Synthesis of Zeolites from Fine-Grained Perlite and Their Application as Sorbents

Painer, Florian; Baldermann, Andre; Gallien, Florian; Eichinger, Stefanie; Steindl, Florian Roman; Dohrmann, R.; Dietzel, Martin

doi:10.3390/ma15134474

Cited by 6 publications

(6 citation statements)

References 66 publications

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“…The analytical error was determined to be ±0.5 wt % for the major elements based on replicate analyses of USGS standards. 33 To determine the specific surface area (SSA) of the MgO raw materials, five-point adsorption measurements with nitrogen (N 2 ) gas were performed according to the method of Brunauer, Emmett, and Teller (BET). A Micromeritics surface area analyzer VII 2390 was run at relative gas pressure ratios (p/p 0 ) from 0.05 to 0.35 with a sample of ≈0.5 g for each test.…”

Section: Methodsmentioning

confidence: 99%

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Hydration of MgO: Reaction Kinetics and pH Control on Brucite Crystal Morphology

Pettauer,

Baldermann,

Eder

et al. 2024

Crystal Growth & Design

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The hydration of periclase [MgO] to yield brucite [Mg(OH) 2 ] is of high relevance in many technical and man-made surroundings, regarding its volume expansive reaction and the development of distinct crystal morphologies. Although studies on the MgO−Mg(OH) 2 conversion behavior are numerous, the decisive parameters controlling its kinetics as well as the size, the shape, and the orientation of individual brucite crystals remain poorly constrained. Therefore, a series of MgO hydration experiments were conducted to monitor and assess the influence of the surface area and the presence of secondary phases in MgO educts on (i) the chemical evolution of the reactive solution, (ii) the MgO−Mg(OH) 2 conversion rate, and (iii) the development of the particle morphology of brucite. The reactive surface area of the MgO significantly stimulates the hydration and thus the conversion rate to yield brucite. In contrast, individual foreign components, such as CaO or MgCl 2 , within the MgO educts predefine the selfadjusting pH during progressing MgO hydration. The pH evolution regulates the charge distribution at the reacting MgO surface and thus has a key control on the morphology of the precipitating brucite crystals. Flaky versus columnar crystal shapes are formed preferentially below and above the point of zero charge of MgO and Mg(OH) 2 (pH PZC ≈ 11 to 12), respectively, which has implications for tailored product engineering.

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Section: Methodsmentioning

confidence: 99%

“…The XRF data were analyzed using IQ+ software (PANalytical). The analytical error was determined to be ±0.5 wt % for the major elements based on replicate analyses of USGS standards …”

Section: Methodsmentioning

confidence: 99%

Hydration of MgO: Reaction Kinetics and pH Control on Brucite Crystal Morphology

Pettauer,

Baldermann,

Eder

et al. 2024

Crystal Growth & Design

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“…Our results indicate that the Cu-GPs had a high resistance against Na + exchange (Figure 4), suggesting that the exchange processes with other Me ions are also limited. On the other hand, the porous geopolymer network may allow the sorption and/or incorporation of potentially other hazardous Me cations from solution given that these dissolved components have an identical ionic charge and a Me ionic radius similar to Cu 2+ , such as Co 2+ , Mn 2+ , nickel (Ni 2+ ), palladium (Pd 2+ ) and Zn 2+ [67]. However, the immobilization potential of such Me ions by GP has to be evaluated in future studies, with particular focus on nearneutral and acidic aqueous media where Me ion immobilization by GP is crucial.…”

Section: Implications For Water Treatment and Environmental Remediationmentioning

confidence: 99%

“…The type of binding of Cu 2+ ions in the three-dimensional molecular network of geopolymers is key for predicting their stability in corrosive systems. The behavior of Cu 2+ -containing low-Ca geopolymers is often viewed analogously to zeolite minerals [67], because of their apparent crystal-chemical similarities. Zeolites are scaffold silicates, consisting of cross-linked (Si,Al)O 4 tetrahedrons with Na + or K + ions occupying exchangeable sites to keep electrostatic neutrality.…”

