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Reactive Crystallization in an Impinging Jets Reactor
, M.Sc. Thesis Sharif University of Technology ; Molaei Dehkordi, Asghar (Supervisor)
Abstract
Reactive crystallization or precipitation is an important industrial process. Many chemicals and biochemicals such as catalysts and pigments are produced by precipitation. Because of the advantages of impinging jets in chemical engineering processes, the main aim of this research was to investigate the application of this method in precipitation and to study the effects of different operating and design parameters on the product’s quality and properties. Two chemical models of barium sulfate and copper oxalate were used as main products. Each of these chemicals was produced by a liquid-liquid reaction of two aqueous solutions, which were fed to an impinging-jets reactor. Effects of...
Investigation and Optimization of Ni-P-Zn Electroless Alloy Coatings
, M.Sc. Thesis Sharif University of Technology ; karam, SaeedAllah (Supervisor) ; Dolati, Abolghasem (Supervisor)
Abstract
An optimization condition for obtaining Ni-Zn-P electroless alloy coating has been developed. The sulphate bath with sodium hypophosphate as a reducer and sodium citrate and ammonium chloride as complexing agents were used. The effect of variation in the pH level , temperature , time of deposition and reactants concentration on stability of bath, coating composition, microstructure, microhardness and corrosion resistance of coatings was investigated. The composition of coatings was obtained by using the EDAX analysis. To investigate coating morphology, SEM images were taken and to study the corrosion behavior of coatings potentidynamic polarization, Electrochemical Impedance Spectroscopy...
Experimental Study of Improved Oil Recovery by Low-Salinity Waterflooding in Asphaltenic Reservoirs
, M.Sc. Thesis Sharif University of Technology ; Ayatollahi, Shahaboddin (Supervisor) ; Vosoughi, Manouchehr (Supervisor)
Abstract
There is increasing evidence that injecting modified brines has a significant impact on the amount of oil recovered, but the exact mechanism by which this occurs is an unsettled issue, and is supposed to be a cause of the complex interactions occurring between the phases insitu. In this thesis, surface chemistry of smart water has been investigated. Fluid/solid and fluid/fluid interactions for Bangestan crude oil in tfhe presence of designed solutions and a set of dilutions of Persian Gulf seawater have been studied and compared. Fluid/solid interactions were investigated through wettability studies. Impact of salinity and ionic composition on this interaction was measured through contact...
Solphate Leaching of Titanium Minerals from Shore Reservoir of in the North of Iran and Refining of Iron and other Impurities
, M.Sc. Thesis Sharif University of Technology ; Yoozbashizadeh, Hossein (Supervisor)
Abstract
The most important raw material for production of titanium dioxide is titanium that used in Aerospace, Plastic, Pigment and Pharmacy industries. Due to the presence of titanium minerals in Iran, reduce imports of titanium dioxide is one of the goals of the Ministry of Industries and Mines to achieve self-sufficiency in the production of TiO2.One of the very rich sources of titanium is alluvial sands in northern of Iran. In this study the TiO2 high grade pigment production from these sources has been investigated. Titanium-bearing sands with 9.5% TiO2 are used to produce high grade TiO2 pigment. After magnetic separation stage and reach a purity of 16.2% TiO2, upgrading slag step is not...
Experimental Investigation and Modeling of Nanoparticles Synthesis by Reactive Precipitation and Using a Spinning Disk Reactor
, Ph.D. Dissertation Sharif University of Technology ; Shahrokhi, Mohammad (Supervisor) ; Molaei Dehkordi, Asghar (Supervisor)
Abstract
In this research work, to enhance the performance of the conventional spinning disk reactors, a novel type of spinning disk reactor has been proposed and tested successfully through the synthesis of barium sulfate nanoparticles by means of the reactive precipitation. This reactor consists of two coaxial rotating disks placed horizontally in a cylindrical chamber. The experimental results clearly indicate the capability of the proposed reactor in the synthesis of nanoparticles with the smaller mean particle size and the narrower particle size distribution compared to those obtained in various process intensification devices such that barium sulfate nanoparticles with a mean particle size of...
