scholarly journals Synthesis and Characterization of Composite Membranes Based on Carbon Functionalized with Gold Nanoparticles

2019 ◽  
Vol 56 (2) ◽  
pp. 309-314
Author(s):  
Alexandra Georgiana Vatui (Moise) ◽  
Sorina Nicoleta Valsan ◽  
Corneliu Fratila ◽  
Andreea Nicoleta Ghita ◽  
Arcadii Sobetkii ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Graphene Oxide ◽  
Cross Sections ◽  
Self Assembly ◽  
Carbon Nanostructures ◽  
Chemical Reduction ◽  
Membrane Surface ◽  
Composite Membranes ◽  
The Matrix ◽  
Experimental Laboratory

The purpose of this experimental laboratory work is to obtain composite membranes having carbon and gold nanoparticles in the matrix. Consideration was made of using graphene oxide, a material which, under certain conditions, can generate membranes by a self-assembly process under vacuum in an aqueous or organic medium. The cellulose acetate (CA) - graphene oxide (GO) composite membranes have been functionalized with gold nanoparticles (AuNP) by two technological processes: thermal evaporation and ultrasonic mixing of stable graphene oxide and gold suspensions. The stable suspensions containing gold nanoparticles were obtained by chemical reduction of aqueous solutions of Tetrachloroauric acid trihydrate (HAuCl4) precursors with sodium citrate under high temperature conditions. Dispersibility of carbon nanostructures and precious metal nanoparticles has been studied with a DLS granulometer - Malvern Instruments Zetasizer ZS90. It was determined the mean particle size and Zeta potential function of the suspensions pH. The graphite based membranes were further subjected to various characterizations techniques. It was found that both the surfaces and the cross-sections were functionalized with gold particles. The presence of Au particles was revealed both on the membrane surface and also inside its structure. Hydrophilic tests demonstrate that the membrane filters have potential to be used in various applications.

scholarly journals Sunlight-Driven Photothermal Effect of Composite Eggshell Membrane Coated with Graphene Oxide and Gold Nanoparticles

2019 ◽  
Vol 9 (20) ◽  
pp. 4384
Author(s):  
Ling Wang ◽  
Bin Tang ◽  
Ji Zhou ◽  
Hai Zhao ◽  
Wu Chen ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Graphene Oxide ◽  
Photoelectron Spectroscopy ◽  
Chemical Elements ◽  
Membrane Surface ◽  
Composite Membranes ◽  
Eggshell Membrane ◽  
Photothermal Effect ◽  
Photothermal Conversion ◽  
3D Network

Eggshell membrane (ESM), which consists of unique interwoven shell membrane fibers, provides a unique supporting platform for functional nanoparticles in catalysis and sensing. This work reports a novel strategy for fabricating sunlight-driven photothermal conversion composite membranes by loading graphene oxide (GO) and gold nanoparticles (AuNPs) on the three-dimension (3D) network structured eggshell membrane. Surface morphologies and chemical elements were characterized by scanning electron microscopy and X-ray photoelectron spectroscopy. High photothermal conversion under simulated sunlight irradiation, which may be caused by the synergistic effect of GO and AuNPs, was achieved by coating both GO and AuNPs onto ESM. The temperature of ESM modified with AuNPs, and then GO increased from 26.0 °C to 49.0 °C after 10 min of light irradiation. Furthermore, the nanoscaled GO and AuNPs could add benefit to the heating localization of the obtained composite membrane. It is expected this biocompatible ESM modified with GO and AuNPs would have great potential in drug release and photothermal therapy applications.

scholarly journals Electrodeposition–Assisted Assembled Multilayer Films of Gold Nanoparticles and Glucose Oxidase onto Polypyrrole-Reduced Graphene Oxide Matrix and Their Electrocatalytic Activity toward Glucose

