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oxidation-process
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Density functional theory prediction for oxidation and exfoliation of graphite to graphene
, Article Applied Surface Science ; Volume 256, Issue 24 , 2010 , Pages 7596-7599 ; 01694332 (ISSN) ; Iraji Zad, A ; Sharif University of Technology
Abstract
A density functional theory (DFT) study of graphene synthesis from graphite oxidation and exfoliation is presented. The calculated DFT results for O adsorption predict CO as a most stable bond on the graphene oxide (GO) sheet. The obtained exfoliation energy for the graphene and the GO are 143 and ∼70 mJ/m2 that verify easier exfoliation of the graphite oxide compared with the graphite. Furthermore, the DFT results show that for decreasing the exfoliation energy of the GO at least two layers of the graphite should be oxidized during the oxidation process
Simultaneous Use of Dispensers and Advanced Oxidation Processes for Degradation of Oil Polluted Water
, M.Sc. Thesis Sharif University of Technology ; Abrishamchi, Ahmad (Supervisor)
Abstract
Chemical dispersants applied to the surface of Persian Gulf during the oil spill in 2010 were more than one million gallons. Following the addition of dispersants, oil mixes below the seawater surface and can be degraded or dissolved into the water column. The aforementioned condition is a perfect opportunity for degradation of organic pollutants using Ultraviolet light emitting diodes Advanced Oxidation Processes (AOPs). These methods are based on activation of oxidants such as persulfate and hydrogen peroxide to generate extremely reactive radicals. Dispersants would increase the degradation rate by providing more active area (homogenous solution) for these radicals. AOPs have shown to...
The Investigation of Sanitary Wastewater Disinfection Using Ultra Violet Light Irradiation in Conjunction with (TiO2+Fe2 O3 ,TiO2,H2 O2 )
, M.Sc. Thesis Sharif University of Technology ; Moslemi, Mohammad Reza (Supervisor) ; Erhami, Mohammad (Supervisor)
Abstract
Numerous strategies have been applied to deal with the drought crisis such as reusing the effluent wastewater in irrigating crops, sports spaces, parks, health, entertainment purposes etc.Although the common treatment of sewage can eliminate almost 95% to 99% of microorganisms but this level of treatment is not enough for reusing the sewage, due to the existence of Pathogenic microorganisms. Therefore, disinfecting the wastewater effluent is one of the crucial stages of sewage’s treatment for preserving water resources or reusing it. Chlorination is the most common method of disinfecting wastewater. However, using a wastewater which is disinfected through Chlorination has Harmful effect on...
Application of Advanced Oxidation Processes and Biological Methods to Degrade Levofloxacin
, M.Sc. Thesis Sharif University of Technology ; Yaghmaei, Soheila (Supervisor) ; Ghasemian, Saloumeh (Supervisor) ; Ghobadinejad, Zahra (Supervisor)
Abstract
Levofloxacin has been widely used in recent years as an antibiotic in the treatment of various bacterial infections. This drug compound is known as a newly emerging contaminant. In this study, the degradation of this pollutant has been investigated using advanced oxidation processes, biological process, and a combination of advanced oxidation-biological processes. In order to evaluate the degradation of levofloxacin with advanced oxidation processes, an electrochemical process was used. Advanced oxidation processes were carried out to optimize initial concentration parameters of the contaminant (5-15 milligrams per liter), electrolyte concentration (2.5-10 grams per liter), and current...
Reactivity and characteristics of Pd/MOF and Pd/calcinated-MOF catalysts for CO oxidation reaction: Effect of oxygen and hydrogen
, Article International Journal of Hydrogen Energy ; Volume 46, Issue 24 , 2021 , Pages 12822-12834 ; 03603199 (ISSN) ; Karimi Sabet, J ; Ghotbi, C ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
For the first time, the effect of calcination process on characteristics and catalytic performances of Pd supported on different MOFs (MIL-101(Cr), NH2-MIL-101(Cr), and HKUST-1) was evaluated. Besides, the various orders of calcination process and reduction one on Pd/MOF and Pd/calcinated-MOF were studied, and their performances in CO oxidation reaction were presented to find the effect of H2 and O2. Results showed that the effect of calcination and reduction processes on the catalytic activities and characteristics strongly depends on the nature of MOF. Among MIL-based catalysts, the catalyst with no calcination treatment showed the best activity. Among MNH2-based catalysts, high activity...
