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The influence of nanoparticles on hydrodynamic characteristics and mass transfer performance in a pulsed liquid-liquid extraction column
, Article Chemical Engineering and Processing: Process Intensification ; Volume 50, Issue 11-12 , 2011 , Pages 1198-1206 ; 02552701 (ISSN) ; Khoobi, N ; Mozdianfard, M. R ; Bahmanyar, H ; Sharif University of Technology
2011
Abstract
With respect to the influence of nanoparticles on mass transfer characteristics, limited number of studies available in the literature, deal primarily with gas-liquid systems. In this work, mass transfer performance and hydrodynamic characteristics including static and dynamic dispersed phase hold-ups of nanofluids have been investigated for pulsed liquid-liquid extraction column (PLLEC). The nanofluids used were prepared by dispersing SiO2 nanoparticles of 0.01, 0.05 and 0.1 volume percent with two different hydrophobicities in kerosene as base fluid using ultrasonication. UV-vis spectrophotometer was also used for evaluation of the nanofluids stability. The results were compared with...
Design and Fabrication of a Swimmer Robot at Low Reynolds Number
, Ph.D. Dissertation Sharif University of Technology ; Sayyadi, Hassan (Supervisor)
Abstract
Helical swimming robots with a capable propulsion system at low Reynolds numbers have been proposed for many applications. Although linear propulsion characteristics of swimming robots with a single helical flagellum have been extensively studied, the characteristics of maneuverability have not been completely investigated yet. In this thesis two novel mechanisms was proposed. The first mechanism presents a new method for the maneuverability of the helical swimming robot with a single helical flagellum. This mechanism is based on the change in the angle between the helical and body axes. This study shows that a change in the aforementioned angle can enable the swimming robot to have turning...
Preparation and Properties of Ethylene-vinyl Acetate/linear Low-density Polyethylene/Graphene Oxide Nanocomposite Films
, Article Polymer - Plastics Technology and Engineering ; Volume 54, Issue 11 , 2015 , Pages 1152-1158 ; 03602559 (ISSN) ; Ramazani, S. A ; Baniasadi, H ; Sharif University of Technology
Taylor and Francis Inc
2015
Abstract
Ethylene-vinyl acetate-based nanocomposites with 18 and 28 wt% vinyl acetate were prepared via solution casting method. To improve the mechanical and barrier properties of ethylene-vinyl acetate, linear low-density polyethylene, and graphene oxide were introduced to matrix. The morphological studies indicated that the graphene oxide diffraction peak disappeared in all prepared nanocomposites, probably due to its exfoliation; also proper dispersion and good interaction between nanofillers and polymer matrix were achieved. By introducing low amount of graphene oxide into the matrix, the mechanical and thermal properties and oxygen permeability were improved especially for those with 28 wt%...
Investigation of Drop Phase Mass Transfer Coefficient During Rising Drops in a Pulse Sieved Plate Column in Presence of Nano Particles
, M.Sc. Thesis Sharif University of Technology ; Bastani, Daruoosh (Supervisor) ; Bahmanyar, Hossein (Supervisor)
Abstract
Nanofluids are new engineering materials with great potential for application in process industries. Their enhanced heat-transfer properties are reported in recent literatures. However, with respect to the influence of nanoparticles on mass transfer characteristics, limited number of studies available in the literature, deal primarily with gas-liquid systems. In this work, mass transfer performance and droplet behavior along a pulsed liquid-liquid extraction column, is studied where SiO2 nanoparticles with concentrations of 0.01, 0.05 and 0.1 vol% and different hydrophobicities are applied to the dispersed phase. Using ultrasonication, nanoparticles were dispersed in kerosene as the base...
Preparation of ethylene vinyl acetate copolymer/graphene oxide nanocomposite films via solution casting method and determination of the mechanical properties
, Article Polymer - Plastics Technology and Engineering ; Volume 54, Issue 2 , Jan , 2015 , Pages 218-222 ; 03602559 (ISSN) ; Sedaghat, S ; Ramazani S. A, A ; Baniasadi, H ; Sharif University of Technology
Taylor and Francis Inc
2015
Abstract
Ethylene vinyl acetate/graphene oxide (EVA/GO) nanocomposite films were prepared via solution casting method. The morphological studies investigated using SEM and XRD methods and the results confirmed the formation of likely exfoliation structures and good interaction between matrix and fillers. The results of permeability measurements showed that films have good resistance against oxygen. Mechanical measurements revealed that Young’s modulus and tensile strength of EVA have improved with introducing GO because of proper dispersion of GO into matrix and good interaction between them; however, elongation at break decreased due to formation of strong and rigid polymer/filler network preventing...