TiO2 Production by Acid Leaching of Upgraded Titanium Slag
, M.Sc. Thesis Sharif University of Technology ; Askari, Masoud (Supervisor)
Abstract
In Iran, titanium dioxide is still not produced and imports of titanium dioxide are required by various industries, including dyeing, electrodeposition, plastics and Therefore, according to the Ministry of Industries and Mines objectives, to obtain the technology of extraction Ti and TiO2, a research was carried out on titanomagnetite concentrate, extracted from the minerals of the plancher titanumitent and low-grade kahnoj. In this research, titanium dioxide is produced by sulfate method. Solid state recovery and magnetic separation were used to isolate titanium and iron. The dissolution process was then performed to achieve maximum dissolution. At this stage, the effects of temperature,...
Application of Sulfur Degrading Bacteria in Bioremediation
, M.Sc. Thesis Sharif University of Technology ; Kariminia, Hamid Reza (Supervisor)
Abstract
The main objective of this research was to evaluate the application of a new strain of Brevundimonas naejangsanensis which is newly identified sulfate-reducing bacteria (SRB), in bioremediation. A laboratory scale packed bed reactor (PBR) was fabricated and operated to study the new bacteria’s feasibility on SO_4^(2-) reduction. The reactor was packed with polyurethane foam cubes and operated under different feeding and operating conditions of HRT, COD/SO_4^(2-) ratio and salinity. A maximum SO_4^(2-) reduction of 73.6% was achieved in the PBR when operated at an HRT of 12 h with SO_4^(2-) concentration of 670 mg/L, COD/SO_4^(2-) ratio of 1 and salinity of 3%. The results show that this...
Some Studies on Conjugation of Nanoparticles Fe3O4 (Fe2O3) to PEG for Drug Delivery Systems
, M.Sc. Thesis Sharif University of Technology ; Vossoughi, Manouchehr (Supervisor) ; Yaghmaei, Soheila (Supervisor)
Abstract
The main strategy for treating solid cancers is based on the very early diagnosis of a malignant tumor, and in general the smaller the tumor, the greater the likelihood of successful treatment. Magnetic Resonance Imaging (MRI), based on the nuclear magnetic resonance phenomenon, provides the possibility of detecting early malignant tumors with the assistance of appropriate contrast agents. Hence, researchers continue to develop novel magnetic materials to achieve this aim. Superparamagnetic nanoparticles have become the focus of these studies because their superparamagnetic, biocompatible and hydrophilic properties would be revealed after modifying the particle surface by suitable...
Removal of Radioactive Elements from Liquid Waste of Bushehr Nuclear Power Plant with Resin
, M.Sc. Thesis Sharif University of Technology ; Samadfam, Mohammad (Supervisor) ; Sepehrian, Hamid (Supervisor) ; Fasihi, Javad ($item.subfieldsMap.e)
Abstract
In this study, granular activated carbon has been modified by potassium nickel hexacyanoferrate ( KNCF), sodium dodecyl sulfate(SDS) and ammonium per sulfate(APS) as new adsorbents for cesium, cobalt and chromium(VI), respectively. The prepared adsorbents were characterized using powder X-ray diffraction(XRD), nitrogen adsorption-desorption isotherm data, infrared spectroscopy, scanning electron microscopy coupled with energy dispersive spectroscopy(SEM-EDS) and their adsorption performance were investigated. The effect of various parameters like the initial pH value of the solution, contact time, temperature, strength ionic of the solution, interference ions and the initial concentration of...
Surface Modification and Stabilization of TiO2 Nanoparticles for Sonodynamic Therapy
, M.Sc. Thesis Sharif University of Technology ; Maddah Hosseini, Hamid Reza (Supervisor)
Abstract
Sonodynamic therapy has been developed over the last century, now it has become more widely used as a medical tool for the treatment of various diseases such as cancer. This technique involves delivery of sonosensitizing drugs, irradiation of ultrasound waves and motivation of drugs. In this thesis surface modification process with polymer and biocompatible surfactant on TiO2 nanoparticles has been done due to stabilization of TiO2 nanoparticles in neutral pH which is similar to inside-body situation. In the last step, for cancer therapy, doxorubicin as a cancer drug was loaded on TiO2 which was surface modified by PVA. The results revealed the best ratio of (PVA: TiO2), (SDS: TiO2), (SDS:...
