scholarly journals Experiences with Sol-Gel Bonded High Porosity Alumina Fiber Materials for Filter Applications

1988 ◽  
Vol 121 ◽  
Author(s):  
Karin E. Handrick ◽  
August Mohlratzer ◽  
Rolf Ostertag ◽  
Dieter Sporn ◽  
Helmut Schmidt
Keyword(s):  
Gas Flow ◽  
Porous Alumina ◽  
Sol Gel ◽  
High Porosity ◽  
Alumina Fiber ◽  
Gas Filtration ◽  
Ceramic Binder ◽  
Sol Gel Process ◽  
Fiber Materials ◽  
The Stability

ABSTRACTHigh porous alumina fiber structures appear promising for hot gas filtration in particular for diesel particulate traps. For this purpose, however, a method is required for manufacturing of stable shapes resistant to the blow-out by the gas flow. The sol-gel-process was expected to be the best suited method for fiber bonding to provide the required stability.The main tasks of the development-work were a uniform isotropie fiber-distribution, the adaptation of the sol-gel-process to the application, and the deliberate synthesis of the gel-derived alumina bonding phase.The appropriate fibrous structure was obtained by a repeated filtration of sol/fiber suspensions. The properties of the ceramic binder were adapted by concentrating the sol and/or adding aluminas or aluminium hydroxides.Testing of prototypes with optimized structures has shown, however, that the stability of the structure decreased after thermal load. The thermal fatigue of x-A12O3 is assumed to be responsible for this failure.

UV Curable Organic-Inorganic Hybrid Materials

2000 ◽  
Vol 628 ◽  
Author(s):  
Guang-Way Jang ◽  
Ren-Jye Wu ◽  
Yuung-Ching Sheen ◽  
Ya-Hui Lin ◽  
Chi-Jung Chang
Keyword(s):  
Hybrid Materials ◽  
Colloidal Silica ◽  
Sol Gel ◽  
Solution Ph ◽  
Uv Curable ◽  
Inorganic Hybrid ◽  
Degradation Temperature ◽  
Sol Gel Process ◽  
The Stability ◽  
Thermal Degradation Temperature

This work successfully prepared an UV curable organic-inorganic hybrid material consisting of organic modified colloidal silica. Applications of UV curable organic-inorganic hybrid materials include abrasion resistant coatings, photo-patternable thin films and waveguides. Colloidal silica containing reactive functional groups were also prepared by reacting organic silane and tetraethyl orthosilicate (TEOS) using sol-gel process. In addition, the efficiency of grafting organic moiety onto silica nanoparticles was investigated by applying TGA and FTIR techniques. Experimental results indicated a strong interdependence between surface modification efficiency and solution pH. Acrylate-SiO2 hybrid formation could result in a shifting of thermal degradation temperature of organic component from about 200°C to near 400°C. In addition, the stability of organic modified colloidal silica in UV curable formula and the physical properties of resulting coatings were discussed. Furthermore, the morphology of organic modified colloidal silica was investigated by performing TEM and SEM studies‥

Mechanical Behavior of Bioactive Glass-Polyvinyl Alcohol Hybrid Foams Obtained by the Sol-Gel Process

2005 ◽  
Vol 284-286 ◽  
pp. 757-760 ◽  
Author(s):  
Marivalda Pereira ◽  
Showan N. Nazhat ◽  
Julian R. Jones ◽  
Larry L. Hench
Keyword(s):  
Polyvinyl Alcohol ◽  
Bioactive Glass ◽  
Mechanical Behavior ◽  
Sol Gel ◽  
Precursor Solution ◽  
High Porosity ◽  
Soft Tissue Regeneration ◽  
Sol Gel Process ◽  
Potential Applications ◽  
Hybrid Foams

