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One of the best methods of extracting Vitamin A, as a helper of the immune body system and vision, was measured in supercritical carbon dioxide (SC-CO2); Mole fractions were gained at practical conditions in which the temperature was in the range of 303–323 K and the pressure range was 90–235 bar, respectively. Moreover, four Equation of States [Soave–Redlich–Kwong, Peng–Robinson, Stryjek–Vera and Dashtizadeh–Pazuki–Taghikhani–Ghotbi (DPTG)] were compared with the experimental data. Also, the mixing rules of Van der Waals (vdW1 and vdW2) selected to correlate the solubility data of vitamin A. The outcomes indicate that each of EOSs coupled with vdW2, as a method of estimating the physicochemical and critical properties, were correlated with the solubility data of vitamin A in SC-CO2 with more accuracy, in comparison with vdW1. Among the cubic EOSs, the DPTG model with vdW2 generated the most suitable correlation with the percentage average absolute relative deviation (Average Absolute Relative Deviation%) of 6.

A novel photocatalytic continuous system has been proposed for the treatment of tannery waste water, which has high levels of environmental pollutants. The purification process was performed by passing wastewater on a titanium dioxide (TiO2)-coated surface, which is continuously activated by irradiation of ultraviolet light. To improve the yield of the process, ferric chloride (FeCl3) was used as a coagulation agent. The organic and inorganic compounds, as well as the microorganisms in the tannery wastewater media, were degraded through a photocatalytic process. The results revealed that total dissolved solids and total suspended solids contents were significantly decreased from 8,450 and 8,990 mg·L−1 to 4,032 and 4,127 mg·L−1, respectively. Furthermore, the chemical oxygen demand content of the sample was reduced from 370 to 50 mg·L−1 after the addition of 100 mL of FeCl3 and 4 h of treatment. The same results were observed for the elimination of sulfate and chromium ions, which led to a decline in electrical conductivity. This suggests that introducing 100 mL of FeCl3 as the coagulation agent and continuous treatment with photocatalityc set-up could be considered as an effective method for the purification of tannery wastewaters. HIGHLIGHTS Continuous set-up fabricated for tannery wastewater treatment using photocatalytic reactions.; TiO2 photocatalyst activated by UV light for improvement of purification yield.; FeCl3, as coagulation agent, facilitated treatment by removing total dissolved solids.; Toxic ions and microorganisms were eliminated in this method.

Extra-high-performance low-level filler-loaded mixed-matrix membranes (MMMs) were fabricated by embedding a flexible cyclooligomer, calix[4]arene (CA), as a macrocyclic porous filler in two blends of a commercial polyether block amide polymer, Pebax MH 1657. Two kinds of liquid phases, PEG550 (PEG) and [OMIM][PF₆] (IL), were separately introduced into the Pebax MH 1657 matrix to prepare blended membranes for enhancing the CO₂ permeability and comparing their performance. Afterward, CA as the third generation of supramolecular hosts with high inherent affinity to CO₂ was synthesized and incorporated in the polymer blends to fabricate high-performance MMMs. The organic nature, the high compatibility of other applied additives with Pebax MH 1657 polymer, and the tiny size of CA particles were responsible for the desirable particle distribution in ternary MMMs. In the case of the Pebax/PEG550 (30 wt%)/CA (0.5 wt%) MMM, the results revealed the CO₂ permeability to be about 632.60 Barrer, with CO₂/CH₄ and CO₂/N₂ selectivities about 59.83 and 139.88, respectively. For Pebax/IL (6.5 wt%)/CA (0.5 wt%), the CO₂ permeability was about 263.82 Barrer, with CO₂/CH₄ and CO₂/N₂ selectivities about 64.39 and 152.45, respectively. Therefore, the fabricated ternary MMMs present a promising outlook for CO₂ separation, which surpasses the Robeson upper limits.

Purpose Among all forms of cancers, hepatocellular carcinoma (HCC) is the fifth most common cancer worldwide. There are several treatment options for HCC ranging from loco-regional therapy to surgical treatment. Yet, there is high morbidity and mortality. Recent research focus has shifted towards more effective and less toxic cancer treatment options. Curcumin, the active ingredient in the Curcuma longa plant, has gained widespread attention in recent years because of its multifunctional properties as an antioxidant, anti-inflammatory, antimicrobial, and anticancer agent. Methods A systematic search of PubMed, Embase and Google Scholar was performed for studies reporting incidence of HCC, risk factors associated with cirrhosis and experimental use of curcumin as an anti-cancer agent. Results This review exclusively encompasses the anti-cancer properties of curcumin in HCC globally and it’s postulated molecular targets of curcumin when used against liver cancers. Conclusions This review is concluded by presenting the current challenges and future perspectives of novel plant extracts derived from C. longa and the treatment options against cancers.