Experimental Investigation of the Durability of Rammed Earth Materials in Different Environments
, M.Sc. Thesis Sharif University of Technology ; Toufigh, Vahab (Supervisor)
Abstract
Rammed earth structures have attracted the attention of engineers and researchers in recent years due to their economic advantages, sustainable development, and environmental sustainability. One of the main concerns for public opinion for acceptance of Rammed Earth as a reliable construction material is their durability. Previous studies have investigated the durability of rammed earth materials by conducting wet and dry cycle test, accelerated erosion test, and rain simulation in the laboratory environment. This research studied the durability of cement stabilized rammed earth (CSRE) for one year under the aggressive environments. Three cement contents were considered for preparing the CSRE...
Investigation of Sulfate Reducing Bacteria for Treatment of Wastewaters Polluted by Heavy Metals
, M.Sc. Thesis Sharif University of Technology ; Kariminia Hamedani, Hamid Reza (Supervisor) ; Borghei, Mehdi (Supervisor)
Abstract
The main objective of this research was to evaluate the application of a new strain of Brevundimonas naejangsanensis which is newly identified sulfate-reducing bacteria (SRB), in chromium(VI) removal in contaminated wastewater. A laboratory scale packed bed reactor (PBR) was fabricated and operated to study the bacteria’s feasibility on chromium(VI) reduction and removal. The reactor was packed with polyurethane foam cubes and operated under different feeding and operating conditions of HRT, COD/〖SO〗_4^(2-) ratio and influent chromium(VI) concentration. A maximum chromium removal of 94.6% was achieved in the PBR when operated at an HRT of 24 h with COD/〖SO〗_4^(2-) ratio of .70 and influent...
Microscopic Investigation of Formation Damage Inhibitor Effects during Low Salinity Water Injection
, M.Sc. Thesis Sharif University of Technology ; Ayatollahi, Shahab (Supervisor) ; Taghikhani, Vahid (Supervisor)
Abstract
Quartz crystal microbalance (QCM) is a piezoelectric sensor used to measure the mass of adsorbent deposition at the nanoscale on the surface, real-time and non-destructively. The QCM technique has recently gained extensive attention in the chemical and oil industries and other research fields such as medicine and nanotechnology due to its various applications in the advanced sciences. This technique provides comprehensive insights to scientists in the field of phase equilibrium of low-solubility and solid-liquid interactions. Therefore, many attempts have been made to investigate the interaction phenomenon mechanistically using QCM.Scale formation can have many adverse effects, and...
Continuous Synthesis of Nanoparticles in a High Speed SDR
, M.Sc. Thesis Sharif University of Technology ; Molaei Dehkordi, Asghar (Supervisor)
Abstract
In this research work, a new spinning disk reactor has been proposed and tested successfully for the synthesis of barium sulfate nanoparticles through the reactive precipitation. The proposed reactor consisted of a horizontal spinning disk with high rotation speeds (i.e., 6,000 to 15,000 rpm) that was located in a cylindrical chamber. The Barium sulfate reactive precipitation was used as a benchmark reaction to evaluate the performance of this reactor in the synthesis of nanoparticles. The reactive precipitation process in this reactor was carried out continuously by contacting two feed streams, barium chloride, and sodium sulfate solutions, on the surface of the spinning disk. The purpose...
Fabrication of Bioactive Bone Cement
, M.Sc. Thesis Sharif University of Technology ; Bahrevari, Mohammad Reza (Supervisor) ; Mashayekhan, Shohreh (Supervisor) ; Abd Khodaei, Mohammad Jafar (Supervisor)
Abstract
PMMA bone cement lacks biodegradability and the ability to bond with surrounding bone tissue. Therefore, the development of a new generation of bioactive bone cements that are biodegradable and possess adequate mechanical properties as well as desirable setting time is receiving remarkable interest.In this study, we have developed novel mineral-based bioactive bone cements. Our mineral bioactive bone cements were composed of Calcium Sulfate Hemihydrate, Bioactive Glass, and Tricalcium Silicate. Firstly, a binary system composed of Calcium Sulfate Hemihydrate and Bioactive Glass was optimized based on mechanical and setting behavior. Secondly, Tricalcium Silicate was added to the powder phase...
