Bis(triethoxysilyl)ethane Research Articles

Hydrogen (H2)/Toluene (TOL) Separation via One and Two Stages of the Bis(triethoxysily)ethane (BTESE) Membranes.

The separation ability of bis(triethoxysilyl)ethane (BTESE) membranes for hydrogen (H2) purification from hydrogen (H2)/toluene (TOL) gas mixtures after a methylcyclohexane (MCH) dehydrogenation process was investigated via one-stage and two-stage membrane processes. This study revealed that BTESE membranes of varied pore sizes (0.4, 0.5, and 0.7 nm) in a one-stage configuration can manage to achieve a H2 purity ~99.9%. However, the TOL concentrations fell within a wide range, ranging from 280 to 5441 ppm. A primary goal of this research was to lower the TOL concentration in the permeate stream below 200 ppm. Hence, by applying the two-stage membrane, it was demonstrated that the TOL concentration in the permeate stream could be lowered below 200 ppm.

Development of robust polysesquioxane/polymer dual-network hybrid membranes for flue gas carbon capture

In the present study, robust organic/inorganic dual-network membranes were designed by combining the advantages of polysesquioxane with superior thermal and structural stabilities, and polyether with outstanding CO2-philic and film-forming abilities. Specifically, a typical polysesquioxane precursor, bis(triethoxysilyl)ethane (BTESE), was selected to generate the inorganic-based amorphous network via a hydrolysis and condensation process, during which polyethylene glycol (PEG) was introduced to form the organic network. The Si-O-Si network derived from BTESE could provide excellent mechanical stability, while the repeat polar ethylene oxide units contained in PEG were expected to furnish a strong affinity toward CO2 through dipolar-dipolar interactions. In comparison to individual membranes, the dual-network membranes presented both attractive CO2/N2 separation performance and improved structural stability. These dual-network membranes proposed in this work hold great potential in industrial flue gas carbon capture and the strategies for designing such inorganic–organic dual-network membranes could be extended to other robust inorganic–organic hybrid films/materials.

Preparation of Polysilsesquioxane-Based CO2 Separation Membranes with Thermally Degradable Succinic Anhydride and Urea Units

New polysilsesquioxane (PSQ)-based CO2 separation membranes with succinic anhydride and monoalkylurea units as thermally degradable CO2-philic units were prepared by the copolymerization of a 1:1 mixture of [3-(triethoxysilyl)propyl]succinic anhydride (TESPS) or [3-(triethoxysilyl)propyl]urea (TESPU) and bis(triethoxysilyl)ethane (BTESE). The succinic anhydride and monoalkylurea units underwent thermal degradation to form ester and dialkylurea units, respectively, with the liberation of small molecules (e.g., CO2 and NH3) under N2 atmosphere. The effects of thermal degradation on the performance of the obtained membranes were investigated. The TESPS-BTESE- and TESPU-BTESE-based membranes calcined at 250 °C and 200 °C exhibited good CO2/N2 permselectivities of 20.2 and 14.4, respectively, with CO2 permeances of 7.7 × 10−8 and 7.9 × 10−8 mol m−2·s−1·Pa−1, respectively. When the membranes were further calcined at elevated temperatures of 350 °C and 300 °C, respectively, to promote the thermal degradation of the organic units, the CO2 permeances increased to 1.3 × 10−7 and 1.2 × 10−6 mol m−2·s−1·Pa−1 (3.9 × 102 and 3.6 × 103 GPU), although the CO2/N2 permselectivities decreased to 19.5 and 8.4, respectively. These data indicate that the controlled thermal degradation of the organic units provides a new methodology for possible tuning of the CO2 separation performance of PSQ membranes.

Bis(triethoxysilyl)ethane (BTESE)-Organosilica Membranes for H2O/DMF Separation in Reverse Osmosis (RO): Evaluation and Correlation of Subnanopores via Nanopermporometry (NPP), Modified Gas Translation (mGT) and RO Performance.

