Characterization Of Silica Gel Research Articles

Synthesis and Characterization of Silica Gel from Palm Shell and Coir Ash

This study aims to determine the composition of the oxide, the characteristics of palm shell and coir, and silica gel synthesized. The oxide composition, crystallinity, palm shell and coir ash functional groups were analyzed using XRF, XRD, and FTIR. Analysis of the functional groups and crystallinity using FT-IR and XRD. The results showed the composition of SiO2 in palm shell and coir ash was 76%, and SiO2 in the form of quartz and cristobalite was more dominant than amorphous SiO2. The synthesis success was indicated by the appearance of peaks with low intensity, not sharp, and resembling bumps on the synthesized silica gel diffractogram, which is an amorphous SiO2 characteristic. This result is confirmed by FT-IR, where absorption at wave number 455 cm-1 is a Si-O-Si bending vibration, 783 cm-1 is a stretching vibration of Si-O symmetry of Si-O-Si, 3454.51 cm-1, and 3568 cm-1 with fairly high intensity are characteristic of the -OH group from Si-OH. The wide and sharp absorption at 1083.99 cm-1 is a stretching vibration of the Si-O symmetry of Si-O-Si, 1625.99 cm-1 is -OH vibration of water molecule, 798.53 cm-1 is Si-O stretching vibration of Si-O-Si and absorption of 462.92 cm-1 indicates bending vibration of Si-O-Si.

Synthesis and characterization of silica gel from Lapindo volcanic mud with ethanol as a cosolvent for desiccant applications.

Lapindo mud (LM) is a volcanic mud from a natural disaster that occurred 16 years ago in Sidoarjo District, East Java, Indonesia. The high amount of silica in the local materials of LM has been extracted for silica gel synthesis via hydrometallurgy methods, followed by sol-gel methods. The presence of ethanol in the synthesis process generated a unique textural property at different ratios between ethanol and sodium silicate (e/ss). Sol-gel mediated silica gel synthesis exhibited mesoporous properties with an amorphous structure, which is a characteristic of the silica gel. The silica gel exhibits silica nanoparticles over the average diameter of 2.08 nm with a spherical morphology and is connected to form an agglomeration structure. Increasing the e/ss ratio enhanced the amount of the hydroxyl group and the specific surface area ranged from 57 to 103 m2 g-1. The moisture adsorption performance of each silica gel showed that the silica gel with an e/ss ratio of 5 : 5 exhibited the highest adsorption capacity measured by conventional gravimetric methods and thermogravimetric analysis of 10.56% and 11.20% gwater gsilica -1, respectively. These results indicated that the silica gel with an e/ss ratio has a high number of hydroxyl groups and more surface-active sites, which is beneficial for the adsorption process. The adsorption capacity of the synthesized silica gel is also higher than that of the commercial silica gel, indicating an excellent performance for desiccant applications.

Pemurnian Bioetanol Menggunakan Adsorben Silika Gel dari Limbah Botol Kaca di Industri Kecap

Waste glass bottles is an inorganic waste that amounts to 0.7 million tons per year with the main content of silica, so it can be used as the main ingredient to produce silica gel. In the soy sauce industry, waste glass bottles came from depalletizer activities, the activity of moving glass bottles to the cleaning area. This research aims to utilize waste glass bottles as a raw material for producing silica gel adsorbents using the hydrothermal method and the sol-gel approach. Silica gel becomes an adsorbent in the purification of bioethanol from wastewater washing dissolving tanks using the adsorption method. Variations in the bioethanol production are yeast weight as 0, 2, 5, and 8 g as well as fermentation time for 4, 7, and 10 days.The bioethanol purification process used variations in adsorption time for 40, 60, and 80 minutes. Characterization of silica gel using BET and SEM-EDX test. The BET test results show that activated silica gel has a surface area of ​​231,851 m2/g. Analysis by SEM-EDX showed that the Si and O elements in activated silica gel were 40,94% and 51,92%. Based on the results of the GC-MS test, 60 minutes is the best adsorption time to increase the bioethanol content from 39,8±9,9% to 72,0±1,1%.

