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oxidative-degradation
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Investigation of vacuum annealing effects on physical-mechanical properties of thermoplastic parts
, Article Materials and Design ; Volume 26, Issue 1 , 2005 , Pages 89-93 ; 02613069 (ISSN) ; Mousavi, S ; Sharif University of Technology
Elsevier Ltd
2005
Abstract
Impact and tensile strength of polystyrene and nylon 6 samples, which have been produced by injection molding before and after annealing in different conditions are obtained. Polystyrene samples that are heated on vacuum conditions can deform highly even in temperatures much less than polystyrene glass temperature. This phenomenon is reduced significantly by heating samples to annealing temperature in atmospheric pressure and then removing air from sample environment in constant temperature. Deformation problems for nylon were not so important but due to high temperature implied for annealing of nylon parts, some color change due to oxidative degradation are observed. So for nylon parts a...
Application of Metallic Nanoparticles in Treatment of Wastewater Containing Dyestuffs
, M.Sc. Thesis Sharif University of Technology ; Shaygan, Jalalaldin (Supervisor)
Abstract
Textile industrial wastewaters are one of the most important sources of environmental contaminants. In the recent years, use of advanced oxidation processes, by producing highly active and reactive components such as hydroxyl radicals has been proposed. The aim of this research is oxidative degradation of methylene blue dye using Cu-nanoparticles immobilized on a polymer support with H2O2 as an oxidant reagent.In general, oxidative degradation of methylene blue with hydrogen proxide in the presence of immobilized CuO nanoparticles on a polymer support as the catalyst was studied. We used polyamidoamine (PAMAM) dendrimer as the polymer support for nanoparticles. fourth generation of PAMAM was...
Degradation of Polypropylene Random Copolymer in Aqueous Solution of Chlorine Dioxide: Effect of Crystalline Structure and Morphology
, M.Sc. Thesis Sharif University of Technology ; Pircheraghi, Gholamreza (Supervisor)
Abstract
Polypropylene is a semi-crystalline thermoplastic used in various industries and the second most used polymer globally. Polypropylene is sensitive to degradation by o agents due to having tertiary carbon in its chain. Chlorine-based disinfectants, used to disinfect drinking water, cause the degradation of hot water pipes made of polypropylene random copolymer. The stability of polypropylene against oxidizing chemical agents depends on the type of crystalline phase and polymer morphology. This research investigated the effect of alpha, beta, and gamma crystalline phases and spherulite size on random polypropylene copolymer's chemical stability in chlorine dioxide. Three samples were prepared,...
Photo-Fenton like degradation of catechol using persulfate activated by UV and ferrous ions: Influencing operational parameters and feasibility studies
, Article Journal of Molecular Liquids ; Volume 249 , 2018 , Pages 463-469 ; 01677322 (ISSN) ; Takdastan, A ; Borghei, S. M ; Sharif University of Technology
Elsevier B.V
2018
Abstract
In the present study, photo-Fenton degradation of catechol from aqueous solution was carried out using UV light and iron ions (Fe2+) as activators of persulfate (PS). Catechol degradation from solution was studied under different experimental variables such as solution pH (2.0–10.0), iron dosages (0.1–0.5 g/L), persulfate loadings (1.0–5.0 mM), initial catechol concentrations (20–100 mg/L) and scavengers (TBA and IPA). The comparative study of catechol removal showed that among the applied approaches, the order of degradation of catechol is as follows: PS/Fe2 +/UV > PS/Fe2 + > UV/PS > PS > UV. Furthermore, higher catechol degradation was observed with increasing iron dosage and PS...
Enhanced Activity of Pr6O11 and CuO Infiltrated Ce0.9Gd0.1O2 Based Composite Oxygen Electrodes
, Article Journal of the Electrochemical Society ; Volume 167, Issue 2 , January , 2020 ; Faghihi Sani, M. A ; Tong, X ; Chen, M ; Hendriksen, P. V ; Sharif University of Technology
Institute of Physics Publishing
2020
Abstract
Operation of solid oxide fuel/electrolysis cells (SOFC/SOEC) at high temperatures (T > 850 °C) is accompanied by degradation phenomena, which severely affect the operational lifetime of the cell. Degradation processes are expected to occur slower at low temperatures. However, significant reduction in electrocatalytic activity of the oxygen electrode, is one of the major challenges in decreasing the operating temperature down to 500 °C-650 °C. Recently, Pr6O11 infiltrated Ce0.9Gd0.1O2 (CGO) based electrodes have been proposed to realize high electrochemical performance at intermediate temperature. In this study, Pr-oxide has been infiltrated into a well performing sub-micro...
