Porous and reusable potassium-activated geopolymer adsorbent with high compressive strength fabricated from coal fly ash wastes

Kaewmee, Patcharanat; Song, Mengzhu; Iwanami, Mitsuyasu; Tsutsumi, Hiroshi; Takahashi, Fumio

doi:10.1016/j.jclepro.2020.122617

Cited by 49 publications

(10 citation statements)

References 49 publications

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“…It involves the dissolution of aluminum silicate with geological origin substance or industrial waste such as slag, ash, biomass, or red mud in a highly alkaline medium releasing Si and Al species [19]. Numerous studies have elaborated on the geopolymeric formation by the utilization of incinerated municipal solid waste (MSW) ash, namely municipal solid waste bottom ash (MSW-BA) and fly ash (MSW-FA) as a source of solid aluminosilicate [20][21][22][23][24][25]. The composition of the geopolymers consists of a three-dimensional network of free AlO 4 and SiO 4 tetrahedral, which are formed due to the breakdown of Si-O-Si and Si-O-Al bonds.…”

Section: Introductionmentioning

confidence: 99%

Application of geopolymers synthesized from incinerated municipal solid waste ashes for the removal of cationic dye from water

et al. 2020

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In this study, municipal solid waste bottom ash (MSW-BA) and fly ash (MSW-FA) were used as a source of aluminosilicate to prepare geopolymer (GEO) adsorbents (GEO-MSWBA and GEO-MSWFA) for the removal of methylene blue (MB) from water. The effects of temperature, pH, and initial concentration on the MB adsorption onto GEO-MSWBA and GEO-MSWFA were evaluated. The adsorption isotherms parameters and thermodynamics were also determined. Detailed physical and chemical characterizations of the prepared adsorbents were carried out to further understand their impact on MB adsorption. The results from the scanning electron microscopy revealed a uniform granule-sphere like structure on both prepared geopolymers, which would facilitate the MB adsorption onto the adsorbents. The X-ray diffraction allowed observation of the microstructural transformations that occur after the alkaline activation. The surface areas of the GEO-MSWBA and the GEO-MSWFA were recorded as 32.78 m2/g and 4.5 m2/g, respectively. From the Fourier transform infrared, a stretching vibration of the aluminosilicate tetrahedral was observed, which indicated the success of geopolymerization. The prepared geopolymers showed a high capability of MB adsorption from an aqueous solution. The adsorption process was best suited and explained using the Langmuir isotherm model with a maximum adsorption capacity of 666.7 mg/g for the GEO-MSWBA (at 25°C) and 769.2 mg/g for the GEO-MSWFA (at 35°C). The positive value of the enthalpy (ΔHo) for the GEO-MSWBA suggested the reaction favored endothermic reaction while the negative value of entropy (ΔSo) indicated a solid/liquid random interaction. On the other hand, the negative ΔHo value for the GEO-MSWFA indicated the reaction followed an exothermic reaction causing energy to be released, the positive ΔSo value indicated a good affinity at the solid-liquid surface. The overall negative value for Gibbs free energy (ΔGo) for both adsorbents suggested the adsorption was spontaneous and feasible. It was also inferred that n- π interaction, direct and indirect hydrogen bond, and electrostatic interaction between the MB and the prepared geopolymers facilitated the adsorption process. The current study shows that the GEO-MSWBA and the GEO-MSWFA have a great potential of removing MB as a cationic dye from water without performing any sort of laborious pretreatments.

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Section: Introductionmentioning

confidence: 99%

Application of geopolymers synthesized from incinerated municipal solid waste ashes for the removal of cationic dye from water

et al. 2020

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“…Although regenerability has not been covered in this study, a few previous studies have shown that a geopolymer-based adsorbent can be made regenerable with appropriate design and fabrication. − …”

Section: Results and Discussionmentioning

confidence: 99%

Examining the Effect of a Chitosan Biopolymer on Alkali-Activated Inorganic Material for Aqueous Pb(II) and Zn(II) Sorption

