Influence of Polymer Solvents on the Properties of Halloysite-Modified Polyethersulfone Membranes Prepared by Wet Phase Inversion

Abstract

Ultrafiltration polyethersulfone (PES) membranes were prepared by wet phase inversion. Commercial halloysite nanotubes (HNTs) in the quantities of 0.5 wt% vs. PES (15 wt%) were introduced into the casting solution containing the polymer and different solvents: N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMA), or 1-methyl-2-pyrrolidinone (NMP). The type of solvent influenced the membranes’ morphology and topography, as well as permeability, separation characteristics, and antifouling and antibacterial properties. The membranes prepared using DMA exhibited the loosest cross-section structure with the thinnest skin and the roughest surface, while the densest and smoothest were the DMF-based membranes. The advanced contact angles were visibly lower in the case of the membranes prepared using DMF compared to the other solvents. The highest water permeability was observed for the DMA-based membranes, however, the most significant effect of the modification with HNTs was found for the NMP-based series. Regardless of the solvent, the introduction of HNTs resulted in an improvement of the separation properties of membranes. A noticeable enhancement of antifouling performance upon application of HNTs was found only in the case of DMF-based membranes. The study of the antibacterial properties showed that the increase in surface roughness had a positive effect on the inhibition of E. coli growth.

Graphene oxide‐enhanced polyethersulfone/polysulfone forward osmosis membranes for Suez Canal water desalination

“…By the addition of GO into the casting solution, the membrane morphology was altered, changing from a wider finger‐like structure to thinner finger‐like than the pristine membrane. This is because the hydrophilic property of GO causes the solvent (NMP) and nonsolvent (water) to separate more quickly in the coagulation bath (instantaneous demixing) 66 . This results in the formation of more finger‐like structures 53,67 .…”

“…This is because the hydrophilic property of GO causes the solvent (NMP) and nonsolvent (water) to separate more quickly in the coagulation bath (instantaneous demixing). 66 This results in the formation of more finger-like structures. 53,67 Additionally, the spongy sublayer thickness increases by increasing the concentration of GO (up to 0.04 wt%), Figure 4D-O.…”

Photocatalytic Zinc Oxide Nanoparticles in Antibacterial Ultrafiltration Membranes for Biofouling Control

“…The ACA measures a general surface’s tendency to be wetted by a liquid, indicating its hydrophilic or hydrophobic nature. In contrast, the RCA is a measure of relative hydrophilicity [ 67 ], which assesses how effectively the surface either retains a liquid or causes it to bead up and retract, reflecting its repellent or retentive characteristics.…”

Preparation of highly selective PSf/ZnO/PEG400 tight ultrafiltration membrane for dyes removal

“…The polymeric tight UF membranes are generally prepared by several methods, including crosslinking, 11 interfacial polymerization, 27 and phase inversion methods 28–31 . Among these methods, phase inversion is considered as a simple method.…”

“…26 The polymeric tight UF membranes are generally prepared by several methods, including crosslinking, 11 interfacial polymerization, 27 and phase inversion methods. [28][29][30][31] Among these methods, phase inversion is considered as a simple method. This method involves separating homogenous (one phase) membrane solutions into two phases, namely rich polymer and lean polymer.…”