scholarly journals Microwave Synthesis of MCM-41 and Its Application in CO2 Absorption by Nanofluids

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Shang-Yuan Cheng ◽  
You-Zhi Liu ◽  
Gui-Sheng Qi
Keyword(s):  
Microwave Synthesis ◽  
Active Sites ◽  
Synthesis Method ◽  
Average Diameter ◽  
Narrow Particle Size Distribution ◽  
Enhancement Effect ◽  
Co2 Absorption ◽  
Enhanced Absorption ◽  
Microwave Time ◽  
Mcm 41

Microwave synthesis method is a green chemical process with mild reaction conditions, fast reaction, and low energy consumption. In this work, an order mesoporous silica material MCM-41 was synthesized by microwave technology. Functionalized MCM-41 was prepared by wet impregnation with polyethyleneimine (PEI). XRD, SEM, TEM, DLS, N2 adsorption-desorption, FTIR, and TG were used to characterize the physicochemical properties of samples. Furthermore, CO2 absorption performance in water in the presence of uncalcined MCM-41 and PEI-MCM-41 nanoparticles was evaluated. In addition, the mechanisms of enhanced absorption were also elaborated. The experimental results indicated that the optimum conditions for preparation of MCM-41 were the microwave time of 15 min, microwave temperature of 100°C, and microwave power of 200 W. Under this condition, MCM-41 with narrow particle size distribution, average diameter of 50 nm, and SBET of 1210.3 m2g-1 was obtained. The enhancement effect of PEI-MCM-41 nanoparticles was more obvious than that of uncalcined MCM-41. PEI-MCM-41 as a promoter not only increased the CO2 diffusion rate but also enhanced the adsorption capacity due to the fact that it owns more active sites that may react with CO2. The CO2 absorption improvement of PEI-MCM-41 (0.1 wt%)/H2O was 25.35% higher than that of water.

The design and catalytic performance of molybdenum active sites on an MCM-41 framework for the aerobic oxidation of 5-hydroxymethylfurfural to 2,5-diformylfuran

2019 ◽  
Vol 9 (3) ◽  
pp. 811-821 ◽  
Author(s):  
Zhao-Meng Wang ◽  
Li-Juan Liu ◽  
Bo Xiang ◽  
Yue Wang ◽  
Ya-Jing Lyu ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Active Sites ◽  
Aerobic Oxidation ◽  
Catalytic Performance ◽  
Mcm 41

The catalytic activity decreases as –(SiO)3Mo(OH)(O) > –(SiO)2Mo(O)2 > –(O)4–MoO.

scholarly journals Construction of Chitosan/Alginate Nano-Drug Delivery System for Improving Dextran Sodium Sulfate-Induced Colitis in Mice

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1884
Author(s):  
Mengfei Jin ◽  
Shangyong Li ◽  
Yanhong Wu ◽  
Dandan Li ◽  
Yantao Han
Keyword(s):  
Self Assembly ◽  
Average Diameter ◽  
Mucosal Healing ◽  
Plga Nanoparticles ◽  
Narrow Particle Size Distribution ◽  
Layer By Layer ◽  
Systemic Side Effects ◽  
Assembly Technology ◽  
The Fourier Transform ◽  
Polyelectrolyte Film

(1) Background: In the treatment of ulcerative colitis (UC), accurate delivery and release of anti-inflammatory drugs to the site of inflammation can reduce systemic side effects. (2) Methods: We took advantage of this goal to prepare resveratrol-loaded PLGA nanoparticles (RES-PCAC-NPs) by emulsification solvent volatilization. After layer-by-layer self-assembly technology, we deposited chitosan and alginate to form a three-layer polyelectrolyte film. (3) Results: It can transport nanoparticles through the gastric environment to target inflammation sites and slowly release drugs at a specific pH. The resulting RES-PCAC-NPs have an ideal average diameter (~255 nm), a narrow particle size distribution and a positively charged surface charge (~13.5 mV). The Fourier transform infrared spectroscopy showed that resveratrol was successfully encapsulated into PCAC nanoparticles, and the encapsulation efficiency reached 87.26%. In addition, fluorescence imaging showed that RES-PCAC-NPs with positive charges on the surface can effectively target and accumulate in the inflammation site while continuing to penetrate downward to promote mucosal healing. Importantly, oral RES-PCAC-NPs treatment in DSS-induced mice was superior to other results in significantly improved inflammatory markers of UC. (4) Conclusions: Our results strongly prove that RES-PCAC-NPs can target the inflamed colon for maximum efficacy, and this oral pharmaceutical formulation can represent a promising formulation in the treatment of UC.

