Abstract
In this work, a poly(1-trimethylsilyl-1-propyne) (PTMSP) mixed-matrix membrane was fabricated for the selective removal of 1-butanol from aqueous solutions through pervaporation. Silica nanoparticles (SNPs), which were surface-modified with surfactant hexadecyltrimethylammonium bromide (CTAB), were incorporated into the structure of the membrane. The modified membrane was characterized by thermogravimetry-differential scanning calorimetry (TG-DSC), contact angle measurements, and scanning electron microscope (SEM) analysis. It was found that the surface hydrophobicity of the membrane was improved when compared to neat PTMSP by contact angle measurement. It was confirmed by SEM analysis that a uniform distribution of surface-modified SNPs throughout the PTMSP membrane was achieved. The thermogravimetric analysis detected the thermal degradation of the modified PTMSP at 370 °C, which is comparable to neat PTMSP. The pervaporation measurements showed a maximum separation factor of 126 at 63 °C for 1.5 w/w% 1-butanol in the feed. The maximum total flux of approximately 1.74 mg·cm−2·min−1 was observed with the highest inspected temperature of 63 °C and at the 1-butanol concentration in the feed 4.5 w/w%. The pervaporation transients showed that the addition of the surface-modified SNPs significantly enhanced the diffusivity of 1-butanol in the composite compared to the neat PTMSP membrane. This improvement was attributed to the influence of the well-dispersed SNPs in the PTMSP matrix, which introduced an additional path for diffusivity.
Highlights
Butanol is an ecological and practically non-toxic solvent and an important chemical feedstock, which has been extensively used in many industries [1]
The new hybrid PTMSP membrane had the thickness of 48 ± 2 μm
Silica nanoparticles (SNPs) into membrane resulted in the formation of aggregates that may perhaps cause large of more SNPs into membrane resulted in the formation of aggregates that may perhaps cause large clusters in the top layer, and it had a high chance for defects in membranes
Summary
Butanol is an ecological and practically non-toxic solvent and an important chemical feedstock, which has been extensively used in many industries [1]. PTMSP has already been studied for the liquid separation process for the removal of ethanol, butanol, acetone, etc., from their aqueous solutions by means of pervaporation [9,12]. Claes et al [23] showed that the addition of 25 wt.% hydrophobic silica into the PTMSP matrix and with a PTMSP separating layer of 2.4 μm thickness, clearly increased the permeate flux. This was at the expense of the alcohol/water selectivity. We used a neat PTMSP membrane to study transient and steady-state pervaporation to remove 1-butanol from an aqueous mixture. A comparison between the neat membrane (data from previously published work) and the new hybrid PTMSP membrane was conducted
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