Reactivity and characteristics of Pd/MOF and Pd/calcinated-MOF catalysts for CO oxidation reaction: Effect of oxygen and hydrogen
, Article International Journal of Hydrogen Energy ; Volume 46, Issue 24 , 2021 , Pages 12822-12834 ; 03603199 (ISSN) ; Karimi Sabet, J ; Ghotbi, C ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
For the first time, the effect of calcination process on characteristics and catalytic performances of Pd supported on different MOFs (MIL-101(Cr), NH2-MIL-101(Cr), and HKUST-1) was evaluated. Besides, the various orders of calcination process and reduction one on Pd/MOF and Pd/calcinated-MOF were studied, and their performances in CO oxidation reaction were presented to find the effect of H2 and O2. Results showed that the effect of calcination and reduction processes on the catalytic activities and characteristics strongly depends on the nature of MOF. Among MIL-based catalysts, the catalyst with no calcination treatment showed the best activity. Among MNH2-based catalysts, high activity...
Removal of Micropollutants using the Combination of Advanced Oxidation Process and Bioreactor
, M.Sc. Thesis Sharif University of Technology ; Ghasemian, Saloumeh (Supervisor) ; Ghobadi Nejad, Zahra (Supervisor)
Abstract
Micropollutants are a wide group of organic compounds that are detected in most compartments of the environment. Their environmental concentration is usually in the range of few ng/l to mg/l, but they remain biologically active even at such low concentrations; may be accumulated through the food chain, and pose a serious threat to the environment, fauna, and human health. Among micropollutants, pharmaceutical active compounds (PhACs) are of special concern. It is accepted that the main sources of PhACs in the environment are effluents from wastewater treatment plants (WWTPs), where conventional activated sludge processes are not able to degrade most of them. To address these concerns, the...
On the significance of hydroxide ion in the electro-oxidation of methanol on Ni
, Article Journal of Electroanalytical Chemistry ; Volume 650, Issue 2 , January , 2011 , Pages 219-225 ; 15726657 (ISSN) ; Valadbeigi, Y ; Kasmaee, L. M ; Sharif University of Technology
2011
Abstract
Electro-oxidation of methanol on Ni in NaOH solutions with the alkali concentration in the range of 0.05-0.5 M and in the presence of 0.5 M Na 2SO4 supporting electrolyte is studied. All the mentioned species compete for adsorption on Ni and OH- is essential for the electro-oxidation process. The electro-oxidation seems to proceed through the electro-chemical reactions of adsorbed methanol and hydroxide species and the removal of the resulting intermediate by adsorbed hydroxyl groups. The mechanism is consistent with the cyclic voltammetry and impedance spectroscopy results and can semi-quantitatively account for the appearance of capacitive, inductive and negative resistance loops as well...
Effective degradation of Reactive Red 195 via heterogeneous electro-Fenton treatment: theoretical study and optimization
, Article International Journal of Environmental Science and Technology ; 2018 ; 17351472 (ISSN) ; Setayesh, S. R ; Sharif University of Technology
Center for Environmental and Energy Research and Studies
2018
Abstract
Abstract: The magnetite (Fe3O4) nanoparticles were synthesized and supported on the reduced graphene oxide. The characterization of the catalyst was performed by FT-IR, VSM, SEM, XRD, and BET techniques. The obtained results indicated that the in situ synthesis of Fe3O4 using coprecipitation method caused the homogenous formation of magnetite nanoparticles on the surface of reduced graphene oxide (average particle size ~ 71.032 nm) with high stability and catalytic activity toward electro-Fenton removal of Reactive Red 195. The effect of various factors (current intensity, initial pollutant concentration, catalyst weight, and pH) was evaluated by response surface methodology using central...
