Effects of Water as Non-Solvent Additive on Performance of Polysulfone Ultrafiltration Membrane

Abstract

Abstract. In this work, polysulfone ultrafiltration membranes were prepared via simple phase inversion with distilled water as non-solvent additive. The main reason for the addition of water in polysulfone dope solution preparation was to enhance the membranes structure. In the dope, 15 wt. % of polysulfone was used and water was varied up to 6 wt. %. The effects of water on morphology, porosity and tensile properties were investigated in detail. From the porosity test, results showed that the addition of water has improved membrane porosity up to 53 %. The FESEM images revealed that membrane morphology has also been modified. However, the tensile properties of membrane decreased as water content increased which may be due to the porosity interaction between polysulfone/NMP with water.

Performance Studies of Polysulfone-Based Membrane: Effect of Silica Morphology

“…This straight or longer finger-like structure formed at the bottom give better permeation compared to short finger-like structure [7]. In fact, by increasing the RHS content, the pore at the top layer membrane become smaller.…”

“…The addition of small amount of additive into casting solution can lead to significant changes to the characteristic and performance of membrane [4,5,6]. It is reported that additives can affect the final membrane characteristic either by changing the solvent capacity or by changing phase separation kinetic and thermodynamic mechanism [7,8]. The additive have tendency to enlarge macrovoids formation which then improve the interconnectivity of the pores and resulting in higher porosities in the top layer and sub layer [9].…”

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

“…Later on, The casting solution was cast using casting knife with range thickness 100-120µm and immersed into a coagulation bath containing distilled water. Then, the flat sheet membranes were dried 24 h before testing [1,2,3,11]. In this study, the coagulation medium were demineralized water or aqueous solution of sodium chloride (NaCl) at dissimilar concentrations is modified repeatedly in the range of 1-5 %.…”

“…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].…”

“…Phase 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].…”