A 40 cm length Bis(triethoxysilyl)ethane (BTESE) membrane having different pore sizes was successfully prepared by changing the number of coating times for gas permeation (GP) and organic solvent reverse osmosis (OSRO) separation study. It was found that BTESE-6 membranes prepared through six-time coating consisted of small-sized pores in the range 0.56 to 0.64 nm estimated using modified Gas Translation (mGT) method and 0.59 to 0.67 nm estimated by nanopermporometry (NPP) method, respectively. These membranes demonstrated a high DMF rejection, RDMF > 95% with total flux, Jv total > 5 kg m-2 h-1 at operating condition feed pressure, Pf: 8 MPa; feed temperature, Tf : 50 °C; and feed flowrate, Qf : 30 mL/min; and they exhibited a high degree selectivity of He/SF6 in the range of ~ 260-3400 at a permeation temperature 200 °C. On the other hand, the larger pore sizes of the BTESE-4 membranes (pore size estimates > 0.76 nm to 1.02 nm) exhibited low DMF rejection and a low degree selectivity of He/SF6 around ~30% and 25, respectively, at the same operating condition as BTESE-6. Both GT and NPP methods can be considered as an indicator of the measurement membrane pore size. From this study, it was found that He and SF6 gases can be some of the potential predictors for water and DMF permeance. Furthermore, by comparing our OSRO membrane with other PV membranes for DMF/H2O separation, our BTESE-6 membranes still exhibited high flux in the range of 3-6 kg m-2 h-1 with a separation factor H2O/DMF in the range of 80-120.

An Upgraded Protocol for the Silanisation of the Solid Phase for the Synthesis of Molecularly Imprinted Polymers

The introduction of solid-phase imprinting has had a significant impact in the molecular imprinting field, mainly due to its advantage of orienting the template immobilisation, affinity separation of nanoMIPs and faster production time. To date, more than 600 documents on Google Scholar involve solid-phase synthesis, mostly relying on silanes mediating template immobilisation on the solid phase. Organosilanes are the most explored functionalisation compounds due to their straightforward use and ability to promote the binding of organic molecules to inorganic substrates. However, they also suffer from well-known issues, such as lack of control in the layer’s deposition and poor stability in water. Since the first introduction of solid-phase imprinting, few efforts have been made to overcome these limitations. The work presented in this research focuses on optimising the silane stability on glass beads (GBs) and iron oxide nanoparticles (IO-NPs), to subsequently function as solid phases for imprinting. The performance of three different aminosilanes were investigated; N-(6-aminohexyl) aminomethyltriethoxy silane (AHAMTES), 3-Aminopropyltriethoxysilane (APTES), and N-(2-aminoethyl)-3-aminopropyltriethoxysilane (AEAPTES), as well as studying the effect of dipodal silane bis(triethoxysilyl)ethane (BTSE). A stable solid phase was consequently achieved with 3% v/v AEAPTES and 2.4% BTSE, providing an upgraded protocol from Canfarotta et al. for the silanisation of the solid phase for molecular imprinting purposes.

Preparation of nanocomposite aromatic polyamide reverse osmosis membranes by in-situ polymerization of bis(triethoxysilyl)ethane (BTESE)

Bis(triethoxysilyl)ethane (BTESE) nanoparticles were incorporated into aromatic polyamide (PA) membranes via in-situ polymerization to prepare BTESE nanocomposite PA (BTESE-TFN) membranes for reverse osmosis. In-situ polymerization was utilized to produce BTESE nanoparticles with high dispersion in PA membranes by adding BTESE as precursors into PA membranes for in-situ polymerization. Organic bridged -C-C- in BTESE provided enhanced compatibility between BTESE nanoparticles and PA membranes. The BTESE-TFN membranes showed durability with stable RO performance for more than 96 h because of the high dispersion of BTESE nanoparticles and enhanced compatibility between BTESE nanoparticles and PA membranes. The BTESE nanoparticles increased surface roughness, thickness, hydrophilicity of PA membranes. The BTESE nanoparticles changed surfaces of PA membranes to looser structure with more pores and gaps. However, low loadings of BTESE nanoparticles in the BTESE-TFN membranes were observed due to low reactivity of Si-OC2H5 groups in BTESE. Even so, salt rejection of prepared TFN-0.12 membrane was slightly improved to 96.81%, compared with that of prepared pristine PA membrane. The TFN-0.12 membrane showed water flux of 1.6 L/(m2•h•bar), 25% higher than the water flux of pristine PA membrane because of enlargement of pore sizes in BTESE nanoparticles, formation of a loose and rough membrane surface and enhancement of hydrophilicity of the membrane surface. Furthermore, modification of organic bridged groups in the BTESE exhibited great potential to further optimize the water flux and durability of BTESE-TFN membranes.

Periodic Mesoporous Organosilica Nanoparticles for CO2 Adsorption at Standard Temperature and Pressure.

