Non-solvent Induced Phase Separation Research Articles

Electrospun polycaprolactone/graphene oxide scaffolds with secondary surface porosity and gelatin-coating

Polycaprolactone (PCL) is a versatile and biodegradable synthetic polymer widely used in tissue regeneration applications owing to its versatility and mechanical properties. In this study, we employed a three-level strategy to develop innovative PCL-based scaffold biomaterials using electrospinning. First, we incorporated graphene oxide (GO); second, we introduced secondary surface porosity (SSP) through non-solvent induced phase separation (NIPS) with a diameter of approximately 2 μm; and third, we applied a gelatin coating (Gt). The inclusion of GO resulted in both a reduction in fiber size and a decrease in the size of the secondary surface pores formed on the fibers. Additionally, the incorporation of GO led to a noteworthy 20-fold increase in gelatin adhesion compared to pure SSP-PCL scaffolds. However, the mechanical properties of the gelatin-coated scaffolds exhibited a decrease compared to the uncoated scaffolds. This reduction is primarily attributed to the decrease in crystallinity in coating gelatin scaffold. Furthermore, GO and gelatin played critical roles in enhancing biodegradation and bioactivity, promoting hydroxyapatite formation on the surface of SSP-PCL scaffolds. In vitro cell viability tests demonstrated the cytocompatibility of PCL, PCL/Gt, and PCL/Gt/GO electrospun SSP scaffolds, facilitating the adhesion of human mesenchymal stem cells. Our study introduces an innovative strategy for fabricating PCL scaffolds through electrospinning, incorporating SSP for improved gelatin adsorption, and holds great promise for tissue engineering applications.

Superhydrophobic finishing of cotton fabric via nonsolvent-induced phase separation of polystyrene–perfluoropolyether block copolymer

This paper reports synthesis of polystyrene–perfluoropolyether block copolymer@cotton fabric (PS–PFPE@CF) with a rough structure through nonsolvent-induced phase separation. The factors affecting the hydrophobicity of the coating, such as solvent quality, the molecular weight of the PS segments, and the volume ratio of tetrahydrofuran/1,3-di(trifluoromethyl)benzene (THF/DTFMB) and THF–MeOH, were all investigated, and the relation between the coating structure and hydrophobicity was also analyzed. In the THF–DTFMB system, PS–PFPE@CF (4 h, 80 mg/mL) appeared as a secondary structure with the superposition of small spheres on large spheres. For this structure, the water-contact angle reached 156.2° ± 0.5° and the sliding angle was 9.5° ± 1.5°. Furthermore, scanning electron microscopy, energy-dispersive X-ray spectroscopy, atomic force microscopy, and thermogravimetric analysis confirmed that PS–PFPE coated the cotton fabric. Finally, application tests were performed to assess the application prospects of PS–PFPE@CF. Oil-water separation, self-cleaning, and antifouling applications were studied, and the experimental results showed that the separation efficiency of the superhydrophobic fabric was nearly constant, from 99.4 % to 98.3 % after 10 oil-water separation tests. PS–PFPE@CF exhibited excellent self-cleaning properties and performed well in the sandpaper abrasion and tape peeling tests. This research thus used a degradable PFPE block copolymer to produce cotton fabrics with excellent hydrophobicity, self-cleaning, and wear resistance.

Facile fabrication of regenerated cellulose-based separators for high-performance lithium-ion batteries by regulating degrees of polymerization

Cellulose-based separators have great application prospects in the field of lithium-ion batteries (LIBs) due to their excellent wettability and thermal stability. However, most current cellulose-based separators come from high-cost nanocellulose and bacterial cellulose. Herein, regenerated cellulose (RC) separators were prepared from dissolving pulp with different degrees of polymerization (DPs) by using the NaOH/urea/thiourea dissolution system as well as a nonsolvent-induced phase separation method. The results showed that the DP of cellulose had a significant influence on the mechanical properties, pore structure, and electrochemical properties of the resultant RC separator. An appropriate increase in the DP could improve the mechanical strength, porosity, and ionic conductivity of the separator. The RC separator with a DP of 599 exhibited the best performance with a porosity of 56.1 %, an average pore size of 305 nm, an electrolyte uptake of 339 %, a tensile strength of 38.3 MPa, and an ionic conductivity of 1.88 mS·cm−1. The lithium-ion battery prepared with the optimal RC separator had a specific capacity of 156.55 mAh/g for 100 cycles at a current density of 0.5 C and a coulombic efficiency of more than 96 %, which was a clear advantage over the commercially available Celgard2400 and cellulose separators. This work makes contributions to the development of high-performance LIBs separators from cellulose.

