Effect of pH and chitosan concentration on precipitation and morphology of hierarchical porous silica

2011 ◽  
Vol 357 (19-20) ◽  
pp. 3513-3519 ◽  
Author(s):  
Thongthai Witoon ◽  
Soponwit Tepsarn ◽  
Puscharapon Kittipokin ◽  
Ben Embley ◽  
Metta Chareonpanich
Keyword(s):  
Porous Silica ◽  
Effect Of Ph ◽  
Chitosan Concentration ◽  
Hierarchical Porous

Eco-fabrication of hierarchical porous silica monoliths by ice-templating of rice husk ash

2017 ◽  
Vol 19 (1) ◽  
pp. 188-195 ◽  
Author(s):  
Amin Bahrami ◽  
Ulla Simon ◽  
Niloofar Soltani ◽  
Sara Zavareh ◽  
Johannes Schmidt ◽  
...  
Keyword(s):  
Rice Husk ◽  
Rice Husk Ash ◽  
Porous Silica ◽  
Synthesis Process ◽  
Sustainable Chemistry ◽  
Silica Monoliths ◽  
Hierarchical Porous ◽  
Ice Templating

In this study, within a sustainable chemistry approach, a clean and eco-friendly synthesis process of silica monoliths compatible with environmental limitations is developed.

scholarly journals Enhanced Phenol Tert-Butylation Reaction Activity over Hierarchical Porous Silica-Alumina Materials

Catalysts ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1098
Author(s):  
Ling Xu ◽  
Fan Wang ◽  
Zhi Xiu ◽  
Limei Duan ◽  
Zongrui Liu ◽  
...  
Keyword(s):  
Physical Adsorption ◽  
Porous Silica ◽  
Mesoporous Structure ◽  
Catalytic Performance ◽  
Crystallization Time ◽  
Hydrothermal Conditions ◽  
Transmission Electron ◽  
Hierarchical Porous ◽  
Silica Alumina ◽  
Ft Ir

Hierarchical aluminum-silicon materials have been successfully prepared by mixing pre-crystallization of silica-alumina sol and citric acid under hydrothermal conditions. The influence of pre-crystallization time on the micro-mesoporous structure is studied using Fourier transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD), N2 physical adsorption, and high-resolution transmission electron microscopy (HRTEM). The catalytic performance of hierarchical silica-alumina material is evaluated by alkylation of phenol with tert-butanol. The results show that the silica-alumina materials with a pre-crystallization time of 16 h show micro-mesoporous structure and excellent catalytic activity.

Mechanically Strong and Hierarchical Porous Silica Ceramics via Gelcasting-Lyophilization

2016 ◽  
Vol 697 ◽  
pp. 414-418
Author(s):  
Wei Wan ◽  
Jian Yang ◽  
Yong Bao Feng ◽  
Tai Qiu
Keyword(s):  
Raw Materials ◽  
Aqueous Suspension ◽  
Three Dimensional ◽  
Porous Silica ◽  
Hierarchical Porous ◽  
Exhaust Fumes ◽  
Materials Used ◽  
Gelcasting Process ◽  
Hierarchical Pore ◽  
Highly Porous

Highly porous silica ceramics were prepared by in-situ gelation of an aqueous suspension with well dispersed silica particles and N’N-dimethylacrylamide (DMAA) monomer, followed by lyophilization and pressureless sintering. The gelcasting process was imparted by polymerization of DMAA. The silica raw materials used in this experiment are the dusts collected from the exhaust fumes of silicon industry. The as-obtained porous silica ceramics had three-dimensional and hierarchical pore structure and the porosity ranged from 75 to 88 % as the sintering temperature varied from 850 to 1050 °C. In addition, the porous silica ceramics appeared to have strong mechanical strength. Compressive strength of the porous silica ceramics was as high as 3.2 MPa even when the porosity was nearly 80%. The gelcasting-lyophilization method was proved to be a novel and promising route for the preparation of highly porous and mechanically strong materials.

Synergic effects of a protic ionic liquid on P123 mixed micelles for inducing hierarchical porous materials

RSC Advances ◽  
2015 ◽  
Vol 5 (66) ◽  
pp. 53267-53274 ◽  
Author(s):  
Shuo Zhao ◽  
Xiaoli Sheng ◽  
Yuming Zhou ◽  
Man He ◽  
Xiaoqin Fu ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Porous Materials ◽  
Formation Mechanism ◽  
Mixed Micelles ◽  
Porous Silica ◽  
Protic Ionic Liquid ◽  
Hierarchical Porous

Postulated formation mechanism of hierarchical porous silica.

Morphology and adsorption capacity of sodium silicate-based hierarchical porous silica templated on natural rubber: Influence of washing–drying methods

2014 ◽  
Vol 130 ◽  
pp. 206-209 ◽  
Author(s):  
C. Phatharachindanuwong ◽  
N. Hansupalak ◽  
M. Chareonpanich ◽  
Y. Chisti ◽  
J. Limtrakul ◽  
...  
Keyword(s):  
Natural Rubber ◽  
Adsorption Capacity ◽  
Sodium Silicate ◽  
Porous Silica ◽  
Drying Methods ◽  
Hierarchical Porous

Production and characterization of hierarchical porous silica made using natural rubber as template: Effects of the template removal methods, the pH of production, and the natural rubber sources

2016 ◽  
Vol 113 ◽  
pp. 273-283 ◽  
Author(s):  
Chayani Phattharachindanuwong ◽  
Nanthiya Hansupalak ◽  
Kanokwan Jantawatchai ◽  
Chompunuch Warakulwit ◽  
Johann Plank ◽  
...  
Keyword(s):  
Natural Rubber ◽  
Porous Silica ◽  
Template Removal ◽  
Hierarchical Porous

scholarly journals Highly Active Hydrogenation Catalysts Based on Pd Nanoparticles Dispersed along Hierarchical Porous Silica Covered with Polydopamine as Interfacial Glue

Catalysts ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 449
Author(s):  
Miguel Ródenas ◽  
Jamal El Haskouri ◽  
José Vicente Ros-Lis ◽  
M. Dolores Marcos ◽  
Pedro Amorós ◽  
...  
Keyword(s):  
Porous Silica ◽  
Catalytic Efficiency ◽  
Pd Nanoparticles ◽  
Hydrogenation Catalysts ◽  
Highly Active ◽  
Hierarchical Porous ◽  
Similar Materials ◽  
Comprehensive Comparison ◽  
Palladium Content

New catalysts based on Pd(0) nanoparticles (Pd NPs) on a bimodal porous silica of the UVM-7/polydopamine (PDA) support have been synthesized following two preparative strategies based on the sequential or joint incorporation of two components of the composite (Pd and PDA). We analyzed the role played by the PDA as ‘interfacial glue’ between the silica scaffold and the Pd NPs. The catalysts were tested for the hydrogenation of 4-nitrophenol using (NEt4)BH4 as the hydrogenating agent. In addition to the palladium content, the characterization of the catalysts at the micro and nanoscale has highlighted the importance of different parameters, such as the size and dispersion of the Pd NPs, as well as their accessibility to the substrate (greater or lesser depending on their entrapment level in the PDA) on the catalytic efficiency. Staged sequential synthesis has led to better catalytic results. The most active Pd(0) centers seem to be Pd NPs of less than 1 nm on the PDA surface. The efficiency of the catalysts obtained is superior to that of similar materials without PDA. A comprehensive comparison has been made with other catalysts based on Pd NPs in a wide variety of supports. The TOF values achieved are among the best described in the literature.

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