Production of eco friendly DME fuel over sonochemically synthesized UiO66 catalyst.

The ultrasound-assisted preparation of UiO-66 was carried out at T = 80-220 °C, and the catalytic performances were evaluated in methanol conversion. Also, physicochemical properties were assessed by XRD, SEM, PSD, FTIR, N2 adsorption-desorption, TG-DTG, and NH3-TPD analysis. The characterization proved that increasing the synthesis temperature positively affected the crystallinity, specific surface area, thermal stability, and acidity of the catalysts. Besides, the catalysts' performance was investigated in the methanol conversion reaction (T = 350-450 °C, P = 1 atm, and WHSV = 5 h-1), leading to the DME (Dimethyl Ether) production. Rising reaction temperature increased the methanol conversion and DME yield. The synthesized sample at 220 °C had the best properties and performance with conversion and yield of about 38% and 51%, respectively. The stability test for the UiO-66-220 (University of Oslo 66) catalyst was performed at 450 °C for 12 h, and the activity remained stable for about 5 h. Furthermore, the used catalyst was characterized via XRD and TG analysis.

Synthesis and application of recyclable magnetic cellulose nanocrystals for effective demulsification of water in crude oil emulsions.

The development of eco-friendly, efficient, and economical demulsifiers for the demulsification of water in crude oil emulsion is one of the important issues in the petroleum industry. Demulsifiers with suitable performance in several demulsification methods are good choices for effective and economical demulsification. In this study, recyclable magnetic cellulose nanocrystals have been synthesized from cotton by a simple method and used in the demulsification of water in crude oil emulsions. Chemical and magnetic demulsification by magnetic cellulose nanocrystals has been investigated. In addition, the effects of time, temperature, and demulsifier concentration on the demulsification efficiency have been evaluated. According to the results, this demulsifier can be used as an effective demulsifier for both chemical and magnetic demulsification and displayed a demulsification efficiency of 100 % at 50 °C without a magnet and 90 % at 20 °C with a magnet. The chemical demulsification efficiency of Fe3O4 nanoparticles was investigated and it showed lower DE compared to magnetic cellulose nanocrystals. The recyclability tests of the demulsifier indicated that magnetic cellulose nanocrystals can be used up to 4 times. Finally, the demulsification mechanism and interfacial tension measurements revealed that this demulsifier reduced the interfacial tension between water and crude oil and increased the water droplet sizes.

Molecular dynamics simulation study of doxorubicin adsorption on functionalized carbon nanotubes with folic acid and tryptophan.

In this work, molecular dynamics (MD) simulation is used to study the adsorption of the anticancer drug, doxorubicin (DOX), on the wall or surface of pristine and functionalized carbon nanotubes (FCNTs) in an aqueous solution. Initially, the CNTs were functionalized by tryptophan (Trp) and folic acid (FA), and then the DOX molecules were added to the system. The simulation results showed that the drug molecules can intensely interact with the FCNTs at physiological pH. Furthermore, it was found that as a result of functionalization, the solubility of FCNTs in an aqueous solution increases significantly. The effect of pH variation on drug release from both pristine and FCNTs was also investigated. The obtained results indicated that in acidic environments due to protonation of functional groups (Trp) and as a result of repulsive interaction between the DOX molecule and functional groups, the release of DOX molecules from FCNT's surface is facilitated. The drug release is also strongly dependent on the pH and protonated state of DOX and FCNT.

Molecular Dynamics Assessment of Doxorubicin Adsorption on Surface-Modified Boron Nitride Nanotubes (BNNTs).

