Transition sandwich Janus membrane of cellulose acetate and polyurethane nanofibers for oil–water separation

Abstract

Through sequential electrospinning, a sandwich Janus membrane (PU-(CA/PU)-CA) was constructed with hydrophobic polyurethane (PU) nano ber membrane as the top layer, cellulose acetate/polyurethane (CA/PU) blend nano ber membrane as the intermediate transition layer and hydrophilic cellulose acetate (CA) nano ber membrane as the bottom layer. The effects of membrane structure, composition and thickness on the mechanical properties, permeability and separation ability of PU-(CA/PU)-CA nano ber membrane were studied. The results show that the transition sandwich structure PU-(CA/PU)-CA membrane has good mechanical properties, high permeability and selective separation ability, and can realize the unidirectional transmission of water and e cient oil-water separation. When the membrane thickness is 80 μm, the hydraulic permeability is 3.4×10 4 L/(m 2 h bar), the oil-water separation e ciency reaches 99%, and the tensile strength is 95.8% higher than that of the double-layer PU-CA membrane without intermediate transition layer. The thermal stability and antifouling ability of PU-(CA/PU)-CA nano ber membrane have also been improved, and the reusability is good. CA/PU transition interlayer improves the interfacial compatibility between CA and PU nano ber membrane, enhances the performance of PU-(CA/PU)-CA nano ber Janus membrane, and shows its application prospect in the eld of separation and puri cation.

Fabrication and characterization of porous deacetylated cellulose acetate casting membrane with excellent oil/water separation performance

“…While, the membrane separation technique has become attractive to more and more researchers due to its high efficiency, low energy consumption, continuous operation and environment protecting in recent years 13 . There are many types of membranes was used to separation oil/water mixtures, such as electrospinning nanofiber membrane, 14 hydrogel membrane, 15 casting membrane, 16 and so forth. Electrospinning nanofiber membrane has the advantages of high specific surface area, large porosity, good flexibility and interconnectivity, but its production efficiency is low, and most of the organic solvents were used in electrospinning process, which is easy to cause environmental pollution 17–19 .…”

Cellulose acetate superhydrophobic coatings for efficient oil–water separation using a combination of electrostatic spraying and chemical vapor deposition

“…CA can be made into porous membrane material with high selectivity, high water permeability, and simple processing. 16 Due to these characteristics and the hydrophilic of CA, it is often prepared as a nano-fiber membrane or ultrafiltration membrane for the separation of oil and water mixtures, but this is hampered by its poor mechanical strength. In this study, we have designed a simple process to prepare the functional CA coating-loaded SSM through electrostatic spray of CA and followed by chemical vapor deposition 20 of MTCS.…”

“…The separation flux of this membrane can be as high as 38,000 L·m −2 ·h −1 , and the separation efficiency for different oil–water mixtures can be up to 99.97%. Zhang et al 16 prepared PU–(CA–PU)–CA sandwich Janus membranes by sequential electrostatic spinning using hydrophobic polyurethane (PU) and hydrophilic cellulose acetate (CA) as raw materials. When the membrane thickness was 80 μm, the hydraulic permeability was 3.4 ± 0.4 × 10 4 L/(m 2 ·h·bar), the oil–water separation efficiency reached 99 ± 0.4%, and the tensile strength was 95.8% higher than that of the bilayer PU–CA membrane.…”

“…CA was first prepared in 1865 and was the first of the commercially produced cellulose derivatives. CA can be made into porous membrane material with high selectivity, high water permeability, and simple processing 16 . Due to these characteristics and the hydrophilic of CA, it is often prepared as a nano‐fiber membrane or ultrafiltration membrane for the separation of oil and water mixtures, but this is hampered by its poor mechanical strength.…”

Improvement of Antibacterial and Antifouling Properties of a Cellulose Acetate Membrane by Surface Grafting Quaternary Ammonium Salt

“…As a renewable natural polymer, cellulose acetate (CA) has important applications in the fields of bioseparation, desalination, and water treatment because of its rich raw materials, good biocompatibility, low cost, and easy film formation. − However, the hydrophilicity of CA is not strong enough, leading to CA membrane fouling that is still a major challenge . Meanwhile, because CA is a polysaccharide compound connected by dehydrated glucose units, it is easy to be attached, eroded, and degraded by microorganisms such as bacteria in complex water bodies, resulting in a serious decline in flux, retention, and durability .…”