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Open Access Article
1 - Aerogels, three-dimensional nanostructures: Synthesis methods, characterization and applications
Morteza Namvar Mostafa Mahinroosta Ali AllahverdiIn recent years, aerogels attracted more attention due to their outstanding properties and potential applications in a wide variety of technological fields. Aerogels are three-dimensional porous networks or materials with a porous structure obtained from wet gels, where MoreIn recent years, aerogels attracted more attention due to their outstanding properties and potential applications in a wide variety of technological fields. Aerogels are three-dimensional porous networks or materials with a porous structure obtained from wet gels, where the solvents are replaced by air. A critical step in aerogel formation is the drying of the hydrogel. Many methods have been used to dry aerogel, the most common, safest, and cheapest method among the methods is ambient pressure drying. Due to the high-cost synthesis of monolithic aerogels, in recent years, researchers focused on the preparation of porous aerogels with modern drying methods on a large scale. In this article, aerogel, its types, history, characteristics, classification, preparation methods, properties, and applications of this interesting material are introduced. Aerogels are used in new technical applications as efficient thermal insulation, catalyst, energy storage material, water treatment adsorbent, and sound absorbent. Aerogels are also used in biomedicine and sensors. A discussion on the challenges, limitations, and urgent need to develop new technologies for aerogel production is presented. Manuscript profile -
Open Access Article
2 - Abstract
Aerogels, three-dimensional nanostructures: Synthesis methods, characterization and applications Namvar, M. Mahinroosta, A. Allahverdi Synthesis of layered double hydroxide nanostructures for adsorption of crystal violet dye from aqueous solutionsAhmad Raeisi, Saei MoreAerogels, three-dimensional nanostructures: Synthesis methods, characterization and applications Namvar, M. Mahinroosta, A. Allahverdi Synthesis of layered double hydroxide nanostructures for adsorption of crystal violet dye from aqueous solutionsAhmad Raeisi, Saeid Asadpour, Narges Sarmast, Masoumeh Kooravand Investigation of temperature effect on composite membrane synthesis with the growth of nanoparticles of zeolitic imidazolate framework-8 via chemical vapor depositionHassannia Golsefid, O. Alizadeh, F. Dorosti Study on the biodegradation of SMR rubber to reduce the environ mental wastes: The effects of curing system, filler and oilMohammadian-Geza Nanostructures prepared from natural ilmenite mineral for rapid degradation of furazolidone in heterogeneous Fenton processHaghighat, M. Fathinia, S. Fathinia Low temperature ethanol vapor sensor based on H-CeO2/Fe nanocom posite: Ultra-sensitive, selective and repeatable performanceE. Yosefian, S. Samadi, Kh. Kalateh, M. Yousefi, A. Parsa Improving the Performance of N719 Based Dye-Sensitized Solar Cell by Application of Polypyrrole/Polyaniline Conductive Polymers as a Counter ElectrodeMahdavinia, G. Kiani, A. Karimzad Ghavidel Determination of thermodynamic equilibrium conditions of ethane and propane gas hydrates using a direct and fast empirical methodIrandoukht, H. Brijanian Investigation of simultaneous removal of Basic Orange 2 dye and Ni (II) from aqueous solutions by modified nanoclay in a continuous washing system using response surface methodology (RSM) Geroeeyan, A. Niazi, E. Konoz Investigation on correlation between the content of palmitic acid methyl ester obtained by transesterification of natural rubber’s extracted lipids and cure characteristics of rubber compounds using gas chromatography – mass spectroscopyEildari, M. Malekzadeh, M.-M. Saber Tehrani, F. Motiee Investigating the effect of zeolite catalyst in the co-pyrolysis of low density polyethylene and poplar wood Behnam , M. Gholizadeh Manuscript profile -
Open Access Article
3 - Synthesis of layered double hydroxide nanostructures for adsorption of crystal violet dye from aqueous solutions
