Sharif Digital Repository

Catalytic reduction of nitrobenzene is the leading technological step in aniline production. The hydrogen required for this stage, is dominantly produced from fossil fuels through reforming processes, which take much energy and emit large amounts of CO2. Biomass-derived glycerol steam reforming is an attractive alternative to traditional reforming to reduce the dependence on hydrocarbon resources and mitigate climate change. This research aims to analyze a mass- and heat-integrated multi-tubular membrane reactor, containing nitrobenzene hydrogenation (exothermic-side) and glycerol steam reforming (endothermic-side) for co-production of aniline and syngas. In this process, hydrogenation... 

In this work, the electrophoretic deposition method was utilized to immobilize TiO2 particles on stainless steel substrates. In addition, for the first time, statistics-based experimental design using response surface methodology was employed to investigate the effect of four key coating parameters (i.e. applied voltage, calcination temperature, photocatalyst weight percentage, and deposition time) on the photocatalytic degradation. Analysis of variance revealed that the proposed model was adequate. X-ray diffraction and scanning electron microscope were used to evaluate the effects of the parameters on degradation efficiency. The optimum applied voltage, calcination temperature, catalyst... 

Synthesis of poly(2,5-dimethoxyanilie) (PDMA) catalyzed by nano reengineered horseradish peroxidase (HRP) with dendritic macromolecules, was studied as a function of reaction media. UV-vis, gel permeation chromatography and conductivity measurements were used to explain how the reaction media compositions influence the physical properties of PDMA. Nanostructured PDMA was also synthesized by oxidative polymerization in a novel and green bi-catalyst system involving HRP and ferric chloride. FTIR and UV-vis analysis confirmed the formation of emeraldine salt state of PDMA. The thermal stability of reengineered HRP granted further studies on the polymerization using bi-catalyst system at... 

We prepared three ferrite nanocatalysts: (i) copper ferrite (CuFe 2O4) (ii) ferrite where cobalt was substituted by nickel (Nix Co1-x Fe2O4, with x=0, 0.2, 0.4, 0.6), and (iii) ferrite where nickel was substituted by zinc (Zn y Ni1-y Fe2O4 with y=1, 0.7, 0.5, 0.3), by the sol-gel method. The X-ray diffraction patterns show that the ferrite samples have been crystallized in the cubic spinel structural phase. We obtained the size of grains by field emission scanning electron microscopy images and their magnetic properties by vibrating sample magnetometer. Next, carbon nanotubes were grown on these nanocatalysts by the catalytic chemical vapor deposition method. We show that the catalytic... 

Thiomorpholine 1,1-dioxides were prepared with double Michael addition reaction of aromatic amines to divinyl sulfone catalyzed by boric acid/glycerol in water. This catalyst system was also used for the Michael addition reaction of aromatic amines to electron-deficient alkenes. The reaction is simple and green and gives good to excellent yields  

Dye sensitizers loaded on TiO2 decrease the electron excitation energy, thereby improving the photocatalytic performance by causing an increase in sensitivity under visible light irradiation. Three dye sensitizer precursors, Mordant Orange 1, N3 (red dye) and Cobalt (II) Phthalocyanine Tetrasulfonate (CoPcTs), were utilized to load the photocatalyst. The rate of the electron trapping process on platinum is clearly compatible with the migration rate of boundary electrons. Consequently, the migration of boundary electrons from the conduction band towards electron acceptors is increased by loading platinum onto the titanium dioxide. In this research, TiO2 was synthesized from a titanium... 

Ni II-(N,N′-bis(2,4-dihydroxyacetophenone)-2, 2-dimethylpropandiimine (Ni II{salnptn(4-OH) 2}) complex has been encapsulated within the supercage of zeolite-NaY by reacting Ni 2+-exchanged NaY with the flexible Schiff-base ligand that diffuses into the cavities. The encapsulated complex is characterized by EDX, scanning electron microscopy, powder X-ray diffraction, FT-IR, and cyclic voltammetry studies. Density functional calculation is being carried out on both the free nickel Schiff-base complex and that encapsulated in NaY zeolite to investigate changes in structural parameters, energies of the HOMO and LUMO, and absolute hardness and softness. Electrochemical properties of the NaY... 

