scholarly journals Chemically Cross-Linked Graphene Oxide as a Selective Layer on Electrospun Polyvinyl Alcohol Nanofiber Membrane for Nanofiltration Application

Nanomaterials ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 2867
Author(s):  
Myoung Jun Park ◽  
Grace M. Nisola ◽  
Dong Han Seo ◽  
Chen Wang ◽  
Sherub Phuntsho ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Polyvinyl Alcohol ◽  
Self Assembly ◽  
Water Flux ◽  
Composite Membranes ◽  
Cross Linking ◽  
Support Surface ◽  
Eosin Y ◽  
Selective Layer ◽  
Assembly Technique

Graphene oxide (GO) nanosheets were utilized as a selective layer on a highly porous polyvinyl alcohol (PVA) nanofiber support via a pressure-assisted self-assembly technique to synthesize composite nanofiltration membranes. The GO layer was rendered stable by cross-linking the nanosheets (GO-to-GO) and by linking them onto the support surface (GO-to-PVA) using glutaraldehyde (GA). The amounts of GO and GA deposited on the PVA substrate were varied to determine the optimum nanofiltration membrane both in terms of water flux and salt rejection performances. The successful GA cross-linking of GO interlayers and GO-PVA via acetalization was confirmed by FTIR and XPS analyses, which corroborated with other characterization results from contact angle and zeta potential measurements. Morphologies of the most effective membrane (CGOPVA-50) featured a defect-free GA cross-linked GO layer with a thickness of ~67 nm. The best solute rejections of the CGOPVA-50 membrane were 91.01% for Na2SO4 (20 mM), 98.12% for Eosin Y (10 mg/L), 76.92% for Methylene blue (10 mg/L), and 49.62% for NaCl (20 mM). These findings may provide one of the promising approaches in synthesizing mechanically stable GO-based thin-film composite membranes that are effective for solute separation via nanofiltration.

scholarly journals Cross-Linking With Diamine Monomers to Prepare Graphene Oxide Composite Membranes With Varying D-Spacing for Enhanced Desalination Properties

2021 ◽  
Vol 9 ◽  
Author(s):  
Hong Ju ◽  
Jinzhuo Duan ◽  
Haitong Lu ◽  
Weihui Xu
Keyword(s):  
Graphene Oxide ◽  
Photoelectron Spectroscopy ◽  
Water Flux ◽  
Covalent Bond ◽  
Composite Membranes ◽  
Rejection Rate ◽  
High Water ◽  
Cross Linking ◽  
Separation Performance ◽  
X Ray

As a new type of membrane material, graphene oxide (GO) can easily form sub-nanometer interlayer channels, which can effectively screen salt ions. The composite membrane and structure with a high water flux and good ion rejection rate were compared by the cross-linking of GO with three different diamine monomers: ethylenediamine (EDA), urea (UR), and p-phenylenediamine (PPD). X-ray photoelectron spectroscopy (XPS) results showed that unmodified GO mainly comprises π-π interactions and hydrogen bonds, but after crosslinking with diamine, both GO and mixed cellulose (MCE) membranes are chemically bonded to the diamine. The GO-UR/MCE membrane achieved a water flux similar to the original GO membrane, while the water flux of GO-PPD/MCE and GO-EDA/MCE dropped. X-ray diffraction results demonstrated that the covalent bond between GO and diamine can effectively inhibit the extension of d-spacing during the transition between dry and wet states. The separation performance of the GO-UR/MCE membrane was the best. GO-PPD/MCE had the largest contact angle and the worst hydrophilicity, but its water flux was still greater than GO-EDA/MCE. This result indicated that the introduction of different functional groups during the diamine monomer cross-linking of GO caused some changes in the performance structure of the membrane.

Effect of Microstructure of Graphene Oxide Fabricated Composite Membranes on Alcohol Dehydration

2014 ◽  
Vol 1051 ◽  
pp. 278-282 ◽  
Author(s):  
Wei Song Hung ◽  
Kueir Rarn Lee ◽  
Juin Yih Lai
Keyword(s):  
Graphene Oxide ◽  
Self Assembly ◽  
Driving Forces ◽  
Composite Membranes ◽  
The Self ◽  
Separation Performance ◽  
Permeation Flux ◽  
Laminate Structure ◽  
Alcohol Dehydration ◽  
Assembly Technique

