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surface-modification
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Removal of fluoride from wastewater by natural and modified nano clinoptilolite zeolite
, Article Journal of Water and Environmental Nanotechnology ; Volume 5, Issue 3 , 2020 , Pages 270-282 ; Charkhi, A ; Kazemeini, M ; Yousefi, T ; Sharif University of Technology
Iranian Environmental Mutagen Society
2020
Abstract
In this study adsorption of fluoride ion from high-fluorine solutions (<2000 ppm) using the natural and modified ground clinoptilolite is investigated. These low-cost adsorbents are carefully characterized by scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray fluorescence (XRF), thermos-gravimetry (TGA) and differential scanning calorimeter analysis (DSC). In order to enhance the fluoride removal capacity of natural zeolite, it is milled into nano-powders and modified using hexadecyltriammoniumions (HDTMA+). The kinetic, equilibrium, and thermodynamic of fluoride adsorption are measured and described by the well-known...
Simultaneous dual-functional photocatalysis by g-C3N4-based nanostructures
, Article ACS ES and T Engineering ; Volume 2, Issue 4 , 2022 , Pages 564-585 ; 26900645 (ISSN) ; Zaker Moshfegh, A ; Habibi Yangjeh, A ; Sillanpää, M ; Sharif University of Technology
American Chemical Society
2022
Abstract
Heterogeneous photocatalytic reactions have experienced many efforts in developing new materials to tackle environmental and energy crises through utilizing appropriate photocatalysts in wastewater treatment, H2 generation, organic transformations, CO2 reduction, N2 photofixation, and biomass conversion. While these processes are addressed in the literature separately, a recent innovative viewpoint is to employ a photocatalytic system to achieve simultaneously two or more functions. The challenging point is that the combination of two functions in one photocatalytic system requires a novel design and engineering of an appropriate semiconductor photocatalyst with special characteristics for...
Effect of CO2-laser irradiation on properties and performance of thin-film composite polyamide reverse osmosis membrane
, Article Korean Journal of Chemical Engineering ; Volume 33, Issue 3 , 2016 , Pages 1028-1036 ; 02561115 (ISSN) ; Mousavi, S. A ; Farhadi, F ; Vatanpour, V ; Sabzi, B ; Chenari, Z ; Sharif University of Technology
Springer New York LLC
2016
Abstract
CO2-laser irradiation was used to modify the surface properties of thin-film composite (TFC) polyamide reverse osmosis (RO) membranes. These membranes were first synthesized via interfacial polymerization of m-phenylenediamine (MPD) monomers and trimesoyl chloride (TMC) over porous polysulfone ultrafiltration support, followed by a CO2-irradiation. AFM, ATR-FTIR, SEM and contact angle measurements were used to characterize the surface properties of these membranes. The ATR-FTIR results indicated that CO2-laser irradiation did not induce any functional groups on the membrane surface. However, it was found that the laser irradiation enhanced the NaCl salt rejection and slightly reduced the...
Synthesis of Silica Nanoparticles Modified with Alumina and Its Performance in Compressive Strength of Concrete
, M.Sc. Thesis Sharif University of Technology ; Sajadi, Ali Akbar (Supervisor) ; Ghanbari, Bahram (Supervisor)
Abstract
Silica nanoparticles is one of the most important mineral particles. In this study, Sodium silicate, Sulfuric acid and Sodium aluminate is used in order to synthesis of the modified Silica nanoparticles. The effects of temperature, reaction time and the molar ratio of regents were tested and optimized. Synthesized nanoparticles were characterized by use of XRD, FT-IR and SEM techniques. The results show that by controlling the reaction conditions, nanoparticles with an average size of 26.2 nm is obtained. The increase of temperature and reaction time alters the structure of the particles of amorphous state to a crystalline needles. The particle surface modification process was performed by...
A study on the concentration-dependent relaxometric transition in manganese oxide nanocolloid as mri contrast agent
, Article ChemistrySelect ; Volume 4, Issue 25 , 2019 , Pages 7596-7601 ; 23656549 (ISSN) ; Malek, M ; Hosseini, H. R. M ; Delavari H, H ; Vahdatkhah, P ; Sharif University of Technology
Wiley-Blackwell
2019
Abstract
A green precipitation method has been used for the synthesis of ultra-small APTMS-mPEG conjugated Mn3O4 nanoparticles. Spherical cores in the uniform size of 4±1 nm were characterized by HRTEM. Zeta potential of −45 mV and the invariant turbidimetry results during the time, confirmed super-stability of the colloids. MRI relaxometry by 1.5 T scanner represented two values of r1= 8.23 s−1mM−1 and r1=7.3 s−1mM−1 for diluted and concentrated samples. The r2/r1 ratio was also decreased from 11.86 to 6.9 by dilution of colloids. Particle aggregation and motional narrowing phenomena led to a dual T1/T2 contrast agent in the Mn ion concentrations of more than 0.2 mM. The optimum concentration of Mn...
