mohammadjavad vaezi

In this study, carbon adsorbents were synthesized from tire waste using a dry carbonization process to remove inorganic arsenic ions from aqueous environments. The influence of various carbonization process parameters such as holding time (0.5 to 4 hours), process temperature (400 to 850°C), reactor pressure (-0.6 to 10 bar), and particle size on the mass yield and adsorption capacity of the adsorbents was investigated. Subsequently, the porosity and functional groups of the adsorbents were characterized using FTIR, BET-BJH, and XRD techniques. The results indicated that all variables positively impacted the achievement of optimal conditions. The highest adsorption capacity for arsenic ion removal was obtained under the optimal conditions of a 2-hour holding time, a temperature of 700°C, a pressure of -0.3 bar, and a particle size of 3 mm. The findings showed that the char derived from tire waste could serve as a relatively cost-effective adsorbent for the remediation of arsenic-contaminated water.

In this study, the DD3R zeolite powder and membrane were synthesized via a secondary growth method. The XRD and SEM analyses show the successful synthesis of the DD3R zeolite powder and membrane. The calcination of the membrane was carried out at 500 ◦C with a heating rate of 0.2 ◦C/ min. The N2 gas permeation test was carried out at different temperature steps simultaneously with increasing the temperature. The results show that after 425 ◦C, N2 permeation increases by about 100 times, which indicates thermal shock and creating non-zeolite pores with size in nanometric range in the membrane. The calcination of another membrane at 500 ◦C with a heating rate of 0.1 ◦C/ min also was resulted in defects of the membrane. Finally, the calcination of the DD3R membrane at 425 ◦C with a heating rate of 0.2 ◦C/min prevented thermal shock, and then the defects were minimized in the membrane. So that, the perm-selectivity of CO2/CH4 and N2/CH4 were measured 10-11 and 4-5, respectively.

One of the events that led to the creation of Ottoman sect was the murder of the third Khalif. Considering the different accounts of the Uthman’s murder and the role of Imam Ali, the present study attempts to find out the root of these discrepancies. The significance of this is that analyzing the context, origin, and consequences of an event determines the background of every historian’s account of the event. The findings of this study revealed that Ibn Sa’d in his account has depicted an innocent, saint-like image of the Khalif due to his zealotry. Al-Baladhuri expresses his sympathy for the Shia while legitimizing the rebellion. Considering the descriptions of the Khalif’s incompetence and Imam’s neutrality, one can draw onto Ya’qubi’s moderate Shi’ism tendency. Although he is not a Shia, Al-Tabari considers Imam as a sincere protector of the Khalif’s life. Finally, Al-Masudi’s account indicates his Shia tendencies that are displayed through an emphasis on the democratic nature of the rebellion and Imam’s efforts to save the Khalif’s life.

An investigation of the narratives of the renowned historians (Ibn Sa''d in Tabaqat al-Kubra¡ Al-Baladhuri in Genealogies of the Nobles¡ Ya''qubi in Tarikh al-Yaqubi¡ Al-Tabari in History of the Prophets and Kings and Al-Masudi in The Meadows of Gold) reveals that they were selective in reporting about the lives of Imams and they tried to have some influences on the minds of the audience. The virtues of the Imams are not exceptions. This article tries to examine the reflection and the composition of the virtues of Imams as indicated in these sources. Moreover¡ it tries to investigate the special approach of each individual source in inducing a particular mentality in the minds of people. The common point in all the resources is mentioning about the virtues of the very first Imams and inattending to other Imams (AS). Apparently virtue has a close hidden relationship with the time affinity with the Messenger of Allah and as the distance increases¡ the virtues of Imams (AS) become more invisible. Each of the five sources adopts a different approach in reflecting the virtues of Imams.

The goals of this work are to synthesize and evaluate the potential of hydroxy sodalite membrane in the separation of helium from natural gas. Sodalite membrane was synthesized via direct hydrothermal method (conventional heating) on tubular alumina support. It was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and single gas permeation using helium and N2. After drying of the membrane, permeances of single gases were found to be of the order Helium > CH4 > N2 > CO2 at low temperatures and the membrane was impermeable to N2, CO2 and CH4 at high temperatures (>85 °C). In the investigated range of temperature 35-180 °C, membrane performance tended to high selectivity. The maximum separation factors (helium/N2 ~ 8.8, helium/CO2 ~ 16.5 and helium/CH4 ~ 5) with acceptable permeance were observed at 85 °C.

In this study the catalytic dehydrogenation of ethylbenzene to styrene was investigated in a simulated tubular sodalite membrane reactor. The high quality microporous sodalite membrane was synthesized by direct hydrothermal method and characterized by single gas permeation measurements. The performance of the prepared membrane showed high potential for application in a dehydrogenation membrane reactor (MR). The performance of the MR was evaluated using a pseudo-homogeneous model of the fixed bed that was developed in this purpose. The obtained results were evaluated in comparison with corresponding predictions for a plug flow reactor (PFR) operated at the same conditions. The modeling results confirmed the high performance of a MR over a conventional PFR. Ethylbenzene conversion and styrene yield increased about 3.45% and 8.99% respectively which is attributed to the effect of hydrogen removal from reaction side. The results demonstrate that the styrene yield in the MR is predicted to be more effective than that of in the conventional PFR.

The main goal of this work was to synthesize and evaluate the effect of dehydration temperature on the potential application of hydroxy sodalite zeolite membrane. Hydroxy sodalite zeolite membranes were synthesized via direct hydrothermal method onto a tubular alumina support without seeding in a hot air oven. The synthesized membranes were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Permeation tests of H2 and CO2 were carried out in order to investige the applied dehydration temperature effect on the performance of the synthesized membranes. The performance of the synthesized membrane dehydrated at 100 ºC tended to high selectivity compared to that of the rest samples and the maximum separation factor (~21) was achieved with acceptable permeances about 3.810-8 and 1.8*10-9 mol.m-2.Pa-1.s-1 for H2 and CO2, respectively. The low selectivities observed for two other synthesized membranes (dehydrated at 150 and 200 ºC), indicating the formation of defects during the dehydration of these membranes at high temperatures.