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This current paper presented a new candidate and potentially to improve the current membrane materials in water filtration process. With that, the primary materials used in this research study is layered double hydroxides (LDH) nanoclay which can be obtained from earth minerals and self-synthesized from inorganic salts were discussed thoroughly to help a better understanding of these materials. However, the current technologies of water separation were still lagging behind and ineffective especially in removal of divalent metal ions and multivalent salts. Infeasibility of reverse osmosis membrane make it not a viable option for divalent salts filtration. With that, nanofiltration (NF) membrane offered as an alternative to substitute available method. In this study, thin film nanocomposite (TFN) membranes were fabricated by incorporating layered double hydroxides (LDH) nanoclay. The LDH nanoclay with different loading ratio of 0, 0.05, 0.1, 0.15 and 0.2 were impregnated into polyamide layer on top of polysulfone substrates. The fabricated TFN were characterized in terms of physicochemical properties (SEM and FTIR) and membrane hydrophilicity (contact angle). After the addition of LDH, the morphological structures of TFN membranes were changed and the surface hydrophilicity was enhanced significantly. FESEM images displayed a typical ridge and valley morphology with nodule-like structures. As the LDH loading was increased, the contact angle decreased from 34.56˚ to 15.76˚ showing the surface hydrophilicity of membrane is improved. The separation performance of membrane was evaluated in terms of salt rejection ability by cross flow filtration system. The best performance NF membrane was found to be TFN 0.05 with high water flux and MgCl2 rejection with values of 24.18 L/m2.h and 91% respectively. This study has experimentally validated the potential of LDH materials in membrane process for improvement in water separation process.

The potential use of deep eutectic solvents (DESs) for anhydrous conductivity of sulfonated polysulfone membrane is presented. To this end, different molar ratios of sodium bromide as hydrogen bond acceptor (HBA) and ethylene glycol as hydrogen bond donor (HBD) are used for the synthesis of DESs. Two sulfonation degrees (DS) of 30 and 40% are also adjusted for the synthesis of sulfonated polysulfones. The synthesized DESs have suitable thermal stability as well as low viscosity to provide interconnected ionic pathways within the membranes. The proton conductivity of membranes is mainly influenced by the HBD/HBA molar ratio of DES as well as the DS of sulfonated polymer. The maximum proton conductivity of 301 mS/cm at 100 °C is obtained for the polymer with 40% DS containing a DES with a higher HBD/HBA molar ratio. The prepared composite membranes have great potential for fuel cell performance, especially in anhydrous conditions.

The performance of the existing forward osmosis membranes is mainly restricted by the internal concentration polarization (ICP) of solutes inside the substrate. In the current work, the poly (methyl methacrylate) (PMMA) grafted ZnO nanoparticle (ZnO@PMMA) was synthesized and introduced as a novel nanofiller to minimize the ICP effect within the polysulfone (PSf) support layer. It was revealed that the ZnO@PMMA nanoparticles could improve the characteristics of the PSf membrane substrate, including the porosity, hydrophilicity, pure water permeability (PWP) and morphology. The optimal support layer has a porosity of 82.4% and PWP of 186.5. The FO performance of modified membranes in terms of water flux (Jw, LMH) and reverse salt flux (Js, gMH) were thoroughly evaluated using a cross-flow system. Also, the water permeability (A, LMH.bar−1) and salt rejection (R, %) were measured by a dead-end RO setup. The obtained TFN-ZP.2 membrane (modified with 0.25 wt% of ZnO@PMMA) showed significantly improved FO water flux (up to 14.6 LMH) and water permeability (2.3 LMH/bar) which was about 2 times that of the bare TFC-FO membrane (5.9 LMH and 1.2 LMH/bar). Additionally, the structure parameter (S) was significantly alleviated (693 ± 85 µm) after the ZnO@PMMA incorporating, indicating reducing the unwanted ICP in TFN-FO membranes.

Background Increasing the molecular weight and addition contents of pore forming agents have been acknowledged as effective ways to improve permeability in membranes fabricated via nonsolvent induced phase separation (NIPS). However, these techniques negatively impact the overall pore size and mechanical strength of the resulting membranes. Facilitating the mutual diffusion of water (coagulant) and dope solutions (MDWDS) during NIPS is the key to obtain porous membranes with high permeability. Methods Here, surfactants assisted nonsolvent induced phase separation (SA-NIPS) is proposed and used to regulate MDWDS during NIPS. Significant findings Surfactants facilitate MDWDS. More importantly, MDWDS can be advanced by elevating the hydrophilic interaction force of water and the hydrophilic heads of surfactants while keeping the hydrophobic interaction in the dope solutions constant. SA-NIPS improves the surface porosity of polysulfone (PSF) membranes, thus increasing the permeability of PSF membranes (up to 2.9 times). Moreover, the tensile strength and pore sizes of PSF membranes are maintained. This research may provide a feasible insight into regulation of the morphology and permeability of NIPS-prepared membranes without compromising their pore size and tensile strength.

Polysulfone (PES) membranes are among the rare membranes that are capable of double filtration: a pre-filter layer captures agglomerates and a thin-dense layer is responsible for the main separation process. This work aims to enhance the permeability and H2/N2 and CH4/N2 of the dense layer of PES by mixing it with low concentrations of carbon nanotubes (CNTs: 0.01–0.03 wt.%) using solution casting and doctor blade techniques. The pore topology, microstructure, chemical, thermal, and mechanical properties of the synthesized CNTs/PES membranes were investigated using FTIR, XRD, TGA, and a universal testing machine, while permeability of single CO2, H2, N2, and CH4 permeability of the CNTs/PES membranes were tested under different temperatures (20–60 °C) and pressures (1–6 bar). Also, the effect of added CNTs, separation temperature, and pressure on the gas separation mechanism were investigated. The results showed that adding of CNTs contributed to increase in porosity from 81.7% (PES) to 88.4% (CNTs/PES) and decrease in pore sizes from 84 nm (PES) to 50 nm (CNTS/PES). Meanwhile, the thermal and mechanical analysis showed that CNTs/PES membranes had higher thermal stability and somewhat lower strength compared with neat membranes. Also, the permeability measurements showed a big increase when only 0.01 wt.% of CNTs had been added, where H2, CH4, N2, CO2 permeabilities were increased up to 28,553, 11,358, 7540, 6720 Barrer, respectively, vs 10.4, 4.6, 13.7, and 12.3 Barrer in case of PES membranes. In addition, CO2/N2, CH4/N2, and H2/N2 selectivity of CNTs/PES membranes were enhanced by 29%, 396%, and 426%, respectively, as a result of pores refining and increasing of free space in the prepared CNTs/PES membranes. According to these results, CNTs/PES membranes with small loading of CNTs have a tremendous ability to deal with separation of H2/N2 and CH4/N2, what make them promising candidates for clean energy extraction applications.

