scholarly journals Comparison of Structure and Adsorption Properties of Mesoporous Silica Functionalized with Aminopropyl Groups by the Co-Condensation and the Post Grafting Methods

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 628
Author(s):  
Ana-Maria Putz ◽  
Mihaela Ciopec ◽  
Adina Negrea ◽  
Oana Grad ◽  
Cătălin Ianăşi ◽  
...  
Keyword(s):  
Mesoporous Silica ◽  
High Surface ◽  
High Surface Area ◽  
Adsorption Properties ◽  
Amino Groups ◽  
X Ray ◽  
Functionalized Mesoporous Silica ◽  
X Ray Scattering ◽  
Post Synthesis ◽  
Grafting Methods

The adsorptive potential has been evaluated for the aminopropyl functionalized mesoporous silica materials obtained by co-condensation and post grafting methods. Nitrogen sorption, small angle neutron and X-ray scattering (SANS and SAXS) demonstrated high surface area and well-ordered hexagonal pore structure suitable for applications as adsorbents of metals from waste waters. A comparison of Cr(VI) adsorption properties of the materials prepared by different functionalization methods has been performed. The obtained results demonstrated the adsorption capacity due to the affinity of the chromium ions to the amino groups, and showed that co-condensation of tetraethoxysilane (TEOS) and 3-aminopropyl triethoxysilane (APTES) resulted in higher metal sorption capacity of the materials compared to post-synthesis grafting of aminopropyl groups onto the mesoporous silica particles.

Efficient Removal of Cd2+ by the Mesoporous Silica Functionalized by APTES

2013 ◽  
Vol 726-731 ◽  
pp. 2409-2412
Author(s):  
Xiao Feng Cai ◽  
Kang Wei Ji ◽  
Wan Hao Wu ◽  
Jie Hou ◽  
Shi You Hao
Keyword(s):  
Aqueous Solution ◽  
Mesoporous Silica ◽  
Ph Value ◽  
High Surface ◽  
High Surface Area ◽  
Efficient Removal ◽  
Structure Directing Agent ◽  
Functionalized Mesoporous Silica ◽  
Adsorption Desorption ◽  
Large Pore Size

Amino-functionalized mesoporous silica (AFMS) with high amino loading, high surface area, and large pore size was synthesized using the anionic surfactant N-lauroylsarcosine sodium (Sar-Na) as template and 3-aminopropyltriethoxysilane (APTES) as co-structure directing agent (CSDA). The synthesized AFMS was characterized by N2adsorption-desorption, TEM and elemental analyzer. The results of the removal of Cd2+from aqueous solution showed that the pH value of aqueous solution affected the removal efficiency of Cd2+greatly, and that unary adsorption isotherm of Cd2+on the AFMS was well described by the Sips isotherm model, in which the adsorption capacity was 2.43 mmol/g for Cd2+, much higher than the literature data.

Controlled Growth of Imine-Linked Two-Dimensional Covalent Organic Framework Nanoparticles

2019 ◽  
Author(s):  
Rebecca Li ◽  
Nathan C. Flanders ◽  
Austin Evans ◽  
Woojung Ji ◽  
Ioannina Castano ◽  
...  
Keyword(s):  
High Surface ◽  
High Surface Area ◽  
Particle Growth ◽  
Emergent Properties ◽  
Mechanistic Studies ◽  
X Ray ◽  
X Ray Scattering ◽  
Exchange Processes ◽  
And Control

Covalent organic frameworks (COFs) consist of monomers arranged in predictable structures with emergent properties. However, improved crystallinity, porosity, and solution processability remain major challenges. To this end, colloidal COF nanoparticles are useful for mechanistic studies of nucleation and growth and enable advanced spectroscopy and solution processing of thin films. Here we present a general approach to synthesize imine-linked 2D COF nanoparticles and control their size by favoring imine polymerization while preventing the nucleation of new particles. The method yields uniform, crystalline, and high-surface-area particles and is applicable to several imine-linked COFs. In situ X-ray scattering experiments reveal the nucleation of amorphous polymers, which crystallize via imine exchange processes during and after particle growth, consistent with previous mechanistic studies of imine-linked COF powders. The separation of particle formation and growth processes offers control of particle size and may enable further improvements in crystallinity in the future.

scholarly journals Robust Amino-Functionalized Mesoporous Silica Hollow Spheres Templated by CO2 Bubbles

Molecules ◽  
2021 ◽  
Vol 27 (1) ◽  
pp. 53
Author(s):  
Hongjuan Wang ◽  
Xuefei Liu ◽  
Olena Saliy ◽  
Wei Hu ◽  
Jingui Wang
Keyword(s):  
Mesoporous Silica ◽  
Condensation Reaction ◽  
High Surface ◽  
Hollow Spheres ◽  
High Surface Area ◽  
Production Costs ◽  
Hollow Structures ◽  
Functionalized Mesoporous Silica ◽  
Hollow Silica Spheres ◽  
Knoevenagel Condensation Reaction

