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Enhancing the hydrogen permeation of alumina composite porous membranes via graphene oxide addition
(2023-01-12)
Hankoy, Montree
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Phrompet, Chaiwat
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Ruttanapun, Chesta
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Kaewpengkrow, Prangtip Rittichote
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Vichaphund, Supawan
Graphene oxide (GO) membranes have attracted considerable interest for hydrogen (H<inf>2</inf>) purification applications. However, the addition of GO into matrix materials to enhance the efficiency of H<inf>2</inf> permeation remains a challenge. In this study, the fabrication of alumina/graphene oxide (AGO) composites containing varying contents of GO (0.5–3.0 wt.%) was investigated. The AGO composites were formed into pellets and sintered for 2 h at 1500 °C. Accordingly, the presence of GO in the membranes following sintering was confirmed by Raman spectroscopy. Additionally, the porosity of the AGO composites increased from 3.7% to 26.9% as the GO concentration increased from 0.5 wt.% to 3.0 wt.%. Furthermore, the average pore diameter of the AGO composites was in the range of 87–228 nm, and the pore size distribution was unimodal. The performance of the AGO membranes was investigated for the permeance of single gases H<inf>2</inf> and N<inf>2</inf> at 30–500 °C to evaluate their potential for H<inf>2</inf> separation applications. The AGO membranes with a GO addition of 2.5 and 3.0 wt.% exhibited a high hydrogen permeance of 232–410 × 10−6 mol m−2 s−1 Pa−1, which was approximately 10 times greater than that of pristine Al<inf>2</inf>O<inf>3</inf> membrane. Additionally, the ideal H<inf>2</inf>/N<inf>2</inf> selectivity values ranged from 4.02 to 4.20. Furthermore, gas permeation through the AGO membrane was observed to follow the Knudsen diffusion mechanism.
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Effect of graphene oxide nanoparticles on blast load resistance of steel fiber reinforced concrete
(2022-08-08)
Jamnam, Sittisak
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Maho, Buchit
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Techaphatthanakon, Apisit
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Ruttanapun, Chesta
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Aemlaor, Peerasak
Concrete structures may occasionally be subjected to both intentional or unintentional explosions which could cause casualties and damage to properties. Advance research on protective structures are important to enhance blast resistance of materials, and to protect life and properties. This study investigated the effect of graphene oxide nanoparticles (GO) on enhancing the blast resistance of fiber reinforced cement mortar (FRM). GO in solution was incorporated in steel fiber reinforced mortar at the rate of 0, 0.025, 0.050, 0.075, and 0.100 % by weight of cement. A series of experiments were carried out consisting of 2 stages: Stage 1) workability, setting time, compressive and flexural strength, and microstructure using SEM and XRD processes, and Stage 2) blasting loading test. The optimum GO dosage giving the highest compressive and flexural strengths from the 1st stage was determined and chosen to continue on the 2nd stage (blast loading test). The blasting tests were performed on panel specimens (500mmx1000mmx60mm) using TNT weighing ½ lb. (226.7 g) with three different standoff distances of 340, 400, and 460 mm. Results from Stage 1 on both flexural and compression tests indicated an optimum GO content of 0.025% by weight of cement. The workability was found to decrease with the increasing the GO content. The SEM images also revealed that the addition of GO nanoparticles reduced the porosity in the mortar matrix. For the blasting test, three damage patterns were observed: complete flexural failure, partial damage (flexural cracking), and no major damage, depending on the standoff distance and specimen type. The addition of GO can reduce the maximum and permanent deflections of the panel under blast loading. FRM panels with GO at 0.025% tested at the standoff distance of 460 mm showed the lowest level of damage.
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Effect of graphene oxide on single fiber pullout behavior
(2021-04-19)
Chindaprasirt, Prinya
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Sukontasukkul, Piti
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Techaphatthanakon, Apisit
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Kongtun, Suriyawan
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Ruttanapun, Chesta
The properties of fiber reinforced concrete (FRC) depends strongly on bond between fiber and cement matrix. Any change in matrix and fiber characteristics affects the bond behavior. In this study, the effect of graphene oxide on cement composite strength and bond behavior between fiber and cement matrix was investigated. The graphene oxide solution with concentration of 10 mg/ml was mixed with cement mortar at 0.05% by weight of cement. Four types of fibers viz., hooked end steel, double hooked end steel, polypropylene and glass fibers were tested by embedding in both plain cement mortar (M) and cement graphene mortar (GM). The single fiber pullout test was performed at the rates of 60 and 180 mm/min. Results were collected in form of failure mode, scanning electron microscope (SEM) images, bond-slip response, bond strength and energy absorption. SEM images showed that the failure modes depended on fiber type, matrix type and loading rate. The steel fibers showed almost no damage except for the change of hooked end shape at the fiber end. For polypropylene fiber, the fiber surface scraping was commonly observed while the debonding of coating material was observed for glass fiber. The bond strength was higher in GM mortar than that of M mortar and increased with the increase in loading rate. In the case of fiber type, steel fibers exhibited higher bond and energy absorption than both polypropylene and glass fibers.
