Exploratory Synthesis of Low-Silica Nanozeolites through Geopolymer Chemistry

Chen, Shaojiang; Zhang, Wenwen; Sorge, Lukas P.; Seo, Dong Kyun

doi:10.1021/acs.cgd.8b01636

Cited by 13 publications

(10 citation statements)

References 27 publications

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“…The synthetic zeolite used in this study, synthesized by our team through a “geopolymer gel” route, is a sodium aluminosilicate product containing Faujasite, Linda type A, and Sodalite frameworks for the precursor mixture compositions of Si/Al = 2 and Na/Al = 3 . The pure phase of Faujasite is obtained only in ratios of Si/Al = 3 and Na/Al = 4, which implies a narrow phase region for the structure . However, considering the large size of the pore openings in Faujasite nanozeolites and their high capacity as a carrier, we modeled a Faujasite-type zeolite for our DFT calculations.…”

Section: Methodsmentioning

confidence: 99%

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Reducing the Carbon Footprint of Bituminous Composites Using Amine-Impregnated Zeolite

Mousavi

Aldagari

Seo

et al. 2022

ACS Sustainable Chem. Eng.

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Moisture damage in bituminous composites is a major concern, reducing the service life of infrastructures. The use of lime and amine-based additives to mitigate the damage has been practiced in the industry. Lime production is an inherently carbon-intensive process involving large quantities of CO2 emissions. Amine-based additives lose their effectiveness over time when exposed to weathering and UV irradiation. Inspired by the technology of amine-functionalized porous materials, here, we study the merits of using amine-impregnated zeolite in bituminous composites to protect amines from weathering and UV. We hypothesize that some of the ethylenediamine molecules loaded into the zeolite’s pores are gradually released into the matrix of bitumen, with the protection in the zeolite’s pores allowing the ethylenediamine molecules to maintain their effectiveness as antistripping agents until their release. Our laboratory experiments used the moisture-induced shear-thinning index to compare the moisture resistance of samples with amine-impregnated zeolite to samples with amines and zeolite added separately. Initially (before aging), the samples with amines and zeolite added separately have higher resistance to moisture damage compared to amine-impregnated zeolite (in which 52% of the total amines are retained in the zeolite). The superior performance of amine-impregnated zeolite is shown after short-term laboratory aging. After short-term aging and throughout long-term aging in the laboratory, the comparative resistance to moisture damage increasingly favored the amine-impregnated zeolite owing to the slow release of retained amines under an external stimulus induced by aging. This slow release of retained amines extends the effectiveness of the amines as the amines retained within zeolite pores are protected from early aging. Our quantum-based calculations using density functional theory (DFT) show that some small polar compounds of bitumen take advantage of stronger interactions with zeolite’s active sites to substitute for amine molecules; this could be a driving force for the gradual release of amine molecules from zeolite to the bitumen matrix. Our DFT studies on seven polar compounds of bitumen (quinoline, pyridine, benzofuran, benzoic acid, hexanal, 3-pentylthiophene, and hexanethiol) show that many of these compounds have stronger interactions with the zeolite model, particularly in the exterior walls of the intact sodalite cage ({111} face) and supercage-window sites, leading to deliver the loaded substance (ethylenediamine) into the medium. In contrast, amine molecules grafted onto the active sites of the broken sodalite cage ({100} cut) benefit from many H-bonding interactions at this active site, so these amine molecules are not easily substituted or released into the bitumen matrix.

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Section: Methodsmentioning

confidence: 99%

“…The research plan performed in this study is shown in Scheme . The zeolite model used in the DFT-D calculations is a Faujasite-type zeolite identified and characterized in a typical synthetic zeolite used in our study …”

Section: Introductionmentioning

confidence: 99%

Reducing the Carbon Footprint of Bituminous Composites Using Amine-Impregnated Zeolite

Mousavi

Aldagari

Seo

et al. 2022

ACS Sustainable Chem. Eng.

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“…17,18 In this study, nanozeolites are believed to be a promising carrier for large paraffin molecules due to nanozeolites' large external surface areas and large pore volumes. The scalable synthesis recently developed 19 makes nanozeolites more promising for further practical uses.…”

Section: ■ Introductionmentioning

confidence: 99%

“…Because of these unique features, nanozeolites have demonstrated an improved efficiency in their conventional catalysis, separation, and other emerging applications in areas such as medicine, antimicrobials, and the food industry. , In this study, nanozeolites are believed to be a promising carrier for large paraffin molecules due to nanozeolites’ large external surface areas and large pore volumes. The scalable synthesis recently developed makes nanozeolites more promising for further practical uses.…”

Section: Introductionmentioning

confidence: 99%

Effects of Wax-Impregnated Nanozeolites on Bitumen’s Thermomechanical Properties

Samieadel

Chen

Ciota

et al. 2020

ACS Sustainable Chem. Eng.

