Addition Of TEOS Research Articles

The Effect of Tetraethil OrthoCilicate (TEOS) on Fe3O4 Nanoparticles Addition in Electrical

<p class="Abstract">Magnetite Nanoparticles of pure (Fe<sub>3</sub>O<sub>4</sub>) and Fe<sub>3</sub>O<sub>4</sub> with TEOS addition have been successfully synthesized from natural iron sand using the coprecipitation method. The purpose of this study is to provide information on the effect of TEOS to Fe<sub>3</sub>O<sub>4</sub> on the electrical properties. The effect of TEOS addition to Fe<sub>3</sub>O<sub>4</sub> indicates that the increase in true density results is 4.95 gr/cm<sup>3</sup>. The stability of nanolubricant on Fe<sub>3</sub>O<sub>4</sub> nanoparticles with the addition of TEOS 1.2 ml was dispersed homogeneously. The value of thermal conductivity also increases due to TEOS addition on Fe<sub>3</sub>O<sub>4</sub> nanoparticles in a volume fraction of 0.8% of 1,631 W/m.K and the heat of the type produced was 718.44 J/kg.K. The effect of TEOS addition on Fe<sub>3</sub>O<sub>4 </sub>nanoparticles produces good electrical properties of stability in the nano-lubricant.</p>

Polyethylene Glycol as Surface Modification of Magnetite Nanoparticle Coated Silica a Potentially Hyperthermia Therapy Material

Local hyperthermia therapy is one of the cancer treatments by implementing heat from a temperature of 41-45°C on cancer cells. This method is believed to reduce the risk of normal cells around the cancer cells from dying. The form of hyperthermia therapy itself is in ferrofluid. During its development, superparamagnetic nanoparticles of iron oxide have attracted various studies because of their good magnetic properties and good biocompatibility. However, the poor particle interactions and their tendency to aggregation make coatings on superparamagnetic necessary. Therefore, silica coating on the superparamagnetic surface is carried out to reduce the risk of aggregation and increase the biocompatibility of the material. Polyethylene glycol functionalization was also applied to improve the biocompatibility of the material, as well as being a carrier for ferrofluid. The test was carried out using the magnetite co-precipitation synthesis method and the formation of a sol-gel silica coating. Variations applied in this experiment are the effects of TEOS concentration as a source of silica and the ratio of particles to PEG. The addition of silica was proven to increase the value of the magnetic moment to 51.55 emu/g. The addition of TEOS as a source of silica in iron (III) nanoparticles has an effect on increasing the magnetic attraction, decreasing the surface tension value, reducing particle size, and decreasing the SAR value. Functionalization of polyethylene glycol has the effect of reducing the magnetic moment, increasing and decreasing hydrophobicity, increasing the surface tension value, and reducing the particle size of iron (III) oxide nanoparticles. This shows that magnetic nanoparticles coated with silica with polyethylene glycol functionalization are proven to generate heat when given AC current with the SAR value and the highest temperature is found in iron (III) oxide which gets 3ml silica coating with a PEG ratio of 2:5 at a temperature of 32.2°C. and SAR value of 87.63 W/mg

Robust underwater superoleophobic coatings based on zwitterionic P(CBMAE‐co‐TMSPMA)/SiO2 with anti‐adhesive behavior

