Development of Antifouling Polysulfone Membranes by Synergistic Modification with Two Different Additives in Casting Solution and Coagulation Bath: Synperonic F108 and Polyacrylic Acid

Abstract

This study deals with the development of antifouling ultrafiltration membranes based on polysulfone (PSF) for wastewater treatment and the concentration and purification of hemicellulose and lignin in the pulp and paper industry. The efficient simple and reproducible technique of PSF membrane modification to increase antifouling performance by simultaneous addition of triblock copolymer polyethylene glycol-polypropylene glycol-polyethylene glycol (Synperonic F108, Mn =14 × 103 g mol−1) to the casting solution and addition of polyacrylic acid (PAA, Mn = 250 × 103 g mol−1) to the coagulation bath is proposed for the first time. The effect of the PAA concentration in the aqueous solution on the PSF/Synperonic F108 membrane structure, surface characteristics, performance, and antifouling stability was investigated. PAA concentrations were varied from 0.35 to 2.0 wt.%. Membrane composition, structure, and topology were investigated by Fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and scanning electron microscopy (SEM). The addition of PAA into the coagulation bath was revealed to cause the formation of a thicker and denser selective layer with decreasing its pore size and porosity; according to the structural characterization, an interpolymer complex of the two additives was formed on the surface of the PSF membrane. Hydrophilicity of the membrane selective layer surface was shown to increase significantly. The selective layer surface charge was found to become more negative in comparison to the reference membrane. It was shown that PSF/Synperonic F108/PAA membranes are characterized by better antifouling performance in ultrafiltration of humic acid solution and thermomechanical pulp mill (ThMP) process water. Membrane modification with PAA results in higher ThMP process water flux, fouling recovery ratio, and hemicellulose and total lignin rejection compared to the reference PSF/Synperonic F108 membrane. This suggests the possibility of applying the developed membranes for hemicellulose concentration and purification.

Preparation and Characterization of Polyvinylalcohol/Polysulfone Composite Membranes for Enhanced CO2/N2 Separation

“…Based on the FTIR spectra in Figure 4 , it can be found that two strong characteristic peaks were observed at the wavelengths of 1489 and 1586 cm −1 for the pure PSf substrate [ 38 ], which indicates an aromatic vibrational bonding of C=C in the polysulfone group. Moreover, the peaks at the wavenumbers of 1151 and 1242 cm −1 are the vibrational bonding of O=S=O and C–O–C in the ether group.…”

Development of High Flux Nanocomposite Polyphenylsulfone/Oxidized Multiwalled Carbon Nanotubes Membranes for Ultrafiltration Using the Systems with Critical Solution Temperatures

“…The choice of these membranes is attributed to their moderate pure water flux and the surface roughness of the membrane selective layer ( Figure 8 , Figure 10 and Figure 11 a, Table 4 ). It is widely known that antifouling performance in ultrafiltration is determined by the pore size, surface roughness, hydrophilicity and zeta potential of the membrane selective layer [ 70 , 71 , 72 , 73 ].…”

Effect of the Addition of Polyacrylic Acid of Different Molecular Weights to Coagulation Bath on the Structure and Performance of Polysulfone Ultrafiltration Membranes

“…This technique can contribute to surface modification due to the embedding of hydrophilic polymers or polyelectrolytes into the selective layer, which yields changes in the hydrophilicity, roughness, charge and chemical composition of the membranes. This approach was developed and studied in [ 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 ].…”

“…Polyacrylic acid (PAA) [ 48 , 49 , 53 ], polyethylene imine (PEI) [ 37 , 41 , 43 ], copolymers Praestol 859 [ 47 , 51 ] and Praestol 2540 [ 50 ], poly (diallyldimethylammonium chloride) [ 41 ], chitosan [ 55 ], zwitterionic copolymers [ 56 ], poly (sodium 4-styrenesulfonate) (PSS) [ 40 ], PVP [ 52 ] and PVA [ 54 ] were applied as additives to the coagulant for preparation of flat-sheet and hollow fiber membranes. There are different purposes which can be achieved by the addition of hydrophilic polymers and polyelectrolytes to precipitation medium: Increase in membrane antifouling performance [ 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 56 ]; Formation of a separation layer after subsequent cross-linking [ 37 , 38 ] or reaction with oppositely charged polyelectrolyte [ 37 , 40 , 41 , 42 , 45 , 46 ]; Creating an intermediate layer for preparation of the composite membrane via interfacial polymerization (IP) technique [ 44 ]; Tailoring membrane surface charge for enhanced separation of charged molecules [ 39 ]. …”

“…Previously, Burts et al [ 48 , 49 ] and Bildyukevich et al [ 53 ] studied the surface modification of polysulfone (PSF) [ 48 , 49 ] and polyethersulfone (PES) membranes [ 53 ] by addition of PAA with a molecular weight of 250 kDa to the coagulant. It was shown that using PAA aqueous solutions as coagulation bath decreased the coagulation rate due to the rise in precipitation medium viscosity and abatement of the mutual diffusion of solvent and coagulant, which yielded a decrease in the pore size of the membrane selective layer [ 48 , 49 ].…”