We utilized pressure-, vacuum-, and evaporation-assisted self-assembly techniques through which graphene oxide (GO) was deposited on modified polyacrylonitrile (mPAN). The fabricated composite GO/mPAN membranes were applied to dehydrate 1-butanol mixtures by pervaporation. Varying driving forces in the self-assembly techniques induced different GO assembly layer microstructures. XRD results indicated that the GO layer d-spacing varied from 8.3 Å to 11.5 Å. The self-assembly technique with evaporation resulted in a heterogeneous GO layer with loop structures; this layer was shown to be hydrophobic, in contrast to the hydrophilic layer formed from the other two techniques. From the pressure-assisted technique, the composite membrane exhibited exceptional pervaporation performance at 30 °C: concentration of water at the permeate side = 99.6 wt% and permeation flux = 2.54 kg m-2 h-1. This excellent separation performance stemmed from the dense, highly ordered laminate structure of GO.

Pressure-assisted self-assembly technique for fabricating composite membranes consisting of highly ordered selective laminate layers of amphiphilic graphene oxide

Carbon ◽  
2014 ◽  
Vol 68 ◽  
pp. 670-677 ◽  
Author(s):  
Wei-Song Hung ◽  
Quan-Fu An ◽  
Manuel De Guzman ◽  
Hsin-Yi Lin ◽  
Shu-Hsien Huang ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Self Assembly ◽  
Composite Membranes ◽  
Assembly Technique

Multilayer composite beads constructed via layer-by-layer self-assembly for lysozyme controlled release

RSC Advances ◽  
2014 ◽  
Vol 4 (46) ◽  
pp. 24369-24376 ◽  
Author(s):  
Jiemin Zhao ◽  
Xiaoping Wang ◽  
Yanshen Kuang ◽  
Yufeng Zhang ◽  
Xiaowen Shi ◽  
...  
Keyword(s):  
Controlled Release ◽  
Self Assembly ◽  
Cross Linking ◽  
Layer By Layer ◽  
Multilayer Composite ◽  
Composite Beads ◽  
Assembly Technique ◽  
Positively Charged

Alginate (ALG)–lysozyme (LZ) beads were fabricated by a cross-linking process. Negatively charged ALG and positively charged LZ were alternately deposited on the positively charged ALG–LZ beads via a layer-by-layer (LBL) self-assembly technique.

scholarly journals Biofouling Characteristics of Graphene Oxide Membrane in a Protein-rich Environment

2021 ◽  
Author(s):  
Richard P Rode ◽  
Saeed Moghaddam
Keyword(s):  
Graphene Oxide ◽  
Self Assembly ◽  
Membrane Surface ◽  
Water Flux ◽  
Polymer Membrane ◽  
Blood Protein ◽  
Separation Processes ◽  
Sem Images ◽  
Membrane Flux ◽  
Protein Rich

Membrane biofouling has inhibited permselective separation processes for decades, requiring frequent membrane backwash treatment or replacement to maintain efficacy. However, frequent treatment is not viable for devices with a continuous blood flow such as a wearable or implantable dialyzer. In this study, the biofouling characteristics of a highly hemocompatible graphene oxide (GO) membrane developed through a novel self-assembly process is studied in a protein-rich environment and compared with performance of a state-of-the-art commercial polymer membrane dialyzer. The studies are conducted in phosphate-buffered saline (PBS) environment using human serum albumin (HSA), which represents 60% of the blood protein, at the nominal blood protein concentration of 1 g L-1. Protein aggregation on the membrane surface is evaluated by monitoring the change in the membrane flux and SEM imaging. The GO membrane water flux declined only ~10% over a week-long test whereas the polymer membrane flux declined by 50% during the same period. The SEM images show that HSA primarily aggerates over the graphitic regions of nanoplatelets, away from the charged hydrophilic edges. This phenomenon leaves the open areas of the membrane formed between the nanoplatelets edges, through which the species pass, relatively intact. In contrast, HSA completely plugs the polymer membrane pores resulting in a steady decline in membrane permeability.