Ahmad Raeisi vanani Saeid Asadpour Narges Sarmast Masoomeh KooravandThe presence of crystal violet dye in various industries wastewater causes environmental pollution and various diseases in humans and other organisms. Therefore, research about the elimination or destruction of this pollutant is necessary. In present study, the efficien MoreThe presence of crystal violet dye in various industries wastewater causes environmental pollution and various diseases in humans and other organisms. Therefore, research about the elimination or destruction of this pollutant is necessary. In present study, the efficiency of layer double hydroxides modified with sodium dodecyl sulfate (LDH/SDS) as adsorbent was studied to remove this pollutant from wastewater. After synthesis of the adsorbent, it was characterized with instrumental techniques such as X-ray diffraction (XRD), Fourier transformation of infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). The effect of parameters such as pH, contact time, and initial concentration was studied with experimental design. Langmuir, Freundlich, and Tamkin's equations were estimated in order to find the best isotherm model for absorption data. Experimental data were fitted with Pseudo-First-Order, Pseudo-Second-Order, and interparticle diffusion kinetic models, and the best kinetic model was presented. The validity of equation was confirmed with the results of experimental design and their statistical analysis. Analysis of the data showed that the adsorption of crystal violet on LDH/SDS follows Langmuir isotherm model and Pseudo-Second-Order kinetic model. Manuscript profile -
Open Access Article
4 - Investigation of temperature effect on composite membrane synthesis with the growth of nanoparticles of zeolitic imidazolate framework-8 via chemical vapor deposition
Hossein Hassannia Golsefid Omid Alizadeh Fatereh DorostiIn this research, polyetherimide (PEI) membranes were made via dry/wet phase inversion with non-solvent water. The effect of the temperature of the casting surface on membrane morphology and CO2 separation from CH4 were studied. Zeolitic imidazolate framework-8 crystals MoreIn this research, polyetherimide (PEI) membranes were made via dry/wet phase inversion with non-solvent water. The effect of the temperature of the casting surface on membrane morphology and CO2 separation from CH4 were studied. Zeolitic imidazolate framework-8 crystals (ZIF-8) were deposited on the PEI membrane with highest selectivity by the chemical vapor deposition (CVD) method to obtain the composite membranes (CM) via a reaction between a complex of zinc and 2-methyl imidazole. The effects of CVD temperature on the fabrication of ZIF-8, CM morphology, and CO2 separation from CH4 were surveyed. The results indicated that an increase in the film casting temperature enhanced CO2 permeation and created a finger-like membrane. Also, this temperature rising reduced the selective layer thickness and surface pores diameters of the PEI membranes. Physical and chemical characteristics of polymeric and the CM were determined using characterization methods. FESEM images and XRD pattern confirmed that ZIF-8 was grown sufficiently on the selective layer of PEI membranes at 50 °C. The fabricated CM, which their selective layer (ZIF-8) was made using atmospheric CVD method at 40, 50, and 70 °C, has higher selectivities of about 21 to 78 percent in comparison with PEI membrane. Selectivity and permeability of the CM fabricated at 100 °C were dramatically reduced. By increasing the temperature to 130 °C, the membrane structure was destructed. Manuscript profile -
Open Access Article
5 - Study on the biodegradation of SMR rubber to reduce the environmental wastes: the effects of curing system, reinforcement and oil
Somayyeh Mohammadian-GezazIn this work, the effects of the various parameters such as type of curing system, amount of filler, and type of oil were studied on the biodegradation of natural rubber (NR). The amount of degradation increased in the order of the efficient, semi-efficient and conventi MoreIn this work, the effects of the various parameters such as type of curing system, amount of filler, and type of oil were studied on the biodegradation of natural rubber (NR). The amount of degradation increased in the order of the efficient, semi-efficient and conventional curing system. NR degradation with the NR grade (based on the SMR types) was changed as SMR50 > SMR20 > SMR10 due to the higher impurity. By increasing the carbon black level, degradation decreased. The negative effect of the carbon black on the degradation was more obvious for the finer carbon black (N330) with respect to the coarser one (N550), at the same level. The lowest sole fraction was achieved for efficient curing system. Moreover, the sole fraction increased by NR type as SMR50 > SMR20 > SMR10. Unfilled NR had the higher degradation amount and the higher sole fraction. Manuscript profile -
