Preparation of a spindle δ-MnO2@Fe/Co-MOF-74 for effective adsorption of arsenic from water

Abstract Making adsorbent with high adsorption efficiency and wide application is the most economical and effective method to remove arsenic from water. A simple in-situ synthesis method was used to combine the highly oxidized δ-MnO2 with the modified Fe/Co-MOF-74 structure of the metal organic framework. The new composite materials obtained have high adsorption rates in the pH range of 2–10. The isotherm and kinetic parameters of arsenic removal on Fe/Co-MOF-74 were well-fitted by the Langmuir and pseudo-second-order models. At room temperature, the maximum adsorption capacity of As(III) is 300.5 mg/g. Most common substances in water, such as carbonate, sulfate and humic acid, have no effect on As(III) adsorption, and only the presence of phosphate can inhibit the adsorption process of arsenic. The main adsorption mechanism is electrostatic adsorption and complexation. In conclusion, δ-MnO2@Fe/Co-MOF-74 is a kind of adsorbent with excellent performance in the removal of As (III) in water, which has a wide application prospect and a value of further study.