The possibility of enhancing mechanical properties by incorporation of polymeric components to sol-gel derived materials is extremely attractive to prepare macroporous scaffolds, leading to materials with potential applications in both hard and soft tissue regeneration. In this work bioactive glass-polyvinyl alcohol hybrids were developed and their mechanical behavior was evaluated. Hybrids were synthesized by adding polyvinyl alcohol to a sol-gel precursor solution, which was then foamed with the addition of a surfactant and vigorous agitation. The foams were cast, aged and dried at 40°C. A cleaning step to decrease the acidic character of the obtained hybrids was undertaken by immersion in a NH4OH solution. The mechanical behavior of the hybrids was evaluated in compression using both stress and strain control tests. Hybrid foams had a high porosity varying from 60-90% and the macropore diameter ranged from 10 to 600 µm. The modal macropore diameter varied with the inorganic phase composition and with the polymer content in the hybrid. The strain at fracture of the as prepared hybrid foams was substantially greater than pure gel-glass foams. The cleaned hybrids presented a slightly higher strength and lower deformation than the as prepared foams.

Preparation of Silica Aerogels Monoliths from Hydrophobic Silica Gels and Pluronic10R5 via Sol–Gel Process

2020 ◽  
Vol 12 (2) ◽  
pp. 206-211
Author(s):  
Supattra Eangpayung ◽  
Supan Yodyingyong ◽  
Darapond Triampo
Keyword(s):  
Mass Loss ◽  
Propylene Oxide ◽  
Silica Aerogel ◽  
Sol Gel ◽  
Silica Aerogels ◽  
Silica Gels ◽  
High Porosity ◽  
Hydrophobic Silica ◽  
Sol Gel Process ◽  
Poly Propylene

Silica aerogel, the most common type of aerogels, comprised of 95% air in its structure which made the aerogel has a high surface area, high porosity, low density, and low thermal conductivity. Because of its structure and high porosity, one of its major weakness compared to other materials is being very brittle. This study aims at strengthening the connection points between silica nanoparticles using Pluronic10R5 (poly(propylene oxide)8–poly(ethylene oxide)22–poly(propylene oxide)8) where the Pluronic10R5 was used to reduce phase separation during the silica condensation reaction in the sol–gel process. Silica aerogel monoliths were prepared via a sol–gel process from hydrophobic silica gels and Pluronic10R5 with an ambient pressure drying (APD) process. Results from the compression test showed that the Pluronic10R5/silica aerogels have improved mechanical property by ten times that of unmodified silica aerogels. A thermogravimetric analysis (TGA) showed a mass loss at 300–400 °C that is attributed to the surface methyl group, while a mass loss at 200 °C refers to the loss of Pluronic10R5 which confirms the incorporation of Pluronic10R5 into the monolith. Moreover, infrared (IR) images revealed that the top surface temperature of Pluronic10R5/silica aerogels monolith is about 80 °C differs from the bottom heat source temperature of 160 °C.

Preparation of porous alumina microspheres via an oil-in-water emulsion method accompanied by a sol–gel process

2016 ◽  
Vol 40 (1) ◽  
pp. 589-595 ◽  
Author(s):  
Hui Yang ◽  
Yuan Xie ◽  
Guisong Hao ◽  
Weiwei Cai ◽  
Xingzhong Guo
Keyword(s):  
Porous Alumina ◽  
Sol Gel ◽  
Three Dimensional ◽  
Water Emulsion ◽  
Emulsion Method ◽  
Oil In Water ◽  
Sol Gel Process ◽  
Template Free ◽  
Oil In Water Emulsion ◽  
Interconnected Structure

Porous alumina microspheres prepared via a facile template-free approach followed by heat-treatment, exhibiting a three-dimensional interconnected structure.

Facile synthesis of monolithic mayenite with well-defined macropores via an epoxide-mediated sol–gel process accompanied by phase separation

2014 ◽  
Vol 38 (12) ◽  
pp. 5832-5839 ◽  
Author(s):  
Xingzhong Guo ◽  
Xiaobo Cai ◽  
Jie Song ◽  
Yang Zhu ◽  
Kazuki Nakanishi ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Phase Separation ◽  
Sol Gel ◽  
High Porosity ◽  
Macroporous Structure ◽  
Facile Synthesis ◽  
Sol Gel Process

Monolithic mayenite has been successfully prepared via a sol–gel process followed by heat-treatment, exhibiting co-continuous macroporous structure and high porosity.

