting base of EME probe and flow gating interface (FGI) are realized by a microfluidic PDMS microchips cast in the laboratory without the use of lithography. A supporting PDMS chip with coaxially arranged capillaries and extraction membrane forms a compact analytical instrument. The entire EME/CE analysis process is performed on a laboratory-made instrument and automated by LabView.

Carbon Molecular Sieve Membranes with Ultra-Thin Selective Skin Layer by Pyrolysis of Porous Hollow Fibers.

Translating carbon molecular sieve (CMS) membranes into highly scalable hollow fiber geometry with ultra-thin selective layer (<1µm) for gas separation remains as great challenge. The porous support layer of precursor hollow fiber membranes is prone to collapse during pyrolysis, which induces thick skin layer (15-50µm) of CMS hollow fiber membranes. Here, a novel strategy is present to obtain an ultra-thin selective skin layer by carbonization of hollow fiber membranes with porous skin. P84-based defect-free CMS hollow fiber membranes with ultra-thin selective skin layer (0.9µm) for gas separation are prepared without any coating or complex chemical pretreatment. Compared with the carbon membranes derived from defect-free fibers, the H2 permeance (93.9 GPU) of CMS membranes derived from the porous fibers increases ≈1353% with comparable selectivity of H2/CH4 (143) and higher H2/N2 (120). Furthermore, the porous fibers are pre-aged near the Tg in N2 conditions before carbonization, and the H2 permeance of the derived CMS hollow fiber membranes reached 147 GPU (increased 2180%). It is a new facile way to prepare CMS hollow fiber membranes with ultra-thin selective layer by porous fibers, demonstrating its versatile potential in gas separation or organic liquids separation.

Coupling metal organic frameworks nanozyme with carbon nanotubes on the gradient porous hollow fiber membrane for nonenzymatic electrochemical H2O2 detection

In this paper, we present a gradient porous hollow fiber structure integrated the signal transduction within a microspace, serving as a platform for cellular metabolism monitoring. We developed a nonenzymatic electrochemical electrode by coupling carbon nanotubes (CNT) and metal organic frameworks (MOF) nanozyme on three-dimensional (3D) gradient porous hollow fiber membrane (GPF) for in-situ detection of cell released hydrogen peroxide (H2O2). The GPF was used as a substrate for cell culture as well as the supporting matrix of the working electrode. The ultrasonically coupled CNT@MOF composite was immobilized on the outer surface of the GPF by means of pressure filtration. Notably, the MOF, acting as a peroxidase mimic, exhibits superior stability compared to traditional horseradish peroxidase. The incorporation of CNT not only provided sufficient specific surface area to improve the uniform distribution of MOF nanozyme, but also formed 3D conductive network. This network efficiently facilitates the electrons transfer during the catalytic process of the MOF, addressing the inherent poor conductivity of MOFs. The GPF-CNT@MOF nonenzymatic bioelectrode demonstrated excellent electrocatalytic performance including rapid response, satisfactory sensing selectivity, and attractive stability, which enabled the development of a robust in-situ cellular metabolic monitoring platform.

Modular coupling MOF nanozyme with natural enzyme on hollow fiber membrane for rapid and reusable detection of H2O2 and glucose.

A novel strategy based on gradient porous hollow fiber membrane (GPF) is proposed for the modular assembly of enzyme-nanozyme cascade systems. The porous structure of GPF provided sufficient specific surface area, while the gradient structure effectively minimized the leaching of enzymes and nanozymes. To enhance stability, we prepared and immobilized metal-organic framework (MOF) nanozymes, resulting in the fabrication of GPF-MOF with excellent stability and reusability for colorimetric H2O2 detection. To improve specificity and expand the detection range, micro-crosslinked natural enzymes were modularly assembled, using glucose oxidase as the model enzyme. The assembled system, GPF-mGOx@MOF, achieved a low detection limit of 0.009mM and a linear range of 0.2 to 11mM. The sensor retained 87.2% and 80.7% of initial activity after being stored for 49 days and 9 recycles, respectively. Additionally, the reliability of the biosensor was validated through glucose determination of human blood and urine samples, yielding comparable results to a commercial glucose meter.

Alkadiyne-Pyrene Conjugated Frameworks with Surface Exclusion Effect for Ultrafast Seawater Desalination.