Preparation of Antioxidant and Antifouling Ultrafiltration Membrane by Co-blending Eugenol with Polyethylene Glycol-Modified Polyvinylidene Fluoride

Polyvinylidene fluoride-graft-polyethylene glycol methyl acrylate (PVDF-g-PEGMA) was prepared by grafting PEGMA onto PVDF using a homogeneous irradiation grafting method. After incorporating various concentrations of eugenol, a natural antioxidant component of clove oil, the membranes were fabricated through non-solvent induced phase separation. The results indicated that the addition of eugenol did not alter the inherent properties of the membrane but slightly reduced the pore size and water flux. The cyclic flux test showed that eugenol did not compromise the anti-fouling performance of the membrane, with the flux recovery ratio exceeding 93%. The antioxidant performance test revealed that eugenol enhanced the membrane’s capacity to remove free radicals and imparted oxidation resistance in NaClO solution, making the modified membrane suitable for use in oxidizing environments. This study successfully demonstrated a simple method to prepare a bifunctional membrane with anti-fouling and antioxidant properties, potentially extending its service life and applicability in oxidative contexts.

Improved Protein Removal Performance of PES Hollow-Fiber Ultrafiltration Membrane with Sponge-like Structure.

The research used polyethersulfone (PES) as a membrane material, polyvinylpyrrolidone (PVP) k30 and polyethylene glycol 400 (PEG 400) as water-soluble additives, and dimethylacetamide (DMAc) as a solvent to prepare hollow-fiber ultrafiltration membranes through a nonsolvent-induced phase separation (NIPS) process. The hydrophilic nature of PVP-k30 and PEG caused them to accumulate on the membrane surface during phase separation. The morphology, chemical composition, surface charge, and pore size of the PES membranes were evaluated by SEM, FTIR, zeta potential, and dextran filtration experiments. The paper also investigated how different spinning solution compositions affected membrane morphology and performance. The separation efficiency of membranes with four different morphologies was tested in single-protein and double-protein mixed solutions. The protein separation effectiveness of the membrane was studied through molecular weight cutoff, zeta potential, and static protein adsorption tests. In addition, the operating pressure and pH value were adjusted to improve ultrafiltration process conditions. The PES membrane with an intact sponge-like structure showed the highest separation factor of 11, making it a prime candidate membrane for the separation of bovine serum albumin (BSA) and lysozyme (LYS). The membrane had a minimal static protein adsorption capacity of 48 mg/cm2 and had excellent anti-fouling properties. When pH = 4, the BSA retention rate was 93% and the LYS retention rate was 23%. Furthermore, it exhibited excellent stability over a pH range of 1-13, confirming its suitability for protein separation applications.

A microfluid-on-microfluid phase separation strategy fabricates high-throughout porous polyimide separator for lithium-ion batteries

The microstructures and thermal stability of separators are critical for the safety and performance of lithium-ion batteries; however, it is still challenging to fabricate advanced separators simultaneously achieving uniform and high-throughput interconnected microporous structures with high thermal stability. Here, based on a soluble polyimide (PI) with high thermal stability, we report a microfluid-on-microfluid phase separation strategy (MF2-PS) to address the above challenge. Compared to the traditional non-solvent induced phase separation by immersion, the MF2-PS strategy can achieve more controlled porous structures with sponge-like open channels at submicron scale. The high surface polarity of the PI-separator also exhibited good wettability with liquid electrolytes, and a high electrolyte uptake (182 wt%) for achieving a high ion-conductivity. It also showed much superior thermal stability as compared to PP separator. Finally, due to the unique porous structures, the PI-separator by MF2-PS strategy successfully delivered a discharge capacity of 161.9 mA h g−1 for LiFePO4 electrode, and very stable cycling performance. All these results indicates that the PI-separator by MF2-PS may find significant applications in safe and high-performance batteries.