Synthesis and Characterization of Silica Gel from Corn Cob Ash and Its Adsorption Study Toward Cu(II) Metal Ion

Produksi jagung yang melimpah di Indonesia membuat munculnya permasalahan limbah berupa kulit dan tongkol jagung. Kulit jagung telah banyak dimanfaatkan untuk makanan ternak sedangkan tongkol jagung belum banyak dimanfaatkan. Tongkol jagung merupakan bahan yang mempunyai kandungan silika cukup tinggi yaitu sebesar 67,41%. Silika dalam limbah tongkol jagung ini dapat dimanfaatkan dalam pembuatan silika gel. Penelitian ini bertujuan untuk membuat dan mengkarakterisasi silika gel yang berasal dari abu tongkol jagung serta menguji daya adsorpsinya terhadap ion logam tembaga (II). Metode yang digunakan dalam pembuatan silika gel adalah metode sol-gel. Karakterisasi silika gel dilakukan dengan menggunakan FTIR (Fourier Transform Infra Red) dan XRD (X-ray Diffraction). Hasil penelitian menunjukkan bahwa kadar air dalam silika gel hasil sintesis dengan asam sulfat dan asam asetat berturut-turut adalah 13,314% dan 11,472%. Hasil karakterisasi gugus fungsi dengan FTIR dan kristalinitas menggunakan XRD bahwa silika gel hasil sintesis mempunyai kemiripan dengan Kiesel Gel 60G. Silika gel hasil sintesis dengan asam sulfat mempunyai daya adsorpsi dan efisiensi adsorpsi lebih tinggi dibandingkan dengan Kiesel Gel 60G serta silika gel hasil sintesis menggunakan asam asetat. Kata kunci: adsorpsi, abu tongkol jagung, silika gel

Synthesis and characterization of silica gel from Lapindo mud Sidoarjo

Silica gel was synthesized from Lapindo mud by the sol-gel process. XRF analysis confirmed that Lapindo mud contained silica (50%) which was major components, therefore Lapindo mud has great potential as a raw material for silica gel synthesis. Metal silicates commonly used as a precursor to prepare silica gel. A Lapindo mud was mixed with an alkaline solution, stirred and heated to prepare metal silicates. Hydrochloric acid was then slowly added to the metal silicates solution to obtain silica gel. The pH 4 selected as the optimum pH in the synthesis of silica gel. The purity of synthesized silica was determined by XRF and shown that silica purity by 100 mL sodium hydroxide 6 M (4 h, 80 °C) treatment was 63.25% with optimum yielded 32.3%. Whereas 12 M potassium hydroxide 200 mL (5 h, 90 °C) treatment could be produced better purity up to 77.71% with a yield of 39.72%.

Preparation and characterization of silicagel from silicate solution obtained by autoclave treatment of copper slag

The formation of silicagel from sodium silicate solution obtained by alkaline autoclave treatment of copper slag was investigated. The influence of the parameters of the gelation process (type of acid used, the pH of the medium, and drying conditions) on the structure and properties of the resulting silicagel, were studied. Silicagels obtained under different conditions were characterized by XRD, low-temperature nitrogen adsorption, FTIR, SEM, and TEM analyses. All silicagels are amorphous with a different degree of crosslinking. The physicochemical characterizations show that the type of acid, the mode of drying and pH influence the dispersity and the morphology of the silicagels prepared. Silicagels obtained at low-pH medium have a higher specific surface area and porosity than silicagels obtained at high-pH medium. Silicagels obtained at low-pH medium have no micropores and their porosity is only expressed by a narrow mesopore distribution. Freeze-drying improves the porosity of the silicagels obtained at high-pH medium. It is confirmed that the dilution of the sodium silicate solution affects the initial pH and the time of gelation.The moisture absorption capacity of the prepared silicagels increases in the following order: silicagel obtained at high-pH medium, dried in air < silicagel obtained at high-pH medium, freeze-dried < silicagel obtained at low-pH medium, dried in air.

Preparation and Characterization of Silica Gel from Bagasse Ash

Sugarcane bagasse is an agricultural waste that is potentially used as natural silica resources. Natural silica claimed to be safe in handing, cheap and can be generate from cheap resource. In the objectives of this study were to prepared silica from Sugarcane bagasse. The preparation of Sugarcane bagasse ash by burning at 700 °C for 4 and 6 h, respectively in atmosphere. The result of X-ray florescent: XRF, silica content which was obtained after heat treatment at 700 °C for 6 h was 80.814 wt%. Bagasse ash was purified by alkaline extraction method with 1.5, 2 and 2.5 N sodium hydroxide (NaOH), respectively. And refluxed by using concentrated 2 N sulfuric acid. From X-ray diffraction pattern showed that the obtained products were amorphous silica, 2.5 N sodium hydroxide. The morphology was observed by SEM, sphere and average particles dimension of synthesis silica with 1.5, 2 and 2.5 N NaOH are 120, 100 and 80 nm respectively. The SEM micrographs showed that the Concentration of NaOH was increased, the particles dimension decreased

Characterization of Silica Gel Impregnated with Tetradecylamine by X-Ray Diffractometry and Brunauer-Emmet-Teller Studies

Commercially available porous silica gel (SG) is chemically modified for carbon dioxide capture. Calcinated silica gel functionalized with amine (tetradecylamine, TDA) using wet impregnation has been employed as a porous media. The prepared adsorbents is characterized by x-ray diffractometry (XRD) and N2 physisorption techniques (Brunauer-Emmet-Teller analysis, BET). Appearance of 3 new crystalline peaks on 65TDA/SG diffractogram evidenced the presence of TDA molecules on the SG. Significant changes in physical properties of the adsorbents further ascertained the dispersion of TDA on the internal channels and external surface of the SG.