Photocatalytic Treatment of Azo based Textile Pollutants by Modified Bismuth Vanadate
, M.Sc. Thesis Sharif University of Technology ; Vossoughi, Manoochehr (Supervisor) ; Ghasemi, Shahnaz (Co-Supervisor)
Abstract
In recent years, because of the increase in population and more accessibility of health facilities for people, an increase has occurred in water resources consumption. Recycling water has become so much valuable as the freshwater of the world is limited. Besides the advantages of treated water has for people, discharging the untreated wastewater to the rivers could cause many problems for human health. Many kinds of pollutions, such as textile effluent, are not easy to be treated by traditional methods because of their resistance to them. As these types of wastewater have severe negative effects on living things (both humans and animals), new treatment technologies should be considered. The...
Removal of Non-biodegradable Contaminants from Colored Textile Wastewater Using Electro Oxidation Process
, M.Sc. Thesis Sharif University of Technology ; Borghei, Mehdi (Supervisor) ; Ghasemi, Shahnaz (Supervisor)
Abstract
In the present study, the electrochemical oxidation process was introduced as a green process for complete degradation and removal of non-biodegradable pollutants from aquatic environments and effluents of various industries without the need to use chemicals and toxins. Research stages include comprehensive preliminary studies in the field of electrochemistry and wastewater treatment, software design of electro-oxidation reactor using titanium mesh anode and stainless steel cathode mesh inside a body made of polypropylene, designed cell construction and then evaluation of device performance in polluting environment Are different. In software simulation using COMSOL MULTIPHYSICS software, it...
Design and Construction of Photocatalytic Reactor for the Removal of
Textile Azo-Dye Pollutants
,
M.Sc. Thesis
Sharif University of Technology
;
Rashtchian, Davood
(Supervisor)
;
Ghasemi, Shahnaz
(Supervisor)
Abstract
Population growth and community development has a large role in the demand for fresh water for a variety of uses. In recent decades, over-harvesting and abusing of water resources has led to water crisis. On the other hand, the increase in various pollutants, in addition to environmental hazards, is a threat to groundwater pollution and the existence of valuable fresh water. Due to the potential hazards of emerging pollutants, new treatment technologies such as advanced oxidation and photocatalytic methods are being developed. One of the contaminants resistant to traditional treatment methods is textile contaminants. In this research, by designing and constructing a photocatalytic reactor,...
Copper Adsorption by Nanoadsorbents Based Graphene Oxide from Industrial Wastewater
, M.Sc. Thesis Sharif University of Technology ; Borghei, Mehdi (Supervisor) ; Ghasemi, Shahnaz (Co-Supervisor)
Abstract
In this thesis, a novel graphene oxide (GO)/sodium alginate (SA)/polyacrylamide (PAM) ternary nanocomposite hydrogel with excellent mechanical performance has been fabricated through freeradical polymerization of acrylamide (AAm) and SA in the presence of GO in an aqueous system followed with ionically crosslinking of calcium ions. Physical and chemical characteristics of the composite were investigated by Fourier transform infrared spectroscopy and scanning electron microscopy. The swelling behaviors of the composite hydrogels were investigated under varying conditions of time and pH. The optimized swelling capacity in standard conditions was found to be 1711% per gram of the hydrogel. The...
Dyes Adsorption and Removal of Aqueous Solutions with Novel Adsorbents Based on Graphene Oxide
, M.Sc. Thesis Sharif University of Technology ; Borghei, Mahdi (Supervisor) ; Ghasemi, Shahnaz (Co-Supervisor)
Abstract
Nowadays, water pollution and water sources decreasion, is one of the important issues of our world. Treatment of polluted water and wastewater and recycling of those to industries and common uses, is very necessary. Dyes, is one of the biggest parts of water pollutants, especially, in textile plants. There are some ways for dye removal, in the industries; including biological, chemical and physical methods. Among of these methods, physical removal of dyes through adsorption (with Activated Carbon or other adsorbents), is very popular. Hydrogels are three-dimensional hydrophilic polymer networks, introducing very good swelling rate, mechanical properties and pollutants adsorption. In this...