(1) Background: Due to human activities, greenhouse gas (GHG) concentrations in the atmosphere are constantly rising, causing the greenhouse effect. Among GHGs, carbon dioxide (CO2) is responsible for about two-thirds of the total energy imbalance which is the origin of the increase in the Earth’s temperature. (2) Methods: In this field, we describe the development of periodic mesoporous organosilica nanoparticles (PMO NPs) used to capture and store CO2 present in the atmosphere. Several types of PMO NP (bis(triethoxysilyl)ethane (BTEE) as matrix, co-condensed with trialkoxysilylated aminopyridine (py) and trialkoxysilylated bipyridine (Etbipy and iPrbipy)) were synthesized by means of the sol-gel procedure, then characterized with different techniques (DLS, TEM, FTIR, BET). A systematic evaluation of CO2 adsorption was carried out at 298 K and 273 K, at low pressure. (3) Results: The best values of CO2 adsorption were obtained with 6% bipyridine: 1.045 mmol·g−1 at 298 K and 2.26 mmol·g−1 at 273 K. (4) Conclusions: The synthetized BTEE/aminopyridine or bipyridine PMO NPs showed significant results and could be promising for carbon capture and storage (CCS) application.

Homogeneous sub-nanophase network tailoring of dual organosilica membrane for enhancing CO2 gas separation

Dual organosilica membranes were synthesized to investigate the effects of differing molar ratios of bis (triethoxysilyl) ethane (BTESE)/glycidyl Polyhedral oligomeric silsesquioxane (glycidyl POSS) on the membrane performance. The reaction mechanism behind CO2 capture using the organosilica membranes under ambient conditions was also investigated. A facile in-situ framework synthesis approach was introduced for the copolymerization reaction of dual organosilica. BTESE has a smaller molecular size than that of glycidyl POSS, and the Si–C–C–Si linkage is the main structure contributing to its high CO2 affinity. Additionally, the dimensional and mechanical stability were maintained at high doping levels owing to the inclusion of glycidyl POSS. Consequently, the free volume of the resulting hybrid networks increased owing to the cage structure and high cross-link density, which was attributed to the coexistence of epoxy ring-opening polymerization and condensation polymerization. The characterization and permeation tests revealed that the 1B0.5P gel with the best copolymerization effect exhibits a high CO2 permeance of 5.74 × 10−8 mol m−2 s−1 Pa−1 at 25 °C and ideal selectivity values of 11.61, 37.55 and 63.67 for CO2/H2, CO2/CH4 and CO2/N2, respectively. Moreover, a new analytical technique was proposed to investigate the surface microstructure of organosilica membranes for the first time using optical microscopy.

Controlled organosilica networks via metal doping for improved dehydration membranes with layered hybrid structures

• bis(triethoxysilyl)ethane (BTESE)-derived sols were doped with metal ions (Al and Zr) • Metal doped BTESE sols were coated on polymer support forming layered-hybrid structure. • Metal doped BTESE layered hybrid membranes improved PV dehydration performance. • Zr-BTESE showed water permeance > 10 -6 mol/(m 2 s Pa) with H 2 O/IPA > 10,000. A layered hybrid membrane consisting of an organosilica top layer on a polymeric nanoporous substrate was successfully fabricated using bis(triethoxysilyl)ethane (BTESE)-derived organosilica sols doped with metal ions (Al and Zr). These membranes were applied to the dehydration of aqueous alcohol solutions including methanol (MeOH), ethanol (EtOH) and isopropanol (IPA). Metal-doped BTESE sols and gels were characterized via dynamic light scattering analysis (DLS), Fourier Transform Infrared spectroscopy (FT-IR), X-ray Photoelectron Spectroscopy (XPS), the isotherms of N 2 sorption, laser scanning confocal microscopy (LSM), and scanning electron microscopy (SEM). During the dehydration of an IPA solution at 105 °C, the separation factors for Al-BTESE- and Zr-BTESE-derived membranes reached 8,000 and 10,000, respectively, which exceeded the separation factor for undoped BTESE membranes and indicates that doping with metal ions improves the dehydration performance of layered-hybrid membranes. In addition, Zr-BTESE-derived membranes prepared via the rinse method showed water permeance of 1.8 × 10 -6 mol m −2 s −1 Pa −1 , which is sufficiently high and compares favorably to that of polymer substrates. These membranes also showed a separation factor that was higher than 10,000. Correlations among the permeance ratios for H 2 O/MeOH, H 2 O/EtOH, and H 2 O/IPA were successfully predicted using modified gas translation (mGT) and bimodal pore models.