Inevitably, the terms “materials” and “products” differ from one another. To comprehend their potentiality in terms of mechanical, chemical, physical, and biological properties, the specifications of basic materials are verified in the laboratory. Then, materials are changed or contrived into products. As a definite form of a product, its thickness, shape, its inclination to migrate from one section to another, and so forth are regarded as the main extrinsic features; they are so essential in view of littering. However, the fundamental features of materials should be also pondered. Notably, they are supposed to be preserved while changing into final product procedures. The fact is that plastics are usually organic compounds which are synthetic or semisynthetic. They hold high molecular mass and along chain polymeric molecules is included in them. Holistically, plastics embrace side-linked molecular groups and some organic and inorganic blends added as additives, plasticizers, and fillers, and a main chain organic link. Elements such as carbon, hydrogen, nitrogen, oxygen, chlorine, and bromine are the building blocks of plastics. Plastics subject to important gains from the viewpoints of weight, durability, and low cost in terms of manufacture comparison with other materials. Since plastics can be molded into various size and shapes, they can be extensively practiced. Plastics have been exceedingly applied in every aspect of life and technology. Polyethylene (PE), polystyrene, polyvinyl chloride, polypropylene, and PE terephthalatete are among the plastics that are mostly put into practice. Plastics are vastly applied in every field such as health care industries, building constructions, transportations, households, and for disposals items, such as wraps, cups, spoons, trays plates, and so forth. Notably, all the mostly used plastics cannot be recycled. As a result, plastics are accumulated in landfills. Then, they are discharged in water. Henceforth, they do not decompose in the environment. Thus, environment and its varied ecosystems are endangered. One of the main global concerns is plastic pollution in the sea. They are found everywhere. In every square kilometer, almost 580,000 plastic pieces can be concentrated. Between 1000 and 3000 tons of plastic floating in the Mediterranean Sea has been reported. This contamination is due to the physical/mechanical degradation of macroplastics in landfills that produce microplastics that are transferred directly to rivers, seas, and oceans via leachate. Also, additives found in plastic formulations are not normally covalently bonded to polymer chains and can therefore leak from plastics and enter the marine environment. Plastics that enter the marine environment can also absorb persistent organic pollutants due to the hydrophobic properties of these compounds, or they can be a vector agent for the spread of harmful organisms living on plastic surfaces. © 2022 Elsevier Inc. All rights reserved.

There is an undeniable growing number of diabetes cases worldwide that have received widespread global attention by many pharmaceutical and clinical industries to develop better functioning glucose sensing devices. This has called for an unprecedented demand to develop highly efficient, stable, selective, and sensitive non-enzymatic glucose sensors (NEGS). Interestingly, many novel materials have shown the promising potential of directly detecting glucose in the blood and fluids. This review exclusively encompasses the electrochemical detection of glucose and its mechanism based on various metal-based materials such as cobalt (Co), nickel (Ni), zinc (Zn), copper (Cu), iron (Fe), manganese (Mn), titanium (Ti), iridium (Ir), and rhodium (Rh). Multiple aspects of these metals and their oxides were explored vis-à-vis their performance in glucose detection. The direct glucose oxidation via metallic redox centres is explained by the chemisorption model and the incipient hydrous oxide/adatom mediator (IHOAM) model. The glucose electrooxidation reactions on the electrode surface were elucidated by equations. Furthermore, it was explored that an effective detection of glucose depends on the aspect ratio, surface morphology, active sites, structures, and catalytic activity of nanomaterials, which plays an indispensable role in designing efficient NEGS. The challenges and possible solutions for advancing NEGS have been summarized.

