Structural and Chemical Properties of Geopolymer Gels Incorporated with Neodymium and Samarium

Nenadović, Snežana; Kljajević, Ljiljana; Ivanović, Marija; Mirković, Miljana; Radmilović, Nadežda; Rakočević, Lazar; Nenadović, Miloš

doi:10.3390/gels7040195

Cited by 9 publications

(3 citation statements)

References 60 publications

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“…The presence of the Nd 4d spectral line in the low-energy scale of the spectrum is a consequence of the amount of Nd concentration. Previous investigations showed that, at a lower dopant concentration, the Nd 4d line does not appear [ 37 ]. Detailed spectra od neodymium 3d and 4d spectral lines reveal the more pronounced contribution of Nd 3d 5/2-1 to 998.9 eV belonging to Nd (OH) 3 , as well as its contribution to 977.9 eV (Nd 3d 5/2-2), and can be attributed to pure Nd 2 O 3 , as shown in Figure 7 c. The ratio of the amounts of hydroxide and oxide phase offers information about the reaction rate of neodymium in the geopolymer matrix during alkaline activation.…”

Section: Resultsmentioning

confidence: 99%

Microstructural Analysis of Thermally Treated Geopolymer Incorporated with Neodymium

et al. 2023

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The following investigation presents the thermal treatment of geopolymer at 300 °C, 600 °C and 900 °C. We investigated what happens to the geopolymer base when incorporated with 1% and 5% of neodymium in the form Nd2O3. A total of six samples were synthesized. Geopolymer 1 contained 1% and geopolymer 2 contained 5% Nd2O3, and these samples were treated at 300 °C; then, samples geopolymer 3 and geopolymer 4 also had the same percentage composition of Nd2O3 and were treated at 600 °C, while samples geopolymer 5 and geopolymer 6were treated at 900 °C. Physical and chemical changes in the aluminosilicate geopolymer matrix were monitored. The incorporation of rare earths into the polymer network of aluminosilicates has been proven to disrupt the basic structure of geopolymers; however, with increased temperatures, these materials show even more unusual properties. Diffuse reflectance infrared Fourier transform (DRIFT) analysis showed that the intensity of the vibrational band decreases with the increase in temperature during thermal treatment, suggesting alterations in the chemical structure of the geopolymers. Transmission electron microscopy (TEM) analysis showed that the diameter of the nanoparticles containing Al2O3 is in the range 5–10 nm, while larger crystallites range from 30 to 80 nm. Scanning electron microscopy (SEM) analysis revealed that the temperature of the thermal treatment increases to 300 °C and 600 °C; the porosity of geopolymer increases in the form of the appearance of large pores and cracks in material. X-ray photoelectron spectroscopy (XPS) analysis was used to investigate the surface chemistry of geopolymers, including the chemical composition of the surface, the oxidation state of the elements, and the presence of functional groups. The UV/Vis spectra of the synthesized geopolymers doped with Nd3+ show interesting optical properties at 900 °C; the geopolymer matrix completely disintegrates and an amorphous phase with a rare-earth precipitate appears.

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Section: Resultsmentioning

confidence: 99%

Microstructural Analysis of Thermally Treated Geopolymer Incorporated with Neodymium

et al. 2023

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“…Because of the presence of zeolite A in the formulations of geopolymers based on Brazilian metakaolins [ 14 ], the consolidated geopolymers displayed high adsorption capacity within short times (between one and five minutes) for different cationic dyes, i.e., methylene blue, safranin, and malachite green from aqueous solutions. From the observation of such an encapsulating capability, the number of studies dedicated to different cations [ 15 , 16 , 17 , 18 , 19 ], anions [ 20 , 21 ], and larger molecular assemblages [ 22 ] has increased over the last few years.…”

Section: Introductionmentioning

confidence: 99%

Entrapment of Acridine Orange in Metakaolin-Based Geopolymer: A Feasibility Study

et al. 2023

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Few studies have explored the immobilization of organic macromolecules within the geopolymer matrix, and some have found their chemical instability in the highly alkaline geopolymerization media. The present work reports on the feasibility of encapsulating the potentially toxic acridine orange (AO) dye in a metakaolin based geopolymer while maintaining its structural integrity. The proper structural, chemical, and mechanical stabilities of the final products were ascertained using Fourier-transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD), thermogravimetric (TGA/DTG), and mechanical analyses, whereas the dye integrity and its stability inside the geopolymer were investigated by the UV-Vis analysis. In addition, the antimicrobial activity was investigated. The FT-IR and XRD analyses confirmed the geopolymerization occurrence, whereas the TGA/DTG and mechanical (compressive and flexural) strength revealed that the addition of 0.31% (AO mg/ sodium silicate L) of AO to the fresh paste did not affect the thermal stability and the mechanical properties (above 6 MPa in flexural strength and above 20 MPa for compressive strength) of the hardened product. UV-Vis spectroscopy revealed that the dye did not undergo chemical degradation nor was it released from the geopolymer matrix. The results reported herein provide a useful approach for the safe removal of toxic macromolecules by means of encapsulation within the geopolymer matrix.

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“…Geopolymers, also called geopolymer gels (Nenadović et al, 2021), are materials made from alumino-silicate materials, such as metakaolin (MEFISTO L05, 2022), furnace slag (Trinh et al, 2020) fly ash (Kristály et al, 2020) or precursors prepared synthetically via sol-gel method (Tsai et al, 2010), which are primarily composed of silicon dioxide, aluminium oxide, iron oxide and other oxides. They are formed by polycondensation in strongly basic environment, usually in hydroxide or silicate solution.…”

Section: Introductionmentioning

confidence: 99%

Modifying geopolymer wettability by plasma treatment and high-carbon fly ash

Růžek

Louda

Buczkowska

et al. 2022

Front. Built Environ.

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This paper deals with investigation of changes in geopolymer wettability with increasing mass fraction of high-carbon fly ash and surface treatment by cold atmospheric plasma (CAP) to determine the influence of fly ash on wettability and whether it is a viable method to increase surface wettability for further surface treatment. In this study, multiple samples of geopolymers were prepared, including those with 16% and 32% of high-carbon fly ash from coal-fired power station. Wettability of samples was then measured before and after plasma treatment, both on surface and cut surface by using static sessile drop method to measure the differences in contact angle. While addition of fly ash only had low effect on the wettability, as in most cases, it only lowered the initial contact angle without speeding up the speed of soaking for compact geopolymer and actually slowed the soaking for foamed geopolymer, plasma treatment had significant impact and made the geopolymer completely hydrophobic, making plasma treatment a viable method to increase geopolymer wettability.

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Structural and Chemical Properties of Geopolymer Gels Incorporated with Neodymium and Samarium

Cited by 9 publications

References 60 publications

Microstructural Analysis of Thermally Treated Geopolymer Incorporated with Neodymium

Microstructural Analysis of Thermally Treated Geopolymer Incorporated with Neodymium

Entrapment of Acridine Orange in Metakaolin-Based Geopolymer: A Feasibility Study

Modifying geopolymer wettability by plasma treatment and high-carbon fly ash

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