Open Access Article
6 - Nanostructures prepared from natural ilmenite mineral for rapid degradation of furazolidone in heterogeneous Fenton process
Hamideh Haghighat Mehrangiz Fathinia Siavash FathiniaIn this study, for the first time, ilmenen-hematon nanostructures were prepared from natural ilmenite mineral by the exfoliation process in the presence of ultrasound wave for rapid degradation of furazolidone contaminant. The aim of the present study was to increase th MoreIn this study, for the first time, ilmenen-hematon nanostructures were prepared from natural ilmenite mineral by the exfoliation process in the presence of ultrasound wave for rapid degradation of furazolidone contaminant. The aim of the present study was to increase the reduction efficiency of iron (II) in the heterogeneous Fenton process by preparing ilmenn-Hematon nanostructures from its natural mineral. The effect of organic solvents such as dimethylformamide, N-methyl-2-pyrrolidine, isopropyl, and toluene to produce relevant nanostructures during the exfoliation process in the presence of ultrasound waves and as well as the effect of the obtained nanocatalyst in the heterogeneous Fenton process to degrade the pharmaceutical pollutant furazolidone, were investigated. The obtained results showed that the exfoliation process in the liquid phase by ultrasound wave in the presence of dimethylformamide solvent was successful and the band gap is reduced from 3.57 eV in the natural mineral ilmenite to 2.2 eV in the prepared nanocatalyst from it. The ability to absorb light and the degradation efficiency of furazolidone drug under visible light increased and after 60 minutes reached to a maximum of 95.5%. Optimal values of effective parameters for furazolidone degradation were modeled by experimental design using the response surface method (RSM) and Design-Expert7 software. The physical and chemical characteristics of the prepared nanocatalyst were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), dot mapping, Fourier transform infrared spectroscopy (FTIR), X-ray fluorescence spectroscopy (XRF), Brunauer–Emmett–Teller (BET), and Diffuse reflection spectroscopy (DRS) methods and the reproducibility of the prepared nanocatalyst was investigated during 6 cycles of the process. Also, the characteristics of the catalyst used in the reproducibility cycle were studied using XRD and FTIR techniques. Manuscript profile -
Open Access Article
7 - Low temperature ethanol vapor sensor based on H-CeO2/Fe nanocomposite:Ultra-sensitive, selective and repeatable performance
elnaz yousefian susan samadi Khadijeh Kalateh mohammad yousefi Ali ParsaIn this paper, hollow-CeO2/Fe (H-CeO2/Fe) nanocomposite was synthesized by hydrothermal assisted sol-gel method and the sensitivity of this gas sensor to ethanol, 2-propanol, and methanol was investigated. The structural properties and morphology of H-CeO2/Fe nanocompos MoreIn this paper, hollow-CeO2/Fe (H-CeO2/Fe) nanocomposite was synthesized by hydrothermal assisted sol-gel method and the sensitivity of this gas sensor to ethanol, 2-propanol, and methanol was investigated. The structural properties and morphology of H-CeO2/Fe nanocomposite were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), BET, and transmission electron microscopy (TEM). The synthesized sensor sensitivity to ethanol was higher than the other volatile organic compounds at 29 °C and relative humidity (RH) of 45%. The sensitivity, reproducibility, response, and recovery times as performance characteristics and relative standard deviation (RSD), limit of detection (LOD), and determination coefficient were also evaluated. The results showed that the H-CeO2/Fe sensor could be used to quantitative and qualitative analysis of ethanol. The response mechanism of the sensor to ethanol was also discussed. Manuscript profile -
Open Access Article
