The Formation and Properties of Zeolite-A and Zeolite-X through Geopolymerisation of Metakaolin

2018 ◽  
Vol 273 ◽  
pp. 167-174 ◽  
Author(s):  
Subaer ◽  
Hamzah Fansuri

This study was aimed at experimentally investigate the formation of zeolite-A and zeolite-X through geopolymerization routes. The samples were prepared by alkali-activation of metakaolinite at 70 °C with Si:Al = 1.04 and 1.25 and Na:A l= 0.6, 0.8, 1.0 while keeping the molar ratio of H2O:Na2O = 10. The physical and mechanical properties of the resulting materials were characterized by means of bulk density and porosity measurement, compressive strength and Vickers microhardness tests. Crystallinity level and the phase of the samples was examined by X-Ray Diffraction (XRD) while morphology and elemental composition of the samples were examined by Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS). It was found that zeolite-A and zeolite-X were able to produce through geopolymerisation of metakaolin. XRD and SEM-EDX analysis results showed that these materials were composed of zeolite-A or zeolite-X together with amorphous geopolymer. The zeolite X was only formed when ratio of Si:Al is 1.25 while zeolite A was formed at all ratio except ata Si:Al=1.25 and Na:Al=1.0. These materials have relatively low hardness and compressive strength, low density and high apparent porosity.


Author(s):  
Intan Ayu Safitri ◽  
Iis Siti Jahro

This study aims to determine the effect of the Si/Al molar ratio and the number of Na2EDTA additions on the purity and crystallinity levels of the synthesized zeolite X. zeolite X was synthesized by hydrothermal method at 70°C and 120°C for 3 and 6 hours, respectively. In the synthesis of zeolite X used boiler ash and aluminum foil waste. The results of characterization using Fourier Transform Infra Red (FT-IR) and X-Ray Diffraction (XRD) showed that the level of purity and crystallinity of the synthesized zeolite X was influenced by the variation of Si/Al molar rasio and amount of Na2EDTA addition. The zeolite with the best quality was obtained from the synthesis with a Si/Al molar ratio of 1.6 and the amount of Na2EDTA added as much as 3.0 g. The synthesized zeolite X has a purity level of 75% and a degree of crystallinity with a total intensity of 845.



Clay Minerals ◽  
2018 ◽  
Vol 53 (4) ◽  
pp. 657-663 ◽  
Author(s):  
Magdalena Król ◽  
Piotr Rożek

ABSTRACTThe aim of this research was to determine the temperature of kaolin calcination in order to obtain an intermediate product (metakaolin) for the synthesis of geopolymers with potential application as self-supporting zeolitic membranes. The products obtained were analysed with X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). The structural analysis of the metakaolins obtained suggested that the optimal temperature for the proposed application is 700°C. After alkali activation of metakaolin, it is possible to obtain zeolite A and hydroxysodalite. The factors analysed, determining the type and quantity of crystalline phases, were activation temperature and concentration of sodium hydroxide solution (activator). The largest amounts of zeolites were obtained by alkali activation with 9 mol/dm3 NaOH solution at 70°C.



Materials ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 383 ◽  
Author(s):  
R. A. Gado ◽  
Marek Hebda ◽  
Michal Łach ◽  
Janusz Mikuła

This study was conducted to investigate the influence of various reaction conditions, namely the silica modulus SiO2/Na2O, H2O/Na2O molar ratio, and liquid/solid ratio on the geopolymerization reaction of the waste fired clay bricks (Grog). The starting raw material and the generated geopolymer specimens produced by different geopolymerization reaction conditions have been characterized using different techniques: X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscope (SEM) and thermal analysis. Furthermore, physico–mechanical characterization has been carried out through the determination of bulk density, porosity, water absorption, and compressive strength for each sample at interval curing times of up to 28 days. The results indicated that the geopolymerization system of the waste fired clay bricks is influenced by the investigated reaction conditions at room temperature. The compressive strength of the geopolymer sample produced at optimum conditions increased significantly by up to 37.5 MPa, in comparison with 4.5 MPa for other conditions. Finally, an optimum recommendation and useful conclusions concerning the recycling and utilization of this waste material through the geopolymerization process are made for compatibility with construction applications.