Loading therapeutic agents on nanocarriers in order to protect them during drug delivery and exclusively targeting damaged tissues has gained substantial significance in biology realms in the past decade. Boron nitride nanotubes have given a new lease on designing nano delivery systems by virtue of their unique properties. The studies are still ongoing to thoroughly identify their chemical characteristics. In this study, we probed into the efficacy of boron nitride nanotubes and the impact of their surface modification by hydroxyl and amine functional groups in interaction with an anticancer drug model, i.e., doxorubicin. Defining the altered electronic properties of the nanotubes as well as the distribution of partial charges were carried out through density functional theory calculations, following the simulation of the drug loading process via molecular dynamics algorithms. The primary outcomes are inferred from systematical energies, van der Waals and electrostatic interactions, radial distribution functions, the number of hydrogen bonds, mean square displacement, diffusion coefficients, and binding free energies. Negative values of van der Waals energies imply a rapid, exothermic adsorption process whereby the contribution of these driving forces is more dominant than electrostatic ones. Ultimately, the values of overall diffusion coefficients of drugs and binding free energies, performed by the MM/PBSA approach, corroborate that the hydroxyl and amine-functionalized nanotubes reinforce the binding strength of the complexes to an approximate extent.

Catalytic Longevity of Hierarchical SAPO-34/AlMCM-41 Nanocomposite Molecular Sieve In Methanol-to-Olefins Process.

INTRODUCTION: SAPO-34/AlMCM-41, as a hierarchical nanocomposite molecular sieve was prepared by sequential hydrothermal and dry-gel methods studied for catalytic conversion of methanol to light olefins. Pure AlMCM-41, SAPO-34, and their physical mixture were also produced and catalytically compared. Physicochemical properties of materials were mainly investigated using XRD, N2 isothermal adsorption-desorption, FESEM, FT-IR, NH3-TPD, and TG/DTG/DTA techniques. METHODS: Micro-meso hierarchy of prepared composite was demonstrated by XRD and BET analyses. Catalytic performance of materials illustrated that the methanol conversion of the prepared composite was about 98% for 120 min, showing a higher activity than the other catalysts. The initial reaction selectivity to light olefins of the composite was also comparable with those for the other catalysts. Furthermore, the results revealed that SAPO-34/AlMCM-41 preparation decreased the concentration and strength of active acid sites of the catalyst which could beneficially affect the deposition of heavy molecular products on the catalyst. However, as observed, the prepared composite was deactivated in olefins production faster than pure SAPO-34. RESULTS: The small mean pore diameter of composite could be mainly responsible for its pore blockage and higher deactivation rate. Meanwhile, since the SAPO-34 prepared by dry-gel method had inherently high mesoporosity, the AlMCM-41 introduction did not promote the molecular diffusion in the composite structure. CONCLUSION: The coke content was found 15.5% for deactivated composite smaller than that for the SAPO- 34 catalyst which could be due to the pore blockage and deactivation of the composite in a shorter period.

Life Time Improvement of Hierarchically Structured SAPO-34 Nanocatalyst in MTO Reaction via Applying Clinoptilolite: Investigating of Composite Design via RSM.

AIM AND OBJECTIVE: The research focuses on recent progress in the production of light olefins. Hence, as the common catalyst of the reaction (SAPO-34) deactivates quickly because of coke formation, we reorganized the mechanism combining SAPO-34 with a natural zeolite in order to delay the deactivation time. MATERIALS AND METHODS: The synthesis of nanocomposite catalyst was conducted hydrothermally using experimental design. Firstly, Clinoptilolite was modified using nitric acid in order to achieve nano-scaled material. Then, the initial gel of the SAPO-34 was prepared using DEA, aluminum isopropoxide, phosphoric acid and TEOS as the organic template, sources of Aluminum, Phosphor, and Silicate, respectively. Finally, the modified zeolite was combined with SAPO-34's gel. RESULTS: 20 different catalysts due to D-Optimal design were synthesized and the nanocomposite with 50 weight percent of SAPO-34, 4 hours Crystallization and early Clinoptilolite precipitation showed the highest relative crystallinity, partly high BET surface area and hierarchical structure. CONCLUSION: Different analyses illustrated the existence of both components. The most important property alteration of nanocomposite was the increment of pore mean diameters and reduction in pore volumes in comparison with free SAPO-34. Due to the low price of Clinoptilolite, the new catalyst renders the process as economical. Using this composite, according to the formation of multi-sized pores located hierarchically on the surface of the catalyst and increased surface area, significant amounts of Ethylene and Propylene, in comparison with free SAPO-34, were produced, as well as the deactivation time was improved.