Thermo-oxidative degradation during sintering of polyethylene particles
, Article Journal of Applied Polymer Science ; Volume 138, Issue 19 , 2021 ; 00218995 (ISSN) ; Pircheraghi, G ; Sharif University of Technology
John Wiley and Sons Inc
2021
Abstract
Polymer sintering is not only a well-established procedure for producing functional polymeric parts, but it is also the basis for the relatively new additive manufacturing technique, selective laser sintering. Although studying the impact of thermo-oxidative degradation during sintering has significant practical importance, few studies have focused on this aspect of the sintering process. In the present work, we have investigated the active thermo-oxidative degradation mechanisms during sintering of high-density polyethylene (HDPE) particles, the conditions that promote them, and their respective impact on the morphological evolution of the polyethylene particles. To perform a comprehensive...
Mn-doped ZrO2 nanoparticles as an efficient catalyst for green oxidative degradation of methylene blue
,
Article
Catalysis Communications
;
Volume 72
,
2015
,
Pages 1-5
;
15667367 (ISSN)
; Amini, M
; Boghaei, D. M
; Chae, K. H
; Gautam, S
;
Sharif University of Technology
Abstract
Manganese doped on cubic phase nanoparticles of ZrO2 was synthesized by an impregnation method. These novel particles were carefully analyzed by various chemico-physical methods. The catalytic degradation of an organic dye, methylene blue, in the presence of Mn-doped ZrO2 nanoparticles, as well as ZrO2 nanoparticles as catalyst with aqueous hydrogen peroxide, H2 O2 , as an oxidizing agent has been studied in aqueous solution at room temperature. Effects of solution pH, catalyst composition and radical scavenging agents on the degree of degradation of methylene blue were also studied. Finally, the recoverability and reusability of the...
Copper oxide-carbon nanotube (CuO/CNT) nanocomposite: Synthesis and photocatalytic dye degradation from colored textile wastewater
, Article Fibers and Polymers ; Volume 17, Issue 11 , 2016 , Pages 1842-1848 ; 12299197 (ISSN) ; Rezaei, P ; Ghotbei, C ; Kazemeini, M ; Sharif University of Technology
Korean Fiber Society
2016
Abstract
In this paper, CuO/CNT nanocomposite was synthesized and its photocatalytic dye degradation ability for colored textile wastewater was studied. The characteristics of the nanocomposite were investigated by XRD, SEM and FTIR. The photodegradation of Direct Red 31 (DR31) and Reactive Red 120 (RR120) by CuO/CNT in presence of H2O2 was investigated. Photocatalytic dye degradation was determined by UV-vis spectrophotometer. Effects of catalyst dosage, initial dye concentration and salt on photodegradation performance were studied. The photocatalytic dye degradation ability of pure CuO and CuO/CNT nanocomposite is 78 % and 89 % for DR31 and 70 % and 87 % for RR120, respectively. The results showed...
Synthesis and characterization of photocatalytically active crumpled-shape nanocomposites of nitrogen and sulfur co-doped ZnO–CeO2
, Article Solar Energy Materials and Solar Cells ; Volume 203 , 2019 ; 09270248 (ISSN) ; Sabour Rouh Aghdam, A ; Nazari, M ; Bayat, A ; Saievar Iranizad, E ; Najafi Liavali, M ; Sharif University of Technology
Elsevier B.V
2019
Abstract
In this study, crumpled-shape nanocomposite of nitrogen and sulfur co-doped ZnO–CeO2 (NSZC) was deposited on FTO substrate using one-step ultrasonic spray pyrolysis. Zinc acetate, cerium nitrate, and thiourea were dissolved in deionized water and used as starting solution. The samples were characterized using FESEM, XRD, UV–vis spectroscopy, EIS, and PL. The as-prepared nitrogen and sulfur co-doped ZnO–CeO2 nanocomposites were evaluated as high photocatalysts for degradation of methyl orange. Nearly 100% photocatalytic degradation of methyl orange was achieved for 180 min. The photoluminescence and electrochemical impedance spectroscopy revealed that co-doping of nitrogen and sulfur could...
