Effects of polar modifiers on supercritical extraction efficiency for organic template removal from mesoporous MCM-41 materials

Huang, Zhen; Li, Jinghuan; Li, Huishan; Teng, Li-jun; Kawi, Sibudjing; Lai, M.W.

doi:10.1016/j.supflu.2013.06.012

Cited by 10 publications

(8 citation statements)

References 30 publications

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“…Previous studies suggested that coating Fe 3 O 4 @SiO 2 with a mesoporous silica shell increases the surface area and provides better adsorption capacity [19][20][21]. To synthesis the mesoporous silica shell, organic templates must be extracted from the structure adopting different strategies such as calcination at high temperature, supercritical fluid CO2 (SCF-CO2) extraction and solvent extraction [22][23][24]. Although several scientists utilized calcination methods, it fails to guarantee the stability of the structure during the process.…”

Section: Introductionmentioning

confidence: 99%

Enhancement of Cd2+ removal from aqueous solution by multifunctional mesoporous silica: Equilibrium isotherms and kinetics study

Javaheri

Kheshti

Ghasemi

et al. 2019

Separation and Purification Technology

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In this work, a novel amino-functionalized mesoporous microsphere was synthesized to remove cadmium ions from water. The Fe 3 O 4 @SiO 2 @m-SiO 2 -NH 2 micro-spheres were successfully prepared via a facile two-stage process by coating of the as-synthesized magnetic cores with a silica shell followed by increasing the porosity of the structure using a cationic surfactant as structure-directing agents. The template removal from the structure has been performed following the method of solvent extraction and methanolenhanced supercritical fluid CO2 (SCF-CO2) extraction. This novel approach provides the multifunctional microspheres with a high surface area, which improves the adsorption capacity of adsorbent.Characterization of the as-synthesized adsorbent were analytically determined showing that as-prepared adsorbent has a significant surface area of 637.38 m 2 g -1 . The kinetic data agreed with pseudo-second-order model and Langmuir isotherm. The maximum adsorption capacity of the synthesized adsorbent was about 884.9 mg g -1 , and can be easily separated from solution under an external magnetic field. The synthesized microspheres were recycled using HCl and cadmium removal was over 92% after 6 cycles, which confirms the chemical stability and reusability of the manufactured particles.

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Section: Introductionmentioning

confidence: 99%

Enhancement of Cd2+ removal from aqueous solution by multifunctional mesoporous silica: Equilibrium isotherms and kinetics study

Javaheri

Kheshti

Ghasemi

et al. 2019

Separation and Purification Technology

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“…Andrographolide is a polar compound contained in the leaves; therefore, it will dissolve more readily and to a greater extent in a more polar solvent . In addition, the presence of ethanol in the supercritical CO 2 increased the polarity and bulk density of the supercritical solvent mixture resulted in an enhanced of its solvating power, which can also be advantageous for the dissolution of the andrographolide into the bulky SCF solvent, resulting in good extraction results . It is proven that a cosolvent can overcome the strong interactions between the secondary metabolite and cellulosic matrix, which may be in the form of hydrogen bonding between the andrographolide and the cellulosic structure of the leaves .…”

Section: Results and Discussionmentioning

confidence: 99%

Extraction of Andrographolide from Andrographis paniculata Dried Leaves Using Supercritical CO₂ and Ethanol Mixture

Kumoro

Hasan

Singh

2018

Ind. Eng. Chem. Res.

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The increase in the number of world's elderly population and changes in their lifestyle has triggered to the formation of diseases susceptible communities. Inherent with the aforementioned conditions, the need in andrographolide as one of natural remedies isolated from the leaves of Andrographis paniculata also increases. In this work, supercritical fluid extraction employing CO 2 −ethanol mixture as solvent has shown its capability in extracting andrographolide from dried leaves of A. paniculata. The andrographolide yield largely increased when the ethanol concentration in the solvent mixtures was increased from 0 to 12.5 mol %, but there was no significant increase in andrographolide yield as ethanol concentration was further increased. Although an enhancement of both temperature and pressure gave favorable effects on the yield of andrographolide, a crossover effect existed in this supercritical system causing no significant increase of andrographolide yield. The downflow mode performed the highest extraction efficiency compared to both upflow and horizontal-flow modes. Supercritical CO 2 −ethanol mixture containing 12.5 mol % ethanol flowed at 2 mL/min according to downflow mode at 323 K and 15 MPa was found to be the most effective in extracting andrographolide. The integral desorption model satisfactory described the extraction profile as shown by its low average error of about 5%.

