The physico-mechanical influence of dehydroxylized activated local kaolin: A supplementary cementitious material for construction applications

Marfo, K.K.; Dodoo‐Arhin, David; Agyei-Tuffou, Benjamin; Nyankson, Emmanuel; Obada, David O.; Damoah, Lucas Nana Wiredu; Annan, Ebenezer; Yaya, Abu; Onwona-Agyeman, B.; Bediako, Mark

doi:10.1016/j.cscm.2019.e00306

Cited by 5 publications

(6 citation statements)

References 24 publications

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“…At 450 °C, the loss of OH lattice water begins, and dehydroxylation is essentially complete at 650 °C. This result is consistent with other forms of kaolin that have been dehydroxylated [33,34]. The loss of lattice water causes the crystalline structure of kaolinite to collapse, changing the coordination number of Al from VI to IV [35].…”

Section: The Properties Of Geopolymer Pastesupporting

confidence: 89%

“…The weight loss at 450 • C can be attributed to a pre-dehydration process produced by restructuring in the kaolin octahedral layer, as seen by the TG curve. At 450 • C, the loss of OH lattice water begins, and dehydroxylation is essentially complete at 650 • C. This result is consistent with other forms of kaolin that have been dehydroxylated [33,34]. The loss of lattice water causes the crystalline structure of kaolinite to collapse, changing the coordination number of Al from VI to IV [35].…”

Section: The Properties Of Geopolymer Pastesupporting

confidence: 82%

“…Figure 3a,b shows the FE-SEM image of kaolin and metakaolin, respectively. Th SEM image of metakaolin shows that the loss of water during dehydroxylation of kaolinit destroys dioctahedral kaolin and transforms the octahedrally coordinated Al layer into the tetrahedral form, but the Si-O sheets of the kaolin structure are largely conserved [33] The EDS result of metakaolin showed that Si = 22.7 wt.%, and Al = 22.0 wt.%. The geopolymer paste produced in this study was categorized as Na-Poly (sialate siloxo) type, with a molar ratio of the starting materials of Si: Al = 1.5 and Na: Al = 0.6.…”

Section: The Properties Of Geopolymer Pastementioning

confidence: 99%

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Pervaporation Membranes for Seawater Desalination Based on Geo–rGO–TiO2 Nanocomposites. Part 1: Microstructure Properties

et al. 2021

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This is the first of two papers about the synthesis and microstructure properties of the Geo–rGO–TiO2 ternary nanocomposite, which was designed to suit the criteria of a pervaporation membrane for seawater desalination. The performance and capability of Geo–rGO–TiO2 as a seawater desalination pervaporation membrane are described in the second paper. A geopolymer made from alkali-activated metakaolin was utilized as a binder for the rGO-TiO2 nanocomposite. A modified Hummer’s method was used to synthesize graphene oxide (GO), and a hydrothermal procedure on GO produced reduced graphene oxide (rGO). The adopted approach yielded high-quality GO and rGO, based on Raman spectra results. The nanolayered structure of GO and rGO is revealed by Transmission Electron Microscopy (TEM) images. The Geo–rGO–TiO2 ternary nanocomposite was created by dispersing rGO nanosheets and TiO2 nanoparticles into geopolymer paste and stirring it for several minutes. The mixture was then cured in a sealed mold at 70 °C for one hour. After being demolded, the materials were kept for 28 days before being characterized. Fourier Transform Infrared (FTIR) and X-ray Diffraction (XRD) measurements revealed that the geopolymer matrix efficiently bonded the rGO and TiO2, creating nanocomposites. Scanning Electron Microscopy (SEM) coupled with Energy Dispersive Spectroscopy (EDS) was used to examine the morphology of the outer layer and cross-sections of nanocomposites, and the results displayed that rGO were stacked on the surface as well as in the bulk of the geopolymer and will potentially function as nanochannels with a width of around 0.36 nm, while TiO2 NPs covered the majority of the geopolymer matrix, assisting in anti-biofouling of the membranes. The pores structure of the Geo–rGO–TiO2 were classified as micro–meso pores using the Brunauer–Emmet–Teller (BET) method, indicating that they are appropriate for use as pervaporation membranes. The mechanical strength of the membranes was found to be adequate to withstand high water pressure during the pervaporation process. The addition of rGO and TiO2 NPs was found to improve the hyropobicity of the Geo–rGO–TiO2 nanocomposite, preventing excessive seawater penetration into the membrane during the pervaporation process. The results of this study elucidate that the Geo–rGO–TiO2 nanocomposite has a lot of potential for application as a pervaporation membrane for seawater desalination because all of the initial components are widely available and inexpensive.

