Embedded three spinel ferrite nanoparticles in PES-based nano filtration membranes with enhanced separation properties

In this study, three types of ferrites nanoparticles including CoFe2O4, NiFe2O4, and ZnFe2O4 were synthesized by microwave-assisted hydrothermal method. The X-ray diffraction analysis (XRD), Fourier transform infrared spectroscopy (FTIR), and field emission scanning electron microscopy (FESEM) were employed to analyze synthesized nanoparticles and fabricated membranes. The morphology of membrane surface was investigated by surface images. The ability of ferrite nanoparticles was evaluated to the separation of sodium salt and heavy metals such as Cr2+, Pb2+, and Cu2+ from aqueous solutions. The modified membrane showed the enhancement of membrane surface hydrophilicity, porosity, and mean pore size. The results revealed a significant increase in pure water flux: 152.27, 178, and 172.68 L·m−2·h−1 for PES/0.001 wt% of CoFe2O4, PES/0.001 wt% NiFe2O4, and PES/0.001 wt% ZnFe2O4 NPs, respectively. Moreover, Na2SO4 rejection was reached 78% at 0.1 wt% of CoFe2O4 NPs. The highest Cr (II) rejection obtained 72% for PES/0.001 wt% of NiFe2O4 NPs while it was 46% for the neat PES membrane. The Pb(II) rejection reached above 75% at 0.1 wt% of CoFe2O4 NPs. The Cu(II) rejection was obtained 75% at 0.1 wt% of CoFe2O4 NPs. The ferrite NPs revealed the high potential of heavy metal removal in the filtration membranes.

Improvement of Properties and Performances of Polyethersulfone Ultrafiltration Membrane by Blending with Bio-Based Dragonbloodin Resin

Polyethersulfone (PES) is the most commonly used polymer for membrane ultrafiltration because of its superior properties. However, it is hydrophobic, as such susceptible to fouling and low permeation rate. This study proposes a novel bio-based additive of dragonbloodin resin (DBR) for improving the properties and performance of PES-based membranes. Four flat sheet membranes were prepared by varying the concentration of DBR (0–3%) in the dope solutions using the phase inversion method. After fabrication, the membranes were thoroughly characterized and were tested for filtration of humic acid solution to investigate the effect of DBR loading. Results showed that the hydrophilicity, porosity, and water uptake increased along with the DBR loadings. The presence of DBR in the dope solution fastened the phase inversion, leading to a more porous microstructure, resulted in membranes with higher number and larger pore sizes. Those properties led to more superior hydraulic performances. The PES membranes loaded with DBR reached a clean water flux of 246.79 L/(m2·h), 25-folds higher than the pristine PES membrane at a loading of 3%. The flux of humic acid solution reached 154.5 ± 6.6 L/(m2·h), 30-folds higher than the pristine PES membrane with a slight decrease in rejection (71% vs. 60%). Moreover, DBR loaded membranes (2% and 3%) showed an almost complete flux recovery ratio over five cleaning cycles, demonstrating their excellent antifouling property. The hydraulic performance could possibly be enhanced by leaching the entrapped DBR to create more voids and pores for water permeation.

Electrospun Magnetic Nanocellulose–Polyethersulfone-Conjugated Aspergillus oryzae Lipase for Synthesis of Ethyl Valerate

A novel greener MNC/PES membrane was developed through an electrospinning technique for lipase immobilization to catalyze the synthesis of ethyl valerate (EV). In this study, the covalent immobilization of Aspergillus oryzae lipase (AOL) onto an electrospun nanofibrous membrane consisting of magnetic nanocellulose (MNC) and polyethersulfone (PES) to produce EV was statistically optimized. Raman spectroscopy, Fourier-transform infrared spectroscopy: attenuated total reflection, field emission scanning electron microscopy, energy dispersive X-ray spectroscopy, thermal gravimetric analysis (TGA), and differential thermal gravimetric (DTG) of MNC/PES-AOL demonstrated that AOL was successfully immobilized onto the fibers. The Taguchi design-assisted immobilization of AOL onto MNC/PES fibers identified that 1.10 mg/mL protein loading, 4 mL reaction volume, 250 rpm stirring rate, and 50 °C were optimal to yield 72.09% of EV in 24 h. The thermal stability of MNC/PES-AOL was improved by ≈20% over the free AOL, with reusability for up to five consecutive esterification cycles while demonstrating an exceptional half-life of 120 h. Briefly, the electrospun MNC/PES fibers that immobilized AOL showed promising applicability in yielding relatively good EV levels. This study suggests that using MNC as fillers in a PES to improve AOL activity and durability for a longer catalytic process could be a viable option.