, M.Sc. Thesis Sharif University of Technology ; Afshar, Abdollah (Supervisor)
Abstract
Microbiologically influenced corrosion has substantial role in degradation of steel pipelines. It is believed that 20% of total corrosion damages are related to microbial corrosion. The most important micro-organisms which affect this type of corrosion are Sulfate Reducing Bacteria (SRB). Although many studies have been done on the effect of SRB on corrosion of buried steel pipelines, no decisive and identical thought has been made so far. In the present study, the role of SRB on corrosion of API 5L X65 steel in different conditions was investigated by performing weight loss, linear polarization, electrochemical impedance spectroscopy and X-ray diffraction tests. Experiments were...
Characterization of Protein Content in Soluble Microbial Products Involved in Fouling of Membrane Bioreactor
, M.Sc. Thesis Sharif University of Technology ; Torkian, Ayoub (Supervisor) ; Mousavi, Reza (Supervisor)
Abstract
Membrane bioreactors are increasingly being used for treatment of domestic and industrial effluents. A major operational drawback of this system is membrane fouling attributed to soluble microbial products (SMPs). In this study sampling were taken from microbial products on the surface and within the membrane pores and mixed liquir for mass characterization of protein content. Water-washing was used for surface and reversible portion of pore samples. Chemical wash with urea was used for further cleansing of SMPs within the pores. All samples were concentrate by precipitation with ammonium sulfate salt prior to analysis. Total protein content of samples was measured by lowry method. SDS-PAGE...
Experimental investigation of dynamic asphaltene adsorption on calcite packs: The impact of single and mixed-salt brine films
, Article Canadian Journal of Chemical Engineering ; Volume 97, Issue 7 , 2019 , Pages 2028-2038 ; 00084034 (ISSN) ; Ghotbi, C ; Jafari Behbahani, T ; Bakhshi, P ; Sharif University of Technology
Wiley-Liss Inc
2019
Abstract
In this study, the dynamic adsorption of asphaltene on a calcite surface is investigated. This study investigates the effect of mixed-salt brines on asphaltene adsorption. The results of this work can facilitate the understanding of the complex wettability behaviour of carbonate reservoirs. All experiments were performed in porous media, which were sand-packs filled with calcite powder, to study the influence of the type and concentration of salt on adsorption. The experiments were conducted with asphaltene concentration of 500 mg/L for brines of NaCl, Na2SO4, and a mixture of the two at various ionic strengths. In addition, two tests were performed with an asphaltene concentration of 2000...
Mass transfer coefficients of extracting Mo (VI) and W (VI) in a stirred tank by solvent extraction using mixture of Cyanex272 and D2EHPA
, Article Separation Science and Technology (Philadelphia) ; 2019 ; 01496395 (ISSN) ; Torab Mostaedi, M ; Outokesh, M ; Asadollahzadeh, M ; Sharif University of Technology
Taylor and Francis Inc
2019
Abstract
In this study, the mass transfer evaluation of an agitated liquid-liquid system for the extraction of molybdenum and tungsten from aqueous sulfate solution was investigated. It was found from batch experiments for separation of molybdenum from tungsten that the initial aqueous pH, Cyanex272 and D2EHPA concentration, contact time, dispersed phase volume fraction and impeller speed were optimized at 1.3, 0.07 M, 0.29 M, 15 min, 0.09 and 280 rpm, respectively. The results indicate that a suitable composition for stripping is 1.5 M NH4OH and 0.6 M NH4F. Furthermore, a modified correlation based on dimensionless numbers was derived for the prediction of continuous phase mass transfer in the...
Thermophysical interface properties of crude oil and aqueous solution containing sulfate anions: experimental and modeling approaches
, Article Petroleum Science and Technology ; Volume 37, Issue 21 , 2019 , Pages 2167-2173 ; 10916466 (ISSN) ; Ayatollahi, S ; Sharif University of Technology
Taylor and Francis Inc
2019
Abstract
Sulfate anion is well-known for being one of the most active agents to be injected into the oil reservoirs and being capable of not only altering the interfacial properties of crude oil but also enhancing the water solution properties in oil recovery. In the current study, the effects of temperature and pressure were studied on interfacial tension (IFT) as well as the adsorption behavior of two different solutions containing sulfate anion using experimental measurements and modeling approaches. Although it was expected that IFT values of the studied systems might decrease as temperature increased due to the improvement in the molecule mobility and solubility of crude oil in water, which...