Billions of populations are suffering from the supply-demand imbalance of clean water, resulting in a global sustainability crisis. Membrane desalination is a promising method to produce fresh water from saline waters. However, conventional membranes often encounter challenges related to low water permeation, negatively impacting energy efficiency and water productivity. Herein, we achieve ultrafast desalination over the newly developed alkadiyne-pyrene conjugated frameworks membrane supported on a porous copper hollow fiber. With membrane distillation, the membrane exhibits nearly complete NaCl rejection (>99.9%) and ultrahigh fluxes (∼500 L m-2 h-1) from the seawater salinity-level NaCl solutions, which surpass the commercial polymeric membranes with at least 1 order of magnitude higher permeability. Experimental and theoretical investigations suggest that the large aspect ratio of membrane pores and the high evaporation area contribute to the high flux, and the graphene-like hydrophobic surface of conjugated frameworks exhibits complete salt exclusion. The simulations also confirm that the intraplanar pores of frameworks are impermeable for water and ions.

Supramolecular Solvent-Based Vortex-Assisted Hollow Fibre Liquid-Phase Microextraction Technique Combined With High Performance Liquid Chromatography for the Determination of Estrogens in Milk Samples

A fast, simple, environmental friendly and strong sample clean-up ability method for the determination of three estrogens (17β-estradiol (17β-E2), estrone (E1), and diethylstilbestrol (DES)) in milk samples has been developed by using supramolecular solvent-based vortex-assisted hollow fibre liquid-phase microextraction (SS-VA-HF-LPME) and high performance liquid chromatography. Method is based on estrogens was extracted from aqueous samples into a supramolecular solvent which were made up of n-octanol and ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM] BF4) impregnated in the wall pores and also filled inside the porous polypropylene hollow fiber membrane followed by vortex-mixing. The supramolecular solvent has better compatibility with the polarity of target analytes and the driving forces for the extraction include hydrogen bonding, hydrophobic and π-cation interactions between the analytes and the vesicular aggregates, thereby leading to high recoveries. Vortex can provide mild and effective mixing of sample solution and increase the contact between analytes and boundary layers of the hollow fibre. Therefore the mass transfer rate was enhanced. The parameters that affect the recoveries were studied and optimized. HF of 4 cm length was used and the pH 4.0 was employed. The percentages of n-octanol and [BMIM]BF4 were 10% and 3%, respectively. The extraction equilibrium time was 4 min. The method provided good linearity (andgt;0.998), repeatability (RSD% = 1.24–4.36), low detection limit (0.10–0.22 ng mL−1), and high enrichment factor (330).

Development of novel composite polydecylmethylsiloxane hollow fiber membranes on highly permeable polysulfone support for С&lt;sub&gt;2+&lt;/sub&gt;/С&lt;sub&gt;1&lt;/sub&gt; separation

A novel composite hollow fiber membrane has been developed for the separation of C2+ hydrocarbons from their mixture with methane. A high-performance porous polysulfone hollow fiber support was fabricated. Polydecylmethylsiloxane (PDecMS) and polydimethylsiloxane (PDMS) were used as a thin selective layer. Comparison of the results of separation of binary mixture of CH4 and C4H10 using PDecMS/PSF and PDMS/PSF membranes showed that for the PDecMS/PSF module the specific retentate flux and n-butane concentration in the permeate are 1.7 times higher and energy consumption is 9 times lower.

ZIF-8-90 @ graphene oxide reinforced porous hollow fiber coupled with deep eutectic solvent for hollow fiber solid-phase microextraction of selected phthalate esters followed by quantification through high-performance liquid chromatography-ultraviolet detection

The present study was conducted to synthesize hybrid MOFs with a high effective surface area consisting of ZIF-8 and ZIF-90 on the surface of Graphene Oxide (GO). The hybrid ZIF-8-90@GO was finally placed inside the Hollow Fiber (HF) pores to use the substrate filtration properties. Then, the extraction device was used to extract three selected phthalate esters including DiMethyl Phthalate (DMP), DiEthyl Phthalate (DEP) and DiButyl Phthalate (DBP) (as the model analytes) followed by back extraction using Deep Eutectic Solvent (DES). Herein, the DES was utilized as a suitable and effective alternative to common toxic desorption solvents, and it led to the greening of the method. In order to achieve maximum efficiency and sensitivity, the parameters influencing on extraction and desorption processes were optimized. In the obtained optimum situation, the method linearity, Limits Of Detection (LODs), Limits Of Quantification (LOQs), Relative Standard Deviations (RSDs%), Enrichment Factors (EFs) were equal to 0.1–500 µg/L, 0.026–0.058 µg/L, 0.089–0.194 µg/L, 1.8 to 4.7% and 45.4–47.1, respectively. The obtained coefficients of determination (r2) were also higher than 0.9990. The Extraction Recovery (%ER) values were also 90, 87 and 91%, respectively for DMP, DEP and DBP. The above-mentioned method was used for the analysis of water and juice samples and acceptable results were obtained. The obtained relative recoveries in the real samples were in the range of 90–103%. Moreover, due to the presence of aldehyde and methyl groups with hydrophilic and hydrophobic properties in the structure of the synthesized hybrid sorbent, the possibility of interaction increased between sorbent and the studied species, and it per se, led to the increase of extraction efficiency.

