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Chencheni A, Belkhiri S, Tarchoun AF, Abdelaziz A, Bessa W, Boucheffa Y, Trache D. Unravelling the thermal behavior and kinetics of unsaturated polyester resin supplemented with organo-nanoclay. RSC Adv 2024; 14:517-528. [PMID: 38173583 PMCID: PMC10759040 DOI: 10.1039/d3ra06076d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Accepted: 12/11/2023] [Indexed: 01/05/2024] Open
Abstract
The integration of nanoclays within polymeric systems to develop high-performance materials is an emerging research field that has garnered significant attention. In this context, an organically modified montmorillonite (OMMT) is utilized as a reinforcing agent for unsaturated polyester resin (UPR) with loads of 1%, 3%, and 5 wt%. The modification of montmorillonite nanoclay (MMT) using a quaternary ammonium compound is performed through an effective repetitive modification process under reflux conditions. The curing behavior of the unsaturated polyester resin containing organically modified clay catalyzed with methyl ethyl ketone peroxide (MEKP) initiator and promoted by cobalt naphthenate accelerator is investigated using dynamic differential scanning calorimetry (DSC) followed by kinetic analysis using isoconversional methods. The dynamic DSC curing curves showed a bimodal exothermic peak, where two independent reactions, namely, redox and thermal decomposition of the initiator occurred. In this study, novel insights into the curing reaction of the studied UPR and UPR/OMMT systems have been revealed through the application of the Trache-Abdelaziz-Siwani (TAS) and Sbirrazzuoli (VYA/CE) isoconversional methods. These methods have enabled the elucidation of the intricate mechanisms and phenomena that impact the curing reaction, including the dilution effect in the redox reaction and the diffusion phenomenon at the end of the thermal decomposition reaction. The incorporation of nanoclay into unsaturated polyester resin (UPR) resulted in a reduction in the activation energy for both the redox and thermal reactions. Specifically, the energetic barrier decreased from 93.85 and 101.58 kJ mol-1 for pristine UPR to 60.71 and 72.93 kJ mol-1 for UPR/OMMT-5 in the redox and thermal reactions, respectively. The addition of OMMT caused a significant decrease in the pre-exponential factor. The values of UPR/OMMT-5 were 2.75 × 105 and 5.50 × 106 for the redox and thermal decomposition reactions, respectively, compared to 1.41 × 1012 and 5.13 × 1013 for UPR. The thermogravimetric analysis demonstrated that UPR/OMMT systems were more stable than UPR.
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Affiliation(s)
- Ayoub Chencheni
- Energetic Propulsion Laboratory, Teaching and Research Unit of Energetic Processes, Ecole Militaire Polytechnique BP 17, Bordj El-Bahri Algiers 16046 Algeria
| | - Samir Belkhiri
- Energetic Propulsion Laboratory, Teaching and Research Unit of Energetic Processes, Ecole Militaire Polytechnique BP 17, Bordj El-Bahri Algiers 16046 Algeria
| | - Ahmed Fouzi Tarchoun
- Energetic Propulsion Laboratory, Teaching and Research Unit of Energetic Processes, Ecole Militaire Polytechnique BP 17, Bordj El-Bahri Algiers 16046 Algeria
| | - Amir Abdelaziz
- Energetic Materials Laboratory, Teaching and Research Unit of Energetic Processes, Ecole Militaire Polytechnique BP 17, Bordj El-Bahri Algiers 16046 Algeria
| | - Wissam Bessa
- Energetic Materials Laboratory, Teaching and Research Unit of Energetic Processes, Ecole Militaire Polytechnique BP 17, Bordj El-Bahri Algiers 16046 Algeria
| | - Youcef Boucheffa
- Faculty of Chemistry, University of Sciences and Technology Houari Boumediene Bab El-Zouar Algiers Algeria
| | - Djalal Trache
- Energetic Materials Laboratory, Teaching and Research Unit of Energetic Processes, Ecole Militaire Polytechnique BP 17, Bordj El-Bahri Algiers 16046 Algeria
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Mechanisms for cation exchange at the interfaces of montmorillonite nanoparticles: Insights for Pb2+ control. Colloids Surf A Physicochem Eng Asp 2022. [DOI: 10.1016/j.colsurfa.2022.128556] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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You X, Wu L, Wang D, Xue Z, Zhao M, Wang X, Liu Q, Tang N. Preparation of C 3N 4/montmorillonite composite photocatalyst for effective removal of organic pollutants. ENVIRONMENTAL TECHNOLOGY 2022; 43:1513-1521. [PMID: 33086988 DOI: 10.1080/09593330.2020.1841303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2020] [Accepted: 10/16/2020] [Indexed: 06/11/2023]
Abstract
Due to the good photocatalytic performance, which ensures the decomposition of pollutants under light, g-C3N4 is considered as an ideal photocatalytic material. Montmorillonite has a high adsorption capacity and layered structure, which has positive effects on increasing the specific surface area of g-C3N4 and avoid its polymerization agglomeration. In this paper, montmorillonite was used as carrier for g-C3N4 to obtain a new photocatalytic composite g-C3N4/Mt. Then the morphological and (micro)structural properties were characterized. The well-characterized materials were evaluated for the photocatalytic activity in degradation of methylene blue and Bisphenol A. The effects of the mass fraction of g-C3N4, light irradiation time, and pollutant concentration on the photocatalytic performance of g-C3N4/Mt composites were studied. Under the optimal experimental plan, the rate of photocatalytic degradation can reach to 99.3% within 120 min. Through the MS spectrum, it can be found that methylene blue molecule were catalysed and degraded into many harmless substances with low-molecular weight. Finally, based on the obtained reaction products, the mechanism by which the pollutants are removed was proposed. This study provides a new strategy to improve the photocatalysis ability of g-C3N4, which is of great significance for a sustainable pollution treatment.
