Fast and Efficient Removal of Anionic Dyes from Water by Hierarchical Porous MIL-101(Cr)

Organic dyes pollution has caused significant threat to flora, fauna and humans because the toxic of dyes. In this work, with the help of acetic acid as a defect initiator, the hierarchical porous MIL-101(HP-MIL-101) has been synthesized and used for removing anionic dyes Eosin y (EY), Methyl orange (MO), Congo red (CR) and Acid fuchsin (AF) from water. Due to its positive surface charge, larger specific surface area, well-matched pore structure, and the charge, size, and diameter of dyes, HP-MIL-101 showed rapid adsorption and an excellent maximum adsorption capacity of 425 and 336 mg⋅g^− 1 for CR and AF, respectively. A series of batch experiments were carried out to investigate the impact of various key factors, including adsorption duration, initial dye concentration, and temperature. In addition, the kinetics, isotherm, and thermodynamics about the adsorption properties were also discussed. In addition, HP-MIL-101 showed stable and high reusability for at least three cycles, with an efficiency of over 95% without significant structural changes. This study highlights the potential of hierarchical porous MOF for mitigating dye pollution and advancing sustainable water treatment methodologies.