Search for: degradation
Total 375 records
Removal of an organic pollutant from waste water by photocatalytic behavior of AgX/TiO2 loaded on mordenite nanocrystals, Article Research on Chemical Intermediates ; Volume 38, Issue 8 , 01 September , 2012 , pp 1975-1985 ; 1568-5675 ; Salari, H. (Hadi) ; Ahmadvand, S. (Seyed Saeid) ; Gholami, M. R. (Mohammad Reza) ; Sharif University of Technology
Mordenite (MOR) nanocrystals were synthesized using the hydrothermal method. Sol–gel and deposition methods were utilized to modify the zeolite surface with TiO2 and then AgBr or AgCl particles. Photocatalysts were characterized by using X-ray diffraction, Brunauer–Emmett–Teller (BET), and scanning electron microscopy techniques. Activity was evaluated by photodegradation of Acid Blue 92 as an azo dye. The effect of silver halide deposition on the photocatalytic behavior of the prepared nanocomposites was studied under both ultraviolet (UV) and visible light, and the results were compared. The results showed that AgCl/TiO2/MOR was more active under UV, while with visible source,...
Degradation based optimization framework for long term applications of energy systems, case study: Solid oxide fuel cell stacks, Article Energy ; Volume 107 , 2016 , Pages 172-181 ; 03605442 (ISSN) ; Parhizkar, T ; Sharif University of Technology
Elsevier Ltd 2016
Depletion of fossil fuels has increased the pressure on energy systems to operate in the most efficient and economical mode. This tendency promotes energy systems to operate at optimum operating conditions, which maximizes the system profit over lifetime. Recently, there have been many attempts to maximize lifetime profit. Most of them concentrate on the power generation aspect without incorporating further aspects such as system degradation and profitability through lifetime. However, the main intention of the system operators is to optimize the profitability of system at the moment of operation and not the total profitability through the system lifetime. In this study a novel approach is...
Effective photocatalytic degradation of an azo dye over nanosized Ag/AgBr-modified TiO2 loaded on zeolite, Article Journal Chemical Papers ; Volume 65, Issue 3 , June , 2011 , pp 280-288 ; 1336-9075 ; Tasviri, M. (Mahboubeh) ; Gholami, M. R. (Mohammad Reza) ; Sharif University Of Technology
Zeolite-based photocatalysts were prepared by the sol-gel and deposition methods. The photocatalysts were characterised by X-ray diffraction, nitrogen adsorption-desorption isotherms, FTIR spectroscopy, scanning electron microscopy and energy-dispersive X-ray spectrometry. The activity of the prepared photocatalysts was evaluated by the UV-induced degradation of acid blue 92, a textile dye in common use. The effect of various parameters, such as catalyst concentration, initial dye concentration, thiosulphate concentration and pH, on the rate and efficiency of the photocatalytic degradation of acid blue 92 was investigated. The results showed that each parameter influenced the degradation...
Article Engineering Failure Analysis ; 2010 ; 13506307 (ISSN) ; Abouali, S ; Akbari Garakani, M
Article Engineering Failure Analysis ; 13506307 (ISSN) ; Abouali, S ; Akbari Garakani, M ; Sharif University of Technology
Article Desalination and Water Treatment ; Volume 57, Issue 58 , 2016 , Pages 28450-28459 ; 19443994 (ISSN) ; Sadrnezhaad, S. K ; Sharif University of Technology
Taylor and Francis Inc 2016
In this work, the effect of addition of ZrO2 to TiO2 and catalyst geometry on photocatalytic properties of the nanocomposite TiO2/ZrO2 was investigated. The traditional use of powdery photocatalyst for the degradation of organic compounds has post-treatment problems which means much higher time and costs. A novel method to minimize these problems is immobilization by insertion onto an inert substrate. Several geometries of TiO2–10%ZrO2 (T-10Z) nano-photocatalysts (powder, fiber, film, and network-shaped) were produced using different templates. The products were characterized by X-ray diffraction, field emission scanning electron microscopy, Brunauer–Emmett–Teller, and diffuse reflectance...
