Synthesis of Smart Mesoporous Materials

2003 ◽  
Vol 775 ◽  
Author(s):  
G.V.Rama Rao ◽  
Qiang Fu ◽  
Linnea K. Ista ◽  
Huifang Xu ◽  
S. Balamurugan ◽  
...  

AbstractThis study details development of hybrid mesoporous materials in which molecular transport through mesopores can be precisely controlled and reversibly modulated. Mesoporous silica materials formed by surfactant templating were modified by surface initiated atom transfer radical polymerization of poly(N-isopropyl acrylamide) (PNIPAAm) a stimuli responsive polymer (SRP) within the porous network. Thermo gravimetric analysis and FTIR spectroscopy were used to confirm the presence of PNIPAAm on the silica surface. Nitrogen porosimetry, transmission electron microscopy and X-ray diffraction analyses confirmed that polymerization occurred uniformly within the porous network. Uptake and release of fluorescent dyes from the particles was monitored by spectrofluorimetry and scanning laser confocal microscopy. Results suggest that the presence of PNIPAAm, a SRP, in the porous network can be used to modulate the transport of aqueous solutes. At low temperature, (e.g., room temperature) the PNIPAAm is hydrated and extended and inhibits transport of analytes; at higher temperatures (e.g., 50°C) it is hydrophobic and is collapsed within the pore network, thus allowing solute diffusion into or out of the mesoporous silica. The transition form hydrophilic to hydrophobic state on polymer grafted mesoporous membranes was determined by contact angle measurements. This work has implications for the development of materials for the selective control of transport of molecular solutes in a variety of applications.

2021 ◽  
Author(s):  
Ahmed Wasel Alsmaeil ◽  
Mohamed Amen Hammami ◽  
Amr Ismail Abdel-Fattah ◽  
Mazin Yousef Kanj ◽  
Emmanuel P Giannelis

Abstract Developing nanocarriers deliver molecules to targeted locations has received widespread attention in different fields ranging from biomedical to oil and gas industries. Mesoporous Silica Nanoparticles (MSNs), where the pore size diameter ranges from 2-50 nm, have become attractive in many fields including biomedicine. One advantage is the ability to control the size, morphology of the particles, and the internal and external surfaces properties which enable encapsulating molecules of different size and charges. Moreover, it is possible to functionalize the pores and the surface of the MSNs, which make them suitable to host different molecules and release them in situ in a controlled manner. Despite the numerous studies of MSNs, little has been devoted to subsurface applications. This review will highlight some of the interesting characteristics of MSNs that make them promising carriers of molecules for slow and/or stimuli-responsive delivery for oil field applications. For example, they could be utilized for the controlled release of surfactants for enhanced oil recovery applications to minimize surfactant losses near the well-bore area. The mesoporous materials can be designed to harvest the ions normally present in oil field water, and the high temperatures encountered when travelling deep in the reservoir to release the surfactant. The ion exchange process makes it possible to engineer the MSNs to release their cargo for efficient and stimuli responsive delivery applications. The ion-responsive release was analyzed by the interfacial tension behavior between crude oil and high salinity water (HSW). It is concluded that the interfacial tension could be reduced up to 0.0045 mN/m when the mesoporous silica particles are suspended in HSW in comparison to 0.9 mN/m when suspended in DI water.


2003 ◽  
Vol 15 (15) ◽  
pp. 1262-1266 ◽  
Author(s):  
Q. Fu ◽  
G.V.R. Rao ◽  
L.K. Ista ◽  
Y. Wu ◽  
B.P. Andrzejewski ◽  
...  

2007 ◽  
Vol 124-126 ◽  
pp. 1717-1720 ◽  
Author(s):  
Sun Sang Kwon ◽  
Sang Hoon Jeon ◽  
Jeong Kuk Shon ◽  
Duck Hee Kim ◽  
Ih Seop Chang ◽  
...  

To improve lipase activity and make the particulate carrier for practical application, lipase was conjugated to chitosan(Mwavg=80,000) by immine reaction. The lipase activity of conjugate was 93% of its initial activity at room temperature for 7 months, whereas the intact lipase activity decreased to 40%. And then, lipase-chitosan conjugate was intercalated within porous silica. The composite was characterized by X-ray diffraction, scanning electron microscopy, thermo gravimetric analysis. The Pore size was regulated in the range of 5~15nm. The maximum enzyme activity of lipase-chitosan conjugate needs the structure with 15nm pore of mesoporous silica. The resultant composite was found to have the free flowing property and keep up inner lipase activity.


Pharmaceutics ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 2033
Author(s):  
Elena Álvarez ◽  
Blanca González ◽  
Daniel Lozano ◽  
Antonio L. Doadrio ◽  
Montserrat Colilla ◽  
...  

This review focuses on the design of mesoporous silica nanoparticles for infection treatment. Written within a general context of contributions in the field, this manuscript highlights the major scientific achievements accomplished by professor Vallet-Regí’s research group in the field of silica-based mesoporous materials for drug delivery. The aim is to bring out her pivotal role on the envisage of a new era of nanoantibiotics by using a deep knowledge on mesoporous materials as drug delivery systems and by applying cutting-edge technologies to design and engineer advanced nanoweapons to fight infection. This review has been divided in two main sections: the first part overviews the influence of the textural and chemical properties of silica-based mesoporous materials on the loading and release of antibiotic molecules, depending on the host–guest interactions. Furthermore, this section also remarks on the potential of molecular modelling in the design and comprehension of the performance of these release systems. The second part describes the more recent advances in the use of mesoporous silica nanoparticles as versatile nanoplatforms for the development of novel targeted and stimuli-responsive antimicrobial nanoformulations for future application in personalized infection therapies.


