• Environmental Engineering Research
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• v.25 no.4
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• pp.488-497
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• 2020

The present study investigates the feasibility of nitrogenous heterocyclic compounds (NHCs) (Pyridine-Quinoline) degradation by catalytic wet peroxidation (CWPO) in the presence of nanoscale zerovalent iron supported on granular activated carbon (nFe⁰/GAC) using statistical optimization technique. Response surface methodology (RSM) in combination with Box-Behnken design (BBD) was used to optimize the process parameters of CWPO process such as initial pH, catalyst dose, hydrogen peroxide dose, initial concentration of pyridine (Py) and quinolone (Qn) were chosen as the main variables, and total organic carbon (TOC) removal and total Fe leaching were selected as the investigated response. The optimization of process parameters by desirability function showed the ~85% of TOC removal with process condition of initial solution pH 3.5, catalyst dose of 0.55 g/L, hydrogen peroxide concentration of 0.34 mmol, initial concentration of Py 200 mg/L and initial concentration of Qn 200 mg/L. Further, for TOC removal the analysis of variance results of the RSM revealed that all parameter i.e. initial pH, catalyst dose, hydrogen peroxide dose, initial concentration of Py and initial concentration of Qn were highly significant according to the p values (p < 0.05). The quadratic model was found to be the best fit for experimental data. The present study revealed that BBD was reliable and effective for the determination of the optimum conditions for CWPO of NHCs (Py-Qn).

• Applied Chemistry for Engineering
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• v.23 no.6
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• pp.588-593
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• 2012

In this study, selective catalytic reduction (SCR) reaction was performed using liqufied petroleum gas (LPG) as a reductant for removing NOx. The catalysts were manufactured with different amounts of Cu and Fe supported on HZSM-5 in order to remove NOx. The NOx conversion ratio was studied with changing the temperature and the catalyst amount. The catalysts were manufactured by calcination with flowing the ambient air at $500^{\circ}C$ for three hours. Cupper of 1~4 wt% and iron of 0.5~2 wt% were supported on HZSM-5 of which Si/Al ratio were 80. According to the reaction results, the catalyst which Cu of 3 wt% supported on HZSM-5 showed the highest conversion rate. XRD, XPS, and TPR analysis were also performed for the characterization of catalysts.

• Korean Journal of Metals and Materials
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• v.49 no.12
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• pp.956-966
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• 2011

Bioleaching studies of metals from a spent catalyst were conducted using both adapted and unadapted bacterial cultures. The bacterium used in this experiment was Acidithiobacillus ferrooxidans. A comparison of the kinetics of leaching was made between the two cultures by varying the leaching parameters, including the pulp density, particle size and temperature. Both cultures showed similar effects with respect to the above parameters, but the leaching rates of all metals were higher with the adapted compared to the unadapted bacterial cultures. The leaching reactions were continued for 240 h in the case of the unadapted bacterial culture, but only for 40 h in the case of the adapted bacterial culture. The leaching reactions followed first order kinetics. In addition, the kinetics of leaching was concluded to be a diffusion control model; therefore, the product layers were impervious.

• International Journal of Internet, Broadcasting and Communication
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• v.7 no.2
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• pp.96-104
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• 2015

Fischer Tropsch reaction is one of the interesting topic for renewable and clean energy. Polymerization of carbon monoxide or carbon dioxide with hydrogen over metal supported catalyst can produce long chain hydrocarbons. Synthetic liquid hydrocarbons are promising alternative to fossil fuels. This research work has been focused on the synthesis of Fe based catalyst for Fischer Tropsch reaction. Mesoporous silica (MS) support prepared by a precipitation method using two different washing solution, distilled water (DW) and acid in ethanol solution (ET), and different calcination temperature. Then, Fe/MS was prepared by an incipient wetness impregnation method. All of samples were systematically characterized using various physical and chemical techniques. TEM and XRD analysis were used to ensure that the cubic Ia3d mesostructure is stable after calcination. FTIR spectra are useful to ascertain the existence of template in the support. TPR studies were also used to understand the nature of Fe species and their reducibility. The results reveal that washing the support with distilled water and calcination at $550^{\circ}C$ can efficiently remove the triblock copolymer templates. The existence of template in the support affects the textural properties of all catalyst investigated.

