Utilizing metakaolin and siliceous waste from the alum industry to create geopolymer adsorbent for the removal of certain heavy metals

Abstract A geopolymer (GP) from Partially Dealuminated Kaolin (PDK) was synthesized. PDK is a solid waste of alum industry, it was produced in a big quantity, which need careful management to be recycled for protection of the environment against pollution. Utilization of PDK is very lacking, and the...

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Main Authors: Khaled Elewa, A. F. Tawfic, Mostafa Tarek, Nabil Abdullah Al-Sagheer, Nabil M. Nagy
Format: Article
Language:English
Published: Nature Portfolio 2025-07-01
Series:Scientific Reports
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Online Access:https://doi.org/10.1038/s41598-025-10800-w
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author Khaled Elewa
A. F. Tawfic
Mostafa Tarek
Nabil Abdullah Al-Sagheer
Nabil M. Nagy
author_facet Khaled Elewa
A. F. Tawfic
Mostafa Tarek
Nabil Abdullah Al-Sagheer
Nabil M. Nagy
author_sort Khaled Elewa
collection DOAJ
description Abstract A geopolymer (GP) from Partially Dealuminated Kaolin (PDK) was synthesized. PDK is a solid waste of alum industry, it was produced in a big quantity, which need careful management to be recycled for protection of the environment against pollution. Utilization of PDK is very lacking, and there were no studies for using in the preparation of geopolymer as an adsorbent for heavy metal removal from wastewater. GP was used for the removal of Cr, Cd, and Pb from synthetic industrial wastewater by the adsorption technique. FTIR spectrum indicates a peak at 977 cm−1 due to Si–O–Si and Si–O–Al bonds confirming the formation of geopolymer. The effects of various parameters such as temperature, pH, contact time, and metal ion concentration were tested to stand over the most favorable conditions for adsorption. A total of 100% removal was achieved at a pH = 6.0, temperature = 25 °C, and initial concentration = 40 mg/L for a contact time of 60 min using a dosage of 0.2 g/L. The adsorption data validated Freundlich adsorption model. The values of Freundlich constant value, R2 were greater than 0.99 indicating the adsorption of metal ions onto the geopolymer to be highly favorable. High adsorption capacity has been achieved for Pb, Cd, and Cr (105.6 mg/g for Pb, 150 mg/g for Cd, 125 mg/g for Cr). The adsorption process followed pseudo-1st-order kinetics yielding high correlation coefficient and the adsorbed amount at equilibrium. More than 95% of adsorption was achieved at room temperature supports the effectiveness of metal ions adsorption on the geopolymer. This work helps for the reuse of the industrial waste of alum industry through the synthesis of a geopolymeric adsorbent, which can be applied successfully for removal of the Pb, Cd, and Cr ions from the polluted water.
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issn 2045-2322
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spelling doaj-art-cce512db738448f9a47d954488bfda3b2025-08-20T04:01:51ZengNature PortfolioScientific Reports2045-23222025-07-0115111510.1038/s41598-025-10800-wUtilizing metakaolin and siliceous waste from the alum industry to create geopolymer adsorbent for the removal of certain heavy metalsKhaled Elewa0A. F. Tawfic1Mostafa Tarek2Nabil Abdullah Al-Sagheer3Nabil M. Nagy4Civil Engineering Department, Military Technical CollegeHead of Nuclear Engineering Department, Military Technical CollegeCivil Engineering Department, Military Technical CollegeAluminum Sulfate Co. of EgyptCivil Engineering Department, Military Technical CollegeAbstract A geopolymer (GP) from Partially Dealuminated Kaolin (PDK) was synthesized. PDK is a solid waste of alum industry, it was produced in a big quantity, which need careful management to be recycled for protection of the environment against pollution. Utilization of PDK is very lacking, and there were no studies for using in the preparation of geopolymer as an adsorbent for heavy metal removal from wastewater. GP was used for the removal of Cr, Cd, and Pb from synthetic industrial wastewater by the adsorption technique. FTIR spectrum indicates a peak at 977 cm−1 due to Si–O–Si and Si–O–Al bonds confirming the formation of geopolymer. The effects of various parameters such as temperature, pH, contact time, and metal ion concentration were tested to stand over the most favorable conditions for adsorption. A total of 100% removal was achieved at a pH = 6.0, temperature = 25 °C, and initial concentration = 40 mg/L for a contact time of 60 min using a dosage of 0.2 g/L. The adsorption data validated Freundlich adsorption model. The values of Freundlich constant value, R2 were greater than 0.99 indicating the adsorption of metal ions onto the geopolymer to be highly favorable. High adsorption capacity has been achieved for Pb, Cd, and Cr (105.6 mg/g for Pb, 150 mg/g for Cd, 125 mg/g for Cr). The adsorption process followed pseudo-1st-order kinetics yielding high correlation coefficient and the adsorbed amount at equilibrium. More than 95% of adsorption was achieved at room temperature supports the effectiveness of metal ions adsorption on the geopolymer. This work helps for the reuse of the industrial waste of alum industry through the synthesis of a geopolymeric adsorbent, which can be applied successfully for removal of the Pb, Cd, and Cr ions from the polluted water.https://doi.org/10.1038/s41598-025-10800-wAdsorptionAluminum sulfate residueGeopolymerHeavy metal removalMetakaolinWater treatment
spellingShingle Khaled Elewa
A. F. Tawfic
Mostafa Tarek
Nabil Abdullah Al-Sagheer
Nabil M. Nagy
Utilizing metakaolin and siliceous waste from the alum industry to create geopolymer adsorbent for the removal of certain heavy metals
Scientific Reports
Adsorption
Aluminum sulfate residue
Geopolymer
Heavy metal removal
Metakaolin
Water treatment
title Utilizing metakaolin and siliceous waste from the alum industry to create geopolymer adsorbent for the removal of certain heavy metals
title_full Utilizing metakaolin and siliceous waste from the alum industry to create geopolymer adsorbent for the removal of certain heavy metals
title_fullStr Utilizing metakaolin and siliceous waste from the alum industry to create geopolymer adsorbent for the removal of certain heavy metals
title_full_unstemmed Utilizing metakaolin and siliceous waste from the alum industry to create geopolymer adsorbent for the removal of certain heavy metals
title_short Utilizing metakaolin and siliceous waste from the alum industry to create geopolymer adsorbent for the removal of certain heavy metals
title_sort utilizing metakaolin and siliceous waste from the alum industry to create geopolymer adsorbent for the removal of certain heavy metals
topic Adsorption
Aluminum sulfate residue
Geopolymer
Heavy metal removal
Metakaolin
Water treatment
url https://doi.org/10.1038/s41598-025-10800-w
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