Synthesis, characterization, and CO2 adsorption properties of metal organic framework Fe-BDC.

The iron-containing Metal-Organic Frameworks (MOFs) have attracted a great deal of attention in the areas of gas separation, catalytic conversion, and drug delivery, due to their high surface area and activity, as well as the non-toxicity of iron. In this study, Fe-based MOFs using BDC ligands, MIL-101(Fe), MIL-53(Fe) and Amino-MIL-101(Fe) are synthesized by a solvothermal method and characterized by conventional methods such as BET, SEM, and TGA. Afterwards, the synthesized MOFs are investigated from the point of view of the adsorbing capability of carbon dioxide at different pressures and temperatures, and also their resistance to water and solvent. The results showed that Amino-MIL-101(Fe) achieved more CO2 adsorption than MIL-101(Fe) and MIL-53(Fe), equal to 13 mmol g-1 at 4 MP. Although MIL-53(Fe) has the best temperature resistance, around 350 °C, Amino-MIL-101(Fe) is more stable against water and ethanol and its surface area is increased from 670 to 915 m2 g-1 after washing with ethanol. The adsorption study reveals that CO2 is adsorbed not only by a physical adsorption mechanism, but also by chemisorption of acidic carbon dioxide by basic NH2 agent in the structure of Amino-MIL-101(Fe).

Different view of solvent effect on the synthesis methods of zeolitic imidazolate framework-8 to tuning the crystal structure and properties.

One of the important aims in the synthesis of zeolite imidazolate framework-8 is to prepare crystals with predictable structures and valuable properties. It is observed that the properties of ZIF-8 have been directly or indirectly determined by various synthetic factors. Among many synthetic factors, solvents and synthesis methods are unavoidable parameters that control the overall structure of ZIF-8. This article presents a deep understanding of how solvents play their role in the crystallization and structure and therefore the properties of ZIF-8 by considering the polarity, viscosity, interfacial tension and molecular structure and comparing the behaviour of each solvent in every synthesis method. Also, to clearly realize their effect on the formation and final properties of ZIF-8, the crystallization process and mass transfer are discussed.

Performance analysis of ultrasound-assisted synthesized nano-hierarchical SAPO-34 catalyst in the methanol-to-lights-olefins process via artificial intelligence methods.

The present study has focused on performance analysis of ultrasound-assisted synthesized nano-hierarchical silico-alumino-phosphate-34 (SAPO-34) catalyst during methanol-to-light-olefins (MTO) process. A classical method, i.e., multiple linear regression (MLR) and two intelligent methods, i.e., genetic programming (GP) and artificial neural networks (ANN) were used for modeling of the performance of nano-hierarchical SAPO-34 catalyst. We studied the influence of basic parameters for the sonochemical synthesis of nano-hierarchical SAPO-34 catalyst such as crystallization time, ultrasonic irradiation time, ultrasonic intensity, amount of organic template (diethylamine (DEA) and carbon nanotube (CNT)) on its performance (methanol conversion and light olefins selectivity) in MTO process. The results revealed that the models achieved using the GP method had the highest accuracy for training and test data. Therefore, GP models were used in the following to predict the effect of main parameters for the sonochemical synthesis of nano-hierarchical SAPO-34 catalyst. Finally, an optimal catalyst with the highest yield into light olefins was predicted using the genetic optimization algorithm. The genetic models were employed as an evaluation function in the genetic algorithm (GA). A good agreement between the outputs of GP models for the optimal catalyst and experimental results were obtained. The optimal ultrasound-assisted synthesized nano-hierarchical SAPO-34 was accompanied by light olefins selectivity of 77% and methanol conversion of 94% from the onset of the process after 9 h.

Presenting a new kinetic model for methanol to light olefins reactions over a hierarchical SAPO-34 catalyst using the Langmuir-Hinshelwood-Hougen-Watson mechanism.