Synthesis of hydrophobic silica membranes derived from propyl trimethoxy silane and bis(triethoxysilyl)ethane for separation of volatile organic compounds from aqueous solutions

Separation and recovery of volatile organic compounds (VOCs) from aqueous solutions are important in recycling VOCs and in wastewater treatment. In recent years, pervaporation (PV) separation with a hydrophobic membrane has drawn considerable attention as an alternative to distillation for separating and recovering VOCs from aqueous solutions. In this study, a hydrophobic propyl-functionalized silica membrane, having a high affinity for ethyl acetate (EA), was prepared from propyl trimethoxy silane and bis(triethoxysilyl)ethane (BTESE) without using a molecular template. The effects of the BTESE contents in the silica precursor on the membrane properties were examined. The hydrophobic silica membrane prepared from a silica sol with a BTESE content of 7.5 mol% had an EA flux of 2.55 kg m−2 h−1 and separation factor of 95.5 for PV of a 5 wt% EA aqueous solution at 25 °C. These values are the same as or greater than those of hydrophobic silica membranes prepared with cetyltrimethylammonium bromide as the molecular template, indicating our proposed method without using templates has great potential in simplifying the process for the production of hydrophobic silica membranes.

A selective organosilica membrane for ethyl acetate dehydration by pervaporation

AbstractOrganosilica bis(triethoxysilyl) ethane (BTESE) membranes were explored for pervaporation dehydration of binary and ternary mixtures of ethyl acetate (EA) by undiluted sol coating combined with flash firing. Three BTESE membranes (M1, M2, and M3) were fabricated on macroporous supports by varying BTESE concentrations (0.5, 2.5, and 5 wt% BTESE, respectively) in polymer sols. The membranes were characterized by DLS, SEM, FTIR, XRD, contact angle, AFM, and pervaporation performance to discuss the effect of the BTESE contents in the polymer sol on the formation and dehydration performance of resulting organosilica membranes. It was found that 5 wt% loading of BTESE led to a highly selective membrane for dehydration of EA/H2O mixture. Among the synthesized membranes, M3 delivered flux of 0.84 ± 0.05 kg.m−2.h−1 with a selectivity of >10,000 for EA/H2O mixture (98/2 wt%) at 60°C. The time course of pervaporation dehydration for the EA/H2O mixture (95/5 wt%) confirms the stability of BTESE membrane in the investigated time period of 120 h. Further, the membrane exhibited excellent selectivity larger than 10,000 for separation of ternary mixtures (90/2/8 wt%) of ethyl acetate/ethanol/water and n‐propyl acetate/isopropanol/water respectively, the composition of which is similar to the top product of the distillation column used in the industrial esterification process. The best separation performance and excellent acid stability of BTESE membranes in this study suggest that the simple synthesis protocol of undiluted sol coating and flash firing will provide a cost‐effective, quick, and efficient synthesis route for practical membrane based applications.

Sequentially bridged biomimetic graphene-based coating via covalent bonding with an effective anti-corrosion/wear protection for Mg alloy

The industrial applications of Mg and its alloys are restricted by their poor corrosion resistances, owing to the rapid dissolution and hydrogen evolution behaviors. In this study, a sequentially bridged reduced graphene oxide (RGO)/bistriethoxysilylethane (BTSE) coating is successfully grafted on the surface of Mg alloy substrate, to simultaneously inhibit the corrosion and wear behaviors. It exhibits well-aligned biomimetic nacre-like “bricks and mortar” structure connected by covalent bonding networks, consisting of the Si-O-C bonds between the RGO sheets and the Si-O-Si bonds derived from BTSE self-crosslinking reactions. The reduced porosity and defects lead to a high continuity and integrity of the RGO/BTSE coating, which decreases the corrosion rate by an order of magnitude compared with bare Mg substrate and RGO coated sample, owing to the enhanced barrier effect and weakened galvanic corrosion. In addition, the hybrid coating also performs well anti-wear property due to the intrinsic lubrication of RGO sheets, which can protect the substrate from friction and wear. The wear rate decreases from 3.5 × 10−3 mm3N-1 m-1 of bare Mg alloy to 5.13 × 10-5 mm3N-1 m-1 of RGO/BTSE coated sample. The interlayer slipping between the RGO sheets effectively decreases friction resistance, although the incorporation of BTSE slightly increases their shear resistance.