AbstractThis study focuses on the surface modification of substrates using a poly(N,N‐dimethyl‐N‐(ethoxycarbonylmethyl)‐N‐[2′‐(methacryloyloxy) ethyl]‐ammonium chloride‐co‐3‐(trimethoxysilyl)propylmethacrylate) P(CBMAE‐co‐TMSPMA) and ethyl orthosilicate (TEOS). By covalently bonding the Si‐OH pendant of the copolymer with hydroxyl residues on the material's surface, a stable polymer coating is formed. The properties of P(CBMAE‐co‐TMSPMA) coatings were evaluated using Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), scanning electron microscope (SEM), and contact angle (CA) meter. The addition of TEOS allows for the regulation of surface roughness. With the increase of TEOS content, the contact angle of underwater oil first increased and then decreased. The water contact angles were 8°, the underwater superoleophobic contact angle reached 168°, and the number of adherent platelets and Escherichia coli were significantly reduced to 7.5% and 5% on the surface of the coating, respectively. After undergoing simultaneous hydrolysis, the superoleophobic contact angle of P(CBMAE‐co‐TMSPMA)/SiO2 coating further increased to 174°. These interesting and robust properties make them promising candidates for biomedical applications.Highlights The underwater superoleophobic coating (contact angles of 174°). The P(CBMAE‐co‐TMSPMA)/SiO2 coating with excellent resistance to oil adhesion. Solve the hydroxyl residue problem. The coating resistance to E. coli and platelet adhesion.

The use of new class α-amino nitrile modified magnetic adsorbents for removal of Cd(II) from aqueous medium: Sorbent modification vs. α-amino nitrile addition to the adsorption medium

In the present work, some novel α-amino nitriles were prepared: amino-2- (anthracen-9-yl) acetonitrile (AAN), and 2-(naphthalen-1-yl) -2- ((triethoxysilyl) propyl) amino) acetonitrile (Si-AN). With the aid of other organic compounds (3-aminopropyl triethoxysilane “APTES” and tetraethyl orthosilicate “TEOS”), the following carbon nanotubes “CNT” and magnetite “Mag” based adsorbents were prepared: CNT-AAN, Mag-SiO2, Mag-SiO2-APTES, Mag-SiO2-Si-AN. The FT-IR, 1H and 13C NMR spectroscopy proved the formation of (C N) and (NH-) bonds which indicated successful amino nitrile modification of the adsorbents. The ability of the above-mentioned adsorbents to remove cadmium “Cd(II)” from water was studied at various pH values. CNT modification with AAN reduced Cd(II) uptake, while all Mag modifications increased Cd uptake. The addition of AAN to the extraction medium with CNT sorbent reduced Cd(II) uptake. The addition of TEOS and Si-AN to the extraction medium for Cd(II) removal using Mag was studied where a positive impact was observed. Based on the above experiments, it was decided to use Mag as adsorbent with the addition of Si-AN to the extraction medium. Method optimization recommended pH 8 and Cd:Si-AN molar ratio of 1:1. The maximum adsorption capacity towards Cd(II) achieved in this study was 65 mg g−1. The method selectivity, re-usability and applicability on well water and tap water samples gave appropriate results. The adsorption of Cd(II) on Mag in the presence of Si-AN was fast, endothermic, spontaneous, favored and physi-sorption was predominant.

A computational and experimental investigation of TEOS-treated graphene oxide-PVA interaction: Molecular dynamics simulation and COSMO-RS insights

This research investigates the effect of tetraethyl orthosilicate TEOS on the interaction mechanism in the hybrid polyvinyl alcohol (PVA)/graphene oxide (GO) material. PVA, PVA/Go, and PVA/GO-SiO2 are produced by the solution casting method. The TEOS treated GO is confirmed by FTIR and also suggests that PVA is chemically bonded to GO-SiO2. XRD results reveal that the crystallinity of PVA is significantly reduced with the addition of TEOS as it becomes completely amorphous and shows that the GO has a full exfoliation in the matrix. However, thermogravimetric analysis indicates that the incorporation of GO improves the thermal stability of PVA by reducing its mass-loss rate upon heating. Theoretical molecular dynamic simulations indicate that the addition of SiO2 could significantly improve the binding interaction energies from 14387 kcal/mol to 15039 kcal/mol for 6PVA/3GO and 6PVA/3GO-3SiO2 systems, respectively. These simulations also highlight the occurrence of a hydrogen bonding between PVA and GO oxygen groups and PVA and Si-OH groups. The Conductor-like Screening Model for Real Solvents (COSMO-RS) study shows the intermediary role played by SiO2, which increases the compatibility between PVA and GO. The theoretical blend study also led to the conclusion that the three molecules could be mixed over the entire temperature range. Overall, these results suggest that TEOS can be successfully employed for the functionalization of PVA/GO hybrid materials, as it strengthens the interaction of the organic and inorganic phases.