Polymer matrix nanocomposites for heavy metal adsorption: a review
, Article Journal of the Iranian Chemical Society ; Volume 17, Issue 6 , 31 January , 2020 , Pages 1259-1281 ; Keikavousi Behbahan, A ; Sharif University of Technology
Springer
2020
Abstract
Heavy metals belong to a group of lethal environmental pollutants. Ongoing efforts targeted at safeguarding public health have led to considerable attention being focused on methods that allow efficient extraction of these toxic substances. Polymer nanocomposites (PNCs) with their special characteristics are a class of adsorbents that demonstrate high potential for use in heavy metal extraction. As this process of removal is predominantly governed by adsorption, various parameters in PNCs’ chemical structure, as well as the metal solutions, can have a significant effect on the adsorption process. Herein, this review undertakes a survey of recently developed PNCs and their metal adsorption...
Photocatalytic reforming of biomass-derived feedstock to hydrogen production
, Article Research on Chemical Intermediates ; Volume 48, Issue 5 , 2022 , Pages 1793-1811 ; 09226168 (ISSN) ; Naseri, A ; Abdollahi, N ; Samadi, M ; Moshfegh, A ; Sharif University of Technology
Springer Science and Business Media B.V
2022
Abstract
Worldwide energy and environmental issues are forcing researchers to develop a green approach to produce a clean energy. However, traditional methods in reforming of fossil fuels to produce hydrogen (H2) are causing CO2 emission. Hydrogen is therefore an indirect greenhouse gas with a global warming potential. Hydrogen with high specific energy density can be considered as an efficient energy carrier as compared to fossil fuels. But hydrogen production from water splitting reaction has low efficiency, which limits its generation by green approach. For addressing this issue, different chemical hole scavengers have been applied, which is causing further environmental and economic problems. By...
Effectively exerting the reinforcement of polyvinyl alcohol nanocomposite hydrogel via poly(dopamine) functionalized graphene oxide
, Article Composites Science and Technology ; Volume 217 , 2022 ; 02663538 (ISSN) ; Pircheraghi, G ; Nazockdast, H ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
Nature-inspired coating with polydopamine (PDA) is a promising way to improve the performance of graphene oxide (GO) based nanocomposites due to its high ability to enhance interactions in matrix-disperse systems. Here, we examined the capability of two types of PDA to develop the reinforced polyvinyl alcohol (PVA)/GO hydrogels. In the first mode, dopamine hydrochloride was polymerized as nanoparticles and then incorporated into PVA solution with GO nanoplatelets (P-NG hydrogel). In the second mode, polydopamine was polymerized in the presence of GO nanoparticles to obtain PDA surface-modified GO and then PVA nanocomposite hydrogel (P-CG sample). Rheological and tensile findings revealed...
Surface Modification of Polyethersulfone Membrane by Plasma Treatment for Gas Separation
, M.Sc. Thesis Sharif University of Technology ; Soltanieh, Mohammad (Supervisor)
Abstract
In this study, the effects of treatment time and power of Low-frequency (LF) O2 plasma has been investigated for the surface treatment of polyethersulfone (PES) gas separation membranes. PES membranes prepared using dry/wet phase inversion using ternary mixtures containing 1-methyl-2-pyrrolidone (NMP) as solvent, water as non-solvent. The optimum polymer concentration was 32 wt.% , 61 wt.% and 7 wt.% for PES,1-methyl-2-pyrrolidone and water respectively. Pure CO2 and CH4 gas permeation measurements were performed before and after plasma treatment. After treatment gas permeances of around 0.81 GPU for CO2, and 0.073 GPU for CH4 with selectivities of around 11.23 for CO2/CH4 were obtained....