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This study presents a new carrier for wax-based additives used in bitumen; the new carrier alleviates wax crystallization while improving bitumen’s cohesion, adhesion, and elastic properties. The abovementioned wax carrier is a newly developed nanozeolite, which is impregnated with paraffin wax to form a hybrid additive referred to as Winz. Bitumen containing Winz showed an improved resistance to low-temperature cracking, which can be attributed to reduced wax crystallization when wax dispersed via nanozeolite. In addition, nanozeolite was found to adsorb acidic compounds of bitumen upon its release of wax. Our molecular modeling showed that while wax interacts with nanozeolite in the absence of acid, upon introduction of acid, wax molecules are replaced by acid molecules on the nanozeolite surface. Adsorption of acids to the nanozeolite surface was also evidenced in the significant change of shear-thinning behavior of bitumen doped with Winz when bitumen was exposed to water. Hydrolysis of acidic compounds at the surface of nanozeolite caused a 42% reduction in the shear-thinning rate (going from 3.25 to 1.89) after water conditioning. This in turn shows that bitumen acids were adsorbed to Winz and detracted from the interface of bitumen with stones. Therefore, Winz can be a promising candidate to promote sustainability by enhancing the durability of bituminous composites via reducing bitumen’s wax crystallization and bitumen’s acid accumulation at the stone interface. The study outcomes provide insights to synthesize multifunctional carriers for bitumen’s wax-based additives to enhance their dispersion and effectiveness.

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“…Liguori et al [15] obtained a self-supporting zeolitic material with a hierarchical porosity by combining zeolite crystallization with a foaming process initiated by silicon and found that the silicon content, the relative humidity and curing time had great effect on the nucleation and growth of zeolite phases. Chen et al [16] had successfully synthesized various low-silica nanozeolites including FAU, cancrinite (CAN), Linde-Type A (LTA), and sodalite (SOD) by exploring geopolymeric Na-Al-Si-H 2 O quaternary phase diagram. Compared to NaA(4.1 Å) and Na-P1(3.5 Å) [17,18], faujasite (FAU) has a characteristic pore size of 7.4 Å and a unique supercage structure, which is widely used in the field of heavy metal ion adsorption [19,20].…”

Section: Introductionmentioning

confidence: 99%

Evolution of Zeolite Crystals in Self-Supporting Faujasite Blocks: Effects of Hydrothermal Conditions

Guan

Wang

2019

Materials

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In order to prepare self-supporting faujasite (FAU) zeolite, a self-supporting zeolite block was synthesized in situ by hydrothermal treatment of a metakaolin base geopolymer. The effects of hydrothermal conditions such as hydrothermal alkalinity, temperature and time on the phase composition, microstructure and mechanical strength of the hydrothermal samples were investigated and evidenced by a series of characterization methods such as X-ray diffraction (XRD), scanning electron microscopy (SEM), and Brunauer-Emmet-Teller (BET). The results showed that a self-supporting faujasite block could be obtained by hydrothermal treatment of the geopolymer block in 2 M NaOH solution at 90 °C for 24 h, which had high crystallinity, regular morphology and high compressive strength. The self-supporting zeolite block had a compressive strength of 11.7 MPa, a pore volume of 0.24 cm3/g, and an average pore diameter of 7.86 nm. The specific surface area and the microporous specific surface area of the self-supporting faujasite blocks were 80.36 m2/g and 19.7 m2/g, respectively.

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Exploratory Synthesis of Low-Silica Nanozeolites through Geopolymer Chemistry

Cited by 13 publications

References 27 publications

Reducing the Carbon Footprint of Bituminous Composites Using Amine-Impregnated Zeolite

Reducing the Carbon Footprint of Bituminous Composites Using Amine-Impregnated Zeolite

Effects of Wax-Impregnated Nanozeolites on Bitumen’s Thermomechanical Properties

Evolution of Zeolite Crystals in Self-Supporting Faujasite Blocks: Effects of Hydrothermal Conditions

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