Wear behavior of a new composite formulation, with TEOS addition, for abrasive vitrified grinding wheels

Vitrified grinding wheels are used in many manufacturing industries to shape and finish metals and other materials in an efficient way. This work addresses a new approach with the use of tetraethyl orthosilicate solution (TEOS solution or silica sol), as an additive, in vitrified abrasive composites for grinding wheels. Different types of composite were produced using always the same materials and processing methods, but with different TEOS contents. Compared with a reference abrasive grinding wheel, the addition of TEOS promoted an improvement in the abrasive tool performance. The new formulation for vitrified abrasive composites showed better dimensional stability during processing (drying and sintering), and could be applied to the production of grinding tools with high dimensional accuracy. With the addition of 3.75 wt% of TEOS there was an increase in the strength of the matrix bonds. The porosity of the composite increased by 7% (from 43.6 to 46.9%), also improving its wear properties, with the quadrupling of the grinding ratio of the abrasive composite. In addition, the surface roughness of the composite decreased (from Ra = 22.9 to 8.4 μm) allowing to improve the surface finish of the workpieces.

Analysis of the Magnetic Properties of Fenimo/Sio2 Soft Magnetic Composites Prepared by the Sol-Gel Method with Teos Addition

Analysis of the Magnetic Properties of Fenimo/Sio2 Soft Magnetic Composites Prepared by the Sol-Gel Method with Teos Addition

Preparation and performance of nanoparticles-based anti-frosting transparent hydrophobic surfaces

Hydrophobic surface has been used for restraining frost deposition on cold non-transparent surfaces. However, anti-frosting surfaces with good transparency, esp. transparent hydrophobic surfaces are receiving more and attention from both industries and researchers. A simple method for preparing transparent hydrophobic surface is thus proposed and used to fabricate anti-frosting hydrophobic surfaces. A series of frosting experiments on transparent hydrophobic surfaces and unmodified glass surfaces were carried out under natural convection conditions. The results show that the maximum contact angle of the modified hydrophobic surface is increased by 39.3°, which means an increase of 44.1% over that of the unmodified plain glass surface. The surface properties are the best when TEOS addition is 10 mL. In the range of visible light, the surface transmittance is greater than 87%. A very special condensate droplets freezing mechanism, i.e. , the ice bridge mechanism is observed. And the frost crystal appearance time on the hydrophobic surface is more than 660 s, which is 540 s longer than that on the unmodified glass surface. The frost coverage of the hydrophobic surface is significantly smaller than that of the unmodified plain glass surface, the speed of frost propagation is only 47.5 μm/s, which is 29.6% lower than that of unmodified surface. Therefore, compared with the unmodified surface, the hydrophobic glass surface can effectively inhibit the growth of frost layer without much loss of its transparency. • Transparent hydrophobic surface was fabricated successfully by gel-sol method. • Visible light transmittance of transparent hydrophobic surface is as large as 87%. • Good anti-frosting performance of the surface is confirmed under high cold surface temperature conditions.

