Utilisation of cobalt doped Iron based MOF for enhanced removal and recovery of methylene blue dye from waste water

Abstract In the present study attempts have been made to improve the adsorption performance of Fe-Benzene dicarboxylic acid metal organic framework for the removal of methylene blue dye from waste waters through cobalt doping. The removal efficiency of Co doped Fe-BDC MOF improved from 8.56 to 23.92 mg/g. Batch and column methods have been used to evaluate removal efficiency of the Co doped Fe-BDC MOF for removal of methylene blue. Effect of various parameters such as pH, amount of adsorbent, dye concentration, temperature, and contact time on dye removal has been studied. It has been observed that extent of adsorption increases in acidic medium and dye removal decreases on increasing pH of dye solution. Langmuir adsorption isotherm has been found to best fit the adsorption process. Thermodynamic parameters, evaluated for the dye-adsorbent system, revealed that the adsorption process is endothermic in nature. Experimental data were modeled by using pseudo-first, pseudo-second and intraparticle diffusion models. Pseudo-second-order kinetics was found to describe the adsorption of methylene blue on MOF. Column operations were made to achieve bulk removal of the dye. Column adsorption capacity has been found to be greater than the batch adsorption capacity. The improved maximum adsorption capacity of the Co doped Fe BDC MOF in comparison to the previously developed Fe BDC MOF establishes the significance of the present investigation.