scholarly journals Silica Monolith for the Removal of Pollutants from Gas and Aqueous Phases

Molecules ◽  
2021 ◽  
Vol 26 (5) ◽  
pp. 1316
Author(s):  
Vanessa Miglio ◽  
Chiara Zaccone ◽  
Chiara Vittoni ◽  
Ilaria Braschi ◽  
Enrico Buscaroli ◽  
...  
Keyword(s):  
Rhodamine B ◽  
Water Solution ◽  
Synthesis Method ◽  
Textural Properties ◽  
Adsorption Properties ◽  
Water Soluble ◽  
Silica Monoliths ◽  
Physico Chemical ◽  
Gaseous Toluene ◽  
Mcm 41

This study focused on the application of mesoporous silica monoliths for the removal of organic pollutants. The physico-chemical textural and surface properties of the monoliths were investigated. The homogeneity of the textural properties along the entire length of the monoliths was assessed, as well as the reproducibility of the synthesis method. The adsorption properties of the monoliths for gaseous toluene, as a model of Volatile Organic Compounds (VOCs), were evaluated and compared to those of a reference meso-structured silica powder (MCM-41) of commercial origin. Silica monoliths adsorbed comparable amounts of toluene with respect to MCM-41, with better performances at low pressure. Finally, considering their potential application in water phase, the adsorption properties of monoliths toward Rhodamine B, selected as a model molecule of water soluble pollutants, were studied together with their stability in water. After 24 h of contact, the silica monoliths were able to adsorb up to the 70% of 1.5 × 10−2 mM Rhodamine B in water solution.

scholarly journals Non-Isothermal Decomposition as Efficient and Simple Synthesis Method of NiO/C Nanoparticles for Asymmetric Supercapacitors

Nanomaterials ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 187
Author(s):  
Daria Chernysheva ◽  
Ludmila Pudova ◽  
Yuri Popov ◽  
Nina Smirnova ◽  
Olga Maslova ◽  
...  
Keyword(s):  
Nickel Oxide ◽  
Synthesis Method ◽  
Average Diameter ◽  
Carbon Support ◽  
Spherical Particles ◽  
Support Surface ◽  
Isothermal Decomposition ◽  
Step Method ◽  
Nickel Oxide Nanoparticles ◽  
Electrode Cell

A series of NiO/C nanocomposites with NiO concentrations ranging from 10 to 90 wt% was synthesized using a simple and efficient two-step method based on non-isothermal decomposition of Nickel(II) bis(acetylacetonate). X-ray diffraction (XRD) measurements of these NiO/C nanocomposites demonstrate the presence of β-NiO. NiO/C nanocomposites are composed of spherical particles distributed over the carbon support surface. The average diameter of nickel oxide spheres increases with the NiO content and are estimated as 36, 50 and 205 nm for nanocomposites with 10, 50 and 80 wt% NiO concentrations, respectively. In turn, each NiO sphere contains several nickel oxide nanoparticles, whose average sizes are 7–8 nm. According to the tests performed using a three-electrode cell, specific capacitance (SC) of NiO/C nanocomposites increases from 200 to 400 F/g as the NiO content achieves a maximum of 60 wt% concentration, after which the SC decreases. The study of the NiO/C composite showing the highest SC in three- and two-electrode cells reveals that its SC remains almost unchanged while increasing the current density, and the sample demonstrates excellent cycling stability properties. Finally, NiO/C (60% NiO) composites are shown to be promising materials for charging quartz clocks with a power rating of 1.5 V (30 min).