More than five decades have been invested in understanding glucose biosensors. Yet, this immensely versatile field has continued to gain attention from the scientific world to better understand and diagnose diabetes. However, such extensive work done to improve glucose sensing devices has still not yielded desirable results. Drawbacks like the necessity of the invasive finger‐pricking step and the lack of optimization of diagnostic interventions still need to be considered to improve the testing process of diabetic patients. To upgrade the glucose‐sensing devices and reduce the number of intermediary steps during glucose measurement, fourth‐generation glucose sensors (FGGS) have been introduced. These sensors, made using robust electrocatalytic copper nanostructures, improve diagnostic efficiency and cost‐effectiveness. This review aims to present the essential scientific progress in copper nanostructure‐based FGGS in the past 10 years (2010 to present). After a short introduction, we presented the working principles of these sensors. We then highlighted the importance of copper nanostructures as advanced electrode materials to develop reliable real‐time FGGS. Finally, we cover the advantages, shortcomings, and prospects for developing highly sensitive, stable, and specific FGGS.

Highlighting mixed matrix membrane (MMM) susceptibility in improving the membrane performance along with established p-tert-butylcalix[4]arene (CA) ability in CO2 sorption, Pebax-1657-based MMMs ha...

Combined heating and power (CHP) systems can be a favorable addition to the geothermal power plants since the generated heating commodity can be addressed for wide-range of mountainous districts. Regarding this consequential demand, two innovative CHP systems for the Sabalan geothermal in Iran are designed which were based on organic Rankine cycle (ORC) and Kalina cycle (KC). The plausibility of the introduced monolithic CHP systems is examined from thermodynamic and economic vantage points. Later, multi-criteria optimization via genetic algorithm procedure is accomplished considering major thermodynamic and economic parameters as objective functions. It was exhibited that the recommended ORC-based CHP system could generate overall optimum heating load and net electricity of 5151 kW and 3697 kW, correspondingly as well as achieving energetic efficiency of 61.38% and exergetic efficiency of 36.91%. On the other side, the KC-based CHP system generated overall heating load and net electricity of 2867 kW and 3912 kW, correspondingly, achieving energetic efficiency of 46.12% and exergetic efficiency of 32.52%. The outcomes of the second-law analysis portrayed that among all constituents, condenser attributed as the utmost destructive part of the systems due to the regasification processed firstly occurred through this constituent, followed by the generator. Also, to examine how the introduced set-ups react to any external disturbances, a thoroughgoing sensitivity examination around the basic operating input parameters was fulfilled. It is discovered that the energetic efficiency of the ORC-based CHP system could be maximized with condensation temperature, whilst the exergetic efficiency of the KC-based CHP system could be maximized with ammonia concentration.

In this paper, a novel comprehensive permeation model for mixed matrix membranes (MMMs) is introduced. This model shows the importance of understanding and developing a more reliable model for the permeation behavior of MMMs containing porous filler nanoparticles. A new method is established to provide a more precise/large‐scale three‐dimensional MMMs geometry. The required number of spherical porous fillers in random/nonuniform positions in the polymer matrix is calculated. Interfacial equilibrium constant (K) at the polymer/filler interfaces was adjusted as the concentration ratio of the diffusing penetrants (C2 and C1) at the interface, respectively. In this case, the K values are changed by varying the intended gaseous concentration due to their permeation through the MMM. Hence, its effect on penetrants effective diffusion coefficient was examined. Then, the obtained results were evaluated with similar experimental data, which showed much consistency. Therefore, the accurate calculation method for MMMs permeability was governed for the entire range of the operating pressures in MMMs. The results showed that the permeability of MMMs increases with increasing filler particle size. On the other hand, variations that occur in the MMM permeability at various particle size were much more distinct at higher loadings. Moreover, some well‐known analytical permeation models were used to compare and validate the model's permeability results. It can be concluded that this model provides a method for more precise and realistic design of MMMs as well as to better construe the large number of related experimental data. © 2019 Society of Chemical Industry and John Wiley & Sons, Ltd.

