Sulfur removal of gas oil using ultrasound-assisted catalytic oxidative process and study of its optimum conditions

Ultrasound-assisted oxidative desulfurization process (UAOD) was applied to reduce sulfur compounds of gas oil containing various types of sulfur content. The environmental regulation requires a very deep desulfurization to eliminate the sulfur compounds. UAOD is a promising technology with lower operating cost and higher safety and environmental protection. For the first time the typical phase transfer agent (tetraoctyl-ammonium-bromide) was replaced with isobutanol because using isobutanol is much more economical than TOAB, imposing no contamination. The reaction was carried out at optimal point with various temperatures, in single-, two- and three step-procedures, investigating the effect of gradual increase of H₂O₂ and TOAB being used instead of isobutanol. Total sulfur concentration in oil phase was analyzed by ASTM-D3120 method. The highest removal of about 90% for gas oil containing 9,500 mg/kg of sulfur was achieved in three-steps during 17 minutes of process at 62±2 °C when 180.3 mmol of H₂O₂ was used and extraction carried out by methanol.     

NO reduction over nanostructure M-Cu/ZSM-5 (M: Cr,Mn, Co and Fe) bimetallic catalysts and optimization of catalyst preparation by RSM

The selective catalytic reduction (SCR) of NO with NH₃ in the presence of oxygen over a series of H-ZSM-5 supported transition metal oxides (Co, Mn, Cr, Cu and Fe) was investigated. Among them, Cu/ZSM-5 nanocatalyst was found to be the most promising catalyst based on activity. The modification of Cu/ZSM-5 by adding different transition metals (Co, Mn, Cr and Fe) to improve the efficiency of NO conversion was studied. The results indicated that the Fe–Cu/ZSM-5 bimetallic nanocatalyst was the highest active catalyst for NO conversion (67% at 250 °C and 93% at 300 °C). Response surface methodology (RSM) involving central composite design (CCD) was employed to evaluate and optimize Fe–Cu/ZSM-5 preparation parameters (Fe loading, calcinations temperature, and impregnation temperature) in SCR of NO at 250 °C. The optimum condition for maximum NO conversion was estimated at 4.2 wt.% Fe loading, calcinations temperature of 577 °C and impregnation temperature of 43.5 °C. Under these condition, experimental NO conversion efficiency was 78.8%, which was close with the predicted value (79.4%).     

Effect of Organophosphorous Compounds as Coke Inhibitors on Coking Rate in the Pyrolysis of Naphtha

Abstract

The reduction in the rate of coke formation during naphtha pyrolysis due to the injection of triphenyl phosphine (TPP), tri-o-tolyl phosphine (TTP), and triphenyl phosphine oxide (TPPO) has been investigated in a jet stirred reactor at atmospheric pressure in the temperature range of 800–900°C. Coke formation was significantly reduced in the presence of the additives. The data are consistent with the formation of a metal–phosphorous complex that passivates the metal activity for coke formation. Scanning electron microscope (SEM) and energy dispersive X-ray (EDX) techniques were used for morphological and elemental surface analyses respectively. It was found, that coke formed in presence of organophosphorous inhibitors are softer and have less metal concentrations.     

Photocatalytic removal of NOx over immobilized BiFeO<Subscript>3</Subscript> nanoparticles and effect of operational parameters

Perovskite type BiFeO₃ (BFO) was synthesized by sol-gel auto-combustion method. Synthesized BFO was immobilized on the micro slides glass plates by sol-gel dip-coating method. The sample was characterized by XRD, FESEM, UV-Vis DRS, and BET techniques. The XRD pattern confirmed the perovskite structure, and from the Debye-Scherrer equation the average crystalline size was calculated as 19 nm. The FE-SEM images of prepared BFO showed porous structure with low agglomeration. The band gap energy was calculated about 2.13 eV, and the specific surface area (SSA) of prepared BFO nanostructure was obtained 55.1m² g^?1. The photocatalytic activity of prepared pure and immobilized BFO was investigated in the removal of NOx under UV irradiation, in the batch photoreactor. The effects of operational parameters such as initial concentration of NOx, light intensity and amount of coated photocatalyst, under identical conditions, were investigated. The results showed that the highest conversion of NOx was obtained as 35.83% in the 5 ppm of NOx with 1.2 g immobilized BFO and under 15 W illumination lamp.     