Nanomaterials ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 993 ◽  
Author(s):  
Baoyan Wu ◽  
Shihua Hou ◽  
Yongyong Xue ◽  
Zhan Chen
Keyword(s):  
Gold Nanoparticles ◽  
Graphene Oxide ◽  
Glucose Oxidase ◽  
Reduced Graphene Oxide ◽  
Self Assembly ◽  
Electrocatalytic Activity ◽  
Multilayer Films ◽  
Glucose Biosensor ◽  
Future Design ◽  
Reduced Graphene

The study reports a facile and eco-friendly approach for nanomaterial synthesis and enzyme immobilization. A corresponding glucose biosensor was fabricated by immobilizing the gold nanoparticles (AuNPs) and glucose oxidase (GOD) multilayer films onto the polypyrrole (PPy)/reduced graphene oxide (RGO) modified glassy carbon electrode (GCE) via the electrodeposition and self-assembly. PPy and graphene oxide were first coated on the surface of a bare GCE by the electrodeposition. Then, AuNPs and GOD were alternately immobilized onto PPy-RGO/GCE electrode using the electrodeposition of AuNPs and self-assembly of GOD to obtain AuNPs-GOD multilayer films. The resulting PPy-RGO-(AuNPs-GOD)n/GCE biosensors were used to characterize and assess their electrocatalytic activity toward glucose using cyclic voltammetry and amperometry. The response current increased with the increased number of AuNPs-GOD layers, and the biosensor based on four layers of AuNPs-GOD showed the best performance. The PPy-RGO-(AuNPs-GOD)4/GCE electrode can detect glucose in a linear range from 0.2 mM to 8 mM with a good sensitivity of 0.89 μA/mM, and a detection limit of 5.6 μM (S/N = 3). This study presents a promising eco-friendly biosensor platform with advantages of electrodeposition and self-assembly, and would be helpful for the future design of more complex electrochemical detection systems.

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 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.

Spray-assisted layer-by-layer self-assembly of tertiary-amine-stabilized gold nanoparticles and graphene oxide for efficient CO2 capture

2020 ◽  
Vol 601 ◽  
pp. 117905 ◽  
Author(s):  
Jiwoong Heo ◽  
Moonhyun Choi ◽  
Daheui Choi ◽  
Hyejoong Jeong ◽  
Hyun Young Kim ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Graphene Oxide ◽  
Co2 Capture ◽  
Tertiary Amine ◽  
Self Assembly ◽  
Layer By Layer

scholarly journals Effect of Graphene Oxide Synthesis Method on Properties and Performance of Polysulfone-Graphene Oxide Mixed Matrix Membranes

Nanomaterials ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 769 ◽  
Author(s):  
Safae Sali ◽  
Hamish R. Mackey ◽  
Ahmed A. Abdala
Keyword(s):  
Graphene Oxide ◽  
Water Flux ◽  
Synthesis Method ◽  
Composite Membranes ◽  
Mixed Matrix Membranes ◽  
Great Promise ◽  
Mixed Matrix ◽  
Water Emulsion ◽  
The Matrix ◽  
And Performance

Graphene oxide (GO) has shown great promise as a nanofiller to enhance the performance of mixed matrix composite membranes (MMMs) for water treatment applications. However, GO can be prepared by various synthesis routes, leading to different concentrations of the attached oxygen functional groups. In this research, GO produced by the Hummers’, Tour, and Staudenmaier methods were characterized and embedded at various fractions into the matrix of polysulfone (PSf) and used to prepare microfiltration membranes via the phase inversion process. The effects of the GO preparation method and loading on the membrane characteristics, as well as performance for oil removal from an oil-water emulsion, are analyzed. Our results reveal that GO prepared by the Staudenmaier method has a higher concentration of the more polar carbonyl group, increasing the membrane hydrophilicity and porosity compared to GO prepared by the Hummers’ and Tour methods. On the other hand, the Hummers’ and Tour methods produce GO with larger sheet size, and are more effective in enhancing the mechanical properties of the PSf membrane. Finally, all MMMs exhibited improved water flux (up to 2.7 times) and oil rejection, than those for the control PSf sample, with the optimum GO loading ranged between 0.1–0.2 wt%.

