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排序方式: 共有1293条查询结果,搜索用时 15 毫秒
41.
Mahsa Heidari Ali Akbar Safekordi Maryam Ghaedian Amin Shafeghat 《Korean Journal of Chemical Engineering》2013,30(3):700-705
An experimental study was conducted to investigate the extraction of oxidized sulfur compounds from gas oil. Solvents used for this purpose included acetone, acetonitrile, methanol and propanol. The effect of solvent concentration, solvent to gas oil ratio, temperature, time and number of stages was studied. To select the best solvent and conditions for extraction, two criteria were considered: high desulfurization and more hydrocarbon recovery. Results showed that extraction time and temperature have no significant effect. Methanol for low ability of extraction of oxidized sulfur compounds and propanol for low hydrocarbon recovery were excluded from further experiments. After the tests, the optimum conditions for extraction were determined to be 85% acetone, solvent/feed ratio of 1, two stages extraction in ambient temperature and enough time for mixing. In this condition 85% of sulfur compounds of gas oil containing 1,670 ppmw S were separated and 95% of gas oil was recovered. 相似文献
42.
The thermo-mechanical properties of poly (l-lactide) (PLLA) biodegradable polymer reinforced with PLLA grafted from multiwalled carbon nanotubes (MWCNT-g-PLLA)s are characterized. The crystallinity of PLLA polymer matrix affected by MWCNT-g-PLLAs is illuminated. For this purpose, the PLLA chains are covalently grafted from the sidewall of aminated MWCNTs. Then, the MWCNT-g-PLLAs/PLLA composite films are prepared by solution casting using chloroform as solvent. It is found that the MWCNT-g-PLLAs well dispersed in PLLA matrix. The mechanical properties of PLLA enhanced gradually with the increasing concentrations of MWCNT-g-PLLAs up to 2 wt%. The MWCNT-g-PLLAs increase the glass transition temperature (T g) and melting point of PLLA as revealed by the curves from differential scanning calorimeter (DSC). In addition, the dynamic mechanical analysis (DMA) results show that the T g and Young modulus of PLLA increase with the increment in the concentrations of MWCNT-g-PLLAs. Due to the homogenous dispersion of MWCNT-g-PLLAs and the van der Walls force between grafted PLLA chains on the sidewall of MWCNTs and the PLLA matrix chains, the chain stiffness in amorphous phase of PLLA increases. In addition, the MWCNT-g-PLLAs as heterogeneous nucleation agents increase the crystallinity of PLLA. 相似文献
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A new, efficient and recoverable heterogeneous catalyst was successfully synthesized by functionalization of mesoporous silica FSM-16. The FSM-16/CPTMS-Rh- 相似文献
45.
Propane dehydrogenation on a commercial Pt-Sn/Al2O3 catalyst in a Pd-Ag membrane reactor is considered. A mathematical model is developed to evaluate the performance of the catalytic membrane reactor for the process of propane dehydrogenation. Design and operating conditions are systematically evaluated for key performance metrics such as propane conversion, propylene selectivity, hydrogen selectivity, and hydrogen recovery under different operating conditions. The results confirm that the high performance of the membrane reactor is related to the continuous removal of hydrogen from the reaction zone to shift the reaction equilibrium towards the formation of more propylene and hydrogen. 相似文献
46.
Seyed Mohammadreza Miraboutalebi Mohammad Peydayesh Maryam Bagheri Toraj Mohammadi 《化学工程与技术》2020,43(6):1214-1223
The potential of a novel α-Fe2O3/polyacrylonitrile (PAN) hybrid composite adsorbent to eliminate methylene blue (MB) from aqueous solution was evaluated. PAN was selected as the base composite. The presence of α-Fe2O3 as nanophotocatalyst on the surface of PAN introduced an efficient photocatalytic hybrid composite adsorbent for degrading MB. Effects of α-Fe2O3 nanopowder loading, pH, temperature, MB initial concentration, solar light, and contact time were investigated. Langmuir, Freundlich, and Temkin isotherms were applied to analyze the adsorption behavior. The Freundlich equation provided the best correlation with experimental data. Pseudo-first-order, pseudo-second-order, and intraparticle models were employed. Thermodynamic studies indicated an endotherm and spontaneous adsorption process in a defined temperature range. 相似文献
47.
