Development and characterization of novel charged surface modification macromolecule to polyethersulfone hollow fiber membrane with polyvinylpyrrolidone and water

Preserving nanoscale features in polymers during laser induced graphene formation using sequential infiltration synthesis

Direct lasing of polymeric membranes to form laser induced graphene (LIG) offers a scalable and potentially cheaper alternative for the fabrication of electrically conductive membranes. However, the high temperatures induced during lasing can deform the substrate polymer, altering existing micro- and nanosized features that are crucial for a membrane's performance. Here, we demonstrate how sequential infiltration synthesis (SIS) of alumina, a simple solvent-free process, stabilizes polyethersulfone (PES) membranes against deformation above the polymers' glass transition temperature, enabling the formation of LIG without any changes to the membrane's underlying pore structure. These membranes are shown to have comparable sheet resistance to carbon-nanotube-composite membranes. They are electrochemically stable and maintain their permeability after lasing, demonstrating their competitive performance as electrically conductive membranes. These results demonstrate the immense versatility of SIS for modifying materials when combined with laser induced graphitization for a variety of applications.

Co0.85Se Nanoparticles Encapsulated by Nitrogen-Enriched Hierarchically Porous Carbon for High-Performance Lithium-Ion Batteries

Coordination compound derivates (CCDs) have been widely applied in lithium-ion batteries (LIBs). However, the functionalization of CCDs with open structure and heteroatomic doping is still challenging. Herein, an effective functionalization strategy is presented to prepare a kind of CCD, where Co_0.85Se nanoparticles are encapsulated by nitrogen-enriched hierarchically porous carbon (CS/NPC) based on the heat treatment of a cobalt-complexed hexamethylolmelamine-polyvinylpyrrolidone resin (Co²⁺/HPR). The abundant free volume and enriched N species of the HPR are responsible for the hierarchically porous configuration and high N-doping of the composites. By controlling the content of cobalt salt and the heating rate, high specific surface area (440.7 m² g^-1), high N-doping (8.54 atom %), and suitable mass loading of Co_0.85Se (55.5%) were simultaneously achieved in CS-2/NPC-5, which delivers high reversible capacity (758.5 mAh g^-1 at 0.1 A g^-1), outstanding rate capability (401.7 mAh g^-1 at 5 A g^-1), and excellent cycling durability (638.4 mAh g^-1 at 1 A g^-1 after 200 cycles), suggesting a promising candidate for LIB anode materials.

Short-term stability assessment for the analysis of emerging contaminants in seawater

This paper describes the stability study performed in seawater and seawater extracts (spiked at ~ 200 ng/L) for 23 emerging contaminants. Four different alternatives were tested at six different times (0, 3, 10, 17, 24 and 31 days): (i) seawater at 4 °C, (ii) mixed-mode solid-phase extraction cartridge (Bond Elute Plexa and Strata X-AW) stored at - 20 °C, (iii) polyethersulfone hollow fibre stored at - 20 °C and (iv) methanol extracts once the samples were extracted from PES hollow fibre and stored at - 20 °C. Moreover, the integrity of the supporting polymeric phases was studied by Raman, optical microscopy, differential scanning calorimetric and thermogravimetric analysis. As may be expected, seawater samples showed the lowest stability (losses between 21 and 99%) while methanol extract provides stable results (losses < 30%) over the tested period. In the case of solid-phase cartridges, the stability profile showed an average loss of 7% while, in polyethersulfone hollow fibres, losses up to 58% were observed. Finally, we were able to relate the lower efficiency of polyethersulfone fibres with the wettability of this material based on the thermogravimetric analysis.

Preparation of SGO-modified nanofiltration membrane and its application in SO42- and Cl- separation in salt treatment

The lack of fresh water in the world makes the search for an effective method to decontaminate water an urgent priority. An important step is to remove different multivalent ions in salt treatment. Nanofiltration (NF) has been used for treating water containing different kinds of salts. In this work, sulfonate group-modified graphene oxide (SGO) was prepared, and added during the interfacial polymerization (IP) reaction to prepare SGO-modifiedNF membranes (PA-SGO). The chemical composition, structure and surface properties of PA and PA-SGO membranes were characterized by FT-IR, XPS, SEM, AFM, contact angle and zeta potential measurements. Their water flux, salt rejection and anti-fouling abilities were investigated systematically. The testing results showed that the water flux of PA-SGO (0.03% SGO) was 45.85 LMH under a pressure of 0.2 MPa, and the salt rejection varied in the order of Na₂SO₄ (98.99%) > MgSO₄ (91.25%) > MgCl₂ (42.27%) > NaCl (21.96%). An anti-fouling experiment indicated that the PA-SGO membrane had good anti-fouling properties because of its decreased roughness and increased hydrophilicity and electronegativity. The PA-SGO membrane has good potential for use in removing salt ions from water.