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Affiliation(s)
- Xujia You
- School of Materials Science and Engineering, Shenyang Jianzhu University, Shenyang, People's Republic of China
| | - Limei Wu
- School of Materials Science and Engineering, Shenyang Jianzhu University, Shenyang, People's Republic of China
| | - Deqiang Wang
- School of Materials Science and Engineering, Shenyang Jianzhu University, Shenyang, People's Republic of China
| | - Zhichao Xue
- School of Science, Shenyang Jianzhu University, Shenyang, People's Republic of China
| | - Mingyu Zhao
- School of Materials Science and Engineering, Shenyang Jianzhu University, Shenyang, People's Republic of China
| | - Xiaolong Wang
- Procurement and Bidding Office, Shenyang Jianzhu University, Shenyang, People's Republic of China
| | - Qingxin Liu
- School of Materials Science and Engineering, Shenyang Jianzhu University, Shenyang, People's Republic of China
| | - Ning Tang
- School of Materials Science and Engineering, Shenyang Jianzhu University, Shenyang, People's Republic of China
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Liu L, Zhang C, Jiang W, Li X, Dai Y, Jia H. Understanding the sorption behaviors of heavy metal ions in the interlayer and nanopore of montmorillonite: A molecular dynamics study. JOURNAL OF HAZARDOUS MATERIALS 2021; 416:125976. [PMID: 34492884 DOI: 10.1016/j.jhazmat.2021.125976] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Revised: 04/21/2021] [Accepted: 04/23/2021] [Indexed: 06/13/2023]
Abstract
The molecular-scale adsorption mechanism of heavy metal ions in the interlayer and nanopore regions of montmorillonite (MMT) were investigated by molecular dynamics simulations. Three typical heavy metals (zinc, cadmium, and lead) were selected as the model ions, and two types of MMT (Arizona and Wyoming) were considered. The results showed that Cd2+ and Pb2+ can form both inner- and outer-sphere complexes on Wyoming MMT, while Zn2+ only formed outer-sphere complex due to the stronger hydration interaction of Zn2+ than Cd2+ and Pb2+. For Arizona MMT, all of the three ions only formed outer-sphere complexes on its interlayer and external basal surface in which the cations remained a fully hydrated state. The calculated diffusion coefficients of three cations in interlayer and nanopore indicated that their diffusion abilities were significantly impaired, implying that MMT adsorbents have a strong ability to fix and retard heavy metal ions. The derived results and mechanisms are instrumental to a profound understanding of the transport and retention of heavy metal elements in subsurface environments, and provide guidance for the management of heavy metal pollution.
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Affiliation(s)
- Libin Liu
- Key Laboratory of Plant Nutrition and the Agri-environment in Northwest China, College of Natural Resources and Environment, Northwest A & F University, Yangling 712100, China
| | - Chi Zhang
- Key Laboratory of Plant Nutrition and the Agri-environment in Northwest China, College of Natural Resources and Environment, Northwest A & F University, Yangling 712100, China; State Key Laboratory of Soil Erosion and Dryland Farming on Loess Plateau, Northwest A&F University, Yangling 712100, China.
| | - Wenjun Jiang
- Key Laboratory of Plant Nutrition and the Agri-environment in Northwest China, College of Natural Resources and Environment, Northwest A & F University, Yangling 712100, China
| | - Xiong Li
- Key Laboratory of Plant Nutrition and the Agri-environment in Northwest China, College of Natural Resources and Environment, Northwest A & F University, Yangling 712100, China; State Key Laboratory of Soil Erosion and Dryland Farming on Loess Plateau, Northwest A&F University, Yangling 712100, China
| | - Yunchao Dai
- Key Laboratory of Plant Nutrition and the Agri-environment in Northwest China, College of Natural Resources and Environment, Northwest A & F University, Yangling 712100, China; State Key Laboratory of Soil Erosion and Dryland Farming on Loess Plateau, Northwest A&F University, Yangling 712100, China
| | - Hanzhong Jia
- Key Laboratory of Plant Nutrition and the Agri-environment in Northwest China, College of Natural Resources and Environment, Northwest A & F University, Yangling 712100, China; State Key Laboratory of Soil Erosion and Dryland Farming on Loess Plateau, Northwest A&F University, Yangling 712100, China.