Adsorption of Heavy Metals and Various Pollution from Aqueous Solutions by Vegetable Residues
, M.Sc. Thesis Sharif University of Technology ; Bastani, Dariush (Supervisor) ; Seif-Kordi, Ali Akbar (Supervisor)
Abstract
Celery residue modified with H2SO4 was utilized as a low-cost adsorbent for removal of hazardous dyes (methylene blue, malachite green and congo red) and heavy metals (Pb(II) and Cd(II)) from aqueous solution in batch adsorption process. Also, celery residue modified with cationic surfactant (CTAB) to enhance the removal of congo red (anionic dye). The treated and untreated adsorbent was characterized by Fourier transform infrared (FTIR) spectroscopy and Scanning Electron Microscopy (SEM). The efficacy of dye removal of the modified celery residue was investigated by varying adsorbent dose, contact time, pH, initial dye concentration, and temperature. Experimental data were fitted by three...
Improve Performance of Polyamide Reverse Osmosis Membranes by Crosslinking Treatments
, M.Sc. Thesis Sharif University of Technology ; Mousavi, Abbas (Supervisor)
Abstract
Reverse osmosis membranes are one of the most common methods of desalination of water in the world today. In the meantime, aromatic polyamide thin-film composite reverse osmosis membranes have one of the best performances and can be widely used in industry. This project aims to make surface modifications on the made raw membranes and increase the degree of crosslinking to improve the functional properties of the membrane, such as the percentage of salt rejection and the flux of permeate, and the reduction of fouling. For this purpose, polyvinyl alcohol and l-arginine along with maleic anhydride as the crosslinking agent and hexamethylene diisocyanate were used for surface modification of the...
Surface Modification of Polysulfone Membrane by Plasma Treatment for CO2/CH4 Separation
, M.Sc. Thesis Sharif University of Technology ; Soltanieh, Mohammad (Supervisor)
Abstract
Low frequency (LF) O2 plasma was used to modify the surface of polysulfone (PSF) gas separation membranes. The effect of treatment time and plasma power input on the membranes was also investigated. Pure CO2 and CH4 gas permeation measurements were performed before and after plasma treatment. The results showed the increase of permeability of the treated membranes due to surface ablation and surface polarization. However, the CO2/CH4 permselectivity of the treated membranes varied from 7.7 to 45.3 depending on the treatment conditions. Attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy determined the introduction of oxygen containing polar groups on the surface...
Surface Modification of Hemodialysis Membrane for Enhancement of Their Performance
, M.Sc. Thesis Sharif University of Technology ; MoosavI, Abbas (Supervisor) ; Abdekhodaie, Mohammad Jafar (Supervisor)
Abstract
A new technique for surface modification of flat sheet hemodialysis membranes has been investigated. This new strategy presents a dynamic surface modification for membranes in order to assess the hydrophilicity, antifouling, and biocompatibility effects of two functional monomers on dialysis membrane. PSF membranes containing polyvinylpyrrolidone were prepared via phase inversion technique. Afterward, free radical polymerization combined with surface polymerization used to introduce acrylic acid and 2-hydroxyethyl methacrylate onto polysulfone membrane surface. Various monomer concentrations were selected to obtain an optimum condition. Field emission scanning electron microscope (FE-SEM),...
The Role of Surface Functionalization of Nanodiamond on the Vulcanization Kinetics and Network Structure of SBR
, M.Sc. Thesis Sharif University of Technology ; Shojaie, Akbar (Supervisor)
Abstract
Elastomers are flexible polymers with various uses in different industries. But this materials dont havevalid usages without correct fillers. Today Nano technology has a main role in the industry. one of the important reasons is rubber quality improvement with adding just a little amount of this clays, opposite to Carbon Black. To achieve a high quality polymer composite, it is necessary to learn about physical and mechanical properties of nano clays and the interaction between Nano clays and matrix. Because of the effect of nano clays on vulcanization, this issue is noticeable . Nano diamond is a nanoclay used to improve rubber quality. But this method is new because of the complicated...
Preparation and Characterization of Inhibitor Loaded Nanodiamond for Anticorrosion Coating
, M.Sc. Thesis Sharif University of Technology ; Shojaei, Akbar (Supervisor) ; Pirhadi, Nahid (Co-Supervisor)
Abstract
In recent years, nanodiamond (ND) has been used as reinforcement in polymeric nanocomposites in order to improve mechanical properties, thermal conductivity, etc. The surface of nanodiamond has several functional groups which make it appropriate adsorbent. In this study, nanodiamond was modified with dodecylamine corrosion inhibitor and was utilized (1wt %) in epoxy based nanocomposite. Fourier transform infrared spectroscopy (FTIR) analysis was used to confirm the surface modification of Nanodiamond. In order to estimate the loading amount of corrosion inhibitor, thermogravimetric analysis was investigated. FE-SEM analysis demonstrated nanoparticle dispersibility in epoxy matrix. Regarding...
