One-Step and Low-Cost Designing of Two-Layered Active-Layer Superhydrophobic Silicalite-1/PDMS Membrane for Simultaneously Achieving Superior Bioethanol Pervaporation and Fouling/Biofouling Resistance

Abstract

Recently, the coupling of biofuel fermentation broths and pervaporation has been receiving increasing attention. Some challenges, such as the destructive effects of constituents of the real fermentation broth on the membrane performances, the lethal effects of the membrane surface chemical modifiers on the microorganisms, and being expensive, are against this concept. For the first time, a continuous study on the one-step and low-cost preparation of superhydrophobic membranes for bioethanol separation is made to address these challenges. In our previous work, spraying as a fast, scalable, and low-cost procedure was applied to fabricate the one-layered active-layer hydrophobic (OALH) silicalite-1/polydimethylsiloxane (PDMS) membrane on the low-cost mullite support. In this work, the spraying method was adopted to fabricate a two-layered active-layer superhydrophobic (TALS) silicalite-1/PDMS membrane, where the novel active layer consisted of two layers with different hydrophobicities and densities. Contact-angle measurements, surface charge determination, scanning electron microscopy, atomic force microscopy, and pervaporation separation using a 5 wt % ethanol solution were used to statically evaluate the fouling/biofouling resistance and pervaporation performances of OALH and TALS membranes in this study. The TALS membrane presented a better resistance and performance. For dynamic experiments, the Box− Behnken design was used to identify the effects of substrates, microorganisms, and nutrient contents as the leading indicators of fermentation broth on the TALS membrane performances for the long-term utilization. The maximum performances of 1.88 kg/m 2 • h, 32.34, and 59.04 kg/m 2 •h concerning the permeation flux, separation factor, and pervaporation separation index were obtained, respectively. The dynamic fouling/biofouling resistance of the TALS membrane was also characterized using energy-dispersive X-ray spectroscopy of all the tested membranes. The TALS membrane demonstrated the synergistic resistance of membrane fouling and biofouling. Eventually, the novel TALS membrane was found to have potential for biofuel recovery, especially bioethanol.

Thin-Film Composite (TFC) Polydimethylsiloxane (PDMS) Membrane with High Crosslinking Density Fabricated by Coaxial Electrospray for a High Flux

“…where v d is the number of moles of the elastic network chains in 1 cm 3 , ρ is the density of the PDMS membrane, and M c is the mass of the PDMS sample containing 1 mol elastic molecular chains. 2.6.…”

“…Polydimethylsiloxane (PDMS) is a widely used polymer material for membrane fabrication, since it is easily fabricated, is chemically stable, and has a great affinity with organics as well as high hydrophobicity. − The PDMS membrane can be applied for organic solvent recovery, , VOC removal, , and gas separation. , Besides, it has been reported that higher productivity and lower energy required can be achieved, if pervaporation separation by the PDMS membrane is coupled with ethanol fermentation for bioethanol in situ removal from the broth to eliminate ethanol inhibition. , In conventional methods for PDMS membrane fabrication, membrane thickness vs defects, or membrane flux vs selectivity, is always an irritating trade-off problem. − Thus, optimizing the membrane thickness while limiting membrane defects to boost the separation performance is of great importance for developing PDMS membranes. In order to achieve this objective, the thin-film composite (TFC) membrane has been considered an alternative with a thinner thickness to get a higher membrane flux …”

A fabric-based superhydrophobic ACNTs/Cu/PDMS heater with an excellent electrothermal effect and deicing performance

“…24 Introducing superhydrophobicity into conductive fabrics is one of the effective ways to solve obstacles to their application. 5,25 A superhydrophobic surface usually refers to a material or object surface, which can make the water droplets falling on it present a surface with a water contact angle (WCA) 4 1501 and a sliding angle (SA) o 51. [26][27][28] Such materials are inspired by nature, such as lotus leaves, the feet of water striders, 29,30 butterfly wings, 31 taro leaves, 32 rose petals, 33,34 and so on.…”

Enhanced n‐butanol permselective vapor permeation by incorporating ZIF‐8 into a polydimethylsiloxane composite membrane: Effect of filler loading contents

“…[8] Although hydrophobic non-porous polymeric membranes, such as polydimethylsiloxane (PDMS), et al, have excellent biobutanol/ water separation performance, it is still suffering from limited perm-selectivity. [9] In recent years, the incorporation of porous nanofiller with alcohol affinities such as silicalite-1, [10] ZSM-5 zeolite, [11] silica, [12] and metal-organic frameworks (MOFs) [13,14] into a polymer-based membrane has been considered as a promising strategy to address this issue.…”