Synthesis Optimization of Mesoporous MCM-41 Materials in Acidic Media

1996 ◽  
Vol 454 ◽  
Author(s):  
A. Karlsson ◽  
R. Schmidt ◽  
M. Stocker
Keyword(s):  
Low Cost ◽  
High Surface ◽  
Point Of View ◽  
High Yield ◽  
Acid Mixture ◽  
Synthesis Time ◽  
Surface Areas ◽  
Short Synthesis ◽  
Enhanced Adsorption ◽  
Mcm 41

ABSTRACTThe synthesis of MCM-41 in a highly acidic medium has been optimised. It was found that the relatively low-cost synthesis gave a material with extremely high surface areas (more than 1500 m2/g) compared to that obtained in conventional alkaline synthesis (ca 1100 m2/g). Judged by the short synthesis time, high yield, enhanced adsorption capacity, large particle size and thermal stability, the acid route to MCM-41 appears promising from an industrial point of view. Additional cost-reducing steps, such as the recycling of the “acid matrix” and the reduction of the volume of the water/acid mixture were successfully applied.

scholarly journals Development of Amperometric Laccase Biosensor through Immobilizing Enzyme in Magnesium-Containing Mesoporous Silica Sieve (Mg-MCM-41)/Polyvinyl Alcohol Matrix

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Z. Dai ◽  
M. Q. Guo ◽  
X. J. Wang ◽  
H. F. Wang ◽  
W. Y. Chen
Keyword(s):  
Mesoporous Silica ◽  
High Surface ◽  
Acetate Buffer Solution ◽  
Buffer Solution ◽  
Experimental Conditions ◽  
Surface Areas ◽  
Long Time ◽  
Good Biocompatibility ◽  
Laccase Immobilization ◽  
Mcm 41

Magnesium-containing mesoporous silica sieve (Mg-MCM-41) provided a suitable immobilization of biomolecule matrix due to its uniform pore structure, high surface areas, fast electron-transfer rate, and good biocompatibility. Based on this, an amperometric biosensor was developed by entrapping laccase into the Mg-MCM-41/PVA composite matrix. Laccase from Trametes versicolor was assembled on a composite film of Mg-MCM-41/PVA modified Au electrode and the electrode was investigated by cyclic voltammetry, impedance spectroscopy, and chronoamperometry. The results indicated that the Mg-MCM-41/PVA/Lac modified electrode exhibited excellent catalytic activity towards catechol at room temperature in pH 4.8 acetate buffer solution. The optimum experimental conditions of biosensor for the detection of catechol were studied in detail. Under the optimal conditions, the linear range was from 0.94 to 10.23 μM with the sensitivity of 16.9227 A/M, the detection limit of 0.00531 μM, and the response time of less than 14 s. The Michaelis-Menten constant (KMapp) was estimated by Lineweaver-Burk equation and theKMappvalue was about 1.01 μM. In addition, the biosensor exhibited high reproducibility and long-time stability. This work demonstrated that Mg-MCM-41/PVA composite provides a suitable support for laccase immobilization and construction of biosensor.

scholarly journals Metal Nanoparticles Supported on Al-MCM-41 via In Situ Aqueous Synthesis

2010 ◽  
Vol 2010 ◽  
pp. 1-8 ◽  
Author(s):  
Ivonne Alonso-Lemus ◽  
Ysmael Verde-Gomez ◽  
Alfredo Aguilar-Elguézabal ◽  
Lorena Álvarez-Contreras
Keyword(s):  
Metallic Nanoparticles ◽  
High Surface ◽  
Textural Properties ◽  
Active Phase ◽  
Ruthenium Catalysts ◽  
Aqueous Synthesis ◽  
Surface Areas ◽  
Electrochemical Testing ◽  
Size And Morphology ◽  
Mcm 41

MCM-41 have been used to custom synthesize catalysts in because of the controllable properties, such as pore size, active phase incorporation, crystal size, and morphology, among others. In this paper, a simple and versatile method for the incorporation of platinum, ruthenium, and palladium onto Al-MCM-41 mesoporous silica by direct inclusion of various precursors was studied. M/Al-MCM-41 structure, textural properties, morphology, and elemental composition were analyzed. The results obtained indicate that the Al-MCM-41 mesoporous-ordered structure was not affected by metallic particle incorporation. High-surface areas were obtained (1131 m2/g). Metallic nanoparticles dispersion on Al-MCM-41 was homogeneous for all samples and its particles sizes were between 6 nm to 20 nm. Microscopy results show round shape particles in platinum and palladium samples; however, ruthenium catalysts exhibit a spherical and rod shapes. Electrochemical testing for Pt/Al-MCM-41 showed electrocatalytic activity forH2oxidation which indicates that these materials can be used as a catalyst in electrochemical devices.