A systematic investigation on the bactericidal transient species generated by photo-sensitization of natural organic matter (NOM) during solar and photo-Fenton disinfection of surface waters
, Article Applied Catalysis B: Environmental ; Volume 244 , 2019 , Pages 983-995 ; 09263373 (ISSN) ; Giannakis, S ; Gholami, M. R ; Feng, L ; Pulgarin, C ; Sharif University of Technology
Elsevier B.V
2019
Abstract
In this work, the role of dissolved oxygen in the solar and the photo-Fenton-mediated E. coli inactivation process was put under scrutiny. The effect of transient species that were produced in the presence of various natural organic matter isolates (NOM), namely Suwannee River (SR) NOM, Nordic Reservoir (NR) NOM, SR Humic acid (SRHA), and SR Fulvic acid (SRFA) was studied in detail. The role of 1 O2 in this reaction was systematically evaluated by modifying the O2 concentration (N2/O2 purging) and the matrix composition (10, 50, and 100% deuterium oxide (D2O) v/v). In the presence of NOM, 1 O2 was generated and the enhancement of E. coli inactivation rate due to charge transfer from triplet...
Photocatalytic degradation of vancomycin using titanium dioxide and optimization by central composite design
, Article International Journal of Environmental Science and Technology ; Volume 19, Issue 9 , 2022 , Pages 8957-8968 ; 17351472 (ISSN) ; Yousefinejad, S ; Dehghani, M ; Borghei, S. M ; Javid, A. H ; Sharif University of Technology
Springer Science and Business Media Deutschland GmbH
2022
Abstract
Conventional wastewater treatment processes are not completely effective in removing vancomycin. In this study, affecting parameters on vancomycin degradation, such as pH, catalyst, initial vancomycin concentration, temperature, and reaction time were investigated simultaneously during a removal process based on titanium dioxide with ultraviolet irradiation in an aqueous solution. Titanium dioxide was synthesized and characterized using X-ray diffraction and scanning electron microscopy. The average size of the synthesized crystals was 4.7 (± 0.2) nm. Design of experiments was done by a central composite design based on the response surface methodology and multiple linear regression was...
Kinetics Investigation of Photocatalytic Degredation of Environmental Organic Pollutants Using ZnO-Zeolite Nano Composites
, M.Sc. Thesis Sharif University of Technology ; Gholami, Mohammad Reza (Supervisor) ; Sajadi, Ali Akbar (Supervisor)
Abstract
ZnO nano particles and mordnite zeolite nano particles were prepared by precipitation method and hydrothermal method,respectively. The influence of solvent and surfactant in ZnO nano particles synthesis were studied to reform the structure of nano particles.These nano particles were based on different supports to improve and enhance their photocatalytic activities. Synthesized catalysts characterized by X-ray diffraction (XRD), Scanning electron microscopy (SEM), Fourier transform-infra red spectra (FTIR), UV-Vis spectroscopy and BET techniques. To investigated photocatalytic activity of the synthesized catalysts under UV irradiation, they were used to degradation bio-environmental...
Some Investigation on Humic Acid Removal From Aquaous Solutions Using Nanophotocatalytic UV/TiO2 Process
, M.Sc. Thesis Sharif University of Technology ; Vosoughi, Manouchehr (Supervisor)
Abstract
Humic compounds are considered the most portion of natural organic matter (NOM) found in many surface water sources.Humic substances have been known as precursors to disinfection by-products.because conventional treatment process can not meet disinfection by-product standards,novel method have been increasingly applied for the removal of disinfection by-products precursors.The〖UV/TiO〗_2 process is one of the advanced oxidation process using the photocatalytic technology.The most important advantages of this process are its stability and high efficiency removal.The present study aims to investigate the effect of 〖UV/TiO〗_2photo-catalytic technology on removal of humic substances.In this...
Kinetics Investigation of the Degradation of Environmental Pollutants by Fenton and Electro-Fenton Processes using Nanomagnetite and Nano Magnetite Supported by Activated Carbon
, M.Sc. Thesis Sharif University of Technology ; Rahmansetayesh, Shahrbano (Supervisor)
Abstract
The progress and the development of various industries, pollutants derived from the agricultural and industrial processes contaminate the environment. The degradation of these pollutants have an important effect on the environment.Magnetite (Fe3O4) nanoparticles and magnetite supported on functionalized activated carbon were synthesized and characterized by different techniques such as SEM, FT-IR, XRD, BET and VSM. The catalyst activity of these nanocatalysts was evaluated by the degradation of reactive red ME4BL (RRME4BL) textile dye in heterogeneous Fenton and electro-Fenton processes as a model pollutant. The effect of several parameters such as H2O2, RRME4BL concentration, the amount of...