Section: Implications For Water Treatment and Environmental Remediationmentioning

confidence: 99%

Substantial Copper (Cu2+) Uptake by Metakaolin-Based Geopolymer and Its Resistance to Acid Leaching and Ion Exchange

et al. 2023

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Geopolymers are inorganic, chemically resistant aluminosilicate-based binding agents, which remove hazardous metal ions from exposed aqueous media. However, the removal efficiency of a given metal ion and the potential ion remobilization have to be assessed for individual geopolymers. Therefore, copper ions (Cu2+) were removed by a granulated, metakaolin-based geopolymer (GP) in water matrices. Subsequent ion exchange and leaching tests were used to determine the mineralogical and chemical properties as well as the resistance of the Cu2+-bearing GPs to corrosive aquatic environments. Experimental results indicate the pH of the reacted solutions to have a significant impact on the Cu2+ uptake systematics: the removal efficiency ranged from 34–91% at pH 4.1–5.7 up to ~100% at pH 11.1–12.4. This is equivalent to Cu2+ uptake capacities of up to 193 mg/g and 560 mg/g in acidic versus alkaline media. The uptake mechanism was governed by Cu2+-substitution for alkalis in exchangeable GP sites and by co-precipitation of gerhardtite (Cu2(NO3)(OH)3) or tenorite (CuO) and spertiniite (Cu(OH)2). All Cu-GPs showed excellent resistance to ion exchange (Cu2+ release: 0–2.4%) and acid leaching (Cu2+ release: 0.2–0.7%), suggesting that tailored GPs have a high potential to immobilize Cu2+ ions from aquatic media.

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“…Agricultural crops absorb organic dyes from the soil, the dyes are transported from soils to plants and can inhibit root growth, damage root tips, lower the uptake of nutrients and water, reduce germination and photosynthetic pigments (Zhou, 2001 ). As only low levels of these dyes can be removed by the activated sludge process (Kandelbauer et al, 2007 ), when organic dyes (commonly, synthetic aromatic compounds) are to be removed from textile wastewater, adsorption is an inexpensive useful technique (Angelova et al, 2017 ; Bensalah, 2024 ; George et al, 2024 ; Khamis et al, 2024 ) and perlites (Mathew et al, 2018 ; Painer et al, 2022 ) are abundant, economically attractive adsorbents (Khoshraftar et al, 2023 ; Roulia & Vassiliadis, 2005 , 2008 ). Decolorized dyebath wastewaters (Roulia & Vassiliadis, 2021 ) with a nitrogen content reduced to acceptable levels meet the quality standards for surface and ground water and could effectively be applied to crops.…”

Section: Introductionmentioning

confidence: 99%

C.I. Acid Black 1 transfer from dilute solution to perlite framework in organic waste management

Roulia,

Vassiliadis

2024

Environ Geochem Health

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Dyes, considered as toxic and persistent pollutants, must be removed from organic wastes prior to their composting and application in sustainable agriculture. Azo dyes, capable of altering the physicochemical properties of soil, are difficult to expel by conventional wastewater treatments. C.I. Acid Black 1 (AB 1), a sulfonated azo dye, inhibits nitrification and ammonification in the soil, lessens the nitrogen use efficacy in crop production and passes substantially unaltered through an activated sludge process. The retention of C.I. Acid Black 1 by raw and expanded perlite was investigated in order to examine the potential effectiveness of this aluminosilicate material toward organic waste cleanup. Dye adsorption proved spontaneous and endothermic in nature, increasing with temperature for both perlites. Expanded perlite having a more open structure exhibited a better performance compared to the raw material. Several of the most widely recognized two-parameter theoretical models, i.e., Langmuir, Freundlich, Temkin, Brunauer–Emmett–Teller (BET), Harkins–Jura, Halsey, Henderson, and Smith, were applied to reveal physicochemical features characterizing the adsorption. The Langmuir, Freundlich, Temkin, BET, Henderson, and Smith equations best fitted experimental data indicating that the adsorption of anionic dye on perlites is controlled by their surface, i.e., non-uniformity in structure and charge. This heterogeneity of surface is considered responsible for promoting specific dye adsorption areas creating dye “islands” with local dye supersaturations.

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Synthesis of Zeolites from Fine-Grained Perlite and Their Application as Sorbents

Cited by 6 publications

References 66 publications

Hydration of MgO: Reaction Kinetics and pH Control on Brucite Crystal Morphology

Hydration of MgO: Reaction Kinetics and pH Control on Brucite Crystal Morphology

Substantial Copper (Cu2+) Uptake by Metakaolin-Based Geopolymer and Its Resistance to Acid Leaching and Ion Exchange

C.I. Acid Black 1 transfer from dilute solution to perlite framework in organic waste management

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