scholarly journals EFFECT OF ACID CONCENTRATION ON CHARACTERS OF SILICA GEL SYNTHESIZED FROM SODIUM SILICATE

2010 ◽  
Vol 5 (1) ◽  
pp. 23-30 ◽  
Author(s):  
Nuryono Nuryono ◽  
Narsito Narsito
Keyword(s):  
Citric Acid ◽  
Water Content ◽  
Adsorption Capacity ◽  
Sodium Silicate ◽  
Silica Gel ◽  
Acid Concentration ◽  
Water Adsorption ◽  
Sol Gel ◽  
Silica Gels

In this research, synthesis and characterization of silica gel from sodium silicate through sol-gel process using H2SO4, HCl, and citric acid have been investigated. Synthesis was carried out by mixing and stirring  20 mL of H2SO4, HCl or citric acid  at certain concentration with 50 mL of sodium silicate solution (Na2O 0.17 M and SiO2 0.61 M) for one hour and let to form gel.  The gel was washed with distillated water, and dried in an oven at 100 oC. Characterization of silica gel was carried out by determination of acidity, water adsorption capacity, and water content. Identification of functional group and structure were identified using x-ray diffractometer (XRD) and infrared (IR) spectrophotometer, respectively.  Results showed that at a range of investigated concentration (0.6 - 3.0 M) the increase of concentration, formation of gel with H2SO4 tended to be faster, but with HCl and citric acid to be slower. The increase of acid concentration caused water content, water adsorption capacity, and acidity of the silica gel resulted with HCl and citric acid tended to be increased, increased, and increased, but with H2SO4 to be decreased, increased, and decreased, respectively. Based on the IR spectra and XRD data, it could concluded that the synthetic silica gels contained silanol (Si-OH) and siloxane (Si-O-Si) and were amorphous, showing similar pattern to kieselgel G 60 produced by Merck.   Keywords: silica gel, adsorption capacity, sodium silicate, acidity

Characterization of Selenium Doped Silica Gels Synthesized by Sol-Gel Method

2014 ◽  
Vol 805 ◽  
pp. 564-569
Author(s):  
Renata Andrade Kobayashi ◽  
Samuel Marcio Toffoli
Keyword(s):  
Sol Gel ◽  
Silica Gels ◽  
Glassy Matrix ◽  
Industrial Glass ◽  
Rare Element ◽  
Gel Method ◽  
Sol Gel Method ◽  
Red Color ◽  
Synthesized Materials

Selenium is a rare element in nature. It is used in the food, pharmaceutical, and glass industries. In commercial glasses, selenium is the element responsible for most of the pink or light red color, but its effect is primarily dependent on the oxidation state of the element in the glassy matrix. Besides, selenium is highly volatile, and as high as 80 wt% may be lost in the furnace during the industrial glass elaboration. The sol–gel method yields synthesized materials of high purity and homogeneity, and uses low processing temperatures. Samples of silica gels were obtained by sol-gel method, incorporating precursors of selenium, with the main objective of reducing selenium losses during its heating. The results of optical absorption, XRD and thermal analysis (TGA, DSC) of the gels are presented and discussed.

Synthesis and Characterization of Immobilized Nanometer Calcium Titanate and the Application in Speciation Analysis for Chromium

2010 ◽  
Vol 129-131 ◽  
pp. 724-727
Author(s):  
Dong Zhang
Keyword(s):  
Silica Gel ◽  
Sol Gel ◽  
Speciation Analysis ◽  
Environmental Water ◽  
Complete Separation ◽  
Calcium Titanate ◽  
X Ray Diffraction ◽  
Ph Values ◽  
Adsorption Capacities

Nanometer calcium titanate immobilized on silica gel G (SGCTO) was prepared by the sol–gel method and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infrared spectrophotometry (FTIR). Its application in speciation of Cr(III) and Cr(VI) from water was studied. Adsorption and elution were investigated under different conditions. The results showed that the nanometer calcium titanate was immobilized on the silica gel G firmly, becoming a new adsorbent. At normal temperature, two forms of chromium show different adsorption capacities at different pH values, that is, Cr (III) selectively retained at pH 8–14, but Cr(Ⅵ) can’t be adsorbed. Whereas Cr (VI) retained at pH 1, but Cr(Ⅲ) can’t be adsorbed. Hence complete separation of the two forms of chromium is possible. Retained Cr(III) and Cr(VI) were eluted with 1 mol•L−1 HCl and 2 mol•L−1NaOH, respectively. The Cr(III) and Cr(VI) concentration was measured by atomic absorption spectroscopy. The method was successfully applied for the speciation of chromium in environmental water samples.