Multigeneration systems (MGSs) driven by renewable sources are proved as cutting-edge technologies for multiple productions purposes to curb greenhouse gas emissions. With this regard, a novel geothermal-based MGS is proposed to produce multiple commodities of cooling, heating, power, and hydrogen, simultaneously, using liquefied natural gas (LNG) as cold energy recovery. The system is composed of an organic Rankine cycle (ORC), an ejector refrigeration cycle (ERC), an LNG power generation system, and a proton exchange membrane (PEM) electrolyzer system. To demonstrate the feasibility of the proposed MGS, energy, exergy, and exergoeconomic analysis are employed as the most effective tools for the performance assessment of the system. It is found that the proposed MGS can produce cooling capacity, heating capacity, net output power, and hydrogen of 1020 kW, 334.8 kW, 1060 kW, and 5.43 kg/h, respectively. In this case, the thermal efficiency, exergy efficiency and total SUCP (sum unit cost of the product) of the MGS are calculated 38.33%, 28.91%, and 347.9 $/GJ, respectively. Furthermore, condenser 2 is introduced as the main source of irreversibility of the proposed MGS by exergy destruction ratio of 58.98%. Moreover, a comprehensive parametric study is carried out and it is concluded that the SUCP of the system can be optimized based on the geothermal inlet temperature. In addition, it is demonstrated that a higher thermal efficiency can be obtained by increasing the turbine 2 expansion ratio, evaporator temperature, and geothermal temperature or decreasing of the generator terminal temperature difference, turbine 1 expansion ratio, pump 3 pressure ratio, and condenser temperature. In the same vein, a higher exergy efficiency can be attained at high turbine 1 expansion ratio, turbine 2 expansion ratio, evaporator temperature, and pump 3 pressure ratio or low generator terminal temperature difference, geothermal inlet temperature, and condenser temperature.

For the past two centuries, the range of synthesized organic compounds have increased excessively including raw materials, plastics, fuels, detergents, and other useful substances. However, pollution and other hazards have resulted from the production of these compounds as well as remaining in the environment after usage, which is a serious concern. There are plenty of categories of organic compounds that could be considered as the main issues in the current era, such as polychlorinated biphenyls, dichlorodiphenyltrichloroethane, polybrominated diphenyl ethers, dechlorane plus, and decabromodiphenyl ethane. Polychlorinated biphenyls could be found in the capacitors, transformers, and electric fluids. Polybrominated diphenyl ethers, dechlorane plus, and dichlorodiphenyltrichloroethane are known as fire retardant in many industries like fabrics and polymers. In fact, three various sources are known to be responsible as being the most polluting in industries including military wastes, industrial activities, and agriculture chemical materials. On the other hand, petroleum products, polycyclic aromatic hydrocarbons, aromatic compounds, dioxins, most of the chloro-derivatives of acetic acids, phosphate derivatives, carbamates, organometallic compounds, and the most highlighted one, plastics or other degradable resistant polymers. Furthermore, the importance of pesticides and fertilizers in modern agriculture are well-known for everyone. Agrochemical compounds save the crop production from being lost for 70% during production and storage steps. The other sources of the organic pollutant compounds such as fuels in vehicles as well as urban and industrial wastes are more familiar than any demands for definition. © 2022 Elsevier Inc. All rights reserved.

This study aims to precisely model vapor phase concentration and bubble pressure in correlating alcohol-hydrocarbon mixtures to accurate assessment with effects from literature by employed Patel-Teja equation of state and together with Wong-Sandler mixing rules. Even though other intricate equations have been used for some selected systems, it is the first time that a systematic approach for measuring hydrocarbon-alcohol mixtures in the range of low to moderate pressures has been practiced by this research. Results show that models employed in this work, average-absolute deviations are fewer than the previous EoSs for alcohol-hydrocarbons binary mixtures. The complex models calculate bubble pressure and vapor phase concentration respectively with 2.25% and 3.25% of average-absolute deviations, whiles our models show a better result for them (respectively, 0.00 % and 0.47% averagely).

Liquid air energy storage (LAES) is a promising but under-developing electricity storage concept for large-scale applications, which has gained a lot of attention in recent years. No geographical restrictions, acceptable cost-effectiveness level, and high energy density are some of the main advantages of this technology. On the other hand, the immature state-of-the-art, and lower power-to-power round-trip efficiency compared to other competitors are referred to as its main drawbacks which should be addressed for the successful development of this concept. The current research proposes a novel hybrid design for the LAES to improve its electrical efficiency and to introduce it as a multi-generating unit being capable of tri-generation of power, heat, and potable water. The proposed hybrid system results in an overall efficiency of over 71% which is already ∼23% better than the conventional design of a stand-alone LAES. Thermodynamic analysis of the proposed hybrid system is performed; the simulation results are validated using the existing data in the literature. The multi-objective optimization algorithm is developed to optimize the system configuration and operating characteristics. 88.6 MWh off-peak renewable-based electricity is stored during 8 h to provide 52.8 MWh electrical energy during 4 h of the peak period. Also, 59 m3 potable water and 938.8 m3 hot water are produced during 12 h of system operation.