Carbon nanotubes (CNTs) are promising for realizing ultrafast membranes with implications to molecular separations and beyond. However, it is a big challenge to harness the potential of CNTs for designing scalable yet high-performance membranes. Here we systematically explore the role of loading and vacuum-assisted alignment of CNTs for improving the desalination performance of polyamide (PA) based thin-film composites. To rule out the dispersion instability issues, we focused on carboxylated single-walled CNTs (SWCNTs) commercially available in the market. After applying a pre-treatment for cleaning, we deposited SWCNTs on porous polysulfone supports by vacuum filtration and coated a PA layer on top via interfacial polymerization. Morphological assessments supported by polarized Raman microspectroscopy allowed the quantification of SWCNT alignment. At an optimum SWCNT loading, which we found critical for alignment, the water permeability of resulting membranes significantly improved without compromising NaCl selectivity. Also, we achieved an improved boric acid selectivity, arguably owing to the hydrophobic nature of nanotube channels. Moreover, nanotubes promoted resistance against chlorine degradation and improved mechanical strength. Vacuum deposition is instrumental for infiltrating SWCNTs into the support layer, but a mat layer forms between the support and PA layers when SWCNT loading exceeds the limit that the support pores can accommodate. Given that we use ordinary SWCNTs and a scalable methodology (vacuum-assisted infiltration), the developed membranes are promising for practical applications. © 2021 Elsevier Ltd

Photocatalytic materials can be used as self-cleaning functional materials to alleviate the irreversible fouling of ultrafiltration membranes. In this work, the small size g-C3N4/Bi2MoO6 (SCB) blended polysulfone (PSF) ultrafiltration membranes was fabricated by hydrothermal and phase inversion methods. As a functional filler of ultrafiltration membranes, the small size g-C3N4 nanosheet decorated on the surface of Bi2MoO6 can enhance the photocatalytic performance for bovine serum albumin (BSA) degradation, and remove irreversible fouling under visible light irradiation. In addition, the introduction of SCB microspheres into PSF matrix obviously increased the porosity of ultrafiltration membranes. Therefore, the SCB-PSF ultrafiltration membranes displayed excellent antifouling performance (flux recovery ratio is 82.53%) and BSA rejection rates (94.77%). SCB-PSF also had high photocatalytic self-cleaning activity, indicating excellent application prospects in organic wastewater treatment.

In this study, cellulose nanofibrils (CNF) of high charge (H-P-CNF) and screened size (H-P-CNF-S) were fabricated by increasing the charge of phosphorylated cellulose nanofibrils (P-CNFs) during the pre-treatment step of CNF production. Results show that the H-P-CNF have a significantly higher charge (3.41 mmol g-1) compared with P-CNF (1.86 mmol g-1). Centrifugation of H-P-CNF gave a supernatant with higher charge (5.4 mmol g-1) and a reduced size (H-P-CNF-S). These tailored nanocelluloses were added to polyvinyl alcohol (PVA) solutions and the suspensions were successfully coated on porous polysulfone (PSf) supports to produce thin-film nanocomposite membranes. The humid mixed gas permeation tests show that CO2 permeability increases for membranes with the addition of H-P-CNF-S by 52% and 160%, compared with the P-CNF/PVA membrane and neat PVA membrane, respectively.

Metal–organic frameworks (MOFs) exhibit high proton conductivity, thermal stability, and offer immense flexibility in terms of tailoring their size. Owing to their unique characteristics, they are desirable candidates for proton conductors. Nevertheless, constructing ordered MOF proton channels in proton exchange membranes (PEMs) remains a formidable challenge. Herein, blend nanofibers of cellulose and UiO-66-NH2 (Cell–UiO-66-NH2) obtained via the electrospinning process were embedded in a sulfonated polysulfone matrix to obtain high-performance composite PEMs with an orderly arrangement of UiO-66-NH2. Comprehensive characterization and membrane performance tests reveal that composite membrane with 5 wt% (nominal) UiO-66-NH2 have revealed high proton conductivity of 0.196 S cm−1 at 80 °C and 100% relative humidity. Meantime, the composite membrane exhibits a low methanol permeability coefficient (~5.5 × 10−7 cm2 s−1). Moreover, the composite membrane exhibits a low swelling ratio (17.3%) even at 80 °C. The Cell–UiO-66-NH2 nanofibers exhibit strong potential for use as a proton-conducting nanofiller in fuel-cell PEMs.

This study aimed to design a facile and efficient protocol for upgrading the performance indices of polysulfone (PS) membrane (porosity, hydrophilicity, pure water flux (PWF), surface charge, and fouling-resistance) by blending with newly synthesized poly(ionic) crosslinked chitosan Schiff bases (PICCSBs). The PS-PICCSBs mixed-matrix membranes (MMMs) have successfully fabricated and characterized based on spectral and microscopic analyses, porosity, zeta potential, water contact angle, and water uptake (wettability) measurements. The PWF, fouling-resistance against bovine serum albumin (BSA), as well as ion exchange capacity (IEC) against nitrate anion were studied. The wettability, hydrophilicity and overall porosity of new MMMs have greatly increased, in comparison to a pristine PS membrane (M0). In addition, blending of PS with PICCSBs resulted in switching its surface from negatively- to positively-charged. The PWF of MMMs has increased to reach a maximum value of 238.6 L/m2 h for MMM1 (9.3-fold higher than M0). Meanwhile, BSA rejection has declined from 96.62% for M0 to 41.9% for MMM1. The fouling parameters results of MMMs indicated their low fouling propensity. The IEC of nitrate anions revealed that the nitrate uptake by MMM1 is higher than that for M0 and MMM2 by 34% and 14%, respectively.

Polysulfone is among the polymers known for excellent electrical resistivity, elongation capacity, transparency and thermal resistance. Polysulfone is being used in battery caps, oil pumps, oil control pistons, transmission parts, water treatment, etc. The focus of the presented work is to control the porosity level of polysulfone membranes through plasma treatment for water treatment application. Polysulfone membrane was fabricated using phase inversion method and treated with microwave plasma of oxygen under fixed plasma conditions. The membrane samples were plasma treated for 15 s to 30 s and analyzed for surface morphology, pore size distribution and functional groups. Presence of benzene rings, sulfonic groups and phenols groups in the samples were observed in a range of 855–1000 cm−1, 1290–1360 cm−1 and 3250–3420 cm−1, respectively. The blank sample had wider pore size distribution (3–18 µm) while plasma treated samples exhibited narrow pore size distribution. The pore size distribution after 15 s and 30 s of treatment ranged from 3 to 9 µm and 3 to 5 µm, respectively. Conclusively, uniform pore size distribution was possible after 30 s of plasma treatment.

The study conducted on polysulfone/iron oxide/alginate (PSF/IONPs/ALG) hollow fiber (HF) membranes were spun at various air gap distances (10, 30, 50 and 70 cm) for membrane morphology and anti-fouling properties in hemodialysis application. PSF/IONPs/ALG membranes were fabricated using dry-wet spinning process. Hollow fiber properties were investigated using scanning electron microscopy (SEM), contact angles, and ultrafiltration measurements. SEM results show that the cross-sectional morphology of the membranes was varies significantly over various air gap distances. The structure of the outer surface became more porous as the pore size and air gap distance increased. In addition, the hydrophilicity of the membrane increased by decreasing water contact angle from 78.56ο to 48.83ο at air gap distance of 10 to 50 cm. Moreover, the pure water permeability (PWP) was improved when air gap was increased up to 50 cm before showing a decreasing pattern. Similar trends were recorded in BSA rejection and antifouling test with the highest BSA rejection and Flux recovery ratio (FRR), 96.53% and 86.37%, respectively at 50 cm air gap.