Cellulose Monoacetate/Tetraethyl Orthosilicate Hybrid Nanofibers for Electrochemical DNA Biosensors

Cellulose monoacetate/tetraethyl orthosilicate (CMA/TEOS) hybrid nanofibers were produced with different ratios via electrospinning and used for guanine oxidation analysis in the single strand deoxyribonucleic acid (ssDNA) molecules by electrochemical method. Nanofiber (NF) diameters for pure CMA dramatically decreased from between 2.4 µ, −306 nm to between 958-42 nm with addition of hydrochloric acid (HCl) catalyzer into the electrospinning solution. Uniform CMA nanofibers morphologies transform to more defect structures containing particular structures with the addition and increase of TEOS content in CMA electrospinning solution. Also, nanofibers’ diameters range became more fluctuated form and ultrafine nanofibers (diameters below 100 nm) existed more in the nanofiber mat. Even though the melting point was seen at CMA nanofibers, melting points were not detectable in CMA/TEOS NFs since TEOS addition does not allow an appropriate crystallization. Thermal analysis results revealed that residual contents after TGA measurement in nitrogen atmosphere were gradually increased by increasing TEOS ratio in CMA/TEOS nanofibers. ssDNA molecules were immobilized on the as-spun nanofibers and differential pulse voltammetry (DPV) measurements were carried out to investigate the guanine oxidation in ssDNA. Guanine oxidation signal intensities decreased with the initial addition of TEOS to CMA nanofibers and increases again by increasing TEOS content in CMA/TEOS hybrid nanofibers and then gradually decreases again with increasing TEOS content. The prepared CMA/TEOS hybrid nanofibers could be a promising candidate as an electrode interface for genetic molecule detection via electrochemical methods.

Stability study of all-inorganic perovskite CsPbBr3 QDs@SiO2/EVA film composites prepared by one-step

CsPbX3 (X = Cl, Br, I) all-inorganic perovskite quantum dots have attracted extensive attention from researchers recently. However, the further development is confined by serious stability problems. In this work, the CsPbBr3 QDs@SiO2/EVA films were prepared by supersaturated recrystallization, and SEM, EDS, XRD, FT-IR and PL were used to study microstructure, phase composition, and optical properties. Results show that during the preparation process, the amounts of precursor added would affect the fluorescence emission intensity of materials. The preparation method of films is simple, easy to operate, low cost, and beneficial to commercial large-scale production. In a typical synthesis, PbBr2 and CsBr are dissolved in DMF, and then oleic acid (OA) and oleylamine (OAm) as ligands are added to stabilize the DMF−PbBr2−CsBr precursor solution. When the addition of TEOS is 0.06 mL, the PL peak strength of prepared films is higher and the thickness of CsPbBr3 QDs@SiO2/EVA films is about 100 μm and flexible enough to be bent. At room temperature, the retention of fluorescence intensity of films is 67.4% after 30 d in the air, the retention is 63.6% after 40 h in the water, and the retention is 72.1% after 40 h under the UV light. EVA resins and SiO2 coating can effectively isolate the contact between quantum dots and moisture and delay the intrusion of oxygen, which significantly improves the stability of pure quantum dots.

In Situ Electrospun Zein/Thyme Essential Oil-Based Membranes as an Effective Antibacterial Wound Dressing.

Wound dressings are an important element in promoting the healing of wounds. Electrospun fibrous materials have a highly porous structure and controllable antibacterial activity and are therefore popular as potential wound dressings. However, electrospun fibrous wound dressings are usually conveniently packaged for immediate use but cannot accommodate irregularly shaped wounds, and their misuse runs the risk of causing a secondary injury to the wound. To overcome these issues, in situ electrospun zein/thyme essential oil (TEO) nanofibrous membranes are proposed as a potential type of wound dressing and applied for wound management through an in situ electrospinning process, which uses a portable electrospinning device. The as-spun zein/TEO membranes show high gas permeability up to 154 ± 20.9 m2/s and superhydrophilicity with a 0° contact angle. With the addition of TEO, good antibacterial effects are also imparted onto the membrane to prevent infection. Moreover, the in situ electrospinning can directly deposit the zein/TEO membranes onto the site of the wound to accommodate the shape of the wound with increased convenience and perceived comfort. Experiments carried out on mice suggest that the in situ electrospun zein/TEO membrane greatly promotes the wound healing process within 11 days. The study results, therefore, suggest that wound dressings in the form of in situ electrospun zein/TEO membranes can be used to facilitate wound healing.