The operating condition for an experimental setup is usually determined using design of experiment method. However, it does not guarantee to achieve the best possible condition. Therefore, as the novelty, this study aims at using multi-objective optimization for this purpose, by which it could be sure that the best possible condition will be determined. In addition, energy, technical, environmental, and economic indicators have not been taken into account at the same time for finding the best condition before, whereas, as another novelty, they are all considered here. The multi-objective optimization is employed to determine the optimum operating temperature and pressure in an industrial process of toluene production as a solvent. Hildebrand solubility parameter, as well as economic benefit and consumed energy per unit mass of product, have been considered as the objective functions, while carbon dioxide emission has also been taken into account as the environmental function that is optimized to acquire a cleaner production line. According to the results, compared to the design of experiment method, the Hildebrand solubility parameter has been enhanced from 13.32 to 16.11 MPa0.5. Moreover, the benefit increased from 0.0488 to 0.0708 $ kg−1 while the energy production per mass of product had a 71.66% reduction. Acquiring a much cleaner production line to prepare the solvent is also guaranteed by employing the multi-objective optimization where the carbon dioxide emission has been reduced from 0.0793 to 0.0225 kg per unit mass of the prepared solvent. Decreasing both temperature and pressure from 534.15 to 381.65 K, and from 2.50 to 1.10 MPa, respectively, is another big advantage of the employed multi-objective optimization method, which leads to a safer condition.

Thermal efficiency and emission of a gas-turbine cycle were improved through consideration of heat and mass recirculations. In this regard, three potential scenarios were investigated: using lone mass circulation, only heat recirculation, and both types of recirculation at the same time. In each scenario, the maximum potential improvement was found by multi-objective optimization. Furthermore, in the case of only heat circulation scenario, the best heat recirculator was chosen by comparing a tubular with a plate-fin heat exchanger (PFHE) a well-known decision-making method which is called analytical hierarchy process (AHP). Finally, AHP method was employed again to select the superior scenario for improving the gas cycle. According to the results, the best scenario was the scenario in which heat recirculation with PFHE was used in the absence of mass recirculation. In this scenario, thermal efficiency and NOx emission were improved 4.20 and 17.94%, respectively. The payback time of the investment of the modification was also about 62 days. Moreover, due to the shortage of power in the case of mass recirculation, this scenario was found to be desirable when there is extra capacity in power generation, and the goal is reducing emissions as much as possible.

Mixed matrix membranes were made of polysulfone and Matrimid® polymers, and SiO2 and TiO2 nanoparticles in order to improve the efficiency of polymeric membrane in gas separation and review the efficiency of membrane separation process, laboratory. The modeling results of selectivity and permeability of gases O2, N2, CO2 and CH4 were discussed for different membranes. Another objective of this study was to submit a report on the importance of the statistical analysis and modeling in design and optimizing mixed matrix membranes to separate gas. The D-optimal method was applied to model and optimize the selectivity and permeability due to the main parameters. The obtained results indicated that the permeability of all gases demonstrated an ascending trend when the nanoparticles were increased. Under optimized conditions, the permeability of the gases O2, N2, CO2, CH4 in the membrane of PSF (12)/SiO2 (13.82) was 2.49, 1.113, 12.82 and 0.885 Barrer, respectively. A statistical method was practiced in the current research to design, optimize and separate gas membranes through effective efficiency for different applications.

In this study, a comprehensive time-dependent mathematical model for gas separation through the facilitated transport membranes (FTMs) is presented. The model results have been validated with independent CO2/N2 binary gas mixture experiments in DEA-impregnated PVA membranes. In the proposed model, non-equal diffusion coefficients of the carrier/complex and equilibrium constant for the chemical reaction kinetics between the carrier/permeant in the FTM have been considered. In addition, a method to compute the diffusion coefficients, which depend on the concentration of each component in the FTM, is presented. Moreover, effect of carrier concentration, feed partial pressure, kinetics of reversible chemical reactions and membrane performances depending on operating condition have been analyzed. Owing to accurate calculation of physical–chemical parameter involved, this model is much more executive comparing to previous works. In addition, the real condition of the reaction kinetics and influencing of diffusion parameters of the components in FTMs, have been investigated. The predicted selectivity and permeability revealed good conformity with experimental data; with standard deviation (SD) 8.57% and 12.87%, respectively. In conclusion, this model with significant validity would be predictive in cases for the entire range of diffusion-limit to a chemical-limit regime where the experimental data, geometry condition, physical–chemical property of parameters is not available.