High hydroxide conductivity and good stability of anion exchange membranes (AEMs) is the guarantee that anion exchange membrane fuel cells (AEMFCs) yield high power output for a long time. Balanced conductivity and stability can be better guaranteed by adopting a relatively low ion exchange capacity (IEC) while reducing the ion transport resistance Herein, a novel block copolymer AEM was designed and synthesized, which contains hydrophobic polymer of intrinsic microporosity (PIM) blocks and hydrophilic, quaternized polysulfone (PSF) blocks. The PIM block imparts high free volume to the membrane so that the resistance of hydroxide ion transport can be reduced; meanwhile, the hydrophilic block can self-assemble more easily to produce a better developed hydrophilic microphase, which may function as efficient channels for hydroxide ion transport. Both transmission electron microscopy images and small-angle X-ray scattering patterns suggested that the resulting AEM possessed a microphase separated morphology. The membrane showed a conductivity of 52.6 mS cm-l at 80 °C with a relatively low IEC of 0.91 mmol g−1. It also exhibited a good dimensional stability, swelling ratio maintained almost constant (ca. 17%) at 25 to 80 °C. The assembled H2/O2 fuel cell yielded a peak power density of 270 mW cm−2 at 560 mA cm−2. Our work demonstrates that incorporation of PIM in an AEM by means of block polymerization is an efficient way of promoting microphase separation and facilitating ion transport.

Polysulfone (PSF) is extensively used for the production of ultrafiltration (UF) membranes thanks to its high strength, chemical stability, and good processibility. However, PSF is intrinsically hydrophobic, and hydrophilic modification is always required to PSF-based membranes if they are intended to be used in aqueous systems. Facile strategies to prepare hydrophilic PSF membranes are thus highly demanded. Herein we spray coat a PSF-based amphiphilic block polymer onto macroporous substrates followed by selective swelling to prepare flat-sheet PSF UF membranes. The polymer is a triblock polymer containing PSF as the majority middle block tethered with shorter block of polyethylene glycol (PEG) on both ends, that is, PEG-b-PSF-b-PEG. We use the technique of spray coating to homogeneously dispense diluted triblock polymer solutions on the top of macroporous supports, instantly resulting in uniform, defect-free polymer coating layers with the thickness down to ~ 1.2 μm. The bi-layered composite structures are then immerged in ethanol/acetone mixture to generate mesoscale pores in the coating layers following the mechanism of selective swelling-induced pore generation, thus producing composite membranes with the mesoporous triblock polymer coating as the selective layers. This facile strategy is free from additional hydrophilic modification and much smaller dosages of polymers are used compared to conventional casting methods. The pore sizes, porosities, hydrophilicity, and consequently the separation properties of the membranes can be flexibly tuned by changing the swelling duration and the composition of the swelling bath. This strategy combining spray coating and selective swelling is upscalable for the production of high-performance PSF UF membranes.

Metal organic frameworks (MOFs) with marvelous properties have aroused enormous attention for different application especially gas adsorption and separation. In this regard, fabrication of MOF hybrids with carbon based materials is new strategy to upgrade MOF performance. In this study CuBTC (Copper benzene-1,3,5-tricarboxylic acid)/graphene oxide (GO) composite was synthesized and characterized by BET, SEM, TGA, XRD and FT-IR techniques. Then CuBTC and CuBTC/GO composite were incorporated into polysulfone (PSF) polymer to construct mixed matrix membranes (MMMs). The obtained membranes were characterized by SEM, TGA, XRD and tensile tests and their gas permeability was measured. The results were compared to those of CuBTC/PSF MMMs. It was revealed that CuBTC/GO composite as filler showed superior performance relative to CuBTC. For instance, 15 wt% loading of CuBTC/GO in PSF represented outstanding gas separation behavior while the same loading of CuBTC in PSF deteriorated performance of MMM. Well particle dispersion and favorable polymer-filler interaction were responsible for such observed difference. A high H2/CH4 and H2/N2 selectivity of 80.03 and 70.46 were recorded for CuBTC/GO in PSF (15 wt%) compared to 44.56 and 40.92 for CuBTC in PSF (15 wt%).

Global warming and environmental degradation have stimulated the drive towards the capture of large point source carbon emissions and reducing high energy intensity of industrial processes. Mixed membranes infused with high porosity silica sodalite are potential useful for pre-combustion CO2 capture. However, development of high quality mixed matrix membranes is a challenge. In this study, silica sodalite (SSOD) infused polysulfone (PSF) membranes were developed and evaluated for pre-combustion CO2 capture. The SSOD was obtained via topotactic conversion of layered silicates; and the membrane was prepared using the phase inversion method. The physicochemical nature of the SSOD and the SSOD/PSF was checked using XRD, SEM, and N2 physisorption at 77 K. Single gas permeation used to check membrane quality. N2 physisorption shows that the SSOD possesses higher surface area of 56.56 m2/g and pore volume of 0.181 cm3/g, when compared to that of the hydrothermally-synthesized hydroxy sodalite (HSOD) crystals (surface area: 27.43 m2/g; pore volume: 0.084 cm3/g). The SSOD/PSF membrane is asymmetric with higher mechanical strength than the ordinary PSF. Loading the PSF with SSOD enhanced its H2 permeance from 4.9 × 10−7 mol/m2·s·Pa but with a decrease in H2/CO2 separation factor from 2.2 to 0.6. While the enhanced H2 permeance is attributed to the enhanced porosity of the SSOD, the ideal selectivity is low but still within the values reported in literature. Increasing the SSOD loading up to 10 wt% enhanced the quality and performance of the PSF membrane, displaying H2 permeance of 6.5 × 10−7 mol/m2·s·Pa and a separation factor of 1.1. Though results reported in this study are promising, a robust synthesis protocol that will further enhance both the H2 selectivity and H2 permeance of the membrane is required. Furthermore, more studies are required on the process optimization and techno-economic feasibility for pre-combustion CO2 capture.

Adsorption- and membrane-based processes and materials for capture and separation of CO2 are gaining increased attention as alternatives to overcome current limitations of the traditional amine based absorption. In this study, hybrid nanostructures of metal organic frameworks (MOFs) and graphene oxide (GO) were synthesized, functionalized and used as adsorbents as well as fillers in mixed matrix membranes (MMMs). GO was fabricated by oxidation/exfoliation of graphite flakes and was subsequently functionalized with various amine-bearing agents. Two MOFs, ZIF-8 and UiO-66, and their composites with GO were also developed and further functionalized with amine groups as to enhance CO2 capacity and selectivity. In addition, MMMs synthesized using ZIF-8 and ZIF-8/GO composite fillers with polysulfone (PSF) as the polymeric phase were realized. The combined action of the MOF and GO counterparts towards enhancing CO2 separation performance was exemplified in both adsorbent and membrane modes.

The implementation of the pore-forming agent in the polymeric membrane has been applied for ages in enhancing the characteristics and performance of mixed matrix membrane. In this work, chlorophyll extracted from spinach has been used as an additional pore-forming agent alongside polyethylene glycol (PEG) to improve the polysulfone's pore structure (PSf) mixed matrix membrane. The effect of chlorophyll was investigated in terms of characteristics and performance of the mixed matrix membrane. As a result, the cross-section morphologies show that the pore structure was enhanced significantly inside the membrane structure for 0.25 wt% chlorophyll concentration, thus resulted in better hydrophilicity, surface roughness, and membrane porosity value. Plus, the permeation and rejection performance was increased drastically due to the pore formation inside the mixed matrix membrane structure. These results prove that the addition of chlorophyll with low concentration managed to improve the characteristics and performance of the fabricated mixed matrix membrane.

