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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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