Acetone/Water Separation through Polydimethylsiloxane/PEBAX/Titania Nanocomposite Membrane by Pervaporation Method

The need to separate acetone from waste water of industrial units such as dyeing, ink production, glazing, etc. has encouraged researchers to propose various separation methods for this purpose. Among different separation techniques, the pervaporation has been considered as a promising one due to its low energy consumption, operational simplicity and environmental compatibility. In this paper, the removal of acetone from water solution using the prepared polydimethylsiloxane/PEBAX/titania nanocomposite membrane by the pervaporation method has been investigated. After the fabrication of the membranes, they were characterized by various analyses including scanning electron microscopy, Fourier-transform infrared spectroscopy, X-ray diffraction, thermal gravimetric analysis, and contact angle to study morphology, chemical bonds changes, crystalline structure, thermal resistance, and hydrophobicity feature of the resultant membranes, respectively. Designing the experiments by Taguchi technique, the effect of three variables: feed concentration (4, 8 and 12 wt.%), titania nanoparticles content (0.0, 0.75 and 1.5 wt.%), and operating temperature (27, 37 and 47 °C) on the separation efficiency of acetone from water was surveyed. The characterization membranes’ results are indicative of a proper distribution of the nanoparticles in the membranes matrices, dense structure of the membranes, the existence of expected functional groups in the membranes, as well as the increased hydrophobicity of the membranes. The FTIR outcomes confirm the presence of PEBAX, polydimethylsiloxane, along with the titania nanoparticles in the fabricated membranes. Besides, the semi-crystalline structure of the membranes which is affirmed by the XRD analysis exhibits the existed crystalline and amorphous parts in their bodies. The SEM photos displays PEBAX-based selective layer with its defect free and dense structure, along with the polydimethylsiloxane-based support layer containing the titania nanoparticles. The obtained results of this study indicated that with raising the titania nanoparticles loading, the separation efficiency of acetone from the water solution firstly increased due to the improved hydrophobicity of the membranes resulting from the well-dispersed titania nanoparticles and then decreased because of the aggregated nanofillers. Moreover, the results exhibited that there is a direct relation between the acetone concentration in feed and the acetone separation efficiency. It was also shown that the as the operating temperature is enhanced from 27 to 37 °C, the separation efficiency increases remarkably, while it does not change significantly at the temperature more than 37 °C. The pervaporation experiments revealed the maximum acetone/water separation efficiency of 90.11% for the membrane embedded with 0.75 wt. % of the titania nanoparticles at 37 °C and 12 wt. % of feed concentration.