The Effect of Sodium Chloride (NaCl) Coagulant Medium of Polysulfone Ultrafiltration Membrane

Abstract

This study investigates the effect of Sodium Chloride (NaCl) coagulant medium with different concentration to produce Polysulfone (PSf) ultrafiltration (UF) asymmetric membrane. The polymer membrane prepared by a phase inversion method using Polysulfone (PSf) as a base polymer, Polyethylene glycol (PEG) 400MW as copolymer additive, N-methyl-2-pyrrolidone (NMP) as solvent and NaCl coagulant medium with different concentration as nonsolvent. In this work, the concentration of immersion medium for membrane phase immersion process prepared based on different coagulation concentration medium NaCl was modified repeatedly in the range of 1-5%. These membrane performance were analyzed via pure water permeation and solute rejection of humic acid. Based on these results, the membrane immersed in 4% concentration of NaCl coagulant medium showed the highest pure water permeation (235.69 l.m -². h -¹) and solute rejection of humic acid which is up to 98%. IntroductionPhase inversion is one of the most popular and common technique that used for most researchers via immersion precipitation as a way to prepare microfiltration and ultrafiltration asymmetric membrane of polymer [1][2][3][4][5] and ceramic membranes [6][7][8]. According to this technique, a thin film of polymer homogenous dope solution is cast on a suitable substrate such as glass, polyester or polyethylene non-woven fabric, metal, Teflon henceforward immersed in a non-solvent bath where exchange between solvent and non-solvent and the precipitation of polymer take place [7].Nevertheless, this conventional method is not flexible enough to produce all the ideal membrane structure and properties. Thus, modification of basic procedure are commonly required including the addition of certain additive [1][2][3][4][5], introducing advance stride to make enhancement such as evaporation [9] or annealing [10], and coupling chemical reaction with phase separation [11]. Previous studies reported that by modification of polysulfone (PSf) ultrafiltration membrane with changing composition in casting solution or coagulation bath will gives positive implication to morphology and properties of membrane [12,13]. Coagulation bath is one of the methods used to make modification of membrane in term of structure and properties with an addition certain additive such as inorganic salt.

Effect of Zinc Oxide on Performance of Ultrafiltration Membrane for Humic Acid Separation

“…Dope solution was cast on the glass plate with casting knife gap setting at 150 µm at an appropriate casting shear 10,11 . The cast solution was then immersed in water bath until the membrane thin film peels off naturally.…”

“…However the major disadvantage of PSf is hydrophobic characteristic which is easy for pollutant to adsorb on membrane surface and cause serious fouling behaviour. Thus the current investigation to improve PSf surface have been progressively studied such as using low molecular weight hydrophilic polymer, inorganic additives and chemical modification such as grafting and crosslinking [6][7][8][9][10][11][12][13] . Blending inorganic additives such as titanium dioxide (TiO2), Silica (SiO2), zinc oxide (ZnO) and silver oxide in PSf membrane was found to improve hydrophilicity and reduce fouling properties of membrane.…”

Influence of Inorganic Additives on the Performance of Polysulfone Ultrafiltration Membrane

“…Flat sheet membranes were prepared by casting a polymer solution (18 wt % of PSf) with different additives contents on a glass plate. Dope solution was cast on the glass plate with casting knife gap setting at 150 µm at an appropriate casting shear 15,16 . The cast solution was then immersed in water bath until the membrane thin film peeled off naturally.…”

Membrane Performance: TiO2 Nanoparticles Coated on Polysulfone (PSf) Ultrafiltration Membrane Surfaces

“…Polysulfone membrane was prepared using phase inversion method. The casting solution was cast using casting knife with range thickness 100-120μm and immersed into a coagulation bath containing distilled water as a non-solvent [8][9][10] . The TiO2 coated membrane was prepared by dipping (PTL-MM01 Dip Coater) the prepared polysulfone membrane in different concentrations of TiO2 nanoparticles (0.01, 0.03 and 0.05 wt.%) with speed 50 mm/second.…”