The photoinduced activity of Ni-TiO2/TiO2 multilayer nanocomposites synthesized by pulse electrodeposition technique, Article International Journal of Electrochemical Science ; Volume 12, Issue 6 , 2017 , Pages 5121-5141 ; 14523981 (ISSN) ; Dolati, A ; Ghorbani, M ; Sharif University of Technology
The sol-enhanced pulse plating (PP) technique was utilized to deposit the Ni-TiO2/TiO2 multilayers on copper substrates from a Watts bath containing a TiO2 sol, and the obtained coatings were heat treated at various temperatures. The characteristics of coatings were examined using scanning electron microscopy (SEM), X-ray diffraction (XRD), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and UV-visible spectrophotometry. In order to estimate the wettability of these nanostructured multilayers after exposure to UV light, the contact angle of water droplets were measured, and the photocatalytic (PC) efficiency of the multilayers were analyzed by the degradation of methyl...
Investigation of 2-nitrophenol solar degradation in the simultaneous presence of K2S2O8 and H2O2: Using experimental design and artificial neural network, Article Journal of Cleaner Production ; Volume 176 , 2018 , Pages 1154-1162 ; 09596526 (ISSN) ; Feylizadeh, M. R ; Delparish, A ; Qanbarzadeh, M ; Raeiszadeh, M ; Feilizadeh, M ; Sharif University of Technology
Elsevier Ltd 2018
In this study, the interaction effect of K2S2O8 (PDS) and H2O2 (as two powerful oxidants) was investigated on the solar degradation of 2-nitrophenol (2-NF) in the two systems, i.e. absence and presence of Ag/S/TiO2 photocatalyst. Experiments were designed based on the central composite design, and two methods of response surface methodology (RSM) and artificial neural network (ANN) were developed for modeling of the systems. Concentrations of PDS and H2O2 were considered as independent variables and 2-NF degradation efficiency was selected as the response. It was revealed that the predictive capacity of ANN model is more than RSM model according to their corresponding R2, R2 adj RMS, MAE,...
In-situ formation and entrapment of Ag/AgCl photocatalyst inside cross-linked carboxymethyl cellulose beads: A novel photoactive hydrogel for visible-light-induced photocatalysis, Article Journal of Photochemistry and Photobiology A: Chemistry ; Volume 398 , 2020 ; Golizadeh, M ; Padervand, M ; Karimi, A ; Vossoughi, M ; Tavakoli, M. H ; Sharif University of Technology
Elsevier B.V 2020
In this work, a novel photoactive cellulose-based hydrogel was prepared by simultaneous AgCl formation and entrapment inside Al (III) and Fe (III) cross-linked carboxymethyl cellulose beads. Physio-chemical and optical properties of the synthesized composites were well characterized by X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM), energy dispersive X-ray (EDX) analysis, elemental mapping, Fourier transform infrared (FTIR) spectroscopy, photoluminescence (PL), and diffuse reflectance spectroscopy (DRS). The photocatalytic activity of hydrogels was evaluated by the degradation of rhodamine B (RhB), as a model environmental pollutant. A comparative study showed that...
Article Materials and Design ; Volume 26, Issue 1 , 2005 , Pages 89-93 ; 02613069 (ISSN) ; Mousavi, S ; Sharif University of Technology
Elsevier Ltd 2005
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...
Thermal degradation behavior and kinetic analysis of ultra high molecular weight polyethylene based multi-walled carbon nanotube nanocomposites prepared via in-situ polymerization, Article Journal of Macromolecular Science, Part A: Pure and Applied Chemistry ; Volume 49, Issue 9 , 2012 , Pages 749-757 ; 10601325 (ISSN) ; Saadatabadi, A. R ; Khorasheh, F ; Sharif University of Technology
Thermal degradation behavior of multi-wall carbon nanotubes (MWCNTs)/ultra high molecular weight polyethylene (UHMWPE) nanocomposites, with different nanotubes contents (0.5, 1.5 and 3.5 wt%) prepared via in-situ polymerization technique have been investigated using thermal gravimetric analysis (TGA). TGA spectra revealed that these nanocomposites had enhanced thermal stability and no significant mass loss (<0.4 wt%) occurred up to 350°C. Thermal degradation of these UHMWPE/MWCNT nanocomposites was investigated in terms of parameters such as the onset temperature of degradation (T 10), the decomposition temperature at 50% wt loss (T 50), the degradation temperature of maximum rate of the...