Synthesis of NaY Zeolite and their CO2 Adsorption Properties

2014 ◽  
Vol 1033-1034 ◽  
pp. 399-403
Author(s):  
Ren Juan Ma ◽  
Yong Quan Xu ◽  
Yu Min Liu ◽  
Rui Hong Zhao ◽  
Xiang Jing Zhang ◽  
...  
Keyword(s):  
Adsorption Capacity ◽  
Gas Flow ◽  
Separation Efficiency ◽  
Sol Gel ◽  
Fixed Bed ◽  
Nay Zeolite ◽  
Sol Gel Process ◽  
Curve Method ◽  
Ft Ir ◽  
Adsorption Desorption

NaY zeolite was prepared by a simple sol-gel process. The prepared NaY was characterized by XRD,FT-IR,N2adsorption/desorption isotherms, and scanning electron microscope (SEM). The CO2dynamic adsorption/desorption performance of NaY was tested under atmospheric pressure using adsorption curve method in the fixed bed. The results demonstrate that NaY offeres high separation efficiency for CO2against N2. To further identify the most adsorption conditions, different adsorption temperatures and gas flow rates were investigated respectively. It is shown that NaY zeolite has the largest adsorption capacity of 88 mg/g adsorbent at 60°C,50ml/min, and the sample maintains still strong adsorption capacity and stable structure during 6 consecutive test cycles, which exhibits its stable adsorption/desorption behavior.

scholarly journals Fabrication Of Carbon Aerogels From Coir For Oil Adsorption

2022 ◽  
Vol 964 (1) ◽  
pp. 012033
Author(s):  
Hieu M Nguyen ◽  
Khoi A Tran ◽  
Tram T N Nguyen ◽  
Nga N H Do ◽  
Kien A Le ◽  
...  
Keyword(s):  
Freeze Drying ◽  
Oil Spills ◽  
Sol Gel ◽  
Urea Solution ◽  
Carbon Aerogels ◽  
Low Density ◽  
High Porosity ◽  
Motor Oil ◽  
Sol Gel Process ◽  
Oil Adsorption

Abstract Coir, known as coconut fibers, are an abundant cellulosic source in Vietnam, which are mostly discarded when copra and coconut water are taken, causing environmental pollution and waste of potential biomass. In this research, carbon aerogels from chemically pretreated coir were successfully synthesized via simple sol-gel process with NaOH-urea solution, economical freeze-drying, and carbonization. The samples, including pretreated coir, coir aerogels, and carbon aerogels, are characterized using FTIR spectroscopy, SEM, XRD spectroscopy, and TGA. The carbon aerogels exhibit low density (0.034–0.047 g/cm3), high porosity (97.63–98.32 %), and comparable motor oil sorption capacity (22.71 g/g). The properties of carbon aerogels are compared with those of coir aerogels, indicating such better values than those of coir aerogels. Coir-derived carbon aerogels is a potential replacement for the hydrophobically-coated cellulose aerogels in term of treating oil spills.

Organic Biodegradable Aerogels Used in Controlled Drug Release

2011 ◽  
Vol 1306 ◽  
Author(s):  
Anja Veronovski ◽  
Zoran Novak ◽  
Knez Željko
Keyword(s):  
Drug Delivery ◽  
Drug Release ◽  
Nicotinic Acid ◽  
Sol Gel ◽  
Supercritical Drying ◽  
Diffusion Method ◽  
Cross Linking ◽  
High Porosity ◽  
Alginate Solution ◽  
Sol Gel Process