Highlighting enhanced properties of polymers provided by dual-curing, self-healing coatings have been prepared via Diels-Alder and urethane formation reactions. These two orthogonal reactions were performed by functionalization of hydroxyl-terminated polybutadiene with furan dangling groups through thiol-ene reaction. In other words, the presence of the furan groups along with the terminal hydroxyl groups of HTPB made it possible to undergo in both urethane formation and Diels-Alder cycloaddition reactions, simultaneously. Remarking the effect of the Diels-Alder reaction on the self-healing ability of the samples, the proper bismaleimide compound has been selected by the DSC test. Moreover, a novel tetrafuran compound has been synthesized as crosslinking agent to improve the mechanical strength of the prepared coating and their self-healing properties. Evaluating the microscopic and macroscopic scales showed that the prepared coatings exhibited good healing properties as well as their mechanical properties. The microscopic imaging confirmed that the created scratches vanished after the healing process in all samples. Furthermore, the healed samples were displayed at least 50 % of their initial strength in the tensile test. Additionally, the results revealed that the coatings mechanical strength was reinforced from 1.34 to 2.30 MPa by introducing tetrafuran crosslinking agent in their matrix.

An extended approach to determine Hildebrand solubility parameter (HISP) of pure 1-alkanols by precise calculation of the isothermal compressibility coefficient and heat capacities is proposed. The approach is introduced during its implementation for four pure polar 1-alkanols, namely 1-heptanol, 1-octanol, 1-nonanol, and 1-decanol. Having described the approach, the prediction ability of that is compared with the previous methods for calculation of the properties. Comparisons show that for all the three mentioned properties, the proposed approach provides significantly better predictions. The mean absolute error for prediction of the isothermal compressibility coefficient, isobaric heat capacity, and HISP by the proposed approach are 1.77, 1.32, and 0.17% (for 1-heptanol), 1.54, 1.11, and 0.18% (for 1-octanol), 2.90, 0.97, and 0.28% (for 1-nonanol), and 1.39, 1.61, and 0.39% (for 1-decanol), respectively. In addition to checking the accuracy of the proposed approach, to investigate the impacts of temperature and pressure as two key parameters on HISP of 1-alkanols, sensitivity analyses are conducted. The results of sensitivity analyses show that same as the non-polar substances, in the case of polar compounds, increase in pressure leads to an increase in HISP. Furthermore, when temperature does not change, HISP approaches a constant value at high pressures. Moreover, the relationship between temperature and HISP is linear.

A number of HZSM-5 catalysts modified with 5 wt% Mg, Na, Zr, and Al as well as others modified with 5–60 wt% Zn prepared by wet impregnation. These materials were characterized by the NH3-TPD, XRF, and XRD analyses and tested in a slurry reactor to determine their activities in dehydration of methanol solution in kerosene. Reactions were carried out at 230°C and 19 bar for 4 h of residence time in the reactor. Results showed that in the first series, the catalyst modified with Zr and in the second series, the one modified with 10 wt% Zn led to the highest methanol conversion. It was deduced that elimination of strong acid sites and partial replacement of active cations in the HZSM-5 zeolite lattice enhanced the performance and improved resistance against formation of hydrocarbons and other by-products such as olefins all of which acted as coke precursors. In order to determine the activation energy, the rate equation of Bercic and Levec was utilized and assumptions consistent with reaction conditions cons...

In this research, the cross-linking of diethanolamine (DEA) impregnated poly(vinyl alcohol) (PVA) on polytetrafluoroethylene (PTFE) by glutaraldehyde (GA) with different blend compositions (GA/PVA: 0.5, 1, 3, 5, 7 ratio%) was performed in the absence of an acid catalyst and organic solvents in order to avoid any interference in CO2 facilitation reaction with DEA. The fabricated membranes were characterized by differential scanning calorimetry (DSC), Fourier transform infrared (FTIR) and scanning electron microscopy (SEM). Furthermore, the effects of cross-linking agent content, feed pressure and composition as well as stability on CO2/CH4 transport properties were investigated in both pure and mixed gas experiments. The cross-linked membranes showed reasonable CO2/CH4 permselectivities in comparison with uncross-linked membranes. The best-yield CO2-selective membranes (DEA-PVA/GA(1 wt%)/PTFE) represented the best CO2/CH4 selectivity of 91.13 and 665 for pure and mixed gas experiments, respectively.

