فهرست مطالب seyed nezameddin ashrafizadeh

The use of copper metal and its alloys is increasing day by day due to the unique properties of this metal in the electronics, steel alloys and other applications. One of these methods is the use of microfluidic systems. The use of microfluidic systems in continuous separation processes has received much attention in the last two decades. In this study, first the microfluidic system made of glass was made by laser cutting method and then the solvent extraction of copper metal ion was performed by using the microfluidic technique and using PHOSPHORIC ACID 2-ETHYLHEXYL ESTER (MDEHPA) cation extractor in the Y-Y microchannel and the parameters that affecting it have also been investigated, the experiment was designed by using the response level method and the effect of single and simultaneous operational parameters including volume concentration of the extractor, pH of the aqueous phase and residence ion extraction was investigated. In this regard, the amount of extractor concentration 11% (vol/vol), pH equal to 5 and residence time equal to 20 seconds were obtained as optimal operating conditions. In optimal operating conditions, the amount of copper extraction from the aqueous phase was 88.45%. Also the ratio of two-phase aqueous and organic discharges was changed, which according to the results obtained in the Qorg⁄Qaq ratio equal to 2⁄1 the copper ion extraction efficiency increased from 88.45% to 90.54%. The total volumetric mass transfer coefficients (KLa) were also calculated under different conditions to evaluate the mass transfer performance in the microfluidic system. The results showed that KLa values decreased nonlinearly with increasing residence time. The highest KLa values were observed between (0.13-0.78 1⁄s) during the residence time equal 20 second, which is much higher than the KLa values in batch extraction, which indicates better mass transfer performance of the microfluidic system.

Nitrate is one of the most important water pollutions that affect human life. Electrocoagulation is a common method for removing nitrate from water. In this research, using Design expert software and the CCD method, 48 experiments were performed in different parameters, including initial nitrate concentration in the range of 10-30 mg/L, 5-11 for pH, 2-10 cm for electrode distance, 5-30 V for voltage, and 20-120 min for process time. The electrodes were made of aluminum (anode) and iron (cathode), and the reactor volume was 2 liters. The highest nitrate removal was obtained in Ci = 16 mg/L, PH = 9.3, ED = 4 Cm, V = 23 v, ET = 90 min, reached . Then, the effect of sodium chloride salt, mechanical stirrer, and the number of electrodes was investigated in optimal points.

Solvent extraction of samarium from aqueous solutions by two different types of extractants, namely D2EHPA and PC88A, in kerosene was investigated. Through identification of speciation diagrams, the chemically stable complexes of samarium in different acidic solutions (H2SO4, HCl and HNO3) were first investigated. Regarding the various types of samarium species in sulfate medium in comparison with other acidic environments, H2SO4 and HNO3 media were chosen to examine the extraction behavior of samarium complexes. Thermodynamic parameters of samarium extraction reactions by D2EHPA and PC88A from aqueous solutions of HNO3 and H2SO4 were calculated as ∆G∘ (D2EHPA-HNO3),  , ∆G∘ (D2EHPA-H2SO4) , ∆G∘ (PC88A-HNO3), ∆G∘ (PC88A-H2SO4)  equal to -5.58, 3.40, 6.70 and 14.26, and respective ΔHº values equal to -9.38, -2.75, 4.01 and 16.95 kJ/mol, respectively. According to the results, D2EHPA seemed to be a more efficient extractant than PC88A and nitric aqueous solution was a better media than the sulfuric one. The synergistic effect of binary extractants revealed that synergistic factors were 2.94 and 5.74 in sulfuric and nitric solutions, respectively, for a D2EHPA:PC88A ratio of 2:3. The compositions of extracted complexes by D2EHPA and PC88A in sulfuric and nitric solutions were SmH3A6 and SmH3B6, respectively. Thermodynamic parameters of extraction reactions were calculated to be Ke equal to 9.513, 0.254, 0.067, and 0.003 and ∆S∘ (D2EHPA-HNO3),  , ∆S∘ (D2EHPA-H2SO4) , ∆S∘ (PC88A-HNO3), ∆S∘ (PC88A-H2SO4) equal to -12.75, -20.64, -9.03, and 9.03 (J mol-1), respectively.

Separation of samarium and lutetium was investigated through solvent extraction from their mixed aqueous species using commercial extractants of D2EHPA and PC88A. The Response Surface Method (RSM) was utilized to design the solvent extraction experiments. In which, a Central Composite Design (CCD) was applied to set the optimum conditions for highest separation factors between Sm and Lu. Design of Experiments (DOE) was conducted by making use of four operating variables, namely initial pH of the aqueous solutions (A: 0.2–2.6), extractant concentration (B: 0.01-0.09 molar), mole fraction of D2EHPA in the extractant mixture (C: 0 - 0.8) and a type of acidic solution (D: sulfuric and nitric acid) at three levels. The results indicated that the initial pH was the most paramount variable in solvent extraction of samarium and lutetium, while in the case of lutetium, the molar fraction of D2EHPA in the mixed extractants was non-influential. The statistical model predictions were confirmed by experiments for both samarium and lutetium extraction with high validity parameter of 97 and 98%, respectively. The optimum conditions for samarium and lutetium separation were identified as: A=0.8, B= 0.05, C= 0.2 and D= sulfuric acid. According to the findings of the model, the desirability value at the optimum conditions was evaluated as about 0.93, in which 71% of lutetium was extracted while the amount of extracted samarium was only less than 1%.