Surface-modified polyvinyl alcohol (PVA) membranes for pervaporation dehydration of epichlorohydrin (ECH), isopropanol (IPA), and water ternary feed mixtures

Conventional distillation failed to separate a ternary azeotropic mixture of ECH, IPA and water (50/30/20w/w, %) exist in the epoxy resin manufacturing process. Thus, we prepared a PVA-tetraethyl orthosilicate organic–inorganic hybrid membrane and modified the membrane by layer-by-layer deposition of a PVAm/silicotungstic acid polyelectrolyte for the pervaporation (PV) dehydration of ECH/IPA/water mixtures. In PV experiments at 30°C, the flux decreased from 0.14 to 0.05kg m−2h−1 and separation factor increased from and 2099 to 13,320 with TEOS addition in the PVA membrane was observed. And for the layer by layer deposition on PVA-TEOS (4) membranes flux increased and separation factor decreased from 0.14 to 0.28kgm−2h−1 and 2099 to 416 with the number of layer of deposition were observed respectively. On varying the feed water content from 20 to 10wt. %, the pervaporation flux at 30°C decreased from 0.22 to 0.0066kgm−2h−1 and the separation factor increased from 1061 to 9094 was observed. By applying the Arrhenius equation, permeation activation energies of ECH and IPA (97.42 and 111.96kJmol-1, respectively) are higher than that of water (40.88kJmol−1) were reported for the layer by layer membrane.

Effect of SiO2 addition on structural and optical properties of Yb:Lu3Al5O12 transparent ceramics based on laser ablated nanopowders

Transparent 3.6 at.% Yb:Lu3Al5O12 (Yb:LuAG) ceramics are obtained by solid-state reaction synthesis at 1800 °C in vacuum for 1–5 h using Yb:Lu2O3 and Al2O3 nanopowders (mean size: ∼30 nm) produced by laser ablation and sedimentation. The nanopowders and ceramics are studied by DSC, dilatometry, SEM, XRD, Raman and optical spectroscopy. The effect of the sintering aid (tetraethoxysilane, TEOS, up to 1 wt%, equivalent to 0–0.28 wt% of SiO2 addition) on the micro-structural and optical properties of the ceramics is revealed. With the addition of TEOS, the transparency of the ceramics is improved while the growth of the grains is limited by the SiO2 solubility. For the ceramics sintered at 1800 °C for 5 h with 1 wt% of TEOS, the transmission at ∼1.1 μm is as high as 82.7% and the content of pores is 7 ppm, corresponding to a mean grain size of 14 μm. The ceramics exhibit intense Yb3+ luminescence at ∼1 μm. The maximum stimulated-emission cross-section is σSE = 2.46 × 10−20 cm2 at 1030.2 nm and the luminescence lifetime of the 2F5/2 state is 1.01 ms, close to the radiative one. The synthesized ceramics are promising for thin-disk laser elements.

Development of Poly Lactic Acid/Kitosan Elastomer with Essential Oil Addition to Improved Performance Antibacterial Materials

Consumer demand for high quality food without chemical preservatives is a challenge for the food industry. Therefore, food packaging is needed which can extend the shelf life of food products by protecting from external factors such as microorganisms, moisture, and ultraviolet light. In this study, we synthesize Poly Lactic Acid (PLA) derived from environmentally friendly materials and the addition of chitosan to produce a material that are resistant to the development of microorganisms in food packaging applications which is a new concept innovation of biodegradable active packaging, where packaging is developed this has an ability to reduce or inhibit the growth of microorganisms on the food surface. The results obtained in this study are as follows: the addition of turmeric as essential oil and chitosan have been shown to increase antibacterial activity. Elastomer biofilms produced are able to fight S.aureus and E. coli bacteria on exposure for 72 hours in an open room. They are more effective against gram-positive bacteria when compared to gram-negative. Maximum biofilm tensile strength in 4-gram chitosan variation, 0.3 mL TEO and 0.5 mL / biofilm glycerol with tensile strength of 40.01 MPa. The maximum decomposition temperature of the biofilm is obtained at 315.74°C with 4 grams chitosan variation, TEO 0.3 mL and 0.5 mL glycerol. The addition of TEO into the chitosan biofilm is also able to bind molecules of chitosan and evenly distributed molecules on the surface.

