Synthesis and Characterization of Biochar-Based Geopolymer Materials

Piccolo, Federica; Andreola, F.; Barbieri, Luisa; Lancellotti, Isabella

doi:10.3390/app112210945

Cited by 13 publications

(8 citation statements)

References 45 publications

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“…The study [ 37 ] analysed the effect of NaOH concentration (6–14 M) on the mechanical properties of kaolin geopolymers. Compressive strength results showed that the optimum NaOH concentration is 8 M. Moreover, according to research results [ 3 , 4 , 11 , 12 , 13 , 14 , 16 , 17 , 18 , 19 , 37 , 38 , 39 , 40 , 42 , 43 ], the soluble glass to 8 M of NaOH solution ratio should be around 2.5 to give geopolymers high compressive strength [ 37 , 40 ]. Therefore, such recommendations were adopted to design the ratio of the alkaline solution in the analysed studies.…”

Section: Methodsmentioning

confidence: 99%

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The Comparison of the Environmental Impact of Waste Mineral Wool and Mineral in Wool-Based Geopolymer

Łaźniewska-Piekarczyk

Czop

Smyczek

2022

Materials

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Waste generated in fine wool production is homogeneous and without contamination, which increases its chances of reuse. Waste mineral wool from demolition sites belongs to the specific group of waste. However, the storage and collection require implementing restrictive conditions, such as improper storage of mineral wool, which is highly hazardous for the environment. The study focuses on the leachability of selected pollutants (pH, Cl−, SO42−) and heavy metals (Ba, Co, Cr, Cu, Ni, Pb, Zn) from the waste mineral wool. As a solution to the problem of storing mineral wool waste, it was proposed to process it into wool-based geopolymer. The geopolymer, based on mineral wool, was also assessed regarding the leaching of selected impurities. Rock mineral wool is very good for geopolymerisation, but the glass wool needs to be completed with additional components rich in Al2O3. The research involved geopolymer prepared from mineral glass wool with bauxite and Al2O3. So far, glass wool with the mentioned additives has not been tested. An essential aspect of the article is checking the influence of wool-based geopolymer on the environment. To investigate the environmental effects of the wool-based monolith and crushed wool geopolymers were compared. Such research has not been conducted so far. For this purpose, water extracts from fragmented geopolymers were made, and tests were carried out following EN 12457-4. There is no information in the literature on the influence of geopolymer on the environment, which is an essential aspect of its possible use. The research results proved that the geopolymer made on the base of mineral wool meets the environmental requirements, except for the pH value. As mentioned in the article, the geopolymerisation process requires the dissolution of the starting material in a high pH (alkaline) solution. On the other hand, the pH minimum 11.2 value of fresh geopolymer binder is required to start geopolymerisation. Moreover, research results analysed in the literature showed that the optimum NaOH concentration is 8 M. for the highest compressive strength of geopolymer. Therefore, the geopolymer strength decreases with NaO concentration in the NaOH solution. Geopolymers glass wool-based mortars with Al2O3 obtained an average compressive strength of 59, the geopolymer with bauxite achieved about 51 MPa. Thus, Al2O3 is a better additional glass wool-based geopolymer than bauxite. The average compressive strength of rock wool-based geopolymer mortar was about 62 MPa. The average compressive strength of wool-based geopolymer binder was about 20–25 MPa. It was observed that samples of geopolymers grout without aggregate participation are characterised by cracking and deformation.

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Section: Methodsmentioning

confidence: 99%

“…If the geopolymer is foamed in the production process, it might become lightweight and partly insulating [ 6 , 36 ]. On the other hand, in an almost pore-free form, the geopolymer may be used to protect walls against moisture and fungi formation [ 37 , 38 , 39 ].…”

Section: Introductionmentioning

confidence: 99%

The Comparison of the Environmental Impact of Waste Mineral Wool and Mineral in Wool-Based Geopolymer

Łaźniewska-Piekarczyk

Czop

Smyczek

2022

Materials

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“…However, the recovery process is regarded as unsuccessful for particles smaller than 8 mm [13]. The presence of metallic aluminum affects the mechanical behaviour of AABs, since it leads to a porosity increase due to the generation of hydrogen gas from the reaction between aluminum contained in IBA and the alkaline activators [36]. In contrast, the coarser fractions of IBAs are richer in glass (cullet) from containers and there is greater availability of SiO 2 for gelation reactions [13,19].…”

Section: Introductionmentioning

confidence: 99%

Effect of Temperature and Humidity on the Synthesis of Alkali-Activated Binders Based on Bottom Ash from Municipal Waste Incineration

et al. 2022

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Weathered bottom ash (WBA) from municipal solid waste incineration is a calcium aluminosilicate-rich material mainly used in construction and civil engineering as a secondary aggregate. However, its use is also being considered as a precursor in the manufacture of alkali-activated binders (AA-WBA). This preliminary research aimed to deepen understanding of the potential use of WBA (>8 mm fraction) as the sole precursor of alkali-activated binders. To gain better knowledge of this material, the physicochemical, mechanical, and environmental properties of AA-WBA binders were evaluated. In addition, the effect of curing temperature (25 °C, 45 °C, 65 °C, and 85 °C) and humidity conditions (oven and climate chamber) were assessed. The results of this study revealed that temperature and humidity conditions play a fundamental role during the early formation stages of AA-WBA binders. Maximum compactness and compressive strength (29.8 MPa) were obtained in the sample cured at 65 °C in the oven and room humidity. At higher temperatures (85 °C), a substantial decrease in mechanical strength (21.2 MPa) was observed due to a lower cohesion of the binder phases. Curing in the climate chamber led to an increase in humidity, and therefore a decrease in compressive strength. Finally, lower porosity and longer curing time substantially decreased the heavy metals and metalloid leaching concentration of AA-WBA binders.

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“…Salas et al [7] scaled the introduction of large amounts of industrial inorganic into fired clay cycles up to industrial production without significantly altering the technical properties of products. Furthermore, Piccolo et al [8] developed AAM-exploiting biochar, a secondary raw material coming from pyrolysis/gasification processes, for the improvement of soil fertility and reduction of CO 2 emissions because of the carbon sink process. Because of the promising technical results obtained, the AAM can be used for insulating panels or lightweight materials for houses and gardens in terraces and balconies.…”

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confidence: 99%