Ternary Phase-Field Simulation of Poly(vinylidene fluoride) Microporous Membrane Structures Prepared by Nonsolvent-Induced Phase Separation with Different Additives and Solvent Treatments.

In this study, an existing ternary membrane system based on nonsolvent-induced phase separation (NIPS) with a phase-field model was optimized. To study and analyze the effects of different additives on the formation of the skin layer and the effects of the three solvents on membrane characterization under the same conditions, two-dimensional simulations of the relevant parameters of a poly(vinylidene fluoride) (PVDF) membrane system were performed. The specific application of quaternary substances in ternary membrane systems was elaborated by determining the cohesive energy density between the additives and solvents, followed by the interaction parameters χ under the joint effect of the two. The results showed that the PVDF microporous membrane formed a dense surface layer at the mass transfer exchange interface, and with an increase in the poly(ethylene glycol) (PEG) concentration, the phase separation of the skin layer was predominantly transformed from liquid-solid partitioning to liquid-liquid partitioning; the number of membrane pores increased with increasing poly(vinylpyrrolidone) (PVP) concentration. The N,N-dimethylacetamide (DMAc) solvent system had the most stable thermodynamic properties; the dimethyl sulfoxide (DMSO) solvent system had mostly large pores running through the membrane and exhibited a porous structure. Related experiments also validated the model. Therefore, this model can be applied to other PVDF ternary membrane systems to better understand the structural development of microporous PVDF membranes under different conditions.

Structurally stable copolymer ultrafiltration membranes prepared via vinyl chloride suspension copolymerization and tannic acid in-situ modification integration

Polyvinyl chloride ultrafiltration membranes, widely used in various industries, are hindered by their high susceptibility to contamination. To address this concern, researchers have investigated diverse modification methods, encompassing surface modification and physical blending. Although surface modification provides stability, but it is intricate, expensive, and may result in pore clogging. Physical blending is a simpler approach but lacks durability and stability. Tannic acid (TA), a natural compound, has attracted attention for its potential in membrane modification due to its diverse benefits. However, the existing methods, such as TA-metal networks, encounter challenges of weakened stability and reduced permeability of membrane. To solve these issues, this research presents a novel approach that integrates suspension copolymerization, polyaddition, and a sol–gel process to fabricate structurally stable copolymer ultrafiltration membranes. Active sites for sol–gel reactions were embedded into the copolymer through copolymerization. Subsequently, TA was added to the copolymer casting solution, and isocyanate propyltriethoxysilane was decorated onto TA through a polyaddition reaction. Following this, a non-solvent induced phase separation method was used for membrane fabrication. During the formation of the membrane, a sol–gel reaction occurred between the copolymer and the modified TA, ensuring both stable chemical cross-linking. The membrane demonstrates excellent permeability, fouling resistance, and long-term operational stability. This innovative approach not only addresses compatibility and leakage issues associated with traditional methods but also ensures the stable integration of hydrophilic functional monomers within the copolymer matrix. The proposed method holds promise for advancing applications of ultrafiltration membrane technology in various complex environments.

Effect of layered transition metal dichalcogenide hybrid nanomaterials on the piezoelectric performance of non‐solvent induced phase separated polyvinylidene fluoride