• Resources Recycling
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• v.3 no.1
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• pp.17-24
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• 1994

Recovery of precious metal values from petrochemical spent catalyst is important from the viewpoint of environmental protection and resource recycling. Two types of spent catalysts were used in this study. One used in the manufacture of ethylene contains 0.3% Pd in the alumina substrate. The other used in oil refining contains 0.3% Pt and 0.3% Re. Both spent catalysts are roasted to remove volatile matters as carbon and sulfur. Then, metallic Pd powder from Pd spent catalyst is obtained in the course of grinding, hydrochloric acid or aqua regia leaching and cementation with iron. For the recovery of Pt and Re from Pt-Re spent catalyst, Pt and Re are leached with either HCI or aqua regia, first. Metallic Pt powder is recovered from the leach solution by cementation with Fe powder. Re in sulfide form is precipitated by the addition of sodium sulfide to the solution obtained after Pt recovery. It is found that 6N HCI can be successfully used as leaching agent for both types of spent catalyst. 6N HCI is considered to be better than aqua regia in consideration of reagent and equipment cost.

• Clean Technology
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• v.30 no.1
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• pp.62-67
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• 2024

In this study, an alkali metal Na was introduced into iron-based catalysts used in the carbon dioxide-based Fischer-Tropsch process by wet impregnation and physical mixing methods to compare their performance. The as-prepared catalysts were evaluated for reactivity at 3.5 MPa, 330 ℃, feed ratio of H₂/CO₂ = 3 with a space velocity of 4,000 mL h^-1 g_cat^-1. Comparing the two catalysts, it was found that Na was uniformly distributed throughout the catalyst when wet-impregnated, but Na for physically mixed catalyst was relatively located on the surface of the catalyst. In addition, the wet-impregnated catalyst showed higher liquid hydrocarbon (C₅₊) yield and lower CO selectivity. In conclusion, the effect of Na distribution in the catalyst on the reaction was identified and can be controlled by the introduction method.

• Korean Chemical Engineering Research
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• v.50 no.2
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• pp.358-364
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• 2012

The kinetics of the Fischer-Tropsch synthesis and water gas shift reactions over a precipitated iron catalyst were studied in a 5 channel fixed-bed reactor. Experimental conditions were changed as follows: synthesis gas $H_2$/CO feed ratios of 0.5~2, reactants flow rate of 60~80 ml/min, and reaction temperature of $255{\sim}275^{\circ}C$ at a constant pressure of 1.5 MPa. The reaction rate of Fischer-Tropsch synthesis was calculated from Eley-Rideal mechanism in which the rate-determining step was the formation of the monomer species (methylene) by hydrogenation of associatively adsorbed CO. Whereas water gas shift reaction rate was determined by the formation of a formate intermediate species as the rate-determining step. As a result, the reaction rates of Fischer-Tropsch synthesis for the hydrocarbon formation and water gas shift for the $CO_2$ production were in good agreement with the experimental values, respectively. Therefore, the reaction rates ($r_{FT}$, $r_{WGS}$, $-r_{CO}$) derived from the reaction mechanisms showed good agreement both with experimental values and with some kinetic models from literature.

• Journal of the Korean Chemical Society
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• v.58 no.2
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• pp.205-209
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• 2014

Hematite iron oxide (${\alpha}$-$Fe_2O_3$) nanowalls were fabricated on aluminum substrate by a facile solvent-assisted hydrothermal oxidation process. The XRD and EDS patterns indicate that the sample has a rhombohedral phase of hematite $Fe_2O_3$. FE-SEM, TEM, HR-TEM, SA-ED were employed to characterize the resulting materials. $N_2$ adsorption-desorption isotherms was used to study a BET surface area. Their capability of catalytic degradation of titan yellow GR azo dye with air oxygen in aqueous solution over $Fe_2O_3$ catalysts was studied. The result indicates that the as-prepared product has a high catalytic activity, because it has a larger surface area. Langmuir and Freundlich isotherms of adsorption dye on the catalysts surface were investigated and the decomposition of titan yellow GR follows pseudo-first order kinetic.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1114-1115
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• 2008

In this paper, we study the optical characteristics of low iron glass for photovoltaic modules fabrication. Tow types of glasses are examined by optical transmittance and reflection measurement. Also, by making laminated glass, we analyze the difference between glass maker. Mini-PV module is fabricated to compare optical reflectance through lamination process. Anti-reflection and catalyst-coated glasses are suggested for advanced technology to obtain high electrical generation output. The specific analysis is shown in the following paper.

• Journal of Powder Materials
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• v.17 no.6
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• pp.489-493
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• 2010

Nickel-based and iron-based alloys have been developed and commercialized for a wide range of high performance applications at severely corrosive and high temperature environment. This alloy foam has an outstanding performance which is predestinated for diesel particulate filters, heat exchangers, and catalyst support, noise absorbers, battery, fuel cell, and flame distributers in burners in chemical and automotive industry. Production of alloy foam starts from high-tech coating technology and heat treatment of transient liquid-phase sintering in the high temperature. These technology allow for preparation of a wide variety of foam compositions such as Ni, Cr, Al, Fe on various pore size of pure nickel foam or iron foam in order for tailoring material properties to a specific application.