ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Computational insights for K⁺- versus Na⁺-containing aluminosilicate species and their initial key reactions at experimentally relevant pH

Rajesh Patidar, Hariom Gupta, Saloni Verma, and Sanyukta Rewal

CSIR-Advanced Materials and Processes Research Institute, Bhopal, India

E-mail: rpatidar@ampri.res.in

Received: 4 November 2024  Accepted: 8 April 2025

Abstract:

Mostly the geopolymers have been synthesized by using NaOH/Na₂SiO₃ or KOH/K₂SiO₃ as activators, which, respectively, provides sodium and potassium counter-cations to the geopolymeric framework. A few experimental studies comparatively accounted better compressive strength of K-geopolymer against Na-geopolymer. However, the detailed comparative account of the fundamental chemical species (silicates, aluminates and aluminosilicates) and their initial key reactions (deprotonation and dimerization) with both of the experimentally relevant counter-cations, i.e., sodium and potassium, is lacking in the literature. Therefore, in this computational research work, we have obtained and compared the DFT optimized geometries of silicate, aluminate monomers and their dimers possessing both the experimentally relevant counter-cations (Na⁺ and K⁺). The initial reactions of the geopolymerization process, i.e., deprotonation and dimerization, with both the counter-cations at experimentally relevant pH 11 have also been compared.

Keywords: Glass-ionomer cement; Inorganic Chemistry; Potassium; Reactive Precursor; Reactivity of Clusters; Zeolites; Sodium; Potassium; Silicate; Aluminate; Aluminosilicate

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-025-04059-8

Chemical Papers 79 (7) 4331–4347 (2025)