Photocatalytic Reactor Design for Elimination of Pharmaceutical Pollutants from Wastewater
, M.Sc. Thesis Sharif University of Technology ; Borghei, Mehdi (Supervisor) ; Ghasemi, Shahnaz (Co-Supervisor)
Abstract
Due to the increasing number of Advanced Oxidation Processes (AOPs) that are exploited to eliminate emerging and recalcitrant contaminants from water supplies, photocatalytic degradation of Reactive Blue 21 dye using Zinc Oxide nanoparticles is investigated in both a slurry phase and an immobilized photoreactor. The structural and optical properties of the prepared ZnO nanoparticles were examined by X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and UV-Visible Diffuse Reflectance Spectroscopy (UV-vis DRS). The effects of photocatalyst concentration, calcination temperature, pH and UV lamps were optimized in the slurry phase photoreactor. It was shown that 250 ppm of ZnO that was...
Study of droplet behaviour along a pulsed liquid-liquid extraction column in the presence of nanoparticles
, Article Canadian Journal of Chemical Engineering ; Volume 91, Issue 3 , 2013 , Pages 506-515 ; 00084034 (ISSN) ; Bahmanyar, A ; Molavi, H ; Bastani, D ; Mozdianfard, M. R ; Bahmanyar, H ; Sharif University of Technology
2013
Abstract
In this article, droplet size and its distribution along a pulsed liquid-liquid extraction column, is studied where SiO2 nanoparticles with concentrations of 0.01, 0.05 and 0.1vol.% and different hydrophobicities are applied to the dispersed phase. Using ultrasonication, nanoparticles were dispersed in kerosene as the base fluid. Nanofluids' stability was ensured using a UV-vis spectrophotometer. Some 22,000 droplets were measured by photographic technique and results were compared with systems containing no-nanoparticles (Water-Acetic acid-Kerosene). Addition of nanoparticles changed the droplet shape from ellipsoidal to spherical. Also, there was a marked influence on droplet breakage and...
Improving the Photocatalytic Activity of Bismuth-Based Semiconductors Via Plasmonic Effects for Degradation of Non-Biodegradable Pollutants
, M.Sc. Thesis Sharif University of Technology ; Hamzehlouyan, Tayebeh (Supervisor) ; Ghasemi, Shahnaz (Supervisor)
Abstract
The ever-growing population and the rapid industrialization in recent years have left the world with serious environmental problems such as the shortage of water resources and pollution of existing resources. This shortage and pollution not only increase the mortality rate in certain regions of the globe but could cause the industry to falter. To address this problem, water treatment facilities are a logical and possible solution. Recently, water treatment using photocatalysis has attracted much attention. This process, which requires only a semiconductor (photocatalyst) and sunlight, has low energy consumption and does not produce harmful by-products (two problems traditional water...
Increasing the Efficiency of Light Absorption in Metal Oxide Photocatalysts using Quantum Dots to Remove Non-Biodegradable Pollutants
, M.Sc. Thesis Sharif University of Technology ; Hamzehlouyan, Tayebeh (Supervisor) ; Ghasemi, Shahnaz (Supervisor)
Abstract
In recent decades, the increasing presence of emerging contaminants such as pharmaceuticals, personal care products, and persistent organic compounds in water resources has raised serious environmental concerns. Due to their high stability and resistance to conventional treatment processes, these pollutants remain in surface and groundwater and can pose adverse effects on human health and ecosystems. Traditional water and wastewater treatment methods, including coagulation, filtration, and sedimentation, are largely ineffective in fully removing these compounds. In this context, advanced oxidation processes (AOPs), particularly photocatalytic degradation, have emerged as promising...
Improving the Activity and Efficiency of Tungstate Bismuth (Bi2WO6)-Based Photocatalysts in Removing Water Pollutants
, M.Sc. Thesis Sharif University of Technology ; khorasheh, Farhad (Supervisor) ; Ghasemi, Shahnaz (Supervisor)
Abstract
This research aimed to develop materials that can degrade organic pollutants and industrial dyes in water under visible light irradiation. In this study, an efficient material was prepared by combining bismuth tungstate (Bi2WO6), an organic polymer semiconductor called g-C3N4, and a metal-organic framework MIL-100(Fe). This combination was designed to have optimal performance in light absorption and pollutant degradation. A simple hydrothermal method was used to fabricate this material, which resulted in the formation of a ternary structure with specific properties. This structure includes bonds through which electrons generated when light is irradiated are rapidly transferred to different...