Efficient Fe/CuFeO2/rGO nanocomposite catalyst for electro-Fenton degradation of organic pollutant: Preparation, characterization and optimization
, Article Applied Organometallic Chemistry ; Volume 33, Issue 10 , 2019 ; 02682605 (ISSN) ; Rahman Setayesh, S ; Sharif University of Technology
John Wiley and Sons Ltd
2019
Abstract
The nanocomposite of zero-valent iron and delafossite CuFeO2 supported on reduced graphene oxide was synthesized for the first time to evaluate its performance as the heterogeneous catalyst toward electro-Fenton (EF) removal of catechol. X-ray diffraction, Fourier transform-infrared, scanning electron microscopy and Brunauer–Emmett–Teller (BET) were used to characterize the nanocomposite. It was found that the rhombohedral structure of CuFeO2 remained stable during the nanocomposite preparation. The BET surface area of the nanocomposite increased about 102 times in comparison with bare CuFeO2. The influence of the operating parameters was investigated. The optimum operating conditions were...
Vanadium supported on spinel cobalt ferrite nanoparticles as an efficient and magnetically recoverable catalyst for oxidative degradation of methylene blue
, Article Applied Organometallic Chemistry ; Volume 33, Issue 10 , 2019 ; 02682605 (ISSN) ; Amini, M ; Bagherzadeh, M ; Hosseini, H ; Sharif University of Technology
John Wiley and Sons Ltd
2019
Abstract
Vanadium supported on spinel cobalt ferrite nanoparticles was synthesized and characterized using Fourier transform infrared spectroscopy, X-ray diffraction, energy-dispersive X-ray analysis and transmission electron microscopy. For the first time, the prepared material was used for the catalytic degradation of methylene blue as an organic dye in the presence of hydrogen peroxide as a green oxidant and NaHCO3 as a co-reagent at room temperature. The dependency of removal percentage on various parameters such as amount of catalyst, pH, reaction time and temperature and the effect of radical scavenging agents were studied. Finally, recoverability and reusability of the vanadium supported on...
Thermo-oxidative degradation during sintering of polyethylene particles
, Article Journal of Applied Polymer Science ; 2020 ; Pircheraghi, G ; Sharif University of Technology
John Wiley and Sons Inc
2020
Abstract
Polymer sintering is not only a well-established procedure for producing functional polymeric parts, but it is also the basis for the relatively new additive manufacturing technique, selective laser sintering. Although studying the impact of thermo-oxidative degradation during sintering has significant practical importance, few studies have focused on this aspect of the sintering process. In the present work, we have investigated the active thermo-oxidative degradation mechanisms during sintering of high-density polyethylene (HDPE) particles, the conditions that promote them, and their respective impact on the morphological evolution of the polyethylene particles. To perform a comprehensive...
Tuning composition of electrospun ZnO/CuO nanofibers: toward controllable and efficient solar photocatalytic degradation of organic pollutants
, Article Journal of Physical Chemistry C ; Volume 121, Issue 6 , 2017 , Pages 3327-3338 ; 19327447 (ISSN) ; Samadi, M ; Mahmoodi, N. M ; Pourjavadi, A ; Mehdipour, H ; Moshfegh, A. Z ; Sharif University of Technology
American Chemical Society
2017
Abstract
ZnO/CuO nanofibers, with different CuO concentrations, were fabricated by one-step electrospinning of the polymer precursor and annealing in air. Scanning electron microscopy (SEM) showed smooth and beadless morphology for the synthesized nanofibers, while X-ray diffraction (XRD) analysis revealed formation of hexagonal and monoclinic crystalline structure phases for ZnO and CuO nanofibers, respectively. X-ray photoelectron spectroscopy (XPS) analysis confirmed the presence of CuO on the surface of ZnO nanofibers. For further confirming the formation of chemical bonds, Fourier transform infrared (FT-IR) spectroscopy was employed. The effect of Cu contents in the overall electronic band...
Efficient and green oxidative degradation of methylene blue using Mn-doped ZnO nanoparticles (Zn1−x Mnx O)
,
Article
Journal of Experimental Nanoscience
;
Volume 10, Issue 16
,
2015
,
Pages 1256-1268
;
17458080 (ISSN)
; Amini, M
; Boghaei, D. M
;
Sharif University of Technology
Taylor and Francis Ltd
2015
Abstract
Mn-doped ZnO nanoparticles, Zn1−x Mnx O, were synthesised by a polyethylene glycol (PEG) sol–gel method and the physicochemical properties of compounds were characterised by atomic absorption spectroscopy (AAS), energy-dispersive X-ray analysis, X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The catalytic degradation of an organic dye, methylene blue (MB), in the presence of Zn1−x Mnx O as the catalyst and hydrogen peroxide (H2 O2 ) as the oxidant at room temperature in water has been studied. Effects of oxidant, catalyst amount, catalyst composition, pH value of the solution and an OH-radical...