8 - Improving the Performance of N719 Based Dye-Sensitized Solar Cell by Application of Polypyrrole/Polyaniline Conductive Polymers as a Counter Electrode
Mahsa Mahdavinia Gholamreza Kiani Ayub Karimzad GhavidelThe aim of this research is the fabrication of a titanium dioxide nanostructure-based solar cell sensitized with N719 dye, and improving its efficiency with the application of a core-shell structure of polypyrrole/polyaniline as a counter electrode. The solar cells with MoreThe aim of this research is the fabrication of a titanium dioxide nanostructure-based solar cell sensitized with N719 dye, and improving its efficiency with the application of a core-shell structure of polypyrrole/polyaniline as a counter electrode. The solar cells with polymeric counter electrode were fabricated, in variable thicknesses by two spin coating and drop coating methods, and evaluated. In addition, the effect of nanowires and titanium dioxide nanoparticles concentration, present in photo-anode, was investigated on the performance of solar cell. The absorption amount of N719 dye was studied by spectrophotometer, and the maximum absorption was obtained at the wavelengths of 380 and 530 nm. The structural investigation of photo-anode and counter electrode by scanning electron microscope showed that the combination of nanoparticles and titanium dioxide nanowires with 1:9 ratio leads to a porous structure with a high surface-to-volume ratio that has a significant effect on the absorption of the dye and solar cell efficiency. The prepared solar cell by the drop coating method did not have appropriate performance. So, the focus of the research was directed towards the sample prepared by spin coating method. The solar cell sample with the counter electrode, containing polypyrrole/polyaniline, fabricated by spin coating method offers the open circuit voltage of 0.71 V, short circuit current of 2.58 mA, fill factor of 57.38, and efficiency of 1.05, which open circuit voltage and fill factor have been improved by 7.6 and 35 times compared to similar samples, respectively. Manuscript profile -
Open Access Article
9 - Determination of thermodynamic equilibrium conditions of ethane and propane gas hydrates using a direct and fast empirical method
Akbar Irandoukht hosein BrijanianIn this article, a direct and fast method was developed for determination of thermodynamic equilibrium conditions. The thermodynamic equilibrium pressure for ethane hydrate formation at 2, 4, 6, 8, 10, 12, and 14 °C and for propane hydrate formation at 2, 4 and 5 &d MoreIn this article, a direct and fast method was developed for determination of thermodynamic equilibrium conditions. The thermodynamic equilibrium pressure for ethane hydrate formation at 2, 4, 6, 8, 10, 12, and 14 °C and for propane hydrate formation at 2, 4 and 5 °C were experimentally determined. Comparison of the obtained data for ethane hydrate pressure to that of Deaton-Frost and also to those predicted by AQUAlibrium software showed the average absolute deviation percent of 4.56, 4.79, and 3.27, respectively. In addition, comparison of the obtained data for propane hydrae pressure to that of Deaton-Frost and HWU software, showed the average absolute deviation percent of 10.17, and 13.31, respectively. Manuscript profile -
Open Access Article
10 - Investigation of simultaneous removal of Basic Orange 2 dye and Ni(II) from aqueous solutions by modified nanoclay in continuous washing system using response surface methodology (RSM)
Armin Geroeeyan Ali Niazi Elaheh KonozIn the present study, the removal of Basic Orange 2 (BO2) dye and Ni(II) from aqueous solutions was studied using modified montmorillonite nanoclay (MMT). To characterize the adsorbent, FESEM and EDX-MAP analyses were performed. The process of the removal of pollutants MoreIn the present study, the removal of Basic Orange 2 (BO2) dye and Ni(II) from aqueous solutions was studied using modified montmorillonite nanoclay (MMT). To characterize the adsorbent, FESEM and EDX-MAP analyses were performed. The process of the removal of pollutants was investigated through the designing and fabrication of the continuous washing system and the effect of important variables influencing the process such as concentration of dye and Ni(II), pH, length of column and the number of washing cycles was evaluated. Response