Competitive and non-competitive adsorption of Cd(II) and Pb(II) from aqueous solution using Zr-BADS metal organic frameworks

Abstract

Water and wastewater treatment facilities face practical challenges in removing heavy metals, and the search for efficient processes and materials is crucial to solving this issue. This study aims to prepare a recently innovated metal-organic framework Zr-BADS MOFs, then utilize it in adsorbing Cd(II) and Pb(II) ions from wastewater by applying single and competitive systems. The prepared MOF was characterized by Fourier transform infrared spectroscopy, X-ray diffraction, Brunauer−Emmet−Teller, and scanning electron microscope to unravel its textural and surface properties. The systems were applied in the batch mode of operation, and equilibrium was reached after around 30 min. The experimental data kinetically best fitted with the pseudo second order model, and the Langmuir model best described the isotherms. Here, maximum adsorption capacities of 60.756 mg·g⁻¹ for lead and 53.585 mg·g⁻¹ for cadmium were achieved. The prepared MOFs demonstrated excellent recycling performance after six cycles of adsorption-desorption processes toward both studied ions. These observations show that the prepared Zr-BADS is a promising material for the removal of lead and cadmium ions in single and coexisting systems.