Rapid and efficient ultrasonic-assisted removal of lead(II) in water using two copper- and zinc-based metal-organic frameworks

Today, water pollution through heavy metal ions is a major concern in all human communities. In this study, two metal-organic frameworks (MOFs), which named by Cu-BTC and Zn-BTC, with benzene-1,3,5-tricarboxylic acid linker, were successfully synthesized. Characterization of these two MOFs was performed using various techniques, such as FT-IR, XRD and SEM analysis. These frameworks have special properties 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 lead(II) ions by increasing the absorbent dispersion in the solution. The adsorption capacity was affected by variables such as pH solution, Pb2+ initial concentration, adsorbent dosage and contact time. For Pb(II) metal ions the sorption capacities of 333 mg g(-1) and 312 mg g(-1) were obtained effectively by Cu-BTC and Zn-BTC structures, respectively. The experimental adsorption data for Cu-BTC and Zn-BTC MOFs, are well suited with the pseudo-second-order kinetic model (R-2 = 0.99), and the adsorption isotherms of Pb2+ metal ions are in good agreement with the Langmuir model. This work exhibits two BTC-based MOFs to remove Pb2+ from pollutant water in < 30 min effectively.