AbstractLayered transition metal dichalcogenides (TMDs) with high aspect ratios enhance the alignment of polymer chains and induce a preferred orientation of the polymeric crystallites when incorporated into polyvinylidene fluoride (PVDF). In addition to offering an effective charge‐transfer mechanism, TMDs give PVDF more rigidity and piezoelectric qualities. This work reports the non‐solvent induced phase separation (NIPS) introduced while developing the PVDF/MoS2 composites. During the NIPS, the PVDF chains become phase‐separated, which induces high polarization in the PVDF matrix. Phase‐separated PVDF/MoS2 composites show high porosity and charge distribution attributed to the enhanced piezoelectric output voltage. While the neat PVDF demonstrated very feeble output voltage generation, the hybrid composite containing 2 wt.% of MoS2/ZnO facilitated almost 20 times higher performance (peak‐to‐peak voltage of 2.4 V). This work yielded a phase‐separated composite that finds uses in energy harvesting, sensors, and actuators, among other fields.Highlights NIPS creates high‐porosity composites with improved charge distribution. Layered TMDs improve charge‐transfer mechanism and PVDF's electrical properties. 2 wt.% MoS2/ZnO exhibits nearly 20 times higher voltage generation than neat PVDF.

Facile Lithium Densification Kinetics by Hyperporous/Hybrid Conductor for High-Energy-Density Lithium Metal Batteries.

Lithium metal anode (LMA) emerges as a promising candidate for lithium (Li)-based battery chemistries with high-energy-density. However, inhomogeneous charge distribution from the unbalanced ion/electron transport causes dendritic Li deposition, leading to "dead Li" and parasitic reactions, particularly at high Li utilization ratios (low negative/positive ratios in full cells). Herein, an innovative LMA structural model deploying a hyperporous/hybrid conductive architecture is proposed on single-walled carbon nanotube film (HCA/C), fabricated through a nonsolvent induced phase separation process. This design integrates ionic polymers with conductive carbon, offering a substantial improvement over traditional metal current collectors by reducing the weight of LMA and enabling high-energy-density batteries. The HCA/C promotes uniform lithium deposition even under rapid charging (up to 5mA cm-2) owing to its efficient mixed ion/electron conduction pathways. Thus, the HCA/C demonstrates stable cycling for 200 cycles with a low negative/positive ratio of 1.0 when paired with a LiNi0.8Co0.1Mn0.1O2 cathode (areal capacity of 5.0mAhcm-2). Furthermore, a stacked pouch-type full cell using HCA/C realizes a high energy density of 344Whkg-1 cell/951WhL-1 cell based on the total mass of the cell, exceeding previously reported pouch-type full cells. This work paves the way for LMA development in high-energy-density Li metal batteries.

Study on design strategies and on new structure-performance relationships for CO2 capture in gas-liquid hollow fiber membrane contactors

The urgent need for carbon dioxide (CO2) capture technologies motivates this chemical engineering study, which systematically investigates the influence of macroscopic and microscopic structure on the CO2 absorption performance of hydrophobic alumina (Al2O3) hollow fiber membrane (A-HFMs) contactors. Six different A-HFMs prepared using the non-solvent-induced phase separation (NIPS) method with select solvents followed by sintering at 1300°C were then tested for chemical CO2 absorption in an A-HFM contactor using a monoethanolamine (MEA) solution. The hydrophobicity of the coatings applied on the A-HFM surfaces was confirmed by the water contact angle and thermogravimetric (TGA) analysis. Pearson's statistical analysis of a correlation matrix revealed the strength of relationships between nine variables, including outer diameter (mm), inner diameter (mm), percentage of sponge layer (%), pore size (nm), maximum pore size (nm), mechanical strength (MPa), surface porosity (m−1), overall porosity (%), and CO2 absorption flux (mol m−2 s−1). Building upon these findings, this study unveils a novel non-linear function linking three specific microscopic characteristics— pore size, surface porosity, and a geometric sponge layer factor—to CO2 absorption flux, offering valuable insights for optimizing hydrophobic A-HFM design and enhancing CO2 capture efficiency. The A-HFM, characterized by the combination of three factors (higher pore size, increased surface porosity, and a thicker sponge layer), achieved a CO2 absorption flux of 6.36 ×10−3 mol m−2 s−1 at room temperature, showcasing its exceptional performance in capturing CO2. The resulting empirical morphological factor provides a novel approach for enhancing the performance of CO2 absorption through A-HFM design optimization.

