Deduction of Surfactants Effect on Performance, Morphology, Thermal and Molecular Properties of Polymeric Polyvinylidene Fluoride (PVDF) Based Ultrafiltration Membrane

Abstract

In membrane making, surfactant material is one of the effective strategies to produce membrane / thin film with optimal and specific properties. This paper addressed the effect of Sodium dodecyl sulphate (SDS), Triton X-100 and Tween 80 as additives for the making of Polyvinylidene fluoride (PVDF) ultrafiltration (UF) membranes. The fabricated membranes were analysed in the aspect of performance, morphological structures, thermal properties and molecular orientation. Analysis results showed that the surfactant additives enhanced the membrane performance and properties. Surprisingly, the addition of 2 wt% surfactant increased the permeate flux of bovine serum albumin (BSA) up to 78.14 L/m2h compared to membrane without surfactant with flux at only 2.74 L/m2h. In addition, the role of surfactants on membrane pores and pore properties of PVDF UF membranes were examined. The cross-sectional morphological structures showed that these surfactants led towards the formation of macro-voids and finger-like structures as well as a spongy layer. The surfactants additives also improved the membrane pores and pore properties which reflect to the protein rejection up to 85 % and 78 % of BSA and egg albumin (EA), respectively. Moreover, analysis on the thermal features found that SDS, Triton X-100 and Tween 80 promoted better thermal stability and significantly fine molecular alignment which provided the versatility for the membrane to be used for any applications.

Characterization on Performance, Morphologies and Molecular Properties of Dual-Surfactants Based Polyvinylidene Fluoride Ultrafiltration Membranes

“…The produced porous membrane structures can either symmetric (isotropic) or asymmetric (anisotropic) membrane as reported by Ladewig and Al-Shaeli [11] and Gallucci et al [15]. The asymmetric membrane consists of a thin layer (skin) and porous substrate layer whereby the skin layer plays an important part as a selective barrier layer and provides major resistance to the feed solution [12,16]. The polymer solutions undergo solidification proses after being immersed in a water bath (liquid-liquid de-mixing) [17].…”

“…Bovine serum albumin (BSA, Mw = 69 kDa) and egg albumin (EA, Mw = 45 kDa) obtained from Acros Organics, USA were used as the solute for ultrafiltration test. Disodium hydrogen phosphate (Na 2 HPO 4 ) and sodium phosphate monobasic monohydrate (NaH 2 PO 4 .H 2 O) were used as a buffer solution to prepare the protein feed samples and the preparation is referred as in the previous article [12].…”

“…The samples coated with gold, using Auto Fine Coater (JFC-1600) to enhance electronic conductivity. The details of morphological structures (pore lengths and widths) are the average values that measured from 15 measuring points based on the SEM images during the SEM analysis [12,31].…”

“…Even though many studies have been done on the use of surfactants in the research work, there is no article reporting the effects of dual surfactants (combination of surfactants) on the performance, morphologies and properties of polymeric membrane. Besides, the effect of single surfactant in the PVDF membranes was discussed previously in [12].…”

“…In general, membranes can be classified based on their morphologies including dense homogenous polymer membranes, porous membranes and thin-film composite membranes [11]. The polymeric porous membranes for UF, nanofiltration (NF) and reverse osmosis (RO) commonly fabricated via phase inversion technique [12][13][14]. The produced porous membrane structures can either symmetric (isotropic) or asymmetric (anisotropic) membrane as reported by Ladewig and Al-Shaeli [11] and Gallucci et al [15].…”