Hollow-structured mesoporous silica has wide applications in catalysis and drug delivery due to its high surface area, large hollow space, and short diffusion mesochannels. However, the synthesis of hollow structures usually requires sacrificial templates, leading to increased production costs and environmental problems. Here, for the first time, amino-functionalized mesoporous silica hollow spheres were synthesized by using CO2 gaseous bubbles as templates. The assembly of anionic surfactants, co-structure directing agents, and inorganic silica precursors around CO2 bubbles formed the mesoporous silica shells. The hollow silica spheres, 200–400 nm in size with 20–30 nm spherical shell thickness, had abundant amine groups on the surface of the mesopores, indicating excellent applications for CO2 capture, Knoevenagel condensation reaction, and the controlled release of Drugs.

scholarly journals Preparation of Ammonia Dealuminated Metakaolinite and Its Adsorption against Bixin

2020 ◽  
Vol 20 (4) ◽  
pp. 791
Author(s):  
Winda Rahmalia ◽  
Jean-Francois Fabre ◽  
Thamrin Usman ◽  
Zéphirin Mouloungui
Keyword(s):  
Surface Area ◽  
Room Temperature ◽  
High Surface ◽  
High Surface Area ◽  
Total Pore Volume ◽  
Adsorption Properties ◽  
Order Kinetic ◽  
X Ray Diffraction ◽  
X Ray ◽  
Pseudo Second Order

This study aims to prepare dealuminated metakaolinite which has a high surface area by using NH4OH as an activator. The natural kaolinite sample was treated at 600 °C for 6 h in order to obtain metakaolinite. A dealuminated metakaolinite was then prepared by the repeated activation method using concentrated ammonia (5 M NH4OH) at room temperature. Depending on the nature of each type of material, natural kaolinite, NH4OH treated kaolinite, metakaolinite and NH4OH treated metakaolinite were characterized using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS), and Brunauer-Emmett-Teller (BET-N2) measurements. XRD and FTIR results confirmed that structural transformation from kaolinite to metakaolinite had occurred. According to SEM-EDS data, the activation of metakaolinite by NH4OH allowed the dealumination of metakaolinite. The increase in the Si/Al ratio was almost twice as high as in kaolinite. BET-N2 analysis showed that the specific surface area and the total pore volume increased significantly after activation. Its adsorption properties were tested against bixin. Bixin adsorption on dealuminated metakaolinite followed pseudo-second order kinetic where k2 = 0.20 g/mg min. The adsorption isotherm followed the Langmuir model where qm = 0.72 mg/g.

scholarly journals Folic Acid/Methotrexate Functionalized Mesoporous Silica Nanoflakes from Different Supports: Comparative Study

2020 ◽  
Vol 10 (18) ◽  
pp. 6465
Author(s):  
Martyna Trukawka ◽  
Krzysztof Cendrowski ◽  
Wojciech Konicki ◽  
Ewa Mijowska
Keyword(s):  
Drug Delivery ◽  
Folic Acid ◽  
Mesoporous Silica ◽  
Drug Delivery Systems ◽  
High Surface ◽  
High Surface Area ◽  
Physicochemical Characterization ◽  
Delivery Systems ◽  
Functionalized Mesoporous Silica ◽  
Low Cytotoxicity

Herein, we present a facile synthesis route for the mesoporous silica nanoflakes on two types of templates and evaluate their potential as potential drug delivery systems. Silica materials are attractive due to their biocompatibility, low cytotoxicity, high surface area, and tunable pores. In addition, they can be multifunctionalized. These properties were used to create multifunctional drug delivery systems combining folic acid as a target molecule and methotrexate (MTX) as an anticancer drug. The silica nanoflakes were formed using graphene oxide and double-layered hydroxide as templates, respectively. After the removal of matrices, the silica flakes were functionalized by folic acid and loaded with methotrexate. The differences in drug release performance and structural stability were analyzed with respect to the detailed physicochemical characterization of the produced silica nanoflakes.

Controlled Growth of Imine-Linked Two-Dimensional Covalent Organic Framework Nanoparticles

2019 ◽  
Author(s):  
Rebecca Li ◽  
Nathan C. Flanders ◽  
Austin Evans ◽  
Woojung Ji ◽  
Ioannina Castano ◽  
...  
Keyword(s):  
High Surface ◽  
High Surface Area ◽  
Particle Growth ◽  
Emergent Properties ◽  
Mechanistic Studies ◽  
X Ray ◽  
X Ray Scattering ◽  
Exchange Processes ◽  
And Control

Covalent organic frameworks (COFs) consist of monomers arranged in predictable structures with emergent properties. However, improved crystallinity, porosity, and solution processability remain major challenges. To this end, colloidal COF nanoparticles are useful for mechanistic studies of nucleation and growth and enable advanced spectroscopy and solution processing of thin films. Here we present a general approach to synthesize imine-linked 2D COF nanoparticles and control their size by favoring imine polymerization while preventing the nucleation of new particles. The method yields uniform, crystalline, and high-surface-area particles and is applicable to several imine-linked COFs. In situ X-ray scattering experiments reveal the nucleation of amorphous polymers, which crystallize via imine exchange processes during and after particle growth, consistent with previous mechanistic studies of imine-linked COF powders. The separation of particle formation and growth processes offers control of particle size and may enable further improvements in crystallinity in the future.