In this paper, polyvinyl alcohol (PVA) membranes impregnated with amines (monoethanolamine and diethanolamine) were prepared for CO2/N2 separation. The cross-linking of DEA impregnated PVA by glutaraldehyde (GA) with different mass ratios (GA/PVA: 0.5, 1, 3, 5, 7%) were investigated with no use of acid catalyst or organic solvents. The effects of the amine type-concentration, cross-linking agent content, and feed pressure as well as stability were examined in both pure and mixed gases. Generally, CO2/N2 performance through the DEA-PVA membranes was higher than that of MEA-PVA membranes. The fabricated membranes were characterized by differential scanning calorimetry (DSC), Fourier transform infrared (FTIR) and scanning electron microscopy (SEM). The cross-linked membranes showed reasonable CO2/N2 permselectivities in comparison with uncross-linked membranes and these are recommended for high performance membrane for CO2/N2 separation. The best-yielding membranes (DEA-PVA/GA(1 wt%)/PTFE) represented the greatest CO2/N2 selectivity of 122.04 and 907.06 for pure and mixed gas experiments, respectively.

The drive toward greater application of membrane has resulted in its rapid development in natural gas processing industry. In this work, amine-mediated membranes were tailored for CO2 removal from CO2/CH4 stream. The effects of various parameters such as amine concentration, microporous support, feed pressure and composition were examined to study the permeation behavior of pure and mixed gases. Generally, CO2 transport through the DEA-PVA membranes was higher than that of MEA-PVA membranes for approximately 70%. The membrane containing 15 wt% DEA and 35 wt% MEA revealed higher permselectivity. CO2 permeance enhancement of amine-PVA membranes in comparison with neat PVA membrane, confirmed that CO2-amine reaction was the dominant transport mechanism. Additionally, with increasing feed pressure, CO2/CH4 permselectivity decreased due to carrier saturation. However, lower partial pressure of CO2 was in favor of reaction mechanism in pure and mixed gas tests. On the other hand, CH4 is not significantly affected by feed pressure confirming that solutiondiffusion is the governing transport mechanism. Additionally, PTFE support with higher wettability showed better performance (18%) regardless of amine type, concentration and feed pressure. DEA-PVA membrane has exhibited good stability during 2 weeks, unlike MEA-impregnated membrane, which was probably due to carrier degradation over time. POLYM. ENG. SCI., 54:1268–1279, 2014. V C 2013 Society of Plastics Engineers

In this article, permeation models for nanocomposite polymeric membranes (NCPMs) filled with nonporous particles are discussed and two new models for prediction of effective permeability of NCPMs are proposed. To derive these models, the presence of interfacial layer at the surface of the nanofiller particles as well as the impact of two important phenomena namely creating void volumes and increasing free volume at the interface layer are taken into account. The capability of the models for prediction of reliable results is checked against available experimental data on permeability of NCPMs and is also compared with other presented models for such membranes. The new proposed models show profound superiority over the well known models such as “Bruggeman model in limit” which offers fairly good prediction for NCPMs.

In this study the gas separation performance of polyimide/polysulfone (PI/PSF) mixed matrix membranes filled with zeolite ZSM-5 particles is investigated. The membranes are prepared by solution-casting method and utilized to determine the permeation rates of N2, O2, CO2 and CH4 through pure polymers as well as composite membranes. The membranes are characterized by SEM, TGA and FTIR. The effects of polymers ratio and weight fraction of zeolite on permeation and selectivity of the gases are discussed. Polymers ratio in the mixed matrix have assumed values of 100% PSF, 70/30 (PSF/PI), 50/50, 30/70 and 100% PI while ZSM-5 loadings are varied between 0 and 20 wt.%. SEM results showed that fabricated membranes have homogeneous structure. With pure polyimide membrane, O2 permeability increased from 0.69 Barrer for membrane without zeolite up to 0.73 and 0.89 Barrer for membranes with 10% and 20% zeolite, respectively. Within blended matrices, the minimum permeability (maximum selectivity) and the most homogeneous matrix structure were related to the matrix with 50/50 weight percent of two polymers.