surface methodology (RSM) using central composite design (CCD) has been applied to study the influence of experimental factors on the simultaneous removal of BO2 dye and Ni(II) in continuous system and the interaction of the variables were scrutinized through response surface curves. According to RSM results and optimization of simultaneous removal of BO2 dye and Ni(II) using desirability function, the optimal values for the five variables of dye concentration, Ni(II) concentration, pH, length of column, and number of washing cycles were found 12.07 mg L-1, of 12.97 mg L-1, 8.18, 12.97 cm and 2, respectively. The results of the removal of BO2 dye and Ni(II) in continuous washing system using modified montmorillonite nanoclay showed that this method can be efficient for the adsorption of pollutants from aqueous solutions. Manuscript profile -
Open Access Article
11 - Investigation on correlation between the content of palmitic acid methyl ester obtained by transesterification of natural rubber’s extracted lipids and cure characteristics of rubber compounds using gas chromatography – mass spectroscopy
Fereshteh Eildari Mercedeh Malekzadeh Mandana Saber Tehrani Fereshteh MotieeIn this research work, the correlations between the curing properties of natural rubber based compounds were investigated with the content of palmitic acid methyl ester obtained by transesterification of natural rubber’s extracted lipids. For this purpose, at the MoreIn this research work, the correlations between the curing properties of natural rubber based compounds were investigated with the content of palmitic acid methyl ester obtained by transesterification of natural rubber’s extracted lipids. For this purpose, at the first step the lipids in natural rubber were extracted and methyl esters derivatives were prepared. At the second step the obtained palmitic acid methyl esters from different natural rubbers were identified and quantified by gas chromatography-mass spectrometry. Finally the correlations between the amount of palmitic acid methyl ester and curing properties of rubber compounds were investigated and linear models were obtained. These models were used for prediction of cure properties in a case study. The results showed that scorch time, optimum cure time and cure rate index can be predicted by less than 6% error and torque difference can be estimated by lower than 13% error. This new approach can be used to predict the cure properties of the compound before compounding. Manuscript profile -
Open Access Article
12 - Investigating the effect of zeolite catalyst in the co-pyrolysis of low density polyethylene and poplar wood
Sepideh Behnam Mortaza GholizadehIn this study, the effect of zeolite on the process of mixing poplar wood and low density polyethylene (LDPE) was investigated. For this purpose, in a laboratory-sized reactor, 15 g of this mixture was loaded and pyrolysis of the mixture was performed at 500 °C, atm MoreIn this study, the effect of zeolite on the process of mixing poplar wood and low density polyethylene (LDPE) was investigated. For this purpose, in a laboratory-sized reactor, 15 g of this mixture was loaded and pyrolysis of the mixture was performed at 500 °C, atmospheric pressure, and in the atmosphere of nitrogen gas. Addition of A4 zeolite catalyst to the pyrolysis of poplar wood and LDPE increased the amount of tar. The produced tar had two groups of aliphatic and aromatic compounds. The catalyst also increased the amount of aromatic substances in the tar and improved the quality of the tar by deoxygenation. According to the results of SEM analysis, it was found that the structure of the solutions produced by thermal and catalytic pyrolysis was similar to the structure of poplar wood. However, the catalytic products had more porosity. The results of FTIR analysis showed that the addition of catalyst caused a slight deoxygenation of wax surface obtained from catalytic pyrolysis and also reduced the amount of wax produced. These results showed that A4 zeolite catalyst tended to deoxygenate the surface of the products. According to the XRD patterns and elemental analysis of the catalyst, it was determined that a very small amount of coke was formed on the catalyst after the reaction. Manuscript profile
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