This work aims to investigate the polyamide (PA) morphology on polysulfone (PSf) membrane supports with different morphologies. It was achieved by systematically varying the N-Methyl-2-Pyrrolidone (NMP) and Dimethylformamide (DMF) solvent composition ratios in dope solution as adapted in Tiraferri et al. The PSf membrane support was firstly synthesized via phase separation technique. Next, the PA layer of the thin film composite (TFC) membrane was synthesized via consistent interfacial polymerization parameters on the PSf membrane support. The PA layer over the resulting array of membrane supports was investigated on their surface wettability, top and cross-sectional morphologies, and performances. Result shows that with more NMP content in the dope solution produces thin and dense sponge-like top skin layer with intense extended finger-like macrovoids sublayer. Meanwhile, more DMF content in the dope solution produces thicker and dense sponge-like morphology on the top skin with finger-like pores underneath. A layer of smaller and loosen ridge-and-valley PA structures is formed on the thicker and dense sponge-like morphology. TFC membrane over support made of NMP to DMF (40:60) was observed had the highest hydrophilicity with the lowest contact angle measurement of 61.9 ± 3.1°. It also performed the highest water permeability of 4.06 LMH/bar, moderate salt rejection of 95.65% with salt permeability of 1.9 gMH.

Proton conduction is a ubiquitous fundamental phenomenon in biological systems. Biology has solved the problem of energy-related proton conduction, in which the exposed amino acids in the protein ordered channels play a key role in proton conduction. In this contribution, amino acids (glutamate, lysine, and threonine) were attached to metal organic framework (MOF) nanoparticles, which were incorporated into sulfonated polysulfone matrix forming bio-proton channels for the nanocomposite membranes. It is shown in the results that the amino acid-functionalized MOF can help to enhance the proton conductivity and the proton exchange membrane with glutamate-functionalized MOF demonstrate excellent proton conductivity of 0.212 S cm−1 at 80 °C and 100% relative humidity. Meanwhile, the methanol permeability coefficient of the nanocomposite membrane is reduced to 5.8 × 10−7 cm2 s−1. The nanocomposite membranes demonstrate excellent proton conductivity, dimensional stabilities, water absorption, and resistance to methanol performance. Therefore, this material is promising for fuel cells.

In this study, the preparation procedures for the polysulfone (PSf) substrate and polyamide (PA) selective layers were systematically investigated to determine their effects on the separation performance of thin-film composite (TFC) forward osmosis (FO) membranes in terms of the permeate flux (Jw) and reverse solute flux (Js). Furthermore, the PA active layer was modified by adding different proportions of an emerging material, graphene oxide (GO), to increase Jw and decrease Js. The experimental results indicated that special attention should be paid to the preparation of the PSf casting solution, which required thorough degassing, sealing, and humidity and temperature control. The optimum casting height was discovered to be 175 μm. For PA layer formation, the same amount of polymer solutions (resulting thickness of 78.5 μm) on the top surface of the PSf substrate (on the side facing the water during phase inversion) resulted in the highest FO performance. GO modification of the PA layer at the dosage of 0.0175 wt% considerably enhanced Jw to 14 L m−2 h−1 and reduced Js to 0.23 mol m−2 h−1. However, higher GO dosage (0.02 wt%) led to lower membrane performance due to aggregation of GO nanoparticles, as confirmed using scanning electron microscopy. Next, the prepared membranes were applied to dye rejection and sludge concentration for water recovery. The virgin and modified FO membranes both exhibited high rejection efficiency (≥96.0 %) for dyes commonly used in the textile industry. The 0.0175 %-GO-modified FO membrane exhibited a higher concentration factor (1.67) and greater water recovery (40.0 %) than the virgin membrane (1.45 and 31.2 %, respectively). Therefore, the application of FO for water recovery is economic and environmentally friendly in terms of saving the transportation cost of sludge disposal while recovering water for reuse in wastewater treatment plants.

Novel imidazolium functionalized polysulfone (ImPS) membranes modified with zirconia (ZrO2) were synthesized through solution casting technique. Structural, morphological, thermal and mechanical analysis of the composite membranes confirmed adhesion and property enhancement caused by ZrO2. Water absorption investigations revealed better water absorption of the ImPS/ZrO2 membranes with intact morphology. Maximum ion exchange capacity and ionic conductivity for the composite membranes were obtained as 2.84 mmol/g and 80.2 mS/cm (50 °C) which was 21% and 47% higher as compared to pure ImPS membrane. Alkaline stability of the blend membranes was increased due to strong interaction between ZrO2 and ImPS molecules. Fuel cell performance using Pt/C catalysts exhibited OCP and power density elevation with incremental amounts of ZrO2 in the composite membrane composition. ImPS membrane with 10% ZrO2 recorded a highest OCP and power density of 1.04 V and 270 mW/cm2 which was 35% and 39% higher than the pure ImPS. Thus, the anion exchange membranes developed by ImPS/ZrO2 blending could be suiting well for alkaline fuel cells applications.

The effect of moisture absorption on the fiber-matrix interfacial shear strength (IFSS) between a polysulfone-modified epoxy matrix and silane surface-treated carbon fiber using a factorial experimental design was studied. Also, two conditions of relative humidity, 25%, and 95%, and likewise six combinations of interfacial adhesion level between the IM7 carbon fiber and the epoxy resin (diglycidyl ether of bisphenol A), modified with polysulfone (PSF) (8.75 wt.%), were studied. The results show that IFSS of the composites increased with both the carbon fiber surface treatments and the epoxy resin modification with PSF. Again, it was found the moisture content had a substantially detrimental effect on the IFSS. However, both the silane treatment and the (PSF) modification of the epoxy resin enhanced the composite's resistance to moisture attack. The ANOVA results showed that the three variables, matrix modification, fiber's surface treatment, and moisture content, were statistically significant. Furthermore, interactions fiber surface treatment–moisture content and fiber surface treatment–epoxy matrix were statistically significant and the interaction between fiber surface treatment and moisture content is as crucial as the polysulfone epoxy modification. It was also found that the silane-treated carbon fibers play a major role in preventing moisture attack to the composite.

Nanofiber-based ion-exchange membranes display distinctive features in energy applications. Bead formation and diameter of nanofibers determine the characteristics of these structures, which can be controlled by the electrospinning process. However, the electrospinning of polyelectrolytes is challenging due to the existence of ionic groups in the polymer structure. To this end, firstly, synthesis and characterization of hydroquinone-based sulfonated polysulfone with a 40% degree of sulfonation as a characteristic model are performed. To investigate the effect of electrospinning parameters on the morphology and diameter of the nanofiber, the appropriate numbers of experiments are designed using the Taguchi method; polymer solution concentration, voltage, feed rate, and needle to collector distance are considered as the design parameters. The proposed levels by the designed experiment are examined by scanning electron microscopy images. In the next step, the response surface method and the analysis of variance are employed to study the effect of each variable and the effectiveness of the final model. Finally, the parameters are optimized by the Genetic algorithm to gain the possible minimum diameter. Accordingly, the polymer solution concentration is the most effective parameter. Moreover, the electrospun thin bead-free nanofibers with an average diameter of about 97.5 nm are attained. The conductivity measurement (in water and temperature range of 20–100 °C) of the nanofibrous mat shows superior values of 0.1105–0.2851 S/cm compared to the dense membrane with a conductivity of 0.0791–0.2201 S/cm.

