Iranian Journal of Chemical Engineering (IJChE)

Abstract In this work, zeolite 13X with porosity structure has been used as an adsorbent for adsorption of CO2 flue gas. The effect of operating conditions including pressure and time on adsorption capacity were investigated. The experiments conditions are constant temperature, the range of pressure 1 - 9 bar and the registration of adsorption capacity with passing of time. Experimental data were adjusted with adsorption isotherm models including two and three parameters isotherm. Also the process was studied in terms of kinetic models and after the implementation of the experimental data with kinetic models, the speed of this process equations were obtained. The best kinetic model for this process was selected first order equation. The results showed that adsorption capacity of 13X is 71.5 mg/g at pressure of 8 bars. Also the result indicate that 13x has high capacity at low pressures. With regard to achieved results for adsorption isotherm modeling, the adsorption isotherm followed of the three-parameter and among three-parameter models, Toth isotherm can be interpreted the process. Also the results of the fixed bed indicate a very high adsorbent selectivity to carbon dioxide adsorption and there was little oxygen and nitrogen adsorption.

Abstract In this paper, catalytic oxidation of CO over the LaFe1-xCuxO3 (x= 0, 0.2, 0.4, 0.6) perovskite-type oxides was investigated. The catalysts were synthesized by sol-gel method and characterized by XRD, BET, FT-IR, H2-TPR and SEM methods. The catalytic activity of catalysts was tested in catalytic oxidation of CO. XRD patterns confirmed the synthesized perovskites to be single-phase perovskite-type oxides. The synthesized perovskite catalysts show high activity in the range of reaction temperature (50 - 300 ºC). The substitution of Cu in B-site of the perovskite catalysts enhanced their catalytic activity for CO oxidation. Among different synthesized perovskite catalysts, LaFe0.6Cu0.4O3 has the highest activity: nearly complete elimination of CO was achieved at 275 ºC with this catalyst. Kinetic studies for CO oxidation were performed based on power law and Mars-van Krevelen mechanisms. According to kinetic calculations, the most probable mechanism is the MKV-D (dissociative adsorption of oxygen) which can predict the experimental data with correlation coefficient of R2 > 0.995.

Abstract This article reports the application of the homogenous UV/ persulfate process, activated with iron copper ions, for the treatment of quinoline (Qu) in aqueous solutions. A photo-reactor with a radial falling solution film around the UV lamp was utilized. Under established optimum conditions of [Qu]0= 40 mg/L, [PS]= 1000 mg/L, pH 6, [Fe2+] / [Cu2+]= 1 mg/L and after 70 min, 88.3%, 94.8% and 96.4% degradations were achieved with UV/PS, UV/PS/Fe2+ and UV/PS/Cu2+ processes, respectively. Accordingly, total organic carbon (TOC) removals were 31.2%, 36.1% and 82.2% after 120 min, which highlights the amazing power of copper ions in the treatment. For each case, pseudo first order reactions were obtained for the used processes. The required irradiation energy per cubic meter of aqueous solutions was 127.6, 100.5 and 71.8 kWh for the used processes, respectively. Meanwhile, the role of active radicals was investigated using radical scavengers of ethanol and tert-butyl alcohol, indicating about 48.9% contribution of sulfate radicals in the degradation mechanism.

Abstract Adsorption capacity of Cr(VI) onto activated carbon, almond and apricot shells was investigated in a batch system by considering the effects of various parameters like contact time, initial concentration, pH , temperature, agitation speed, absorbent dose and particle size. The adsorption was solution pH dependent and the maximum adsorption was observed
at solution pH of 2.0. The amounts of Cr(VI) adsorbed increased with increase in dose of both adsorbents and their contact time. A contact time of 30 min was found to be optimum. Experimental results show low cost biosorbent was effective for the removal of pollutants from aqueous solution. The pseudo-second-order kinetic model gave a better fit of the experimental data compared to the pseudo-first-order kinetic model. Experimental data showed a good fit with the Freundlich isotherm model.