High-Performance Soya Polyurethane Networked Silica Hybrid Nanocomposite Coatings

The projected fossil fuel deposits depletion by near future and detrimental effects of petroleum products on environment has led to the development of volatile organic compound (VOC) free low molecular weight sustainable polymers, with promising applications in field of inks, adhesives, paints, and coatings. In view of this, present study reports synthesis, characterization, and anticorrosive performance of SMG-PU and modified SMG-PU through in situ formed silica networks (SMG-PU-TEOS) OIH polymer nanocomposite coatings on CS. The size of ∼30 nm silica nanonetworks were formed within SMG-PU on addition of TEOS, inducing thermal stability, hydrophobic, improved physicomechanical and corrosion resistant properties to polymer nanocomposite coatings. The corrosion protective performance of these coatings in 5% NaCl (salt mist test), 3.5% NaCl, and 3.5% HCl solutions revealed very lower Icorr values (3.8891 × 10–10 A cm–2 and 6.8756 × 10–9 A cm–2) as compared to SMG-PU (1.8159 × 10–8 A cm–2 and 9.1396 × 10–7 A...

Preparation and characterization of polyhedral oligomeric silsesquioxane (POSS) using domestic microwave oven

This paper reports the preparation and characterization of polyhedral oligomeric silsesquioxane (POSS) using a domestic microwave oven. The hybrid nanomaterials were synthesized using the hydrolytic condensation of vinyltriethoxysilane (VTES) and a VTES/tetraethyl orthosilicate (TEOS) mixture. The samples were characterized by FTIR, 1H-NMR, 29Si-NMR, GPC, SEM, TEM, WAXD and TGA. The dielectric heating of the VTES and VTES/TEOS systems enabled the production of POSS with increased yield, showing rates 47 and 59 times faster than conventional heating, respectively. The POSS VTES samples prepared by dielectric and conventional heating showed very similar chemical characteristics. However, for the POSS obtained with the addition of TEOS the same behavior was not observed, because of the selective effect occasioned by microwave-assisted synthesis. The morphological shape of the hybrid clusters is dependent on the synthesis method and the precursor type. The simple approach used in this work represents an alternative to obtaining nanomaterials more efficiently.

Microwave dielectric properties of YAG ceramics prepared by sintering pyrolysised nano-sized powders

YAG ceramics with good dielectric properties were prepared via a modified pyrolysis method, with yttrium nitrate as the yttrium source and combined aluminium sulphate and aluminium nitrate as aluminium sources, and subsequent sintering in a muffle furnace. The effects of the different aluminium sources on the powder characteristic and the impact of sintering temperature, sintering aids (TEOS) and additive (TiO2) on the dielectric properties of the ceramics were studied. The results show that well-dispersed pure YAG nano-powders can be obtained after calcination at 1000°C with an aluminium sulphate and aluminium nitrate molar ratio of 1.5:2. The relative density, permittivity (εr) and quality factor (Q×f) of the YAG ceramics increase with sintering temperature and TEOS addition. TiO2 can greatly promote τf to near-zero but decreases Q×f. The relative density, εr, Q×f and τf of the YAG–1wt% TEOS–1wt% TiO2 ceramic obtained at 1520°C are 97.6%, 9.9, 71, 738GHz and −30ppm/°C, respectively.

Electrical mobility of silver ion in Ag2O-B2O3-P2O5-TeO2 glasses.

