High-Flux, Antifouling Hydrophilized Ultrafiltration Membranes with Tunable Charge Density Combining Sulfonated Poly(ether sulfone) and Aminated Graphene Oxide Nanohybrid

In this work, a new protocol was developed for creating charge-tuned, hydrophilic hybrid ultrafiltration (UF) membranes with high flux, rejection rate, and fouling resistance. The membranes were fabricated using a combination of sulfonated poly(ether sulfone) (SPES) and aminated graphene (GO-SiO -NH ) nanohybrid via the non-solvent-induced phase separation (NIPS) method. The GO-SiO -NH nanohybrid was first synthesized using GO nanosheets and 3-aminopropyl triethoxysilane (APTES) through the covalent condensation reaction at 80 °C and was thoroughly characterized. Then, 2-8 wt% of the nanohybrid was incorporated into the matrix of SPES for the fabrication of the hybrid membranes. The resulting membranes were characterized using an electrokinetic analyzer, a contact angle goniometer, and Raman, field emission scanning electron microscopy-energy-dispersive X-ray spectrometry (FESEM-EDX), and atomic force microscopy experiments. The porosity, charge density, and surface morphology were altered, and the hybrid membranes became more hydrophilic after the incorporation of the nanohybrid. The pure water flux of the hybrid membranes systematically increased with the loading amount of the nanohybrid. The pure water flux of the hybrid membrane containing 6 wt% GO-SiO -NH nanohybrid at a 2 bar feed pressure was 537 L m h , about 3-fold that of pristine membrane (186 L m h ). The fouling resistance of the hybrid membranes was evaluated and confirmed using several representative foulants, including bovine serum albumin, humic acid, sodium alginate, and a synthetic solution of natural organic matter (NOM). The fabricated membranes were capable of removing more than 97% of NOM, without a compromise of their rejection rate

3D printed photocatalytic feed spacers functionalized with β-FeOOH nanorods inducing pollutant degradation and membrane cleaning capabilities in water treatment

[Display omitted] •Novel photocatalytic 3D printed feed spacers developed for (waste)water treatment.•β-FeOOH nanorods were mineralized on PDA/PEI-coated polyamide spacer.•The spacers degraded methylene blue and 4-nitrophenol in the feed during filtration.•Photocatalytic spacer also cleaned the organic foulants deposited on the membrane.•New approach enables a shift to spacer-centered photocatalytic membrane systems. A novel 3D printed photocatalytic feed spacer was developed for use in membrane-based water and wastewater filtration systems. The spacer fulfilled two new functions; degradation of membrane-permeating pollutants in the feed and membrane cleaning, in addition to its basic role as membrane support. The spacer, designed based on a triply periodic minimal surface architecture, was coated with polydopamine-polyethyleneimine, on which a photocatalytic layer of β-FeOOH nanorods was mineralized. The photocatalytic performance of the spacer was demonstrated through the degradation of methylene blue and 4-nitrophenol, both in batch and crossflow ultrafiltration (UF) modes. The spacer also exhibited the ability to clean the membrane surface of three organic foulants (humic acid (HA), sodium alginate (SA) and bovine serum albumin (BSA)), with a flux recovery ratio of 92 %, 60 %, and 54 % achieved for SA, HA, and BSA, respectively. This enables a shift to spacer-centered photocatalytic membrane system approach in water and wastewater treatment

Polydopamine-coated graphene oxide nanosheets embedded in sulfonated poly (ether sulfone) hybrid UF membranes with superior antifouling properties for water treatment

A novel high-performance hybrid ultrafiltration (UF) membrane was fabricated by blending polydopamine-coated graphene oxide (PDGO) nanosheets with sulfonated poly(ether sulfone) (SPES) via phase inversion method and tested for the removal of natural organic matter (humic acid; HA) from aqueous solution. The PDGO nanosheets were synthesized via self-polymerization of dopamine with GO nanosheets in alkaline tris-buffer solution at room temperature for 24 h and were fully characterized. Hybrid SPES membranes were prepared by incorporating 1–10 wt% of PDGO, which were further characterized by Raman spectroscopy, surface zeta potential, and field emission scanning electron microscopy to confirm membrane stability without any defects even by adding up to 10 wt%, of PDGO nanosheets. The membranes demonstrated a significant increase in hydrophilicity, water flux, and retention rate for HA (RHA). For instance, water permeability with 5 wt% PDGO (M5) (680.7 L m−2 h−1 bar−1) was ca. 1.8-folds that of the pristine SPES membrane (380.8 L m−2 h−1 bar−1), while maintaining an HA rejection (RHA) of 91.7% for a 50 ppm HA feed solution. This was accompanied by a distinct increase in surface hydrophilicity of M5, which showed a water contact angle of 27.8°, well below that of pristine SPES membrane (59.1°). The hybrid UF membranes also demonstrated a significant reduction in HA adhesion onto the membrane surface along with a superior antifouling performance for the membrane containing 10 wt% PDGO, giving irreversible fouling ratio (Rir) of only 6.9% compared to 32.7% for the pristine membrane