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Showing 2 results for Rashidzadeh


Volume 5, Issue 3 (Fall 2021)
Abstract

Research subject: Hydrodesulfurization is one of the effective methods to remove sulfur compounds from oil fractions and improve fuel quality. One of the major challenges in this process is to find the proper catalyst support that performs best. In the meantime, modified supports with zeolite have allocated a lot of attention due to their strong acidic sites, specific surface area and high hydrothermal and chemical stability; But the acidity and volume of zeolite mesopores need to be corrected.
Research approach: In this study, first, hierarchical Y zeolite was prepared using post-synthesis (Dealumination) and using ammonium form of zeolite and NH4F solution (0.75 M) at 90˚C for 3h under reflux conditions. Physicochemical properties of zeolite were investigated by BET, FESEM, FTIR, AAS and XRD analyzes. Modified zeolites were used in the support synthesis of the HDS process catalyst. The sulfidation and performance evaluation of the prepared catalysts were carried out in the fixed-bed microreactor were performed with diesel cutting feed from the Isomax unit of the target refinery.
Main results: The results show that the volume of mesopores, specific surface area and SiO2/Al2O3 ratio in hierarchical zeolites has increased 0.073 cm3 g-1, 783.36 m2 g-1 and 5.2, respectively (initial values are 0.032 cm3 g-1, 567.18 m2 g-1 and 4.5). The results of zeolite analysis show the preservation of the structure and crystallinity during the zeolite modification process. The effect of zeolite modification, especially the Si/Al ratio variations, mesopores and specific surface area, was investigated on the activity of NiMo/Zeolite+Al2O3 catalysts. Increasing the acidity and improving the physicochemical properties of the modified zeolites has increased the catalyst performance in the process of diesel hydrodesulfurization (Conversion= 90%). Improving the activity of catalysts can be attributed to the positive effect of zeolites on the dispersion of the metallic site, surface area, acidity, optimal size of pores and volume of catalyst mesopores.

Volume 18, Issue 114 (August 2021)
Abstract

Optimization of extraction of bioactive compounds from seedless barberry fruit using pulsed electric field pretreatment
Abstract
 
In this research, in order to optimize the extraction process of Ethanolic extract of barberry fruit, the increase and optimization of the conditions for the extraction of anthocyanin's and bioactive compounds by means of intermittent electric field pre-treatment from three levels of electric field intensity (0.5, 1.75 and 3 kV / cm) and 3 levels of number of pulses (15, 30 and 45); then with ethanol solvent was used to extract their extracts and the amount of flavonoids, total anthocyanin, DPPH, total phenolic compounds, iron regeneration capacity, vitamin C and acidity compared to control (no treatment)  Was studied. The results showed that the total phenol content of the extract decreased by increasing the number of pulses and reducing the intensity of the pulsed electric field applied to the sample. The increase in the electric field strength and the number of pulses initially increased the flavonoid content, DPPH and iron ion recovery capacity, but with the increase of these variables, these three parameters decreased. Also, with increasing of these parameters, the anthocyanin level and vitamin C content increased. The acidity of the sample was reduced and then increased by increasing the electric field strength and applied pulse number. Regarding the results of the process optimization, it can be concluded that the electrical field intensity of 2.003 kV / cm and applying 29 pulses can increases the antioxidant properties of the produced product compared with the control sample.

 

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