The effect of adding TeO(2) into (100 - x)[0.5Ag(2)O - 0.1B(2)O(3) - 0.4P(2)O(5)] - xTeO(2), with 0-80 mol % TeO(2) glass, on the structural changes and electrical properties has been investigated. DSC and thermodilatomery were used to study their thermal behavior, structure was studied by Raman spectroscopy, and electrical properties have been studied by impedance spectroscopy over a wide temperature and frequency range. The introduction of TeO(2) as a third glass former to the glass network causes the structural transformation from TeO(3) (tp) to TeO(4) (tbp) which contributes to the changes in conductivity. The glasses with low TeO(2) content show only a slow decrease in dc conductivity with addition of TeO(2) due to the increase of the number of nonbridging oxygens, which increases the mobility of Ag(+) ions. The steep decrease in conductivity for glasses containing more than 40 mol % TeO(2) is a result of decrease of the Ag(2)O content and stronger cross-linkage in glass network through the formation of more Te-(eq)O(ax)-Te bonds in TeO(4) tbp units. The glasses obey ac conductivity scaling with respect to temperature, implying that the dynamic process is not temperature dependent. On the other hand, the scaling of the spectra for different glass compositions showed the deviations from the Summerfield scaling because of the local structural disorder which occurs as a result of the structural modifications in the tellurite glass network.

Selective wet etching of Si3N4/SiO2 in phosphoric acid with the addition of fluoride and silicic compounds

Various additives were added to H3PO4 in order to achieve a highly selective wet etching of Si3N4 to SiO2. Fluoride compounds such as HF, NH4F, and NH4HF2 were added to the H3PO4 in order to increase the etch rate of the Si3N4. In addition, silicic compounds, including H2SiF6, TEOS, and Si(OH)4, were added to decrease the etch rate of SiO2. The addition of the fluoride compounds into the H3PO4 increased the etch rate of the Si3N4, but the etch selectivity of the Si3N4 to SiO2 decreased due to the greater increase in the etch rate of the SiO2. Both the etch rate and the selectivity showed strong relationships with the amount of fluorine added in H3PO4. The addition of TEOS and Si(OH)4 increased the etch selectivity by reducing the etch rate of the SiO2. In particular, the addition of Si(OH)4 to H3PO4 in the presence of NH4F and NH4HF2 produced an etch selectivity greater than 104.

Microporosity development in phenolic resin-based mesoporous carbons for enhancing CO2 adsorption at ambient conditions

Soft-templating method was used to prepare mesoporous carbons. The synthesis in the presence of hydrochloric and citric acids involved resorcinol and formaldehyde as carbon precursors and triblock copolymer Pluronic F127 as a template. The as-synthesized samples underwent carbonization in flowing nitrogen at various temperatures; namely 600°C, 700°C and 800°C. Two routes were used to develop microporosity in the mesoporous carbons studied. The first one involved introduction of tetraethyl orthosilicate to the reaction system. After silica dissolution with NaOH, an increase in microporosity was observed. The second method, chemical activation with KOH at 700°C, was explored as an alternative approach to create microporosity. It is noteworthy that the TEOS addition not only led to the development of microporosity but also to some improvement of mesoporosity. The post-synthesis KOH activation resulted in more significant increase in the microporosity as compared to the samples obtained by TEOS-assisted synthesis. The mesopore volume was somewhat lower for activated carbons as compared to that in mesoporous carbons. Both methods resulted in micro-mesoporous carbons with good adsorption properties; for instance, in the case of carbons prepared in the presence of TEOS, the best sample exhibited BET surface area of 1463m2/g and the total pore volume of 1.31cm3/g. For the KOH activated carbons the best adsorption parameters were as follows: the specific surface area=1906m2/g, and the total pore volume=0.98cm3/g. Both procedures used for microporosity development afforded carbons with good adsorption properties that can be useful for applications such as CO2 adsorption, air and water purification.