Pectin microgel particles as high adsorption rate material for methylene blue: Performance, equilibrium, kinetic, mechanism and regeneration studies

The pectin gel has been proved to be an effective material for methylene blue (MB) removal, but it presented low adsorption rate. To get over the vice, the pectin microgel particles (PMP) was prepared. No matter high or low initial MB concentration, the PMP presented high adsorption rate with equilibrium time of 20 min. The adsorption process based on monolayer adsorption and adsorbance of 284.09 mg/g was obtained. What's more, the adsorption process was electrostatic adsorption with mean free energy of 74223 kJ/mol. The pseudo-second-order kinetic model fitted perfectly to the experimental data. The MB uptake was controlled by film diffusion mechanism. Furthermore, the recovery efficiency of regenerated PMP were higher than 80% after three cycles. The present study showed the PMP presented acceptable adsorbance, high adsorption rate and recovery efficiency. Thus, we believe that the PMP was a promising candidate for MB cleanup. (C) 2018 Elsevier B.V. All rights reserved.