2026-04-17T11:00:57Zhttps://riubu.ubu.es/oai/request

oai:riubu.ubu.es:10259/108602025-09-12T00:05:34Zcom_10259_4249com_10259_5086com_10259_2604col_10259_4250

Design of Experiments Approach for Efficient Heavy Metals Stabilization Using Metakaolin-Based Geopolymers Russo, Raffaele Emanuele Santoni, Elisa Fattobene, Martina Giovini, Mattia Genua, Francesco Leonelli, Cristina Lancellotti, Isabella Herrero Gutiérrez, Ana Berrettoni, Mario Alkali activation Metakaolin-based geopolymer Chromium salts Nickel salts Heavy metal stabilization Multivariate approach Design of experiments Principal component analysis Metales pesados Polímeros Heavy metals Polymers Alkali-activated aluminosilicate matrices are increasingly studied for their ability to stabilize hazardous metal contaminants via alkali activation at room temperature. In this study, metakaolin-based geopolymers were used to immobilize chromium and nickel salts, with systematic variation of key synthesis parameters, Na/Al molar ratio, metal concentration, anion type, and alkaline solution aging time, which have not been previously studied. A Design of Experiments approach was employed to study the effect of factors on metal leaching behavior and to better understand the underlying immobilization mechanisms. The analysis revealed that higher Na/Al ratios significantly enhance geopolymerization and reduce metal release, as supported by FTIR spectral shifts and decreased shoulder intensity. Notably, aging time had an influence on chromium behavior due to its effect on early silicate network formation, which can hinder the incorporation of chromium species. All tested formulations achieved metal immobilization rates of 98.8% or higher for both chromium and nickel. Overall, this study advances our understanding of geopolymer-based heavy metal immobilization. This research was funded by PNRR Next Generation UE, Mission 4, Component 2, Investment 1.1, D.D. N. 104 MUR 02/02/2022, and PRIN 2022 ACCHA-Advanced Chemical Characterization of Heavy Metals and Anions Encapsulated in Geopolymers with Synthetic Redox Environment, grant number 2022LKEKJ7, CUPE53D23008480006. 2025-09-11T11:19:14Z 2025-09-11T11:19:14Z 2025-08 info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion 1420-3049 https://hdl.handle.net/10259/10860 10.3390/molecules30153235 1420-3049 eng Molecules. 2025, V. 30, n. 15, 3235 https://doi.org/10.3390/molecules30153235 Atribución 4.0 Internacional http://creativecommons.org/licenses/by/4.0/ info:eu-repo/semantics/openAccess application/pdf MDPI https://riubu.ubu.es/bitstream/10259/10860/4/Russo_molecules_2025.pdf.jpg Hispana TEXT http://creativecommons.org/licenses/by/4.0/ RIUBU. Repositorio Institucional de la Universidad de Burgos https://hdl.handle.net/10259/10860