Application of Microwave Radiation in Modified Polyol Process for Synthesis Pure, Te-Doped, and Sn-Doped CoSb3 Thermoelectric Materials

2020 ◽  
Vol 302 ◽  
pp. 123-134
Author(s):  
Thammanoon Kapanya ◽  
Chanchana Thanachayanont ◽  
Adisorn Tuantranont ◽  
Thapanee Sarakonsri
Keyword(s):  
Electron Microscope ◽  
Microwave Radiation ◽  
Crystalline Phase ◽  
Synthesis Method ◽  
Normal Pressure ◽  
Solubility Limit ◽  
Heating Time ◽  
Polyol Process ◽  
Transmission Electron ◽  
Microwave Time

Synthesis routes of CoSb3 need a long reaction time, especially at high temperature and-/or high pressure. Although the modified polyol process assisted with microwave radiation can be used to solve these problems, it used the excess amount of Sb ion. Therefore, this study aimed to solve this drawback by retarding the rate of reduction. The different microwave times (0, 1, and 3 min) were investigated to find out the shortest heating duration for preparing CoSb3 nanoparticles. Te-doped and Sn-doped CoSb3 were synthesized to investigate the benefit of this synthesis method for increasing the solubility limit of Te and Sn in the CoSb3 structure. The phase and microstructure of the synthesized products were characterized by using x-ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscope (TEM). The results showed that the high crystalline phase of CoSb3 (JCPDS: 78-0977) without any metallic impurity phases product was successfully synthesized in 3 minutes for a heating time at normal pressure, non-excessive addition of Sb ion precursor, and low temperature. The XRD results of Te-doped and Sn-doped CoSb3 products exhibited poor crystalline phase and hard to exactly identify. In SEM and TEM results, the CoSb3 powder consisted of very tiny spherical-like particles around 10 nanometers attaching together even at different microwave time similar to Te-doped/Sn-doped samples.

Drug release profiles of modified MCM-41 with superparamagnetic behavior correlated with the employed synthesis method

2017 ◽  
Vol 78 ◽  
pp. 674-681 ◽  
Author(s):  
Natalia I. Cuello ◽  
Verónica R. Elías ◽  
Silvia N. Mendieta ◽  
Marcela Longhi ◽  
Mónica E. Crivello ◽  
...  
Keyword(s):  
Drug Release ◽  
Synthesis Method ◽  
Superparamagnetic Behavior ◽  
Mcm 41 ◽  
Release Profiles

Acidity and active sites of Al-MCM-41

1999 ◽  
Vol 184 (1) ◽  
pp. 49-60 ◽  
Author(s):  
H Kosslick ◽  
G Lischke ◽  
B Parlitz ◽  
W Storek ◽  
R Fricke
Keyword(s):  
Active Sites ◽  
Mcm 41

scholarly journals Highly Selective Au/ZnO via Colloidal Deposition for CO2 Hydrogenation to Methanol: Evidence of AuZn Role

2021 ◽  
Vol 16 (1) ◽  
pp. 44-51
Author(s):  
Hasliza Bahruji ◽  
Mshaal Almalki ◽  
Norli Abdullah
Keyword(s):  
Active Sites ◽  
Au Nanoparticles ◽  
High Selectivity ◽  
Average Diameter ◽  
Co2 Hydrogenation ◽  
Impregnation Method ◽  
Co2 Conversion ◽  
Methanol Production ◽  
Surface Oxygen Vacancy ◽  
Colloidal Method