Mondal

Nwadire

et al. 2022

Langmuir

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Biopolymers and alkali-activated materials have attracted a great deal of attention as adsorbents for the removal of heavy metal contaminants from aqueous solutions. Both materials are sustainable and feature unique properties, but biopolymers are relatively more expensive or difficult to prepare and exhibit low mechanical and surface properties, a narrow pH range, and thermal stability. In this study, hybrid adsorbents were prepared from both types of material, by alkali activation of low-cost fly ash precursors accompanied by incorporation of 0–2%mass chitosan biopolymer. Two types of alkaline activating solutions, NaOH and Na2SiO3, were employed to generate two sets of hybrid adsorbents with varying chitosan contents. The effect of the chitosan dosage on the aqueous Pb(II) and Zn(II) sorption efficiency was also investigated. The adsorbents exhibited 98–100% removal efficiencies for both metals, but the sorption of Zn(II) was generally higher than that of Pb(II). The addition of 0.1–2.0%mass chitosan resulted in very little improvement in the overall efficiency of the adsorbents. In contrast, 0.05%mass chitosan led to a decrease in the sorption efficiency; this was linked to the decrease in the adsorbents’ ζ potential. The Na2SiO3-activated materials featured larger BET surface areas and better overall sorption performance, while the NaOH-activated materials showed the worst Pb(II) sorption performance and hence more noticeable improvement upon addition of chitosan. Mechanistic investigation shows that the sorption process follows second-order kinetics and is a chemisorption-driven process.

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“…SEM was used to analyse the GGPC mixes microstructure to understand the influences of LCWWA. The figures revealed the different gel formations (Wang et al , 2020) due to the geopolymerization reaction, namely, sodium silicate hydrate (Na-S-H) gel (Cheah et al , 2017; Xiao et al , 2020), potassium silicate hydrate (K-S-H) gel (Cheah et al , 2017; Kaewmee et al , 2020) and calcium silicate hydrate (C-S-H) gel (Cheah et al , 2017). A residual solvent (Ban and Ramli, 2012) was noted in the mix GGPC 3 with fractured and heterogeneous matrix (Cheah and Ramli, 2012).…”

Section: Resultsmentioning

confidence: 99%

Invention of sustainable geopolymer concrete made with low calcium waste wood ash

Arunkumar

Muthukannan

Kumar

et al. 2021

WJE

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Purpose Inefficient waste disposal technique and cement production methodology caused significant environmental impacts, leading to global warming. The purpose of the research was to invent an effective, sustainable technology to use the wastes and alternate for cement in concrete. Geopolymer technology could be the most desirable solution to use the wastes into an effective product. Design/methodology/approach The wood waste ash derived from nearby tea shops was used as an alternate binder for fly ash. The replacement of WWA with FA was varied from 0 to 100% at 10% intervals. In this research, setting and mechanical features of Geopolymer Concrete (GPC) along with Waste wood ash (WWA) was carried out. The influence of wood waste ash in the microstructure of the GPC was also assessed using scanning electron microscope and X-ray diffraction analysis. Findings The findings revealed that 30% replacement of wood waste ash was performed higher in all measured features. Besides, the formation of different phases was also observed with the inclusion of wood waste ash. Research limitations/implications The demand for fly ash was increased in recent years, and the fly-based GPC has required more alkaline solution and temperature curing. Hence, there was a research gap on finding an alternative binder for fly ash. Originality/value The research novelty was to use the wood waste ash, which has inbuilt alkaline compounds on the production of sustainable geopolymer. The finding showed that the wood waste ash could be alternate fly ash that eliminates the environmental impacts and economic thrust.

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Porous and reusable potassium-activated geopolymer adsorbent with high compressive strength fabricated from coal fly ash wastes

Cited by 49 publications

References 49 publications

Application of geopolymers synthesized from incinerated municipal solid waste ashes for the removal of cationic dye from water

Application of geopolymers synthesized from incinerated municipal solid waste ashes for the removal of cationic dye from water

Examining the Effect of a Chitosan Biopolymer on Alkali-Activated Inorganic Material for Aqueous Pb(II) and Zn(II) Sorption

Invention of sustainable geopolymer concrete made with low calcium waste wood ash

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