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Electrical properties of bistable device based on graphene oxide composited with polyvinylpyrrolidone thin films
(2021-01-01)
Thiwawong, Thutiyaporn
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Songkeaw, Potiyan
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Onlaor, Korakot
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Tunhoo, Benchapol
This research studied the bistable properties of synthesized graphene oxide (GO) composited with polyvinylpyrrolidone (PVP). The devices were fabricated using a spin coating process on indium tin oxide (ITO)/glass substrate, and the top electrodes were prepared by thermal evaporation with the device structure of ITO/PVP:GO/Al. The PVP:GO films were characterized by Raman spectroscopy, Fourier-transform infrared spectroscopy, X-ray photoemission spectroscopy, and scanning electron microscopy. The current-voltage (I-V) characteristics of the fabricated device exhibited a maximum ON/OFF current ratio in the order of about 104 at a GO concentration of 4 wt%. The mechanism was explained by fitting with the results of the I-V measurement. Moreover, the retention test of the device was more than 2×104 s. The device showed the important characteristics of memory to be a candidate for data storage.
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Reduced graphene oxide thin film prepared by electrostatic spray deposition technique
(2019-03-15)
Songkeaw, Potiyan
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Onlaor, Korakot
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Thiwawong, Thutiyaporn
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Tunhoo, Benchapol
Reduced graphene oxide (rGO) thin films were prepared by one-step electrostatic spray deposition (ESD) technique with a precursor solution of graphene oxide in mixed alcohol solvent. The deposited rGO films showed decreasing thicknesses ranging from approximately 340 nm–120 nm as substrate temperature increased from 150 °C to 275 °C. Raman spectroscopy indicated lowest intensity ratio of D to G band (I <inf>D</inf> /I <inf>G</inf> ) of the rGO films at substrate temperature of 275 °C. Highest carbon per oxygen (C/O) ratio was also obtained at substrate temperature of 275 °C. The ESD technique was used for film deposition on an area of 5 × 5 cm 2 , while an acetone gas sensor based on single layer rGO film was fabricated by one-step ESD technique. Results indicated the possibility of controlling thickness components in the rGO film, and the capability of large-area production by this scalable ESD method.
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Ultrahigh linear sensitivity of capacitive humidity sensor base on bilayer structure of graphene oxide
(2019-03-01)
Pongampai, Satana
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Pengpad, Puttapon
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Meananeatra, Rattanawan
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Chaisriratanakul, Woraphan
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Thitirungraung, Wisut
Capacitive humidity sensor is designed on interdigitage electrodes (IDEs) by lithography process for nice humidity absorption and desorption. This paper proposed the IDEs humidity sensor base on bilayers sensing of graphene oxide (GO) structure by dip coating method. Each GO layer is held by covalent-bond forces from adhesive layer. It demonstrates durable of sensing layer material. Raman spectroscopy analysis is exhibited on GO presence and scanning electron microscope (SEM) explored on the GO bilayers structure. The IDEs/GO bilayers humidity sensor demonstrated ultrahigh sensitivity (up to 2014.61%) and linear responses at relative humidity (RH) ranges 10 to 70% while IDEs/GO single layer showed exponential responses. Moreover, it significantly improved on response (12 sec) and recovery times (18sec), a little hysteresis (up to 46.77%) and stable repeatability. Finally, the durable of IDEs/GO bilayers humidity sensor is exhibited by long-term ability measurement (time period 35 days). Therefore, these characteristics of GO bilayers structure base on adhesive layer are clearly demonstrated high performances for alternatively used with humidity sensor applications.
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Humidity sensor based on graphene oxide film prepared by simple drop-casting process
(2017-01-01)
Songkeaw, Potiyan
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Onlaor, Korakot
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Tunhoo, Benchapol
In this work, the film of graphene oxide was deposited by drop-casting process for humidity sensor device. The structural property of graphene oxide film was performed by Raman spectroscopy. The humidity device was fabricated onto the indium tin oxide, as the transparent electrode. The device exhibited the adsorption and desorption behaviors of humidity in a range of 23-93 %RH. The complex impedance measurement was used to explain the mechanisms of the humidity device. The equivalent circuit model of the device was demonstrated.
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The investigation of thermal effect on dynamical shape changing of solder paste by using double-view digital holography
(2015-01-01)
Thong-On, T.
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Prakobsang, T.
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Pethsanthad, W.
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Boonsri, C.
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Plaipichit, S.
In this paper we propose a modern technique to evaluate the shape changes of solder paste by using double-view in-line digital holography. We observed the transformation of three different kinds of solder paste composition: pure solder paste, solder paste mixed with 0.02%, 0.05%, 0.10% graphene (GPN) and 0.02%, 0.05%, 0.10% graphene oxide (GPNO), respectively. The shape of the solder pastes was investigated at different melt temperatures (i.e. 200°C, 250°C, and 300°C) for 30 seconds using a collimated beam propagating through the solder paste, then being double reflected on a mirror and second incident on another sides of the solder paste. The double images bearing beams were recorded with a CCD sensor simultaneously. The single recorded digital hologram from double view technique was reconstructed using digital holography. The results show that the double-view technique provides reliably data. Moreover, it would be developed for observing more than two images by single holography writing in the future.

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