“Flexible-strong” polylactic acid porous membrane via tailored polymerization degree of lactic acid side-chains grafting for passive daytime radiative cooler

Aerogel possesses the advantages of high specific surface area, low density, and high porosity, which have shown great application in thermal regulation due to its efficient light scattering capability. However, traditional polymer-based aerogels have poor mechanical properties and lack ductility in outdoor applications, the cooling efficiency of the material is easily affected by damage during transportation, installation, and environmental factors. In this work, combining the porous nature of aerogels and the high ductility of membranes, a polylactic acid-based porous membrane cooler was developed by combining a regular honeycomb surface porous structure design and physical/chemical modification to enhance flexibility, using a simple non-solvent induced phase separation method. This porous membrane exhibits both super-flexibility (116 % elongation at break) and porous characteristics. It achieves a sub-ambient temperature decrease of 4–6 °C under direct sunlight. The optimized porous membrane demonstrates high solar reflectance (94 % of peak reflectivity, 90 % of average reflectivity) and strong infrared emissivity (96 % of peak emissivity, 91 % of average emissivity), it also maintains a solar peak reflectivity of 91 % under 100 % tensile strain and 1000 bending cycles, the cooler still maintains a cooling effect of 2–5 °C below ambient temperature. This work paves the way for developing mechanical flexible and strong radiative coolers for thermal regulation.

A Flexible Capacitive Pressure Sensor Based on Thermoplastic Polyurethane Porous Films by Non-Solvent Induced Phase Separation

A Flexible Capacitive Pressure Sensor Based on Thermoplastic Polyurethane Porous Films by Non-Solvent Induced Phase Separation

Environmentally Friendly Photothermal Membranes for Halite Recovery from Reverse Osmosis Brine via Solar-Driven Membrane Crystallization.

Modern society and industrial development rely heavily on the availability of freshwater and minerals. Seawater reverse osmosis (SWRO) has been widely adopted for freshwater supply, although many questions have arisen about its environmental sustainability owing to the disposal of hypersaline rejected solutions (brine). This scenario has accelerated significant developments towards the hybridization of SWRO with membrane distillation-crystallization (MD-MCr), which can extract water and minerals from spent brine. Nevertheless, the substantial specific energy consumption associated with MD-MCr remains a significant limitation. In this work, energy harvesting was secured from renewables by hotspots embodied in the membranes, implementing the revolutionary approach of brine mining via photothermal membrane crystallization (PhMCr). This method employs self-heating nanostructured interfaces under solar radiation to enhance water evaporation, creating a carefully controlled supersaturated environment responsible for the extraction of minerals. Photothermal mixed matrix photothermal membranes (MMMs) were developed by incorporating graphene oxide (GO) or carbon black (CB) into polyvinylidene fluoride (PVDF) solubilized in an eco-friendly solvent (i.e., triethyl phosphate (TEP)). MMMs were prepared using non-solvent-induced phase separation (NIPS). The effect of GO or GB on the morphology of MMMs and the photothermal behavior was examined. Light-to-heat conversion was used in PhMCr experiments to facilitate the evaporation of water from the SWRO brine to supersaturation, leading to sodium chloride (NaCl) nucleation and crystallization. Overall, the results indicate exciting perspectives of PhMCr in brine valorization for a sustainable desalination industry.

Effective solar-driven evaporators with urchin-like CuO particles and directional polyvinylidene fluoride scaffolds via directional dimethyl sulfoxide crystallization and non-solvent induced phase separation

