Silicalite-1 Membrane: Synthesis, Modification, Characterization And Its Performance For The Reactive Separation Of Para-Xylene From Xylene Isomers

Reactive separation of para-xylene from xylene isomers in a catalytic membrane reactor depends on the right choice of catalytic membrane. This membrane should not only catalyze xylene isomerization reaction but also separate para-xylene (p-xylene) from its isomers (ortho-xylene (o-xylene) and meta-xylene (m-xylene)). In the present study, silicalite-1 and two types of acid-functionalized silicalite-1 membranes: (1) propylsulfonic acid functionalized silicalite-1 membrane and (2) arenesulfonic acid-functionalized silicalite-1 membrane were synthesized on disc type �-alumina support, pre-coated with mesoporous silica layer

Bulk CO2/CH4 separation for offshore operating conditions using membrane process

The increasing demands of natural gas pushes energy industries to explore the reservoirs contain high CO2 concentration and impurities including heavy hydrocarbons. High efficiency of using membrane technology in CO2-natural gas separation has extended its potential application to offshore environment. Due to the limited studies related with the separation of CO2 under offshore conditions, the present work has investigated the separation performance of a commercial membrane in removing bulk CO2 from methane at elevated pressure condition. A wide range of offshore operating conditions including pressure from 10 to 50 bar, CO2 concentration from 25 to 70% and temperature of 30oC, 40oC and 50oC were studied. High relative CO2 permeance and relative CO2/CH4 selectivity were observed when the pressure and the CO2 concentration increased. This work, therefore substantial is to bridge the gap and facilitates the application of membrane technology for offshore operating conditions

Prediction of CO2 Permeability in NH2-MIL-53(Al)/Cellulose Acetate Mixed matrix Membranes using Theoretical Models

Estimation of CO2 permeability of mixed matrix membranes (MMMs) using models has importance for the design of membrane separation system. In the current article, the previously reported models were used for the calculations of CO2 permeability through new type of MMMs, NH2-MIL-53(Al)/CA. It was found that modified Maxwell model demonstrated the absolute average error (AARE %) of 1.66%, which is lower than the AARE% obtained from the other theoretical models. Besides, the results also showed that AARE% of models for the prediction of CO2 permeability was in the order of modified Maxwell model < Lewis-Nielsen model < Fleski model < Bruggeman model < Pal model< modified Fleski model < Maxwell model. Therefore, it can be concluded that modified Maxwell model is more accurate compared to other theoretical models for the prediction of CO2 permeability through NH2-MIL-53(Al)/CA MMMs

Mixed Matrix Membranes Comprising of ZIF-8 Nanofillers for Enhanced Gas Transport Properties

AbstractIn the current research, mixed matrix membranes (MMMs) comprising of 5, 10, 15 and 20 wt% of zeolitic imidazolate framework-8 (ZIF-8) were incorporated into 6FDA-durene polyimide phase. The effect of ZIF-8 loading on the membrane performance of CO2 and CH4 separation was investigated. The excellent compatibility and good distribution of ZIF-8 nanofiller in 6FDA-durene polyimide phase even at higher ZIF-8 loading up to 20 wt% has resulted in the increment of CO2 permeability and CO2/CH4 selectivity compared to pure membrane. In this work, 6FDA-durene loaded with 10 wt% ZIF-8 demonstrated impressive CO2 permeability of 1426.75 Barrer with CO2/CH4 selectivity of 28.70, which successfully surpassed the Robeson 2008 upper bound

Experimental Study of CO₂ Plasticization in Polysulfone Membrane for Biogas Processing

Polymeric membranes have emerged for biogas processing to remove CO2 from CH4. Nonetheless, it is also acknowledged that polymeric membranes have the tendency to sorb highly condensable CO2, which consequently swells the polymeric matrix, typically at operating condition higher than the plasticization pressure. The swelling increases void spaces for transport of gas penetrants, which results in an increment in permeability of all gas components at the cost of substantial decrease in membrane selectivity. Despite observations of the end results of plasticization, it is found that many transport property studies include only permeability measurements near ambient conditions. Complementary information on the individual contributions of the sorption and diffusion coefficients to the overall performance typically at non-ambient operating conditions is rarely reported. Therefore, in present study, experimental study has been conducted to fabricate polysulfone (PSF) film. Validity of the developed polysulfone membrane has been verified through characterization and validated with gas transport behavior of published results. Subsequently, transport properties of CO2 though the PSF membrane at varying operating temperatures has been elucidated. The dual mode sorption and partial immobilization models have been employed to quantify the gas transport properties of noncondensable CH4 and condensable CO2 through PSF membrane

A Sugarcane-Bagasse-Based Adsorbent Employed for Mitigating Eutrophication Threats and Producing Biodiesel Simultaneously

Eutrophication is an inevitable phenomenon, and it has recently become an unabated threat. As a positive, the thriving microalgal biomass in eutrophic water is conventionally perceived to be loaded with myriad valuable biochemical compounds. Therefore, a sugarcane-bagasse-based adsorbent was proposed in this study to harvest the microalgal biomass for producing biodiesel. By activating the sugarcane-bagasse-based adsorbent with 1.5 M of H2SO4, a highest adsorption capacity of 108.9 ± 0.3 mg/g was attained. This was fundamentally due to the surface potential of the 1.5 M H2SO4 acid-modified sugarcane-bagasse-based adsorbent possessing the lowest surface positivity value as calculated from its point of zero charge. The adsorption capacity was then improved to 192.9 ± 0.1 mg/g by stepwise optimizing the adsorbent size to 6.7–8.0 mm, adsorption medium pH to 2–4, and adsorbent dosage to 0.4 g per 100 mL of adsorption medium. This resulted in 91.5% microalgae removal efficiency. Excellent-quality biodiesel was also obtained as reflected by the fatty acid methyl ester (FAME) profile, showing the dominant species of C16–C18 encompassing 71% of the overall FAMEs. The sustainability of harvesting microalgal biomass via an adsorption-enhanced flocculation processes was also evidenced by the potentiality to reuse the spent acid-modified adsorbent

