Understanding the hydrothermal, thermal, mechanical and hydrolytic stability of mesoporous KIT-6: A comprehensive study

Kishor, Rupak; Ghoshal, Aloke Kumar

doi:10.1016/j.micromeso.2017.01.020

Cited by 32 publications

(16 citation statements)

References 56 publications

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“…In the early 1990s, Mobil Oil Corporation researchers published the first syntheses of mesoporous materials (M41S), which were manufactured using an alkyltriethylammonium halide as a template in an alkaline medium [3,4]. These new compounds presented very characteristic and peculiar properties, such as a high specific surface area (up to 1400 m 2 g −1 ), a pore volume greater than 0.5 cm 3 g −1 and narrowly distributed cylindrical pores (2-30 nm) [5]. The physicochemical properties of these compounds have been tested and evaluated by many researchers [6][7][8][9][10][11][12].…”

Section: Introductionmentioning

confidence: 99%

“…However, there are boundaries to the temperature used in all SBA-15 and KIT-6 synthesis processes. The use of a high temperature is necessary for the formation of mesoporous materials, through the condensation of hydroxyls, to form siloxane bonds, but several studies have demonstrated the effects on the quality of the temperature-related MNS formation used during a static hydrothermal synthesis of SBA-15 [53][54][55] and KIT-6 [5]. Nevertheless, during the calcination process, these bonds are consolidated, giving rise to the desired material when the largest loss of surface silanol groups occurs; however, too great a loss leaves the material unusable for functionalization.…”

Section: Introductionmentioning

confidence: 99%

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Tunable Effect of the Calcination of the Silanol Groups of KIT-6 and SBA-15 Mesoporous Materials

et al. 2020

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The calcination process is a crucial step during SBA-15 and KIT-6 synthesis. It is used to completely remove the organic template and condense silanol groups, and it allows the determination of the textural and physical properties of these materials, depending on the adopted conditions. Moreover, calcination influences the number of silanols available on the surface of the material. The concentration of silanols is important if these materials were synthesized for use in adsorption or functionalization. To understand and optimize the silanol groups of SBA-15 and KIT-6, in this study, the temperature and time calcination parameters were varied. The experiments were performed at 300, 400, and 500 °C for 300, 400, and 500 min. The results show that the ideal temperature to preserve the silanol groups is 300 °C, but to optimize the textural properties, it is better to calcine these molecular sieves at 400 °C. A calcination for 10 h did not give better results than a calcination for 5 h, demonstrating that the former duration is excessive for use.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Tunable Effect of the Calcination of the Silanol Groups of KIT-6 and SBA-15 Mesoporous Materials

et al. 2020

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“…Later, other related mesoporous silica materials, namely MCM-48, MCM-50, and SBA-15, were synthesized [121]. Recently, more robust mesoporous silica materials have been presented, such as, TUD-1 [122], FDU-12 [123], or KIT-6 [124]. However, despite MMS materials possessing large pores when compared to zeolites, which allows for improving molecular diffusion, and some improvement on the stability having been attained in the last years, their lack of acidity hinders the application of these materials to a wide range of catalytic reactions, when compared with traditional zeolites [121], limiting their use mainly as catalyst supports.…”

Section: Mesoporous Silicas and Composite Hierarchical Materialsmentioning

confidence: 99%

Zeolites and Related Materials as Catalyst Supports for Hydrocarbon Oxidation Reactions

et al. 2022

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Catalytic oxidation is a key technology for the conversion of petroleum-based feedstocks into useful chemicals (e.g., adipic acid, caprolactam, glycols, acrylates, and vinyl acetate) since this chemical transformation is always involved in synthesis processes. Millions of tons of these compounds are annually produced worldwide and find applications in all areas of chemical industries, ranging from pharmaceutical to large-scale commodities. The traditional industrial methods to produce large amounts of those compounds involve over-stoichiometric quantities of toxic inorganic reactants and homogeneous catalysts that operate at high temperature, originating large amounts of effluents, often leading to expensive downstream processes, along with nonrecovery of valuable catalysts that are loss within the reactant effluent. Due to the increasingly stringent environmental legislation nowadays, there is considerable pressure to replace these antiquate technologies, focusing on heterogeneous catalysts that can operate under mild reactions conditions, easily recovered, and reused. Parallelly, recent advances in the synthesis and characterization of metal complexes and metal clusters on support surfaces have brought new insights to catalysis and highlight ways to systematic catalysts design. This review aims to provide a comprehensive bibliographic examination over the last 10 years on the development of heterogeneous catalysts, i.e., organometallic complexes or metal clusters immobilized in distinct inorganic supports such as zeolites, hierarchical zeolites, silicas, and clays. The methodologies used to prepare and/or modify the supports are critically reviewed, as well as the methods used for the immobilization of the active species. The applications of the heterogenized catalysts are presented, and some case-studies are discussed in detail.

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“…Reusability is a critical challenge that must be addressed for the development of large-scale, cost-effective adsorptive desulfurization. The advantage of zeolites and mesoporous silicas, in comparison to MOFs, is that these materials possess a relatively high thermal stability, up to ∼650–1200 °C. ,− This property enables the adsorbents to be easily regenerated via calcination. From a cost standpoint, the ideal adsorbent would be regenerable by simple air calcination, as opposed to calcination under more expensive gas flows or with the use of a solvent, because of its practicality for on-board fuel cell applications and affordability.…”

Section: Regeneration Studymentioning

confidence: 99%

Desulfurization of Liquid Hydrocarbon Fuels with Microporous and Mesoporous Materials: Metal-Organic Frameworks, Zeolites, and Mesoporous Silicas

Crandall

Zhang

Stavila

et al. 2019

Ind. Eng. Chem. Res.

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This review discusses potential microporous and mesoporous materials that can address the issue of sulfur reduction via adsorptive desulfurization (ADS) with a focus on liquid fuels. During the transition to cleaner energy sources in the face of climate change, liquid fossil fuels will likely continue to provide a significant share of the world's energy demand. Fossil fuels possess a substantial amount of deleterious sulfur compounds that reduce the efficiency of energy production, damage the environment, and harm human health. There has recently been a large push to address these challenges that sulfur presents. ADS is one of the most promising techniques to reduce the sulfur content of liquid fuels in a cost-effective manner. The three key materials that have attracted a great deal of attention for their application in ADS are metal-organic frameworks (MOFs), zeolites, and mesoporous silicas. These materials have emerged as potential candidates for ADS because of their high surface area, tunable structure, and advantageous porosity. Research interest has been generated around finding unique approaches to modify these materials that increase their selectivity, stability, adsorption capacity, and reusability. A deeper mechanistic understanding of the adsorption of various sulfur compounds on these novel materials has been pursued experimentally and with the aid of models. This review seeks to discuss the recent advances made surrounding the most promising ADS materials while providing an outlook on where advancements still need to be made.

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Understanding the hydrothermal, thermal, mechanical and hydrolytic stability of mesoporous KIT-6: A comprehensive study

Cited by 32 publications

References 56 publications

Tunable Effect of the Calcination of the Silanol Groups of KIT-6 and SBA-15 Mesoporous Materials

Tunable Effect of the Calcination of the Silanol Groups of KIT-6 and SBA-15 Mesoporous Materials

Zeolites and Related Materials as Catalyst Supports for Hydrocarbon Oxidation Reactions

Desulfurization of Liquid Hydrocarbon Fuels with Microporous and Mesoporous Materials: Metal-Organic Frameworks, Zeolites, and Mesoporous Silicas

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