Iranian Journal of Catalysis
Volume:9 Issue: 3, Summer 2019

Ovalbumin, as the major component of egg-white, is a globular, biocompatible, nontoxic and biodegradable phosphoglyco protein. This protein with the molecular weight of 44.5 kDa, contains 385 residues of amino acids with isoelectric point (pI) of 4.5. Many purification procedures have been reported for egg-white proteins such as gel permeation and anion exchange chromatography. In this study, we have reported a new inexpensive protocol using acetic acid and sodium chloride for extraction and purification of egg white nano-ovalbumin. The effective performance of this protein as a biocatalyst was proved through synthesis of N-substituted pyrrole derivatives. This reported innovative biomethodology has some advantages such as less pollution, mild reaction conditions, reusability of biocatalyst and excellent yields.

Bamboo is one of the important biopolymers which is used in chemistry. In this work, for the first time, a solid acid catalyst from bamboo was prepared from the reaction of sawdust bamboo and chlorosulfonic acid. Relevant properties of catalyst were investigated by FT-IR, XRD, SEM and TGA. The sulfonated bamboo (bamboo-SO3H) with several acid functional groups was utilized as highly efficient, heterogeneous and reusable catalyst for synthesis of bis(indolyl)methanes in short reaction times with excellent yields. Also, the novel solid acid catalyst was reused without any appreciable loss in activity.

In this research, a new effective photocatalyst was prepared by supporting ZnO on a Todorokite (TD). This catalyst was characterized by employing scanning electron microscopy (SEM-EDX) and X-Ray Diffraction (XRD) patterns. The optical properties of the samples were measured by diffuse reflectance spectroscopy (DRS). The purpose of using the ZnO/TD as a photocatalyst was to reduction Cr(VI), which is a pollutant in water. Experiments were carried out under different operating conditions including an initial concentration of Cr(VI), photocatalyst amounts and pH values. To optimize processes and obtain a mathematical model, the researcher used a full factorial design (with three factors at three levels). The optimal conditions were determined where the amount of photocatalyst= 200 mg L-1, pH= 2 and concentration of Cr(VI)= 15 ppm. The reduction efficiency in an optimal condition was 97.73%. The experimental results showed that kinetic was the first order and k= 0.1489 min–1.

Two different possible mechanisms of water gas shift reaction including formate and redox mechanisms on the Ag5 cluster were investigated using DFT computations. All the elementary steps involved in both mechanisms were considered. It was observed that dissociation of H2Oads and OHads, as well as formation of CO2(ads), required activation energy. For these steps, transition state structures were determined and their corresponding activation energies were calculated. For both mechanisms, the highest activation energy (402.34 kJ mol-1) was related to the dissociation of OHads as the rate limiting step. The calculated activation energy of CO2(ads) formation according to the redox mechanism (COads + O ads → CO2(ads)) was 9.32 kJ mol-1 indicating that this step was relatively fast on the surface of Ag5 cluster. It was observed that, CO2(ads) formation according to the formate mechanism occurred through three consecutive steps where the dissociation of formate (HCOO(ads) → CO2(ads) + Hads) had the highest activation energy, 171.53 kJ mol-1.

In this work, a Co-Fe-Ni catalyst was prepared and the effect of a range of operational variables such as gas hourly space velocity (GHSV), calcination temperature, calcination time and agent on its catalytic performance for green-fuels production was investigated. By application of different characterization techniques such as XRD, BET, TGA/DSC, and SEM, it was found that these parameters have great effects on the structure, porosity, morphology and physic-chemical properties of this catalyst. The optimum conditions were found for the samples which were calcined at 550 ℃ in air for 6 hours, and operated at 300 ℃ and 4800h-1 as the reaction temperature and GHSV respectively. Results also revealed that any increase in the calcination temperature promotes the product shifting towards heavier hydrocarbons (more C5+ production). Calcination in air atmosphere was more effective than calcination in N2 atmosphere.