Solvent effects on diffusion channel construction of organosilica membrane with excellent CO2 separation properties

In this work, bis (triethoxysilyl) ethane (BTESE)-derived organosilica membranes were fabricated via the sol-gel method. To obtain organosilica membranes with high perm-selectivity, the network of the membrane was tailored by using different solvents in the preparation of the BTESE-derived sol with different pore sizes and network structures. A solvent with small polarity and a small dielectric constant (εr) can lead to outstanding single gas separation performance on the membrane structure, because the precursors are completely hydrolyzed and effectively stacked into a dense structure, which is beneficial for forming a suitable network for gas separation. The influence of the solvent and membrane thickness on the BTESE-derived membrane were evaluated to determine the mechanism responsible for the separation; this mechanism was found to be controlled not only by molecular sieving but also by selective surface diffusion. The results show that the BTESE-derived membrane prepared using tetrahydrofuran as the solvent exhibited a small network with an optimum thickness (three coating cycles) and led to a high ideal selectivity for CO2/CH4 and CO2/N2, with selectivity values of 33 and 38, respectively; additionally, the permeance of CO2 was 6.32 × 10−8 mol m−2 s−1 Pa−1 at 25 °C.

Chemical-free cleaning of fouled reverse osmosis (RO) membranes derived from bis(triethoxysilyl)ethane (BTESE)

The aim of this work was to study the fouling and cleaning behavior of bis(triethoxysilyl)ethane (BTESE)-derived organosilica membranes, which is a new class of RO membranes that feature chlorine tolerance and thermal stability. The foulants used in this study included bovine serum albumin (BSA) and sodium alginate (SA), which are typical examples of effluent organic matter (EOM). Sodium dodecyl sulfate (SDS) and dodecyltrimethyl ammonium bromide (DTAB) surfactants served as typical industrial waste. With the EOM foulants, BSA fouling occurred at a pH that approximated its iso-electric point (IEP), and the fouling became more severe with the addition of electrolytes into the SA solution. In both cases, however, the fouled BTESE membrane was recovered with the use of deionized water (DIW). The fouling was more pronounced in the presence of DTAB by comparison with SDS surfactants. Surprisingly, in all tests, within 30 min and without the need of chemical agents, the integrity of the fouled BTESE membranes was recovered by applying water at a temperature of at least 80 °C.

Characterization and corrosion protection of nano-titanium dioxide doped BTSE-GPTMS sol–gel coating on cast Al–Si alloy

A hybrid organic–inorganic sol–gel coating was prepared on the surface of cast aluminum–silicon (Al–Si) alloy via dip coating method to improve the anticorrosion ability. In the present work, bis(triethoxysilyl) ethane (BTSE) and 3-glycidoxypropyl-trimethoxysilane (GPTMS) were employed as the precursors to prepare hybrid sol–gel (BG) coating. Nano titanium dioxide (nano-TiO2) was introduced to improve the corrosion resistance of the coating. The microstructures of the BG/nano-TiO2 (BG-T) coating was characterized by scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), and Fourier-transform infrared (FT-IR) spectroscopy. The results showed that there was a chemical reaction between nano-TiO2 and BG coating and a complete defect-free coating formed on the surface of Al–Si alloy. Moreover, there were a few only minor cracks appeared on the surface of BG-T coating after 15 days immersion in 3.5 wt.% NaCl solution. The corrosion resistant performances of the coatings were evaluated by the electrochemical tests. The results showed that the nano-TiO2 particles elevated the corrosion potential and depressed the corrosion current, thereby improved the corrosion resistance. The long-term immersion tests of BG and BG-T coating further showed that the BG-T coating possesses an excellent long-term stability for corrosion protection.

HCl modification and pervaporation performance of BTESE membrane for the dehydration of acetic acid/water mixture

Membrane pervaporation has gained much attraction for high level purity of acetic acid from water because of energy saving and ecofriendly operation compared with distillation and extraction. However, fabricating membranes with high stability, selectivity and permeation flux for dehydration of acetic acid by pervaporation is highly demanded. In this work, hybrid silica membranes were fabricated using bis(triethoxysilyl) ethane (BTESE) as a precursor through sol gel route. Further modification was done as solid post HCl treatment for the synthesized BTESE membrane aiming to improve separation performance of the BTESE membranes for dehydration of acetic acid. The effect of HCl exposure time (30, 100, and 150 min) to the synthesized BTESE membranes was investigated to get optimum treatment conditions with lower separation tradeoff. In our investigation HCl treatment for about 100 min was found suitable in order to maintain permeation flux with higher selectivity. For the pervaporation performance to dehydrate acetic acid/water (90/10 wt%) at 80 °C, the synthesized BTESE membrane showed total flux of 2.47 kg m−2 h−1 with separation factor about 350 but HCl treated (100 min) BTESE membrane showed almost double separation factor up to 780 with somehow reduced flux (2.07 kg m−2 h−1). Both the membranes (synthesized and HCl treated BTESE) showed good stability within the investigated time of 150 h at 80 °C.