2020 ◽  
Vol 9 (1) ◽  
pp. 396-409 ◽  
Author(s):  
Sara Ahmed ◽  
Tao Meng ◽  
Mazahir Taha

AbstractRecycling of red mud (RM) has attracted more attention in recent years due to severe environmental problems caused by landfilling. The effect of composition optimization and Nano-strengthening on the properties of a binder based on RM was studied in this paper. Results showed that modifying ratios of main oxides and adding Nano-SiO2 could obviously affect the mechanical properties and microstructure of the binder. Specimens with high SiO2/Al2O3 molar ratio (S/A) displayed considerable increase in compressive strength, while decreasing Na2O/Al2O3 molar ratio (N/A) improved the workability of the fresh mix. The compressive strength was developed significantly to be 45 MPa at 28 days by adding Nano-SiO2 with 0.4 wt.% of RM. Phase transformation and microstructure change at different stages of RM decomposition and binder geopolyerization were investigated by X-ray diffraction (XRD), Fourier transformation infrared (FTIR) and Scanning electron microscopy (SEM). The results of this study may provide a prospective method to use RM more widely in construction applications.



2016 ◽  
Vol 841 ◽  
pp. 186-192 ◽  
Author(s):  
Hamzah Fansuri ◽  
I’Is M. Anisatun ◽  
Anif Fatmawati ◽  
Wahyu Prasetyo Utomo ◽  
Warih Supriadi ◽  
...  

This study investigates the immobilization of Cd2+ and Cr3+ by using geopolymer paste based on PT. IPMOMI fly ash. The best composition of geopolimers paste was determined based on the highest magnitude of its 7 days compressive strength. Geopolymer pastes were prepared by varying SiO2/Al2O3 and Na2O/SiO2 molar ratio of the starting materials. X-Ray Diffraction (XRD) and Scanning Electron Microscope (SEM) were employed to examined these compositions. The molar ratio of SiO2/Al2O3 6.46 was found to produce the highest compressive strength of the resulting geopolymer paste, i.e 25 MPa and increased to 33.17 MPa by adjusting the ratio of Na2O/SiO2 to 0.65. Cd2+ and Cr3+ cations were added into geopolymers resin at the level of 1000 – 16000 ppm (mg/kg fly ash) and it was found to improve their compressive strength. The addition of 4000 ppm of Cd2+ increased the compressive strength to 38.6 MPa while the inclusion of 6800 ppm of Cr3+ reached 47.83 MPa. Further addition of cations reduced these values and the lowest compressive strength was observed on the addition of 16000 ppm of Cd2+ and Cr3+, i.e 8.65 MPa and 4.39 MPa, respectively. Leaching test was conducted by using Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES) and the distribution of heavy metal cations were examined by using SEM-EDX. The results showed that geopolymer pastes were able to immobilize Cr3+ at the studied level as there was no trace of Cr3+ detected after 6.5 hours of leaching. Geopolymer pastes were also found to completely immobilize Cd2+ at the level of 1000 ppm albeit the addition of 16000 ppm results in 6.26% leached out of this cation.



2011 ◽  
Vol 493-494 ◽  
pp. 588-593 ◽  
Author(s):  
N. Demirkol ◽  
Onur Meydanoglu ◽  
Hasan Gökçe ◽  
F.N. Oktar ◽  
E.S. Kayali

In this study, microstructures and mechanical properties of sheep hydroxyapatite (SHA) and commercial synthetic hydroxyapatite (CSHA)-MgO composites were investigated. The production of hydroxyapatite (HA) from natural sources is preferred due to economical and time saving reasons. The goal of development of SHA and CSHA based MgO composites is to improve mechanical properties of HA. SHA and CSHA composites were prepared with the addition of different amounts of MgO and sintered at the temperature range of 1000-1300 °C. The physical and mechanical properties were determined by measuring density, compression strength and Vickers microhardness (HV). Structural characterization was carried out with X-ray diffraction (XRD) and scanning electron microscopy (SEM) studies. In all composites, mean density values and mechanical properties increased with increasing sintering temperature. The increase of MgO content in SHA-MgO composites showed better mechanical properties in contrast to CSHA-MgO composites. Although the highest hardness and compression strength values were obtained at the SHA-10wt% MgO composite sintered at 1300°C, higher hardness and compression strength values were achieved with 5 wt% MgO addition at the CSHA-MgO composites when compared to SHA-MgO composites sintered between 1000-1200°C.



2018 ◽  
Author(s):  
Tasneem Siddiquee ◽  
Abdul Goni

Chemical treatment of CoX<sub>2</sub><b><sup>. </sup></b>6H<sub>2</sub>O (X = Cl, Br, I) with the potentially tridentate PNP pincer ligand 2,6-bis(di-<i>tert</i>-butylphosphinomethyl)pyridine in 1:1 molar ratio results in cobalt(II) halide-PNP pincer complexes. The effect of the hydrated metal source on molecular structure and geometry of the complexes was studied by single crystal X-ray diffraction analysis. The complexes are neutral and the cobalt center adopts a penta-coordinate system with potential atropisomerization. Within the unit cell there are two distinct molecules per asymmetric unit. One of the two phosphorus atoms in the PNP ligand was observed to be partially oxidized to phosphinoxide. Disorder in the structure reflects a mixture of square pyramidal and distorted tetrahedral geometry.