scholarly journals Modification of Microelectrode Arrays with High Surface Area Dendritic Platinum 3D Structures: Enhanced Sensitivity for Oxygen Detection in Ionic Liquids

Nanomaterials ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 735 ◽  
Author(s):  
Ghulam Hussain ◽  
Anthony O’Mullane ◽  
Debbie Silvester
Keyword(s):  
Surface Area ◽  
Low Cost ◽  
High Surface ◽  
High Surface Area ◽  
3D Structures ◽  
Surface Areas ◽  
Enhanced Sensitivity ◽  
Redox Active ◽  
Low Concentrations ◽  
One Step

Electrochemical gas sensors are often used for identifying and quantifying redox-active analyte gases in the atmosphere. However, for amperometric sensors, the current signal is usually dependent on the electroactive surface area, which can become small when using microelectrodes and miniaturized devices. Microarray thin-film electrodes (MATFEs) are commercially available, low-cost devices that give enhanced current densities compared to mm-sized electrodes, but still give low current responses (e.g., less than one nanoamp), when detecting low concentrations of gases. To overcome this, we have modified the surface of the MATFEs by depositing platinum into the recessed holes to create arrays of 3D structures with high surface areas. Dendritic structures have been formed using an additive, lead acetate (Pb(OAc)2) into the plating solution. One-step and two-step depositions were explored, with a total deposition time of 300 s or 420 s. The modified MATFEs were then studied for their behavior towards oxygen reduction in the room temperature ionic liquid (RTIL) [N8,2,2,2][NTf2]. Significantly enhanced currents for oxygen were observed, ranging from 9 to 16 times the current of the unmodified MATFE. The highest sensitivity was obtained using a two-step deposition with a total time of 420 s, and both steps containing Pb(OAc)2. This work shows that commercially-available microelectrodes can be favorably modified to give significantly enhanced analytical performances.

Carbon Dioxide Adsorption Using High Surface Area Activated Carbons from Local Coals Modified by KOH, NaOH and ZnCl2 Agents

2017 ◽  
Vol 15 (3) ◽  
Author(s):  
Atakan Toprak ◽  
Turkan Kopac
Keyword(s):  
Surface Area ◽  
Activated Carbons ◽  
Low Cost ◽  
High Surface ◽  
High Surface Area ◽  
Micropore Volume ◽  
Bet Surface Area ◽  
Dft Methods ◽  
Surface Areas ◽  
Adsorption Capacities

Abstract Activated carbons of various features were produced by the impregnation of local coal samples that were taken from Kilimli region of Zonguldak (Turkey) with chemical agents KOH, NaOH and ZnCl2 at different temperatures (600–800 °C) and concentrations (1:1–6:1 agent:coal), for their evaluation in CO2 adsorption studies. BET, DR, t-plot and DFT methods were used for the characterization of carbon samples based on N2 adsorption data obtained at 77 K. The pore sizes of activated carbons produced were generally observed to be in between 13–25 Å, containing highly micropores. Mesopore formations were higher in samples treated with ZnCl2. The highest value for the BET surface area was found as 2,599 m2 g−1 for the samples treated with KOH at 800 °C with a KOH to coal ratio of 4:1. It was observed that the CO2 adsorption capacities obtained at atmospheric pressure and 273 K were considerably affected by the micropore volume and surface area. The highest CO2 adsorption capacities were found as 9.09 mmol/g (28.57 % wt) and 8.25 mmol g−1 (26.65 % wt) for the samples obtained with KOH and NaOH treatments, respectively, at ratio of 4:1. The activated carbons produced were ordered as KOH>NaOH>ZnCl2, according to their surface areas, micropore volumes and CO2 adsorption capacities. The low-cost experimental methods developed by the utilization of local coals in this study enabled an effective capture of CO2 before its emission to atmosphere.

Preparation of N-Doped Nanoporous Carbon from Crude Biomass and its Electrochemical Activity

NANO ◽  
2016 ◽  
Vol 11 (03) ◽  
pp. 1650028 ◽  
Author(s):  
Zezhong Xu ◽  
Jingyu Si
Keyword(s):  
Surface Area ◽  
Low Cost ◽  
High Surface ◽  
High Surface Area ◽  
Lithium Ion ◽  
Nanoporous Carbon ◽  
High Specific Surface Area ◽  
Electrochemical Sensing ◽  
Potential Candidate ◽  
Surface Areas