Dual modified ionic cross-link polysulfone (PSF) polymer-based proton-conducting membrane is synthesized with an aim to provide low methanol permeability without sacrificing the proton conductivity for direct methanol fuel cell application. The modification of pristine PSF membrane with aniline and further cross-linking by sulfuric acid was confirmed by its detailed characterization. The modified membrane achieved a high proton conductivity of 0.072 Scm−1 (30 °C) and 0.178 Scm−1 (110 °C) in low humidity condition (40%). The membrane exhibits low methanol permeability (2.5 × 10−8 cm2s−1) with high selectivity (28.4 × 105 Scm3s−1). The higher diffusivity of hydronium ion (H3O+) with an increase in hydration level and temperature was studied by molecular dynamics simulation and well agrees with experimental results in terms of proton conductivity. The reduced electrostatic interactions between the sulfonic acid group and H3O+ ion were confirmed by the radial distribution function analysis. These interaction pushes the H3O+ ion that helps in the transfer of proton by increases their coordination with water. Moreover, the high interaction of amine group with H3O+ ion also contributes to the proton conductivity enhancement. The dual modified membrane achived maximum power density of 0.19 Wcm−2 at 45 mA cm−2 and was 42% higher as compared to aniline treated polysulfone (APSF) membrane.

The present study focuses on the fabrication of polysulfone (PSf)-clay minerals impregnated hybrid membrane for treatment of Cu (II) ions. Blending and phase inversion methods have been employed to develop clay-based membranes by the mixing of bentonite, sepiolite and zeolite in the matrix of PSf. Moreover, characterization of fabricated membranes was carried out using SEM, FTIR, zeta potential, pore size and water contact angle measurement. Adsorption and filtration experiments were conducted to evaluate the permeation performance of the membrane. Obtained results of permeation study reveal that the presence of clay minerals in the matrix of modified membrane not only increases the adsorption and rejection efficiency for Cu (II) but, it also improves the flux of pure water. Among all developed membranes, the membrane prepared by the mixing of zeolite demonstrates the highest adsorption (2.82 mg/g) and rejection value (97%) towards Cu (II) at low pressure (0.5 bar). Regeneration performance results confirm the reusability of membrane up to 3–5 cycles along with 82.5–90% metal recovery. Based on significant metal recovery, clay-based low-cost zeolite/PSf membrane could be used to remove Cu (II) from water at low pressure to replace current conventional membrane.

A series of anion exchange membranes (AEM) based on poly (2, 6-dimethyl-1, 4-phenylene) (PPO) and polysulfone (PSF) blended with TiO2 were prepared and investigated. The water uptake, swelling ratio, ion exchange capacity, ion conductivity (IC) and thermal stability of the AEMs increased with increasing content of TiO2 within the composite membrane. The QPPO/PSF/TiO2 AEMs showed excellent thermal stability, high IC of 54.7 mS cm−1 at 80 °C, excellent alkaline stability and good performance when assembled in a methanol alkaline fuel cell. The highest peak power density of 118 mW cm−2 at a load current density of 300 mA cm−2 was observed for the QPPO/PSF/2%TiO2 composite membrane at 60 °C. The life time test of the fuel cell showed good membrane durability over a 60 h period. The results of this study suggest that the fabricated AEMs have good prospects for alkaline anion exchange membrane fuel cell applications.

In this study, the effects of 1-Ethyl-3-methylimidazolium tetrafluoroborate ionic liquid on CO2/CH4 separation performance of symmetric polysulfone membranes are investigated. Pure polysulfone membrane and ionic liquid-containing membranes are characterized. Field emission scanning electron microscopy (FE-SEM) is used to analyze surface morphology and thickness of the fabricated membranes. Energy dispersive spectroscopy (EDS) and elemental mapping, Fourier transform infrared (FTIR), thermal gravimetric (TGA), X-ray diffraction (XRD) and Tensile strength analyses are also conducted to characterize the prepared membranes. CO2/CH4 separation performance of the membranes are measured twice at 0.3 MPa and room temperature (25 °C). Permeability measurements confirm that increasing ionic liquid content in polymer-ionic liquid membranes leads to a growth in CO2 permeation and CO2/CH4 selectivity due to high affinity of the ionic liquid to carbon dioxide. CO2 permeation significantly increases from 4.3 Barrer (1 Barrer=10-10 cm3(STP)·cm·cm-2·s-1·cmHg-1, 1cmHg=1.333kPa) for the pure polymer membrane to 601.9 Barrer for the 30 wt% ionic liquid membrane. Also, selectivity of this membrane is improved from 8.2 to 25.8. mixed gas tests are implemented to investigate gases interaction. The results showed, the disruptive effect of CH4 molecules for CO2 permeation lead to selectivity decrement compare to pure gas test. The fabricated membranes with high ionic liquid content in this study are promising materials for industrial CO2/CH4 separation membranes.

Novel functionalized polysulfone with high local density of sulfonic acid groups, N,N-bis(sulfopropyl)aminyl-4-phenyl polysulfone or O,O′-bis(sulfopropyl)resorcinol-5-yl-4-phenyl polysulfone (PSF-X-C3H6SO3H, X = N or O) are synthesized. These polymers are synthesized by bromination of polysulfone followed by Suzuki cross-coupling reaction to graft the aminophenyl groups and the dimethoxyphenyl groups onto the polymeric backbone, followed by introduction of the sulfopropyl groups via sultone ring-opening reaction. In addition, the composite membrane of PSF-O-C3H6SO3H and PSF-N-C3H6SO3H is also synthesized for comparison. The maximum proton conductivity of composite PSF-O-C3H6SO3H and PSF-N-C3H6SO3H reaches 46.66 mS cm−1 at 95 °C and 90% RH, higher than PSF-O-C3H6SO3H (42.06 mS cm−1) and PSF-N-C3H6SO3H (38.76 mS cm−1). Meanwhile, the composite exhibits compromised water uptake and swelling ratio, and low methanol permeability. The excellent overall performance of the composite is attributed to phase-separation between the hydrophilic and the hydrophobic subphases, and the hydrogen-bonding network developed in the hydrophilic subphases.

Alkaline membrane (AM) shows fast transport of OH− towards the anode, separates both electrodes, and prevents fuel cross-over. To achieve good membrane conductivity and performance, high concentration of positively charged groups (quaternary ammonium) is an essential requirement, which also leads excessive swelling and mechanical instability of the AMs. Further, directly grafted quaternary ammonium (QA) with main polymer chain substitution and/or elimination reactions under strong alkaline environment. To avoid above-mentioned problems, we report preparation of cross-linked chloromethylated polysulfone based AM using (4,4,-((3,3′-bis(chloromethyl)-[1.1′-biphenyl]-4,4-diyl)bis(oxy))dianiline) (BCBD), a multi-functional novel cross-linking agent. Reported strategy compensates 2 mol of chloromethyl groups consumed during cross-linking, but additional functional groups (4 mol) with cross-linking agent. These AMs are designed to avoid the nucleophilic substitution (SN2) (grafting quaternary ammonium (QA) groups at benzylic position), and Hofmann elimination (E2) reactions (unavailability of β-H), under strong alkaline environment. Effective cross-linking has been confirmed by spectral analysis, and improves membrane stabilities and fuel cell performance. Single-cell alkaline membrane fuel cell (AEMFC) performance of most suitable (CR-QPS-03) membrane, showed comparatively high performance (open circuit voltage (OCV): 0.813 V, maximum power density: 103.6 mW/cm2 at 260.0 mA/cm2) in compare with Nafion 117 membrane (OCV: 0.682 V, maximum power density: 63.36 mW/cm2 at 220.0 mA/cm2) under similar experimental conditions.