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Section: The Properties Of Geopolymer Pastesupporting

confidence: 89%

Section: The Properties Of Geopolymer Pastesupporting

confidence: 82%

Section: The Properties Of Geopolymer Pastementioning

confidence: 99%

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Pervaporation Membranes for Seawater Desalination Based on Geo–rGO–TiO2 Nanocomposites. Part 1: Microstructure Properties

et al. 2021

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“…Figure 3(B) however, has patches of cellulose fibers in irregular shapes, resulting in some agglomeration though the matrix generally looks homogeneous. The effects of the reinforcements in the composites are due to the interaction between the matrix and the reinforcement as reported by [ 28 ] . It is interesting to note here that the common challenge of clay particle and fiber agglomerations, which often leads to weaker links in the composite and therefore compromises the mechanical behavior of the composites, is absent in this case.…”

Section: Resultsmentioning

confidence: 99%

Comparative analyses of rice husk cellulose fiber and kaolin particulate reinforced thermoplastic cassava starch biocomposites using the solution casting technique

et al. 2021

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The potential of biodegradable packaging materials from thermoplastic cassava starch (TPS) reinforced with rice husk cellulose fibers (RHCF) and kaolin particulates (KP) using the solution casting method has been presented. This involved the blending of TPS and RHCF/KP in a plasticizer of ~4 ml of glycerol and ~45 ml of distilled water at 125°C and stirred at 60 rpm until a gel was formed. The gel was cast into sheets and bone‐shaped tensile specimens and allowed to dry for 5 days and characterized. The results show a semicrystalline structure for TPS with an ~36% increase in crystallinity after reinforcement. The O‐H bond stretching and the C‐H bending bonds due to starch–glycerol reactions were the common functional groups in TPS–RHCF biocomposites, and Si‐O‐C bonds were characteristics of the silica phase in the kaolin. The water vapor transmission rate (WVTR) reduced to ~34% with KP reinforcements from ~238 g/m.day to 177 g/m.day and to ~74 g/m.day and ~164% for TPS–RHCF. The strength increased with up to 50 wt% kaolin content; ~0.96 MPa yield strength and ~2.60 MPa ultimate tensile strength (UTS) were recorded. For the RHCF reinforced composites, TPS‐50 wt% also showed high strengths of ~0.96 MPa yield strength and ~3.50 MPa UTS. The WVTR reduced as content of kaolin was increased. Typically, from 0 to 30 wt% volume fraction of kaolin, the WVTR was reduced by ~34% to 177 g/m.day for TPS–kaolin and by ~164% to ~74 g/m.day in TPS–RHCF. The as‐prepared biocomposites have potential as good packaging materials.

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“…Figure 7 shows plate like kaolin SEM micrographs. It is evident that the kaolin morphology consisted of crystals with sharp edges, hexagonal shapes, rods, plates with corrosion, and irregular shapes [ 22 , 49 , 111 ]. The geopolymer made from kaolin has the benefit of being reliably created, with known properties during both preparation and development.…”

Section: Properties Of the Kaolin Ceramic Geopolymersmentioning

confidence: 99%

Geopolymer Ceramic Application: A Review on Mix Design, Properties and Reinforcement Enhancement

et al. 2022

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Geopolymers have been intensively explored over the past several decades and considered as green materials and may be synthesised from natural sources and wastes. Global attention has been generated by the use of kaolin and calcined kaolin in the production of ceramics, green cement, and concrete for the construction industry and composite materials. The previous findings on ceramic geopolymer mix design and factors affecting their suitability as green ceramics are reviewed. It has been found that kaolin offers significant benefit for ceramic geopolymer applications, including excellent chemical resistance, good mechanical properties, and good thermal properties that allow it to sinter at a low temperature, 200 °C. The review showed that ceramic geopolymers can be made from kaolin with a low calcination temperature that have similar properties to those made from high calcined temperature. However, the choice of alkali activator and chemical composition should be carefully investigated, especially under normal curing conditions, 27 °C. A comprehensive review of the properties of kaolin ceramic geopolymers is also presented, including compressive strength, chemical composition, morphological, and phase analysis. This review also highlights recent findings on the range of sintering temperature in the ceramic geopolymer field which should be performed between 600 °C and 1200 °C. A brief understanding of kaolin geopolymers with a few types of reinforcement towards property enhancement were covered. To improve toughness, the role of zirconia was highlighted. The addition of zirconia between 10% and 40% in geopolymer materials promises better properties and the mechanism reaction is presented. Findings from the review should be used to identify potential strategies that could develop the performance of the kaolin ceramic geopolymers industry in the electronics industry, cement, and biomedical materials.

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The physico-mechanical influence of dehydroxylized activated local kaolin: A supplementary cementitious material for construction applications

Cited by 5 publications

References 24 publications

Pervaporation Membranes for Seawater Desalination Based on Geo–rGO–TiO2 Nanocomposites. Part 1: Microstructure Properties

Pervaporation Membranes for Seawater Desalination Based on Geo–rGO–TiO2 Nanocomposites. Part 1: Microstructure Properties

Comparative analyses of rice husk cellulose fiber and kaolin particulate reinforced thermoplastic cassava starch biocomposites using the solution casting technique

Geopolymer Ceramic Application: A Review on Mix Design, Properties and Reinforcement Enhancement

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