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Roshanak Halvaeifard,Shahram Sharifnia 한국화학공학회 2018 Korean Journal of Chemical Engineering Vol.35 No.3
The effect of surfactants on the performance of BiOCl-ZnO nanoparticles was investigated in the photocatalytic degradation of an organic pollutant. BiOCl-ZnO nanoparticles, modified with cetyl trimethyl ammonium bromide (CTAB) and polyethyleneglycol-20000 (PEG) as two kinds of surfactants, were used as photocatalysts. The photocatalysts were characterized by SEM, XRD, FTIR and DRS analyses. Characterization of the photocatalysts indicated the positive role of the surfactants in increasing the surface area of the photocatalysts. The experimental results demonstrated that PEG had more impressive effect than CTAB on the photocatalytic performance. The effects of important operational parameters, such as initial pollutant concentration, catalyst dosage and pH, on the degradation efficiency were studied. About 96.3% of the organic pollutant removal from synthetic wastewater was obtained at optimal conditions under visible irradiation. Equilibrium data were well fitted to the Langmuir isotherm equation.
A visible-light-active BiFeO3/ZnS nanocomposite for photocatalytic conversion of greenhouse gases
Nasim Bagvand,Shahram Sharifnia,Elham Karamian 한국화학공학회 2018 Korean Journal of Chemical Engineering Vol.35 No.8
Given the changes in environmental conditions in the world, photocatalytic conversion of greenhouse gases is of great interest today. Our aim was to increase the photocatalytic efficiency of BiFeO3/ZnS (p-n heterojunction photocatalyst) by varying the molar ratio of ZnS to perovskite structure of BiFeO3 using hydrothermal synthesis. The results of X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), FT-IR spectroscopy showed the small crystal size and suitable distribution of ZnS particles on the BiFeO3 structure. The results of UV-visible, and photoluminescence (PL) spectroscopy analyses showed the good behavior of p-n heterostructure in absorption of visible light and lowering electron-hole recombination. The best visible light photocatalytic efficiency of CO2 reduction, 24.8%, was obtained by an equimolar ratio of BiFeO3/ZnS.
Narges Keshavarz Jafarzadeh,Shahram Sharifnia,Seyed Nezam Hosseini,Farshad Rahimpour 한국화학공학회 2011 Korean Journal of Chemical Engineering Vol.28 No.2
Response surface methodology (RSM) using D-optimal design was applied to optimization of photocatalytic degradation of phenol by new composite nano-catalyst (TiO_2/Perlite). Effects of seven factors (initial pH, initial phenol concentration, reaction temperature, UV irradiation time, UV light intensity, catalyst calcination temperature,and dosage of TiO_2/perlite) on phenol conversion efficiency were studied and optimized by using the statistical software MODDE 8.02. On statistical analysis of the results from the experimental studies, the optimum process conditions were as follows: initial pH, 10.7; initial phenol concentration, 0.5 mM; reaction temperature, 27 ℃; UV irradiation time,6.5 h; UV light intensity, 250W; catalyst calcination temperature, 600 ℃; and TiO_2/perlite dosage, 6 g/L. Analysis of variance (ANOVA) showed a high coefficient of determination (R^2) of 91.8%.
Sayed Reza Shabanian,Masoud Rahimi,Amin Amiri,Shahram Sharifnia,Ammar Abdulaziz Alsairafi,정재학,김우경 한국화학공학회 2012 Korean Journal of Chemical Engineering Vol.29 No.11
A numerical model was developed and validated to simulate and improve the reforming efficiency of methane to syngas (CO+H2) in an autothermal reactor. This work was undertaken in a 0.8 cm diameter and 30 cm length quartz tubular reactor. The exhaust gas from combustion at the bottom of reactor was passed over a Ru/γ-Al2O3 catalyst bed. The Eddy Dissipation Concept (EDC) model for turbulence-chemistry interaction in combination with a modified standard k-ε model for turbulence and a reaction mechanism with 23 species and 39 elementary reactions were considered in the combustion model. The pre-exponential factors and activation energy values for the catalyst (Ru) were obtained by using the experimental results. The percentage of difference between the predicted and measured mole fractions of the major species in the exhaust gas from combustion and catalyst bed zones was less than 5.02% and 7.73%,respectively. In addition, the results showed that the reforming efficiency, based on hydrogen yield, was increased with increase in catalyst bed’s thermal conductivity. Moreover, an enhancement of 4.34% in the reforming efficiency was obtained with increase in the catalyst bed wall heat flux from 0.5 to 2.0 kW/m2.
Seyed Nezamedin Hosseini,Masoud Zendehzaban,Shahram Sharifnia 한국화학공학회 2013 Korean Journal of Chemical Engineering Vol.30 No.3
Photocatalytic degradation of ammonia on supported TiO2 nanoparticles was investigated. The TiO2 nanoparticles used as photocatalyst were coated on light expanded clay aggregate granules (LECA), which is a porous and light weight support. Photocatalytic reaction activity of prepared catalyst was determined by ammonia degradation from water synthetically polluted with ammonia. Experiment results showed significantly high photocatalytic activity for the immobilized catalysts. The ammonia was removed more than 85% within 300 min of the process with optimum calcinations temperature 550 oC and pH 11. Kinetics of the photocatalytic reaction followed a pseudo-first order model. XRF, XRD and SEM analyses revealed a rather uniform coating of TiO2 on the support. By using floated TiO2/LECA as a photocatalyst in aqueous solution of NH3, the ammonia was photodegraded into N2 and H2 gases, while NO2− and NO3− were formed at very low concentrations.