Experimental Studies on Photocatalytic Removal of Dye Using Titanium Dioxide and Zinc Oxide Nanoparticles
,
M.Sc. Thesis
Sharif University of Technology
;
Kariminia, Hamid Reza
(Supervisor)
;
Vossoughi, Manoochehr
(Supervisor)
Abstract
Textile industry wastewaters are one of the important sources of environmental contamination because they produce large quantities of highly colored effluents. In recent years, use of advanced oxidation processes by producing highly active and reactive components such as hydroxyl radicals has been proposed. In this study, two oxygenated photocatalytic systems including UV/ZnO and UV/TiO2 were examined for degradation of C.I. reactive orange 16 dye as a typical organic pollutant in textile effluents. A thin gap annular photoreactor was designed and applied for the experiments. The photoreactor provided large surface area exposed to UV light, where in the solution layer renewal on the UV...
Kinetics Investigation of Environmental Pollutants Degradation in Advanced Oxidation Processes Using Metal Oxide Nanocatalysts
, Ph.D. Dissertation Sharif University of Technology ; Rahman Setayesh, Shahrbanoo (Supervisor)
Abstract
In this project, metal oxides loaded on different supports were used in the heterogeneous electro-Fenton (EF) process for organic pollutants removal. At first, Fe3O4/AC was synthesized for catechol degradation as a phenolic compound. 98.2% removal of catechol was achieved by operational conditions optimization. The catalytic activity of Fe3O4/AC was remained constant after 6 cycles. In the other study, reduced graphene oxide was used as a support for the magnetite nanoparticle catalyst. The catalytic activity of Fe3O4/rGO in EF degradation of reactive red 195 (RR195) dye was studied and 93.34% removal was obtained. Response surface methodology (RSM) was used and a quadratic model with...
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,...
Synthesis and Characterization of TiO2-SnO2 Core-shell Nanoparticles
, M.Sc. Thesis Sharif University of Technology ; Ghorbani, Mohammad (Supervisor) ; Mohammadi, Mohammad Reza (Supervisor)
Abstract
Nowadays, heterogeneous photocatalytic processes have attained a particular importance among the other advanced oxidation processes in purification of organic polluted wastewaters. Titanium oxide is the most popular photocatalyst because of its strong oxidizing abilities for decomposition of organic pollutants, superhydrophilicity, chemical stability, long durability, non-toxic nature, and low cost. Same as other semiconductors, high recombination rate of charge carriers is the main weakness that cause decreases in photocatalytic efficiency. One of the solutions is coupling this material with other semiconductors. Core-shell nanoparticles are the type of these composites that show high...
Enhancing Biological Removal Yield of Microplastics Using Advanced Oxidation Processes (AOPs)
, M.Sc. Thesis Sharif University of Technology ; Ghasemian, Saloumeh (Supervisor) ; Yaghmaei, Soheila (Supervisor) ; Ghobadinejad, Zahra (Supervisor)
Abstract
Statistics show that plastic production in the world is increasing, with 335 million tonnes in 2016 reaching 367 million tonnes in 2020. Since the presence of plastics in the dimensions of micro and nano, especially in aquatic environments can have adverse effects on human health and other living organisms, it has raised major environmental concerns. Therefore, it is necessary to think of measures to remove them and develop efficient methods for eliminating and decomposing microplastics. Recently, the advanced oxidation processes have attracted much attention because of the ability to eliminate recalcitrant compounds. In this study, electrochemical techniques and Fenton-based techniques for...
Oxygen diffusion mechanism in MgO-C composites: An artificial neural network approach
, Article Modelling and Simulation in Materials Science and Engineering ; Volume 20, Issue 1 , December , 2012 ; 09650393 (ISSN) ; Nemati, E ; Sharif University of Technology
2012
Abstract
An artificial neural network (ANN) model was used to predict the weight loss of MgO-C composites at different temperatures and graphite contents. The general idea of ANN modeling was presented and after that the empirical weight loss data were used for both model verification and assessment of the oxidation rate predictions. The model was proved to have an astounding power in predicting kinetic parameters of the oxidation process. Graphite oxidation was, for example, found to be controlled by alternative diffusion steps. Plotting the Arrhenius law curves for graphite oxidation indicated a distinguishable slope change at a critical temperature which is related to the graphite content. This...