Recent advances in hydrophilic modification and performance of polyethersulfone (PES) membrane via additive blending

The blending of additives in the polyethersulfone (PES) matrix is an important approach in the membrane industry to reduce membrane hydrophobicity and improve the performance (flux, solute rejection, and reduction of fouling). Several (hydrophilic) modifications of the PES membrane have been developed. Given the importance of the hydrophilic modification methods for PES membranes and their applications, we decided to dedicate this review solely to this topic. The types of additives embedded into the PES matrix can be divided into two main categories: (i) polymers and (ii) inorganic nanoparticles (NPs). The introduced polymers include polyvinylpyrrolidone, chitosan, polyamide, polyethylene oxide, and polyethylene glycol. The introduced nanoparticles discussed include titanium, iron, aluminum, silver, zirconium, silica, magnesium based NPs, carbon, and halloysite nanotubes. In addition, the applications of hydrophilic PES membranes are also reviewed. Reviewing the research progress in the hydrophilic modification of PES membranes is necessary and imperative to provide more insights for their future development and perhaps to open the door to extend their applications to other more challenging areas.

Characterization and Separation Performance of a Novel Polyethersulfone Membrane Blended with Acacia Gum

Novel polyethersulfone (PES) membranes blended with 0.1-3.0 wt. % of Acacia gum (AG) as a pore-former and antifouling agent were fabricated using phase inversion technique. The effect of AG on the pore-size, porosity, surface morphology, surface charge, hydrophilicity, and mechanical properties of PES/AG membranes was studied by scanning electron microscopy (SEM), Raman spectroscopy, contact angle and zeta potential measurements. The antifouling -properties of PES/AG membranes were evaluated using Escherichia coli bacteria and bovine serum albumine (BSA). The use of AG as an additive to PES membranes was found to increase the surface charge, hydrophilicity (by 20%), porosity (by 77%) and permeate flux (by about 130%). Moreover, PES/AG membranes demonstrated higher antifouling and tensile stress (by 31%) when compared to pure PES membranes. It was shown that the prepared PES/AG membranes efficiently removed lead ions from aqueous solutions. Both the sieving mechanism of the membrane and chelation of lead with AG macromolecules incorporated in the membrane matrix contributed to lead removal. The obtained results indicated that AG can be used as a novel pore-former, hydrophilizing and antifouling agent, as well as an enhancer to the mechanical and rejection properties of the PES membranes.

Preparation and characterization of novel alkali-resistant nanofiltration membranes with enhanced permeation and antifouling properties: the effects of functionalized graphene nanosheets

In this study, novel alkali-resistant NF membranes were developed by incorporating two kinds of functionalized graphene nanosheets into PES matrix. PES–SG demonstrated more great promise due to its superior permeability and antifouling performance.

Surface modification of SiO2 nanoparticles and its impact on the properties of PES-based hollow fiber membrane

The FTIR spectra for SiO₂-SDS nanoparticles clearly show the detection of SDS functional groups in surface-modified SiO₂ and confirm the successful modification of the nanoparticles surface.

Layer by layer assembly of sulfonic poly(ether sulfone) as heparin-mimicking coatings: scalable fabrication of super-hemocompatible and antibacterial membranes

In this study, super-hemocompatible and antibacterial polymeric membranes with surface coated nanofilms were fabricated by LBL assembly of water-soluble heparin-mimicking polymer and quaternized chitosan.

Direct synthesis of heparin-like poly(ether sulfone) polymer and its blood compatibility

In this study, heparin-like poly(ethersulfone) (HLPES) was synthesized by a combination of polycondensation and post-carboxylation methods, and was characterized by Fourier transform infrared spectroscopy, nuclear magnetic resonance hydrogen spectrum and gel permeation chromatography. Owing to the similar backbone structure, the synthesized HLPES could be directly blended with pristine PES at any ratios to prepare PES/HLPES membranes. After the introduction of HLPES, the microscopic structure of the modified PES membranes was changed, while the hydrophilicity was significantly enhanced. Bovine serum albumin and bovine serum fibrinogen adsorption, activated partial thromboplastin time, thromb time and platelet adhesion for the modified PES membranes were investigated. The results indicated that the blood compatibility of the PES/HLPES membranes was significantly improved compared with that of pristine PES membrane. For the PES/HLPES membranes, obvious decreases in platelet activation on PF-4 level, in complement activation on C3a and C5a levels, and in leukocytes activation on CD11b levels were observed compared with those for the pristine PES membrane. The improved blood compatibility of the PES/HLPES membrane might due to the existence of the hydrophilic groups (-SO3Na, -COONa). Furthermore, the modified PES membranes showed good cytocompatibility. Hepatocytes cultured on the PES/HLPES membranes presented improved growth in terms of SEM observation, MTT assay and confocal laser scanning microscope observation compared with those on the pristine PES membrane. These results indicate that the PES/HLPES membranes present great potential in blood-contact fields such as hemodialysis and bio-artificial liver supports.

Poly(amidoamine) dendronized hollow fiber membranes: synthesis, characterization, and preliminary applications as drug delivery devices

Poly(amidoamine) (PAMAM) dendrons were prepared from hollow fiber membranes (HFM) consisting of bromomethylated poly(2,6-dimethyl-1,4-phenylene oxide) (BPPO) in a stepwise manner. The prepared HFM were characterized by Fourier transform infrared spectroscopy, elemental analysis, and scanning electron microscopy. The drug loading efficiency and release behavior of the PAMAM dendronized HFM were evaluated using sodium salicylate, sodium methotrexate, and Congo red as model drugs. The results suggest that PAMAM dendronized HFM can be effectively loaded with a variety of drugs and prolong the release of these drugs. The drug loading and release characteristics of the HFM depend on the generation of PAMAM dendrons grafted on the membranes. The prepared PAMAM dendronized BPPO HFM are promising scaffolds in drug delivery and tissue engineering.