Labratoary Studies of Ozonation Pretreatment for Anaerobic Digestion of Waste Thickened Active Sludge
, M.Sc. Thesis Sharif University of Technology ; Vossoughi, Manouchehr (Supervisor) ; Ghasemi, Shahnaz (Supervisor)
Abstract
The best method for stabilizing sludge is anaerobic digestion, In addition to reducing the amount of volatile solids; it produces biogas, which can be considered as a sustainable energy source for wastewater treatment plants. However, the most important factor limiting the process of digestion is the sludge hydrolysis, the best way to increase the speed of hydrolysis is to pre-treatment the sludge before entering the digester; One of the most effective pretreatment methods is pre-treatment by ozone gas, This gas, which is highly unstable, quickly reacts with the wall of the bacterial cell and oxidizes it due to its high oxidizing properties And accelerates the process of sludge hydrolysis....
Coating of Sewage Pipes with Appropriate Nanomaterials Aimed at Preventing Biological Growth (Algae+Biofilm)
, M.Sc. Thesis Sharif University of Technology ; Borghei, Mehdi (Supervisor) ; Ghasemi, Shahnaz (Co-Supervisor)
Abstract
Biological layers are one of the main problems related to water transfer with pipe lines which are formed through time in the inner surface of the pipes by the water nutrients. Hence, the inner surfaces in the pipe lines and water refineries should be made in order not to let these biological layers to be made. The reason is that when the biofilm is formed on these surfaces, the traversing water is polluted. Dredging of these pipes is not only necessary in most of the countries in the world and needs huge amounts of water but is also very complex and expensive.In this research, nanomaterials, namely ZnO, T〖iO〗_2،S〖iO〗_2 have been used to cover the surface of concrete and steel pipes (The...
The effect of multiwalled carbon nanotubes and activated carbon on the morphology and photocatalytic activity of TiO2/C hybrid materials
, Article Catalysis Science & Technology ; 1 , Jan , 2011 , pp. 279-284 ; Ghasemia, S. (Shahnaz) ; Gholami, M. R. (Mohamad Reza) ; Sharif University of Technology
2011
Abstract
TiO2 nanoparticles supported on activated carbon (AC) and multiwalled carbon nanotubes (MWCNTs) were prepared by the sol–gel method using ultrasonic irradiation. All the prepared samples were calcined at different temperatures and characterized by X-ray diffraction, nitrogen adsorption/desorption isotherms, scanning electron microscopy, transmission electron microscopy and diffuse reflectance spectroscopy. The effects of size and type of carbon on the morphology and photocatalytic activity of the resulting hybrid materials were investigated. The results showed that a decrease in the size of the carbon led to a decrease in size of TiO2 nanoparticles. Both AC and MWCNTs retarded the...
Photocatalytic Reactor Design for Degradation of Bisphenol A
, M.Sc. Thesis Sharif University of Technology ; Borghei, Mahdi (Supervisor) ; Ghasemi, Shahnaz (Co-Supervisor)
Abstract
One of the Advanced Oxidation Process (AOP) is Photocatalyst method. Structure of this method is according to three foundation: 1. Catalyst, 2. Source of energy, 3. Wastewater. Progress of human activity around variety of fields such as pharmaceutical, plastic industry, and medical science has produced some micro pollutants such as Bisphenol A (BPA) that has aroused the public concerns in recent years. The half-life of this components in water, air and soil is too long, so typical methods such as biological method, activated sludge and carbon adsorption are inefficient in removing BPA. This work describes a visible light responsive Carbon Quantum Dots(CQDs) embedded on TiO_2 nanoparticles...
Kinetic Study of Non-Biodegradable Pollutant Degradation Process Using Improved Photocatalyst Based on Cerium
, M.Sc. Thesis Sharif University of Technology ; Hamzehlouyan, Tayebeh (Supervisor) ; Ghasemi, Shahnaz (Supervisor)
Abstract
Incomplete treatment of industrial wastewater, particularly in the textile industry, leads to the release of persistent pollutants such as dyes and heavy metals into water sources, which can harm the environment and cause diseases like cancer. Traditional treatment methods cannot fully remove these pollutants. Advanced oxidation processes (AOPs), by generating hydroxyl radicals, degrade these pollutants rapidly and effectively. In this study, a composite semiconductor material comprising bismuth vanadate, graphitic carbon nitride, and cerium vanadate was synthesized. This material was produced through two sequential hydrothermal processes, and its structural composition and surface...