In this research, ultrahigh-molecular-weight polyethylene (UHMWPE)/multiwalled carbon nanotube (MWCNT) nanocomposites with different nanotube concentrations (0.5, 1.5, 2.5, and 3.5 wt %) were prepared via in situ polymerization with a novel, bisupported Ziegler-Natta catalytic system. Magnesium ethoxide [Mg(OEt) 2] and surface-functionalized MWCNTs were used as the support of the catalyst. Titanium tetrachloride (TiCl 4) accompanied by triethylaluminum constituted the Ziegler-Natta catalytic system. Preparation of the catalyst and the polymerization were carried out in the slurry phase under an argon atmosphere. Support of the catalyst on the MWCNTs was investigated with Fourier transform... 

In this experimental study, a kinetic model has been developed for Fischer-Tropsch synthesis reactions by using sol-gel technique and Fe/Ni/Al 2O 3 as the catalyst (40% Fe/60% Ni/40 wt.%Al 2O 3) in a differential fixed-bed micro reactor assuming no internal or external diffusion. Operating conditions of the reactor were as follows: total pressure 1-12 atm; Temperature 220-260 °C; H 2/CO feed ratio 1.5-2; gas hourly space velocity 2100-7000 cm 3(STP)/h/ g cat and conversions of 6-37% of hydrogen and 7-21% of carbon monoxide. Mass transfer limitations were investigated by changing synthesis gas velocity in reactors which differ in size. Based on the hypothesis that water inhibits the intrinsic... 

In this study, WO 3 nanocrystallites were first produced by laser ablation of W target in deionised water. To synthesize palladium, a PdCl 2 solution (0.2 g/L) was added to the liquid. Transmission electron microscope revealed successful synthesis of tungsten oxide nanocrystallites along with the production of Pd and core-shell Pd/WO3 nanoparticles. Gasochromic behavior was examined by hydrogen bubbling into Pd/WO 3 liquid in which a transition to blue absorbing state was observed. Optical absorption spectra of the colored liquid represented different sharp small polaron absorbing peaks below 3 eV and the peaks intensity was observed to be varied with Pd:WO 3 ratio. Time variations of... 

A polymeric manganese(II) complex with the general formula [Mn(O 2CCH2NH2CH2CO2) 2(H2O)2]n from reaction of iminodiacetatic acid and manganese(II) perchlorate under nitrogen in water, was synthesized and characterized. The structure of the complex was determined using single-crystal X-ray diffraction, elemental analysis, IR and UV-vis spectra. This complex exhibited excellent catalytic activity and selectivity for oxidation of various alcohols and sulfides to the corresponding aldehydes/ketone and sulfoxides using urea hydrogen peroxide and oxone (2KHSO 5·KHSO4·K2SO4), respectively, as oxidants under air at room temperature. The easy preparation, mild reaction conditions, high yields of the... 

In this study, α -Fe2O3 (hematite) nanoparticles were synthesised by a sonochemical method. The influence of different factors such as chemical composition of the precursors, atmosphere of the reactions and type of the sonicator on the chemical formula, crystallinity, morphology and size of the obtained products were investigated. Powder X-ray diffraction, scanning electron microscopy and IR spectroscopy, were used to characterise the nanostructures. The catalytic tests were performed in the reaction of methyl phenyl sulphide oxidation. The results exhibit the good catalytic performance of the as-prepared α -Fe2O3 nanoparticles  

There are increasing evidences that adjusting the chemistry of the injecting water improves the oil recovery efficiency. However, the underlying mechanisms for this technique which is referred to as "smart waterflood" have not yet been thoroughly understood. It is needed to explore the role of individual ions through set of different tests, to find the right mechanisms behind "smart waterflood". This study is focused on the fluid/solid (carbonate) interactions through systematic wettability measurement. Contact angle measurements accompanied by spontaneous imbibition tests were employed to determine the role of individual monovalent and divalent ions in wettability alteration process by... 