The role of solvent temperature and gas pressure on CO2 mass transfer during biogas upgrading within porous and dense-skin hollow fibre membrane contactors

Biogas upgrading uniquely requires pressurisation of hollow fibre membrane contactors (HFMC) to be competitive with classical water absorption, and when complemented with an ambient industrial temperature range, these conditions will determine CO2 mass transport phenomena that are distinct dependent upon whether microporous or nonporous membranes are used. This study therefore examines the independent and concomitant role of temperature and pressure in determining CO2 mass transport, and selectivity, within microporous and nonporous HFMC. At low solvent temperatures, higher CO2 flux was achieved which indicates that solvent solubility is more critical than CO2 diffusivity to enhancing mass transport. Low temperatures also favoured mass transfer within the microporous membrane, explained by the reduction in solvent vapour pressure which limited pore wetting by condensation. In contrast, the nonporous membrane exhibited poorer mass transfer at low temperatures due to a decline in dense polymer permeability. Crucially in this study, neither wetting of the microporous membrane or plasticisation of the nonporous membrane were observed following pressurisation. Consequently, CO2 flux increased in proportion to the applied pressure for both membrane types, emphasising the critical role of pressurisation in augmenting process intensification for biogas upgrading which is typically facilitated at pressures of 7–10 bar. Resistance-in-series analysis illustrated how pressurisation reduced gas-phase resistance, and subsequently enhanced selectivity. Consequently, an outlet gas quality of 98% methane could be achieved within a single microporous module at 4.5 bar, meeting the industrial standard for biomethane whilst reducing solvent requirements, separation energy and methane losses. Comparable behaviour was observed during pressurisation of the nonporous membrane, but with a less significant benefit to CO2 mass transfer and selectivity, ostensibly due to the resistance imparted by the dense polymer. When considered collectively, low solvent temperature and high gas pressure enhance process intensification subsequently reducing process size (e.g., membrane area) and separation energy, while also advancing selectivity to deliver a gas product at the composition required for biomethane with minimum methane losses, which are critical factors in demonstrating microporous HFMC as an industrially competitive solution for biogas upgrading.

A profound investigation into the viability of calcium bentonite as a new alternative ceramic material for the development of a highly porous ceramic hollow fiber membrane for the remediation of oily produced water

BackgroundCeramic hollow fiber membranes (CHFMs) have been recognized as an effective method in treating oily produced water (OPW). However, the high cost of CHFMs deters industries for implementing them on a large scale. MethodsThis research investigates the feasibility of using calcium bentonite as CHFMs for treating OPW and examines the effect of sintering temperatures on the physical properties, mechanical properties and performance of calcium bentonite hollow fiber membranes (CaB-HFMs). The calcium bentonite undergoes several pre-treatment processes and is subsequently characterized. The fabricated CaB-HFM with 45 wt% of calcium bentonite content (CaB-HFM 45) is characterized and examined for water permeation and OPW rejection performance in a cross-flow filtration mode for 3 h. Significant findingAmong the CaB-HFM 45, the membrane sintered at 1100 °C displayed optimum characteristics for OPW treatment, including a good morphology with adequate sponge-like and void-like pore structure, a mechanical strength of 95.33 ± 2.6 MPa, an average pore size of 1.015 µm and a porosity of 51.04%. Surprisingly, the membrane also displayed strong hydrophilic behavior (26.05°) and strong underwater oleophobic behavior (141.20°), resulting in outstanding water permeation performance (505.7 ± 29.5 L/m2.h.bar) and oil rejection performance of up to 97%. These remarkable features highlight the membrane's potential as a promising solution for OPW treatment.