Influence of sodium bromide additive on polyethersulfone ultrafiltration membranes

Abstract

The effect of sodium bromide (NaBr) on performance and characteristics of ultrafiltration (UF) membranes was studied. Asymmetric UF membranes were prepared by phase inversion technique from a multicomponent dope polymer solution consisting of the polymer; polyethersulfone (PES), solvent; N, N‐dimethylformamide (DMF) and NaBr as micromolecular additive. The dissolution of PES‐DMF‐NaBr was carried out using microwave irradiation technique to induce rapid dissolution through minimal heating time. Various concentrations of NaBr were mixed with PES in the range of 1–5 wt % and its influence on membrane characteristics such as surface hydrophilicity was measured by contact angle and the performance in terms of water flux and rejection rates were evaluated using micromolecular test substances. The morphology and streaming potential of PES UF membranes were analyzed using scanning electron microscopy (SEM) and ζ‐potential measurement, respectively. Overall, the results suggest that the membrane consisting of 1 wt % NaBr exhibits the best performance in terms of rejection and flux rates with molecular weight cutoff (MWCO) of 45 kDa and mean pore size of 6 nm. The membrane with the 1 wt % addition of NaBr demonstrates most negative charge which indicates less fouling characteristics and displays approximately three times higher permeation. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Effect of non-solvent additives on the morphology, pore structure, and direct contact membrane distillation performance of PVDF-CTFE hydrophobic membranes

“…Although some large pores were observed in the membrane surface, the pore interconnectivity of membrane I5 was low, while the pore interconnectivity of I1 to I4 was high. It is believed that the cation in metal salt additives undergoes reaction with the solvent and polymer, which will have an effect on the phase inversion process (Jungbaurer and Curran, 1964;Noor et al, 2013). The viscosity of the membrane will be increased significantly, influencing the phase inversion process.…”

“…Lithium halides like LiCl, LiBr, and LiF have been researched widely, as well as other lithium salts such as LiClO 4 and LiNO 3 , due to the formation of acid-base complexes between the LiCl and solvent and the interaction between Li + ions and electron donor groups of PVDF, which may dramatically affect the phase inversion process during coagulation (Idris et al, 2010;Kurdi and Tremblay, 2001;Wang et al, 2000;Yeow et al, 2005). Other metal salts and inorganic acids such as ZnCl 2 , CaCl 2 , AlCl 3 , NaBr, KClO 4 , Mg(ClO 4 ) 2 , NaNO 3 , and H 3 PO 4 have also been evaluated, and due to the strong interaction among additives, solvent, non-solvent, and polymers, these additives have significant effects on the membrane preparation process and the resultant membranes (Kraus et al, 1979;Kurdi and Tremblay, 2001;Mansourizadeh and Ismail, 2011;Noor et al, 2013;Shinde et al, 1999;Yang and Liu, 2003). H 2 O is another commonly used additive with a slight addition in the casting solution.…”

Preparation and characterization of thermally stable copoly(phthalazinone biphenyl ether sulfone) hollow fiber ultrafiltration membranes

“…Various polymer materials have been used for UF membrane preparation, such as cellulose acetate (CA) [5], polysufone (PSf) [6], polyethersulfone (PES) [7,8] and poly(vinylidene fluoride) (PVDF) [9]. Nevertheless, most commercially available polymeric ultrafiltration membranes could hardly be resistant to high temperature above 80 • C. It has sparked great interest in developing temperature-resistant membranes to be used for dealing with hot streams such as textile bleaching effluents, dyeing industry wastewater free of strict temperature control [10,11].…”