Preparation and Characterization of Silica Gel from Wheat Straw

Preparation and Characterization of Silica Gel from Wheat Straw

Synthesis and Characterization of Novel Sulfur-Functionalized Silica Gels as Mercury Adsorbents

This paper describes the synthesis, functionalization, and characterization of silica gels as mercury adsorbents. The synthesis was carried out according to the modified Stober method using tetraethyl orthosilicate [TEOS], 3-mercaptopropyl trimethoxysilane [MPTMS] and bis(triethoxysilylpropyl) tetrasulfide [BTEPST] as precursors. The functionalization was carried out via co-condensation and impregnation methods using MPTMS, BTESPT, elemental sulfur [ES], and carbon disulfide [CS2] as sulfur ligands. The choice of the sulfur ligands as precursors and functionalization agents was due to the existence of sulfur active groups in their molecular structures which were expected to have high affinity toward Hg(II) ions. The synthesized adsorbents were characterized by using scanning electron microscope, fourier transform infrared spectrophotometer, nitrogen adsorption/desorption, and energy dispersive X-ray diffractometer. The batch Hg(II) adsorption experiments were employed to evaluate the Hg(II) adsorption performances of the synthesized adsorbents under different pH values. The results revealed that the highest Hg(II) adsorption capacity was obtained for the SG-MPTMS(10) which was 47.83 mg/g at pH 8.5. In general, the existence of sulfur functional groups, especially MPTMS in the silica matrices, gave a significant enhancement of Hg(II) adsorption capacity and the sulfur functionalization via co-condensation method, which is potential as a superior approach in the mercury adsorbent synthesis.

Synthesis and characterization of silica gel from siliceous sands of southern Tunisia

The present work aimed to achieve valorization of Albian sands for the preparation of sodium silicates that are commonly used as a precursor to prepare silica gel. A siliceous sand sample was mixed with sodium carbonate and heated at a high temperature (1060°C) to prepare sodium silicates. The sodium silicates were dissolved in distilled water to obtain high quality sodium silicate solution. Hydrochloric acid was then slowly added to the hydrated sodium silicates to obtain silica gel. The collected raw siliceous sands, as well as the prepared silica gels, were characterized by different techniques, such as X-ray fluorescence (XRF), X-ray diffraction (XRD), scanning electron microscopy (SEM) and thermal analysis (DSC). XRF confirmed that the detrital sand deposits of southern Tunisia contain high amounts of silica, with content ranging from 88.8% to 97.5%. The internal porosity varied between 17% and 22%, and the specific surface area was less than 5m2/g. After the treatment described above, it was observed that the porosity of the obtained silica gel reached 57% and the specific surface area exceeded 340m2/g. Nitrogen adsorption isotherms showed that the prepared silica gels are microporous and mesoporous materials with high adsorption capacities. These results suggest that the obtained silica gels are promising materials for numerous environmental applications.

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

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 Silica Gels by 29Si MAS NMR and IR Spectroscopic Measurements

AbstractThe solubility of commercial and synthesized silica gels in a solution of Tetra‐Ethyl‐Ammonium‐Hydroxide (TEAOH) was investigated at room temperature. The state of parent silica frameworks was characterized by BET and SEM. The structural defects were identified both by the Qn group analysis in 29Si MAS NMR and IR spectroscopic investigation. It was found that the dissolution rate of the samples shows a tendency for growing up with an increasing BET surface. The increase of the internal surface was accompanied by formation of Si(OSi)3(OH) (Q3) and Si(OSi)2(OH)2 (Q2) structural units. The higher the number of Q3 and Q2 groups observed, the faster the samples were dissolved in TEAOH solution due to the attack of the hydroxide ions on the terminal OH groups of the framework. The asymmetrical TOT valence vibration of the IR spectra was systematically shifted to lower values with increase in the number of Q3 and Q2 structure groups.

