Sonochemically synthesized microporous metal-organic framework for rapid and efficient ultrasonic-assisted removal of mercury(II) ions in water

Nowadays, water pollution through heavy metal ions is a great concern in all human communities. In this project, metal-organic frameworks (MOFs), which named by Zn₂(oba)₂bpy, with H₂oba = 4,4-oxybisbenzoic acid and bpy = 4,4-bipyridine linkers, were successfully synthesized. Properties of this MOF were performed using different techniques, such as FT-IR, XRD and SEM analysis. These frameworks have special characteristics like rapid, efficient and selective removal of metal ions from contaminated water. The use of an ultrasonic device plays an important role in shortening the absorption time of mercury(II) ions by increasing the absorbent dispersion in the solution. The adsorption capacity was affected by variables such as pH solution, Hg²⁺ initial concentration, adsorbent dosage and contact time. For Hg(II) metal ions the sorption capacities of 345 mg g^-1 and 315 mg g^-1 were obtained effectively by Zn₂(oba)₂bpy structures. The experimental adsorption data for Zn₂(oba)₂bpy MOF, is well suited with the pseudo-second-order kinetic model (R² = 0.9912), and the adsorption isotherms of Hg²⁺ metal ions are in good agreement with the Langmuir model. This work displays to remove Hg²⁺ ions from pollutant water under 30 min effectively.