In this study, a new kinetic model for methanol to light olefins (MTO) reactions over a hierarchical SAPO-34 catalyst using the Langmuir-Hinshelwood-Hougen-Watson (LHHW) mechanism was presented and the kinetic parameters was obtained using a genetic algorithm (GA) and genetic programming (GP). Several kinetic models for the MTO reactions have been presented. However, due to the complexity of the reactions, most reactions are considered lumped and elementary, which cannot be deemed a completely accurate kinetic model of the process. Therefore, in this study, the LHHW mechanism is presented as kinetic models of MTO reactions. Because of the non-linearity of the kinetic models and existence of many local optimal points, evolutionary algorithms (GA and GP) are used in this study to estimate the kinetic parameters in the rate equations. Via the simultaneous connection of the code related to modelling the reactor and the GA and GP codes in the MATLAB R2013a software, optimization of the kinetic models parameters was performed such that the least difference between the results from the kinetic models and experiential results was obtained and the best kinetic parameters of MTO process reactions were achieved. A comparison of the results from the model with experiential results showed that the present model possesses good accuracy.

Heavy Metal Ions Uptake by AlPO-5 and SAPO-5 Nanoparticles: An Experimental and Modeling Study.

Synthesis of AlPO-5 and SAPO-5 nanoparticles was followed by applying hydrothermal method to use them as adsorbents in the removal of Fe3+, Pb2+, and Cd2+ions.The synthesized products were characterized using powder X-ray diffraction, scanning electron microscope (SEM), FTIR and BET analysis. The adsorption isotherms and kinetics including Langmuir, Freundlich, pseudo-first order, pseudo-second order and intraparticle diffusion models have been employed. The experimental adsorption equilibrium and kinetic data nearly followed the Langmuir isotherm and pseudo-second order kinetic model, respectively. It was found that the existence of the bridging hydroxyl group in the SAPO-5 structure causes chemisorption of Fe3+, Pb2+, and Cd2+ions on SAPO-5 which have greatly improved the performance of this adsorbent against its low external surface area. Using AlPO-5 and SAPO-5 as novel adsorbents in heavy metal adsorption for the first time indicated the great potential of these adsorbents in removal of heavy metal ions from water.

An investigation of the crystallization kinetics of zeotype SAPO-34 crystals synthesized by hydrothermal and sonochemical methods.

The kinetics study of SAPO-34 crystallization from a gel containing morpholine as a structure directing agent (SDA) was investigated by means of X-ray diffraction (XRD) patterns in order to determine the kinetics parameters, i.e. induction times, rate constants, frequency factors, and activation energies for the induction and growth stages. The kinetics data of growth period were determined by using the Avrami-Erofeev nucleation growth model. SAPO-34 molecular sieves were synthesized by using both sonochemical-assisted hydrothermal and conventional hydrothermal heating at temperatures of 180, 200, and 220 °C to elucidate the influence of crystallization method on the crystallization kinetics of SAPO-34. The activation energy values indicated that the crystal growth mechanism was enhanced for samples synthesized sonochemically, whereas the induction energy was not greatly affected by using sonication process. Also, the kinetic compensation effect (KCE) was considered in order to obtain the isokinetic temperature.

Synthesis of hierarchal SAPO-34 nano catalyst with dry gel conversion method in the presence of carbon nanotubes as a hard template.

In this study, the silicoaluminophosphate (SAPO) particles were synthesized based on dry gel conversion method using diethyl amine (DEA) as an organic structure directing agent (SDA). Transport pores were introduced into the crystalline structure of the catalyst using carbon nanotubes (CNT) as a hard template. The significance of molar ratio of CNT in the starting gel and the other synthesis parameters such as crystallization time, gel drying temperature and water content added in the crystallization stage, on crystallinity of SAPO-34, crystal phase, particle size and morphology were studied. The products were characterized by XRD, SEM, TEM, BET and EDX. D-optimal experimental design with four numeric factors including gel drying temperature, crystallization time, water/dry gel mass ratio and mole of CNT in the precursor gel each at three levels was implemented to optimize the experimental parameters by analysis of variance (ANOVA). The Fischer test results showed that, all the parameters have significant effect on the crystallinity of the synthesized samples.