Solar-driven evaporators with vertical channels usually exhibit excellent desalination due to the fast water transportation and excellent salt tolerance, which are often fabricated via a directional liquid nitrogen-assisted ice templating method and freeze-drying process. However, they are reliant on a very limited number of water-soluble polymers and hydrophilic inorganic materials, and the freeze-drying process costs a long time and much energy. A highly efficient and straightforward process for the fabrication of solar-driven evaporators with directional channels from water-insoluble materials is urgent. Here, water-insoluble polyvinylidene fluoride was dissolved in dimethyl sulfoxide (DMSO), and then the solution was engineered to PVDF scaffolds by the combination of directional DMSO crystallization with the commonly porous membrane formation method of non-solvent (water) induced phase separation. The result is the creation of oriented perpendicular pores to the surfaces and framberry-like microparticles on the pore walls. After the in situ deposition of urchin-like CuO particles with high solar adsorption on PVDF scaffolds, PVDF/CuO solar-driven evaporators have been successfully constructed. The evaporate rate depends on the PVDF content and CuO loading. Briefly, PVDF/CuO evaporators fabricated from high PVDF content of more than 3 wt% have low porosity, slow water supply, and poor hydrophilicity, resulting in a low evaporate rate and high evaporation enthalpy. The optimized 3D PVDF/CuO evaporator (V3-9 h) with a PVDF content of 3 wt% and CuO loading of 31.3 ± 1.6 wt% has a high pure water evaporation rate of 3.2 ± 0.2 and 3.5 ± 0.3 kg m-2h−1 under sun illumination at 1 and 2 kW m−2, respectively. And the evaporation enthalpy is as low as 1083.8 ± 25.5 J/g, 55 % lower than pure water. Moreover, the sample exhibits a similar evaporation rate in 3.5 wt% NaCl solution because the verticle channels endow the evaporator with excellent salt tolerance. The facile and scalable fabrication process of solar-driven evaporators with directional channels will greatly boost the development of cost-effective desalination.

Efficient Dye Extraction from Wastewater Using Indium-MOF-Immobilized Polyvinylidene Fluoride Membranes with Selective Filtration for Enhanced Remediation.

Industrial activities have led to releasing harmful substances into the environment, necessitating the elimination of these toxic compounds from wastewater. Organic dyes, commonly found in industrial effluents, pose a threat to ecosystems and human health. Conventional treatment methods often suffer from limitations such as high cost and poor efficiency. Metal-organic frameworks (MOFs) have emerged as promising materials for selective separation, including membrane filtration (MF). Mixed-matrix membranes (MMMs) combining MOFs with polymers offer improved filtration properties. In this study, MMMs were fabricated by incorporating synthesized In-MOF with a polyvinylidene fluoride (PVDF) polymer (In-MOF@PVDF MMMs) using the nonsolvent-induced phase separation process. The MMMs were evaluated for the MF of various organic dyes, achieving notable removal efficiencies. The membrane containing 20% In-MOF (M4) demonstrated exceptional performance, removing 99% of the methylene blue (MB) dye. Additionally, membrane M4 effectively filtered Azure A (AZA), Azure B (AZB), and toluidine blue O (TOLO) with a removal efficiency of 99%. However, for Rhodamine B (RHB) and methyl orange (MO), the removal efficiencies were slightly lower at 74 and 39%, respectively. Further, these membranes are utilized in selective dye filtration in the MB+/RHB+ and MB+/MO- systems, where the selectivity was found for MB. The isothermal and DFT studies revealed the membrane's behavior with dye mixtures, while water stability and regeneration studies confirmed its durability. Thus, these findings highlight the potential of In-MOF@PVDF MMMs for effective and selective dye removal in wastewater treatment applications.

Fabrication of anti-fouling membranes of polyvinylidene fluoride (PVDF) with the addition of cellulose nanofibers (CNF)

In this study, cellulose nanofibers (CNF) were synthesized for the fabrication of polyvinylidene fluoride (PVDF) membranes using the non-solvent-induced phase separation (NIPS) technique with distilled water as the non-solvent. The hybrid membranes exhibited an asymmetric morphology, along with increased porosity and hydrophilicity with the rising concentration of CNFs. Thermal analysis revealed that all membranes are thermally stable up to approximately 430 °C, indicating their viability for high-temperature applications. Filtration tests demonstrated an enhanced permeate flux and albumin retention with the addition of CNF. The membrane with 1.5 wt% CNF increased solute retention by 19.67 % compared to the PVDF membrane. Furthermore, the hybrid membranes exhibited improved flow recovery rates and a reduction in irreversible fouling. These findings underscore the hydrophilic and anti-fouling properties of the membranes produced in this study, making them a promising solution to enhance the efficiency and sustainability of filtration and separation processes. Their significant potential for water treatment applications in the near future is highlighted.

Novel ethylenediamine-β-cyclodextrin grafted membranes for the chiral separation of mandelic acid and its derivatives.