Electrochemical Features of Bilirubin Oxidase Immobilized on Different Carbon Nanostructures

2013 ◽  
Vol 543 ◽  
pp. 13-17 ◽  
Author(s):  
Jaroslav Filip ◽  
Jana Šefčovičová ◽  
Peter Gemeiner ◽  
Jan Tkac
Keyword(s):  
Graphene Oxide ◽  
Carbon Nanostructures ◽  
Active Sites ◽  
High Efficiency ◽  
Direct Electron Transfer ◽  
Graphene Film ◽  
Modified Electrodes ◽  
Bilirubin Oxidase ◽  
Enzymatic Biofuel Cells ◽  
The Matrix

An electrode interface was prepared using a mixture of a cheap carbon nanomaterial KetjenBlack (KB) and carbon nanotubes (CNT) dispersed in a biopolymer chitosan. Bilirubin oxidase (BOD) was proved to adsorb effectively on such a nanointerface, retaining its catalytic activity for reduction of dioxygen to water, which was proved by cyclic voltammetry. Moreover, three distinct cathodic redox reactions were determined in the absence of oxygen, suggesting that KB/CNT template provides a suitable micro and nanoporosity for direct electron transfer between BOD and the modified electrodes revealing all three known active sites of BOD. Furthermore, BOD was adsorbed on graphene oxide with subsequent electrochemical reduction of graphene oxide into a conductive graphene film with BOD trapped within the matrix. Two active sites of BOD were observed on the electrode modified by graphene suggesting the enzyme is oriented in a different way compared to the KB/CNT nanointerface due to changes in the nature of functional groups within the nanocomposite, changed porosity of the nanointerface or as a result of electrochemical perturbation of the matrix during reduction of graphene oxide. A more detailed fundamental investigation of the influence of the nanointerface matrix on an adsorption and orientation of BOD will without any doubt allow us to tailor ability of such composites to reduce dioxygen to water with high efficiency, what is a feature important for construction of robust and effective biocathodes of enzymatic biofuel cells.

scholarly journals Magnetic field-induced self-assembly of chemically modified graphene oxide on cellulose fabrics for the fabrication of flexible conductive devices

Cellulose ◽  
2021 ◽  
Author(s):  
Huanxia Zhang ◽  
Wen Wu ◽  
Jie Zhou ◽  
Xinchao Zhang ◽  
Tantan Zhu ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Electrical Conductivity ◽  
Graphene Oxide ◽  
Self Assembly ◽  
Chemical Reduction ◽  
Volume Resistivity ◽  
Layer By Layer ◽  
Wearable Electronics ◽  
Washing Durability ◽  
Modified Graphene Oxide

AbstractIn this present study, we have successfully fabricated the cellulose fabric with excellent electrical conductivity by depositing the graphene oxide grafted with the modified ferroferric oxide (GOF) upon fabric substrate via layer-by-layer magnetic-field-induced self-assembly apporoach and followed by chemical reduction. The results indicated that the morphologies of graphene oxide nanosheets for three-layer deposited fabrics could form the highly oriented wrinkled structures, which resulted from the synergistic interactions of magnetic induction force on magnetic doublet, hydrogen bonds and van der Waals. The volume resistivity of the three-layer deposited fabric could reach to 64.8 Ω cm compared with that of pure RGO-coated viscose fabrics (137.94 Ω cm) in the previous work, which could be favorable for improving the electrical conductivity and decreasing the graphene oxide consumption. Furthermore, the three-layer deposited fabric possessed excellent washing durability even after twelve times water laundering. Our results suggested that the flexible GOF-coated fabric had great potential in conductive devices for wearable electronics, strain sensors, smart actuators and bioelectrodes and so on.

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