Preparation of Antifouling Nanofiltration Membrane via Interfacial Polymerization of Fluorinated Polyamine and Trimesoyl Chloride

Abstract

AbstractsA novel fluorinated amine monomer (CF 3 (CF 2 ) 6 CONH(CH 2 CH 2 NH) 2 CH 2 CH 2 NH 2 , fluorinated polyamine, FPA) was synthesized and utilized to perform interfacial polymerization with trimesoyl chloride (TMC), producing thin-film composite (TFC) nanofiltration (NF) membranes with low surface free energy. Filtration experiments were performed using simulated brackish water (1.0 g/L of salt) and simulated dye wastewater (0.1 g/L of dyes). The membrane prepared under optimal conditions exhibited a flux of 12.9 L/(m 2 h) while the rejection of orange GII reached 94.7% under 0.2 MPa. The antifouling experiment results verified that the resultant membrane (surface free energy as low as 23.0 mJ/m 2 ) could effectively resist and drive off foulants such as bovine serum albumin (BSA), humic acid (HA) and oil due to the lower adhesion force between foulants and membrane. Excellent antifouling property of the resultant membrane (minimal value of total flux decline ratio ~9.1 %, maximum value of flux recovery ratio 99.8 %) would promote the application of nanofiltration in wastewater treatment.

Graphene oxide polypiperazine-amide nanofiltration membrane for improving flux and anti-fouling in water purification

“…The relationship between Stokes radius, r s (nm) and molecular weight, M w (g mol À1 ) of neutral solutes ( [45][46][47][48][49] were used to test the anti-fouling property of the PPA/GO composite NF membrane. The permeate uxes were obtained with variation of time.…”

Probing the charged nature and ion-exclusion mechanism of fluorine-enriched non-ionogenic polyamide derived thin film composite nanofiltration membranes

“…The bands with lower intensities located at 1375 and 1373 cm À1 correspond to the C-N stretching vibration (n C-N ) of tertiary amide segments of the polyamide structures. 31,36,37 The peaks with higher intensities appearing around 1243 cm À1 and the shoulder peak appearing at 1166 cm À1 for both the membranes are assigned to the symmetric (n Sym. ) and asymmetric (n Asym. )…”

“…[27][28][29] In contrast, this kind of functional interference in the structural features is quite expected with the existing varying poly(piperazineamide) structures, wherein residual carboxyl groups appeared through trimesoyl chloride type monomers. 25,[27][28][29]31 The weak and broad absorption bands around 3000 cm À1 however showed the very low water content, because of the polymer structure's enrichment with fluorine. The XPS survey-scan spectra of the membranes' skin layers, reported in Fig.…”

“…29 Fluorinated aromatic or semi-aromatic polyamides, derived using different fluorinated amines and ionogenic aromatic acyl chloride monomers, have been shown to exhibit Donnanexclusion of ions for nanofiltration purposes. [30][31][32][33] Developing a polyamide structure of low surface free energy by the use of a fluorinated polyamine has also become an important area of materials research for fouling-resistant membranes. [30][31][32][33] Structural susceptibility of aromatic polyamides, being a major issue in membrane stability, is known to happen through electrophilic substitution, via N (amidic)-chlorination and subsequent aromatic ring-chlorination (Orton rearrangement).…”

“…[30][31][32][33] Developing a polyamide structure of low surface free energy by the use of a fluorinated polyamine has also become an important area of materials research for fouling-resistant membranes. [30][31][32][33] Structural susceptibility of aromatic polyamides, being a major issue in membrane stability, is known to happen through electrophilic substitution, via N (amidic)-chlorination and subsequent aromatic ring-chlorination (Orton rearrangement). 34,35 It is a serious concern with the polyamide class of polymers that they are poor chlorine-tolerant candidates under an oxidative environment.…”