ABSTRACTThere are a lot of synthetic polymers which can be used for controlled drug delivery, however they are not easily accepted by the organism. Also incorporation of drugs into carriers runs under difficult conditions. Therefore scientists have been inclined to use natural-origin polymers, such as proteins and polysaccharides. Some of these promising natural polysaccharidic candidates are alginic acid sodium salt, guar gum and chitosan due to their outstanding merits. They are similar to extracellular matrix having high chemical versatility, good biological performance and cell or enzyme-controlled degradability. Many polysaccharidic hydrogels for drug delivery have already been prepared, but one of their weakness is their short life in dry air conditions; thus, special coating materials are being developed for enhancing their life time.Alginates were used in the present research for synthesis of organic biodegradable gels by sol-gel process, which were further easily converted to aerogels by supercritical drying. They are safe for use, nontoxic, and derived from renewable sources. Aerogels made of alginate are dry and stable materials, which makes them interesting as a substitute to hydrogels. Alginates undergo reversible gelation in aqueous solution through interaction with divalent cations such as Ca2+, which create ionic inter-chain bridges. Two fundamental methods of ionic cross-linking were used to prepare alginate hydrogels: the diffusion method, where spheres are created and the internal setting method resulting in monoliths. After producing the hydrogel, alcogels were formed by solvent exchange using 100% ethanol. Ethanol was later replaced by supercritical CO2 with supercritical drying (100 bar, 35°C). Aerogels made from natural polysaccharides combine both biocharacteristics and aerogel characteristics such as high porosity and specific surface area, which makes them really attractive in drug delivery applications. The aerogels obtained in present research were therefore studied as drug carriers. The effects of the alginate composition and synthesis method on model drug nicotinic acid release were investigated. The results indicated that by using the internal setting cross-linking method for obtaining aerogels nicotinic acid was released in a more controlled manner. That is why further investigation was done on alginate spherical beads for prolonging their drug release. A multi-step sol-gel process was applied to generate complex aerogels with multi-membranes. First ionically cross-linked spherical cores were obtained by dropwise addition of sodium alginate solution into a CaCl2 solution. These cores were further immersed into alginate solution, filtered through a sieve and dropped into a salt solution again. By repeating the above process, different multi-membrane hydrogels were produced and further converted to aerogels. By adding more membranes around core burst drug release was successfully inhibited.

scholarly journals Modification of Silica Coated on Iron Sand Magnetic Material with Chitosan for Adsorption of Au(III)

2017 ◽  
Vol 17 (2) ◽  
pp. 264 ◽  
Author(s):  
Muflikhah Muflikhah ◽  
Bambang Rusdiarso ◽  
Edy Giri Rachman Putra ◽  
Nuryono Nuryono
Keyword(s):  
Magnetic Material ◽  
Sol Gel ◽  
Order Kinetic ◽  
External Magnet ◽  
X Ray ◽  
Sol Gel Process ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Ft Ir ◽  
The Stability

Modification of silica coated on magnetic material iron sand with chitosan for adsorption of Au(III) has been carried out. Magnetic material (MM) from iron sand was separated using an external magnet, washed with water and HF solution 10%. MM–silica–chitosan material (MMSC) was synthesized via sol gel process and the product was characterized with Fourier Transform Infrared (FT-IR) spectrophotometer, X–ray diffractometer, scanning electron microscopy and energy dispersive X–ray, thermogravimetric analysis, and vibration sample magnetometer. Additionally, the effect of pH on the stability of MMSC has also been tested. The adsorption of Au(III) on MMSC was proceeded in a batch system with variation of pH, contact time, and concentration of absorbate. Adsorbent was separated using external magnet and concentration of Au(III) not adsorbed was analyzed using Atomic Absorption Spectrometer. Characterization result indicated that MMSC was successfully synthesized. Adsorption of Au(III) on MMSC followed pseudo second-order kinetic model with the value of adsorption rate constant (k) of 4.10 x 10-3 g mg-1 min-1 and adsorption isotherm fixed with Langmuir model with the adsorption capacity (qmax) of 149.25 mg g-1.

Sign in / Sign up

Export Citation Format

Share Document