Bones Morphogenic Protein‐4 and retinoic acid combined treatment comparative analysis for in vitro differentiation potential of murine mesenchymal stem cells derived from bone marrow and adipose tissue into germ cells

Nowadays, infertility is no longer considered as an unsolvable disorder due to progresses in germ cells derived from stem lineage with diverse origins. Technical and ethical challenges push researchers to investigate various tissue sources to approach more efficient gametes. The purpose of the current study is to investigate the efficacy of a combined medium, retinoic acid (RA) together with Bone Morphogenic Protein‐4 (BMP4), on differentiation of Bone Marrow Mesenchymal Stem Cells (BMMSCs) and adipose‐derived mesenchymal stem cells (ADMSCs) into germ cells. Murine MSCs were obtained from both Bone Marrow (BM) and Adipose Tissue (AT) samples and were analyzed for surface markers to get further verification of their nature. BMMSCs and ADMSCs were induced into osteogenic and adipogenic lineage cells respectively, to examine their multipotency. They were finally differentiated into germ cells using media enriched with BMP4 for 4 days followed by addition of RA for 7 days (11 days in total). Analyzing of differentiation potential of BMMSCs‐ and ADMSCs were performed via Immunofluorescence, Flowcytometry and Real time‐PCR techniques for germ cell‐specific markers (Mvh, Dazl, Stra8 and Scp3). Mesenchymal surface markers (CD90 and CD44) were expressed on both BMMSCs and ADMSCs, while endothelial and hematopoietic cell markers (CD31 and CD45) had no expression. Finally, all germ‐specific markers were expressed in both BM and AT. Although germ cells differentiated from ADMSCs showed faster growth and proliferation as well as easy collection, they significantly expressed germ‐specific markers lower than BMMSCs. This suggests stronger differentiation potential of murine BMMSCs than ADMSCs.     

Performance of nanostructure Fe-Ag-ZSM-5 catalysts for the catalytic oxidation of volatile organic compounds: Process optimization using response surface methodology

Gas phase catalytic oxidation of ethyl acetate was studied in low concentration over Fe-Ag-ZSM-5 catalysts under atmospheric pressure. The effect of important parameters such as Ag loading, Fe loading, calcinations temperature and reaction temperature was investigated and the process conditions were optimized using response surface methodology (RSM) based on central composite design (CCD). The optimum condition for Ag loading, Fe loading, calcination temperature and reaction temperature was 5.17 wt%, 2 wt%, 580 °C and 350 °C, respectively. A maximum of 96% of ethyl acetate was removed under the optimum experimental conditions. The proposed model equation using RSM has shown good agreement with the experimental data, with a correlation coefficient (R²) of 0.949.     

Peroxi-coagulation degradation of C.I. Basic Yellow 2 based on carbon-PTFE and carbon nanotube-PTFE electrodes as cathode

The electrochemical treatment of solutions containing C.I. Basic Yellow 2 (BY2) in aqueous solutions with carbon-PTFE (polytetrafluoroethylene) and carbon nanotube (CNT)-PTFE electrodes as cathode has been studied. The fabricated electrodes were characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The amount of electrogenerated H₂O₂ on the surface of these electrodes was investigated, too. The results showed that the amount of H₂O₂ obtained with the CNT-PTFE electrode was nearly three times higher than that of carbon-PTFE electrode. The decolorization efficiency of BY2 in peroxi-coagulation process reached 62% and 96% in the first 10 min by carbon-PTFE and CNT-PTFE electrodes at 100 mA, respectively. The effect of operational parameters such as applied current, initial pH and initial dye concentration was studied in an attempt to reach higher decolorization efficiency. The degradation and mineralization of BY2 using CNT-PTFE electrode were followed by total organic carbon (TOC) and GC–MS analysis. The results of TOC measurements indicated that peroxi-coagulation with carbon-PTFE allowed 81% mineralization after 6 h of electrolysis; whereas peroxi-coagulation with CNT-PTFE yields 92% mineralization under the same conditions. GC–MS analysis verified the identity of intermediates and a reaction pathway based on them was proposed.     

Optimization and statistical modeling of catalytic oxidation of 2-propanol over CuMnmCo2−mO4 nano spinels by unreplicated split design methodology

Optimization of 2-propanol oxidation over CuMn_mCo_2?mO₄ nanospinels was carried out by a split design method. 15-term model was proposed to fit the experimental data. The model revealed that both whole plot and subplot variables have significant effects on conversion of 2-propanol. The model predicted the interaction of subplot and whole plot variables as well as their importance. The maximum conversion of 2-propanol was observed over CuMn₂O₄ (x₁ = 0.33, x₂ = 0, x₃ = 0.67) at calcination and reaction temperatures of 800 °C (z₁ = 1) and 300 °C (z₂ = 1), respectively. The predicted response and the response obtained from experiment for optimum conditions were 93.36 and 96, respectively.