Crystals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 218
Author(s):  
Carlos Alberto Ríos-Reyes ◽  
German Alfonso Reyes-Mendoza ◽  
José Antonio Henao-Martínez ◽  
Craig Williams ◽  
Alan Dyer

This study reports for the first time the geologic occurrence of natural zeolite A and associated minerals in mudstones from the Cretaceous Paja Formation in the urban area of the municipality of Vélez (Santander), Colombia. These rocks are mainly composed of quartz, muscovite, pyrophyllite, kaolinite and chlorite group minerals, framboidal and cubic pyrite, as well as marcasite, with minor feldspar, sulphates, and phosphates. Total organic carbon (TOC), total sulfur (TS), and millimeter fragments of algae are high, whereas few centimeters and not biodiverse small ammonite fossils, and other allochemical components are subordinated. Na–A zeolite and associated mineral phases as sodalite occur just beside the interparticle micropores (honeycomb from framboidal, cube molds, and amorphous cavities). It is facilitated by petrophysical properties alterations, due to processes of high diagenesis, temperatures up to 80–100 °C, with weathering contributions, which increase the porosity and permeability, as well as the transmissivity (fluid flow), allowing the geochemistry remobilization and/or recrystallization of pre-existing silica, muscovite, kaolinite minerals group, salts, carbonates, oxides and peroxides. X-ray diffraction analyses reveal the mineral composition of the mudstones and scanning electron micrographs show the typical cubic morphology of Na–A zeolite of approximately 0.45 mμ in particle size. Our data show that the sequence of the transformation of phases is: Poorly crystalline aluminosilicate → sodalite → Na–A zeolite. A literature review shows that this is an unusual example of the occurrence of natural zeolites in sedimentary marine rocks recognized around the world.



Catalysts ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 346
Author(s):  
Sonam Goyal ◽  
Maizatul Shima Shaharun ◽  
Ganaga Suriya Jayabal ◽  
Chong Fai Kait ◽  
Bawadi Abdullah ◽  
...  

A set of novel photocatalysts, i.e., copper-zirconia imidazolate (CuZrIm) frameworks, were synthesized using different zirconia molar ratios (i.e., 0.5, 1, and 1.5 mmol). The photoreduction process of CO2 to methanol in a continuous-flow stirred photoreactor at pressure and temperature of 1 atm and 25 °C, respectively, was studied. The physicochemical properties of the synthesized catalysts were studied using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and photoluminescence (PL) spectroscopy. The highest methanol activity of 818.59 µmol/L.g was recorded when the CuZrIm1 catalyst with Cu/Zr/Im/NH4OH molar ratio of 2:1:4:2 (mmol/mmol/mmol/M) was employed. The enhanced yield is attributed to the presence of Cu2+ oxidation state and the uniformly dispersed active metals. The response surface methodology (RSM) was used to optimize the reaction parameters. The predicted results agreed well with the experimental ones with the correlation coefficient (R2) of 0.99. The optimization results showed that the highest methanol activity of 1054 µmol/L.g was recorded when the optimum parameters were employed, i.e., stirring rate (540 rpm), intensity of light (275 W/m2) and photocatalyst loading (1.3 g/L). The redox potential value for the CuZrIm1 shows that the reduction potential is −1.70 V and the oxidation potential is +1.28 V for the photoreduction of CO2 to methanol. The current work has established the potential utilization of the imidazolate framework as catalyst support for the photoreduction of CO2 to methanol.



2017 ◽  
Vol 866 ◽  
pp. 199-203
Author(s):  
Chidchanok Chainej ◽  
Suparut Narksitipan ◽  
Nittaya Jaitanong

The aims of this research were study the microstructures and mechanical properties for partial replacement of cement with Fly ash (FA) and kaolin waste (KW). Ordinary Portland cement were partially replaced with FA and KW in the range of 25-35% and 10-25% by weight of cement powder. The kaolin waste was ground for 180 minutes before using. The specimen was packing into an iron mold which sample size of 5×5×5 cm3. Then, the specimens were kept at room temperature for 24 hours and were moist cured in the incubation lime water bath at age of 3 days. After that the specimens were dry cured with plastic wrap at age of 3, 7, 14 and 28 days. After that the compounds were examined by x-ray diffraction patterns (XRD) and the microstructures were examined by scanning electron microscopy (SEM). The compressive strength was then investigated.



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