In this study, Nitrogen doped TiO2 photocatalysts were prepared by the sol gel method and physicochemical properties were characterized by X-ray diffraction (XRD), and scanning electron microscopy (SEM), photoluminescence, and energy dispersive X-ray spectroscopy (DRS) techniques. The XRD data indicated that the nanoparticles had the same crystals structures as the pure TiO2. Photocatalytic properties of the nitrogen doped TiO2 nanocatalyst and pure TiO2 were compared for degradation of Blue 5 dye in visible light irradiation and the DRS results showed that the band gap of doped photocatalyst was smaller than that of the undoped TiO2 and there was a shift in the absorption band toward the visible light region. The Photocatalytic properties of the nitrogen doped TiO2 nanocatalyst wereemployed for degradation of crystal Blue 5 dye under visible light irradiation. The effects of pH, amount of photocatalysts,catalyst dosage, and dye concentration were also examined. The best results were reported for the concentration of 20 mg/L N-TiO2 nano-particles. Also results showed that the photodecomposition of N-TiO2 is complete at pH 11. Total organic carbon (TOC) analysis indicated 30 % mineralization of Blue 5 after 75 min irradiation.

Ni catalysts supported on Nano porous catalysts were prepared by the impregnation method and tested for vapor phase hydrogenation of benzene. The textural and physico-chemical properties of Ni catalysts were characterized by the X-ray diffraction, Fourier-transform infrared spectroscopy, scanning electron microscope and N2 adsorption-desorption analysis. The catalytic evaluation revealed that the best selectivity to benzene (> 84%) and high stability with the low coke deposition (< 1.1%) are related to Ni/Folded Sheets Mesoporous Materials-No. 16. The kinetics of benzene hydrogenation has been examined as a function of benzene and hydrogen pressures at various temperatures. Two kinetic models based on power law and Langmuir-Hinshelwood mechanisms were developed for the reaction and compared with the obtained experimental data. The apparent kinetic parameters were estimated using the multiple regression analysis. Both these models present the good results.

This research describes application of a mesoporous nanostructured material based on basic ionic liquid anchored to silica, i.e. nano-2-(dimethylamino)-N-(silica-n-propyl)-N,N-dimethylethanaminium chloride {nano-[DMSPDE][Cl]}, as a highly effective and heterogeneous nanocatalyst for the production of 2-amino-4H-chromenes. The one-pot multi-component reaction of aromatic aldehydes with malononitrile and 1-naphthol in the presence of nano-[DMSPDE][Cl] under solvent-free conditions affords the title compounds with high yields in short times.

ZnO and 2% Fe doped ZnO photocatalytic nanomaterials were successfully synthesized by successive ionic layer adsorption and the reaction (SILAR) method. The characterizations of these nanomaterials were carried out using XRD, SEM and EDX techniques. XRD study shows that the samples have a hexagonal wurtzite crystal structure, size of which is in the range 21-23 nm. SEM shows nanoflakes or nano flower-like morphology, while EDX reveals the compositional analysis. In this paper, we investigated photocatalytic degradation of an aqueous suspension of methyl orange (MO) dye as a model pollutant. Degradation of dye was monitored by the spectrophotometric method. The effects of various parameters such as pH, contact time, initial dye concentration and catalyst dose were studied. in optimized process, the maximum degradation obtained using ZnO was 88 % and that using Fe doped ZnO was 94 % at a pH value of 8. We have concluded that, compared to ZnO, the 2% Fe doped ZnO is a promising photocatalyst for degradation of MO.

Mahmoud Zarei was born in Hamedan, Iran in 1986. He received his B.Sc. in pure chemistry (2010) from Islamic Azad University Arak and M.Sc. in organic chemistry (2013) at Bu-Ali Sina University, Iran. Also, he received his Ph.D. in organic chemistry (2017) under the supervision of Prof. Mohammad Ali Zolfigol. He is currently working towards his postdoctoral under the supervision of Prof. Mohammad Ali Zolfigol. His research interest is the synthesis, characterization and applications of homogeneous and heterogeneous reagent and catalyst in organic synthesis.