Synthesis and Characterization of Silica Gels Functionalized with Monochlorotriazinyl β-Cyclodextrin and their Sorption Capacities towards Organic Compounds

Different supports, containing a new derivative ofβ-cyclodextrin – monochlorotriazinylβ-cyclodextrin (β-CDMCT) – used forthe reduction of pollutants in waste water, have beenprepared. They are based on silica gel, initially eithercoated with polyethyleneimine (PEI) or grafted with3-aminopropyltrimethoxysilane, functionalized in asecond step with β-CDMCT. In order to obtainsorbents with high β-cyclodextrin content andmaximum accessibility of the β-CD cavity, thefuntionalization was studied while varying experimentalconditions. Thermogravimetry, Raman spectroscopy,specific surface area and pore size distribution were usedfor the characterization of supports. Sorption experimentsshow that these sorbents have sorption capacities towardssome organic pollutants. The mechanism of sorption is bothphysical adsorption in the polymer network (for supportsobtained by coating) and/or the formation of an inclusioncomplex between β-CDMCT and guest molecules.

Hydrothermal and microwave-hydrothermal preparation of silica gels

We report here the rapid preparation and characterization of silica gels under conventional-hydrothermal (CH) as well as microwave-hydrothermal (MH) conditions from tetraethoxysilane and water in a molar ratio of 1:4 but without adding any alcohol as a co-solvent. Silica gels were prepared at 138 °C in 2 h by both CH and MH processing while heating in an oven at 60 °C required 48 h for complete gelation. Gelation was not complete in a water bath at 60 °C even after 48 h. The rapid preparation of silica gels under CH and MH conditions is expected to save time, and maybe energy.

Synthesis and Characterization of Silica Gels Obtained in Lamellar Media

Synthesis and Characterization of Silica Gels Obtained in Lamellar Media

Effect of preparation pH on pore structure of silica gels

Surface characterization of silica gels prepared at different gelation pH from water glass and sulphuric acid were made by argon adsorption at 77 K using continuous volumetric method. While microporous silica gels prepared in the pH range of 1–3 had BET surface areas of 504–571 m2 g−1, total pore volumes of 0.26–0.31 cm3 g−1 and micropore volumes of 0.16–0.23 cm3 g−1, mesoporous silica gels prepared in the pH range of 3.36–0.65 had BET surface areas of 374–530 m2 g−1 and pore volumes of 0.61–0.79 cm3 g−1.

Modification of silica gel with diethylamino group by novel reaction and its characterization

1,3,5,7-Tetramethylcyclotetrasiloxane (H4) was deposited on silica gel at 80°C by utilizing a chemical vapor deposition (CVD) method, where it was catalytically polymerized to form a surface coating of polymethylsiloxane (PMS). Treated silica gel (PMS-Si) increased in weight up to a plateau level, and there was no further increase with increasing reaction time. The film of PMS was partially cross linked; typical values of crosslinking ratio and film thickness were 2% and 0.6 nm, respectively. An anionic ion exchanger containing diethylamino groups was synthesized from PMS-Si by hydrosilylation of allyl glycidyl ether followed by treatment with diethylamine. Its structure was confirmed by13C and29Si CP/MAS NMR spectroscopy and FT-IR spectrophotometry. Characterization of silica gel (DEA-Si) modified with diethylamino group was evaluated by a packing of the column for liquid chromatography. As a mixture of five nucleotides was completely separated, it was recognized that DEA-Si was operated by ion exchange action. Because the surface of the silica gel was covered with hydrophobic PMS, the peak heights and retention times did not change after washing of the column with alkaline solution.

Characterization of silica gels by infrared reflection spectroscopy

The FTIR specular reflection spectra of porous silica gels, either dried at room temperature or subjected to partial densification at 400°C, are significantly different from the spectrum of bulk vitreous silica. Namely, the high frequency SiOSi stretching vibrational peak near 1100 cm −1 exhibits shifts in the gels of up to 40 cm −1 towards lower frequencies, whereas the relative intensity of the companion high frequency shoulder simultaneously increases. The origin and possible structural meaning of the observed changes were investigated by Kramers-Kronig analysis of the experimental near-normal infrared reflectivity spectra of a series of silica xerogels, porous Vycor and bulk vitreous silica. Major differences were found for the energy loss function Im(−1/ϵ ∗), the peaks of which have been associated with the LO components of the dominant vibrational modes, and the largest red shifts corresponded to the highest frequency mode. Simple calculations show that the observed behavior of the infrared spectra could in part be due to a certain degree of strain in the SiOSi bridging bonds at the surface of the gel pores.

Charakterisierung von kieselgelen nach porensystem und aktivität

Characterization of silica gels by their pore systems and activitiesThe activity of a silica gel is determined by its pore system, the surface quality of the frame substance, and the saturation grade of the silanol groups with water. The specific chromatographic properties of standardized silica gels with pore diameters of 40, 60 and 100 Å and with definite pore volumes, specific surface areas, and water adsorption isotherms are discussed.