H2O2 detection plays an important role in electrochemical sensing since H2O2 often acts as an intermediate product or regulator in various reactions. Nanoporous carbon (NPC) can be a potential candidate in electrochemical sensing because of its high specific surface area, various pore sizes and structures. In this work, we reported the preparation of N-doped NPC derived from the highly available, accessible and recyclable plant Typha orientalis. The products have high surface area (highest surface areas of 1439.0 m2 g[Formula: see text] and a number of nanopores. Highest content of nitrogen atom in the product is 3.66 at.%). Typical product exhibits high electrocatalytic activity for reduction of hydrogen peroxide. The product may have further use for glucose biosensing. We developed a low-cost, simple and readily scalable approach to prepare the excellent carbon electrocatalyst directly from crude biomass. In addition, because of high surface area and doping of nitrogen element, the product may find broad applications in the fields of supercapacitors, lithium-ion batteries, gas uptake and so on.

scholarly journals Enhanced adsorption capacity of porous titanium dioxide nanoparticles synthetized in alkaline sol

2020 ◽  
Vol 126 (12) ◽  
Author(s):  
Luigi Scrimieri ◽  
Luciano Velardi ◽  
Antonio Serra ◽  
Daniela Manno ◽  
Francesca Ferrari ◽  
...  
Keyword(s):  
Titanium Dioxide ◽  
Adsorption Capacity ◽  
Industrial Development ◽  
Titanium Dioxide Nanoparticles ◽  
Low Cost ◽  
High Surface ◽  
High Surface Area ◽  
Porous Titanium ◽  
Electron Microscopies ◽  
Enhanced Adsorption

Abstract In recent years, the exploitation of natural resources and industrial development have led to the production of harmful pollutants. Much of these contaminants end up in water resources, reducing the availability of drinking water. Therefore, it is necessary to find remedies to this situation. Solutions could be the adsorption or the degradation through photocatalysis of these compounds. A good candidate for this task is titanium dioxide (TiO2), due to its non-toxicity, stability and low cost. In this work, we propose a novel synthesis of TiO2 nanoparticles (NPs), with high adsorption capacity, produced at low temperature in alkaline environment. Adsorption tests were conducted using methylene blue and diclofenac as model pollutants. Moreover, the obtained NPs have been characterized through Raman spectroscopy, Scanning and Transmission electron microscopies and with thermogravimetric analysis. The results showed a porous structure with a high surface area, able to efficiently adsorb large amounts of dye from the aqueous solution. These properties make the obtained TiO2 powders suitable for applications devoted to the adsorption and recovery of harmful compounds. Graphic abstract

scholarly journals Lignin Based Activated Carbon Using H3PO4 Activation

Polymers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 2829
Author(s):  
Zhongzhi Yang ◽  
Roland Gleisner ◽  
Doreen H. Mann ◽  
Junming Xu ◽  
Jianchun Jiang ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Surface Area ◽  
Low Cost ◽  
High Surface ◽  
High Surface Area ◽  
Dye Adsorption ◽  
Nitrogen Adsorption ◽  
Bet Surface Area ◽  
Surface Areas ◽  
Adsorption Desorption

Activated carbon (AC) with a very high surface area of over 2000 m2/g was produced from low sulfur acid hydrotropic lignin (AHL) from poplar wood using H3PO4 at a moderate temperature of 450 °C (AHL-AC6). ACs with similar surface areas were also obtained under the same activation condition from commercial hardwood alkali lignin and lignosulfonate. Initial evaluation of AC performance was carried out using nitrogen adsorption-desorption and dye adsorption. AHL-AC6 exhibited the best specific surface area and dye adsorption performance. Furthermore, the adsorption results of congo red (CR) and methylene blue (MB) showed AHL-AC6 had greater adsorption capacity than those reported in literature. The dye adsorption data fit to the Langmuir model well. The fitting parameter suggests the adsorption is nearly strong and near irreversible, especially for MB. The present study for the first time provided a procedure for producing AC from lignin with Brunauer–Emmett–Teller (BET) surface area >2000 m2/g using low cost and low environmental impact H3PO4 at moderate temperatures.

scholarly journals Recent advances in the synthesis of hierarchically mesoporous TiO2 materials for energy and environmental applications

2020 ◽  
Vol 7 (11) ◽  
pp. 1702-1725 ◽  
Author(s):  
Wei Zhang ◽  
Yong Tian ◽  
Haili He ◽  
Li Xu ◽  
Wei Li ◽  
...  
Keyword(s):  
Low Cost ◽  
High Surface ◽  
Catalyst Support ◽  
Lithium Ion ◽  
Mesoporous Tio2 ◽  
Key Factors ◽  
Future Directions ◽  
Surface Areas ◽  
Tio2 Nanomaterials ◽  
Multi Level