2011 ◽  
Vol 356-360 ◽  
pp. 373-381
Author(s):  
Jin Huang ◽  
Meng Ye ◽  
Rui Chen ◽  
Qi Zhuang He

Novel Schiff base-functionalized SBA-15 mesoporous silica is prepared, characterized and used as an adsorbent for heavy metal ion, Cu (II). The organic-inorganic hybrid mesoporous materials have been synthesized by two post-graftings of tetraethoxysilane (TEOS) with 3-aminopropyltrimethoxy-silane (APTES) and salicylaldehyde in sequence. The functionalized mesoporous materials are characterized by means of X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM) and nitrogen (N2) adsorption-desorption analysis. The result indicates that, after sequent chemical modifications of aminopropyl and schiff base, the primary hexagonally ordered mesoporous structure of SBA-15 is not affected. The mesoporous silica, which has a BET surface area of 573.263 m2g-1, a high pore diameter (centered at 5.24 nm) and pore volume of 0.847 cm3 g-1, exhibits the excellent adsorption capacity. The removal rate of Cu2+in aqueous media is high and the adsorbent can be regenerated by EDTA and acid treatments without changing its properties.


2008 ◽  
Vol 59 (7) ◽  
Author(s):  
Madalina Angelusiu ◽  
Maria Negoiu ◽  
Stefania-Felicia Barbuceanu ◽  
Tudor Rosu

The paper presents the synthesis and characterization of Cu(II), Co(II), Ni(II), Cd(II), Zn(II) and Hg(II) complexes with N1-[4-(4-bromo-phenylsulfonyl)-benzoyl]-N4-(4-methoxyphenyl)-thiosemicarbazide. The new compounds were characterized by IR, EPR, electronic spectroscopy, magnetic moments, thermo-gravimetric analysis and elemental analysis.


2020 ◽  
Vol 13 ◽  
Author(s):  
Inbasekaran S. ◽  
G. Thiyagarajan ◽  
Ramesh C. Panda ◽  
S. Sankar

Background:: Chrome shavings, a bioactive material, are generated from tannery as waste material. These chrome shaving can be used for the preparation of many value-added products. Objective:: One such attempt is made to use these chrome shaving wastes as a composite bio-battery to produce DC voltage, an alternate green energy source and cleaner technology. Methods:: Chrome shavings are hydrolyzed to make collagen paste and mixed with the ferrous nanoparticles of Moringa oleifera leaves and Carbon nanoparticles of Onion peels to form electrolyte paste as base. Then, the electrolyte base was added to the aluminum paste and conducting gel, and mixed well to form composite material for bio-battery. Results:: The composite material of bio-battery has been characterized using Scanning Electron Microscopy (SEM), Fourier-Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC) and Thermo Gravimetric Analysis (TGA). Series and parallel circuit testing were done using Copper and Zinc electrodes or Carbon and Zinc electrodes as the battery terminals in the electrolyte paste. The surface area of these electrodes needs standardization from bench to pilot scale. The power generated, for an AA battery size, using a single bio-battery cell has produced a DC voltage of 1.5 V; current of 900 mA. Circuit testing on 1 ml of 80 well-cells connected in series has produced DC output of 18 V and 1100 mA whereas 48 V and 1500 mA were obtained from a series-parallel connection. Conclusion:: The glass transition temperature (Tg) of electrolyte of the bio-battery at 53°C indicates that, at this temperature, all the substances present in the bio-battery are well spread and contributing consistently to the electrolyte activity where Fe-C-Nano-Particles were able to form strong chemical bonds on the flanking hydroxyl group sites of the Collagen leading to reduced mobility of polymers and increase Tg. The results instigate promising trends for commercial exploitation of this composite for bio-battery production.


2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Luqman Ali Shah ◽  
Rida Javed ◽  
Mohammad Siddiq ◽  
Iram BiBi ◽  
Ishrat Jamil ◽  
...  

AbstractThe in-situ stabilization of Ag nanoparticles is carried out by the use of reducing agent and synthesized three different types of hydrogen (anionic, cationic, and neutral) template. The morphology, constitution and thermal stability of the synthesized pure and Ag-entrapped hybrid hydrogels were efficiently confirmed using scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) and thermo gravimetric analysis (TGA). The prepared hybrid hydrogels were used in the decolorization of methylene blue (MB) and azo dyes congo red (CR), methyl Orange (MO), and reduction of 4-nitrophenol (4-NP) and nitrobenzene (NB) by an electron donor NaBH4. The kinetics of the reduction reaction was also assessed to determine the activation parameters. The hybrid hydrogen catalysts were recovered by filtration and used continuously up to six times with 98% conversion of pollutants without substantial loss in catalytic activity. It was observed that these types of hydrogel systems can be used for the conversion of pollutants from waste water into useful products.


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