Conference on Environmental Science and Technology

To further improve the adsorption performance of our synthesized metal organic framework (MOF)-based composite beads, components with favorable functional groups are introduced. In this study, polyethyleneimine (PEI), a suitable polymer with plenty of amine functional groups in its structure, was incorporated to increase the number of active sites for methyl orange (MO) adsorption. The effects of operating parameters such as pH and initial MO concentration on the MO adsorption performance of our previously optimized beads composed of chitosan (CS), MIL-101 (Fe), and PEI were investigated. In addition, kinetic and isotherm modelling using adsorption equilibrium data were performed using non-linear regression. High MO removal of at least 93% was achieved across a wide range of pH, while kinetic data followed a pseudo-second order equation with a coefficient of determination (R-squared) of 0.981, suggesting that chemisorption limits the rate of the reaction. Furthermore, isotherm studies revealed that the adsorption equilibrium data were best described by the Sips isotherm model (R-squared = 0.993), suggesting MO adsorption on the heterogeneous surface of the beads. With a maximum adsorption capacity of 1253.44 mg/g, results showed superior performance of the beads in removing MO from water. Finally, regeneration studies proved that the beads have a high regenerative ability, being able to maintain MO removal of over 98% throughout five cycles of adsorption and desorption.