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“…Since CO 2 as a special chemical with a low critical temperature of 304.21 K and modest critical pressure of 7.38 MPa is cost effective, available, low toxic, and nonflammable, , SC–CO 2 has attracted more attention of material scientists. SC–CO 2 in the presence or absence of cosolvents has been employed for template removal from mesoporous materials, ,,− as shown in Figure . van Grieken et al extracted the nonionic surfactant from SBA-15 using SC–CO 2 in the presence and absence of ethanol as a cosolvent at various pressures and temperatures ranging from 60 to 110 °C for 24 h. The results disclosed that optimum removal efficiency of 79% is obtained upon using SC–CO 2 at 90 °C and 140 atm, while the efficiency is decreased to 76% by increasing temperature to 110 °C at 210 atm due to the lower density of the supercritical fluid.…”

Section: Template Removal Approachesmentioning

confidence: 99%

Review on Template Removal Techniques for Synthesis of Mesoporous Silica Materials

Ghaedi

Zhao

2022

Energy Fuels

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The key step in the preparation of mesoporous silica materials is the removal of organic templates occluded inside the pores including nonionic, cationic, anionic surfactants and even ionic liquid (IL). The most common method to remove templates is conventional calcination under air at 550 °C. Although templates can be completely removed from the pores, calcination suffers many serious drawbacks including significant framework shrinkage, the collapse of the ordered structure, reduction of silanol concentrations on the pore wall (which are of high importance for postmodification), generation of large amounts of CO 2 and organic amine compounds, the presence of carbon deposits or coke as a contaminant, elimination of organic functionalities (such as organoalkoxysilanes with amino groups), and the inability to recover or reuse expensive organic templates. That is why many attempts have been reported in the literature to develop novel methods for removing organic templates that are favorable from both economic and environmental standpoints for potentially large-scale applications. The current study reviews the recent development methods for template removal from various types of mesoporous silica materials. We have divided the template removal approaches into two categories: physical method and chemical method. The effects of those methods are discussed in detail on the textural and structural properties of mesoporous silica materials along with the template removal mechanism and their pores and coins.

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Effects of polar modifiers on supercritical extraction efficiency for organic template removal from mesoporous MCM-41 materials

Cited by 10 publications

References 30 publications

Enhancement of Cd2+ removal from aqueous solution by multifunctional mesoporous silica: Equilibrium isotherms and kinetics study

Enhancement of Cd2+ removal from aqueous solution by multifunctional mesoporous silica: Equilibrium isotherms and kinetics study

Extraction of Andrographolide from Andrographis paniculata Dried Leaves Using Supercritical CO₂ and Ethanol Mixture

Review on Template Removal Techniques for Synthesis of Mesoporous Silica Materials

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Effects of polar modifiers on supercritical extraction efficiency for organic template removal from mesoporous MCM-41 materials

Cited by 10 publications

References 30 publications

Enhancement of Cd2+ removal from aqueous solution by multifunctional mesoporous silica: Equilibrium isotherms and kinetics study

Enhancement of Cd2+ removal from aqueous solution by multifunctional mesoporous silica: Equilibrium isotherms and kinetics study

Extraction of Andrographolide from Andrographis paniculata Dried Leaves Using Supercritical CO2 and Ethanol Mixture

Review on Template Removal Techniques for Synthesis of Mesoporous Silica Materials

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Extraction of Andrographolide from Andrographis paniculata Dried Leaves Using Supercritical CO₂ and Ethanol Mixture