Preparation, Characterization and Removal of Acid Blue 129 and Erioglaucine Dyes from Aqueous Solution by Corn Cob...

Herein, corn cobs (maize) have been converted into an activated carbon by subjecting to carbonization which were then treated with 1:1 solution of HCl and HNO₃ and finally passed through C₆H₁₂ solution and finally activated at a high temperature of 400◦C. The obtained activated sample was subjected to XRD, EDX, and SEM analysis. The surface area was estimated as 913 m²/g using a reported method in literature. The synthesized activated carbon was utilized as sorbent for acid blue 129 and Erioglaucine dyes. The kinetics of the process was evaluated at 20, 40, and 60 °C with best fitting achieved with pseudo-2nd order kinetics model. The correlation coefficient (R²) of the Langmuir model was high approaching to 1 thus exhibited best fitting of the data. The maximal adsorption capacity was 769.23 mg/g for erioglaucine and 833.33 mg/g for acid blue 129 recorded at 333 K. The thermodynamic parameters such as Gibbs free energy, enthalpy and entropy changes were also determined. The ΔG° and ΔH° (- 16.805 kJmol^- 1 & - 9.054 kJmol^- 1) values were negative indicated the feasibility of the process and its exothermic nature. The increase in disorder at solid-solution interface during the adsorption process was evident from the positive values of ΔS° (79.253 JK^- 1 mol^- 1 & 39.633 JK^- 1) indicated the spontaneity of the process. Further equilibrium was established from 5 to 7 min for both the dyes whereas optimum adsorbent dosage selected was 0.01 g. The synthesized activated carbon has been prepared from a renewable biomass source therefore; it could be the best alternative of synthetic water reclamation methods subjected to further validation by other researchers.