Preparation of robust RO membranes for water desalination by interfacial copolymerization of bis[(triethoxysilyl)propyl]amine and bis(triethoxysilyl)ethane

Bridged polysilsesquioxane membranes have been expected as robust RO membranes for water desalination. However, water permeability of the membranes was not sufficiently high. In the present work, we studied interfacial copolymerization of bis[(triethoxysilyl)propyl]amine (BTESPA) and bis(triethoxysilyl)ethane (BTESE), which resulted in ~10 times higher water permeance of the membrane than that of the BTESPA homopolymer membrane with keeping NaCl rejection at nearly the same level. It was also found that the copolymerization with BTESE improved the thermal stability and chlorine resistance of the membranes.

Purification of Pharmaceutical Solvents by Pervaporation through Hybrid Silica Membranes.

Solvents purification mainly used in pharmaceutical field such as acetone and methyl ethyl ketone (MEK) were performed through hybrid silica membranes and from binary and multi-components mixtures. Two hybrid silica membranes—zirconia doped bis(triethoxysilyl)methane and bis(triethoxysilyl)ethane (BTESE)—were studied. Flux, permeance, and separation factor were evaluated depending on temperature, composition, and number of organic compounds in the feed. Dehydration tests of acetone were operated at 30 and 45 °C following by acetone and MEK purification at 50 °C from multi-components hydro-organic mixtures where hydrophilic compounds (water, methanol) but also hydrophobic (dichloromethane (DCM) and/or toluene) were present. Results showed that the presence of Zr nanoparticles affected flux and improved selectivity in the case of dehydration. Experiments related to acetone and MEK purification, revealed a mass transfer alteration and a decrease of performance, from 99 to 97 wt% and from 98 to 95 wt% respectively, when the number of compounds in the initial feed grown up and more precisely, in the presence of DCM and toluene thus highlighting a possible coupling effect.

Tailoring the microstructure and permeation properties of bridged organosilica membranes via control of the bond angles

Sol-gel-derived organosilica membranes with different linking groups consisting of 2 carbon atoms (ethane, ethylene, and acetylene) were fabricated using bis(triethoxysilyl)ethane (BTESE), bis(triethoxysilyl)ethylene (BTESEthy), and bis(triethoxysilyl)acetylene (BTESA). No research group has ever proposed tailoring the microstructure and permeation properties of bridged organosilica membranes as a way to control the bond angles. In this study, however, we found that increases in the Si–O–Si and Si–C–C bond angles contributed to the formation of a loose and uniform structure, which was suggested by the blue shift of Si–O–Si and Si–C–C bonds in the FT-IR spectra. BTESA membranes featured a more open and accessible pore structure, which was suitable for the separation of C3H6/C3H8. The present study provides a novel way to design the microstructure and permeation properties of organosilica membranes via controlling the bond angles in the network structure.

Fabrication of highly selective organosilica membrane for gas separation by mixing bis(triethoxysilyl)ethane with methyltriethoxysilane

In the present study, the mixtures of bis(triethoxysilyl)ethane (BTESE) and methyltriethoxysilane (MTES) were proposed to design highly selective hybrid silica membranes for gas separation by the sol-gel method. The role of MTES in the hybrid membranes was investigated by changing the ratio of the two precursors. The membrane derived from mixture of 1 BTESE and 3 MTES exhibited the highest H2 and CO2 permeance with 7.99 × 10−7 mol m−2 s−1 Pa−1 and 3.53 × 10−7 mol m−2 s−1 Pa−1, respectively. In contrast, the superior selectivity was achieved on the membrane derived from mixture of 1 BTESE and 2 MTES, in which the H2/N2, H2/CH4, CO2/N2, and CO2/CH4 were found to be 64.4, 73.6, 28.5, and 32.6, respectively, which indicated that the structures of BTESE-MTES hybrid membranes can be adjusted by tuning the ratios of MTES to BTESE. Moreover, the membranes also performed well in the binary-component mixture gases and high-temperature test.