Abstract Because of their low cost, natural abundance, environmental benignity, plentiful polymorphs, good chemical stability and excellent optical properties, TiO2 materials are of great importance in the areas of physics, chemistry and material science. Much effort has been devoted to the synthesis of TiO2 nanomaterials for various applications. Among them, mesoporous TiO2 materials, especially with hierarchically porous structures, show great potential owing to their extraordinarily high surface areas, large pore volumes, tunable pore structures and morphologies, and nanoscale effects. This review aims to provide an overview of the synthesis and applications of hierarchically mesoporous TiO2 materials. In the first section, the general synthetic strategies for hierarchically mesoporous TiO2 materials are reviewed. After that, we summarize the architectures of hierarchically mesoporous TiO2 materials, including nanofibers, nanosheets, microparticles, films, spheres, core-shell and multi-level structures. At the same time, the corresponding mechanisms and the key factors for the controllable synthesis are highlighted. Following this, the applications of hierarchically mesoporous TiO2 materials in terms of energy storage and environmental protection, including photocatalytic degradation of pollutants, photocatalytic fuel generation, photoelectrochemical water splitting, catalyst support, lithium-ion batteries and sodium-ion batteries, are discussed. Finally, we outline the challenges and future directions of research and development in this area.

scholarly journals Aminopropyl Functionalised MCM-41: Synthesis and Application for Adsorption of Pb(II) and Cd(II)

2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
Pham Dinh Du ◽  
Nguyen Trung Hieu ◽  
Thuy Chau To ◽  
Long Giang Bach ◽  
Mai Xuan Tinh ◽  
...  
Keyword(s):  
Indirect Method ◽  
Direct Method ◽  
Error Function ◽  
High Surface ◽  
Isotherm Models ◽  
Maximum Adsorption Capacity ◽  
Surface Areas ◽  
Paired Samples ◽  
Adsorption Desorption ◽  
Mcm 41

This paper shows a comparison of porous properties of aminopropyl-MCM-41 materials functionalised via the direct and indirect methods. The obtained materials were characterised using X-ray powder diffraction (XRD), transmission electron microscopy (TEM), thermogravimetric analysis-differential scanning calorimeter (TGA-DSC), adsorption/desorption isotherms of nitrogen, and Fourier-transfer infrared (FT-IR) spectroscopy. The results showed that the direct method provided the aminopropyl-MCM-41 material with well-ordered pores and high surface areas but with a lower quantity of grafted 3-aminopropyltriethoxysilane than the indirect method. To remove the organic template in the indirect method, solvent extraction with HCl/C2H5OH and calcination at 500°C were used, and the former gave a higher quantity of grafted 3-aminopropyltriethoxysilane in the resulting aminopropyl-MCM-41 materials. The experimental data were applied to the isotherm models of adsorption including Langmuir, Freundlich, Redlich–Peterson, and Sips either in the linear or nonlinear form. In order to avoid the bias of the determination coefficient and the error function method, the paired-samples t-test as an alternative method was first proposed to look for the most appropriate adsorption isotherms. The maximum adsorption capacity of Cd(II) and Pb(II) was 14.08 mg·g−1 and 64.21 mg·g−1, respectively. The mechanism of complexation and isoelectric interaction was suggested to explain the adsorption of Pb(II) and Cd(II) from aqueous solutions on aminopropyl functionalised MCM-41 in the range of pH from 2 to 9.

A Highly Crystalline Anthracene-Based MOF-74 Series Featuring Electrical Conductivity and Luminescence

2019 ◽  
Author(s):  
Patricia Scheurle ◽  
Andre Mähringer ◽  
Andreas Jakowetz ◽  
Pouya Hosseini ◽  
Alexander Richter ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Metal Ions ◽  
Light Emission ◽  
Block Design ◽  
High Surface ◽  
Visible Spectrum ◽  
Building Blocks ◽  
Divalent Metal Ions ◽  
Conductivity Enhancement ◽  
Surface Areas

Recently, a small group of metal-organic frameworks (MOFs) has been discovered featuring substantial charge transport properties and electrical conductivity, hence promising to broaden the scope of potential MOF applications in fields such as batteries, fuel cells and supercapacitors. In combination with light emission, electroactive MOFs are intriguing candidates for chemical sensing and optoelectronic applications. Here, we incorporated anthracene-based building blocks into the MOF-74 topology with five different divalent metal ions, that is, Zn2+, Mg2+, Ni2+, Co2+ and Mn2+, resulting in a series of highly crystalline MOFs, coined ANMOF-74(M). This series of MOFs features substantial photoluminescence, with ANMOF-74(Zn) emitting across the whole visible spectrum. The materials moreover combine this photoluminescence with high surface areas and electrical conductivity. Compared to the original MOF-74 materials constructed from 2,5-dihydroxy terephthalic acid and the same metal ions Zn2+, Mg2+, Ni2+, Co2+ and Mn2+, we observed a conductivity enhancement of up to six orders of magnitude. Our results point towards the importance of building block design and the careful choice of the embedded MOF topology for obtaining materials with desired properties such as photoluminescence and electrical conductivity.

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