In the present study, flat cellulose acetate ultrafiltration membranes were prepared first by nonsolvent induced phase separation method. Then chiral membranes for separating the enantiomers were prepared by grafting the ultrafiltration membranes using ethylenediamine-β-cyclodextrin as the chiral selector and epichlorohydrin as the spacer arm. The pure water permeability of the ultrafiltration membrane was around 115 L·m-2·h-1·bar-1. The properties of the chiral membranes were characterized using infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM). The chiral membrane performance in enantiomer separation was evaluated with racemates, such as mandelic acid (MA), 2-chloromandelic acid (2-ClMA), 4-chloromandelic acid (4-ClMA), and methyl mandelate (MM). The influence of feed concentration on the separation efficiency was also investigated. The results indicated that the enantiomeric excess percentages (e.e%) of the racemic mixtures for these four chiral compounds were up to 31.8%, 25.4%, 17.8%, and 32.6%, respectively. The binding free energy of the chiral selector with the (S)-enantiomer calculated by molecular dynamics simulations was stronger than that with the (R)-enantiomer, which was consistent with the experimental results (higher concentration of (R)-enantiomer in the permeate). This supports the affinity absorption-separation mechanism.

Stability and kinetic insights for ibuprofen removal from aquaculture wastewater using green supported ionic liquid membranes

Pharmaceutical residues in aquaculture effluent have become a growing environmental concern due to their potential ecological impacts. Supported ionic liquid membranes (SILM) offer a promising solution for extracting micropollutants from contaminated sources. SILM was developed using Aliquat 336 in sunflower oil (SFO) as a carrier solution, specifically targeting ibuprofen (IBP) in aquaculture wastewater. Different solid supports are fabricated through the nonsolvent-induced phase separation (NIPS) process and characterized by SEM, EDX, contact angle, FTIR and porosimeter. PVDF support is selected as solid support for immobilization of the carrier solution owing to its properties of having an asymmetrical shape, thickness of 48.8 µm, porosity of 72% and contact angle of 89.0° (feed side) and 85.3° (stripping side). The percentage of carrier loss obtained was only 1.10%. The optimal conditions for IBP removal were obtained at 0.50 M Aliquat 336, with a feed phase pH of 5.5 and stripping phase pH of 8. Further tests on real aquaculture wastewater affirmed the system’s efficacy in removing IBP and maintaining the stability at least the fifth cycle of membrane reusability. This study underscores the viability of proposed SILM system in mitigating IBP from aquaculture sector.

Polyacrylonitrile‐based porous polymer spheres and their conversion to N‐doped carbon materials for adsorption and electrocatalysis

AbstractBecause of their tunable porosity and specific surface area, porous materials are of high interest for the purification of wastewater by adsorption as well as in electrocatalysis, where, in particular, developing metal‐free carbon‐based catalysts for the oxygen reduction reaction (ORR) is researched. The carbon spheres presented here can meet these two requirements simultaneously. Porous polyacrylonitrile (PAN) spheres were firstly prepared by droplet shaping cum nonsolvent induced phase separation. Then, they were converted to nitrogen‐doped carbon spheres by two‐step carbonization via preoxidation and pyrolysis. During the pyrolysis step, carbon dioxide was used to reopen the pores of the materials that had been blocked after the preoxidation step. By this way, specific surface area values of carbon spheres of more than 1000 m2/g could be obtained. Best performing carbon materials (C#3) showed high adsorption capacity (e.g., 296 mg/g for methyl orange at solute equilibrium concentration of 24 mg/L in water). The XPS analysis revealed that only quaternary (N‐Q) and pyridinic (N‐6) nitrogen sites were found in these carbon spheres. The best ORR performance was found also for C#3 carbon spheres, with a potential of 0.81 V versus reversible hydrogen electrode (RHE) at −1 mA/cm2 and electron transfer number of 3.5 at 0.6–0.8 V versus RHE, as determined by rotating disk or rotating ring disk electrode tests. In conclusion, all results confirm that these PAN‐derived carbon spheres are potentially valuable materials for both wastewater treatment by adsorption and electrocatalytic oxygen reduction.