Design of Experiments Approach for Efficient Heavy Metals Stabilization Using Metakaolin-Based Geopolymers
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 sy...
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MDPI AG
2025-08-01
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| Series: | Molecules |
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| Online Access: | https://www.mdpi.com/1420-3049/30/15/3235 |
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| author | Raffaele Emanuele Russo Elisa Santoni Martina Fattobene Mattia Giovini Francesco Genua Cristina Leonelli Isabella Lancellotti Ana Herrero Mario Berrettoni |
| author_facet | Raffaele Emanuele Russo Elisa Santoni Martina Fattobene Mattia Giovini Francesco Genua Cristina Leonelli Isabella Lancellotti Ana Herrero Mario Berrettoni |
| author_sort | Raffaele Emanuele Russo |
| collection | DOAJ |
| description | 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. |
| format | Article |
| id | doaj-art-03d3e2d2978e475f85bd597f35a117ec |
| institution | Kabale University |
| issn | 1420-3049 |
| language | English |
| publishDate | 2025-08-01 |
| publisher | MDPI AG |
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| series | Molecules |
| spelling | doaj-art-03d3e2d2978e475f85bd597f35a117ec2025-08-20T03:36:32ZengMDPI AGMolecules1420-30492025-08-013015323510.3390/molecules30153235Design of Experiments Approach for Efficient Heavy Metals Stabilization Using Metakaolin-Based GeopolymersRaffaele Emanuele Russo0Elisa Santoni1Martina Fattobene2Mattia Giovini3Francesco Genua4Cristina Leonelli5Isabella Lancellotti6Ana Herrero7Mario Berrettoni8School of Science and Technology, Chemistry Division, University of Camerino, Via Madonna delle Carceri—ChIP, 62032 Camerino, MC, ItalySchool of Science and Technology, Chemistry Division, University of Camerino, Via Madonna delle Carceri—ChIP, 62032 Camerino, MC, ItalySchool of Science and Technology, Chemistry Division, University of Camerino, Via Madonna delle Carceri—ChIP, 62032 Camerino, MC, ItalyDepartment of Engineering “Enzo Ferrari”, University of Modena and Reggio Emilia, Via P. Vivarelli n. 10, 41125 Modena, MO, ItalyDepartment of Engineering “Enzo Ferrari”, University of Modena and Reggio Emilia, Via P. Vivarelli n. 10, 41125 Modena, MO, ItalyDepartment of Engineering “Enzo Ferrari”, University of Modena and Reggio Emilia, Via P. Vivarelli n. 10, 41125 Modena, MO, ItalyDepartment of Engineering “Enzo Ferrari”, University of Modena and Reggio Emilia, Via P. Vivarelli n. 10, 41125 Modena, MO, ItalyDepartment of Chemistry, Faculty of Sciences, Universidad de Burgos, Plaza Misael Bañuelos s/n, 09001 Burgos, SpainSchool of Science and Technology, Chemistry Division, University of Camerino, Via Madonna delle Carceri—ChIP, 62032 Camerino, MC, ItalyAlkali-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.https://www.mdpi.com/1420-3049/30/15/3235alkali activationmetakaolin-based geopolymerchromium saltsnickel saltsheavy metal stabilizationmultivariate approach |
| spellingShingle | Raffaele Emanuele Russo Elisa Santoni Martina Fattobene Mattia Giovini Francesco Genua Cristina Leonelli Isabella Lancellotti Ana Herrero Mario Berrettoni Design of Experiments Approach for Efficient Heavy Metals Stabilization Using Metakaolin-Based Geopolymers Molecules alkali activation metakaolin-based geopolymer chromium salts nickel salts heavy metal stabilization multivariate approach |
| title | Design of Experiments Approach for Efficient Heavy Metals Stabilization Using Metakaolin-Based Geopolymers |
| title_full | Design of Experiments Approach for Efficient Heavy Metals Stabilization Using Metakaolin-Based Geopolymers |
| title_fullStr | Design of Experiments Approach for Efficient Heavy Metals Stabilization Using Metakaolin-Based Geopolymers |
| title_full_unstemmed | Design of Experiments Approach for Efficient Heavy Metals Stabilization Using Metakaolin-Based Geopolymers |
| title_short | Design of Experiments Approach for Efficient Heavy Metals Stabilization Using Metakaolin-Based Geopolymers |
| title_sort | design of experiments approach for efficient heavy metals stabilization using metakaolin based geopolymers |
| topic | alkali activation metakaolin-based geopolymer chromium salts nickel salts heavy metal stabilization multivariate approach |
| url | https://www.mdpi.com/1420-3049/30/15/3235 |
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