Correlating PSf Support Physicochemical Properties with the Formation of Piperazine-Based Polyamide and Evaluating the Resultant Nanofiltration Membrane Performance

Abstract

Abstract:Membrane support properties influence the performance of thin-film composite nanofiltration membranes. We fabricated several polysulfone (PSf) supports. The physicochemical properties of PSf were altered by adding polyethylene glycol (PEG) of varying molecular weights (200-35,000 g/mol). This alteration facilitated the formation of a thin polyamide layer on the PSf surface during the interfacial polymerization reaction involving an aqueous solution of piperazine containing 4-aminobenzoic acid and an organic solution of trimesoyl chloride. Attenuated total reflectance-Fourier transform infrared validated the presence of PEG in the membrane support. Scanning electron microscopy and atomic force microscopy illustrated that the thin-film polyamide layer morphology transformed from a rough to a smooth surface. A cross-flow filtration test indicated that a thin-film composite polyamide membrane comprising a PSf support (TFC-PEG20k) with a low surface porosity, small pore size, and suitable hydrophilicity delivered the highest water flux and separation efficiency (J = 81.1 ± 6.4 L·m −2 ·h −1 , R Na2SO4 = 91.1% ± 1.8%, and R NaCl = 35.7% ± 3.1% at 0.60 MPa). This membrane had a molecular weight cutoff of 292 g/mol and also a high rejection for negatively charged dyes. Therefore, a PSf support exhibiting suitable physicochemical properties endowed a thin-film composite polyamide membrane with high performance.

Optimal Performance of Thin-Film Composite Nanofiltration-Like Forward Osmosis Membranes Set Off by Changing the Chemical Structure of Diamine Reacted with Trimesoyl Chloride through Interfacial Polymerization

“…Figure 7 compares water contact angle data for PSf and TFC membranes. The PSf surface measured 58.31 ± 4.09° in contact angle, similar to that observed in our prior work [ 32 ]. The low contact angle for PSf might be ascribed to the addition of PEG20k, which entangled with the PSf chains.…”

Preparation of Porous Polymeric Membranes Based on a Pyridine Containing Aromatic Polyether Sulfone

“…NIPS has been extensively used for the fabrication of porous membranes based on hydrophobic matrices. Among them, polysulfone (PSF) and polyethersulfone (PES) are used as membrane matrices thanks to their high thermal and chemical stability, mechanical properties, high surface tension, excellent processibility, and film-forming properties [10,11,12,13,14,15]. However, their strong hydrophobic nature makes them prone to fouling, resulting in low water flux and limited lifetime.…”

Use of Ionic Liquids and Co-Solvents for Synthesis of Thin-Film Composite Membranes

“…It is known that the top-layer characteristics are influenced by the morphological and chemical properties of the support [ 6 , 38 , 39 , 40 , 41 , 42 ]. First, a higher hydrophilicity for the cross-linked PI support was observed (XL-PI (70.83° ± 1.82°) > PI (80.37° ± 2.37°) > PSf (90.50° ± 1.54°)), which is known to also affect the top-layer formation [ 18 , 31 , 39 , 40 , 41 , 43 , 44 ]. Next, cross-sectional SEM images of TFC membranes using the different ILs as organic phase were shown ( Figure 4 ).…”