scholarly journals Synthesis and characterization of poly-aluminum silicate sulphate (PASS) for ultra-low density fiberboard (ULDF)

RSC Advances ◽  
2015 ◽  
Vol 5 (113) ◽  
pp. 93187-93193 ◽  
Author(s):  
Tingjie Chen ◽  
Min Niu ◽  
Xiaodong Wang ◽  
Wei Wei ◽  
Jinghong Liu ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Sodium Silicate ◽  
Sol Gel ◽  
Synthesis And Characterization ◽  
Aluminum Silicate ◽  
Low Density ◽  
Gel Method ◽  
Sol Gel Method ◽  
Mixed Aqueous Solution

Poly-aluminum silicate sulphate (PASS) was synthesized in a mixed aqueous solution of sodium silicate and aluminum silicate via a sol–gel method for use in ultra-low density fiberboard (ULDF).

scholarly journals Synthesis and Characterization of Trimethylchlorosilane-Modified Silica Xerogel

2020 ◽  
Vol 23 (7) ◽  
pp. 249-254
Author(s):  
Sellen Tanheitafino ◽  
Anis Shofiyani ◽  
Risya Sasri ◽  
Rudiyansyah Rudiyansyah
Keyword(s):  
Contact Angle ◽  
Citric Acid ◽  
Sodium Silicate ◽  
Sol Gel ◽  
Volume Ratio ◽  
Silica Xerogel ◽  
Silica Xerogels ◽  
Modified Silica ◽  
Average Pore ◽  
Pore Size Distributions

Modification of silica xerogel with TMCS (trimethylchlorosilane) reagent has been carried out to improve the hydrophobicity of silica xerogel. Silica xerogel was synthesized based on the sol-gel method using sodium silicate as a precursor, and citric acid as a catalyst, with a mole ratio of sodium silicate and citric acid, was 0.172: 0.004. The sol-gel process was carried out through several stages, i.e., hydrolysis and condensation of sodium silicate to form sol, gelation (sol transition to gel), aging, and drying. Surface modification was performed by studying the effect of TMCS: methanol: petroleum benzine volume ratio of 0.5:1:1, 1:1:1, 1.5:1:1, 2:1:1, and 2.5:1:1 on the characteristics of silica xerogel synthesized. FTIR, SEM, and GSA characterized the synthesized results. The results of FTIR characterization on silica xerogel with volume ratios of 2:1:1 and 2.5:1:1 indicate the presence of the Si‑C group absorption at a wavenumber of 848.68 cm-1 which shows that the formation of silyl groups on the modified silica xerogel surfaces occurs at a TMCS: methanol: petroleum benzine ratio of 2:1:1 and 2.5:1:1. SEM results indicate that the silica xerogels produced are porous. Meanwhile, the GSA analysis results show that the pore size distributions are in the mesoporous region with an average pore radius of 8-13 nm. The greater the volume of TMCS used, the higher the surface area, and the resulting xerogel’s hydrophobicity. Based on the contact angle and seeped time test, the highest hydrophobicity is produced by the material synthesized at a TMCS: methanol: PB volume ratio of 2.5:1:1 with a contact angle of 116.346°.

Characterization of LaCoO3 powders obtained by water-based sol–gel method with citric acid

2007 ◽  
Vol 27 (13-15) ◽  
pp. 4407-4411 ◽  
Author(s):  
Luminita Predoana ◽  
Barbara Malic ◽  
Marija Kosec ◽  
Mariana Carata ◽  
Monica Caldararu ◽  
...  
Keyword(s):  
Citric Acid ◽  
Sol Gel ◽  
Gel Method ◽  
Sol Gel Method ◽  
Water Based
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