Hybridization has become a powerful toolbox for developing ultrafiltration membranes with superior properties. However, it remains challenging to give full play to the utility of nanofillers because of poor bonding strength between polymers and inorganic nanomaterials. Herein, hydroxyapatite nanotubes (HANTs) were modified via bio-inspired polydopamine (PDA) and polyethylenimine (PEI) co-deposition. Meanwhile, polysulfone with carboxylation degree of 30% (PSF-COOH-30%) was synthesized by nucleophilic substitution reaction and employed as the membrane matrix. The results showed that when 0.3 wt% HANTs@PDA/PEI was incorporated, the pure water flux of the hybrid membrane achieved about 3.2 times that of the unfilled membrane and the rejection rate of bovine serum albumin (BSA) and humic acid (HA) remained 94.5% and 97.8%, respectively. Meanwhile, the flux recovery ratio for BSA and HA solutions (1 g/L) reached 90.8% and 93.7%, respectively. Specifically, the superiority of UF performance benefited from the synergistic effect of both the carboxylated polymer and the nanofiller. On one hand, the incorporation of HANTs@PDA/PEI promoted the formation of more porous membrane structure and improved the hydrophilicity of the membrane. On the other hand, due to the existence of COOH, the electrostatic repulsion between the membranes and contaminants enhanced the fouling resistance for BSA and HA. Conspicuously, the ease and versatility of co-deposition provide new ideas in the construction of nanohybrid and the favorable improvement renders that appropriate combination of polymer and additive is an effective way for developing future ultrafiltration membranes.

Choosing the property of the supporting membrane is crucial in preparing high performing nanofiltration membranes through interfacial polymerization. In this study, an oxygen rich membrane – cellulose triacetate (CTA) – was used to fabricate the support membrane. Polyamide was deposited onto the CTA support using interfacial polymerization of piperazine (PIP) and trimesoyl chloride (TMC). The concentration of the monomers was optimized. Furthermore, the polyamide layer prepared on CTA support exhibited higher separation efficiency for sodium sulfates and dyes compared to using traditional polysulfone (PSf) support. The oxygen groups of CTA facilitate better adsorption of amines on the surface; thus, using low concentration of PIP could still provide a defect-free polyamide layer. Utilizing the optimum condition, the polyamide/CTA membrane delivered a high pure water flux (operating at 6 bar) of 179.5 L/m2h with the following rejections: Na2SO4 = 98.4%; MgSO4 = 60.3%; MgCl2 = 15.0%; NaCl = 3.7%; Rose Bengal = 95.5%; Brilliant Blue R = 99.9%; Amido Black 10B = 90.6%; Orange G = 67.3%. Moreover, the polyamide/CTA membrane had excellent stability at a wide range operating conditions.

Designing polymer chains which contain building blocks with well-defined dimension is an efficient method to induce microphase separation and regulate the ionic channels of polymer electrolyte membranes (PEMs). In this study, a Wells-Dawson-type polyoxometalate (POM) is synthesized and chemically bonded to a norbornene derivative to prepare poly (POM) blocks. Then the block copolymer poly (POM)10-b-poly (COOH)300 is fabricated using poly (POM) and poly (COOH) blocks. Finally, the block copolymer is blended with sulfonated polysulfone (SPS). The electrostatic interactions between the block copolymer and SPS confer the blend membrane with enhanced mechanical and dimensional stabilities. Due to the homogenous distribution of POM clusters and the hydrophilic-hydrophobic interactions between POMs and polymer backbones, the adjacent hydrophilic domains are connected and continuous proton-transfer channels are induced. As a result, the blend membrane displays proton conductivity of 0.053 S cm−1 (25 °C, 100% RH) and 1.5 × 10−2 S cm−1 (80 °C, 40% RH), which are 2.52 and 6.25 times higher than those of the plain SPS membrane. Furthermore, SPS/POM-BC-30 shows a maximum power density of 164.9 mW cm−2, which is 54.7% higher than SPS.

This study concerns the synthesis and characterization of a new organic ultrafiltration membrane by phase inversion process based on the physical blends of Polysulfone/Polyetherimide (PS/PEI). The organic membranes we have synthesized are innovative; their first performance is to process soluble azoic dyes. They also have a low preparation cost and easy handling. We varied from 5 to 20 wt.% of PEI compared to the wt.% of PS. The microstructural membrane structure obtained was characterized by Fourier Transform Infrared spectroscopy (FTIR) and by nuclear magnetic resonance spectroscopy (NMR). The measurement of the contact angle characterized the surface properties of the membrane and the morphology was evaluated using the scanning electron microscope (SEM). The prepared membrane was evaluated by ultrafiltration of solutions of acid orange 74 (AO-74) and methyl orange (MO). The effect of adding polyetherimide in addition to the polysulfone increases the retention rate of the two dyes at a pressure of 4 bar. The results of the experimental filtration of the optimized membrane (prepared with 20 wt.% of PEI) have a water permeability of 22.66 L/hm2 bar, a maximum rejection rate of RM20 (AO-74) = 68.5% and RM20 (OM) = 64.7% respectively and a good high dye flow of around 10,08 L/h m2 for orange-74 acid AO-74 and 16,30 L/h m2 for methyl orange (OM).

Polysulfone ultrafiltration membrane was modified by novel nanoporous SBA-16-COOH during the membrane preparation via the phase inversion. The pure water flux and bovine serum albumin (BSA, as the foulant) flux were measured at 2 bar and the membranes’ antifouling behavior were analyzed. The membranes showed higher water flux after SBA-16-COOH addition up to 2 wt% and after that the flux slightly decreased which is attributed to the aggregation of SBA-16-COOH particles at the higher concentrations. SBA-16-COOH addition improved the surface hydrophilicity and led to elongated finger-like pores within the membranes cross section structure. The water flux after BSA flux was still higher than the one before BSA, thereby SBA-16-COOH addition resulted in better antifouling properties. In terms of BSA rejection, the nanocomposite SBA-16-COOH-based membranes outperform the pristine PSf membrane with rejection values up to 98.9%. The water contact angle confirmed the enhanced hydrophilicity of the membranes’ surface due to COOH functional groups of the nanomaterials which led to a higher permeability and an enhanced fouling resistance.

Two multi-amine, metformin (MTM) and polyethyleneimine (PEI), were used to prepare separative layer of composite membrane through chemical deposition with tea polyphenols (Tph), an inexpensive mixture of nature polyphenols, on a hybrid polysulfone (Psf) membrane. The supporting layer was a blend membrane of Psf, coupling agent treated sepiolite and cetyltrimethylammonium bromide (CTAB). Sepiolite and the surfactant improved surface hydrophilicity of membrane. Pure water flux (PWF) of membranes was increased from 33.97 to 611.46 L m−2 h−1 bar−1. The optimum mass ratio for MTM to Tph and PEI to Tph were 9.4:1 and 2.4:1 in chemical deposition reaction, respectively. MTM-Tph (MT) surface was negative charged while PEI-Tph (PT) was positive charged. Monomer reactivity determined the thickness of functional layer. Both composite membranes showed dyes rejection capacity at 1 bar. PT layer was thicker than MT, so did its rejection for dyes. The rejection of PT for 5 dyes were all higher than 98% and remained at 99.3% and 98.6% in 200 h for Congo red (CR) and neutral red (NR). PT membrane displayed the potential in textile waste water treatment.