Numerical study of Geostationary Orbit thermal cycle effects of a tubular adhesive joint: Dynamic behavior, Article Journal of Adhesion ; Volume 96, Issue 16 , 2020 , Pages 1431-1448 ; Mokhtari, M ; Sharif University of Technology
Bellwether Publishing, Ltd 2020
Space environments have a significant influence on advanced composite structures and adhesive joints. Degradation in the mechanical properties of aerospace materials changes the dynamic behavior of the structures and adhesive joints. In this paper, a typical tubular adhesive joint with material degradation due to geostationary orbit (GEO) thermal cycles has been studied numerically with Python scripts. Adhesive joint geometry and boundary conditions are the main parametric study parameters. The results show that the first non–zero natural frequencies of the clamped-free tubular adhesive joint decreased due to mechanical property degradation. A dynamic behavior comparison of the degradation...
Sonophotocatalytic degradation of sulfadiazine by integration of microfibrillated carboxymethyl cellulose with Zn-Cu-Mg mixed metal hydroxide/g-C3N4 composite, Article Separation and Purification Technology ; Volume 245 , 2020 ; Khataee, A ; Vahid, B ; Karimi, A ; Golizadeh, M ; Ritala, M ; Sharif University of Technology
Elsevier B.V 2020
This research aimed to prepare a recoverable sonophotocatalyst, in which microfibrillated carboxymethyl cellulose (MFC) acted as the Zn-Cu-Mg-mixed metal hydroxide/graphitic carbon nitride (MMH/g-C3N4) carrier. The characteristics of bare and composite sonophotocatalysts were analyzed by the XRD, FT-IR, BET, DRS, PL and FE-SEM equipped with the EDX mapping. The performance of prepared composites (MMH/g-C3N4@MFC) with various weight ratios of the MMH/g-C3N4 was studied for the sonophotocatalytic degradation of sulfadiazine (SDZ) as the model emerging contaminant. 93% of SDZ was degraded using the most effective catalyst (MMH/g-C3N4@MFC3) with 15% weight ratio of the MMH/g-C3N4 under the...
Integrated system of multiple batches to evaluate the continuous performance of microbial cells in decolourization processes, Article Journal of Environmental Chemical Engineering ; Volume 6, Issue 1 , February , 2018 , Pages 728-735 ; 22133437 (ISSN) ; Bagheri Lotfabad, T ; Heidarinasab, A ; Ebadipour, N ; Yaghmaei, S ; Sharif University of Technology
Elsevier Ltd 2018
Azo dye degradation in wastewater treatment is a subject which has garnered the attention of many research studies. In this study, an innovative approach, namely, an integrated system of five batches (ISFB), was developed to investigate the capability of Saccharomyces cerevisiae ATCC 9763 for continuous degradation of methyl red as a representative azo dye. Toward this end, an expanded immobilized microbial bed (EIMB) reactor was established with a bed of encapsulated yeast cells in sodium alginate. EIMB reactor was run in two modes, single batch and ISFB. Moreover, durability of the microbial cells was evaluated by repeating the continuous decolourization eight sequential times in EIMB at...
Comparing the efficacy of catalytic ozonation and photocatalytical degradation of cyanide in industrial wastewater using ACF-TiO2: catalyst characterisation, degradation kinetics, and degradation mechanism, Article International Journal of Environmental Analytical Chemistry ; 18 May , 2020 ; Hassani, A. H ; Torabian, A ; Borghei, S. M ; Sharif University of Technology
Taylor and Francis Ltd 2020
In the present study, the ACF-TiO2 catalyst was synthesised and used as a catalyst for the destruction of toxic cyanide in both synthetic and real industrial wastewaters. The ACF-TiO2 catalyst was found to be micro-porous with the BET surface area of 163 m2/g. The effect of different operational parameters such as catalyst concentration, cyanide concentration, operation time, and ozone concentration were target parameters in the present study. The findings show that 500 mg/L of catalyst is the optimum value for the photocatalytical process to completely oxidise 25 mg/L of cyanide within 10 min. While it was found that 300 mg/L of catalyst in the presence of 200 mg/h ozone is enough to remove...