The Impact of Temperature on Surface Activity and Stability of Surface Modified Nano Particles
, M.Sc. Thesis Sharif University of Technology ; Mohammadi, Ali Asghar (Supervisor)
Abstract
Surface modification is an important property of nano particles. In this project surface of silica nano particles modified with hydrophobic and hydrophilic groups to imrprove surface activity of nano particles. Purpose of this project is to study surface activity of surface modified silica nano particles in different temperatures from 20 to 70 degree centigrade. Also effect of salt and time on the surface activity is studied. At first nano particles modified just with haydrophobic groups and then just with hydrophilic groups (hydrophobic and hydrophilic nano particles) and after that, the surface modification done with both hyadrophilic and hydrophobic groups (amphiphilic nanoparticles)....
Janus Silica Nanoparticles and Their Application for Enhanced Oil Recovery
, M.Sc. Thesis Sharif University of Technology ; Mohammadi, Ali Asghar (Supervisor)
Abstract
Nanoparticles can be applied as chemical agent in enhnaced oil recovery like surfactants and polymers. One of nanoparticles usefull capabilities is modification of their surface. This research investigates this capabilty of nanoparticles in enhanced oil recovery. Surface modification of nanoparticles with both agents can bring new abilities to these materials. Here surface of silica nanoparticles is modified by hydrophilic agent comprising PEG groups, hydrophobic agent comprising propyl group and both agents. FT-IR tests showed that grafting of modifiyng agents on surface of nanoparticles is well done. To investigate effect of nanoparticles surface modification on nanoparticles capability in...
UF Polymeric Membranes Modification with Chemical Method for Enhancement of Their Performance
, M.Sc. Thesis Sharif University of Technology ; Bastani, Daruoosh (Supervisor) ; Mousavi, Ali (Supervisor)
Abstract
In this research, modification of polysolfune ultrafiltration membranes is investigated. The enhancement is done via grafting of the acrylic acid as a hydrophilic monomer on the membrane surface. This is a free radical grafting method in which free radicals are formed via redox reaction of ammonium persulfate and sodium metabisulfite as an initiator. Water contact angle, molecular weight cut-off, pure water flux and fouling experiments were used to figure out the optimum conditions for the membrane performance. In addition, scanning electron microscopy (SEM) and atomic force microscopy (AFM) were utilized to determine morphological changes of the membrane surface. Furthermore, Fourier...
Fabrication and Thermal Analysis of Superhydrophobic Nano-textured Condensation Substrates
, M.Sc. Thesis Sharif University of Technology ; Mousavi, Ali (Supervisor) ; Asghari, Mohsen (Supervisor)
Abstract
This thesis is a research corresponding to Super-Hydrophobic condensation substrates with Nanometer texture. In this study, the foresaid surfaces are fabricated by two methods that are Nano-composite paint and Electrophoretic coating. As a summary for the first method (the Super-Hydrophobic Nano-composite paint), the hybrid coating contains two mineral and organic phases; The organic phase is a two-part clear-coat polyurethane and plays the role as a polymer matrix in Nano-composite structure. Silica Nano-particles are the mineral phase and the two phases of Nano-composite have made connection with silane compounds. Also, surface-modification in Nano-particles for giving hydrophobicity...
Investigating the Effect of Nanosilica Functionalized with Silane in Concrete Mortar on the Corrosion Behavior of Reinforcement
, M.Sc. Thesis Sharif University of Technology ; Dolati, Abolqasem (Supervisor)
Abstract
The aim of this project is to investigate the effect of adding nano-silica on reinforcement corrosion in concrete caused by chloride. Because concrete is a porous composite, which is exposed to a corrosive environment such as the sea, it needs more protection to control the corrosion of steel reinforcement. This has led to the necessity of using nanoparticles in concrete mortar. This research was done by evaluating the effect of adding nanosilica gel as a partial replacement of type 2 Portland cement and hydrophobic nanosilica, respectively, to mortar and concrete surface on the corrosion resistance of reinforcement. In the project, three models of concrete samples with a cement grade of 550...