scholarly journals Synthesis of high surface area mesoporous silica SBA-15 by adjusting hydrothermal treatment time and the amount of polyvinyl alcohol

2019 ◽  
Vol 17 (1) ◽  
pp. 963-971
Author(s):  
Ridhawati Thahir ◽  
Abdul Wahid Wahab ◽  
Nursiah La Nafie ◽  
Indah Raya
Keyword(s):  
Mesoporous Silica ◽  
Surface Area ◽  
Hydrothermal Treatment ◽  
Pore Volume ◽  
Pore Diameter ◽  
High Surface ◽  
High Surface Area ◽  
Diffraction Measurement ◽  
X Ray Diffraction ◽  
X Ray

AbstractThe high surface area of mesoporous silica SBA-15 has been synthesized successfully by hydrothermal treatment with direct addition of PVA, triblock copolymer (P123) as a direct structure agent and tetraethyl orthosilicate (TEOS) as a precursor. The mesoporous silica SBA-15 have been characterized with nitrogen physisorption, scanning electron microscopy, Fourier transformed infrared spectroscopy, and x-ray diffraction. Measurement of nitrogen sorption indicated that with the addition of PVA, the surface area is increased but the pore volume and pore diameter is not significantly. The short time of hydrothermal treatment (20 h) and using x-ray diffraction, showed that the morphological structure of silica SBA-15 can be changed to a orthorhombic crystal system. The result of the FTIR and SEM-EDX characteristic indicated the functional groups and morphology of the SBA-15 with a narrow pore size distribution. The BET method has exhibited the largest surface area 1726 m2/g, pore volume 1.4 cm3/g, and pore diameter 3.2 nm. It can be suggested that the silica mesoporous SBA-15 will have potential application prospect in catalysis, storage, and adsorbent.

scholarly journals Recent Advances in Functionalized Mesoporous Silica Frameworks for Efficient Desulfurization of Fuels

Nanomaterials ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 1116 ◽  
Author(s):  
Shruti Mendiratta ◽  
Ahmed Atef Ahmed Ali
Keyword(s):  
Mesoporous Silica ◽  
Sulfur Content ◽  
Active Sites ◽  
Fossil Fuels ◽  
High Surface ◽  
High Surface Area ◽  
Sulfur Removal ◽  
Jet Fuels ◽  
High Porosity ◽  
Functionalized Mesoporous Silica

Considerable health and climate benefits arising from the use of low-sulfur fuels has propelled the research on desulfurization of fossil fuels. Ideal fuels are urgently needed and are expected to be ultra-low in sulfur (10–15 ppm), with no greater than 50 ppm sulfur content. Although several sulfur removal techniques are available in refineries and petrochemical units, their high operational costs, complex operational needs, low efficiencies, and higher environmental risks render them unviable and challenging to implement. In recent years, mesoporous silica-based materials have emerged as promising desulfurizing agents, owing to their high porosity, high surface area, and easier functionalization compared to conventional materials. In this review, we report on recent progress in the synthesis and chemistry of new functionalized mesoporous silica materials aiming to lower the sulfur content of fuels. Additionally, we discuss the role of special active sites in these sorbent materials and investigate the formulations capable of encapsulating and trapping the sulfur-based molecules, which are challenging to remove due to their complexity, for example the species present in JP-8 jet fuels.

scholarly journals Non-Thermal Plasma-Modified Ru-Sn-Ti Catalyst for Chlorinated Volatile Organic Compound Degradation

Catalysts ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1456
Author(s):  
Yujie Fu ◽  
You Zhang ◽  
Qi Xin ◽  
Zhong Zheng ◽  
Yu Zhang ◽  
...  
Keyword(s):  
Plasma Treatment ◽  
Photoelectron Spectroscopy ◽  
High Surface ◽  
High Surface Area ◽  
Surface Oxidation ◽  
Treatment Method ◽  
X Ray ◽  
Chlorinated Volatile Organic Compounds ◽  
Volatile Organic ◽  
Doped Titania

Chlorinated volatile organic compounds (CVOCs) are vital environmental concerns due to their low biodegradability and long-term persistence. Catalytic combustion technology is one of the more commonly used technologies for the treatment of CVOCs. Catalysts with high low-temperature activity, superior selectivity of non-toxic products, and resistance to chlorine poisoning are desirable. Here we adopted a plasma treatment method to synthesize a tin-doped titania loaded with ruthenium dioxide (RuO2) catalyst, possessing enhanced activity (T90%, the temperature at which 90% of dichloromethane (DCM) is decomposed, is 262 °C) compared to the catalyst prepared by the conventional calcination method. As revealed by transmission electron microscopy, X-ray diffraction, N2 adsorption, X-ray photoelectron spectroscopy, and hydrogen temperature-programmed reduction, the high surface area of the tin-doped titania catalyst and the enhanced dispersion and surface oxidation of RuO2 induced by plasma treatment were found to be the main factors determining excellent catalytic activities.

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