Synthesis And Characterization Of Pure-Silica- Zeolite-Beta Membrane

The semiconductor industry needs low dielectric constant (low k-value) materials to more advance microprocessor and chips by reducing the size of the device features. In fabricate this context, a new material with lower k value than conventional silica ( k = 3.9 - 4.2 ) is needed in order to improve the circuit performance. As per the recent International Semiconductor Technology plan, a low-k material with a k = 1.6 will be needed by 2010. The choice of the inorganic zeolite membrane is an attractive option for low k material and suitable for microprocess application.  In the present study, a pure silica zeolite beta membrane coated on the non-porous stainless steel support was synthesized using in situ crystallization of a gel with the composition of  SiO2 : 0.6 TEAOH : 0.6 HF : 10.1 H2O. The crystallization was carried in the presence of tetraethylammonium hydroxide TEA(OH) as structure directing agent, fumed silica, HF and deionized water at pH value of 9. The crystallization under hydrothermal conditions at 130oC was carried out for the time period of 14 days. The membrane was characterized by X-Ray Diffraction ( XRD ),  Thermogravimetric Analysis ( TGA ), Nitrogen Adsorption and Scanning Electron Microscope ( SEM ) .   SEM micrographs show highly crystalline, truncated square bipyramidal morphology of pure silica zeolite beta was coated on the non-porous stainless steel support. The membrane dielectric constant, k-value was measured as 2.64 which makes it suitable for the microprocessor applications

Synthesis And Characterization Of Pure-Silica- Zeolite-Beta Membrane

The semiconductor industry needs low dielectric constant (low k-value) materials to more advance microprocessor and chips by reducing the size of the device features. In fabricate this context, a new material with lower k value than conventional silica ( k = 3.9 - 4.2 ) is needed in order to improve the circuit performance. As per the recent International Semiconductor Technology plan, a low-k material with a k = 1.6 will be needed by 2010. The choice of the inorganic zeolite membrane is an attractive option for low k material and suitable for microprocess application.  In the present study, a pure silica zeolite beta membrane coated on the non-porous stainless steel support was synthesized using in situ crystallization of a gel with the composition of  SiO2 : 0.6 TEAOH : 0.6 HF : 10.1 H2O. The crystallization was carried in the presence of tetraethylammonium hydroxide TEA(OH) as structure directing agent, fumed silica, HF and deionized water at pH value of 9. The crystallization under hydrothermal conditions at 130oC was carried out for the time period of 14 days. The membrane was characterized by X-Ray Diffraction ( XRD ),  Thermogravimetric Analysis ( TGA ), Nitrogen Adsorption and Scanning Electron Microscope ( SEM ) .   SEM micrographs show highly crystalline, truncated square bipyramidal morphology of pure silica zeolite beta was coated on the non-porous stainless steel support. The membrane dielectric constant, k-value was measured as 2.64 which makes it suitable for the microprocessor applications

Fabrication of multilayer composite hollow fiber membrane comprising NH2-MIL-125 (Ti) for CO2 removal from CH4

The presence of CO2 has created significant challenges in natural gas processing in order to meet consumer's specifications and pipeline transportation. Membrane separation is among the most effective approaches in CO2 separation from natural gas mainly to its energy efficiency. This study investigates the alternate technique for enhancing the performance of hollow fiber membrane in CO2 removal from CH4. A new type of composite hollow fiber membrane is fabricated by dip-coating of polymer solution comprising various loadings of NH2-MIL-125 (Ti) in PEBAX onto PDMS coated-polysulfone (PSf) hollow fiber. The morphology and elemental mapping analysis of the resultant membranes were characterized via scanning electron microscope (SEM) and energy dispersive X-ray (EDX), respectively. SEM images showed that no major voids or clusters were observed between the two phases of polymer and filler. Improved CO2 and CH4 gas permeance were found for composite membranes, as compared to PSf membrane coated only by PDMS and PEBAX solutions. Besides, highest improvement of CO2/CH4 ideal selectivity was obtained for composite membrane loaded with 10 wt% of filler. High porosity and high CO2 affinity of NH2-MIL- 125 (Ti) are the main reasons for the enhancement of CO2 removal from CH4. Hence, further research work is necessary to explore the performance of this membrane at various operating conditions such as temperature, flow rate, and CO2 feed concentration

Performance of Multilayer Composite Hollow Membrane in Separation of CO2 from CH4 in Mixed Gas Conditions

Composite membranes comprising NH2-MIL-125(Ti)/PEBAX coated on PDMS/PSf were prepared in this work, and their gas separation performance for high CO2 feed gas was investigated under various operating circumstances, such as pressure and CO2 concentration, in mixed gas conditions. The functional groups and morphology of the prepared membranes were characterized by Fourier transform infrared spectroscopy (FTIR) and field emission scanning electron microscopy (FESEM). CO2 concentration and feed gas pressure were demonstrated to have a considerable impact on the CO2 and CH4 permeance, as well as the CO2/CH4 mixed gas selectivity of the resultant membrane. As CO2 concentration was raised from 14.5 vol % to 70 vol %, a trade-off between permeance and selectivity was found, as CO2 permeance increased by 136% and CO2/CH4 selectivity reduced by 42.17%. The membrane produced in this work exhibited pressure durability up to 9 bar and adequate gas separation performance at feed gas conditions consisting of high CO2 content