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RISS 인기검색어
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- 저자 : Bahram Rezai (검색결과 5 건)
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Effect of impeller speed on the Ni(II) ion flotation
Fatemeh Sadat Hoseinian,Bahram Rezai,Elaheh Kowsari,Mehdi Safaric 한국자원공학회 2019 Geosystem engineering Vol.22 No.3
In this study, the effect of impeller speed on Ni(II) removal and water removal was evaluated in ion flotation. The results show that the Ni(II) removal increases with increasing impeller speed from 600 to 800 rpm from less than 41% to 88%, respectively, and after that, it decreases to 79% with increasing impeller speed to 900 rpm in the first 4 min of flotation. The water removal was increased with increasing impeller speed. The Ni(II) removal and water removal were modelled and described as the function of variables such as flotation time and impeller speed using the gene expression programming (GEP). The kinetics study also showed that the removal rate of Ni(II) ions and water were increased with increasing impeller speed.
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Mohammad Bagher Fathi,Bahram Rezai,Eskandar Keshavarz Alamdari,Richard Diaz Alorro 한국자원공학회 2018 Geosystem engineering Vol.21 No.2
The present study deals with the competitive adsorption of rhenium (Re) and molybdenum (Mo) ions onto Dowex 21K from single component and binary systems. The equilibrium adsorption data were obtained at different initial concentrations (50–250 mg/l), 12 h contact time, 290 K temperature, and resin dosage of 0.05 g at pH around 0.5. The single system equilibrium adsorption data were fitted via non-linear regression techniques to Langmuir, Freundlich, Temkin, and Dubinin–Radushkevich (D–R) isotherm models. Both Freundlich and D–R isotherms for Re and Langmuir and D–R isotherms for Mo suitably described the adsorption equilibrium data. Equilibrium isotherms for the binary adsorption of Re and Mo ions onto Dowex 21K have been analyzed using Extended Langmuir, Modified Langmuir, Extended Freundlich and Langmuir–Freundlich models. The competitive Extended Freundlich model fitted the binary adsorption equilibrium data satisfactorily and adequately. Results of investigation on the mutual interference effects of Mo ions on Re adsorption capacity indicated that although Dowex 21K has generally higher affinity toward Re ions, the adsorption of perrhenate ions () is suppressed by a factor of about 49% in the presence of molybdenum ions. The adsorption of perrhenate ion is affected by competitive inhibition and shield preventing effects.
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Nazanin Deihimi,Mehdi Irannajad,Bahram Rezai 한국자원공학회 2018 Geosystem engineering Vol.21 No.5
In this study, the activated red mud was used as a new and appropriate adsorbent for the removal of ferrocyanide and ferricyanide from aqueous solution. Predicting the removal percentage and adsorption capacity of ferro-ferricyanide by activated red mud during the adsorption process is necessary which has been done by modeling and simulation. The artificial neural network (ANN) was used to develop new models for the predictions. A back propagation algorithm model was trained to develop a predictive model. The effective variables including pH, absorbent amount, absorbent type, ionic strength, stirring rate, time, adsorbate type, and adsorbate dosage were considered as inputs of the models. The correlation coefficient value (R 2) and root mean square error (RMSE) values of the testing data for the removal percentage and adsorption capacity using ANN models were 0.8560, 12.5667, 0.9329, and 10.8117, respectively. The results showed that the proposed ANN models can be used to predict the removal percentage and adsorption capacity of activated red mud for the removal of ferrocyanide and ferricyanide with reasonable error.
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Arash Sobouti,Fatemeh Sadat Hoseinian,Bahram Rezai,Sara Jalili 한국자원공학회 2019 Geosystem engineering Vol.22 No.6
Prediction of lead recovery during the leaching process is required to increase the process efficiency by proper modeling. In this study, a new artificial neural network predictive model based on the particle swarm optimization (ANN-PSO) was developed to predict the lead recovery by a hydrometallurgical method of lead concentrate leaching using fluoroboric acid. A multi-layer ANN-PSO model was trained for developing a predictive model based on the main effective parameters on the lead leaching process. The input parameters of the ANN-PSO model were leaching time, liquid/solid ratio, stirring speed, temperature and fluoroboric acid concentration, while the lead recovery during leaching was the output. The results indicate that the proposed ANN-PSO model can be effectively predicted the lead recovery during lead concentrate leaching using fluoroboric acid.
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Mohammad Bagher Fathi,Farshad Nezhadshahmohammadi,Bahram Rezai,Richard Diaz Alorro 한국자원공학회 2019 Geosystem engineering Vol.22 No.3
Alteration adsorption properties of Re(VII) on two resins with different functional groups and structure, weak base/macroporous and strong base/gel type, Purolite A170 (A170) and Dowex 21K (21K) respectively, were investigated experimentally and interpreted by isotherm, kinetic and thermodynamic modeling. Following the comparison of coefficient of determination values, the Freundlich and D-R isotherm models were found to be more suitable for description of investigated systems (R2 > 0.99). The Langmuir isotherm capacities (qm) were indicated that the perrhenate ions (ReO4−) adsorption is higher for weak base/macroporous type resin rather than the other at pH 3 in the presence of 50–250 mg L−1 Re (166.67 and 142.86 mg g−1, respectively). Also, the results from EDX studies corroborated this phenomenon. The adsorption reaction on both adsorbents was found to be chemically with mean free energy, E, as 12.18 and 13.62 kJ mol−1 for A170 and 21K, respectively. Kinetics of adsorption was studied by fitting the data into different mechanisms, among which the pseudo-second order mechanism was found successful for both used resins, but in case of 21K, the rate of perrhenate ions uptake was more rapid than A170. That is possibly attributed to the presence of strong base (quaternary amine) in functional groups. ΔG values obtained were all negative for both resins indicating a spontaneous adsorption process. The positive values of both ΔH (3.34 kJ mol−1) and ΔS (27.31 J mol−1 K−1) obtained suggest an endothermic reaction and in increase in randomness at the solid–liquid interface during the adsorption onto the A170 resin while for 21K, the negative changes in enthalpy and entropy provide an indication that the process is endothermic as well as it follows associative mechanism.
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