Copper and cobalt oxides supported on almond shell derived activated carbon (AC) with different loadings were synthesized by sequential and co-deposition-precipitation methods leading to Cu(shell)/Co(core)/AC, Co(shell)/Cu(core)/AC and Cu-Co(mixed)/AC catalysts that were subsequently used for catalytic oxidation of gaseous mixtures of toluene and cyclohexane in air in a tubular flow reactor. The catalysts and the support were characterized by Boehm test, Brunauer-Emmett-Teller (BET) surface area, X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy... 

In this work, the individual and interaction effects of three key operating parameters of the photocatalytic disinfection process were evaluated and optimized using response surface methodology (RSM) for the first time. The chosen operating parameters were: reaction temperature, initial pH of the reaction mixture and TiO2 P-25 photocatalyst loading. Escherichia coli concentration, after 90 minutes irradiation of UV-A light, was selected as the response. Twenty sets of photocatalytic disinfection experiments were conducted by adjusting operating parameters at five levels using the central composite design. Based on the experimental data, a semi-empirical expression was established and applied... 

A novel modified pyrolytic graphite electrode with nano-diamond/graphite was fabricated. The electrochemical response characteristics of the modified electrode toward the epinephrine (EN) and uric acid (UA) were studied by means of cyclic and linear sweep voltammetry. The structural morphology and thickness of the film was characterized by SEM technique. The prepared electrode showed an excellent catalytic activity in the electrochemical oxidation of EN and UA, leading to remarkable enhancements in the corresponding peak currents and lowering the peak potentials. The prepared modified electrode acts as a highly sensitive sensor for simultaneous determination of EN and UA in the presence of... 

Catalytic ozonation has recently been used as a new means of contaminant removal from water and wastewater. In this study, bone charcoal (BC), a new catalyst prepared under laboratory conditions, was used to catalyze the ozonation of humic substances (HS) in aqueous solutions. The catalytic effect of bone charcoal and the relevant parameters of this ozonation process (solution pH, temperature, scavenger effect, humic acids concentration and BC dosage) were investigated. In the catalytic ozonation experiments, the degradation kinetics was investigated. The reaction rate and the rate constant were determined. The results showed that using a BC catalyst in the ozonation of HS produced a 1.43-... 

A facile approach for the preparation of core-shell structured poly(acrylic acid) (PAA)-coated Fe3O4 cluster@SiO2 nanocomposite particles as the support materials for the lipase immobilization is reported. Low- or high-molecular-weight (1800 and 100 000, respectively) PAA molecules were covalently attached onto the surface of amine-functionalized magnetic silica nanoacomposite particles. The successful preparation of particles were verified by scanning transmission electron microscopy (STEM), X-ray diffraction (XRD), vibrating sample magnetometer (VSM), thermogravimetric analysis (TGA), zeta potential measurement, and Fourier-transform infrared (FTIR) techniques. Once lipase is covalently... 

Ternary mesoporous nanocomposites of RGO/Fe3O4-ZnO were prepared successfully via hydrothermal technique. Fe3O4-ZnO core/shell nanoparticles were decorated on the surface of reduced graphene oxide platelet to improve charge separation efficiency and magnetic properties. The phase, microstructure and specific surface area of the prepared samples were determined via X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy/selected area electron diffraction (TEM/SAED) and Brunauer–Emmett–Teller (BET) techniques. A vibrating sample magnetometer (VSM) was used for recording the magnetization hysteresis curves. The methylene blue (MB)... 

In this work, we synthesized carbon hollow spheres (CHSs) using the silica templating method, encapsulated 2-mercaptobenzimidazole (MBI) inhibitor in the CHSs and evaluated their corrosion inhibition performance upon exposure of mild steel to a saline solution containing the released inhibitor. The effects of silica template surface modification on the CHS structure was evaluated, while the structure and morphology of the synthesized CHS was analyzed using field emission scanning electron microscope (FE-SEM), transmission electron microscope (TEM), Raman spectroscopy and X-ray diffraction (XRD) spectroscopy. Furthermore, thermogravimetric analysis (TGA), energy-dispersive X-ray spectroscopy...