Modified Silica Incorporating into PDMS Polymeric Membranes for Bioethanol Selection

Abstract

In this work, polydimethylsiloxane (PDMS) polymeric membranes were fabricated by incorporating fumed silica nanoparticles which were functionalized with two silane coupling agents—NH2(CH2)3Si(OC2H5)3(APTS) and NH2(CH2)2NH(CH2)3Si(OC2H5)3(TSED)—for selective removal of ethanol from aqueous solutions via pervaporation. It was demonstrated that large agglomerates were not observed indicating the uniform distribution of modified silica throughout the PDMS matrices. It is noted that the ethanol diffusivity and the water contact angles were both increased remarkably, being beneficial to the preferential permeation of ethanol through the membranes. The pervaporation results showed that the addition of the two types of modified silica nanoparticles dramatically enhanced both the permeability and selectivity of hybrid membranes. Compared to APTS, silica modified by TSED at the concentration of 4 wt. % resulted in the optimum pervaporation membranes with the maximum separation factor of 12.09 and the corresponding permeation flux of approximately 234.0 g·m−2·h−1in a binary aqueous mixture at 40°C containing 10 wt. % ethanol. The observation will benefit the choice of coupling agents to improve the compatibility between hydrophilic fillers and hydrophobic polymers in preparing mixed matrix membranes.

Fabrication and Characterization of Carbon Nanotube Filled PDMS Hybrid Membranes for Enhanced Ethanol Recovery

“…Recently, much research work has been devoted to improving the separation performance of PDMS membrane though cross-linking, grafting, copolymerization, mixing with porous filler, etc. − Among them, mixed matrix membranes (MMMs), prepared by combining micro- or nanoparticles with a polymer matrix, have been recognized as one of the most promising technology to prepare membranes with outstanding separation performance. On the one hand, micro- or nanoparticles are resistant to harsh chemical environment and have good rigidity and high thermal stability, which make the membrane have long-term stability .…”

Nanostructured Polymethylsiloxane/Fumed Silica Blends

“…Silicas can easily be modified to significantly change many important characteristics of the materials [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16]. Various functionalized silicas (fumed nanosilica, silica gels, precipitated silicas, ordered mesoporous silicas, etc.)…”

“…Various functionalized silicas (fumed nanosilica, silica gels, precipitated silicas, ordered mesoporous silicas, etc.) and siloxane-based polymers (e.g., linear polydimethylsiloxane, PDMS, 3D-cross-linked polymethylsiloxane (PMS)) are widely used in industry and medicine as well in various branches of science [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23]. One of the main characteristics of these materials is their degree of hydrophobicity, which allows their interactions with various liquids, polymers, and solids to be controlled.…”

Nanostructured Amorphous Silicas Hydrophobized by Various Pathways

“…14−25 Clearly, these aspects are of importance because the hydrophobization of NAS influences not only the structure of a solid surface but also other characteristics and properties of the materials. 1−13,26−29 Different modifiers with low-molecular weight (MW) can be applied for the hydrophobization of NAS, such as organosilanes [(CH 3 O) x SiR 4– x ], chlorosilanes (Cl x SiR 4– x , where R = CH 3 or other organic functional groups), and hexamethyldisilazane (HMDS). 29−35…”

“…Hydrophobized NAS are of interest from a practical point of view because these materials are better fillers of nonpolar or weakly polar polymers as well as being more appropriate for other practical applications than hydrophilic NAS. ,− Therefore, a deeper insight into the problem of hydrophobization of various NAS by various modifiers is of importance. The morphological, textural, and structural features of various NAS can strongly affect the results of hydrophobization: the degree of hydrophobization (θ), possible length of hydrophobic functionalities, and changes in the porosity and S BET , and so forth. − Clearly, these aspects are of importance because the hydrophobization of NAS influences not only the structure of a solid surface but also other characteristics and properties of the materials. − ,− Different modifiers with low-molecular weight (MW) can be applied for the hydrophobization of NAS, such as organosilanes [(CH 3 O) x SiR 4– x ], chlorosilanes (Cl x SiR 4– x , where R = CH 3 or other organic functional groups), and hexamethyldisilazane (HMDS). − …”