scholarly journals Effects of Silica-Particle Coating on a Silica Support for the Fabrication of High-Performance Silicalite-1 Membranes by Gel-Free Steam-Assisted Conversion

Membranes ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 46 ◽  
Author(s):  
Kyohei Ueno ◽  
Hideyuki Negishi ◽  
Takuya Okuno ◽  
Hiromasa Tawarayama ◽  
Shinji Ishikawa ◽  
...  
Keyword(s):  
High Performance ◽  
Silica Particle ◽  
Particle Diameter ◽  
Silica Particles ◽  
Steam Treatment ◽  
Water Mixture ◽  
Silica Support ◽  
Chemical Waste ◽  
Silica Source ◽  
Particle Layer

Silicalite-1 membranes with high pervaporation performance were prepared successfully on a silica-particle-coated tubular silica support using a gel-free steam-assisted conversion (SAC) method. The effects of the silica-particle layer formed on the top surface of the silica support and the physical properties of the silica particles themselves on the membrane-formation process were investigated. The silica particles coated served as the additional silica source for growing the silicalite-1 seed crystal layer into the silicalite-1 membrane. As a result, it was possible to form a dense and continuous membrane even under gel-free conditions. Furthermore, it was found that the properties of the silica particles, such as their primary particle diameter, had a determining effect on their solubility during the steam treatment, that is, on the supply rate of the silica source. The silicalite-1 membrane obtained using the spherical-silica-particle-coated support had an approximately 9-μm-thick separation layer and showed very high pervaporation performance, exhibiting a separation factor of 105 and a flux of 3.72 kg m−2 h−1 for a 10 wt % ethanol/water mixture at 323 K. Thus, the gel-free SAC method can be used with a silica support coated with silica particles to readily prepare high-performance membranes without producing any chemical waste.

scholarly journals Chain length of bioinspired polyamines affects size and condensation of monodisperse silica particles

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Sai Prakash Maddala ◽  
Wei-Chih Liao ◽  
Rick R. M. Joosten ◽  
Mohammad Soleimani ◽  
Remco Tuinier ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Chain Length ◽  
Silica Particle ◽  
Particle Diameter ◽  
Reaction System ◽  
Particle Growth ◽  
Silica Particles ◽  
Growth Stages ◽  
Biphasic Reaction ◽  
The Impact

AbstractPolyamines play a major role in biosilicification reactions in diatoms and sponges. While the effects of polyamines on silicic acid oligomerization and precipitation are well known, the impact of polyamines chain length on silica particle growth is unclear. We studied the effects of polyamine chain length on silica particle growth and condensation in a known, simple, and salt-free biphasic reaction system; with tetraethyl orthosilicate as organic phase and polyamine dissolved in the aqueous phase. The particles at various growth stages were characterized by Cryo- Transmission Electron Microscopy, Scanning Electron Microscopy, Thermogravimetric Analysis, Zeta Potential, and solid-state NMR analysis. Polyamines were found co-localized within silica particles and the particle diameter increased with an increase in polyamine chain length, whereas silica condensation showed the opposite trend. Particle growth is proposed to progress via a coacervate intermediate while the final particles have a core shell structure with an amine-rich core and silica-rich shell. The results presented in this paper would of interest for researchers working in the field of bioinspired materials.

scholarly journals Effects of Cooking and Processing Methods on Phenolic Contents and Antioxidant and Anti-Proliferative Activities of Broccoli Florets

Antioxidants ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 641
Author(s):  
Hee Young Kim ◽  
Meran Keshawa Ediriweera ◽  
Kyung-Hwan Boo ◽  
Chang Sook Kim ◽  
Somi Kim Cho
Keyword(s):  
Antioxidant Activity ◽  
High Performance ◽  
Radical Scavenging ◽  
Steam Treatment ◽  
Drying Methods ◽  
Processing Methods ◽  
Phenolic Contents ◽  
Hot Air ◽  
Freeze Dried ◽  
Mcf 7

We investigated the effects of cooking (steaming and microwaving) and processing (freeze-drying and hot-air-drying) methods on the antioxidant activity of broccoli florets. 2,2-diphenyl-1-picrylhydrazyl (DPPH•), 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS•), and alkyl• free radical scavenging assays were employed to assess anti-oxidant potentials. The cytoprotective effect against oxidative damage induced by H2O2 was studied using hepatocellular carcinoma (HepG2) cells. Anti-proliferative effects were assessed in MCF-7 and MDA-MB-231 breast cancer cells. L-sulforaphane in broccoli extracts was quantified using high-performance liquid chromatography (HPLC). Steam and microwave treatments caused increases in total polyphenol content (TPC), whereas the total flavonoid content (TFC) decreased following steam treatment. A slight increase in TFC was observed in the microwaved samples. Extracts of all broccoli samples showed almost identical radical scavenging and cytoprotective effects. HPLC demonstrated that steamed (3 min)-freeze-dried (F-S3) and microwaved (2 min)-freeze-dried (F-M2) samples exhibited elevated levels of L-sulforaphane. In addition, the F-S3 and F-M2 extracts displayed strong anti-proliferative effects in MCF-7 cells, which correlated with L-sulforaphane content. As we observed no significant decrease in the antioxidant activity of broccoli florets, the cooking and processing methods and conditions studied here are recommended for broccoli.

Preparation of Silicalite-1 Membranes with Seeding Method and its Separation Performance for Low Ethanol/Water Mixture

2013 ◽  
Vol 807-809 ◽  
pp. 591-595
Author(s):  
Hong Liang Chen ◽  
Ji Song Yang ◽  
Yan Wang ◽  
Hui Ying Li ◽  
Xin Xin Li ◽  
...  
Keyword(s):  
Hydrothermal Synthesis ◽  
Separation Factor ◽  
High Performance ◽  
Separation Performance ◽  
Water Mixture ◽  
Synthesis Conditions ◽  
Seeding Method

High performance silicalite-1 membranes were successfully synthesized on silica tubes by seeding method after filling the tubes with water and glycerol mixtures. After seeding the silica tubes with 200 nm seeds, all the silicalite-1 membranes show acceptable separation performance towards ethanol/water mixture after 4-12 h hydrothermal synthesis, and the highest flux of membrane with 8 h hydrothermal synthesis reaches about 0.98 kg/m2.h and the separation factor reaches about 60 towards 3 wt.% ethanol/water mixture. This result shows that the as-synthesized silicalite-1 membrane can concentrate the ethanol from 3% to about 65%, and the ethanol can be obtained over 600 g/m2.h by using the silicalite-1 membrane, which shows that seeding method and suitable control of synthesis conditions is possible for preparing high-performance silicalite-1 membranes.

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