Lithium metal has been considered to be the most promising anode material for the new generation of energy-storage system. However, challenges still stand in protecting lithium metal from spontaneous reactions with electrolytes and preventing the dendritic propagation, both of which would lead to undesirable decrease in Coulombic efficiency. Polysulfone (PSf) membrane with high rigidity and free-volume cavities of approximately 0.3 nm was employed to provide a stable interface on the surface of anodic electrode. The isotropic channels were constructed by the interconnected and uniformly distributed free volumes in the polymer matrix, and were expected to be swelled by solvent molecules and anions of lithium salt and to allow Li+ ions to pass through onto the electrode surface. As a result, dendrite-free morphology of deposited lithium was observed. The stabilized interface arose from the PSf film was verified by the promoted performances of Cu|Li cells and steady voltage polarization of Li|Li cells. The full cell with PSf coated anode exhibited excellent cyclability (85% capacity retention rate over 400 cycles at 1 C) and an outstanding rate capability (117 mAh g−1 at 5 C). The beneficial performances were further verified by the EIS results. This work provides a new strategic idea to settle the dendritic problems of Li metal anodes.

A novel polysulfone (poly-AF) and nanocomposite (poly-AF/Sep) membranes thereof were prepared successfully by incorporation of hydrophilic nanorods sepiolite into the polymeric matrix for application in water desalination via reverse osmosis. A novel poly-AF was prepared using a new monomeric pyridine-based diol which itself was synthesized, characterized, and reacted with bis(4-fluorophenyl) sulfone as a dihalide monomer. To improve the hydrophilicity of poly-AF, 1, 3, 5, 7, and 10 wt% sepiolite nanorods were introduced into it by sonication device to achieve a homogeneous solution. Poly-AF and nanocomposite solutions with 30 wt% concentration were used to prepare flat membranes on polyester sheets by non-solvent induced phase inversion through immersion precipitation method. The separation performances of the pristine poly-AF and poly-AF/Sep membranes were studied using evaluation of pure water flux and salt rejection of NaCl. Optimal results of pure water flux of 40.0 L m−2 h−1 and salt rejection of 99.1% were obtained at 30 bar with cross-flow filtration technique. In addition, the surface of membranes properties was characterized by field emission scanning electron microscopy, transmission electron microscopy, and atomic force microscopy.

The presented work is devoted to the development of a hybrid composite material – fiber metal laminate based on basalt fabric (BF), with increased damping properties, due to the use of a new thermoplastic elastomer binder. The synthesis method and properties of the new polymer which is a multiblock copolymers of poly (urethaneamidoimide) is shown. The mechanical and damping characteristics of FML based on synthesized polymer were studied. Their properties were compared with polysulfone-based FML. The developed material has a high tan δ value in the temperature range from −25 to 150 °C.

Fouling resistance of ultrafiltration (UF) membranes is critical for their long-term usages in terms of stable performance, so convenient approaches to prepare fouling-resistant membranes are always anticipated. Herein, we demonstrate the facile fabrication of antifouling polysulfone-block-poly(ethylene glycol) (PSF-b-PEG, SFEG) composite membranes. SFEG layer was coated onto macroporous supports and cavitated by immerging them in acetone/n-propanol following the mechanism of selective swelling induced pore generation. Thus-produced SFEG membranes possessed high permeance and excellent mechanical strength. Meanwhile, the structures and separation performances of the SFEG layers can be continuously tuned through simply changing swelling durations. More importantly, the hydrophilic PEG chains were spontaneously enriched onto the pore walls through swelling treatment, endowing intrinsic antifouling property to the SFEG membranes. Bovine serum albumin (BSA)/humic acid (HA) fouling tests proved the prominent fouling resistance of SFEG membranes, and the fouling resistance is expected to be long-standing because of the firm connection between PEG chains and PSF matrix by covalent bonding.

Biogas production has been globally promoted due to the need for renewable energy. Membrane gas separation is one of the most potential technologies for separating impurity and inert gases from the biogas to meet the fuel standard. Membranes with high selectivity and high permeability are most desirable in membrane gas separation. This study aims to develop the composite hollow fiber membrane for CO2 separation from CO2/CH4 mixture. The synthesized composite membranes were composed of a support layer of polysulfone (PSF) and a selective layer, containing poly-block-amide (PEBAX1657) and modified zeolite Y as the filler. The effects of filler loading at 0, 5, 10, 15, and 20 on membrane properties and performance were investigated. The defect-free composite membranes were successfully obtained in all filler loadings.

A novel polysulfone (PSF) mixed matrix membrane blended by polyethylene glycol (5 and 10 wt.%) was synthesized in which the graphene hydroxyl (G-OH) nanoparticles incorporated. Polyethelene glycol (PEG) as an affordable additive provides a proper CO2 affinity. Moreover, the G-OH nanoparticles was enhanced the CO2 permeability in MMMs through Lewis acid- base interaction between electron withdrawing oxygen of −OH and CO2. First, PSF membrane was modified via adding PEG. Obtained results were shown that the CO2 permeability increased significantly from 15.9 Barrer (for neat PSF) to 28.2 Barrer (for PSF/PEG (10 wt%), while a fairly significant increase in CO2/CH4 selectivity (from 12.23 for neat PSF to 12.81 for PSF/PEG (10 wt%) at the pressure of 2 bar and temperature of 35 °C. Second, the G-OH nanoparticles were incorporated (1, 2, 3, 4 and 5 wt%) into the both PSF/PEG (5 wt%) and PSF/PEG (10 wt%) matrix to prepare the PSF/PEG/G-OH MMMs. Results showed the best CO2/CH4 selectivity was obtained at 5 wt% loading of G-OH for both PSF/PEG (5 wt%) and PSF/PEG (10 wt%) were 20.94 and 22.39, respectively; at pressure of 8 bar. The separation properties of membranes were also evaluated at higher feed pressure and the obtained results were discussed.

It is well known that facilitated transport membranes (FTMs) containing CO2 carriers have high CO2 permeability and excellent permselectivity of CO2 over other light gases. The major challenge in developing FTMs for practical applications is the formation of a separation layer containing CO2 carriers on a support membrane. In this research, we prepared composite membranes by forming a dense gel layer containing glycine as the CO2 carrier on polysulfone (PSf) and ceramic (α-alumina) support membranes. Because of the smaller pore size of the PSf support membrane, the gel layer formed on the PSf membrane was thinner and had higher CO2 permeance than that formed on the alumina membrane. However, the CO2 permeabilities of the FTMs formed on the two support membranes showed different temperature dependences; the FTM formed on PSf membrane had higher CO2 permeability at elevated temperatures of more than ca. 350 K and lower CO2 permeability at low temperatures up to ca. 350 K than the FTM formed on alumina support. The different temperature dependences on the CO2 permeability resulted from the different properties of the gel layer formed on the support membranes. Improvement of the CO2 permeability of FTMs could be enabled by selecting an adequate support membrane.

