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Development of Paper Sludge Ash-Based Geopolymer and Application to Treatment of Hazardous Water Contaminated with Radioisotopes

Ambient temperature geopolymerization of paper sludge ashes (PS-ashes) discharged from paper mills was studied by means of scanning electron microscopy (SEM), X-ray diffraction (XRD), induction coupled plasma atomic emission spectrometry (ICP-AES), and X-ray absorption near edge structure (XANES). T...

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Autores principales: Li, Zhuguo, Ohnuki, Toshihiko, Ikeda, Ko
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2016
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5509079/
https://www.ncbi.nlm.nih.gov/pubmed/28773754
http://dx.doi.org/10.3390/ma9080633
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author Li, Zhuguo
Ohnuki, Toshihiko
Ikeda, Ko
author_facet Li, Zhuguo
Ohnuki, Toshihiko
Ikeda, Ko
author_sort Li, Zhuguo
collection PubMed
description Ambient temperature geopolymerization of paper sludge ashes (PS-ashes) discharged from paper mills was studied by means of scanning electron microscopy (SEM), X-ray diffraction (XRD), induction coupled plasma atomic emission spectrometry (ICP-AES), and X-ray absorption near edge structure (XANES). Two varieties of alkaline liquors were used in the PS-ash based geopolymers, corresponding to aqueous Na-metasilicate and Na-disilicate compositions. PS-ashes were found to be semi-crystalline and to have porous structures that make it possible to absorb much liquor. Flexural strengths of PS-ash-based geopolymers with liquor/filler ratios (L/F) of 1.0–1.5 ranged from 0.82 to 1.51 MPa at 4 weeks age, depending on PS-ashes and liquors used. The reaction process of the constituent minerals of the PS-ash is discussed. Furthermore, we attempted to solidify hazardous water contaminated with radioisotopes. Non-radioactive strontium and cesium nitrates were added as surrogates at a dosage of 1% into the PS-ash-based geopolymers. Generally, high immobilization ratios up to 99.89% and 98.77% were achieved for Sr(2+) and Cs(+), respectively, depending on the source of PS-ashes, alkaline liquors, and material ages. However, in some cases, poor immobilization ratios were encountered, and we further discussed the causes of the instability of derived geopolymer gels on the basis of XANES spectra.
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spelling pubmed-55090792017-07-28 Development of Paper Sludge Ash-Based Geopolymer and Application to Treatment of Hazardous Water Contaminated with Radioisotopes Li, Zhuguo Ohnuki, Toshihiko Ikeda, Ko Materials (Basel) Article Ambient temperature geopolymerization of paper sludge ashes (PS-ashes) discharged from paper mills was studied by means of scanning electron microscopy (SEM), X-ray diffraction (XRD), induction coupled plasma atomic emission spectrometry (ICP-AES), and X-ray absorption near edge structure (XANES). Two varieties of alkaline liquors were used in the PS-ash based geopolymers, corresponding to aqueous Na-metasilicate and Na-disilicate compositions. PS-ashes were found to be semi-crystalline and to have porous structures that make it possible to absorb much liquor. Flexural strengths of PS-ash-based geopolymers with liquor/filler ratios (L/F) of 1.0–1.5 ranged from 0.82 to 1.51 MPa at 4 weeks age, depending on PS-ashes and liquors used. The reaction process of the constituent minerals of the PS-ash is discussed. Furthermore, we attempted to solidify hazardous water contaminated with radioisotopes. Non-radioactive strontium and cesium nitrates were added as surrogates at a dosage of 1% into the PS-ash-based geopolymers. Generally, high immobilization ratios up to 99.89% and 98.77% were achieved for Sr(2+) and Cs(+), respectively, depending on the source of PS-ashes, alkaline liquors, and material ages. However, in some cases, poor immobilization ratios were encountered, and we further discussed the causes of the instability of derived geopolymer gels on the basis of XANES spectra. MDPI 2016-07-28 /pmc/articles/PMC5509079/ /pubmed/28773754 http://dx.doi.org/10.3390/ma9080633 Text en © 2016 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC-BY) license (http://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Li, Zhuguo
Ohnuki, Toshihiko
Ikeda, Ko
Development of Paper Sludge Ash-Based Geopolymer and Application to Treatment of Hazardous Water Contaminated with Radioisotopes
title Development of Paper Sludge Ash-Based Geopolymer and Application to Treatment of Hazardous Water Contaminated with Radioisotopes
title_full Development of Paper Sludge Ash-Based Geopolymer and Application to Treatment of Hazardous Water Contaminated with Radioisotopes
title_fullStr Development of Paper Sludge Ash-Based Geopolymer and Application to Treatment of Hazardous Water Contaminated with Radioisotopes
title_full_unstemmed Development of Paper Sludge Ash-Based Geopolymer and Application to Treatment of Hazardous Water Contaminated with Radioisotopes
title_short Development of Paper Sludge Ash-Based Geopolymer and Application to Treatment of Hazardous Water Contaminated with Radioisotopes
title_sort development of paper sludge ash-based geopolymer and application to treatment of hazardous water contaminated with radioisotopes
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5509079/
https://www.ncbi.nlm.nih.gov/pubmed/28773754
http://dx.doi.org/10.3390/ma9080633
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