Saharnaz Ahmadi Maryam Farokhi Parisa Padidar Mojtaba Falahati 《International journal of molecular sciences》2015,16(8):17289-17302
In this study the effect of surface modification of mesoporous silica nanoparticles (MSNs) on its adsorption capacities and protein stability after immobilization of beta-lactoglobulin B (BLG-B) was investigated. For this purpose, non-functionalized (KIT-6) and aminopropyl-functionalized cubic Ia3d mesoporous silica ([n-PrNH2-KIT-6]) nanoparticles were used as nanoporous supports. Aminopropyl-functionalized mesoporous nanoparticles exhibited more potential candidates for BLG-B adsorption and minimum BLG leaching than non-functionalized nanoparticles. It was observed that the amount of adsorbed BLG is dependent on the initial BLG concentration for both KIT-6 and [n-PrNH2-KIT-6] mesoporous nanoparticles. Also larger amounts of BLG-B on KIT-6 was immobilized upon raising the temperature of the medium from 4 to 55 °C while such increase was undetectable in the case of immobilization of BLG-B on the [n-PrNH2-KIT-6]. At temperatures above 55 °C the amounts of adsorbed BLG on both studied nanomaterials decreased significantly. By Differential scanning calorimetry or DSC analysis the heterogeneity of the protein solution and increase in Tm may indicate that immobilization of BLG-B onto the modified KIT-6 results in higher thermal stability compared to unmodified one. The obtained results provide several crucial factors in determining the mechanism(s) of protein adsorption and stability on the nanostructured solid supports and the development of engineered nano-biomaterials for controlled drug-delivery systems and biomimetic interfaces for the immobilization of living cells. 相似文献
48.
Farshid Hassanzadeh Sahar Maaleki Jaleh Varshosaz Ghadam Ali Khodarahmi Maryam Farzan Mahboubeh Rostami 《Iranian Polymer Journal》2016,25(11):967-976
A novel thermosensitive folic acid (FA)-targeted succinylated poly (ethylene-co-vinyl alcohol) (EVOH) (EVOHS-FA) nanocarrier was synthesized for the specific delivery of epirubicin (EPI) to MCF-7 breast cancer cell line. Three different ratios of synthesized EVOH-Suc were reacted with FA. The structure of the desired products (EVOHS40-FA, EVOHS60-FA and EVOHS80-FA) was confirmed by 1H NMR and FTIR techniques. Nanoparticles were obtained by nano-precipitation procedure using DMSO/H2O as solvent/anti-solvent. The particle size, zeta potential, entrapment efficacy and in vitro release profile of the final formulations in different temperatures were measured. The optimized nanoparticles had the particle size of 214 ± 8.5 nm, zeta potential of ?29.6 mV, PDI of 0.198 ± 0.04, and a high encapsulation efficiency that released the drug efficiently within 450 h at the temperature of 40 °C compared to 37 °C. The morphology of nanoparticles was studied by scanning electron microscopy. The in vitro cytotoxicity was evaluated using the MTT assay on MCF-7 cell lines in response to temperatures of 37 and 40 °C. The MTT assay indicated that the targeted nanoparticles carrying EPI were significantly more cytotoxic than the non-targeted nanoparticles and the free drug at 40 °C. 相似文献
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Tiziana Nardo Valeria Chiono Piergiorgio Gentile Maryam Tabrizian Gianluca Ciardelli 《国际聚合物材料杂志》2016,65(14):741-750
Poly(DL-lactide-co-ε-caprolactone) (PLCL) and poly(DL-lactide-co-glycolide) (PLGA) blends of various compositions were prepared. Fractured sections of PLCL/PLGA blends did not evidence phase separation and blend glass transition temperatures suggested some degree of blend compatibility. The elastic modulus showed a negative deviation from the additive law of mixture. Superior biocompatibility in terms of fibroblast NIH 3T3 cell adhesion and proliferation, better mechanical properties, and a more homogeneous phase were obtained with PLCL/PLGA 25/75 blend. Rapid degradation of PLCL phase (4–8 weeks) in PLCL/PLGA 25/75 blend led to a porous structure, which makes it a potential candidate for drug delivery systems. 相似文献