Novel acid-based geopolymer synthesized from nanosized tubular halloysite: The role of precalcination temperature and phosphoric acid concentration

Zhang, Baifa; Guo, Haozhe; Yuan, Peng; Deng, Liangliang; Zhong, Xuemin; Li, Yun; Wang, Qiang; Liu, Dong

doi:10.1016/j.cemconcomp.2020.103601

Cited by 79 publications

(27 citation statements)

References 74 publications

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“…A promising alternative to conventional cementitious binders is the use of geopolymers, which proved to have a high acid resistance in several studies [ 4 , 5 ] and showed better performance compared to cementitious binders [ 6 , 7 , 8 , 9 , 10 , 11 ]. Geopolymers are inorganic aluminosilicate polymers, which are manufactured by mixing a powdery aluminosilicate precursor with an alkaline solution or an acid to dissolve the powder precursor and initiate the subsequent processes of geopolymerization [ 12 , 13 ].…”

Section: Introductionmentioning

confidence: 99%

Effect of Silica Fume on Metakaolin Geopolymers’ Sulfuric Acid Resistance

2021

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To demonstrate the importance of the Si/Al ratio in terms of geopolymer mix designs for acid resistance, a metakaolin-based geopolymer was modified by replacing the aforementioned precursor with different percentages of silica fume. Durability tests were performed by exposing geopolymers with varying amounts of silica fume (up to 9%) to sulfuric acid solution (pH 1) over a period of 84 days. Geopolymer samples were analyzed by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX) before and after 7, 14, 28, 56 and 84 days of exposure. To show the time-dependent change of the elemental composition in the corroded layer after sulfuric acid attack, SEM-EDX elemental mappings were conducted and divided into 100 µm segments to generate element-specific depth profiles. The results show that above a critical silica fume content, the erosion of the sample surface by complete dissolution can be prevented and higher amounts of silica fume lead to a significant densification of large (protective) areas of the corroded layer, which delays the progress of corrosion.

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Section: Introductionmentioning

confidence: 99%

Effect of Silica Fume on Metakaolin Geopolymers’ Sulfuric Acid Resistance

2021

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“…Furthermore, the presence of the adsorbed water bands (3413 and 1630 cm −1 ) on the FTIR spectrum of initial halloysite (Hal) means that halloysite was more hydrophilic than the others. The band at 906 cm −1 and 747 were caused by Al-O vibration associated with four coordinated Al [17,18].…”

Section: Ft-ir Spectra Of the Calcined Halloysite Powdersmentioning

confidence: 99%

Influence of calcined halloysite on technological & mechanical properties of wall tile body

Selli

Aker

Basaran

et al. 2021

Journal of Asian Ceramic Societies

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The effect of adding 0.1, 0.3, 0.6, 1.0 wt.% halloysite clay, which calcined at 600, 800, 1000 and 1200°C, to the standard wall tile slurry was studied. Wet milled halloysite was sieved with different sizes to examine the halloysite grain size effect. The granulated samples were pressed by applying a pressure of 30 MPa using a hydraulic press and made ready for sintering at 1150°C for 30 minutes. Detailed technological, mechanical and microstructural characterization studies were done on sintered samples. Compared to standard wall tile, almost all the halloysite added samples displayed similar technological properties but higher green and fired strength values. The produced sample with adding 0.6% halloysite (at 600°C calcined) by weight showed a higher firing strength with 28.75 MPa value than the minimum requirement (17.75 MPa). Observation of needlelike microstructure in the porcelain body led to establishing a simple relationship between the interlocking effects of thin needlelike mullite grains and increasing strength values. This study has shown that the addition of calcined halloysite may be an alternative to produce a thinner section wall tile product.

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“…According to the type of activator, it can be divided into two categories, namely alkali-based and acid-based geopolymers, resulting, respectively, from activation in alkaline and acid (phosphoric acid and humic acid) environments [ 3 , 4 ]. Alkali-based geopolymers are composed of cross-linked tetrahedral [AlO 4 ] 4− and [SiO 4 ] 4− units [ 5 ], but in the microstructure of acid-based geopolymers, [SiO 4 ] 4− is partially replaced by [PO 4 ] 5− to form a Si-Al-P binder system, which has stronger bonding and exhibits better properties, including higher compressive strength, lower efflorescence, and higher thermal stability [ 6 , 7 , 8 ]. Therefore, phosphate-based geopolymer can be used in cement-based construction as well as in the adsorption and immobilization of toxic metals [ 9 , 10 ].…”

Section: Introductionmentioning

confidence: 99%

Structure and Properties of Phosphate-Based Geopolymer Synthesized with the Spent Fluid Catalytic-Cracking (SFCC) Catalyst

Qian

Zhang

2022

Gels

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As a common industrial by-product, the spend fluid catalytic-cracking (SFCC) catalyst was used to prepare phosphate-based geopolymer for the first time. The structure and property of geopolymer with phosphoric acid concentration ranging from 6 to 14 mol/L was characterized by compressive strength measurements, X-ray powder diffraction (XRD), Fourier Transform Infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and 27Al and 29Si nuclear magnetic resonance (NMR). A stable binder was formed with the compressive strength in the range of 9.8 to 30.2 MPa when the acid concentration was between 6 and 12 mol/L. The higher concentration of acid can promote the dissolution of raw materials and formation of geopolymer gels. The coordination of silicon and aluminum in geopolymer gel synthesized with the SFCC catalyst and metakaolin is similar. Compared with the geopolymer with metakaolin, which forms more Si-O-Al bonds, in the networks of geopolymer with the SFCC catalyst, more Si(Al)-O-P bonds were formed. These results indicate that the SFCC catalyst can be an excellent raw material for the synthesis of phosphate-based geopolymer.

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Novel acid-based geopolymer synthesized from nanosized tubular halloysite: The role of precalcination temperature and phosphoric acid concentration

Cited by 79 publications

References 74 publications

Effect of Silica Fume on Metakaolin Geopolymers’ Sulfuric Acid Resistance

Effect of Silica Fume on Metakaolin Geopolymers’ Sulfuric Acid Resistance

Influence of calcined halloysite on technological & mechanical properties of wall tile body

Structure and Properties of Phosphate-Based Geopolymer Synthesized with the Spent Fluid Catalytic-Cracking (SFCC) Catalyst

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