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Recovery of Vanadium Oxide from Bayer Process Liquor of Jajarm Alumina by Zeolite Nanocomposite

Bagheri, Reza | 2025

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  1. Type of Document: Ph.D. Dissertation
  2. Language: Farsi
  3. Document No: 58271 (07)
  4. University: Sharif University of Technology
  5. Department: Materials Science and Engineering
  6. Advisor(s): Yoozbashizadeh, Hossein; Halali, Mohammad; Salehi Rad, Alireza
  7. Abstract:
  8. In this study, the recovery of vanadium from the liquor solution of Iran Alumina Company was investigated using two-component and three-component nanocomposites including Zeolite A, Zeolite X, Magnetite and Amberlite IRA400. During this study, the synthesis of nanocomposites was analyzed using XRD, FTIR, FESEM and HRTEM methods. The effect of the percentage of zeolite A, zeolite X and Amberlite IRA400 as the second component in the magnetite-containing nanocomposite was evaluated. The findings showed that the best weight percentage for zeolite A, zeolite X and Amberlite IRA400 were 15, 5 and 50%, respectively. Then, the optimal composition for the three-component nanocomposite was selected as magnetite - 20% zeolite A -30% amberlite. Next, the effects of pH, adsorbent content, temperature and time on the recovery of vanadium from liquor solution were studied using two-component nanocomposites of Magnetite - 20% Zeolite A (M-Z), Magnetite - 50% Amberlite IRA400 (M-R) and three-component nanocomposites (M-Z-R). The results indicated that the recovery of vanadium by the M-Z-R nanocomposite increased 20 and 18%, respectively, compared to Zeolite A and Magnetite alone, indicating a synergistic effect due to the formation of the composite. Among the synthesized nanocomposites, the M-Z-R nanocomposite showed the best performance with 86% recovery of vanadium at pH 8, adsorbent content of 50 g.L-1, temperature of 45°C and time of 110 minutes. To investigate the isotherm of the adsorption process, Langmuir, Freundlich and Dubinin-Radushkevich (D-R) models were analyzed. The results showed that the M-R nanocomposite had the best fit with the Langmuir model, which indicated the adsorption of a monolayer of vanadium by this adsorbent. The M-Z and M-Z-R nanocomposites also exhibited an acceptable correlation coefficient with all three models; this is due to the heterogeneity of the adsorbent surface due to the presence of zeolite with different cations such as magnesium and calcium. The adsorption capacity calculated from the Langmuir model for the M-Z, M-R and M-Z-R nanocomposites was determined to be 6.95, 10.08 and 13.05 mg.L-1, respectively, which was very close to the values obtained from the D-R model. Also, the adsorption energy for these three adsorbents was calculated to be 20.24, 12.31 and 18.02 kJ.mol-1, respectively, indicating the formation of a strong chemical bond between the adsorbent and vanadium. In addition, the study of the recovery of vanadium from the synthetic solution free of other impurities showed that the presence of competing ions in the liquor solution caused only a 7% decrease in the adsorption capacity of the nanocomposite. First-order, second-order, interparticle and Elovich kinetic models were evaluated to analyze the kinetic behavior of the nanocomposites. According to the correlation coefficient, the second-order kinetic model had the highest agreement with all three adsorbents; this indicates that the chemical reaction step between the vanadium anion and the nanocomposite controls the process. Based on this model, the rate constants for M-Z, M-R, and M-Z-R nanocomposites were obtained as 0.006, 0.007, and 0.006 g.min-1mg-1, respectively, indicating a relatively low rate of the process. The free energy and its function with respect to temperature for M-Z, M-R, and M-Z-R nanocomposites were obtained as -860.2, -2535.3, and -1583.3 J/mol, respectively, and 15606.2-5.53T, 23004.0-3.80T, and 21489.2-9.74T. These results indicate that the adsorption of vanadium by all three adsorbents is a spontaneous, endothermic, and entropy-increasing process. The activation energy of the reaction was also calculated to be 48.82 kJ.mol-1, which is within the range of chemisorption
  9. Keywords:
  10. Bayer Process ; Vanadium ; Ion Exchange ; Zeolite ; Nanocomposite ; Adsorption Process ; Metal Oxide Nanoparticles ; Mixed Liquor ; Bayer Liquor

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