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Zhu C, Huang X, Li T, Wang Q, Yang G. Mechanisms for Cr(VI) reduction by alcohols over clay edges: Reactive differences between ethanol and ethanediol, and selective conversions to Cr(IV), Cr(III) and Cr(II) species. J Colloid Interface Sci 2021; 603:37-47. [PMID: 34186408 DOI: 10.1016/j.jcis.2021.06.123] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 06/19/2021] [Accepted: 06/21/2021] [Indexed: 11/30/2022]
Abstract
Catalytic reduction by alcohols over clay minerals works efficiently under a wide range of pH and represents an emerging approach to control Cr(VI) contamination. Herein, mechanisms for Cr(VI) adsorption and reduction at clay edges are addressed by dispersion-corrected periodic DFT calculations, considering different active sites, and types (monohydric and polyhydric) and coverage of alcohols. Cr(VI) adsorbs favorably at clay edges, forming direct bonds and strong H-bonds. Mechanisms for Cr(VI) reduction by alcohols are largely determined by π-conjugation development, and efficient conversion conduces to Cr(VI) removal. Cr(II), Cr(III) and Cr(IV) are useful for different purposes, and high selectivity towards these products is realized through rational catalysts design: 1) Cr(IV) dominates at Al3+ site with all ethanol coverage, Al3+ site with high-coverage ethanediol, and Mg2+ site with low-coverage ethanol; 2) Cr(III) dominates at Al3+ and Mg2+ sites with low-coverage ethanediol; 3) Cr(II) dominates at Mg2+ site with high-coverage ethanol or ethanediol. Results agree finely with experimental observations available, and significant new insights have been provided for Cr management and recycling. Detailed electronic structure and vibrational analyses, which can also guide future experimental studies, manifest that Cr(VI) reduction progresses are effectively monitored by ESR and FT-IR techniques.
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Affiliation(s)
- Chang Zhu
- College of Resources and Environments & Chongqing Key Laboratory of Soil Multi-scale Interfacial Process, Southwest University, Chongqing 400715, China
| | - Xiaoxiao Huang
- College of Resources and Environments & Chongqing Key Laboratory of Soil Multi-scale Interfacial Process, Southwest University, Chongqing 400715, China
| | - Tingting Li
- College of Resources and Environments & Chongqing Key Laboratory of Soil Multi-scale Interfacial Process, Southwest University, Chongqing 400715, China
| | - Qian Wang
- College of Resources and Environments & Chongqing Key Laboratory of Soil Multi-scale Interfacial Process, Southwest University, Chongqing 400715, China
| | - Gang Yang
- College of Resources and Environments & Chongqing Key Laboratory of Soil Multi-scale Interfacial Process, Southwest University, Chongqing 400715, China.
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Qian F, Guo M, Qian Z, Zhao B, Li J, Wu Z, Liu Z. Enabling highly structure stability and adsorption performances of Li1.6Mn1.6O4 by Al-gradient surface doping. Sep Purif Technol 2021. [DOI: 10.1016/j.seppur.2021.118433] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Yang G, Zhou L. Montmorillonite-catalyzed conversions of carbon dioxide to formic acid: Active site, competitive mechanisms, influence factors and origin of high catalytic efficiency. J Colloid Interface Sci 2020; 563:8-16. [PMID: 31865051 DOI: 10.1016/j.jcis.2019.12.064] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2019] [Revised: 12/10/2019] [Accepted: 12/15/2019] [Indexed: 11/30/2022]
Abstract
Design of heterogeneous catalysts for CO2 conversions to value-added chemicals is highly desirable. Montmorillonite and other clay minerals have been used widely in catalytic reactions including CO2 hydrogenation, while a molecular-level understanding remains lacking. In this study, periodic density functional theory calculations are employed and a comprehensive understanding about montmorillonite-catalyzed CO2 hydrogenation to formic acid is given, including active site, mechanism, influence factors, competitive reaction paths, and origin of superior catalysis. Catechol that is readily available and can also be considered as a fragment of abundantly distributed humic substances is an effective hydrogen source. The penta-coordinated M3+ (M2+) sites of edge surfaces are active sites, and reactions occur preferentially at M2+ rather than M3+ sites. The catalytic activities depend strongly on the identity of M2+ (M3+) cations, and all reaction paths follow the concerted mechanisms transferring two hydrogen atoms in one step, with those producing formate being highly preferred. M2+/Al3+ substitutions and substituent effects are two critical factors to affect catalytic activities, and with synergy of Mg2+/Al3+ substitutions and -NMe2 substituent, reactions are exergonic (-0.09 eV) and activation barriers are so low (0.48 eV) that formate can be facilely produced at ambient conditions. Edge surfaces of clay minerals are bifunctional catalysts, with M2+ cations showing Lewis acids and MOH groups playing similar effects as basic additives. Results provide new insights about heterogeneous catalysis of CO2 hydrogenation and other reactions.
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Affiliation(s)
- Gang Yang
- College of Resources and Environment & Chongqing Key Laboratory of Soil Multi-scale Interfacial Process, Southwest University, Chongqing 400715, China; State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China.
| | - Lijun Zhou
- College of Resources and Environment & Chongqing Key Laboratory of Soil Multi-scale Interfacial Process, Southwest University, Chongqing 400715, China
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