Article Smart Innovation, Systems and Technologies, 3 September 2019 through 5 September 2019 ; Volume 166 , 2020 , Pages 855-869 ; Behzad, M ; Mirfarah, M ; Sharif University of Technology
Springer Science and Business Media Deutschland GmbH 2020
Predicting the residual-life (RL) of rolling element bearings (REBs) is an essential procedure of rotating machinery condition monitoring, in industries. Since the bearing fault propagation has a complicated stochastic nature, the multi-phase phenomenon is probable to happen in the degradation process. By occurrence of the multi-phase phenomenon, the degradation process experiences different phases, with distinct failure rate in each phase. Therefore, the mentioned phenomenon leads to large error in the prediction results of single-phase degradation models. The main concern of the present paper is to consider the effect of multi-phase phenomenon on the prediction confidence level of REBs. In...
Article Polymers from Renewable Resources ; Volume 11, Issue 1-2 , 2020 , Pages 15-29 ; Gilak Hakimabadi, S ; Nabavi, F ; Vossoughi, M ; Alemzadeh, I ; Sharif University of Technology
SAGE Publications Ltd 2020
In this study, effects of glycerol (10, 20, and 30 wt%) and Sodium Montmorillonite (Na-MMT) (0%, 2.5%, and 5%) contents on the degradation of corn starch polymers were investigated. Films were prepared by casting corn starch solution using a modified method to enhance the nanoclay distribution. Biodegradability studies were performed by enzymatic and burial tests using pristine and enriched soils. The biodegradability of samples in pristine soil was faster, and all samples were fully degraded in 6 months. The effect of nanoparticles on the mass reduction in degradation was more pronounced than that of glycerol. In all glycerol concentrations, Na-MMT addition increased tensile strength. FTIR...
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
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...
Photo-degradation of organic dye by zinc oxide nanosystems with special defect structure: Effect of the morphology and annealing temperature [electronic resource], Article Journal of Applied Catalysis A: General ; 22 February 2014, Volume 472, Pages 198–204 ; Simchi, A. (Abdolreza) ; Ghanbari, Faegheh ; Vossoughi, M ; Sharif University of Technology
The fabrication of strong photocatalysts applied to the degradation of organic pollutants is necessary in environmental applications. In a single-stage method, acetate precursor and poly vinyl pyrolydine are used to produce ZnO nanostructures with various morphologies in annealing temperatures ranging from 300 to 900 °C. The physical properties of the prepared nanostructures were characterized by SEM, TEM, XRD, BET, DRS, CHN analysis and PL spectroscopy. The SEM images exhibit a variety of the as-prepared hexagonal zinc oxides including wires, rods, particles and porous network of welded particles of ZnO nanoparticles. The results of the photocatalytic degradation of methylene blue as an...
Strain rate sensitivity, work hardening, and fracture behavior of an Al-Mg TiO2 nanocomposite prepared by friction stir processing [electronic resource], Article Journal of Metallurgical and Materials Transactions A ; August 2014, Volume 45, Issue 9, P.4073-4088 ; Simchi, A. (Abdolreza) ; Kokabi, Amirhossein ; Nosko, Martin ; Svec, Peter ; Sharif University of Technology
Annealed and wrought AA5052 aluminum alloy was subjected to friction stir processing (FSP) without and with 3 vol pct TiO2 nanoparticles. Microstructural studies by electron backscattered diffraction and transmission electron microscopy showed the formation of an ultra-fine-grained structure with fine distribution of TiO2 nanoparticles in the metal matrix. Nanometric Al3Ti and MgO particles were also observed, revealing in-situ solid-state reactions between Al and Mg with TiO2. Tensile testing at different strain rates determined that FSP decreased the strain rate sensitivity and work hardening of annealed Al-Mg alloy without and with TiO2 nanoparticles, while opposite results were obtained...