Preparation of Stable Hydrophilic Polyethyleneimine Cross-Linked Graphene Oxide/Titanium Dioxide Membranes for Dye Separation

NANO ◽  
2021 ◽  
pp. 2150008
Author(s):  
Hongwei Liu ◽  
Jinhua Liu ◽  
Jun Li ◽  
Zhanchao Liu ◽  
Weifu Wu ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Titanium Dioxide ◽  
Graphene Oxide ◽  
Water Flux ◽  
Cross Linking ◽  
Sunset Yellow ◽  
Water Contact ◽  
Static Water ◽  
The Cross ◽  
The Stability

An excellent novel laminar and hierarchical polyethyleneimine cross-linked graphene oxide/titanium dioxide (GO–TiO2–PEI) membrane was successfully prepared by vacuum filtration technology using polyethyleneimine (PEI) as the cross-linking agent and a GO–TiO2 nanocomposite as the substrate. The resultant membrane (GO–TiO2–PEI) displayed a favorable antifouling performance with bovine serum albumin (BSA) and showed good hydrophilicity and wettability, with a static water contact angle of 13.2∘. The stability of the GO–TiO2–PEI membrane in aqueous solution obviously improved with the cross-linking of PEI compared with that of the GO and GO–TiO2 membranes. The GO–TiO2–PEI membrane also exhibited a satisfactory water flux of 48.6[Formula: see text]L m[Formula: see text] h[Formula: see text] bar[Formula: see text]. The GO–TiO2–PEI membrane exhibited a good performance for effectively separating different dyes including methylene blue (MB), rhodamine B (RB), methyl orange (MO), sunset yellow (SY), new coccine (NC) and amaranth. All the above results suggested that the GO–TiO2–PEI membrane could be used as an excellent stable hydrophilic membrane for efficiently separating dyes from aqueous solution.

Non-covalent modification of graphene oxide nanocomposites with chitosan/dextran and its application in drug delivery

RSC Advances ◽  
2016 ◽  
Vol 6 (11) ◽  
pp. 9328-9337 ◽  
Author(s):  
Meng Xie ◽  
Hailin Lei ◽  
Yufeng Zhang ◽  
Yuanguo Xu ◽  
Song Shen ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Graphene Oxide ◽  
Self Assembly ◽  
Covalent Modification ◽  
Cancer Drug ◽  
Graphene Oxide Nanosheets ◽  
Drug Delivery Application ◽  
Anti Cancer ◽  
Assembly Technique ◽  
Cancer Drug Delivery

Graphene oxide nanosheets non-covalent functionalized with chitosan/dextran was successfully developed via LbL self-assembly technique for anti-cancer drug delivery application.

Reduction versus cross-linking: how to improve the tensile strength of graphene oxide/polyvinyl alcohol composite film

2017 ◽  
Vol 4 (8) ◽  
pp. 085601 ◽  
Author(s):  
Cheng-an Tao ◽  
Hao Zhang ◽  
Jian Huang ◽  
Xiaorong Zou ◽  
Hui Zhu ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Graphene Oxide ◽  
Polyvinyl Alcohol ◽  
Composite Film ◽  
Cross Linking

scholarly journals Amino Acid Cross-Linked Graphene Oxide Membranes for Metal Ions Permeation, Insertion and Antibacterial Properties

Membranes ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 296 ◽  
Author(s):  
Lijuan Qian ◽  
Haijing Wang ◽  
Jingyi Yang ◽  
Xiaolei Chen ◽  
Xue Chang ◽  
...  
Keyword(s):  
Amino Acids ◽  
Graphene Oxide ◽  
Metal Ions ◽  
Water Flux ◽  
Antibacterial Properties ◽  
Earth Metal ◽  
Composite Membranes ◽  
Interlayer Spacing ◽  
Nylon Membrane ◽  
Alkaline Earth Metal Ions

Graphene oxide (GO) and its composite membranes have exhibited great potential for application in water purification and desalination. This article reports that a novel graphene oxide membrane (GOM) of ~5 µm thickness was fabricated onto a nylon membrane by vacuum filtration and cross-linked by amino acids (L-alanine, L-phenylalanine, and serine). The GOM cross-linked by amino acids (GOM-A) exhibits excellent stability, high water flux, and high rejection to metal ions. The rejection coefficients to alkali and alkaline earth metal ions through GOM-A were over 94% and 96%, respectively. The rejection coefficients decreased with an increasing H+ concentration. Metal ions (K+, Ca2+, and Fe3+) can be inserted into GOM-A layers, which enlarges the interlayer spacing of GOM-A and neutralizes the electronegativity of the membrane, resulting in the decease in the rejection coefficients to metal ions. Meanwhile, GOM-A showed quite high antibacterial efficiency against E. coli. With the excellent performance as described above, GOM-A could be used to purify and desalt water.

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