Multinuclear MAS NMR Characterization of Fly‐Ash‐Based Advanced Sodium Aluminosilicate Geopolymer: Exploring Solid‐State Reactions

Abstract

Advanced geopolymerization includes concept of just addition of water to ready mixture of dry precursor powder. For exploring the coordination environments of binary glass systems, this work presents multinuclear MAS NMR analysis of advanced geopolymer produced by solid state mechanochemical co-grinding of raw materials. The crystalline and amorphous phases of advanced geopolymer were already characterized with XRD in our previous study. This study focus on multinuclear (29Si, 27Al and 23Na) MAS NMR analysis for exploring the coordination environments of Si/Al/Na nuclei in advanced geopolymer. 29Si, 27Al and 23Na MAS NMR spectra of fly ash, advanced geopolymeric precursor material and advanced geopolymer are qualitatively estimated which enables an understanding of insertion of Al in silicate network ensuing solid state reactions during mechanochemical cogrinding process. By combining the NMR interpretations, it can be suitably said that mechanochemical co-grinding is a feasible way to induce local defects in amorphous Si/Al content which lead to variation in bond angles and variations in Si/Al constellations. Results may be very useful to understand framework connectivity, chemistry and behavior of advanced geopolymers produced by solid state route and the developed advanced geopolymer finds its potential application as "ready to use" cementitious material for large scale commercialization.

Rheological, fresh, and mechanical properties of mechanochemically activated geopolymer grout: A comparative study with conventionally activated geopolymer grout

“…Sodium silicate (Na 2 SiO 3 ) was used in two forms, a powder form (metasilicate-Penta) for preparing mechanochemical geopolymer and a liquid solution for preparing the conventional geopolymer. Based on previously published works that adopted the mechanochemical activation approach, a ratio of Na 2 SiO 3 /NaOH = 0.5 was selected to prepare the alkaline activator [49,[67][68][69][70]. Table 1 displays the chemical and physical properties of the precursor components (FA and slag) and sodium silicate in both liquid and powder forms.…”

Metal ion effect on pore size reduction in Mesoporous Aluminosilicate in the presence of TETA as a template and its catalytic performance of CO2 decomposition at lower temperature

“…Furthermore, this spectrum aids in determining the tetrahedral coordination of Al in the framework [38] . Both materials have only one 27 Al chemical shift value of 50 ppm, representing the tetrahedral coordination of Al (AlO 4 ) found in AlSiO 4 ‐33 andCo‐AlSiO 4 ‐15 [39,40] . There is no resonance line at about 0 ppm for either material, indicating the absence of Al (VI) fold geometry (AlO 6 ) [41] …”

Performance Optimization of FA-GGBS Geopolymer Based on Response Surface Methodology

“…The resonance peaks of Q 1 and Q 2 appeared in Z0, Z20, and Z20, and the intensity of the Q 1 resonance peak decreased in the order Z0 > Z20 > Z13, while the intensity of the Q 2 resonance peak increased in the order Z13 > Z20 > Z0. The Q 2 resonance peak is more substantial in the Z13 specimen, and the C-S-H gel generated at this ratio has more C-S-H in long chains with steric linkage [35][36][37]. The gel polymerization degree is more significant, so its intensity is naturally more vigorous.…”