The current investigation focus on the use of brown alga Turbinaria conoides (TC) and polysulfone immobilized Turbinaria conoides (PITC) for the biosorption of rare earth element Thulium (Tm(III)) from aqueous systems. To attain the highest removal of Tm(III), the process parameters including the equilibrium pH, Tm(III) concentration and biosorption time were optimized. The characterization techniques were used to analyse the morphological features and elemental analysis of the biosorbents. The isotherm models of selective two and three parameters were subjected to inspect the equilibrium data. The biosorption data fitted to the different biosorption kinetic models. Results illustrated that both TC and PITC displayed higher biosorption capacity of 200.5 and 157.9 mg/g, respectively. Through kinetic trials, we identified delay in equilibrium attainment for PITC and the data were described with intraparticle diffusion model. TC and PITC presented comparable results with biosorption equilibrium attained in 200 min, optimum equilibrium solution pH 5.0 and exhibited maximum biosorption capacity for the initial Tm(III) concentrations of 500 mg/L. Recovery studies represented that the maximum desorption efficiency attained using 0.01 M HCl and PITC presented potential uptake capacity of Tm(III) during the entire 10 biosorption–desorption cycles.

Long-term gas separation performance and stability are the predominant factors enabling successful implementation of mixed matrix membranes (MMMs) for large-scale industrial applications. This study highlights the integration of CNT and graphene into Polysulfone (PSf) matrix and studied the synergistic effect on the permeation characteristics of O2/N2 pair. An electrical alignment technique has adopted for the preparation of the MMMs by solution casting method. Also, the parent counterparts, including PSf/CNT and PSf/rGO systems have prepared. FTIR, UV, and EDS established the existence of membrane-forming materials. The electron micrographs confirmed uniform dispersion of the filler phase within the PSf matrix, thereby indicating an effectual increase in the permeation characteristics. The hybrid system exhibited improved mechanical and thermal stability against other tested membranes. The prepared membranes showed excellent O2 permeation with higher selectivity for N2, despite the minimal difference in molecular size. The hybrid system rendered uniform permeation coefficient for 120 h; also displayed excellent hydrothermal and chemical stabilities, thus establishing commercial potential.

This study focuses on the preparation of various polymeric nanofibers using new industrial production equipment – a wire electrospinning system. The disadvantages of each polymeric nanofiber were improved by mixing suitable polymer/polymer-solvent/solvent systems. A total of 9 types of polymers (polyamide, polyvinylidene fluoride, polyacrylonitrile, polyurethane, polysulfone, chitosan, cellulose acetate, polyvinyl butyral, and polycaprolactone) and their mixtures were electrospun using a wire electrospinning system. The resultant fiber surface morphology showed that the wire electrospinning method is suitable for the production of various polymers on an industrial scale. Moreover, polymer mixtures changed the adhesion properties, increased productivity and reduced the fiber diameter of nanofibers. Keywords: Nanofiber, Mass production, Nanospider, Chitosan, Cellulose acetate

This study reports landfill leachate treatment by the forward osmosis (FO) process using hydrogen peroxide (H2O2) for membrane cleaning. Although chemical cleaning is an effective method for fouling control, it could compromise membrane integrity. Thus, understanding the impact of chemical cleaning on the forward osmosis membrane is essential to improving the membrane performance and lifespan. Preliminary results revealed a flux recovery of 98% in the AL-FS mode (active layer facing feed solution) and 90% in the AL-DS (draw solution faces active layer) using 30% H2O2 solution diluted to 3% by pure water. The experimental work investigated the effects of chemical cleaning on the polyamide active and polysulfone support layers since the FO membrane could operate in both orientations. Results revealed that polysulfone support layer was more sensitive to H2O2 damage than the polyamide active at a neutral pH. The extended exposure of thin-film composite (TFC) FO membrane to H2O2 was investigated, and the active layer tolerated H2O2 for 72 h, and the support layer for only 40 h. Extended operation of the TFC FO membrane in the AL-FS based on a combination of physical (hydraulic flushing with DI water) and H2O2 was reported, and chemical cleaning with H2O2 could still recover 92% of the flux.

Background In order to improve the selective separation performance of the membrane for Li+ and enhance the separation efficiency, a crown ether functionalized polysulfone membrane was prepared in this paper, and the Li+ was separated by electrodialysis process. Methods Chloromethylated polysulfone (CMPSf) was used as the base membrane, 4′-aminobenzo-12-crown-4-ether (AB12C4) was in-situ grafted onto the surface of CMPSf membrane to obtain the PSf-sg-AB12C4 membrane. The chemical structure of the membrane surface was characterized by ATR-FTIR and XPS. The surface and cross-sectional morphologies of the membrane were characterized by FESEM. The PSf-sg-AB12C4 membrane was used for selective separation of Li+ by membrane coupling with electric field. Fingings The results show that the CMPSf membranes and the PSf-sg-AB12C4 porous membrane have almost no selective separation performance for Li+, while the PSf-sg-AB12C4 dense membrane can selectively separate Li+. After optimizing the conditions of voltage, ion concentration and solution pH, the separation factor of the PSf-sg-AB12C4 dense membrane for Mg2+ to Li+ is up to 32.6. In addition, the separation factors of coexisting ions such as Na+, K+, Ca2+ to Li+ are all higher than that of Mg2+ to Li+, suggesting that the PSf-sg-AB12C4 dense membrane is a promising material for selective separation of Li+ from brine.

The tactic of embedding functional nanomaterials into ultrafiltration (UF) membranes has been investigated in order to augment the integrated properties of the hybrid membranes. Mixing of hydrophilic inorganic nanoparticles or nanofillers into the polymeric membranes to form organic-inorganic nanocomposite membranes were found to be quite effective in improving membrane hydrophilicity. In the present study, polysulfone (PSf) membrane of three different compositions (9, 12, 18 wt%) in-situ immobilized with silver nanoparticles were fabricated using phase-inversion technique. The surface morphology of the membranes were studied by field emission scanning electron microscope (FESEM). The uniformity of the distributed nanoparticles and the elemental compositions were proved by energy dispersive x-ray Spectroscope (EDS). BET (Brunauer-Emmett-Teller), nitrogen adsorption measurement has revealed the increase in surface area from 10.15 to 18.85 m 2 /g for polysulfone membrane and 12.31 to 20.62 m 2 /g for silver-polysulfone (Ag-PSf) membrane. The surface charges of the fabricated membranes were studied using zeta potential measurements. Furthermore, water flux and sulfate rejection measurements were also carried out using a cross-flow membrane unit. Among the three different compositions, 12 wt% PSf-Ag membranes had significantly higher rejection rate than that of the other membranes.

High strength synthetic wastewater containing 5 mg L−1 of lead was studied for treatment using an A2O MBR system. The system showed 99% removal of ammonia and COD, a maximum removal of 52% of total phosphorus and an average minimum removal of 72% of total nitrogen. A maximum lead removal of 98% was achieved for hydraulic retention time (HRT) of 144 h, which decreased to 85% when the influent COD concentration was decreased. Mass balance for lead revealed that much of its removal was through accumulation by the biomass present in the anaerobic and anoxic tanks. Comparative study on virgin PSf and GO blended PSf membrane showed that the GO blended membrane lasted 1.4 times longer than the other. SEM-EDS of membranes showed lead peaks on the fouled and un-fouled sections of the membranes indicating the association of lead with the foulant and the role of membrane in lead separation. Good separation efficiency was achieved irrespective of the membranes used.