Effect of carbon nanotubes loading and pressure on the performance of a polyethersulfone (PES)/carbon nanotubes (CNT) membrane

This paper focuses on modifying a PES membrane with acid-functionalised carbon nanotubes (CNT) for industrial wastewater treatment. Embedding acid functionalised carbon nanotubes (CNTs) within the membrane matrix would increase the membrane flux by increasing the membrane pore size and surface area, rejection and thermal stability. Pure PES membranes were prepared by phase inversion method and infused with CNTs at 2.5, 5, 7.5 and 10 wt% loading to fabricate PES/2.5 wt% CNT, PES/5 wt% CNT, PES/7.5 wt% CNT and PES/10 wt% CNT membranes respectively. Characterisation was performed using Transmission Electron Microscopy (TEM) to determine CNT morphology, X-ray Diffraction (XRD) to determine the functional groups attached to CNTs, Thermogravimetric Analysis (TGA) to determine the thermal stability of the membranes, Scanning Electron Microscope (SEM) to determine membrane morphology, Bunauer-Emmett-Teller (BET) method to obtain pore size information and Contact Angle (CA) to determine the membrane hydrophilicity. Membrane performance was then evaluated with a dead-end stirred cell using industrial wastewater containing traces of Cu, Fe, Ni, Zn and Cl. Permeate flux results showed a direct proportion relationship with increasing CNT loading and increasing pressure (100 kPa, 300 kPa, 500 kPa, 700 kPa, 900 kPa and 1100 kPa). PES/5 wt% CNT membrane showed the most enhanced performance compared to the other membranes, achieving reasonably high flux of 43.7 L/m2h and rejection of 89.6% Cu, 100% Fe, 90.5% Ni, 68.8% Zn and 99.99% Cl at 300 kPa. The results obtained showed that the PES membrane embedded with functionalised CNTs could be used for the treatment of industrial wastewater.

Fabrication of Polyethersulfone (PES) Membrane Incorporated with Graphitic Carbon Nitride (g-C3N4) Nanoparticles in Palm Oil Mill Effluent (POME) Wastewater Treatment

Backed by the evolution in the nanotechnology field, membrane modified with nanoparticles as an additive has become increasingly prominent nowadays. The enormous potential of graphitic carbon nitride (g-C3N4) photocatalyst in wastewater treatment has been disclosed extensively. In this study, 4 Polyethersulfone (PES) membranes with different concentration of g-C3N4nanoparticles as additive were fabricated and their performances were investigated. Scanning Electron Microscopy (SEM) analysis showed that the membrane top surface layer was getting denser with the higher g-C3N4nanoparticles concentration which subsequently decreased the membrane mean pore size, porosity and flux. However the membrane with higher additive concentration was demonstrated a better improvement in anti-fouling properties where the flux recovery ratio (FRR) of the membranes showed an uptrend movement from 23.43% (membrane without additive) to 64.64% (membrane with 6 wt.% of additive). The enhancement of COD and colour removal rate from 61.50 % to 66.50 % and 78.75 % to 83.75 % was also observed in this study where the finding has signified the increased g-C3N4 nanoparticles concentration was constructive in PES membrane modification.

Antimicrobial Hydrophilic Membrane Formed by Incorporation of Polymeric Surfactant and Patchouli Oil

Membrane properties are highly affected by the composition of the polymer solutions that make up the membrane material and their influence in the filtration performance on the separation or purification process. This paper studies the effects of the addition of pluronic (Plu) and patchouli oil (PO) in a polyethersulfone (PES) solution on the membrane morphology, membrane hydrophilicity, and filtration performance in the pesticide removal compound in the water sample. Three types of membranes with the composition of PES, PES + Plu, and PES + Plu + patchouli oil were prepared through a polymer phase inversion technique in an aqueous solvent. The resulting membranes were then analyzed and tested for their mechanical properties, hydrophilicity, antimicrobial properties, and filtration performance (cross-flow ultrafiltration). The results show that all of the prepared membranes could reject 75% of the pesticide. The modification of the PES membrane with Plu was shown to increase the overall pore size by altering the pore morphology of the pristine PES, which eventually increased the permeation flux of the ultrafiltration process. Furthermore, patchouli oil added antimicrobial properties, potentially minimizing the biofilm formation on the membrane surface.