Novel porous fly ash-containing geopolymers for pH buffering applications

Novais, Rui M.; Buruberri, L.H.; Seabra, M.P.; Bajāre, Diāna; Labrincha, J.A.

doi:10.1016/j.jclepro.2016.02.114

Cited by 76 publications

(34 citation statements)

References 30 publications

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“…For instance, during wastewater sludge biogasification, a significant pH drop can occur due to the formation of acids by bacteria metabolism, making maintaining a constant pH challenging. AAMs are potential pH buffering materials as they contain free leachable alkalis in pore solution (Lloyd et al 2010; Bumanis and Bajare 2014; Bumanis 2015; Ascensão et al 2017;Novais et al 2016aNovais et al , 2017.…”

Section: Applications In Water and Wastewater Treatmentmentioning

confidence: 99%

Application of alkali-activated materials for water and wastewater treatment: a review

Luukkonen

Heponiemi

Runtti

et al. 2019

Rev Environ Sci Biotechnol

128

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Alkali-activation (or geopolymer) technology has gained a great deal of interest for its potential applications in water and wastewater treatment during the last decade. Alkali-activated materials can be prepared via a relatively simple and low-energy process, most commonly by treating aluminosilicate precursors with concentrated alkali hydroxide and/or silicate solutions at (near) ambient conditions. The resulting materials are, in general, amorphous, have good physical and chemical stability, ion-exchange properties, and a porous structure. Several of the precursors are industrial by-products or other readily available low-cost materials, which further enhances the environmental and economic feasibility. The application areas of alkali-activated materials in water and wastewater treatment are adsorbents/ion-exchangers, photocatalysts, high-pressure membranes, filter media, anti-microbial materials, pH buffers, carrier media in bioreactors, and solidification/stabilization of water treatment residues. The purpose of this review is to present a comprehensive evaluation of the rapidly growing prospects of alkali-activation technology in water and wastewater treatment.

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Section: Applications In Water and Wastewater Treatmentmentioning

confidence: 99%

Application of alkali-activated materials for water and wastewater treatment: a review

Luukkonen

Heponiemi

Runtti

et al. 2019

Rev Environ Sci Biotechnol

128

View full text Add to dashboard Cite

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“…The same authors also reported the development of other alkali activated materials with long-term stable leaching properties (pH fluctuation below 1.0 over 25 d of immersion in deionised water). However, their production requires an energy intense synthesis process, which involves a thermal treatment up to 400 C. Fly-ash containing geopolymers with prolonged alkalis leaching properties have been reported, being the leaching properties mainly associated to the solid-liquid ratio and to the pore forming agent content (Novais et al, 2016d). The low Na 2 O content on the used ashes demand highly concentrated NaOH solutions to increase the total Na 2 O concentration, thus assuring high alkali diffusiveness.…”

Section: Geopolymers Characterizationmentioning

confidence: 99%

Red mud-based geopolymers with tailored alkali diffusion properties and pH buffering ability

Ascensão

Seabra

Aguiar

et al. 2017

Journal of Cleaner Production

104

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This study develop novel porous red mud (RM) based geopolymers and evaluates their potential to ensure prolonged pH control. Several properties of the novel geopolymers were examined including buffering ability, alkalis leaching behaviour, mineralogical composition, microstructure and physical properties. Two experimental plans were defined to evaluate the influence of porosity and RM content on those properties. The pH values of the eluted water and geopolymers OH À ions leaching have been determined over time showing that total OH À ions and the leaching rate can be tailored by controlling the geopolymers porous structure and the availability of free alkaline species. The lower pH gradient over 28th d (1.64 pH units) was achieved by combining a 0.025 wt% pore forming agent (aluminium powder) with 45 wt% MK replacement by red mud. A high and prolonged buffer capacity was accomplished, proving that red mud-based geopolymers have potential to be applied as pH buffering material.

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“…Traditionally, alkalizing agents, such as lime or caustic soda, have been employed to increase the pH levels, which induce chemical clarification of wastewaters [1]. However, more recently, some papers have been published in which the idea of using low-calcium, alkali-activated materials (AAM) for this purpose has also been considered with some promising results [2][3][4][5][6].…”

Section: Introductionmentioning

confidence: 99%

Low-Calcium, Porous, Alkali-Activated Materials as Novel pH Stabilizers for Water Media

et al. 2020

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Due to the increase of water consumption, water treatment systems become more actual and innovative materials for water treatment are welcomed. Traditionally, alkalizing agents, such as lime or caustic soda, have been employed to increase the pH levels, which induce chemical clarification of wastewater. Some innovative ideas of using low-calcium, alkali-activated materials (AAM) for this purpose have been considered previously. In this study, the low-calcium, porous, alkali-activated material (pAAM) was characterized to understand the impact of the aluminum silicate source and heat treatment on basic properties for material that might be used in water treatment systems as a softener by stabilizing the pH. The studied porous alkali-activated materials may ensure stable and long-lasting (30 days) pH (pH 10.3–11.6) in water media depending on the composition and amount of activation solution used for AAM preparation. Heat treatment does not have an impact on the mineralogical composition and structural properties of the pAAM, but it does change the leaching ability of alkalis from the material structure.

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Novel porous fly ash-containing geopolymers for pH buffering applications

Cited by 76 publications

References 30 publications

Application of alkali-activated materials for water and wastewater treatment: a review

Application of alkali-activated materials for water and wastewater treatment: a review

Red mud-based geopolymers with tailored alkali diffusion properties and pH buffering ability

Low-Calcium, Porous, Alkali-Activated Materials as Novel pH Stabilizers for Water Media

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