Gold, Au nanoparticles were deposited on ZnO, Al2O3, and Ga2O3 via colloidal method in order to investigate the role of support for CO2 hydrogenation to methanol. Au/ZnO was also produced using impregnation method to investigate the effect of colloidal method to improve methanol selectivity. Au/ZnO produced via sol immobilization showed high selectivity towards methanol meanwhile impregnation method produced Au/ZnO catalyst with high selectivity towards CO. The CO2 conversion was also influenced by the amount of Au weight loading. Au nanoparticles with average diameter of 3.5 nm exhibited 4% of CO2 conversion with 72% of methanol selectivity at 250 °C and 20 bar. The formation of AuZn alloy was identified as active sites for selective CO2 hydrogenation to methanol. Segregation of Zn from ZnO to form AuZn alloy increased the number of surface oxygen vacancy for CO2 adsorption to form formate intermediates. The formate was stabilized on AuZn alloy for further hydrogenation to form methanol.  The use of Al2O3 and Ga2O3 inhibited the formation of Au alloy, and therefore reduced methanol production. Au/Al2O3 showed 77% selectivity to methane, meanwhile Au/Ga2O3 produced 100% selectivity towards CO. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0). 

scholarly journals Synthesis and Infrared Performance of SiB6 Powder through “Chemical Oven” Self-Propagating Combustion

2021 ◽  
Vol 2021 ◽  
pp. 1-6
Author(s):  
Shuang Shuang ◽  
Fengxia Yang ◽  
Zhiwei Li ◽  
Jiangtao Li ◽  
Xiangmin Meng
Keyword(s):  
Near Infrared ◽  
Integral Intensity ◽  
Synthesis Method ◽  
Average Diameter ◽  
Raw Material ◽  
Infrared Range ◽  
Severe Condition ◽  
Molar Ratios ◽  
Whole Process ◽  
Maximum Reaction

SiB6 powders were prepared by the “chemical oven” method from Si and B powders. Here combustion with acid pickling “two-step” mode replaces the traditional synthesis method which helps to avoid severe condition of high temperature and high pressure. It could realize maximum reaction temperature to about 2000°C, and the whole process just needs ∼30 s. The average diameter of products is ∼10 μm. And the raw material Si and B are ∼3 μm and ∼20 μm, respectively. The infrared emissivity of products was evaluated by UV-vis spectrum with absorption band around 250∼2500 nm. All five samples show higher emissivity over UV-visible light range with lower emissivity over near-infrared range. Typically, the sample’s Si/B ratio of 1 : 1 shows highest integral intensity for about 0.85 compared with other molar ratios. It can be used as a more simple and effective method to obtain infrared ceramic SiB6 with high emissivity.

Preparation and characterization of poly(styrenemethacrylic acid)/MCM-41 core/shell nanocomposite microspheres

e-Polymers ◽  
2009 ◽  
Vol 9 (1) ◽  
Author(s):  
Yansheng Zhao ◽  
Xingji Ma ◽  
Yongmei Liu ◽  
Guangwei Yuan ◽  
Meijuan Guo ◽  
...  
Keyword(s):  
Self Assembly ◽  
Cetyltrimethylammonium Bromide ◽  
Average Diameter ◽  
Molar Ratio ◽  
Core Shell ◽  
Acidic Media ◽  
Assembly Method ◽  
20 Nm ◽  
Mcm 41

AbstractIn acidic media, poly(styrene-methacrylic acid)/MCM-41 [P(St- MAA)/MCM-41] core/shell microspheres were synthesized using monodisperse P(St-MAA) particles contained in soap-free emulsion and cetyltrimethylammonium bromide as co-templates by adsorption self-assembly method. The effects of P(St- MAA) composition on shell structure of the core/shell microspheres were investigated. The morphology and composition of P(St-MAA)/MCM-41 microspheres were characterized by TEM, XRD and FTIR. The results show that the ordering degree of MCM-41 shells increased as the molar ratio of MAA to St increased. When n(MAA)/n(St) is 0.2, the average diameter and the shell thickness of nanocomposite microspheres are about 170 nm and 20 nm, respectively.

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