Following the previous part that emphasized on the necessity of accommodating biology in the curriculum of chemical engineering, here we are going to discuss about education conditions, curriculums, pioneer universities, science production procedure and industrial position of Chemical and Biological Engineering. Meanwhile, the increasing tendency of chemical engineering departments in the United States to modify their names and getting involved with biology, has been highlighted. Furthermore a report of progressive procedure of relevant articles and conferences has been provided (indicating the applicable aspects of “biology and chemical engineering”). In addition, it is mentioned that huge amounts of investments have been made on the projects related to this field. This paper also reveals that despite the aforementioned facts, Iranian chemical engineering curriculum, except a small portion of chemical engineering community who wish to expand their own personal knowledge, is almost alien to biology. A re-consideration in the conventional curriculum of Iranian chemical engineering, in order to accommodate “biology” and its branches, has been recommended to overcome the named challenges.

Development of biology has created new fields, such as Biotechnology and Biomedical Engineering. The advances in the mentioned fields, which are all interdisciplinary, depend on the activities of chemical engineers who are familiar with science biology. The necessity of chemical engineer`s activities in relevant areas with biology and inevitable use of biological means in confrontation of chemical engineering with environmental, economical and industrial challenges, proved that in the current century the sole familiarity with chemistry is not responsive to the needs of chemical engineering. However, the science of biology must be also considered as an important element of the modern chemical engineering along with the chemistry. In contrast to the developed countries, which have applied this important item in their educational systems, and even changed the title of this field to "chemical and biological engineering", Iranian chemical engineering has not profited biology in confrontation with new challenges; except a few who have educated in this area at graduate levels. This research is conducted with the aim of awareness regarding the necessity of transition from "chemical engineering" to "chemical and biological engineering" where the graduates are chemical engineers being familiar with biology. In this regard, the general educational program of "chemical and biological engineering" field has been reviewed and it has been recommended to update the curriculum of chemical engineering, or to establish such fields, in order to provide the requirements for the new engineering areas and also more efficient confrontation with new challenges.

Synergy of science and technology during the past decades, has discovered some new aspects and technologies. One of the very novel aspects is Microfluidics; the science and technology of controlling the motion of tiny volumes of fluids. It has been predicted that by development of this new field of science and technology, a revolution similar to what has happened by introduction of microchips to computer industry, will take place in chemical engineering. Microfluidics, its applications, challenges, and relation to chemical engineering, are investigated in this paper. Furthermore, a report about the researches and studies conducted in chemical engineering faculties on Microfluidics is presented. In developed countries, chemical engineering faculties have acknowledged the importance of Microfluidics, by establishing some laboratories and research centers, and in some cases, have held some courses in this field. In contrast, Iranian faculty members and researchers in chemical engineering departments are almost alien to Microfluidics. As an exception, the chemical engineering department at Iran University of Science and Technology is active in this field. This paper strongly recommends that Iranian chemical engineering researchers and faculty members make a time to do research on Microfluidics or at least, hold some courses in this field in order to prevent the scientific and technological gap among Iranian societies and developed countries from proliferating.

Produced water is one of the major drawbacks of petroleum production. Desalination is the most important step in controlling the produced water. Capability of electrodialysis in desalination of produced water was demonstrated by a sample containing a TDS of 4393 ppm using a flow rate of 0.3 L/min in an electrodialysis stack for 360 minutes. Desalination of %62 implied that this method was viable to produce required water for livestocks and agricultural uses from relatively thin produced water. To figure out the influences of feed flow rate, applied voltage, and duration of the process on the performance of electrodialysis, L9 array of Taguchi method was used to design the experiments. After conducting all designed experiments, it was concluded that the duration of the process and the applied voltage had direct relationships with the amount of separation, while there was an inverse relationship between the feed flow rate and the desalination of electrodialysis. Among the process variables, the period of the process had the most noticeable influence on the separation, while the feed flow rate had the least effect on desalination. In the vicinity of implied operating conditions the voltage of 7 V, flow rate of 0.3 L/min, and time duration of 200 min were obtained as the optimum conditions for desalination of produced water.

A Number of Industries release large amounts of water vapor into the atmosphere through their stacks. The flue gas can be a potential source for obtaining the required water for those industries. Separation process of water vapor by means of membrane condenser exchanger was studied. Numerical simulation of the process was conducted by COMSOL software using computational fluid dynamics. Simulation was based on solving conservation equations for solute in the membrane condenser exchanger. The tube wall is made of a specially designed porous material that is capable to extract condensated liquid from the flue gas. The tubes capture، recover، and reuse sensible and latent waste heat، along with the water vapor from the exhaust or flue gas. The clean water can be returned to the system. The nanoporous ceramic membrane tubes capture water via capillary condensation، which occurs more readily within nanoporous ceramic pores rather than with typical steel finned tube economizers. Comparison of the model results with experimental data proved the validity of the model with a deviation of less than 6%. The achieved results indicated that 20% of water and energy could be recovered only by a temperature reduction less than 10 °C if the flue gas was in regular conditions (60 °C < T <90 °C and 10% < RH < 20%).